Royal Society of New Zealand
Volume 86 (Quarterly Issue), Parts 3 & 4 Issued May, 1959
Published by The Royal Society of New Zealand,
Victoria University of Wellington, P.O. Box 196,
Wellington, New Zealand
Registered for Transmission by Post as a Magazine
Volume 86, (Quarterly Issue) Parts 3 and 4.
Issued May, 1959
Royal Society of New Zealand,
Published by The Royal Society of New Zealand,
Victoria University Of Wellington, P.O. Box 196,
Wellington, New Zealand
Editor: J. T. Salmon, D.Sc., F.R.S.N.Z., F.R.E.S.
C. A. Cotton, D.Sc., Hon. LL.D., A.O.S.M., F.G.S., F.R.S.N.Z.
High Commissioner for New Zealand, 415 Strand, London, W.C.2
Printed by Otago Daily Times and Witness Newspapers Co., Ltd., Dunedin, New Zealand
Notes on the Behaviour of Two Estuarine Crab Species
[Received by the Editor, April 15, 1958.]
The two estuarine crabs, Helice crassa and Hemipla hirtipes, at least temporarily, live singly in burrows which they defend from the intrusion of other members of then colonies.
Fighting in both species consists mainly of threat display or “ritual”.
Exaggerated ritual fighting during peak sexual periods does not seem to function primarily as territory defence.
Neither species shows any courtship displays.
Both species have efficient means for escaping or concealing themselves from piedators.
Observations of the biology of the crabs Helice crassa (Dana) (family Grapsidae) and Hemiplax hirtipes (Heller) (family Ocypodidae) were carried out during September, 1954, and from February to August, 1955—i.e., throughout a late summer, autumn, winter, spring Most of the work was done on the mudflats around the Otago Peninsula, but the two crabs are common in similar localities throughout New Zealand.
The two species occupy roughly similar habitats estuarine mud flats where they are confined between the tide marks and live in burrows or under stones. Hemiplax hirtipes is also occasionally found on sheltered rocky shores. The two crabs are similar in appearance.
Helice crassa is a smallish crab, about three-quarters of an inch in width across the carapace, olive-green to tawny-brown in colour with rather square proportions when seen from above.
In Hemiplax hirtipes the carapace is roughly an inch in width and its colour varies from pale blue-green, with a few very small spots, to tawny-brown or reddish-brown with either large masses of purple spots, a pattern of coalesced spots or large purple-blue patches. The legs are yellow-green or blue-green and the chelipeds deeper or lighter red on the dorsal edge, white on the ventral edge. The general proportions are rectangular with the long axis extended laterally.
Both crabs typically feed by extracting the organic matter from surface mud or sand, which is picked up indiscriminately by the chelipeds and sorted by the mouth parts. They also eat large pieces of dead organic matter, the bodies of dead lugworms, pieces of ascidians, etc.
Crabs of both species can be found occupying burrows. Helice crassa individuals were observed constructing burrows in the field and in the laboratory. The technique used by these crabs is similar to that described by Dembowski (1926) for the fiddler crab and Cowles (1908) for Ocypoda arenaria. On no occasion did I see Hemiplax hirtipes constructing a burrow, and I suspect that the crabs of this species occupy burrows built by the other.
In a vertical transect of mud bank, Hemiplax hirtipes burrows are concentrated near the lower tide limit and Helice crassa burrows near the upper tide limit, although there may be considerable overlap between the two distributions. Helice crassa is active, feeding and burrowing, mainly when exposed at low tide; Hemiplax
hirtipes is active when covered by water during the rising or falling tide. Their respective distribution concentrations, therefore, coincide with their feeding and other habits, allowing Helice crassa maximum time of exposure and Hemiplax hirtipes maximum time of coverage.
Both species live in quite densely populated colonies; the occupation ground is riddled with burrow openings. For Helice crassa there may be as many as 30 burrows in a square yard of ground surface. It is more difficult to estimate numbers of Hemiplax hirtipes since they do not correspond one to a burrow as Helice crassa tends to; and the Hemiplax hirtipes colonies are not as homogeneous. However, counts of visible Hemiplax hirtipes individuals in a thickly populated colony indicate a density at least as high as that for Helice crassa.
Although these animals congregate in such numbers, there is a minimum of social co-operation between them. Each individual cuts himself off by securing a burrow and defending it and a small area of ground around it from the intrusion of his fellows. At least in Helice crassa, this ensures the availability of a shelter for the crab in times of danger, and feeding space as well.
To determine the degree to which the animals' activities are localised around their burrows, a set of crabs from both species were differentially marked with fingernail polish on the carapace and leg joints, and close observations and records of their behaviour were kept over a number of days. I found that Hemiplax hirtipes individuals have a much looser connection with a specific burrow than do individuals of the other species. Helice crassa seldom moves more than 24 inches from its burrow. Hemiplax hirtipes, when feeding, wanders over comparatively large areas utilizing and defending not one burrow but any that happens to be at hand.
Both crabs defend their temporary or permanent possession of a burrow against other individuals. When a wandering crab draws near another's burrow, the occupier of the hole rushes out, or if feeding outside, runs to take up a position at the burrow entrance. This may be enough to frighten away the intruder but, if it continues to advance, the defending crab adopts a characteristic “threat” attitude. Bethe (1895) describes this in Carcienus maenas as the “Aufbaumreflex”. In both species the threat attitude presents to an animal standing in front of the crab the most obvious and—one cannot resist the temptation to say—frightening aspect of its form. The chelipeds are raised and held with the “fingers” open and reveal a colour pattern which accentuates their definition and size. At the same time the animal spreads or extends its legs to add further to the impression of size (Text-fig. 1, Figs. A and B). The adoption of this posture by the defending crab may be enough to send the rival crab scuttling away, but frequently the rival also adopts a threat attitude. The two crabs face each other and draw together until their chelae touch. Helice crassa individuals extend their legs so that the body is raised as high as possible, and raise and flex their chelipeds so that the large pincers are held a little out from the body with their external surfaces directed towards and abutting against those of the rival (Text-fig. 1, Fig. C).
Hemiplax hirtipes individuals at first hold their chelae open but flexed in such a way as to reveal to best advantage their startling distribution of white and red. As they move closer together the combatants extend their chelipeds outwards to the maximum extent. Thus they meet with the inside surfaces of their chelipeds turned toward and abutting against those of their opponent (Text-fig. 1, Fig. D). Hemiplax hirtipes does not rise on “tip-toe” but spreads its legs sideways as far as possible bringing the ventral surface of the body close to the ground and emphasizing the impression of width.
In this position the mouthparts of the two animals are brought quite close together. It seemed from the Helice crassa fights observed on the open ground, that its breathing water is often “blown” or “bubbled” into the opponent's face. Probably the breathing currents of Hemiplax hirtipes, clinching below the water level, also oppose one another. Opposition of breathing currents may play a part in this ritualised fighting.
Several Hemiplax hirtipes individuals timed in this “mutual threat” held it for over five minutes. Helice crassa individuals tended to take less time to decide the issue, and this is not surprising since these crabs, exposed on the open ground, are more vulnerable to predator attack. Such fights usually terminate in the retreat of one of the combatants with occasionally the dominant crab pursuing his opponent for a short distance. One contest observed between Hemiplax hirtipes individuals lasted an hour and ten minutes and consisted of a series of mutual threatenings and pursuits in which the same crab was dominant throughout. With Helice crassa individuals, which are more tied to their burrows, the chance of success in a fight seems to be an inverse function of the distance from the burrow mouth.
In both crabs real fights, involving beating and tearing with pincers, are reduced to a minimum. A whole crab is more likely to survive to breed than an injured one, so that reduction of real fighting has survival value for the species. Real fights were observed between Helice crassa individuals on occasions when the intimidation phase tended to be lengthened. One Helice crassa male was seen to seize another by a pincer, lift it bodily in the air, and thrust it onto the ground on its back. In other contests limbs were lost or thrown off. Physical struggles seemed to be inevitable when several Helice crassa individuals were put together in a laboratory aquarium with little room for escape, and many such crabs were killed or lost all their limbs. Crane (1941) makes the following observation on Uca: “Several instances have been observed where crabs with badly damaged chelae, or with chelipeds missing, were definitely bullied by other crabs”. In Helice crassa under similar circumstances, sick or weak individuals seemed to be the first to succumb.
It appears that Helice crassa individuals, male and female, behave in the same way defending a burrow against an intruder of either sex. The males seemed to be readier to fight than the females.
With Hemiplax hirtipes fights were observed to take place only between males. No female was observed in the “Aufbaum” attitude. A strange point about defence of property in Hemiplax hirtipes is that often a crab which has vigorously and victoriously defended a burrow may almost immediately wander away from it and apparently never return.
At times fighting takes on a rather different character. On May 23 and 24, 1955, both fine clear days, the following field notes were taken:
“8.15 a.m. Hemiplax hirtipes males engaged in fighting. Apparently no teiritorial boundaries are recognized, crabs entering a whole succession of burrows and following each other into the same burrow.
“9.31 a.m. Five crabs contesting the possession of one hole. One crab chases another into the burrow and, after much rushing to and fro with flourshings and measuring of pincers, the defending crab is chased deep into the burrow and forced to vacate by bursting through the roof of a side tunnel. The evicted tenant, after one unsuccessful attempt to regain his property, departs. Three smaller crabs now advance on the burrow and systematically worry the new owner. While two of the new intruders attract the large crab's attention at the tunnel mouth, the third crab enters by the side hole made when the original occupant escaped. The new tenant is forced to defend his prize by rushing backwards and forwards from one opening to the other and brandishing his chelae”. I watched this epic struggle for thirty minutes and it was still in progress when I left.
Pearse (1914) states that crabs frequently “dart about without a serious purpose and are sometimes downright mischievous”. This description seems to fit similar observations of Hemiplax hirtipes.
Activities of a similar nature were observed in Helice crassa. As with Hemiplax hirtipes the warmest and sunniest days provided the most examples, and peak periods of fighting and burrowing seemed to coincide with peak mating periods. During these times some Helice crassa males wander far from their burrows and may engage in a series of fights with other wandering males or make raids on other burrows, even going so far as to dig the end-plug out of blocked-up burrows to provoke the owner into defending his territory.
Not only is this fighting without the obvious purpose of more usual territorial defence; it tends to be longer drawn out and more ritualised—i.e., real blows follow threat to a lesser extent.
Most fights, whether on a territory or not, are punctuated by short pauses in which the crabs may perform feeding movements, but in such a rapid and agitated manner that very little mud or sand is conveyed to the mouthparts and no rejection pellets formed. Gordon (1955) described such movements in corresponding circumstances for Uca species and labelled them “displacement activities”—i.e., irrelevant movements performed as a result of a conflict of two drives, the tendency to attack the rival and the tendency to flee from him.
Mating in Helice crassa and Hemiplax hirtipes was observed to take place from August to May inclusive, with peak periods of sexual activity in October and May. Copulation occurs on the surface of the ground and was observed many times in the field and twice in the laboratory.
Both species exhibit sexual dimorphism with the pincers of the males being much larger than those of the females. Crane (1941) reviewed the literature on sexual dimorphism in crabs and concluded that in some crabs the exaggerated pincers of the male are used in courtship display while in other species their function is solely the enhancing of threat against rivals. In Helice crassa and Hemiplax hirtipes no courtship behaviour was observed. Nothing like the waving and signalling of the tropical fiddlers described by Crane (1941) was observed. Without preliminary overtures the male seizes the female with his pincers and adjusts her body forcibly to the position for copulation as figured by Pearse (1914) for Uca signatus. Sometimes the female struggles and escapes, but if the male is strong and vigorous enough she becomes submissive.
Agitated feeding movements similar to those in the fighting situation were sometimes performed by males attempting to copulate with resisting females. These are also reported by Gordon (1955) who again labels them “displacement feeding”, but this time resulting from the thwarting of an activated drive.
Both species are exposed when feeding and present likely prey for kingfishers, herons, gulls, fish and octopods. Hemiplax hirtipes was also seen to fall victim to a large crab Hemigrapsus sexdentatus. Awareness of movement is essential for their self-preservation.
Helice crassa reacts to any unusual movement within 20 or 30 feet by retreating into the burrow, the restricted area of the feeding range and speed of retreat usually being adequate to keep this species out of trouble. At the first sign of disturbance Helice crassa individuals stop feeding and stand motionless Such an alert can be communicated to a large number of feeding crabs, the majority of which do not detect the source of the disturbance. If the disturbing element continues to approach, the crabs all scuttle for their burrow entrances. Again, individuals
may react to the take-cover movements of other members of the colony instead of directly to the source of the disturbance. As a rule females seem more timid than males. The nice discrimination between disturbances and responses must be an asset in the economy of this crab—allowing more time on the open ground for feeding.
In times of danger a frightened Helice crassa individual will scuttle into the nearest available burrow whether occupied or not. On one occasion, when sufficient time had elapsed for the crabs to get over their fright, I saw four individuals emerge from the same burrow mouth.
Hemiplax hirtipes, which moves to a large extent amongst submerged vegetation and is not as nakedly exposed as Helice crassa, can be approached much closer and with much less caution before it runs for cover. If, however, their burrows are too far away, Hemiplax hirtipes individuals will either try to conceal themselves by burying on the spot or show fight. The burying technique is effective only in soft mud or sand below the water level. The crab first pushes its body backwards into the sand then, with alternate flexure and extension of the posterior legs, covers itself with sand so that its location can be identified only by the agitation of sand particles where the two exhalent breathing currents emerge. Crabs kept submerged on sand in the laboratory spent a large part of their time buried in this way.
If the animal chooses to show fight, it first adopts the “Aufbaumieflex” attitude, but if the source of the disturbance draws closer, the crab stretches itself upwards or sideways to its fullest extent, extends its chelipeds with the pincers wide open. and seizes some part of the intruder. This display is mostly bluff, as such crabs cannot inflict much damage on any of then enemies and, if escape is still possible, they usually discard the engaged limb and make off at top speed.
Hingston's concept of “colour conflict” (1933) can be applied to the colouiation and form of the two crabs. According to this theory most animals combine a need for concealment in some situations with a need for conspicuousness in others. One solution to the problem is for the animal to have the generally exposed parts of the body cryptically coloured and conspicuous patterns on parts of the body that are revealed by a special posture.
When Helice crassa is crouched close to the ground and partly buried, all the appendages are folded close to the body and the crab assumes as small and as flat a form as possible. The eye-stalks are shut into their grooves in the front of the carapace, and the pincers are folded under the mouth parts, which are pressed toward the ground. The back of Helice crassa and portions of the appendages still exposed are coloured crytic muddy green, blue green or raw sienna and are difficult to distinguish from the sand on which the animal lies. But when the same crab adopts the “Aufbaumreflex” attitude, the ventral surface of the animal is exposed with every part unfolded and extended and the crab looks as big and obvious as possible. The pincers, which are the most obvious and wicked-looking feature, are light yellow in colour and edged along the top with sharply contrasting darker green. The mouth parts are also light yellow with darker edges. Small patches of bright orange pigment are present at the joints of the chelipeds and walking legs visible from the front. The light colour and jagged form of the opened pincers make them stand out from the general darker shades of the rest of the animal, and the orange patches are very obvious. With the eye-stalks also raised to their full height, there can be no doubt about the conspicuousness of both the animal and its intentions.
Hemiplax hirtipes adopts a similar concealing attitude to that of Helice crassa with all obvious parts tucked out of sight, the body shape being reduced to as small and compact a mass as possible with only the dark green upper body colouring exposed. Often, however, the sand is lighter in colour than the crab and, unless it
can bury itself, the crab can still be seen. Hemiplax hirtipes usually shows warning behaviour first and tries to retreat or bury itself only if this fails. As a consequence it is more brightly coloured in the warning fashion than it is camouflaged for concealment. When disturbed, this crab turns in the direction of the disturbance and stiffens on outstretched legs with mouth parts lifted from the ground and with the pincers flexed and obvious. Moreover, the crab moves as the source of disturbance moves so that the startling pattern of the pincers is always on display. In this species the pincers carry a band of red and a band of white pigment which contrast sharply with the darker greens and browns of the body and the colour of the sand or mud which may be deepened by the crab's shadow. Closer approach brings about a striking and startling change of attitude, the colourful chelipeds being rapidly extended and the large pincers opened. If such intimidation fails the crab finally tries to run away and bury itself.
It is possible that the initial warning reaction of Hemiplax hirtipes and its fairly conspicuous general colouration are real warning signs of unpleasant taste properties in the crab (proaposematic colouration). For, whereas on numerous occasions predators were seen catching and devouring individuals of Helice crassa, on only one occasion was a predator (in this case the crab Hemigrapsus sexdentatus) seen to catch and eat an individual Hemiplax hirtipes.
I wish to express gratitude to Dr. B. I. Brewin, Professor B. J. Marples and Dr. N. Tinbergen for encouragement and help, and Mr. A. S. King, who typed the manuscript.
Bethe, A., 1895. Studien uber das Centralneivensystem von Carcinus maenas. Arch. mikr. Anat. Bonn, Band xxxiv.
Cowles, R. P., 1908. Habits, reactions and associations in Ocypoda aienaria. Papers from the Tortugas Laboratory of the Carnegie Institute of Washington, 2 (Publication No. 103), pp. 1–41.
Crane, J., 1941. Crabs of the Genus Uca from the West Coast of Central America Zoologica New York, Vol. 26, pp. 145–208.
Dembowski, J. B., 1926. Notes on the behaviour of the Fiddler Crab. Biol. Bul. Wood's Hole, 50, pp. 179–201.
Gordon, H. R. S., 1955. Displacement activities in Fiddler Crabs. Nature, Vol. 176, No. 4477, pp. 356–357.
Hingston, R. W. G., 1933. Animal Colour and Adornment. Arnold, London.
Pearse, A. S., 1914. Habits of Fiddler Crabs. Washington Smithsonian Inst. Rep., pp. 415–428.
Mr. C. G. Beer,
Magdalen College, Oxford.
Evechinus chloroticus (Val.), an Endemic New Zealand Echinoid*
[Received by the Editor, April 23, 1958.]
The anatomy of Evechinus chloroticus (Valenciennes, 1846) is compared with that of Heliocidaris erythrogramma and with published descriptions of Echinus esculentus. The differences between the three species are slight, but uphold the view that Evechinus and Heliocidaris should be placed together and apart from Echinus and its allies H. L. Clark (1912) first referred Evechinus to the Family Echinidae, and later (1925) referred both Heliocidaris, and Evechinus to the Family Strongylocentrotidae. Helicidaris, which has polyporous ambulacral plates and a circular ambitus, obviously conformed to Clark's Family Strongylocentrotidae. Evechinus, although oligoporous, was included because of the specialization shown by the larval form and the pedicellariae. Mortensen (1943) contends that both genera should be placed in the Family Echinometridae on account of the strongly developed single lateral tooth of the gemmiform pedicellariae, the paired nature of the poison glands, and the structure of the larval form.
Evechinus shares with Heliocidaris:
The large collateral canal, which is conspicuous in both forms; it has, however, also been described from Echinus, although not from all members of the Echinidae (Bonnet, 1925).
The gonads elongate from apex to lantern, although those of Evechinus are strongly coalesced while those of H. erythrogramma remain quite separate.
The genital papillae, which are of very similar form in the two genera; the genital pores are also of the same order of size.
A well defined ridge on the internal surface of the apical plates; in Evechinus the apical connection between the axial organ and the stone canal does not appear to be developed, although it has been described for Echinus (Chadwick, 1900,et al.)
The alimentary canal, which is voluminous and greatly convolutes in both species, unlike that of Echinus; both forms bear well developed processes on the epiphyses of the lantern, which in those members of the Echinidae which possess them are only slightly developed (Mortensen, 1943); there are also small differences between Echinus and Evechinus in the structure of the pharynx and in the histology of the alimentary canal.
Therefore it is considered that Evechinus and Heliocidaris are closely related genera, and although both Clark's and Mortensen's classifications have been admitted by their authors to be artificial, it is thought that Mortensen's criteria provide a more convenient basis for separation at the familial level than do those of Clark.
Evechinus chloroticus, the common littoral sea-urchin inhabiting the New Zealand coasts, is a regular echmoid belonging to the Family Echinometridae, which is included in the Order Camarodonta (Mortensen, 1943). Mature specimens are figured on Plates 12 and 13. This species is the largest known echinometrid. The largest on record is one described by Farquhar (1897) of 145 mm diameter, although an average sized specimen is smaller, rather less than 100 mm in diameter.
Despite the work of numerous authors from Valenciennes (1846) to Mortensen (1943), the systematic position of Evechinus chloroticus has not been fully estab-
[Footnote] * This study was undertaken in the Zoology Department, Victoria University of Wellington.
lished. No work, except for a brief mention by Mortensen (1943), has been done on the anatomy of the animal. As it is such a well-known member of our littoral fauna, and is a standard dissection during the Zoology course at the Victoria University of Wellington and probably also at other universities, it seemed time that its anatomy should be investigated. Accordingly, a detailed study has been made of the gross anatomy and morphology of the animal, together with histological study of the alimentary canal and the tissues of other organs where necessary. No parasites had previously been recorded from Evechinus, but during this study two endocommensals and one ectocommensal were found. At the same time five specimens of Heliocidaris erythrogramma (Valenciennes) were obtained from Sydney, so that a brief comparison between the anatomy of the two echinometrids could be made, although unfortunately the specimens of H. erythrogramma were not received in a good state of preservation. An endocommensal rhabdocoel, similar to that found in Evechinus chloroticus, was found present in large numbers in the gut of all these sea-urchins. They appear to represent two different and undescribed species of the genus Syndesmis, of which the species S. echinorum is commonly found in the gut of European echinoids. As text-books usually take species of Echinus, especially E. esculentus, as the example of a “typical” echinoid, I have made my main comparisons with this genus.
The families of the Sub-order Echinina all consist of camarodont echinoids with compound ambulacra of the echinoid type. The test is unsculptured, while the tubercles are imperforate and smooth. The gill slits are not sharp or deep, and the spines are solid. The families within the Sub-order are mainly distinguished by the structure of their gemmiform pedicellariae, which in all echinometrids possess a single, unpaired lateral tooth. Evechinus chloroticus is recognized by its almost horizontal pore-arcs, the pore-pairs of which are arranged in three vertical series, by the green colour of the test, and the fact that the spicules of the tube-feet are simply bihamate (Mortensen, 1943). However, as the result of closer investigation, it has been found that these spicules bear small distal projections, in much the same way as the closely related Selenechinus armatus, so that they can not now be regarded as good specific characters.
Fell (1953) has made certain suggestions as to the possible history of the genus. He states that Evechinus is known as a fossil from the Nukumaruan (mid-Pliocene), appearing, together with Arachnoides, Pseudechinus and Echinocardium, after the extinction of the early-Tertiary warm-water echinoid fauna. It is restricted to the New Zealand region, throughout which, however, it is widely distributed, reaching as far as the Kermadec Islands in the north and to Stewart Island in the south. It also occurs at the Chatham Islands. The fact that this endemic genus is eurytopic points to a relatively early differentiation within the New Zealand region, which is thus probably the original home of the genus. With its pelagic larvae, which have obviously been successful in distributing it widely within the New Zealand region, Evechinus would seem admirably equipped to take advantage of any dispersal mechanism operating between the Australian and New Zealand regions. Although it has been present in New Zealand since the Pliocene, it has not so far been able to traverse the Tasman, so that it has been deduced, on this and other evidence, that no such east to west dispersal mechanism can operate between the two regions.
Evechinus is usually referred to coloquially as the “sea-egg”, although the Maoris, who relish the gonad for food, refer to it as “kina”. It is eaten raw, preferably while the animal is still alive. Many Europeans have also acquired the taste for “kina”, and it is occasionally on sale in fish shops in Wellington, retailing usually at the price of sixpence each.
I would like to take this opportunity of thanking Professor H. B. Fell for his invaluable help and advice; Miss Isabel Bennett, of the Department of Zoology. Sydney University, for sending me preserved specimens of Heliocidaris erythrogramma
from Sydney; and Mr. M. D. King, for photography. I am also grateful to those members of the Zoology Department, Victoria University of Wellington, Mr. B. E. Maxwell, and Mr. J. C. Yaldwyn in particular, who have kindly collected material, and all whose advice and encouragement have helped me during the course of this study.
Materials and Methods
Specimens of Evechinus chloroticus were obtained from Oriental and Balena Bays, where they are present in such numbers that collection has never been a problem. They occur in about knee depth of water at low tide. It was found best to collect them in calm weather when they could easily be seen, in among the stones and clinging on to rocks. Their habit of holding stones and old shells on the aboral surface, and of nestling in between the stones, makes them difficult to detect if the surface of the water is broken.
Animals required for preservation were transported back to the laboratory in a plastic bag, where they were anaesthetized in tepid fresh water. A small hole was made in the test wall and the animal fixed and preserved in 8% formalin. Any which were required to be kept alive in an aquarium tank were transported to it in a billy of sea water. In general sea-eggs seem to be able to remain alive for quite a considerable time out of water. They may sometimes be seen in fish shops moving their spines quite actively, hours after they have been taken from the water.
Occasionally, when I was interested only in knowing the degree of maturity of the animals, specimens were opened at the collecting ground and gonad samples taken and preserved in alcohol. At the same time a measurement of the diameter of the animal was taken. All measurements of height, diameter, etc., of the test were taken as if the spines had been removed.
Dissections were always carried out under water. To obtain the correct orientation of the internal organs the animal was fixed to the dissecting dish with a small quantity of melted wax, in such a way that radius III was always the anterior ambulacrum. Once the test wall had been perforated by a sharp instrument such as a scalpel, coarse forceps were used for breaking away the remaining parts. A magnifying plate was found useful for examining dissections, drawings of which were made to scale by hand.
Whole tests were cleaned by boiling specimens for two or three minutes in 10% potassium hydroxide solution. It was found best to make a small hole in the peristome first, so that the solution could penetrate easily to the internal organs. Any adhering epithelium and spines were then washed away under a strong jet of water, and if necessary maceration continued for a few days in water. The apical ossicles are very delicate and likely to drop out if violent maceration is carried on for too long.
Whole specimens were also prepared following a method described by Bonnet (1925). A hole was pierced at the apex of the test of an animal previously preserved in formalin. It was made in a radial position to avoid penetrating the gut, and the liquid in the body cavity drawn off with a syringe. The interior of the animal was then washed out several times with warm water, until the wash water was no longer discoloured. A gelatine solution (3 parts gelatine: 1 part water) was then injected to completely fill the body cavity, and the hole at the apex plugged with cotton wool. The preparation was placed in a refrigerator overnight, or until the gelatine was set hard. It was found that a little of the hot liquid had leaked out before setting, and so more was added at this stage to completely fill the whole interior. After the second gelatine addition had set, the preparation was placed in a 10% formalin solution for one or two days to harden the gelatine. This was followed by a bath of 5% hydrochloric acid to dissolve the test, a process taking three or four days. The acid solution needed to be renewed at least once. When
all the calcareous plates had been dissolved away, the outer epithelium and membranes between plates were carefully picked away, so that the underlying organs, the gonads, coils of the gut and radial ambulacral canals and their associated ampullae, were revealed, visible through the gelatine. The whole preparation was then kept in 8% formalin. Evechinus chloroticus is, however, not a satisfactory subject for preparation in this way, as the gonads are large and coalesced and so obscure most of the other organs. Small specimens, in which the gonads are still quite small, should, however, make good preparations.
Material was prepared for all histological examination by fixation in Zenker's mixture, followed, after the appropriate washing, dehydration and clearing, by imbedding in rubberized paraffin, made according to the directions given by Sass (1940). This was found to give much better ribboning than ordinary parafin. Sectioning at from 6μ to 12μ was done with a Cambridge rocker microtome. To remove the mercuric salts left by the Zenker's fixative, the sections were treated before staining with tincture of iodine in 70% alcohol; the brown iodine coloration was removed by 50% alcohol. Ehrlich's acid haematoxylin and eosin in 95% alcohol for counterstaining was found the most useful general stain. Canada balsam was the usual mounting medium. For parts of the gut, especially the oesophagus and also the gonad, Mallory's triple stain was used with success. The sections, however, faded when mounted in an acid medium such as Canada balsam and so euparal had to be used instead. In general it was found that extremely rapid dehydration was necessary for sections stained with Mallory's. They were briefly washed in tap water, dipped in and out of 50% alcohol and taken straight to two successive washes of 95% alcohol, from which they could be mounted straight into euparal.
Decalcification of fixed material for histological purposes was accomplished by placing the material in Schurig's solution (95 parts of 80% alcohol, 2 parts of conc. hydrochloric acid, 3 parts of picric acid). The process took approximately two weeks, during which time the solution was changed two or three times. A 30% solution of sodium hexametaphosphate was also tried for decalcification, but was found too slow-acting for the thick test wall of Evechinus.
All histological drawings were made using a Watson-Victor monocular microscope and a camera lucida. A Watson-Victor low power binocular microscope was used for drawing of small anatomical structures.
Ambulacral and interambulacral areas. Divisions between ambulacral plates were often difficult to see, especially in large specimens, but one or two specimens from the College collection, which had been kept in formalin for some time, were found particularly useful in this respect. The formalin had evidently become acidic and attacked the plates, so that the membranes separating them were partially revealed. Correlation of the patterns of pore-pairs on the inner and outer surfaces of the test was achieved by passing a hair through every pore on the exterior of a plate and noting its position of emergence in the interior. Counts of the ambulacral plates were made using Mortensen's method (1943) of recognizing each member of the inner series of pore-pairs as a separate plate. Sections of interambulacral plates were obtained by mounting in Canada balsam and grinding to the required thinness. This was first done horizontally, and when no results were obtained, further sections were ground parallel to the median suture, and then parallel to the suture between plates of the same column.
Peristome. This was observed under a magnifying plate and drawn to scale by hand. The peristomial plates were obtained by boiling small pieces of the peristome in 10% potassium hydroxide for a few minutes.
Spines. Spines were removed from the test and cleaned in boiling potassium with a tubercle was obtained in the course of sectioning a decalcified ambulacrum hydroxide. A longitudinal section through the base of a spine at its articulation
Transverse and longitudinal sections of cleaned spines were obtained by mounting in Canada balsam and grinding to the required thinness.
Pedicellariae. Whole pedicellariae were studied, both in water under a binocular microscope and mounted in glycerine jelly under higher magnification. Separate valves were macerated by boiling for a few minutes in 10% potassium hydroxide. They were subsequently mounted in glycerine jelly. Fell's (1941) method of studying calcareous structures through polarized light was found useful in determining the nature of the valves, when they appear as glowing golden structures standing out against a deep blue background. Some gemmiform pedicellariae were decalcified, sectioned at 6μ and stained in Ehrlich's haematoxylin and eosin.
Sphaeridia. Sphaeridia were detected by scraping carefully with a scalpel along the centre of each ambulacrum near the peristome, all the time examining the area through a hand lens under strong light. Any sphaeridia detected were then cleaned by leaving in 10% potassium hydroxide solution for a few hours. The histological structure of the sphaeridia and their relationship to the test were discovered by decalcifying and sectioning part of an ambulacrum from near the peristome.
Alimentary System. Ossicles of the lantern were obtained by cutting away as much of the adhering muscle as possible, and macerating the whole structure in 10% potassium hydroxide. For details of the dissection of the gut see the section on the alimentary system. The histology of the alimentary canal was determined by sectioning and staining small portions from representative regions in both Mallory's triple stain and Ehrlich's acid haematoxylin and eosin.
Ambulacral System. To show the relationships between the ambulacral canals, their appendages and other radial structures, small sections of the ambulacra were placed in Schurig's solution (Hiraiwa, 1932) to decalcify the test. The decalcified material was then imbedded and sectioned. The relationships of the madreporite, stone canal and other apical structures were also demonstrated by this technique.
Glycerine jelly was found to be the most satisfactory mountant for the tube-feet, as they could then be taken straight from water, and thus prevented from shrivelling. The buccal tube-feet, however, were too dense to show the xtalline plate clearly when mounted in this way; so maceration by Fell's method (1940) was tried. The tube-foot was removed from the peristome and severed just below the sucker, so that the plate could lie face down in the bottom of an evaporating dish, and would not break up when the supporting tissues were removed. A few drops of 10% potassium hydroxide were then added, and the evaporating dish placed in the oven. Further drops of 10% potassium hydroxide were added as the original solution evaporated, until maceration had proceeded sufficiently to reveal the plate, usually 2–3 hours.
The ampullae were removed by carefully scraping them away from the interior of the test, and examining in water under a low power microscope. One from each region was then selected and mounted in glycerine jelly.
Coelomic Cavities. The larger coelomic cavities are visible to the naked eye. The smaller ones, such as the terminal sinus, aboral ring, etc., were revealed by sectioning a previously decalcified apical system.
Coelomic Fluid. The test of a living animal was perforated in the apical region of an ambulacrum to avoid the gonad and the coils of the gut, and several cubic centimetres of coelomic fluid drawn off with a syringe. This was then observed fresh under a high power microscope.
Axial Organ. Sections were cut and stained in both Ehrlich's haematoxylin followed by eosin, and Mallory's triple stain. To determine the apical relationships of the gland, an apical system, with its internal tissues and adhering stone canal and axial organ, was removed and decalcified. This material was then sectioned and stained with Ehrlich's haematoxylin and eosin.
Lacunal System. The description of the lacunal system of Echinus esculentus is apparently based to a large degree on injected specimens which were found quite easy to prepare by Cuénot (1948). “Le réseau absorbante de l'intestin, l'anneau oral et le réseau de la glande brune se remplissent facilement en poussant l'injection dans la lacune marginale interne, très visible au bord du mésentère, ou encore en perforant avec la canule la périphérie de la glande brune …” Echinus esculentus, however, attains the greatest size of all echinoids and so would possess haemal canals of dimensions suitable for injection. In Evechinus chloroticus the internal marginal canal, although quite readily visible, is only of the order of 0.1 mm in diameter and so quite impossible to inject by ordinary methods. Attention was then directed to the lacunal network of the brown gland, which Cuénot also found possible to inject. The first injection fluid tried consisted of a gelatine vehicle (1 part gelatine: 10 parts water) carrying a colouring mass of indian ink. The animal was anaesthetized and the aboral test removed, leaving the apical system and its connection to the brown gland intact. A small hand syringe with a very fine needle was used to make the injection. However, the sudden strong pressure was not suitable for penetration of the fluid. An added difficulty was the necessity to keep the whole apparatus warm to prevent the gelatine from congealing. A second animal was selected and prepared in the same way. The fluid used, however, was pure indian ink, and a slow pressure was supplied by an aspirator. It was still impossible, however, to obtain a good penetration of the gland, let alone the whole lacunal system, so it was concluded that the periphery of the axial organ is too dense and its lacunae too small for such a technique. Luckily, however, the internal and external marginal canals, and the collateral canal, were easily visible to the naked eye, while sectioning of the gonad, the gut and the axial organ had previously revealed the lacunal network within their walls. The haemal ring about the oesophagus at the top of the lantern still remained problematical. To observe this a lantern was decalcified and its upper portion imbedded and sectioned.
Nervous System. To observe the histology of the radial nerves and their exact relationship to other radial structures, small pieces of ambulacra were decalcified and sectioned. The nerve ring about the mouth, and parts of the deeper oral nervous system were similarly observed by decalcifying a lantern and sectioning its adoral half. It was hoped that it would be possible to demonstrate the peripheral nerves passing under the epithelium over the exterior of the test. For this both fresh and fixed material was used.
Fresh Tissue, Methylene Blue Method (Smith, 1949). A small section of the test was placed in a petrie dish containing 50 ml of sea water to which had been previously added 0.5 ml of 1% methylene blue. The material was left in this solution for about five hours.
Fresh Tissue, Silver Nitrate Method (Bolles Lee, 1950). Small sections of the test were washed for half an hour in a 5% solution of potassium nitrate to remove the unwelcome chlorides present in sea water. They were then washed in distilled water and placed in a 1% solution of ammoniacal silver nitrate, which was agitated under bright light until the material began to turn grey. It was then washed in distilled water.
Neither of these methods was successful, however. Evidently the nerves were neither sufficiently stained nor impregnated to show up through the darkly pigmented epidermis.
Fixed Tissue, Silver Nitrate Method. Ramón y Cajal's method, as described in “The Microtomist's Vade-Mecum”, was followed. Small pieces of test were fixed for 48 hours in ammoniacal alcohol (50 ccs of 96% alcohol to which 4 to 5 drops of ammonia have been added), the material having been previously dehydrated in 70% alochol for 6 hours, and 85% alcohol for one hour. It was then silvered by placing in a 1 5% solution of silver nitrate, which was kept at 32° to 35° C. in an
oven for five days. At the end of this time the material had become light grey in colour. It was washed for a few minutes in distilled water and placed in the following reducing solution for 24 hours:
Hydroquinone, 3 gms.
Distilled water, 100ccs.
Formalin, 5 to 10ccs.
This was followed by quick washing and hardening in successive concentrations of alcohol. After this procedure there was still no evidence of nervous structures; so bleaching of the epidermis was tried. Two or three drops of hydrochloric acid were added to a few crystals of potassium chlorate in a test-tube, and as soon as the green colour of evolving chlorine could be seen a few cubic centimetres of 70% alcohol were added. The material was left in this solution for one to two days but, although bleaching was successful, the process evidently removed any of the silver which may have been precipitated on the nerves.
After the failure of all these methods I decided that demonstration of the peripheral nerves was outside the scope of this thesis.
Reproductive System. For details of dissection see section on reproductive system. To determine the sex and also the degree of ripeness of animals, small pieces of the gonad, taken from near the aboral pole, were teased out on a slide and examined under a microscope. The histology was investigated by sectioning and staining in both Mallory's triple stain and Ehrlich's acid haematoxylin and cosin.
The body of Evechnius chloroticus is hemispherical, adult specimens having much the same outline and size as an average sized grapefruit. The surface of the animal on which the mouth is situated is known as the oral or adoral surface, and in life is always held next to the substratum. It is flattened and usually distinctly sunken. The centre of the mouth lies at the adoral pole which is separated from the aboral pole, at the other extremity of the body, by the principal axis, which also corresponds to the vertical diameter or height. The anus is situated at the aboral pole. The outline seen when the test is viewed from above is the ambitus, and its diameter corresponds to the horizontal diameter of the test. It is usually quite circular, but may be pentagonal with smoothly rounded corners (Plates 12–13). The horizontal diameter, or simply diameter, is considerably greater than the vertical diameter, usually almost twice as much, so that in a specimen of 83 mm horizontal diameter the vertical diameter was only 44 mm, i.e., 1:1 8. The profile is usually well rounded, but occasionally specimens may be either subconical or depressed aborally.
The whole exterior of the test is covered by a dense carpet of spines and pedicellariae (Plate 12), except in the area immediately surrounding the mouth, which is membranous and quite devoid of spines, although some pedicellariae are present. This area is known as the peristome and from its centre the five pointed teeth of the masticatory apparatus project. During life the tube-feet may be seen in five broad zones on the test waving freely in the water often beyond the outer limit of the spines. In preserved specimens they are contracted and not so obvious.
In denuded specimens, which are often to be found washed up on beaches after the animal has died, the peristome has usually disintegrated so that it is represented only by a wide decagonal hole on the adoral surface (Plate 13). From it ten double columns of plates, bearing the numerous tubercles which support
the spines in life, are seen passing up to the aboral or apical extremity. Five of these columns are seen to consist of a double series of poriferous areas lying on either side of a tuberculated interporiferous area. These are known as the ambulacral areas or simply ambulacra, and each lies in a radius of the animal. The columns alternating with them are interradial in position and bear numerous tubercles. They are called interambulacral areas.
A small circle of plates called the calyx, or apical system, is present at the aboral extermity of the test (Plate 12). It surrounds the anus and contains within it a specially modified sieve plate or madreporite which is readily distinguished by its large size and porous surface. Using these plates as reference points, Lovén (1892) established the method of orientation, now known as Lovén's Law, which can be applied to all echinoids. If the animal is placed on its adoral surface in such a way that the madreporite and the interambulacrum with which it is continuous forms the right anterior interradius it is found that one ambulacrum is anterior and one interambulacrum posterior. The ambulacrum immediately to the right of the posterior interradius is then counted as lying in radius I and numbering of the radii continues in an anticlockwise direction so that the anterior ambulacrum comes to lie in radius III and the ambulacrum to the left of the posterior interambulacrum is in radius V. The three most anterior ambulacra constitute the trivium while the two posterior ones form the bwium. The interambulacra are numbered in the same way following after the ambulacra, so that the madreporite always lies in interradius 2 and the posterior interambulacrum in interradius 5. For clarity it is conventional to use Roman numerals for radu and Arabic numerals for the interradii.
The orientation described here is based on Lang's (1896) interpretation of Lovén's Law. Chadwick (1900), however, describing the radu of Echinus, has counted the right-hand side radius of the trivium as I, so that the most anterior radius becomes II instead of III. Chadwick gives no full list of references, so it is impossible to tell what authority he was following. However, the English translation of Lang appeared in 1896, four years previous to Chadwick's own publication, and as some passages of his text are almost identical with the translation it would appear that he had consulted Lang and that his different interpretation of the orientation is due to misunderstanding or else merely a slip of the pen.
Colour. The primary and larger secondary spines are dull green with whitish tips, while the club-shaped secondary spines are made conspicuous by their brilliant white tips. The external epithelium covering the animal is deeply pigmented so that the peristome appears quite red, as do also the extended tube-feet. Under adverse conditions this pigment is released, probably due to disintegration of the epidermis, and so is not obvious in preserved specimens. One specimen was found which was quite brown in appearance, particularly the primary spines. This was thought to be due to a thin layer of the pigmented epidermis carried further than usual up the side of each spine, for when the spines were removed from the animal the epidermis covering them soon disintegrated to reveal their normal green coloration. Properly cleaned denuded tests are green in colour, varying from dark green to quite pale shades. Around the peristome the ambulacra remain white. Brightly coloured specimens are very beautiful with their intricate pattern of tubercles and pores.
(Text-fig. 1, figs. 2–5.)
The ambulacra are five double rows of plates in each radius, extending down the test from the ocular plates of the apical system to the edge of the peristome. Each ambulacrum consists of three distinct zones of almost equal width. There are two outer or perradial poriferous zones (PZ), where the ambulacral plates are perforated by the canals leading from the ampullae to the tube-feet, and an inner
or radial interporiferous zone (IPZ), which bears most of the spines of the ambulacral area. The general pattern of arrangement of the tubercles of these spines is discussed in the section dealing with the spines. The suture line (SL) separating the two columns of plates passes down the centre of each interporiferous zone. Mortensen observes that the poriferous zones are about “two-thirds as broad as the interporiferous zones in the ambital region”, but adorally he describes them as “somewhat restricted”. This is certainly true, but the interporiferous zone is also equivalently restricted so that the relationship still holds (Text-fig. I, Fig. 3). Aborally both zones taper to nothing (Text-fig. 1, Fig. 2).
Each ambulacral plate, or major, is composed of three smaller plates, each bearing a pore-pair. Such composite plates are termed trigeminate or oligoporous. In the Family Echinometridae the plates are more usually polyporous, the genera Selenechinus and Evechinus being the only exceptions, apart from the genus Echinostrephus which has one species, Ech. molaris, oligoporous, while the other, Ech. aciculata, is polyporous. The fossil species Echinometra prisca also is usually oligoporous, but occasionally plates are found bearing four pore-pairs. Evechinus and Selenechinus are more advanced in this respect than Echinostrephus molaris, however, for neither genus has a primary tubercle occurring regularly on every ambulacral plate, but instead, as Mortensen (1943) describes it, on “every second-fourth plate”. The plates without the primary tubercle are smaller and much more compressed than those plates which bear them. A small part of the tubercle is frequently shared in Evechinus so that superficially the plates appear polyporous. This condition is described as pseudo-polyporous. On the other hand, the oligoporous condition, as found in all species of Echinus, is most usual in the Echinidae, although in both Sub-families Echininae and Parechininae the polyporous condition has arisen. (Mortensen, 1943.)
To say that the tubercles are borne on every second-fourth plate is, I think, an over simplification. I have found that near the peristome, the tubercles in general occur on every second plate, but occasionally several may be found in line all bearing primary tubercles (Text-fig. 1, Fig. 3), thus emulating the simple condition of Echinostrephus molaris (Mortensen, 1943). Near the ambitus the tubercles frequently occur quite regularly on every third plate, though occasionally a second plate will bear a tubercle and sometimes even a first. Towards the apex the arrangement becomes more irregular and the number of plates between tubercles is frequently four or five (Text-fig. 1, Fig. 2). In general the frequency of the primary tubercles increases as the ambulacrum approaches the peristome.
Mortensen (1943), commenting on the plates without tubercles, says that they are “often excluded from the midline of the area, or even divided so that only a small inner part remains in contact with the median suture”. This is the case in one specimen figured by him, which has one compressed plate near the ambitus just occluded from the median suture. I was not able to observe any such plates. In one or two cases where the suture between plates was difficult to see externally such appeared to be the case, but examination of the interior soon showed that the plate in question did actually attain the midline.
The manner in which the plates are fitted together conforms in general to the typical echinoid pattern, as figured by Cuénot (1948). The two outer plates are primaries (Text-fig. 1, Fig. 4, PS, PL), extending from the outer suture to the midline, while the third plate is inserted between them and completely occluded from the median suture. Such a plate is known as a demiplate (DP). However, majors which do not support primary tubercles are a little different (LP) in that the small upper primary plate does not usually extend as far as the midline, and so become a second demiplate. The lower component of each trigeminate plate is described by Mortensen (1943) as usually occluded from the outer edge of the area,
Text-fig.. 1.—Ambulacrum and Apical System. Fig. 1—Apical system of specimen 94 mm diameter. Fig. 2— Ambulacrum at the apex of the test. Fig. 3—Ambulacrum at the peristome. Fig. 4—Interior view of ambulacral plates near the ambitus. Fig. 5—Polyporous ambulacral plates. (All measurements expressed in millimetres. Figs. 1–4 all drawn to the same scale.) Abbreviations: A, anus; AD, adoral edge; ADP, additional demi-plate; AP, apical pore; DP, demiplate; EM, extension of madreporic surface; FIS, first pore-pair of inner series; FM, first major; FMS, first pore-pair of median series; G, genital; GP, genital pore; IS, inner series; IPZ, interporiferous zone; LP, low, compressed plate; MS, median series; OC, ocular plate; OP, ocular pore; OS, outer series; PB, periproctal membrane; PL, large primary; PM, peristomial margin; PR, partially resorbed pore-pair; PS, small primary; PT, periproctal plate; PZ, poriferous zone; SL, median suture line; SPT, small primary tubercle; STR, secondary tubercle of radial series; STZ, secondary tubercle of interporiferous zone; TBP, tubercle for pediccllaria; TP, plate bearing primary tubercle.
but while this may sometimes be the case it is usually seen that although the plate appears occluded on the outer surface of the test, internally it clearly shares in the suture line.
The more regular arrangement of the pore-pairs on the internal surface of the test helps in determining the boundaries of plates, especially near the peristome, where they are very obscure. It is seen (Text-fig. 1, Fig. 4) that the members of each pore-pair are here widely separated and at first I found it difficult to correlate them with their external openings. By passing a hair through the canals leading to the interior, however, it was possible to establish the basic pattern. The outermost members of each pore-pair in the two most apical plates of a major pass almost straight down through the test, while the inner members travel obliquely a distance of several millimetres (OS, MS). On the large primary plate, however, it is the inner member which passes directly down, the other canal having to travel obliquely to almost meet the outer member from the central demiplate (IS). From the interior of the test, too, it can be noted how the openings of the pore-pairs from one plate abut against the neighbouring, less apical plate, and may even seem to be included in it. This is particularly true of the pores on the largest primary, almost all of which are contributed by the small primary, or outer demiplate, of the next major.
The are formed by the pore-pairs on each plate is almost horizontal, so that the pores form three vertical series. This is distinct from the condition in Selenchinus where the pore arcs are almost erect. In species of Echinus it is a variable character. Ech. atlanticus has very erect pore arcs which form almost a straight line, but in most forms they are distinctly oblique. They may, however, become so oblique as to be almost horizontal so that the pore-pairs here also come to form three vertical series. This is the case in large specimens of Echinus esculentus (Mortensen, 1943).
The inner and outer columns of pore-pairs are quite regular, while the median series is much more uneven. The sequence of events during growth may be seen in an average-sized specimen by tracing the arrangement of the pores from the apex down towards the peristome (Text-fig. 1, Fig. 2). The first three or four pore-pans, situated on the outer edge of each plate, are in a single vertical series and belong to separate plates which have not yet become compacted into majors. In the following seven or eight majors the lowest plate—i.e, the large primary—has tended to become excluded from the outer suture, but instead has extended considerably to-wards the midline. This has caused its pore-pair to move in towards the radius and thus constitute a regular inner series (IS). The pore-pair of the upper plate in each of these majors, however, remains quite close to the outer suture so that it helps to contribute to the outer series (OS). The median series (MS) first becomes evident in most specimens when the ambulacrum has progressed at least 10 mm or even further down the test. The upper primary or demiplate also tends to become excluded from the outer suture so that its pore-pair moves in a little towards the midline to constitute the median series, divergent from the outer column of pore-pairs, which is then composed only of pore-pairs from the central demiplate of each major. This arrangement holds for the remainder of the test, with the median series eventually becoming quite regular towards the peristome.
In a very small specimen of 18 mm diameter it is difficult to distinguish a median series at all, for the pore-pairs all remain in contact with one another and are not at all separated as in older forms. Just below the ambitus, however, the poriferous zone widens and from this region to the peristome a median series can just be made out. It would seem, then, that growth of plates is not merely by deposition from the surrounding membranes, but must be by the addition of more calcite between the meshes constituting the whole plate, thus forcing the pore-pairs to move apart. In this case the plate must remain “alive” at least for some considerable time and grow continually by action of the spiculoblast living within it.
Although the majors are characteristically trigeminate, occasionally true polyporous plates are found, bearing four or even five pore-pairs. This recalls the condition found in the fossil species Echinometra prisca, where, however, the polyporous plates may have a higher incidence (Mortensen, 1943). Such a quadrigeminate plate is shown in Text-fig. 1, Fig. 5. In this major it is the upper primary plate (PL) instead of the lower (PS) which supports the main part of the primary tubercle, but otherwise the plate retains its usual form except that a fourth plate has been added as a small demiplate (ADP), almost occluded from the outer suture, to the apical edge of the major. However, another polyporous plate which bore five pore-pairs had quite an abnormal arrangement. It consisted of three primaries, all with pore-pairs belonging to the outer series. One demiplate was sandwiched between the two most aboral primaries and another large one lay along the adoral edge of the plate. Both were, however, occluded from the outer suture and remained instead in broad contact with the midline. The pore-pair of the most apical demiplate belonged to the middle series, while that of the lower one contributed to the outer series. The plate did not bear a primary tubercle. The presence occasionally of polyporous plates helps to emphasize Mortensen's (1943) contention that the “oligoporous or polyporous condition of the ambulacra is not of primary importance for classification”, but has arisen instead many times in separate evolutionary stocks.
The number of ambulacral plates must obviously increase considerably as the animal ages. In a specimen of 18 mm diameter there were 27 ambulacral plates, while in a large specimen of 112 mm diameter there were 103—i. e., while the diameter has increased six times, the number of ambulacral plates has tripled. Using Mortensen's (1943) figures for the extremely small specimen of 6 mm diameter which he records, it is found that the diameter increases 18 times while the ambulacial plates increase to over six times the original number.
(Text-fig. 2, figs. 5–8.)
The plates of the interambulacra are present in five double rows alternating with the rows of ambulacral plates and thus occupying an interradial position on the test. A fully formed interambulacral plate is roughly three times as large as an ambulacral plate and very much simpler. Each is a single plate, undivided by the suture lines which traverse the composite plates of the ambulacra.
The interambulacral plates are the important spine-bearing plates of the animal and in addition carry numerous pedicellariae. The arrangement of the tubercles is described in the section dealing with spines, but a brief summary will be given here of their distribution in a single column of interambulacral plates. Admedially, there is a row of secondary tubercles which is, however, not always present, especially in specimens of small diameter. It is not present in the interambulacral plates figured here (Text-fig. 2, Fig. 7), which were taken from a specimen of 60 mm diameter. Very close to these, moving out towards the radius, is a vertical series of small primary tubercles (SPT) followed by a row of secondary tubercles, each of which is developed towards the aboral edge of the plate (STP). A large primary tubercle (LPT) is present in the centre of each plate and is particularly conspicuous on the aboral part of the test. Finally, on the outer edge of each plate there are one or two secondary tubercles of the adradial series (STA). Where two such tubercles are present one is usually situated right next to the suture line between the ambulacrum and interambulacrum, with the other a little further in and rather more aboral. Between these series of tubercles numerous small secondary tubercles (MT), together with mihary tubercles for the pedicellariae (TBP), are scattered on every available space.
Text-fig. 2.—Interambulacrum and Peristome. Fig. 1—Peristome. Fig. 2—Buccal ambulacral plate. Fig. 3—Peristomial plate. Fig. 4—Fenestrated peristomial plate. Fig. 5—Interambulacrum at the apex of the test. Fig. 6—Fourth plate from the apex on the left hand side of the same interambulacrum. Fig. 7—Interambulacral plates from the ambital region. Fig. 8—Interambulacrum at the peristome. (All measurements expressed in millimetres. Figs. 7–8 drawn to the same scale.) Abbreviations: BF, buccal tube-foot; BP, buccal ambulacral plate; G, gills: GC, gill cleft; G4, genital plate No 4; IR, interradius; L, lip; LPT, large primary tubercle; M, mouth; MT, miliary tubercle; NP, newly formed interambulacral plate; OP, ophicephalous pedicellaria; PF, pore-pair; PL, peristomial plate; PM, peristomial margin; PMB, peristomial inembrane; R, radius; SPT, small primary tubercle; STA, secondary tubercle of adradial series; STP, secondary tubercle of series between primary tubercles; T, tooth; TBP, tubeicles for pedicellariae; TF, trifoliate pedicellaria.
New interambulacral plates, like those of the ambulacra, are added immediately behind the apical system, in this case behind the genitals, in the angle between each genital plate and the ocular plates on either side of it. Each new interambulacral ossicle first appears as a very small trianguler plate only just visible to the naked eye (Text-fig. 2, Fig. 5, NP). A small tubercle, miliary in size, soon develops in the centre of the plate and grows rapidly to occupy nearly its whole area. It is asymmetrical in shape, corresponding to the triangular shape of the plate (IL). By the time a further new ossicle and its tubercle have appeared on the other side of the genital, two or three pedicellariae have been added near the adoral edge (IR). The plate begins to square up and, although the primary tubercle still takes up most of the area of the plate, further small tubercles and pedicellariae are added, this time on its aboral side. From now on there is very little addition to the adoral side (2L). Growth continues, especially aborally, so that the plate becomes almost rectangular with its longest axis parallel to the median suture line (2R). This is accompanied by rapid growth of the large primary tubercle (LPT) while a small primary tubercle (SPT) appears in the centre midline. Expansion of the plate adradially begins so that the large primary tubercle becomes sur rounded on either side and aborally by a ring of tubercles and pedicellariae. Adorally, the ring is completed by those present on the most apical part of the next plate (Text-fig. 2, Fig. 6). Adradial and admedial expansion continues rapidly so that the fifth or sixth plate down becomes elongate parallel with the ambitus and therefore at right-angles to the previous direction of elongation. Expansion of the primary tubercle evidently slows down so that at the ambitus the tubercle finally comes to take up rather less than a quarter of the whole plate. It does expand slightly, however, so that its areole comes to extend over the suture line on to the next most adoral plate, thus helping to hold the plates firmly together (Text-fig. 2, Fig. 7). The areole is also much more sharply delimited than it is in the more aboral plates, with a distinct ridge becoming developed around it. Evidently when Mortensen (1943) wrote, “In general the areoles round the larger tubercles are narrow and indistinct”, he was referring to the most aboral ones.
Past the ambitus, as the plates become more compacted, they become smaller once more so that the large primary tubercles take up correspondingly more of each plate, until right at the edge of the peristome they once again constitute almost the complete plate (Text-fig. 2. Fig. 8). Their areoles become contiguous, and secondary and miliary tubercles are reduced in number. The outer series of secondary tubercles persists, however, and becomes very regular. At the peristomial margin resorption is constantly causing plates to disappear The plates are made irregular by the development of deep gill clefts (GC) extending up as far as the third plate from the margin. In this way the two most adoral plates on either side become completely cut in half, and sometimes, due to resorption, the admedial portion with its primary tubercle will have disappeared while the adradial half still lingers on at the edge of the gill cleft (Text-fig. 2, Fig. 8, IR). The parts of the third and fourth plates immediately underlying the gills bear neither pedicellariae nor spines, and so are quite smooth in denuded specimens (PG).
Formation and growth of interambulacral plates in young specimens or “imagos” of Echinus miliaris have been described by Gordon (1926) and appear to be effected in very much the same way as I have described for the addition of new plates in older specimens of Evechinus chloroticus. In a small specimen (18 mm diameter) the sequence of plates was the same as in older specimens. The fifth plate down from the apex corresponded to the fifth plate of a larger specimen in being the first plate elongate parallel with the ambitus, but as there were only 15 interambulacral plates in all the fifth plate in this case was situated almost at the ambitus.
The interambulacra are described by Mortensen (1943) as becoming very constricted at the peristome and so narrower than the ambulacral areas. This is true,
for the plates above the gill clefts, but those surrounding them are actually caused to broaden out so that at the edge of the peristome the interambulacral areas are of the same size as or even slightly larger than the ambulacral areas.
Yonge (1949) has described a method for aging plates of Echinus esculentus and claims that “careful horizontal grinding of these reveals rings of growth”. The same technique was tried with interambulacral plates of Evechinus chloroticus but no distinct growth lines could be distinguished. The gut of the animal is deeply pigmented and specimens are often found with the inner wall of the test quite pink, but evidently the pigment cannot be laid down permanently. It was suggested by Dr. Fell (personal communication) that possibly the rings formed by the trabeculae in the spines might correspond to growth rings, for seven to eight such rings can be made out in a spine of Echinus esculentus, which is known to have a life span of eight or more years. However, there can be no such correlation in Evechinus chloroticus as the spines of very small specimens had the same number of rings as those of large specimens. On the interior of the test, however, at both admedial and adradial ends of each plate, a number of ridges can be seen which are obviously associated with growth. They are rather inegular, and as again specimens of quite different sixes may have the same number of ridges they are evidently not seasonal or annual phenomena.
The interambulacral plates of Evechinus appear to be of much the same pattern as those of Echinus, except that in the latter the plates immediately below the ambitus bear numbers of secondary tubercles, which have become so large that they are difficult to distinguish from the primary tubercles (Chadwick, 1900). Such plates appear to be carrying from 8 to 12 primary tubercles. The interambulacra of those echinometrids which are notable for their particularly long spines have become modified in a similar way, while those forms which live in very exposed situations have developed adoral petaloid ambulacra causing the interambulacral areas to be much more restricted than is the case in Evechinus chloroticus (Mortensen, 1943).
(Text-fig. 2, figs. 1–4.)
The peristome is that area of the animal which extends from the adoral edge of the calcareous plates of the corona to the mouth. Some authors (Lang, 1896) describe the corona and the peristome as together constituting the perisome. It is a tough fibrous membrane in which numerous calcareous plates are imbedded. At the oral edge it is terminated in a thick, circular lip (L) surrounding the projecting tips of the five teeth. In each radius immediately below the lips are the five pairs of buccal tube-feet (BF). These will be described in the section dealing with the ambulacial system. Each one is situated on a small buccal ambulacral plate (BP) roughly triangular in shape (15 × 25 mm) which is perforated by the excurrent and incurrent canals of the tube-feet. Around the edges of the plates numerous small tubercles (TBP) are scattered for the articulation of pedicellariae, which are mainly of the ophicephalous type (OP) although a few trifoliate (TF) may be present among them.
The remainder of the peristome is relatively bare. Small calcareous plates (Text-fig. 2, Fig. 3) are scattered here and there over it, particularly in the areas corresponding to the ambulacra of the corona. Each plate bears several tubercles for articulation with the stalks of trifoliate pedicellanae, which are very abundant in this area, although their smallness of size and delicacy of structure do not render them very obvious. No pedicellariae of any other kind are present. In addition, the peristome contains a large number of small fenestrated plates (Text-fig. 2, Fig. 4) imbedded within it. Spines, such as are present on the peristome of Echinus, are completely absent in Evechinus.
The peristome forms the floor of the lantern coelom and as such, in each interradius, is continued at its adoral edge, as a pair of branching outgrowths, or gills (Text-fig. 2, Fig. 1, G), described later in the section dealing with Aristotle's lantern and the lantern coelom. In repose the peristome lies quite flat, but when the lantern is protracted, the peristomial area becomes pushed out to assume a blunt conical shape. In these movements of the lantern, it is seen how necessary it is to have the area of the body immediately surrounding it completely flexible. If the mouth were surrounded by the hard, immovable plates covering the rest of the animal the lantern would be inoperable.
The diameter of the peristome increases with the size of the animal. In average size specimens it is usually between 20 to 25 mm in diameter, which is considered to be quite wide by Mortensen (1943), in comparison with other echinoids However, the peristome, expressed as a percentage of the horizontal diameter, decreases with age—e.g., in a specimen of 18 mm diameter it comprised 44% of the horizontal diameter, while in one of 98 mm diameter it comprised only 26%.
Some members of the Family Echinometridae—e.g., Zenocentrotus kellersi and species of Heterocentrotus—carry spines on the peristome in the same way as do species of Echinus (Mortensen, 1943). These are not present, however, in either Evechinus chloroticus or Heliocidarts erythrogramma The peristome of H. erythrogramma is very similar to that of Evechinus except that tridactyl pedrcellariae are also occasionally present scattered among the trifoliate. There are also fewer calcarcous plates. In width, comparative bareness of the buccal membrane, and the presence of delicate, fenestrated plates imbedded within it the peristome of Evechinus conforms to the general pattern exhibited by echinometrids.
(Text-fig. 1, Fig. 1.)
The aboral extremity of the test in all regular echinoids terminates in a number of plates which together are known as the apical system. This may consist of two things of plates, an outer ring of oculars, or radials and an inner ring of genitals, or basals, surrounding the circular periproct. Evechinus chloroticus, however, shows an intermediate stage between this dicyclic condition, which is typical of most of the Echinidae, including Echinus, and the monocyclic condition where the oculars have all been drawn into the inner ring and are included between the genitals in a single ring surrounding the periproct. In Evechinus oculars II, III and IV all remain outside—i.e., they are exsert, while oculars I and V have become insert.
The plates are sometimes given the name of “calyx” but MacBride (1906) objects to this term on the grounds that it has no homology with the structure of the same name found in crinoids. “Some zoologists have separated the ocular and genital plates under the name of ‘calyx’ from the rest of the corona, under a mistaken idea that they are homologous with the plates of the body or calyx of a Crinoid.”
The ocular plates (OC) are five small ossicles in each radius which bear the terminal tentacles of the ambulacral canals. The term “ocular” refers to the fact that these tentacles were once thought to be light-sensitive and to function as cyes. Each plate usually bears one large spine on the surface nearest to the periproct, with several other smaller ones, and also pedicellariae, scattered here and there. The outer border is grooved to dovetail into the double row of ambulacral plates abutting against it. Each edge is produced to form a sharp corner, which Mortensen (1943) describes as “rather characteristic”. Two of the ocular plates, oculars V and I, are typically included in the limitation of the periproct—i.e., they are insert—which is the common condition in the Echinometridae, although a few members of the family have all oculars exert—e.g., Echinometra vindis, E. insularis, Zeno-
centrotus paradoxus and Heterocentrotus mammillatus (Morténśen, 1943). There is some variation in E. chloroticus, however. I have found ocular IV insert in one specimen, and several others in which it was almost insert. Mortensen (1943) comments on this tendency for further ossicles to be drawn into the inner circle. “Jackson has found one specimen with Oc. I, V and IV insert, and I have found the same to be the case in one specimen of 34 mm diameter … in one case Jackson found Oc. IV instead of V insert.” The size of the plates varies slightly about the periproct of the same animal, but in a specimen of 77 mm diameter they varied from 2.5 mm to 3 mm in width, and 1.5 mm to 2 mm in length—i.e., 13% of the diameter of the apical system. The pore is of the order of 0.2 mm wide which Mortensen (1943) apparently regards as unusually small. However, in his figure of the apical system he has drawn no pores at all showing in the oculars, while in describing the preceding species, Selenchinus armatus, where the pores are of the same order of size as in Evechinus chloroticus, he describes them as being comparatively large; so there is evidently some mistake. Possibly the specimen of Evechinus used for the figure was not properly cleaned so that the ocular pores were not showing clearly. They are usually rounded but may be slit-like in some specimens.
The genital plates (G) lie in the five interradii and all abut against the periproct. They are larger than the oculars and like them vary in size. Generally those in interradu 4 and 5 are somewhat smaller than those in interradii 3 and 1, while that in interradius 2 is considerably enlarged to form the madreporite. In the specimen of 77 mm diameter, the genital in interradius 3 was 4 mm wide by 3.5 mm long—i.e., 31% of the diameter of the system. Each plate is roughly pentagonal in shape, the pointed end being directed away from the periproct. It bears the genital pore, which is quite large in both sexes (0.7 mm in the same specimen of 77 mm diameter) and so cannot be used for sex determination, as it is in some echinoids. In one specimen the pore of the genital was seen to have broken through the edge of the plate (Text-fig. 7, Fig. 5) after the same fashion as the pores in Zenocentrotus kellersi where it is the normal condition (Mortensen, 1943). There is usually one large spine at the inner edge of each plate, surrounded by several others of varying sizes. The tubercles of these, and particularly those of the large spines, have an asymmetrical boss and consequently areole, the edge lying next to the periproct having become quite flattened.
The genital plate in interradius 2, as previously mentioned, is enlarged to twice the size of the other genitals and has developed a porous structure to function as the sieve plate or madreporite (M) of the ambulacral system. In several specimens the madreporic surface was continued on to one or both of the neighbouring genital plates. (Text-fig. 1, Fig. 1, MS). In these cases the madreporic ampulla must also be enlarged to extend under the accessory genital plates. This tendency to increase the madreporic surface apparently occurs quite frequently in other members of the Echinoidea, although Mortensen (1943) does not record it from Evechinus, nor mention it as commonly occurring in the Echinometridae. The only echinometrid he mentions is Anthocidaris crassispina, in which the madreporic pores in one specimen were observed to spread over genital 3. Lang (1896) remarks of this condition, “The madreporite, through which water flows into the stone canal, is not necessarily exclusively connected with the right anterior basal (genital) plate. On the contrary, the neighbouring genital plates, indeed all the five plates, and in isolated cases even the neighbouring interradial plates of the corona may be perforated by the afferent ducts of the stone canal. In Palaeechinus each basal plate is perforated by three pores, which are perhaps apertures of the stone canal, perhaps genital apertures, or else partly the one and partly the other. In no case, however, do the madreporic apertures extend to the radials (ocular plates)”. The oculars in Evechinus also, were never found to have the madreporic surface continued on to them. The madreporite may also bear several small spines and a few pedicellariae outside the
porous areas. There are usually three spines grouped together at the inner edge of the plate and one is usually present on either side of the genital pore. A few may also be found scattered here and there among the pores. In one specimen as many as 16 were counted.
The periproct (PT) is circular to roughly elliptical in outline. In specimens from 60 to 98 mm in diameter it varied randomly from 5 mm to 7 mm in diameter and was never found wider than this even in the largest specimens. It consists of a tough membrane in which a number of plates are imbedded surrounding the slightly excentric anus. There are quite large spaces between the plates in older specimens, while in young specimens they fit closely together. There is an outer circle of large plates, within which lies a second circle of long, thin plates, sharply pointed proximally, which radiate out from the central anus. The suranal plate cannot usually be seen, although Mortensen (1943) claims to have seen it in “quite young specimens”. Small spines are present on the larger plates only, but pedicellariae may be present on the plates immediately surrounding the anus. More of the large outer plates are present on the periproct of very large specimens. Heliocidaris erythrogramma differs from Evechinus in this respect, that spines and pedicellariae are not so numerous on the plates of the periproct, and indeed on all the plates of the apical system.
Measurements taken of the apical system of Evechinus show it to be rather small. Mortensen (1943), from a sample of 20, found it to be 12% to 15% of the horizontal diameter, and from a sample of 42 I have also found this to be the general size range in average size specimens (60 mm to 90 mm diameter). In smaller specimens, the apical system takes up a correspondingly larger percentage of the horizontal diameter. One of 18 mm diameter had an apical system of 4 mm diameter—i.e., 22%—while Mortensen found a very small specimen of 6 mm diameter to have an apical system of 2 mm diameter—i.e., 33%. Conversely, the larger the specimen, the smaller percentage of the diameter does the apical system take up— e.g., it was 11% in an animal of 97 mm diameter.
(Text-fig. 3; 4, Fig. 8.)
The external surface of Evechinus chloroticus is covered with a thick carpet of green and white spines of varying sizes. Each spine consists of a slender shaft (SH), which in primary and the larger secondary spines is tapered to end in a blunt point, usually rather light in colour. Compared with other members of the Echinometridae, these spines of Evechinus, like those also of Selenchinus, Pachycentrotus and Caenocentrotus, are only of moderate size. In other echinometrids the spines are characteristically very long and well developed (Mortensen, 1943). The small secondary spines have brilliant white tips and are club-shaped, a very characteristic feature of the genus. The shaft has a ribbed appearance which is caused by the projecting ends of the calcareous wedges of which it is composed. These are revealed in cross section (Text-fig. 3, Figs. 4, 5). Neither the neck nor the collar regions are distinct in spines of Evechinus. Instead the shaft simply terminates in a conspicuous milled ring (MR), formed by the ribs expanding and curling over on themselves (Text-fig. 3, Figs. 1, 2 and 3). The base of each spine is smooth and rounded, ending proximally in a smooth socket, the acetabulum (AC), which fits over a corresponding tubercle (T) on the test. The tubercle is much larger in proportion to the acetabulum, and MacBride (1906) points out that this permits the spines of echmoids to have a very wide range of motion. It is supported on a prominent boss (B) from which it is delimited by a platform (PF), which in Evechinus, however, is distinct only on the larger tubercles. The spines are imperforate like those of all Echinometridae and also the Echinidae (Mortensen, 1943), so that there is no
Text-fig.. 3.—Spines and Spicules. Fig. 1—Large secondary spine. Fig. 2—Club-shaped secondary spine. Fig. 3—Base of primary spine. Fig. 4—T.S. primary spine. Fig. 5—T.S. club-shaped secondary spine. Fig. 6—L.S. secondary spine. Fig. 7—L.S. club-shaped secondary spine. Fig. 8—Spicule from a tube-foot. Fig. 9—Spicule from a buccal tube-foot. (All measurements expressed in millimetres.) Abbreviations: AC, acetabulum; AM, attachment marks of areolar muscles; BA, base; C, cortex; CH, club-shaped head; EP, end plate; MD, medulla; MR, milled ring; PF, perforation; PJ, projection; RZ, radial zone; SH, shaft; SP, septum; T, trabecula; TH, tapered head.
axial ligament present, with its accompanying perforations of tubercle and acetabulum.
The milled ring and the area of the base immediately below it provide attachment for the radiole or areolar muscles (Text-fig. 4, Fig. 8, ARM). The rest of the base supports elastic connective tissue fibres (CT) which maintain the spine in place. The other end of the areolar muscle is attached to the areole (AR) of the tubercle, while the elastic fibres are attached mainly to the boss. Cuénot (1948) describes these fibres as “muscle interne” as distinct from the areolar muscle or “muscle externe”, but in longitudinal section it is seen to be exactly similar to the elastic connective tissue ensheathing the tube-feet. This interpretation would be more in keeping with its function which is merely to hold the spine in place on the test while the areolar muscles alone effect movements. Also seen in longitudinal section is the epithelium (EP) covering the areolar muscle and extending a short way up the spine. In very young echinoids the whole spine is covered by external epithelium, but this dies off as the spine grows and the cortical region is developed. About halfway between the milled ring and the test a nerve ring (NR) passes around the spine, enclosed within the epithelium.
Transverse sections of spines (Text-fig. 3, Figs. 4 and 5) reveal a complex and beautiful pattern which is useful in systematic diagnoses. The centre of the spine consists of a sponge-like mass of calcite termed the medulla (MD), from which vertical septa (SP) of the same material radiate out. The septa are united together by rod-like trabeculae (T) passing between them. The septa and the trabecular wedges together constitute the radial zone (RZ), outside of which lies the thin cortex, in Evechinus made up of large end-plates (EP) continuous with the trabecular zones. It is these end plates of the cortex which are responsible for the ribbed appearance of the shaft. There is no sign of either cortical hairs or thorns.
The frequency of the trabeculae is greater in some parts of the radial zone than in others. In the transverse section figured (Text-fig. 3, Fig. 4) there are three main concentrations of trabeculae. The calcite is darker in these regions so that they are quite conspicuous. They may possibly correspond to growth rings, but this is doubtful as three such rings were found in the primary spines of three specimens of differing sizes, 19 mm, 55 mm, and 88 mm diameter respectively. In the smallest specimen, however, the number of trabeculae in the two inner rings was much fewer than in the specimens of larger diameter. The septa were also much narrower.
Transverse sections of the spines of Heliocidaris erythrogramma are very similar except that the rings of trabeculae are rather wider than in Evechinus. There is a marked colour difference, however; in those specimens which I was able to examine the radial zone was reddish brown, while the medulla was purple. Spines of adult Echinus have usually seven rings of trabeculae. As the age limit of this animal has been determined by other methods to be about seven years (Yonge, 1949), it is very tempting to regard the rings here as annual phenomena. The medulla is purple in colour with the inner part of the radial zone golden merging to green at the periphery. The cortical zone is much better developed than in Evechinus.
Longitudinal sections ground of primary and large secondary spines (Text-fig. 3, Fig. 6) show the central medulla beginning as a constricted area halfway up the base, broadening suddenly just above the milled ring and then tapering gently up the shaft to the top of the spine. The green radial zone is sharply delimited a short distance above the acetabulum in the midline, but at the sides it is not evident until immediately above the milled ring. The remainder of the base is quite colourless. The small secondary spines present the same basic pattern except that the medulla, instead of tapering to the tip, broadens out so that the head comes to consist principally of medulla (Text-fig. 3, Fig. 7). This would account for the brilliant white tips of these spines. The relatively large proportion of medulla is also revealed in cross sections (Text fig. 3, Fig. 5), where the radial zone is only just evident;
with the end-plates of the cortex visible outside it. Comparison of both transverse and longitudinal sections of tapered and club-shaped spines shows that the former could easily have grown from the latter by the addition of proportionally more calcite in the radial zone, so that ultimately in the primary spine it becomes of greater width than the medulla. It can be seen from the figures that the medulla is of approximately the same diameter in both kinds of spine; so it evidently does not increase appreciably after the club-shaped stage.
The distinction between the primary and secondary spines of Evechinus together with their corresponding tubercles appears to be rather subjective. The very largest spines, or primary spines, occur in a conspicuous, vertical row, down the centre of each column of interambulacral plates. (Text-fig. 2, Figs. 5–8, LPT). They vary in size according to their position on the test, being shorter aborally, increasing in length to almost double at the ambitus and then decreasing again as they approach the peristome. In a specimen of 98 mm diameter they varied 8 mm aboral, 16 mm ambitus, 11 mm adoral—i.e, 1:2:1.4. Mortensen (1943) describes the largest spines as rarely exceeding 15 mm in length, but most which I have seen are longer than this Specimens of 80 mm to 90 mm diameter usually had primary spines attaining about 20 mm at the ambitus. There is some individual variation, however. While a specimen of 98 mm diameter had primary spines 16 mm in length, one of only 50 mm diameter had them attaining 18 mm at the ambitus.
Primary spines are also present as a double vertical series in the interporiferous zones of each ambulacrum, immediately surrounding the poriferous zones (Text-fig. 1, figs. 2–3, SPT). Near the peristome they are often borne on every plate, but on the remainder of the test vary usually between every second to fourth plate, and may become even more widely separated near the apex. They are smaller and less variable in size than those of the interambulacral plates. In an animal of 97 mm diameter they varied 6 mm aboral, 10 mm ambitus, 9 mm adoral—i.e., 1:1.6:1.5.
A series of spines of similar size and vertical distribution is present in the interambulacra, admedial to the large primary ones (Text-fig. 2, figs. 5–8, SPT). Mortensen (1943) designates their tubercles as secondary. “In the interambulacra the larger secondary tubercles usually form a distinct vertical series admedially to each primary series…” As these tubercles are always well developed and quite as large as those which he describes as primary on the ambulacral plates, and the spines which they support are of the same order of size, I think they should also be described as primary. In that case there are two kinds of primary tubercle and spine, large (LPT) and small (SPT). The very large ones are only present in the interambulacra, while the small primary spines occur in both ambulacra and interambulacra, as described above.
In addition to the three sets of primary spines, the test is covered by numerous smaller spines of varying shape and size, all of which are designated secondary spines. These may be tapered or club-shaped, and may form distinct vertical series on the test in much the same way as the primary spines, which they may even approach in size in large animals (Text-fig. 2, Fig. 7). The series, however, are not as constant as those formed by the primaries In average-size specimens there are three rows of such secondary spines in each interambulacrum and one in each ambulacrum. In the interambulacra (Text-fig. 2, Figs. 5–8) there are usually: (1) Admedially a single vertical row which in large specimens may be double, some becoming almost as large at the ambitus as the small primary spines. In some specimens, especially young ones, they are represented only by club-shaped spines. This series is lacking in the specimen figured here. (2) Adradially, there is an irregular row (STA) which in some specimens may become an alternating double series with each plate bearing two tubercles. In large animals they are all pointed, although the most aboral and adoral ones are conspicuously white-tipped, and in small specimens are club-shaped. (3) Between the large and small series of primaries a series of
small secondaries may be seen alternating with them (STP). These also may be club-shaped at the two extremities of the test. In very large specimens, usually over 100 mm diameter, further irregular rows may be present, in between the admedial secondary spines, and also between them and the small primaries. In the ambulacra (Text-fig. 1, Figs. 2 and 3) there is radially a single irregular median series (STR), though as Mortensen (1943) says, there may be two distinct vertical series in larger forms. In addition, the poriferous zones of large specimens may bear secondary spines in vertical rows between the three horizontal sets of pore-pairs (STZ). In small and average size specimens these are all club-shaped Over all the remainder of the test small club-shaped secondary spines are scattered either at random or in rings surrounding the primary spines. They vary in length from 2 mm to about 6 mm. The club-shaped nature of many of these secondary spines is described by Mortensen (1943) as “very characteristic”.
In a specimen of 23 mm diameter only the interambulacral primaries and those of the ambulacra, except the most aboral and adoral, were pointed. All the rest were club-shaped. It seems that all the spines, including possibly even the largest primary ones, pass through a club-shaped stage during their period of growth. The three categories thus grade into one another extensively, but by correlating size, shape and position on the test it is possible to create some sort of classification useful for descriptive purposes.
The function of the spines is two-fold. They are important organs of defence against predators in which they are apparently very successful, for I have observed, as did Mortensen (1943), that “regenerated spines are only rarely seen, a consequence, probably, of the strength of the spines—but possibly also due to the absence of attacking animals”. When the animal is disturbed the aboral spines immediately surrounding the anus, which normally stand up vertically about it like a palisade, close down to cover it. The spines surrounding the peristome, the other vulnerable region of the body, also close down over it.
The spines help in the locomotion of the animal. They become the only organs of locomotion when the animal is moving over a loose, sandy surface. Over hard surfaces the tube-feet are often described as almost completely taking over this function. However, in an aquarium tank with a pebbly bottom, such as that on which the animal is frequently found, the spines were seen to assist the tube-feet considerably. The tube-feet, anterior with respect to the direction in which the animal was moving, were extended to take hold on fresh surfaces, while the “posterior” spines helped to propel the body, rather like oars, after them. As Mac-Bride (1906) suggests for Echinus esculentus, the spines are also used to steady the animal and prevent it from overturning under the unbalanced pull of the tube-feet.
(Text-fig. 4, figs. 1–4, V.)
Dissection. Trifoliate and ophicephalous pedicellariae are easily obtained from the peristome by scraping. Tridactyl pedicellariae are not so plentiful, but can be readily seen even with the naked eye, scattered here and there on the test, especially on the adoral surface. Gemmiform pedicellariae occur in very large numbers on the aboral surface of the animal. All four types of pedicellariae should be examined under a microscope to reveal the details of their structure.
Pedicellariae are found scattered over the whole test of Evechinus chloroticus. The four main kinds of pedicellariae typical of echinoids are all present. They are delicate, remarkably complex structures apparently derived from modified spines (Lang, 1896). Each consists of three parts: (1) The head (H), comprised of three jaws, or valves (V). In each of these a basal portion, or apophysis (A), with deep sockets (ADS) for the attachment of adductor muscles, and a distal blade (B), in
Text-fig. 4.—Pedicellariae, Sphaeridia and Spines. Fig. 1—Gemmiform pedicellaria. Fig. 2—Gemmiform pedicellaria, cleared and with mucous glands removed. Fig. 3—T. S. head of gemmiform pedicellaria at the level WX. Fig. 4—T. S. head of gemmiform pedicellaria at the level YZ. Figs. 5.–6—Sphaeridia removed from the test. Fig. 7—L. S. Sphaeridium. Fig. 8—L.S. miliary spine at its articulation with the test. (All measurements expressed in millimetres. Figs. 3–4 drawn to the same scale.) Abbreviations: AC, acetabulum; ADM, adductor muscle, AR, areole; ARM, areolar muscle; B, boss; BA, base; CSR, calcareous supporting rod; CT, connective tissue; EC, cushion of epithelium; EP, external epithelium; EPG, secretory epithelium of poison gland; H, head; ME, muscle envelope, MG, mucous gland; M, muscle layer; MR, milled ring; MT, mamelon of test; N, neck; NR, nerve ring; P, poison; PF, platform; PG, poison gland; PV, position of valve, S, stalk; T, tubercle; TC, tactile cushion; V, valve,
most cases toothed, may be distinguished. The adductor muscles (ADM) are large muscle bands passing between adjacent valves. The abductor muscles (ABM) are longitudinal fibres passing from ridges at the base of each valve to the calcareous supporting rod (CSR) of the stalk. The abductor muscles are seen to be a much less efficient mechanism than the adductors. (2) A flexible neck (N) consisting of longitudinal muscles and containing no calcareous ossicles. It is much reduced in the gemmiform pedicellariae. (3) A rigid stalk (S) consisting of what appears to be a firm calcareous rod but when sectioned is seen to be made up of calacareous strands disposed about an inner, non-calcareous core.
I. Trifoliate pedicellariae (Triphyllous) (Text-fig. 5, figs. 1–3). These are small pedicellariae, about 2 mm long, found in large numbers on the peristomial membrane and scattered between the spines all over the surface of the test in both ambulacral and interambulacral areas. The head is very small (0.1–0.2 mm) consisting almost entirely of three broad, blunt jaws which are untoothed. From the distal part of the apophysis several fragile digitate processes (DP) project. These are characteristic of Evechinus and described by Mortensen (1943) as “remarkable”. It is hard to imagine what function they might have. Shallow sockets for the attachment of the adductor muscles of the valves lie immediately below these processes. They are separated by a broad median ridge (MRA) which is grooved to provide a surface of attachment for the abductor muscles. The whole valve is covered with a cushion of ectoderm. The neck is very long and flexible (0.9 mm) while the stalk is of almost equal length, containing a thin calcareous rod which swells out to provide the proximal surface of attachment for the abductor muscles.
They are thought to function as cleaning organs, removing any small particles of mud and grit which may fall upon the animal. MacBride (1906), working on Echinus, describes the valves of this type of pedicellaria as being capable of independent action. Two blades work together, holding the object to be disposed of, while it is smashed by the third. The resulting fine powder may then be removed by the cilia of the epithelium. Such a function would, however, only be performed by those on the aboral surface of the test. The remaining trifoliate pedicellariae may deal with small animals or plants which chance to settle on the sea-urchin. In life they may be seen perpetually waving about from side to side.
II. Ophicephalous pedicellariae (Text-fig. 5, figs. 4–5). These are rather larger than the preceding type (2–3 mm), but, apart from a larger head (0.6 mm), have much the same proportions of neck (0.7 mm) and stalk (1 mm). They are called ophicephalous because the head, at the end of the sinuous neck, looks rather snake-like. The valves are broadly spoon-shaped with crenulate edges, the crenulations being continued down on to the central ridge dividing the two adductor muscle sockets. Immediately below these sockets three ridges run across the valve, ending on either side in small processes (AP) which articulate with similar processes on the other two valves (Text-fig. 5, Fig. 5). The ridges are for the attachment of the longitudinal muscles of the neck. At the base of each valve is an irregular hoop or hook (AH), each of which articulates with its fellow, making dislocation of the valves almost impossible. The pedicellariae are scattered sparsely over the entire test, being especially abundant about the mouth, where they arise in large clumps from the buccal plates supporting the buccal tube-feet (Text-fig. 2, Fig. 1). They are thought to assist in feeding, as their great abundance about the mouth would suggest. MacBride (1906) says of these in Echinus that “with their powerful bulldog grip (they) assist in holding small animals such as Crustacea till the tube-feet can reach them and convey them to the mouth”, and they probably perform the same function in Evechinus. They have no very characteristic features and so are disregarded by Mortensen (1943) as having little taxonomic significance.
III. Tridactyl pedicellariae (Tridentate) (Text-fig. 5, figs. 6–8). As stated by Mortensen (1943), there are two kinds of this type of pedicellaria. (1) Small
Text-fig. 5.—Pedicellariae. Fig. 1—Trifoliate pedicellaria. Fig. 2—Inside view of valve of trifoliate pedicellaria. Fig. 3—Lateral view of valve of trifoliate pedicellaria. Fig. 4—Ophicephalous pedicellaria. Fig. 5—Inside view of valve of ophicephalous pedicellaria. Fig. 6—Tridactyl pedicellaria. Fig. 7—Inside view of valve of tridactyl pedicellaria. Fig. 8—Small type of tridactyl pedicellaria. Fig. 9—Inside view of valve of gemmiform pedicellaria. (All measurements expressed in millimetres. Figs. 2–3 drawn to the same scale.) Abbreviations: A, apophysis, ABG, groove for abductor muscles; ABM, abductor muscles; ADM, adductor muscles; ADS, socket for adductor muscles; AH, articulating hook; AP, articulating process, B, blade; CSR, calcareous supporting rod; DP, digitate process; EP, epithelium; ET, end tooth; GP, groove for duct from poison gland; H, head; LT, lateral tooth; LW, lateral wing; MRA, median ridge of apophysis; MRB, median ridge of blade; N, neck; S, stalk; V, valve.
tridactyl pedicellariae (Text-fig. 5, Fig. 8) which to the naked eye are indistinguishable from trifoliate pedicellariae. The valves are 0.2 mm to 0.3 mm long and meet throughout, thus at first sight appearing rather like small ophicephalous pedicellaria, from which they are soon distinguished, however, by their lack of basal hooks. The neck is very long and flexible (0.5 mm) and the stalk, with its club-shaped calcareous rod, of almost equal length. They are found mainly with the trifoliate pedicellariae on the peristome. (2) Large tridactyl pedicellariae (Text-fig. 5, figs. 6–7), which are 4 mm to 5 mm long and so may be readily detected on the test, where they occur mainly on the adoral surface. The head, as Mortensen (1943) observed, is very large, usually about 2 mm long, while the neck and stalk are both of the order of 1 mm in length. The blade of the valve is usually twice as long as the base and rather slender, about 0.3 mm wide. The valve is, however, quite thick, especially near the base. On the outer surface a low median ridge (MRB) is present. The three blades meet each other distally and here their edges are coarsely dentate. On the inner surface a high median ridge (MRA) separates the two deep sockets which provide attachment for the adductor muscles. Grooves for the abductor muscles and lateral articulating processes (AP) are also present. Mortensen (1943) claims to have seen all transitions between the large and small forms. However, I have not been able to find any such transitional forms, although in the large type there are some variations in shape. The valves are usually long and slender, but some have been found that are quite broad and almost spoon-shaped. The tridactyl pedicellariae probably assist in feeding, passing small animals to the tube-feet and thence to the mouth. Also, as MacBride (1906) suggests, this type of pedicellaria may “seize and destroy the minute swimming larvae of various sessile parasitic animals, which would otherwise settle on the delicate exposed ectoderm of the sea-urchin”.
IV. Gemmiform pedicellariae. (Globiferous) (Text-fig. 4, figs. 1–4). These are important taxonomically as they are used to differentiate between the families of the Sub-order Echinina (Mortensen, 1943). In Evechinus they are quite conspicuous because of their large size and great abundance on the aboral surface of the test. The external epithelium covering them imparts a dark red coloration which fades, however, on preservation. The valves are quite small (0.6 mm), consisting of a long narrow blade terminating in a sharply pointed inoculating end-tooth (ET) and a rather smaller, lateral unpaired one (LT). The possession of this lateral, unpaired tooth is the most important taxonomic character of the Family Echino-metridae. In Echinus the lateral teeth are more numerous and always paired (Mortensen, 1943). The sockets for the adductor muscles are very deep and divided by a high median ridge (MRA). They extend out on either side in the form of characteristic lateral wings (LW). Articulating processes (AP) and grooves for the attachment of the abductor muscles (ABG) are also present. Mortensen (1943) describes these muscles as being much longer in Evechinus than is usually the case in the sub-order Echinina. In this, he points out, Evechinus resembles Loxechinus albus, a specialized member of the Sub-family Parechininae, Family Echinidae, and is also superficially similar to the genus Strongylocentrotus, where the neck is, however, capable of much greater movement, and on sectioning is seen to be more specialized in the possession of circular muscle lying inside the longitudinal fibres. As a rule, in both Families Echinidae and Echinometridae, there is no neck, the head resting instead directly on the upper end of the stalk. This is the condition in Echinus (Mortensen, 1943). Associated with each valve is a pair of poison glands (PG) lying above the valve to almost obscure it, and extending down to the supporting rod so that the neck is also hidden. In this matter I find Mortensen's (1943) figure difficult to understand, for he has drawn the glands as shorter than the valves, thus revealing the base of the valves and the entire neck. This gives the head of the pedicellaria a globular shape, whereas. in all specimens I have observed, it is quite pear-shaped. That the gland is paired confirms the position of Evechinus
in the Echinometridae, for it is single in both the Echinidae and the Strongylo-centrotidae (Mortensen, 1943). A short common duct leads from the glands at the top of the head, near the end-tooth. Mortensen (1943) says, “the poison glands are not very large, but a thick investing skin makes the head of these pedicellariae rather thick and clumsy”. This observation is not based on sectioned material, but merely on external appearance. In sections which I have cut the epithelium (EP) is seen to be quite thick, but the glands are also large, occupying most of the volume of the head. Each gland is surrounded by a layer of longitudinal muscle (MM), internal to which is a cuboidal epithelium (EPG) for elaboration of the poison. Mortensen found it difficult to ascertain whether the mucous glands (MG) were present or not. I found these relatively easy to distinguish in preserved specimens, lying halfway up the head, between each pair of poison glands. They are a lighter colour than the poison glands and have a translucent appearance. In sections stained with Ehrlich's haematoxylin they take on a dark purple colour. A sensory, or tactile, cushion (TC) is present on the inner surface of each valve, just above the adductor muscles.
Most authors agree that the gemmiform pedicellariae of echinoids are used for defence, particularly against starfish. This would agree with their distribution on Evechinus, for they are limited to the aboral half of the test. Apparently the stimulus is first chemotactic, which causes the valves to open wide. When the enemy draws close and the tactile cushions are touched this second stimulus causes the blades to close violently. The wounding of the enemy then renews and intensifies the chemical stimulus (MacBride, 1906). Cuénot (1948) points out that the pedicellariae never seize other parts of their own body such as tube-feet or spines, and never attack any of the commensal animals living on the test.
(Text-fig. 4, Figs. 5–7.)
Dissection. The sphaeridia are very small and difficult to detect. They may be seen, however, by scraping carefully with a scalpel along the centre of an ambulacrum, at the same time examining the area with a hand lens under strong light. The small tubercles with which they articulate on the test may also be seen by examining a denuded test along the midline of an ambulacrum near the peristome with a hand lens.
Sphaeridia were first discovered by Lovén and have since been found present in all members of the Echinoidea except the cidarids. They are quite numerous in the Echinometridae but lack any distinctive characters, as is indeed the case in all families of the Sub-order Echinina, and so are of no taxonomic importance (Mortensen, 1943). They are present in the midline of each ambulacrum, especially near the peristome.
Each sphaeridium in Evechinus consists of a head and a stalk. The stalk (S) is of dense calcite bearing green pigment. In longitudinal sections (Text-fig. 4, Fig. 7) it is seen to have a lattice-like structure, very much like that of the plates of the test. At its proximal end it is slightly hollowed to articulate with a small tubercle on the test, while distally it is continuous with the head of the sphaeridium. Its sides provide attachment for the muscle envelope (ME) which surrounds the base of the sphaeridium and effects its movements.
The head (H) of the sphaeridium is usually unpigmented and rather refringent. Sometimes it is smoothly rounded (Text-fig. 4, Fig. 5), but it may be extended by an irregular distal projection (Text-fig. 4, Fig. 6). Microscopically it is described by Lang (1896) as being concentrically laminated in all echinoids, and Chadwick (1900) figures this condition for Echinus. In Evechinus a lamination shows in transverse sections of the head as it lies along the surface of the test, but in strictly longitudinal
Text-fig. 6.—Internal Anatomy. Adoral View with Lantern Removed. Abbreviations: AR, aboral ring; ADG, adoral part of gonad; AO, axial organ, AP, ampulla; APG, apical coalescence of gonad; CL, collateral canal; CLB, branches to collateral canal; D. diverticulum; EMC, external; marginal canal; FLI, first downward loop of intestine; FLS, first loop of stomach; GD, gonoduct; IMC, internal marginal canal; INT, intestine; ML, mesenteric ligaments; OE, oesophagus; R, rectum; RAC, radial ambulacral canal; SI, siphon; ST, stomach; ULI, upward loop of intestine.
tudinal sections (Text-fig. 4, Fig. 7) this is not evident. However, as Lang points out, it shows no “lattice-like perforated structure” like the rest of the skeleton and for that reason he thinks it may possibly correspond to the cortical layer of the spines.
A circular ganglion (NR) passes round the base of the sphaeridium and the whole structure is completely covered by a ciliated epidermis (EP) continuous with that covering the exterior of the test. The complete sphaeridium is only of the order of 1 to 1.5 mm high. At its base the epidermis is raised in a small cushion (EC) and here the cilia are said to be especially long. I was not able to demonstrate this in Evechinus, but as I have found the detection of cilia difficult in most parts of the animal I would hesitate to say that they were not present.
The sphaeridia are thought to be modified spines (Lang, 1896) which function as sensory organs, probably indicating to the animal its position with regard to gravity. As the animal shifts its position the heavy head of the sphaeridium would come to lie on different parts of the epidermal cushion, which is in turn closely associated with the nerve ring. In some echinoids—e.g., Clypeaster—the sphaeridia lie in completely closed cavities and thus come to resemble the statocysts of other phyla (Cuénot, 1948). However, such a “balancing” function has not yet been positively demonstrated for the sphaeridia of echinoids, although in experiments quoted by Cuénot (1948) it seemed that animals with their sphaeridia removed
took longer to return to the normal position than urchins with the normal complement of sphaeridia, which had been similarly displaced.
Dissection. The relationships of the ossicles comprising the lantern are easily studied on the lantern in situ. For more detailed study of individual ossicles a lantern deprived of its muscles, by cleaning in potassium hydroxide, is necessary.
The mouth lies within the peristome (Text-fig. 7, Fig. 6, P) in the centre of the adoral face and is directed downwards. From it the pharynx (PH) leads vertically upwards, enclosed within Aristotle's lantern. This is a complex assemblage of ossicles and muscles used mainly for feeding, but with the subsidiary function of respiration.
The lantern consists of 35 pieces, 30 of which are used for mastication. The largest and most prominent of these are the five sturdy pairs of jaws, each pair of which fuses in an interradius to form an alveolus (AL). These have the form of hollow, triangular pyramids (Text-fig. 7, Figs. 1–2), the inner cavities of which are traversed by the slender, more fragile teeth (T). The two lateral faces of the alveolus are marked with fine transverse, slightly sinuous grooves (Text-fig. 7, Fig. 2, GLW) for the attachment of the radical muscles connecting neighbouring alveoli. These grooves are continued beyond the inner edge of the alveolus, thus presenting a toothed appearance. The outer face of the alveolus (Text-fig. 7, Fig. 1) is smooth and slightly convex, the suture (ALS) between the two constituent jaws showing clearly in an exactly interradial position. This external wall is incomplete aborally, being perforated by a large triangular foramen, the foramen externum, or foramen magnum as it is sometimes called (FE). The aperture through which the tooth projects at the top of the alveolus is known as the foramen basale (FB). It is separated from the foramen externum by the arch formed by the fusion of a pair of ossicles, the epiphyses.
The epiphyses (E) bear two small styloid processes (SP) which lie against the teeth, like the sides of a groove. A toothed epiphyseal crest (EC) runs distally from each process to the line of fusion of the epiphysis from each side (Text-fig. 7, Fig. 7). It appears to be purely ornamental. The arched outer surfaces of the epiphyses provide attachment for the protractor muscles of the lantern.
The internal cavity of each alveolus is occupied by a tooth, which projects from it adorally as the externally visible tooth, and aborally as the soft, slightly coiled root (RT). This soft root is enclosed within a pocket-like projection of the transparent roof of the lantern coelom, known as a dental pocket. The root of the tooth is a region of continuous growth, which is described by Cuénot (1948) as being effected by the fusion along the midline of two lamellae to form a hollow cone. The compaction and hardening of the tooth is caused by successive hollow cones piling up on each other and fusing. The calcareous part of the tooth is curved so that its convex side fits into a groove on the concave inner surface of the alveolus. The concave side of the tooth bears a flattened keel, or carina.
The rotulae (Text-fig. 7, Figs. 4, 6, 7, R) are five, more or less flat, rectangular ossicles lying radially between adjacent alveoli, looking rather like the spokes of a wheel. Slight grooves are present on the lateral faces of the alveoli where the rotulae articulate with them. Their main function appears to be support, both for the overlying compasses, and to help unite the alveoli. They also provide aboral attachment for the five radial pairs of ligaments which pass up the sides of the pharynx.
Lying on top of the rotulae, and therefore also in a radial position, are five delicately shaped ossicles, known as compasses (Text-fig. 7, Figs. 6, 7, C). These have nothing to do with the feeding function of the lantern, but are concerned
Text-fig. 7.—Aristotle's Lantern. Fig. 1—Outer surface of alveolus. Fig. 2—Inner surface of alveolus. Fig. 3—1.S. alveolus. Fig. 4—Rotula. Fig. 5—Axial surface of auricula. Fig. 6—Lantern after removal of two alveoli to show pharynx. Fig. 7—Aristotle's lantern in situ. (All figures drawn to the same scale.) Abbreviations: AA, ambulacral apophysis; AL, alveolus; ALS, alveolar suture AO, axial organ; AP, ampulla; AR, ambulacral ring; AU, auricula; AX, axial end; C, compass; CA, carina; CDM, compass depressor muscle; CEM, compass elevator muscle; E, epiphysis; FB, foremen basale; FE, foramen externum; FR, facts for rotula; G, gills; GC, gill cleft; GLW, grooved lateral wall of alveolus; GRM, groove for retractor muscles; IA, interambulacral apophysis; IM, intermediate muscle; L, lips, LC, lantern coelom; LL, long ligament of pharynx; MES, mesentery; OE, oesophagus; OHC, oesophageal haemal canal; P, peristome; PH, pharynx; PM, protractor muscle; PV, Polian vesicle; R, rotula; RAC, radial ambulacral canal; RM, retractor muscle; RR, radial ridge of pharynx; RT, root of tooth; SC, stone canal; SL, short ligament of pharynx; SP, stylord process; T, tooth.
instead with respiration. They are slender, curved structures, with their distal extremities bifurcate, and slightly projecting over the edge of the lantern. About halfway along their length they are thickened and grooved to provide attachment for the compass elevator muscles.
There appears to be some confusion in terminology in the literature where the rotulae and compasses are concerned. Lang (1896), for example, describes the rotulae as “sickles” or “falces”, while he reserves the term “rotulae” for what are now known as “compasses” with the term “radius” as an alternative. Chadwick (1900), on the other hand, while denoting the rotulae as such, describes the compasses as “radii”, which usage is now generally employed. Bather (1900) uses the term “brace” instead of rotula.
The perignathic girdle (Text-fig. 7, Fig. 5) must also be described in conjunction with the lantern, for the two are physiologically closely connected, the girdle being present only in those sea urchins which also have a lantern. It consists of ambulacral and interambulacral plates from the margin of the peristome, which have been bent inwards to form processes known as apophyses to which the main muscles of the lantern are attached. The ambulacral apophyses (AA) are large ossicles about 1 cm high, arising from the peristomial margin on either side of the ambulacral suture. They incline together so that their free ends unite to form an arch over each radial canal of the ambulacral system and its associated vessels. There are thus five of these arches, or auriculae, in radial positions surrounding the lantern and providing attachment for the five pairs of large retractor muscles. The interambulacral apophyses (IA) are not so well developed. They project about 5 mm into the body cavity as a continuous ridge uniting neighbouring auriculae. Their inner or axial surface is grooved for the attachment of the protractor muscles of the lantern. They also bear gill clefts (GC).
Three sets of muscles (Fig. 7) are involved in the feeding movements of the lantern. The most obvious are the five pairs of large protractor muscles (PM) running from the epiphysis on each side of the arch of the jaw to the interambulacral apophyses. These protrude the lantern through the peristome, at the same time tipping the alveoli back and bringing the teeth together. They therefore also function as jaw adductor muscles. Indeed in the earlier lierature (Lang, 1896; Chadwick, 1900) this is described as their only function. They are counteracted by a second set of large muscles, the retractor muscles (RM), which also act as abductors. They run horizontally from each side of the auriculae to well defined grooves on either side of the outer face of the alveolus. Their contraction withdraws the lantern into the body, and at the same time draws the teeth apart, opening the mouth. The intermediate, or radial muscles, are not so easily observed as they lie between neighbouring alveoli, attached to the sinuous grooves running along the lateral faces of each alveolus. Once the lantern has been protruded, it is made to move spirally to the left and to the right by their contraction.
The two remaining sets of muscles operate the compass ossicles in respiratory movements. The pentagonal ring of muscles connecting neighbouring compasses as they lie on the base of the lantern, function as compass elevators (CEM). The raising of the compasses also raises the thin membranous roof of the lantern coelom, within which the lantern is enclosed. This reduces the pressure in the lantern coelom and causes the gills, which are feathery extensions of the peristome, to be withdrawn. Running distally from the bifurcate tips of each compass to the interambulacral region of the perignathic ring, are the fine compass depressor muscles (CDM). Their contraction lowers the compasses and thus the roof of the lantern coelom, increasing the pressure and causing the gills to be everted. The oxygen thus taken into the lantern coelom is able to diffuse through its extremely thin, transparent walls into the cavity of the main coelom. The dental pockets about the teeth must increase the surface area for gaseous exchange with the coelom in much the same
way as the gills do with sea water. Although this complex mechanism has been evolved for respiration, it is generally considered, however, that the major part of the respiratory function is carried out by the tube-feet.
It may be seen from the foregoing description that Aristotle's lantern in Evechinus adheres to the general plan exhibited by the gnathostomous Echinoidea. In shape and disposition of both ossicles and muscles it closely resembles Echinus and like it possesses a camarodont type of dentition (Mortensen, 1943) by virtue of the epiphyses fused to form an epiphyseal arch, and by the carinated teeth. In Echinus and all echinids there are no supporting processes for the teeth such as the epiphyses bear in Evechinus, Heliocidaris erythrogramma and other echinometrids (Mortensen, 1943). The styloid processes of H. erythrogramma, however, are not so strongly developed as those of Evechinus. The auriculae of Echinus and Evechinus are apparently quite similar, being fairly broad, with a broad area of fusion between the apophyses. In average sized specimens of Evechinus this extends over approximately 4 mm, while in H. erythrogramma it is much narrower, being less than 1 mm in a specimen of 75 mm diameter. It would possibly be wider in larger specimens, which may attain 100 mm diameter.
(Text-fig. 6; 7, Figs. 6;8;9; 10.)
Dissection. The dissection to show the alimentary canal of Evechinus is made difficult by the large size of the gonads, which tend to obscure the other contents of the body cavity, and also by the extreme thinness of the gut wall Strong mesenteric ligaments attach the intestine to the gonads very firmly and must be previously cut if the intestine is lifted or moved in any way. If they are not cut, the intestine wall gives way and its mass of contents spills out to obscure the dissection.
The great convolution of the alimentary canal, particularly the intestine, makes its course rather difficult to follow. For general laboratory dissection, where only one animal is available with which to demonstrate all systems, it is best to dissect from the adoral surface. By cutting the test around the peristome with old scissors or forceps, the lantern is completely freed and gently tipped so that the stone canal and axial organ may be located and freed. The mesentery holding the oesophagus in place must also be cut. The whole lantern can then be lifted out of the body cavity and placed to one side, while still retaining its connection with the oesophagus (Text-fig. 6). To demonstrate the alimentary canal alone, however, I have found the best method to be that of removing the aboral half of the test piece by piece with strong forceps, leaving until last that part immediately surrounding the apical system. The rectum, stone canal and gonoducts are then carefully severed immediately below the apex. The aboral halves of the gonads must be then removed to reveal the large intestine coiled around the test in undulating dorso-ventral folds. In the five radii the narrower dorso-ventral loops of the stomach may be observed. The oesophagus and rectum may be seen situated in radius III thus giving a reference point for correct orientation (Text-fig. 8). To observe the whole course of the stomach and its attendant siphon, the intestine and the rest of the gonads must be removed (Text-fig. 9). Spilling of the contents of the intestine is unavoidable at this stage but they may soon be removed by gentle washing. Aristotle's lantern must be opened to observe the pharynx. This is best done by removing, with forceps or old scissors, a whole alveolus, and then one jaw from either side of it, at the same time clearing away the accompanying muscles.
The pharynx (PH) is that part of the digestive tube which is enclosed within the lantern (Text-Fig. 7, Fig. 6). It has a diameter of the order of 7 mm and a length corresponding to the height of the lantern—i.e., about 20 mm. Five radial ridges (RR) of connective tissue pass down its sides giving it a pentagonal shape.
About the mouth they become expanded to form five lobes, alternating with the interradial teeth. On both sides of each ridge are a pair of ligaments (LL) the adoral ends of which are fixed to the internal parts of the jaws. Aborally they are attached to the rotulae. Five other shorter pairs (SL) come from the inferior part of the pharynx to pass on to the jaws quite near the teeth.
The pharynx leads into the narrow, much convoluted oesophagus (OE) (diameter ca. 5 mm), which continues upwards along the vertical axis of the animal, together with the axial organ (AO) and stone canal (SC), almost reaching the periproctal region. From there it bends on itself and redescends to the level of the lantern, to pass out horizontally in radius III between the rectum and the first loop of the intestine to meet the wider, thin-walled stomach (ST). Sheets of mesentery unite the oesophagus to the axial organ and to the diverticulum of the stomach. The mesentery is also attached to the test in the apical region, thus suspending the oesophagus with the axial organ and attendant stone canal in the central axis of the animal. In some specimens the oesophagus has a striated appearance due to the presence of rows of pigment passing along it.
The stomach (ST) in fresh specimens is a yellowish-orange colour, and is extensively sacculated. It has been variously described as the “first or inferior spiral” (Lang, 1896; Bonnet, 1925), “direct canal” (Delage and Hérouard, 1903;
Text-fig. 8.—Alimentary System. Aboral View with Aboral Gonad Removed. Abbreviations: AO, axial organ: AP, ampulla; D, diverticulum; FLI, first loop of intestine; FLS, first loop of stomach; G, gonad; INT, intestine; L, lantein: ML, mesenteric ligaments; OE, oesophagus; R, rectum; RAC, radial ambulacral canal; ST, stomach.
Bonnet, 1925), or “first curve of the intestine” (Cuénot, 1948). It continues horizontally in an anticlockwise direction (viewing the animal from the aboral pole) forming a dorso-ventral inflexion in each radius, to lead into the intestine (INT), without any sharp boundary, in interradius 2. This is contrary to the condition in Echinus, as described by Delage and Hérouard (1903), where the slight inflexions of the stomach are interradial. The condition in Evechinus is more similar to that described by Bonnet (1925) for Spharechinus and Paracentrotus, where the internal border of the stomach has a pentagonal aspect while the external border forms a five-rayed star the arms of which ascend in the radial zones along the walls of the test. The stomach of Heliocidaris erythrogramma also has this aspect and is of comparable diameter with that of Evechinus. In the interradial zones the gut is suspended in such a way that the external border falls to the interior of the internal border, held in place by strands of mesentery (ML) securing it to the perignathic girdle. The diameter of the stomach is of the order of 9 mm.
At the junction of the stomach and the oesophagus is a sac-like dilatation, the diverticulum (D), which is said (Cuénot, 1948) to contain a feebly acidic liquid with a diastasic action on albumen and starch. He considers it the principal seat of absorption of the products of digestion.
The end of the oesophagus and the beginning of the intestine are connected by a narrow, cilia-lined tube and with a diameter of between 1 and 2 mm. This is the siphon (SI), or accessory intestine. It lies on the inner side of the stomach and accompanies this organ through all its turns, to finally open into it once more at the base of the inflexion in radius II. It is attached to the stomach by a narrow strand of mesentery, while a further strand links the internal marginal canal (IMC) of the haemal system to its inner side. There is no sign of an accessory siphonal groove such as is found in Arbacia (Cuénot, 1948). Its function has been thought in the past to be the subservence of respiration, which it effects by keeping a stream of fresh water flowing through the gut, thus functioning in much the same way as the accessory intestine of certain worms. (Lang, 1896; Chadwick, 1900; MacBride, 1906). However, Bonnet (1925) has suggested that the siphon serves as a diversion channel for water taken in with the food, passing the water directly to the intestine in which the excrements accumulate, and thus permitting the concentration of diastases in the stomach. This view is supported by Cuénot (1948). It may be that the siphon fulfils both these functions. The internal epithelium of the siphon is well developed and thrown into numerous folds, so that, as Bonnet (1925), suggests “… on ne peut s'empecher de penser que cet organ ne joue pas seulement le rôle d'un conduit servant à laisser passer l'eau extérieure dans la seconde courbure de l'intestine, mais qu'il pourrait bien remplir aussi quelque autre fonction”. He gives, however, no suggestions as to what that function might be.
The intestine (INT) is of larger diameter than the stomach (about 14 mm), but like the stomach, has very thin walls, which in fresh specimens appeal a pinkish-brown colour, in some places quite transparent. On the border between interradius 2 and radius III it turns upwards to return in the opposite direction to that of the stomach (i. e., clockwise, viewing the animal from the aboral pole). This inflexion, and the downward inflexion of the intestine in interradius 2, are held together by a continuous sheet of darkly pigmented mesentery which is continued along the whole internal border of the intestine. The intestine is even more convoluted than the stomach, being reflected down towards the lantern in each interradius, and upwards, overlying the corresponding loop of the stomach, in each radius (Text-fig. 8). This is in contrast to the condition in Echinus where, as described by MacBride (1906), the festoons of the intestine alternate with those of the stomach. In Heliocidaris erythrogramma the intestine follows the same course as in Evechinus but is of rather less diameter. Various names have also been applied to the intestine. Lang (1896) calls it the “superior spiral”, Delage and Hérouard
Text-fig. 9.—Alimentary System. Aboral View of Stomach with Intestine and Gonads Removed. Abbreviations: AP, ampulla; AU, auricula; D, diverticulum; FLI, first loop of intestine; FLS, first loop of stomach; IA, interambulacrum; IMC, internal marginal canal; L, lantern; ML, mesenteric ligament; OE, oesophagus; RAC, radial ambulacral canal; RLS, radial loop of stomach; SI, siphon.
(1903) the “reflected canal”, Bonnet (1925) the “recurrent coil” and “dorsal or second flexure,” and Cuénot (1948) the “second curve of the intestine”.
Arriving at the lateral border of radius III with interradius 3, the intestine is continued without any sharp boundary as the narrower rectum (R). This passes up between the previously mentioned radius and interradius, with gradually decreasing diameter, to the anus, which opens to the exterior from a variable position, usually a little excentric, within the periproct.
A continuous sheet of mesentery runs along the entire internal border of the gut, becoming especially well developed and darkly pigmented along the intestine. On the external border the mesentery is represented by strong mesenteric ligaments (ML) which firmly attach the stomach to the perignathic girdle, the intestine to the overlying gonads, and both coils of the gut to the sides of the test.
In all specimens examined the stomach has contained only a very small quantity of food materials in the process of digestion, while the intestine has always been more or less crammed with excrement in the form of small pellets. Many of the pellets appeared to be surrounded by a case of hyaline material, probably mucin. Lumps of this material were found at the beginning of the intestine in some specimens. It is probable that the internal epithelium cells in this region are specially concerned with the secretion of this material.
The first turn of the alimentary canal is thought (Cuénot, 1948) to correspond to the larval intestine, while the second turn is the result of progressive elongation of the larval rectum.
Food of Evechinus chloroticus
The great volume of the gut contents and the efficiency of the teeth in tearing and grinding food into small pieces, or fine powder in the case of hard objects, makes identification of such material difficult. However, animals have frequently been found holding pieces of the brown seaweed, Carpophyllum maschalocarpum, between their teeth, and all alimentary canals examined contained a large volume of such shredded brown alga, frequently together with green and red algae. The gut also contains much calcareous material, finely powdered and held together in the form of small balls. This would come from the shells of encrusting animals living on the seaweed and possibly also from animals such as tuberculous polychaetes encrusted on stones and rocks. In general it may be said that Evechinus chloroticus feeds on littoral seaweeds and their associated epifauna. One animal was found with a partially eaten leaf in its mouth of Coprosma repens, the common coastal “taupata”, the leaves of which are frequently found floating in the sea near the coast. This is interesting when taken together with Fell's (1952) account of ophiuroids, Pectinura maculata, in Dusky Sound feeding on pollen dropping from beeches (Nothofagus) overhanging the water. The only other record of such a nature is one he cites of a deep sea echinoid in the East Indies which feeds on the leaves of dicotyledonous trees washed out to sea by rivers. The fact that the exclusively marine echinoderms are able to feed on land angiosperms seems rather remarkable. In the case of Evechinus, however, such feeding is probably accidental, for in general the animal appears to exhibit little power of selection, eating almost anything edible with which it comes in contact. In the gut of one animal I found several small pieces of wood and in another a short length of string.
Histology of the alimentary canal (Text-fig. 10, figs. 1–5)
The digestive tube of Evechinus chloroticus consists of the four fundamental layers typical of all echinoids; the external or coelomic epithelium, a muscle layer, a layer of connective tissue, and an internal epithelium.
The pharynx (Text-fig. 10, Fig. 1) is covered externally by a low ciliated epithelium (LEP) which is not continuous with the coelomic epithelium covering the rest of the gut, but forms the internal lining of the lantern coelom. It consists of small cells with conspicuous nuclei. Internal to this is a thin muscle layer of circular fibres (CM). This thin layer is in contrast to the description of Echinus by Bather (1900), where the pharynx is described as being a muscular organ. The connective tissue of the pharynx is very well developed. It appears to form two layers, one within the circular muscle and one outside it. The external layer is confined to the radii, where it forms five pronounced radial ridges (RR). It is to these ridges that the ligament bands uniting the pharynx to the jaws are attached. The connective tissue lying inside the muscle layer is present only in the interradii where it takes the form of five shallow triangles (ICT), the apices of which are directed internally. Bounding the lumen of the pharynx is a high, extensively folded, pseudo-stratified epithelium (IEP) containing numerous gland cells secreting mucin (MU). These are especially abundant in the five radii, in each of which the epithelium forms a deep fold. A thin cuticle (CU) invests the internal edge. Also observed in transverse sections of the pharynx are the five radial vessels (RHV) of the haemal system, running down the outside of each radial ridge. The cross section of the pharynx of Evechinus has a very different form from that of Echinus as figured by Chadwick (1900), where the outline is distinctly five-rayed and where there appear to be no radial ridges.
The external epithelium (CEP) investing the oesophagu (Text-fig. 10, Figs. 2 and 3) is part of the coelomic epithelium covering the remainder of the alimentary canal which is also continued on the internal face of the test and is reflected on all the organs contained within the general body cavity. The cells appear similar
Text-fig. 10.—Histology of the Alimentary Canal. Fig. 1—T.S. pharynx. Fig. 2—T.S. oesophagus. Fig. 3—Portion of wall of oesophagus enlarged. Fig. 4—T.S. stomach. wall. Fig. 5—T.S. siphon. (All measurements expressed in millimetres. Figs. 1–2 drawn to the same scale.) Abbreviations: CEP, coclomic epithelium; CI, connective tissue: CM, circular muscle fibres; CU, cuticle; EMC, external marginal canal; ICT, interradial connective tissue; IEP, internal epithelium; IMC, internal marginal canal; LA, lacuna; LEP, epithelium of lantern coelom; LM, longitudinal muscle fibres; ME, mesentery; MM, muscle layer; MU, mucin; RHV, radial haemal canal; RR, radial ridge of connective tissue; SI, siphon; V, vacuole.
to those constituting the external epithelium of the pharynx. The muscle layer (MM) of the oesophagus is also relatively narrow but rather better developed than in the pharynx. There is an outer layer of circular fibres (CM), with longitudinal fibres (LM) also present, between the circular muscle and the connective tissue. In Echinus an opposite arrangement of the muscle layers of the oesophagus is described by Delage and Hérouard (1903). The connective tissue (CT) is not as thick in the oesophagus as it is in the pharynx and varies in width around the diameter of the oesophagus. It has an open mesh-like structure, forming lacunae (LA), in which the liquids of the haemal system circulate. The folded internal epithelium (IEP) is also of the pseudo-stratified type, as is the whole internal surface of the gut. It also contains numerous mucin-secreting (MU) cells, but these are not localized in any way like those of the pharynx. A strong cuticle (CU) is present on its inner border. The lacunal vessels accompanying the oesophagus (IMC, EMC) and the mesentery (ME) uniting it to the diverticulum and the apical pole are also revealed in cross section.
The muscle layer of the stomach (Text-fig. 10, Fig. 4) is chiefly composed of longitudinal fibres (LM) although a few circular fibres are present. The connective tissue layer is of fairly uniform width with many large lacunal spaces (LA). The internal epithelium is high and extensively folded, with very short cilia present on its inner border. It is extremely vacuolated (V), but no stainable material could be detected in the vacuoles. This vacuolation, and the great development of the lacunae, are in accord with the function of the stomach, which is the main digesting and absorbing region of the alimentary canal.
The histology of the diverticulum is very similar to that of the stomach, the main difference being in the cells of the internal epithelium, which in the diverticulum are crammed with a pink-staining granular material. There is no sign of any special glandular formation in the diverticulum, which, as Bannet points out, is a special glandular formation in the diverticulum, which, as Bonnet points out, is a junction of the oesophagus with the diverticulum a sharp transition could be seen from the dark-stained mucous-containing cells of the oesophagus to those of the diverticulum where practically no mucous is secreted.
The muscle fibres surrounding the siphon (Text-fig. 10, Fig. 5) are mainly circular (CM), and some of them are continued up into the internal mesentery The connective tissue (CT) encloses large lacunae, and varies in width following the folds of the internal epithelium (IEP). This is also of the pseudo-stratified type but is not so vacuolated as that of the stomach, and has a conspicuous granular border. Very short cilia are present on the cells bounding the lumen.
Cross sections of the stomach show the internal and external marginal canals excavated in connective tissue. The internal marginal canal (Text-fig. 10, Fig. 5, IMC) is also surrounded by circular muscle fibres and so is evidently contractile like the internal marginal canal of spatangids.
The wall of the intestine is of much the same structure as the stomach, except that the connective tissue layer is thinner and contains fewer lacunae, while the internal epithelium is lower, less folded, and does not contain so many vacuoles.
The rectum is rather more muscular than the intestine, with circular fibres quite well developed. Longitudinal muscle fibres are also present within the connective tissue of the internal mesentery. The connective tissue layer is thin, containing a few lacunae, while the internal epithelium is higher than in the intestine and quite extensively folded .The cells are rather more vacuolated than one would expect to find in a presumably inactive organ such as the rectum.
Examination of the internal epithelium of the stomach and intestine is made especially difficult because of the great delicacy of this layer and the readiness with which it comes away from the underlying connective tissue. In collections of gut
contents much of the internal epithelium of the gut wall is found mixed with the food materials.
In all references which I have consulted the internal epithelium of the entire alimentary canal of echinoids is described as being ciliated. I have experienced great difficulty in locating any cilia, except on the internal epithelium of the siphon and the stomach. Elsewhere they could not be identified with certainty, even when using an oil immersion objective. I would hesitate to say, therefore, that the entire interior surface of the alimentary canal is ciliated in Evechinus.
(Text-fig. 11; 12; 13; Fig. 5.)
Dissection. The tube-feet lying in two broad zones on either side of each radius are the external indication of the ambulacral canals and ampullae passing up the internal surface of the test. In the central axis of the animal the water, or stone, canal can be seen passing from the madreporite to the top of the lantern, closely associated with the axial organ. The ambulacral ring and its appendages may be observed by the use of a hand lens.
The water vascular, or ambulacral, system, corresponds to a ramifying coelomic cavity called the hydrocoel which is developed from the left anterior enterocoel of the larva. It serves the dual function of respiration and locomotion and is peculiar to the Echinodermata.
The ambulacral system communicates with the exterior through the pores of the sieve-like madreporite (Text-fig. 12, Fig. 1). The minute canals (MC) leading from the pores are lined for the upper third of their length by a high epithelium possessing numerous long cilia, which gradually merges into a flat epithelium, also ciliated, though not so conspicuously. Occasionally the canals may be seen to branch but most lead straight down to the thin-walled collecting chamber, or madreporic ampulla (MAP) lying immediately beneath the madreporite.
From the ampulla, the stone canal (Text-fig. 12, Fig. 2), closely adhering to the axial organ, leads down in the central axis of the animal to join the ambulacral ring, in interradius 2, at the top of the lantern (Text-fig. 12, Fig. 3, SC). It may be seen as a thin white strand on the wall of the axial organ to which it is joined by a sheet of connective tissue.
The ambulacral ring (AR), as in all echinoids where a lantern is present, has been pushed up to lie at the top of the lantern, thus coming to encircle the oesophagus instead of the mouth. It is pentagonal in shape, with transparent walls, and lies close against the axial ends of the lantern ossicles (Text-fig. 12, figs. 3–5).
In the five interradii short branches pass from the ring to the Polian vesicles (PV). These are small, slightly bilobed bodies, usuallv brown in colour, and often partially obscured by the compass elevator muscles (Text-fig. 12, figs. 3–4). They are lymphoid in nature. Their exact function is rather obscure but is probably the same as that of the brown gland—i.e., the elaboration of amoebocytes. Branches from the haemal ring also pass to them so that they form a link between the ambulacral and haemal systems. Most authors refer to them as “Polian vesicles”, apparently homologous with the paired structures of that name present in the Asteroidea. (Lang, 1896; Chadwick, 1900.) MacBride (1906), however, considers them to correspond instead to Tiedmann's bodies, as he regards the asteroid Polian vesicles chiefly as storehouses of fluid for the ambulacral system, while it is Tiedmann's bodies which are concerned solely with the production of amoebocytes. Cuénot (1948), on the other hand, does not commit himself to any homology but refers to them simply as “amas spongieux”.
In the five radii, the radial ambulacral canals (RAC) are given off, which pass out horizontally beneath the rotulae of the lantern (Text-fig. 12, Fig. 4), make an angle of 90° at the edge of the lantern, and can be seen running down its outer
Text-fig. 11.—Ambulacral System. Fig. 1—Tube-foot from adoral surface. Fig. 2—L.S. tube-foot and ampulla. Fig. 3—T.S. tube-fot. Fig. 4—Adoral ampulla. Fig. 5—L.S. wall of ampulla enlarged. Fig. 6—Interior view of apical ambulacrum of a specimen 39 mm diameter. (All measurements expressed in millimetres.) Abbreviations: AP, ampulla; CEP, coelomic epithelium; CT, connective tissue; DP, pore-pairs; ECT, elastic connective tissue; EP, external epithelium; EXC, excurrent canal; ICF, internal cavity of tube-foot; IEP, internal epithelium; INC, incurrent canal; LT, lateral canal; LM, longitudinal muscle; LV, valve of lateral canal; M, madreporite; NP, podial nerve; NX, nerve plexus; OC, ocular plate; OCP, ocular pore; OP, single pore; RAC, radial ambulacral canal; SK, sucker; SP, spicules; T, test; TB, trabecula; WC, crystalline pigment; XL, xtalline plate.
surface, lying against the intermediate muscles between the jaws (Text-fig. 7, Fig. 7). After giving off branches to the buccal tube-feet belonging to that radius, each canal then passes under the archway formed by the fusion of the apophyses, and continues up the interior wall of the test (Text-fig. 13, Fig. 5), giving off numerous branches on either side of the ampullae of the tube-feet. It finally ends blindly by perforating the ocular plate in each radius in the form of a small sensory terminal tentacle.
The ampullae (Text-fig. 11, Figs. 4–5) are the most obvious internal structures belonging to the ambulacral system. Because the tube-feet are numerous and crowded together, the ampullae are correspondingly numerous and flattened together, projecting like the leaves of a book into the cavity of the test. They are roughly mitre-shaped vesicles, 4 mm to 5 mm wide, and standing about 6 mm from the inner wall of the test, when the tube-feet are contracted as in preserved specimens. Their semi-transparent walls, on microscopic examination, are seen to have thin bands of muscle, or trabeculae (TB) passing across them, converging towards the base of each ampulla, where two openings lead to the lumen of the tube-foot. On the median side, near the base, the lateral canal (LT) from the radial vessel may be seen entering the ampulla. It is provided with a muscular valve (LV) which prevents any return of the ambulacral fluid back into the radial canal (Lang, 1896). In Echinus, as figured by both Chadwick (1900) and MacBride (1906), the pores leading to the tube-feet and the entrance of the lateral canal appear to be much closer together than in Evechinus, the median pore being practically continuous with that of the lateral canal Heliocidaris erythrogramma is similar to Evechinus in this respect.
Although the ampullae of the aboral surface are principally respiratory structures and might be expected to be larger and more conspicuously thin-walled than those of the aboral region, they show no such differentiation. There is instead a gradation in size, the ampullae of the adoral surface becoming slightly larger as they approach the ambitus and then smaller again as the ambulacra ascend to the apex.
Lang (1896) states that in young echinoids the tube-feet are connected with their ampullae by a single pore only. This may be so immediately after metamorphosis but in young specimens which I examined the only single pores present were those in the two rows of ambulacral plates immediately behind the ocular plates (Text-fig. 11, Fig. 6, OP).
The tube-feet, or podia (Text-fig. 11, Figs. 1–3), lying in a double row in the five radii of the animal, are the only external structures associated with the ambulacral system. They are highly contractile organs, which may be extended twice as far as the length of the spines or contracted down to only a few millimetres in length. In this contracted condition they have an annulated appearance. They have no conspicuous coloration in preserved specimens, but in the living animal they are dark red, merging near the test to a pearly grey. When extended they look very attractive waving about in the water beyond the outer limit of the spines. The internal cavity (ICF) may be seen in whole mounts (Text-fig. 11, Fig. 1) as a less dense central area. A round sucker (SK) is present at the distal end, which is supported by a delicate calcareous plate, the xtalline plate (XL), sometimes called the “rosette” or “pellion” (Bather, 1900.) This is composed of 6 or 7 segments held together by a central calcareous ring, extending a little below the level of the rest of the plate. The outer edge of each segment is spiked with finger-like projections which are continued in about half way to the centre of the plate like supporting ribs. Other isolated spicules basically of the bihamate type (SP) may be seen scattered along the tube-foot, especially at its distal end Mortensen (1943) describes them as being rather scarce, but all tube-feet which I have examined have contained quite large numbers of them. He figures them as completely smooth C-shapes, but one to four small conical projections can be seen, usually at one or both ends and sometimes at the centre of the spicule (Text-fig. 3, Fig. 8).
In Evechinus chloroticus, as in most regular echinoids (Lang, 1896) there is very little evidence of polymorphism in the tube-feet. They are all of the simple “homiopod” type of Cuénot (1948). However, slight differences, quantitative rather than qualitative, may be seen between those on the adoral and aboral surfaces of the animal.
Most conspicuously differentiated are the five pairs of buccal tube-feet which arise from small plates imbedded in the peristome. They are highly contractile structures which makes it difficult to obtain them as good mounts. The shape of the sucker with its supporting xtalline plate is oval instead of round. The plate has only four or five component segments but otherwise presents the same structure as that in the other tube-feet. Spicules are abundant and also a few large ones of irregular shapes (Text-fig. 3, Fig. 9). Internally it may be seen that these organs do not possess ampullae. This is probably because they function as gustatory organs (Lang, 1896, et al.) and so do not require the constant stream of water passing through them necessary for locomotion and respiration. The xtalline plate would thus appear to have no function, but remains as a merely vestigial structure.
The remainder of the tube-feet on the oral surface are of the typical homiopod structure and function primarily as locomotory structures, although some respiratory exchange must take place. In the usual contracted condition seen in the laboratory they are about 7 mm long, but in the living animal they may be greatly extended, sometimes twice the length of the spines. The diameter of the disc is of the order of 1.5 mm. Locomotion is effected by contraction of the ampullae, which forces the liquid within them into the tube-feet, causing them to extend. The suckers are then able to take grip on fresh ground and haul along the rest of the body (MacBride, 1906). This type of locomotion, however, is only possible over hard surfaces such as the rocky bottoms on which Evechinus is most frequently found. On loose surfaces such as sand the spines take over the function of locomotion.
On the aboral surface the tube-feet gradually become smaller and less muscular, finally ending in the small terminal tentacles at the top of each ambulacrum. Many are of the order of 3 mm in length, decreasing to about 1 mm at the apex, but these again may be extended far beyond the tips of the spines. The xtalline plate is present, but is less robust, with bigger spaces between its constituent spicules.
The suckers of these tube-feet can seldom, if ever, be used for locomotion, but have instead a protective function, either against light or predators. (See section on Ecology and Behaviour.) Mortensen (1943) records Evechinus, like so many other littoral echinoids—e.g., Echinus miliaris (MacBride, 1906), covering itself with shells, stones, algae, etc, and I have often seen animals using their aboral tube-feet for this purpose. The force required to remove these protective coverings indicates that the suckers, though reduced in size, are still quite powerful.
The principal function of the aboral tube-feet, however, is respiration, which is made easier by the comparative thinness of their walls. The ambulacral fluid flows through the lateral canals from the radial canal to the ampullae. The cilia lining each ampulla direct the fluid into the incurrent canal (Text-fig. 11, Figs. 2, 4, INC), that nearest to the radius, leading into the lumen of the tube-foot. Here a gaseous exchange is able to take place through the thin walls of the tube-foot. The oxygen-containing fluid is then transported back through the adradial excurrent canal (EXC) into the ampulla, where the oxygen is able to diffuse through its wall into the general body cavity. The fluid is said (Cuénot, 1948) to contain the same type of cells as are present in the coelomic fluid. Neither colourless amocbocytes, nor flagellates have been observed in Evechinus, but the radial canals and particularly the tips of the ampullae (Text-fig. 11, Fig. 4, WC), become pigmented by the deposition of echinochrome and yellow crystals of waste materials, indicating the presence of enhinochrome amoebocytes and munform cells.
The direction of flow through the madreporite was for some time problematical. It has, however, now been established by Cuénot (1948) that the current flows from the madreporite to the oral ring, thus maintaining the system in the state of turgidity necessary for its proper functioning.
Histology of the ambulacral system
The cells composing the walls of the organs and vessels of the ambulacral system are found in the four main layers typical of echinoids (Lang, 1896):
(1) Outer epithelium. In the case of the tube-feet (Text-fig. 11, Fig. 3) this is part of the external, pseudo-stratified epithelium (EP) covering the whole external surface of the body. All the remaining organs and vessels are covered by the ciliated peritoneum of the body cavity (CEP). Only those parts which are actually within the body wall—i.e., the canals connecting the tube-feet to the ampullae—are devoid of this outer epithelium.
(2) The connective tissue layer (CT) is very thin in most parts of the ambulacral system except in the tube-feet where it is well developed. Here there are no circular muscle fibres, their place being taken instead by strong elastic fibres (ECT) developed in the connective tissue. Spicules are often present within its meshes, notably in the tube-feet where they are very numerous, but a few may also be found in the ampullae. The xtalline plates of the tube-feet also lie within this connective tissue layer.
(3) Muscle layer. This is lacking in all parts of the ambulacral system except the ampullae and the tube-feet. In the ampullae (Text-fig. 11, Figs. 4–5) it is a discontinuous layer in the form of parallel bands of muscle, or trabeculae (TB), passing through the lumen of the ampulla and converging towards the openings to the tube-feet. In this way the ampulla is enabled to have sufficient contractility to extend the tube-feet in locomotion and yet remain sufficiently thin-walled to play the major part in the animal's respiration. The tube-feet owe their contractility to a thick band of longitudinal muscle (Text-fig. 11, figs. 2–3, LM) which is continuous with that lining the canals through the test wall to the ampullae (Text-fig. 11, Fig. 2).
(4) Internal epithelium. This is a low ciliated epithelium continuous throughout the whole system. In the stone canal (Text-fig. 12, Fig. 2), however, it is represented by a higher, pseudo-stratified epithelium (IEP), thrown into folds. It has numerous, long cilia (CIL). Chadwick (1900) describes the corresponding epithelium in Echinus as columnar.
Mention must be made here of the nervous tissue connected with the ambulacral system. In transverse sections of the ambulacra (Text-Fig. 13, Fig. 5) the large radial nerve is very conspicuous lying below the radial ambulacral canal and separated from it by the pseudohaemal canal, but this will be described later in the section dealing with the nervous system. The large nerve supplying the tube-foot is also quite conspicuous in transverse sections of that organ, lying between the connective tissue layer and the external epithelium.
The Axial Organ
(Text-fig. 12, Figs. 1, 3; Text-fig. 13, Figs. 1–2.)
Dissection. The axial organ may be seen, on opening the body cavity (Text-fig. 6), as a brown fusiform body suspended by mesentery in the central axis of the body. Its intimate relationships may only be determined by sectioning.
The axial organ lies in the central axis of the body suspended by a mesentery from the apical pole and also having a close mesenteric attachment (Text-fig. 13, Fig. 1, ME) to the oesophagus. It is fusiform in shape, tapering at both ends to a thin strand. In mature specimens it is a brown colour, probably due to ramifications of the lacunal system over its periphery, and also to the deposition of pigment
Text-fig. 12.—Ambulacral and Lacunal Systems. Fig. 1—Decalcified madreporite. Fig. 2—T.S. stone canal. Fig. 3—Ambulacral ring and Polian vesicles. Fig. 4—L.S. upper portion of Aristotle's lantern. Fig. 5—T.S. ambulacral ring enlarged. (All measurements expressed in millimetres.) Abbreviations AB, amoebocvte; ABL, aboral lacunal ring; ABR, aboral ring sinus; AEP, internal epithelium of the axial sinus; AL, alveolus; AO, axial organ; AR, ambulacral ring; C, compass; CEM, compass elevator muscle; CEP, coelomic epithelium; CIL, cilia; CT, connective tissue; IEP, internal epithelium; IM, intermediate musle; LA, lacuna; LC, lantern coelom; LEP, epithelium lining lantern coelom; LL, long ligament of pharvnx; LT, lacunal ring; MAP, madieproic ampulla; MC, madrepoic canals, MM, muscle layer; OE, oesophagus; PG, pigment; PH pharvnx; PT, periproctal sinus; PV, Polian vesicle; R, rotula; RAC, radial ambulacral canal; RLC, roof of lantern coelom; SC, stone canal; TM, terminal sinus; TP, terminal process of axial organ; WC, crystals of waste.
within its tissues. In very young specimens, however, it is quite colourless. The stone canal (SC) may be seen as a narrow white strand passing up its side. Anatomically it is remarkably constant, and its structure in both Evechinus chloroticus and Heliocidaris erythrogramma is similar to that figured for Echinus esculentus (Chad-wick, 1900, et al.).
The structure of the organ can only be revealed by histological examination (Text-fig. 13, Fig. 1). It is then seen as as a mass of tissue, kidney-shaped in cross-section, lying between the peritoneum of the body cavity and the epithelium of the axial sinus. However, the organ has become so large, especially in its central region, as to encroach considerably on the cavity of the axial sinus (AX), which then appears as the lumen of the gland. In the embryo, according to Delage and Hérouard (1903), the axial sinus may be seen to be quite distinct, with the axial organ represented by an island of mesenchyme, lying between the sinus and the main coelom.
The organ has a typically lymphoid structure, consisting of numerous connective tissue fibres (FCT) stretched to form a fine mesh (CTM) on which the regularly shaped lymph cells are situated (Text-fig. 13, Fig. 2). This network is so dense as to form a solid mass in the peripheral region, or cortex (C), of the organ. Towards the centre, or medulla (MED), the network is much more open and small diverticula (DV) of the axial sinus may be seen projecting into it. The connective-tissue fibres in this central region are particularly well developed. Small branches from the main coelom also penetrate the organ in the peripheral region. They are given the name of canaliculae (CL) by Cuénot (1948). A layer of connective tissue (CT), continuous with the mesenteries supporting it, and also with that surrounding the stone canal, encloses the organ. In it may be seen numerous lacunae (LA), and here and there large masses of a yellow granular pigment (WC) which are thought to be deposited wastes. Masses of this pigment are also scattered throughout the gland, especially in the cortical region. Often it may be seen to have completely filled a lymph cell in the connective tissue network (Text-fig. 13, Fig. 2, WC). Amoebocytes formed by the lymph cells can also be seen scattered throughout the gland (Text-fig. 13, Fig. 2, AB).
In the oral region (Text-fig. 12, Fig. 3), the gland is continued as a thin strand on to the lacunal ring surrounding the oesophagus. It is indistinguishable from the stone canal to the naked eye, but under a low power microscope may be seen to be distinct. Aborally it is continued in the form of a small terminal process (TP) beyond the axial sinus into a small cavity, the terminal sinus (TM), lying next to the madreporic ampulla (Text-fig. 12, Fig. 1).
The function of the axial organ was for a long time obscure, to which the many names by which it has been known testifies. It has been variously described as the “heart”, “pseudo-heart”, “kidney”, “plastidogenic organ”, “lymph gland”, “dorsal organ”, “ovoid gland”, “brown gland” and “genital stolon” (Lang, 1896, et al).It may be seen from its typically lymphoid structure that its function is the elaboration of amoebocytes, and so the name of “lymph gland” would be quite appropriate. However, when Sarasins (1887), describing the organ in Asthenosoma, called it a nephridium, he was nearer the truth than at first sight appears, for the function of excretion in echinoids is performed by the phagocytic action of the amoebocytes produced by the axial organ. Also, wastes which are deposited in inactive crystalline form throughout the body are particularly abundant in the axial organ. The name “genital stolon” refers to the fact that the genital cells of the young echinoid arise in the axial organ and then migrate aborally to form a ring around the aboral sinus from which the gonads of the adult are derived. These relationships are discussed, however, in the section dealing with the reproductive system.
The axial organ thus appears to be almost identical histologically with the same organ in Echinus, although in cross-section it differs slightly, being kidney-shaped and rather diffuse, whereas it is rounded and more compact in Echinus. Chadwick (1900) describes the terminal process as perforating the madreporic ampulla in Echinus but this is not upheld by later workers (Cuénot, 1948). He also figures the axial sinus as extending down to lie next to the madreporic ampulla. In this I think he has mistaken the terminal sinus, as figured for the same animal by Cuénot, for the lower part of the axial sinus.
Cuénot (1948) describes a connection between the axial organ and the stone canal at their apical extremities. This was not seen in Evechinus although the terminal part of the axial organ does become closely associated with the corresponding part of the stone canal.
There seems to be some confusion as to whether the organ lies actually in or on the axial sinus. Lang (1896) and Chadwick (1900) both describe it as being surrounded by the sinus, but Cuénot (1948) describes the opposite condition—i.e., it surrounds the axial sinus. This certainly appears to be the condition in Evechinus.
(Text-figs. 6; 12, Fig. 1; Text-fig. 13, Figs. 1, 3, 5, 7.)
The coelom of Evechinus is spacious, and like that of all echinoderms, notable for its subdivision into several smaller parts (Lang, 1896). Some of these have already been referred to in describing the organs with which they are associated. However, for uniformity, they will be briefly mentioned again here. All those cavities which have arisen from any of the enterocoelic vessels of the larva are considered by Lang (1896) to be coelomic. They are lined throughout by a squamous or cuboidal endothelium, which is usually ciliated.
The most obvious division of the coelom is that constituting the general body cavity, which in Evechinus is almost filled by the large coils of the gut with its numerous folds, and by the massive gonads. About the central axis of the animal, however, there still remains quite a large amount of free space. The perforated mesenteries holding the gut and gonads in place incompletely partition the cavity.
The peripharyngeal, or lantern, coelom has already been described in connection with the alimentary system. It is completely separated from the main coelom, and as in all gnathostomous echinoids, is of large size, containing within it the ossicles and muscles of Aristotle's lantern. Attention is drawn to the fact that it also has subdivisions: (1) The five pairs of branchiae, or external gills, in each interradius. (2) The five large dental pockets surrounding the soft part of each tooth at the top of the lantern. As already mentioned, its function is respiratory.
The periproctal sinus (Text-fig. 12, Fig. 1, PT) surrounds the end of the rectum and at its lower edge is attached to the apical ossicles. A well defined ridge (Text-fig. 18, Fig. 7, PR) passes from ocular plates I and V on either side up to the madreporite, converging towards the genital pore in the shape of a V, and provides attachment for the limiting membrane of the sinus. A similar ridge is present on the apical plates of H. erythrogramma but is in the form of a discontinuous circle, being broken between plates. The wall of the sinus is formed from stout mesenteric sheets which have, however, a number of perforations communicating with the general body cavity.
Immediately above the periproctal sinus is a small completely closed space, the perianal sinus (Text-fig. 13, Fig. 7, PA). The wall of this sinus is attached to the edge of the periproct surrounding the anus. It does not appear to be muscular in Evechinus.
Also at the apical end of the animal is a sinus in the form of a ring (ABR) around the inner edge of the calyx. This is known as the aboral or ring sinus (Text-fig. 6, Fig. 1). The gonoducts pass through it without perforating its cavity and a haemal
strand (ABL) is to be found within its inner wall. An aboral nerve ring is also usually present in echinoids, but I was unable to demonstrate it in Evechinus chloroticus.
The axial or glandular sinus has already been described in the section describing the axial organ (Text-fig. 13, Fig. 1, AX). In very young echinoids it communicates with the aboral ring sinus, but this communication is lost in the adult. (Lang, 1896, et al).
The terminal sinus (TM), lying next to the madreporic ampulla and containing the terminal process of the axial organ, has also been previously described (Text-fig. 12, Fig. 1).
The madreporic ampulla (MAP) is described by Lang (1896) as also being of enterocoelic origin and so may be regarded as a small branch of the coelom. As he points out, this provides an open communication between a closed division of the coelom and the water vascular system or hydrocoel (Text-fig. 12, Fig. 1).
Two sets of radial divisions of the coelom also exist. They pass up the internal wall of the test in close connection with the radial nerves. The first of these are the epineural canals (Text-fig. 13, Figs. 3, 5, EC), which lie between the outer surface of the nerve and the test. Aborally they end blindly. In Echinus, they are said (Chad-wick, 1900) to thin out gradually as the mouth is approached, but in Evechinus there does not appear to be any decrease in diameter (Text-fig. 13, Fig. 3). A circular canal surrounds the mouth. The epineural vessels are considered homologous with the ambulacral grooves of asteroids, for in the Echinoidea as in the Holothuria and Ophiuroidea this groove has become roofed over to form a canal (Lang, 1896, et al.). The second set of radial canals are the pseudohaemal vessels (PC) sometimes known as perihaemal canals. They lie between the inner surface of the test and the radial ambulacral canal (Text-fig. 13, Figs. 3, 5), and have the same distribution as the epineural canals. They also possess an adoral, circular canal (PR). Their function is obscure.
The ambulacral system may also be considered as a much ramified coelomic cavity. It is sometimes known as the hydrocoel and is derived from the left anterior enterocoel of the larva (Lang, 1896, et al.).
It may be seen that the coelomic cavities of Evechinus conform to the typical echinoid pattern, and are almost identical with those of Echinus. The only differences are in small details—e.g., the well developed ridge on the apical plates providing attachment for the wall of the periproctal sinus is not described as being present in Echinus, while the muscles of the perianal sinus of Echinus could not be seen in Evechinus.
The coelomic fluid of echinoids has been analysed and is said by Cuénot (1948) to consist principally of sea water in which traces of nitrogen as protein and in the form of urea and ammoniates are present. There is also less chlorine than in sea water, but the two fluids remain isotonic because of the non-electrolytes present in the coelomic fluid.
Four types of cells are commonly present, and these have all been observed in Evechinus chloroticus and seem to correspond in nature and dimensions (Cuénot, 1948) to those found in Echinus esculentus.
(1) Phagocytic amoebocytes (Text-fig. 13, Fig. 10). These are small hyaline bodies, 10μ to 15μ in length, which usually have several long, slender, lobose pseudo-podia by which they engulf food and make slow progression through the fluid. They are frequently vacuolated and also have granular inclusions within their cytoplasm, which Cuénot (1948) says are “sans doute des produits de déchet solides fabriqués ou phagocytés par eux”. He says they are chiefly phagocytic although they also have
Text-fig. 13.—Axial Organ, Nervous System and Coelomic Cavities. Fig. 1—T.S. axial organ. Fig. 2—T.S. axial organ enlarged. Fig. 3—L.S. Aristotle's lantern near mouth. Fig. 4—Perrpharyngeal nerve ring enlarged. Fig. 5 T.S. ambulacium. Fig. 6—L.S. edga of an alveolus. Fig. 7—Interior view of apical ossicles. Fig. 8—Flagellate from coelomic fluid. Fig. 9—Muriform bodies. Fig. 10—Amoeboryte from coelomic fluid. Fig. 11—Echinochrome bodies. (All measurements expressed in millimetres. Figs. 8–11 all drawn to the same scale.) Abbreviations: A, anus; AB, amoebocyte; AL, alveolus; AX, cavity of axial sinus; C, cortex; CEP, coelomic epithelium; CL, canaliculae; CT, connective tissue; CTM, connective tissue mesh; DV, diverticulum; EC, epineural canal; EPH, internal epithclium of the pharynx; FCT, fibrous connective tissue; GC, ganglion cells; GF, superficial ganglion; IM, intermediate muscle; L, ligament; LA, lacuna; LC, lateral canal; LEP, epithilum of lantern codon; LO, lamella of deoper oral system; M, mouth; M, madreporite; ME, mesentery; MED, medulla; MM, musch; NA, nerve to alveolus; NE, nerve fibres; NPD, pharyngeal nerve of deeper oral system; NPF, pharyngeal nerve of superficial system; PHN, nerve to pharynx; PPN, pedal and peripheral nerves; NR, pen-pharygeal nerve ring; P, peristome; PA, perianal sinus; PC, perihaemal canal; PR, perihaemal ring; PW, pseudopod before being withdrawn; RAC, radial ambulacral canal; RHV, radial haemal vessel; RN, radial nerve; RP, periproctal ridge; RR, radial ridge of connective tissue; SC, stone canal; SH, short ligment of pharynx; WC, waste crystals.
athrocytic properties—i.e., they also have an affinity for injected dyes and other introduced colouring materials.
(2) Muriform cells (Text-fig. 13, Fig. 9). Amoebocytes, 10μ to 15μ in length, which move through the coelomic fluid by means of limax-type pseudopodia. There are numerous colourless granules included in their cytoplasm. They are neither phagocytic nor athrocytic but are thought by Cuénot (1948) to be protein reserves.
(3) Echinochrome amoebocytes (Text-fig. 13, Fig. 11). These cells are very similar to the muriform bodies but are usually slightly larger (20μ) and contain the pigment echinochrome which gives them a deep brownish-red colour. This is apparently only present in the endoplasm, for when their pseudopodia are being withdrawn the colourless ectoplasm may be seen as a clear outer shell left behind when the dark red endoplasm has been withdrawn (PW). They also are neither phagocytic nor athrocytic. Cuénot (1948) notes that together with the muriform cells they are always abundant in parts of the animal which are in the process of formation or regeneration.
(4) Flagellates (Text-fig. 13, Fig. 8). These are very numerous and may be seen swimming actively through the fluid by means of their very long single flagellum (35μ in length). The body is small and globular, approximately 5μ in diameter. Vacuoles and granular inclusions are occasionally seen in the usually hyaline protoplasm. It is not known whether they are parasitic Protozoa or cells elaborated by the animal itself. Cuénot (1948) says “on ne sait trop si ce sont des éléments normaux du liquide coelomique ou bien des Flagellés parasites du genre Oikomonas; le fait qu'on les trouve d'une façon constante chez les Cidaridés, les Réguliers et les Clypéastroides, en nombre toujours considérable, n'est pas favorable à l'hypothèse parasitaire”.
The liquid fresh from the animal is a pale rose colour due to the dispersed echinochrome bodies it contains, but after standing for a short while a reddish coloured clot is formed floating on the surface. This is caused by the colourless amoebocytes uniting to form a network within the meshes of which the echino-chrome and muriform cells become entrapped. Cuénot (1948) points out that this pseudo-clot plays an important role in the healing of wounds. Some such mechanism is probably effective in other classes of Echinodermata for the group in general is described as having extensive powers of regeneration.
(Text-fig. 6; 10, Figs. 2,4,5; Text-fig. 12, Figs. 1, 3–5; Text-fig. 13, Figs. 1, 3.)
Dissection. The two marginal canals on the gut can be readily observed during the course of dissection as two thin white strands on either side of the oesophagus and stomach. Sometimes they may be quite red in colour, probably due to the presence of numerous echinochrome bodies within them. The collateral canal is quite transparent and readily seen floating above the lantern in the general body cavity. Sectioning is necessary to observe all other parts of the system.
In the Echinodermata, particularly the Echinoidea and Holothuria, food materials are absorbed and transported from the gut to other parts of the body by a number of lacunae of varying size which collectively are known as the lacunal or haemal, system (Lang, 1896, et al.). The lacunae (LA) are merely spaces excavated within the connective tissues of the various organs and do not possess any true endothelial lining. Some are very small spaces, such as those developed within the wall of the intestine, while others again coalesce to form bundles of canals running together in definite directions, and may attain quite large size. Some may even have muscular walls.
I have followed Bonnet's (1925) terminology in describing this system. He prefers to use the term canal rather than vessel for the larger aggregations of lacunae because it can be equally well applied to a single, microscopic lacuna. “Nous em-
ploierons, pour désigner les différentes portions de l'appareil absorbant, le terme de canal qui peut s'appliquer aussi bien aux conduits d'aspect vasculaire libre dans la cavité générale, qu'aux réseaux lacunaire de l'intestine.”
The two main haemal canals lie on either side of the gut, the internal marginal canal (IMC) on the inner or axial border of the stomach and the external marginal canal (EMC) developed on its outer surface. They are also sometimes known as “ventral” and “dorsal” canals respectively, but these are not good terms when applied to the adults of the Eleutherozoa. It is best to reserve them for description of the larvae, as these alone possess a primary bilateral symmetry (Lang, 1896, et al.). Each canal arises at the top of the lantein, and passes down either side of the oesophagus, the external canal lying at the root of the mesentery uniting the oesophagus and the axial organ (Text-Fig. 6, EMC), while the internal canal lies on the opposite or free surface (Text-Fig. 6, IMC) Cuénot (1948), and Delage and Hérouard (1903) describe the internal canal alone as being present on the oesophagus Chadwick (1900), Lang (1896), and MacBride (1906), however, describe both canals as being present, which is the condition in Evechinus. In section, however (Text-Fig. 10, Fig. 2), the external marginal canal is seen to be little more than a strand of connective tissue, while the internal marginal canal is excavated as a true canal.
At the junction between the oesophagus and stomach the internal canal passes on to the top of the siphon (Text-fig. 9; Text-fig. 10, Fig. 5), which it accompanies throughout its whole course, round the body and back to radius II. Here it passes on to the mesentery uniting the upward coil of the gut in that radius (Text-fig. 9), and finally loses its identity by breaking up into small lacunae on the internal mesentery of the intestine Similarly, the external canal passes from the oesophagus on to the diverticulum (Text-fig. 6), and thence to the external border of the stomach It is in general finer than the internal canal, and like it becomes lost on the surface of the intestine A network of small branching lacunae, excavated in the connective tissue of the stomach wall, pass between the two main canals They may be seen in transverse sections of the stomach (Text-fig. 10, Fig. 4), and to a lesser extent in the wall of the intestine. In radius II, the external marginal canal suddenly increases in diameter due to its junction with a large subsidiary vessel which runs parallel with it. This is the collateral canal (Text-Fig. 6, CL). It is independent of the gut and floats freely above the lantern in the general body cavity. At its two extremities—i.e., in interradu 3 and 1—it is continuous with the external canal, while in the interradu 4, 5 and 3 anastamoses connect the two canals It apparently functions as a reservoir for surplus liquid absorbed by the lacunae of the stomach wall. This canal is not present in all echinoids. Chadwick (1900) does not describe it in Echinus, but Bonnet (1925) says it does exist in that genus, and also in Psammechinus and Sphaerechinus, in all of which it follows an identical course with that of Evechinus. He did not find it present in Cidaris, Arbacia or Paracentrotus. I have found it present in Heliocidaris erythrogramma.
The presence of a lacunal ring about the oesophagus at the top of the lantern is problematical in echinoids Cuénot (1948), Delage and Hérouard (1903) and MacBride (1906) all describe it as being present. “Elle entoure la base de l'oesophage, à coté du canal oral qu'elle suit exactement, placée un peu au-dessous et en dehors de lui” Chadwick (1900) says, “the existence of such a separate circular vessel is, however, open to doubt and this remark applies with greater force to the blood vessels which have been described as radiating from it, and traversing the ambulacra between the water-vascular and pseudohaemal canals. Such vessels are not evident in carefully prepared serial sections of the ambulacra”. I was not able to observe this circumoesophageal ring, nor its supposed branches to the Polian vesicles, even when examined under a binocular microscope. I had hoped to demonstrate it by injection of the lacunal system, but the attempts were unsuccessful. A lantern was then decalcified and sectioned to reveal the true nature of the haemal
ring (Text-fig. 12, Fig. 4). It was found that part of the wall of the wall of the ambulacral ring (AR) had a large mass of connective tissue (LT) adhering to it, in which numerous lacunae of varying sizes were developed. This, then, must correspond to the haemal ring described by Cuénot (1948) and others. In the interradii the lumen of the ambulacral ring becomes continuous with that of the Polian vesicles so that the strip of lacunal tissue is continuous with their wall, thus forming interradial branches from the haemal ring.
From the lacunal ring five radial vessels descend the pharynx, lying outside the radial ridges of connective tissue. They may be seen in cross sections of that organ (Text-fig. 10, Fig. 1, RHV). Each is then said to cross the peristome and accompany the radial nerve and three radial canals up the five ambulacra, giving off lateral branches to the tube-feet, and finally ending in the terminal tentacle of the ocular plate. They are described as inserted between the water-vascular canal and perihaemal vessel. I have not been able to observe them in any sections which I have cut of the ambulacra, but in sections of the lantern at the level of the mouth (Text-fig. 13, Fig. 3) they could be seen passing from the side of the pharynx to join the radial vessels. Thus, though they are well developed near the mouth, they must gradually thin out to disappear completely by the time the ambital region is reached.
The connective tissue surrounding the periphery of the axial organ has already been described as containing numerous lacunae, (Text-fig. 13, Fig. 1). From the adoral end of the gland a strand of connective tissue accompanies the stone canal and passes on to the lacunal tissue associated with the ambulacral ring (Text-fig. 12, Fig. 3). Aborally, a thin haemal strand is developed in the wall of the aboral ring sinus (Text-fig. 12, Fig. 1). The wall of the gonad also contains a lacunal plexus in most echinoids, but this is not well developed in Evechinus. The wall is very thin and the connective tissue little developed in all sections which I examined.
The fluid circulating through the lacunae is similar to the coelomic fluid, but according to Lang (1896) contains much more albumen in solution. It contains the same kinds of cells floating within it. In most echinoids there is no muscle developed in the walls of the lacunae, so that there is only a slow displacement of the fluid, with no active circulation caused by contracting vessels. The axial organ was once thought to have such contractility and so was given its inappropriate names of “heart” and “pseudoheart”. The internal marginal canal of spatangids, however, has been seen (Cuénot, 1948) to exhibit irregular contractions, and this may also be the case in Evechinus. for in cross section the wall of the internal marginal canal is seen to be quite muscular. (Text-fig. 10, Fig. 5, CM).
(Text-fig. 13, figs. 3–6.)
Dissection. The radial nerves are easily observed lying under the ambulacral canals passing up the test in each radius. The remainder of the nervous system, however, may only be observed by sectioning.
The nervous system of echinoderms is now considered to consist of three independent systems: (1) the superficial oral system; (2) the deeper oral system; (3) the apical nervous system. In accord with the marked radial symmetry of the animal there is no central ganglionic mass or “brain” to co-ordinate movements. It might be expected that such a structure would develop in forms such as the irregular echinoids which have reverted to a tertiary bilateral symmetry, but evidently this is not so. MacBride (1906) has very neatly described the condition in echinoids: “In a dog the animal moves its legs, in a sea-urchin the legs move the animal”.
Originally the superficial oral system, or ectoneural system, was the only one known (Lang, 1896), and in the Echinoidea it is certainly the most obvious system. The term “superficial” is used to describe it because in the Crinoidea and Astero-
idea it occupies an epithelial position throughout life. In all other echinoderms, however, it has sunk to a position below the body epithelium, and in echinoids it is to be found actually within the test wall, inside the body cavity (Lang, 1896, et al.).
A central ring of nerve cells and fibres (NR) surrounds the mouth at the base of the lantern (Text-fig. 13, Figs. 3 and 4). Unlike the ambulacral ring, it has not become lifted up by the lantern and so occupies the same position in Evechinus as it does in agnathostomous sea-urchins. Ganglion cells (GC) form a dense, deeply-staining mass on its most adoral surface, while the remainder of the ring consists of nerve fibres (NF) among which a few scattered nerve cells may be seen. From the nerve ring in each radius nerves pass on to the pharynx (NPF) and gradually break up into a plexus, said to be still traceable on the wall of the stomach (Lang, 1896). A radial nerve trunk (RN) is also given off in each radius. It passes across the peristome, inserted between the perihaemal (aboral) and epineural (adoral) canals, to meet the radial ambulacral canals descending from the top of the lantern, so that all radial structures pass up the centre of each ambulacrum together (Text-fig. 13, Fig. 5, RN). It has the same histological structure as the nerve ring except that here the nerve fibres run longitudinally instead of being circular. Alternate branches (NPP) are given off to accompany the lateral canals of the ambulacral system to the tube-feet. These branches really consist of two nerves. One of them passes up the side of the tube-foot as the pedal nerve (Text-fig. 11, Fig. 3, NP), which is said to expand under the disc of each tube-foot as an intraepithelial ring (Lang, 1896). In this way the tube-feet must be able to function to some extent as tactile organs The other nerve is a peripheral nerve, and unites with the many other similar nerves to form a nerve plexus deep in the epithelium covering the exterior of the body. It is this nerve plexus which effects the movements of the sphaeridia, pedicellariae and spines. In sections of sphaeridia and spines a nerve ring may be seen passing around the base of each (Text-fig. 4, Figs. 7 and 8), while the sensory cushion of the gemmiform pedicellariae can be observed in sections of that organ (Text-fig. 4, Fig. 3). Cuénot (1948) describes the peripheral nerves of echinoids as often leaving a visible trace or groove on the test, which is particularly evident in species of Cidaris. No such grooves can be seen in Evechinus, but the wall of the most radial pore of each pore-pair is broken down at the point of emergence of each peripheral nerve (Text-fig. 1, Figs. 2 and 3).
The deeper oral nervous system is only present in those echinoids which possess a lantern (Lang, 1896). It is usually in close association with the superficial system, so that macroscopically it is impossible to distinguish the two. However, high magnification reveals the nerves of the deeper system lying on the inner or axial border of superficial nerves (Text-fig. 13, Fig. 4). In the Ophiuroidea and Asteroidea there is a complete ring surrounding the oesophagus, but this is wanting in the Echinoidea and Holothuroidea (Lang, 1896). Instead, there are five lamellae (LO) consisting of both nerve cells and fibres which may be seen in Evechinus lying in close contact with the pharyngeal ring of the superficial system. From these lamellae nerves pass on to the pharynx in close association with the superficial nerves (NPD), and also on to the edges of the alveoli, up which they ascend (Text-fig. 13, Fig. 6, NA), and probably ramify to supply the jaw muscles. Delage and Hérouard (1903) claim that a short nerve typically passes back for a short distance lying on top of the radial trunks. However, this was not seen in Evechinus.
An apical, or aboral, ring is described by most authors (Lang, 1896, et al.) as a delicate nerve trunk running within the wall of the aboral sinus Sectioning of the sinus, however, did not reveal it in Evechinus, although the use of specific nerve stains might possibly reveal it.
There appears to be little deviation among echinoids from this basic pattern of nervous system. Even the irregular urchins, in which one might expect to find
Text-fig.. 14.—Reproductive System. Adoral View with Cut Removed. Abbreviations: ADC, adoral gonad; AO, axial organ; AP, ampulla; APG, coalesced apical mass of gonad; BG, minor branches of gonad; MES, mesentery; R, rectum; RAC, radial ambulacral canal.
some central co-ordinating area developed, conform to it. Thus as Evechinus and Echinus are both regular urchins one would expect their respective nervous systems to be almost identical, and this seems, indeed, to be the case. Histological study of Heliocidaris erythrogramma was outside this investigation, so that apart from the ladial nerve trunks the nervous system was not examined, but it would probably be very similar to that of Evechinus chloroticus.
(Text-fig. 6, 14, 15.)
Dissection. To observe the full extent of the reproductive system of Evechinus chloroticus it is necessary to open the animal from the adoral surface and completely remove the alimentary canal. In ordinary dissection this drastic treatment is best saved for the last stage of the dissection, after the alimentary canal has been studied sufficiently and is no longer required. To observe the gonoduct within the gonad, it is necessary to slit carefully, with a scalpel, up the midline of the gland from the axial side, washing away the contents of the cut follicles as they ooze out and obscure the dissection. It is most easily observed in those animals where the duct is filled with the genital products, as it is then opaque, with patches of pigment showing up clearly along it.
The reproductive organs (Text-fig. 15) are five large, arborescent glands lying in the interradii, extending from the apical pole down to the level of the lantern.
Text-fig. 15.—Reproductive System. Fig. 1—Genital plate No. 4 of a female. Fig. 2—Distal portion of the madreporite of a male. Fig. 3—Histology of mature female gonad. Fig. 4—Egg. Fig. 5—Ripe male follicle. Fig. 6—Histology of mature male gonad. Fig. 7—Developing gonad in a specimen of 19 mm d'imeter (All measurements expressed in millimetres. Figs. 1–2 drawn to the same scafe.) Abbreviations: FP, peritoneal epithelium; CT, connective tissue layer; F, follicle; FP, female papilla; FW, follicle wall; GD, gonoduct; GEP, germinal epithelium; GP, gonopore; IA, Interambulacral plate; M, madieporite; MM, muscle layer; MP, male papilla; MS, miliary spine; N, nucleus; NC, nutritive cell; NL. nucleolus; OG, Oogonium; OM, egg membrane; OP, ophicephalous pedicellaria; OY, oocyte; P, pigment; SS, secondary spine; ST, spermatids; SZ, spermatazoa; TF, trifoliate pedicellaria; Y, yolk.
In mature forms the five glands coalesce at their apical extremities (APG), remaining unjoined, however, in radius III. From this coalesced apical mass several minor branches (BG) may also arise, apparently at random, with no relation to the general symmetry of the animal. The gonad in either interradius 2 or 3 may be rather smaller than those in the other interradii. Mortensen (1943), surprisingly, describes the gonad as uncoalesced, but I can only assume that he dissected young specimens in which the gonads were still separate, or else specimens which had previously been starved, possibly by being kept without food in an aquarium tank for a few weeks.
The great abundance of genital material is in contrast to the condition described for Echinus (Chadwick, 1900, et al.), where the gonads are restricted to the apical half of the body cavity, and where there is no coalescence between the neighbouring glands. The elongation of the glands in the interradii is similar to the condition in Sphaerechinus and Paracentrotus as described by Bonnet (1925). In Heliocidaris erythrogramma the gonads are also elongated dorso-ventrally. They are not, however, of such great volume and there is no apical coalescence. The gonoduct is quite conspicuous in this form and may be seen running down the length, of the gonad immediately below the inner or axial surface. In the matter of coalescence Evechinus more closely resembles Psammechinus, a genus closely allied to Echinus, in which the gonads are joined.
The walls of the gonad consist of numerous follicles (F) within which the sexual cells are formed. Running through the centre of each gland is a narrow, thin-walled gonoduct (GD) which receives branches from the follicles all along its length. Aborally (Text-fig. 6) it may be seen passing from the gonad to penetrate the test in a pore (GP) at the outer edge of each of the four genital plates or in interradius 2, the madreporite.
In a very young specimen of 19 mm diameter (Text-Fig. 15, Fig. 7), which I dissected, the gonads were just beginning to enlarge. All that could be seen of them at this stage was a central duct in each interradius along which small buds were just beginning to appear. This, together with the fact that the gonoduct has no specialized internal epithelium, suggests that the gonad has the structure of a large compound gland, with its follicles corresponding to numerous acini. The gonoduct is thus the first part of the gonad to make its appearance, and from it all other parts of the gland are derived.
The colour of the gonads examined varied from pale yellow to bright orange and orange-brown, depending on the degree of ripeness. Pale yellow in most cases signified that the gonad was full of genital products ready to be discharged. The colour did not appear to have any relation to sex, as it does in some echinoids, including Echinus (Chadwick, 1900). The only difference noted was in the colour of the exuded stream of sexual products. In males this was a viscous, milky-white fluid, while in females it was pale yellow and rather less viscous.
The genital cells of the Echinoidea, like those of the Asteroidea, Ophiuroidea and Crinoidea, are thought to arise in the axial organ and to migrate to form a ring, or genital strand, around the aboral sinus, from which the gonads of the adult are finally derived (Lang, 1896, et al.). This direct connection between the axial organ and the gonads apparently persists throughout life in the Asteroidea and Ophiuroidea, but in the Echinoidea it completely disappears in the adult. However, in a very small specimen of Evechinus chloroticus (diameter 19 mm) in which the gonads were just appearing as small buds from the central gonoduct in each interradius there was absolutely no sign of the genital strand. The genital strand must therefore, if present at all, atrophy at a very early stage in the development of the gonad.
A narrow strip of strictly interradial mesentery runs down the midline of each gonad securing it to the test Other mesenteries, in the form of fine strands, pass from the alimentary canal on to the gonads and have already been described in connection with the alimentary system.
It is difficult to distinguish between the sexes by external characters. A genital papilla is present in both sexes (Text-fig. 15, Figs. 1 and 2). The male papilla (MP) is rather more than 1 mm in length and is dark in colour with a white tip. There was no sign of glistening white edges at the base of the papilla as described by Swann (1953) for Sphaerechinus granularis, Echinus esculentus, Paracentrotus lividus, Psammechinus microtuberculatus and P. miliaris, the four latter species all belonging to the Family Echinidae. The male papilla of Heliocidaris erythrogramma is much the same shape and dimensions as that of E. chloroticus. The female papilla (Text-fig. 15, Fig. 1, FM) is short and conical (0.5 mm to 0.6 mm in height), terminating in a circular aperture ringed round by dark pigment. The same appeared to be true of H. erythrogramma although the material examined was not well preserved. In the species described by Swann the female genital apertures are not borne on papillae, but are slightly sunk below the level of the rest of the plate. They are of no use for field identification of the sexes, however, because they are small and difficult to detect in among the spines and pedicellariae, even when examining under a low power binocular microscope.
The genital pores are of about equal width (0.6 mm) in both males and females of Evechinus. This absence of any widening of the genital pores in the female is in agreement with the small egg size (0.1 mm). Also correlated with the small egg size, and consequent independence of the larvae, is the absence of any incubatory devices, such as are common in many Antarctic sea-urchins (Cuenot, 1948). It is surprising, however, that the genital pores of H. erythrogramma should also be like those of Evechinus, and show no widening in the female, as the eggs of that species are five times larger and undergo direct development (Mortensen, 1943).
It appears that animals in which the gonads are ripe may be obtained throughout most of the year, except during the middle of winter, for ripe specimens were obtained as late as the middle of June. Early in August artificial fertilization of three specimens by injection of potassium chloride was unsuccessful, although the animals were obviously strongly stimulated, and during September several specimens were collected from Island Bay none of which contained eggs or sperms. However, on the 1st October a large ripe female was obtained from Makara.
In July, 1953, two collecting trips were made to Oriental Bay, where specimens had been very abundant during the previous summer, but no Evechinus could be observed. This was also noted by B. E. Maxwell, who visited the area independently about the same time. It was thought, therefore, that the animals might only be present close inshore over the summer spawning period and might migrate out into deeper waters during the winter. However, over the same period in 1954, Evechinus was present in large numbers at Oriental Bay, while at Balena Bay throughout both 1953 and 1954 the number of animals present did not vary appreciably. There must, therefore, have been some other factor affecting the sea-urchins at Oriental Bay during the winter of 1953. The explanation mav even lie in a “kina” feast by some of the city's Maori population.
(Text-Fig. 15, figs. 3–6)
The wall (FW) surrounding each follicle of the gonad is very thin, but nevertheless three definite layers may be distinguished. (1) An outer layer of small cuboidal cells with conspicuous nucler. This is the peritoneal epithelium (EP) which covers all organs within the general body cavity. (2) A thin muscle layer (MM). (3) A narrow strand of connective tissue (CT). Between the peritoneum and the muscle layer is a space, described by Cuénot (1948) as “plus ou moins virtuel”, in which migratory cells may occasionally be seen.
The interior of each follicle is composed of a germinal epithelium (GEP). In animals where the gonad is not ripe the whole follicle is composed of the large
vesicular cells described by Cuénot (1948) which have a phagocytic action, engulfing those sperms and eggs left behind in the follicle after spawning. Globules of a yellow pigment (P) may be seen among them, and also new spermatagonia and oogonia beginning to develop.
In a ripe male the spermatazoa (SZ) are shed into the centre of each follicle (Text-fig. 15, Fig. 5) where they accumulate as a dense mass which is visible to the naked eye in stained sections. The sperms are narrow, tapering bodies, about 6μ in length, and are produced in numbers which must be astronomical. Surrounding this central mass are germinal cells still in the process of spermatogenesis (ST). In those sections which I was able to examine this process was fairly far advanced, most of the cells containing spermatids. A few large masses of pigment may be seen throughout the epithelium.
In the female (Text-Fig. 15, Fig. 3) the oogonia and oocytes are readily distinguished by virtue of their dark-staining yolk material. The oogonia (OG) are seen as small spherical cells in which the nucleus is still inconspicuous, lying among large, thin-walled nutritive cells (NC). The oocytes (OY) are much larger, with a conspicuous, vesicular nucleus (N) and large nucleolus (NL). The egg (Text-fig. 15, Fig. 4) is spherical, yellow brown in colour, and opaque with included yolk material. It has a diameter of 0.1 mm.
Moore (1934), working on the biology of Echinus esculentus, points out that the gonad is the one organ of the body in which the animal can store reserve food material, and this is probably true also for Evechinus chloroticus. Pigment is abundant and other cell inclusions may well be nutritive. This is borne out by the fact that in two sea-urchins which had been kept in an aquarium tank practically without food for two weeks the gonads were extremely reduced in volume, so that only a thin strand remained in each interradius. During that time the animals had been moving actively about, so that they were evidently maintaining themselves by drawing on the food reserves present in the gonads.
No parasites have previously been recorded from Evechinus chloroticus, but during the course of this study three animals have been discovered associated with the echinoid. None appears to be actually parasitic, if one defines that term as the condition where the parasite does actual bodily harm to the host. Two are endocommensal animals living in the gut—namely, a protozoan, the ciliate Anophrys elongata Biggar and Weinrich, and a rhabdocoel which appears to be a previously undescribed species of the genus Syndesmis, of which the species S. echinorum (Francois, 1886) is commonly found in the gut of European echinoids. The members of the Family Umagillidae, to which the genus belongs, are commonly commensal in the gut of echinoderms, although this appears to be the first record of the family from the Southern Hemisphere. The animal is bright red in colour, with a whitish streak, probably corresponding to the alimentary canal, in the dorsal mid-line. It is concave ventrally, and slightly convex dorsally, with the anterior end rounded and the posterior end sharply pointed. It is of the order of 2 mm-2.5 mm in length and 0.5 mm-1.0 mm in width. It is hoped to give a full description of the animal at a later date. Although infestation was fairly general, it was not on the whole heavy, two or three being the usual number found, although one specimen examined contained 18.
Another species of the same genus was also found in the gut of Heliocidaris erythrogramma and also appears to be previously undescribed. This rhabdocoel is 2 mm to 3 mm long and 1 mm to 1.5 mm wide, rather larger and more flattened than that found in the New Zealand echinoid. It was a whitish colour in preserved specimens, where, however, the natural coloration may have been lost. All the echinoids examined were heavily infested with this platyhelminth, one specimen
harbouring as many as 68, 20 of which were taken from the stomach. In Evechinus the intestine was the only part of the alimentary canal in which rhabdocoels were found.
Although only one species of ciliate was identified from the gut of Evechinus, it is probable that using techniques similar to those employed by Powers (1935), when he investigated the ciliates of Tortugas echinoids, many more could be discovered. Such a project was outside the scope of this investigation, however.
The ectocommensal animal living among the spines and pedicellariae of Evechinus is a small copepod which has yet to be positively identified. It may prove to be a common littoral copepod, such as Amphiascus littoralis (Stuckey, 1948), to which it appears superficially similar, which has extended its range to occupy an ecological niche similar to Echinocheres violaceus on Northern Hemisphere echinoids. That it is truly commensal is borne out by the fact that it is tolerated by the host and never grasped by its pedicellariae.
Ecology and Behaviour
As has already been mentioned, Evechinus chloroticus is to be found at Oriental and Balena Bays in large numbers, occurring in about knee-depth of water at low tide. Here the substratum is pebbly to stony, with the brown alga Carpophyllum maschalocarpum very abundant. This habitat is a little different from that described as typical for the species by Powell (1947), when he described the animal as being “found towards low tide in rock pools and crevices amongst seaweeds” Fell (1952) also describes it as being “especially a reef-dwelling, eulittoral form”, although he records it as tolerating a soft, muddy substrate, “the former Napier Inner Harbour before it was drained by the 1931 earthquake” However, at Island Bay, Wellington, which according to these authors would be an ideal habitat for the echinoid, Evechinus is quite scarce. Numerous trips to these collecting grounds have been made by members of the Zoology Department over the last two years, and at no time has Evechinus been found in large numbers, on several occasions not a single specimen having been seen. What has emerged from these observations, however, is the fact that Evechinus can apparently tolerate quite a wide range of littoral conditions. Most frequently the animals at Island Bay were found clinging to stones in positions where they were directly exposed to the ocean swell. Others again, however, were living in very different circumstances. Some were found in a high, shallow pool, which at low tide was completely isolated They were clinging to the sides, quite inconspicuous among the coralline seaweed. One was only about two inches below the water. Different conditions, again, are to be met with at Evans Bay, where the substratum is rather sandy but yet supports large numbers of Evechinus. It is therefore apparent that these animals are not limited to the rock pool environment, but are able to tolerate a wide range of littoral conditions. This tolerance is possibly one of the factors influencing the wide distribution of Evechinus chloroticus throughout the New Zealand region. Fell (1952) records fragments of a large individual taken by the “Alert” from Dusky Sound in 50 fathoms, but as he points out, this should not be treated as evidence that the species is able to live in such deep water.
The way in which many littoral echinoids hold pebbles, empty mollusc shells, seaweed, etc., on the aboral portion of the test has been observed by numerous authors. It has been suggested by Mortensen (1943) to be in response to the greatly increased light intensity of littoral conditions, rather than for protective purposes This may be true of Evechinus, for although the animal has no specific light-sensitive organs it does appear to be responsive to light in some degree. When placed under strong light for photography the tube-feet soon became contracted However, in any group of the animals living at approximately the same depth on the collecting grounds, and therefore under uniform conditions of illumination, some would be
covered with numerous such articles, while others were quite bare. It has also been noticed in the laboratory that animals which had been removed from the aquarium tank for any purpose, almost completely covered themselves with pebbles when replaced. Very young specimens in particular hold on so many stones that they become almost buried. This, together with their small size and habit of living under stones, is a very effective protective device, making them extremely difficult to find. It would appear then, that although this habit may be to some extent a response to increased light intensity, it is also a protective response which is of positive value to the young echinoid.
Evechinus chloroticus is regarded by Mortensen (1943) as a primitive member of the Family Echinometridae, which he thinks represents a less specialized branch derived from the same evolutionary stem as the Family Echinidae. He is not certain of the common ancestor from which these two families have arisen, but thinks it would belong to either the stomopneustids or the phymosomatids. He considers that Evechinus shows primitive characters—namely, the regular hemispherical shape of the test; oligoporous ambulacral plates; and spines of simple structure and only moderate size.
The possession of a single, strongly developed lateral tooth on the blades of the gemmiform pedicellariae is taken by Mortensen (1943) as the distinguishing character which places Evechinus in the Family Echinometridae, while the nature of the larval form and the paired nature of the poison glands are taken as supplementary evidence. This latter character he thinks must indicate a primitive condition, since the single glands found in all the Echinidae have double efferent ducts arising from them, thus giving evidence of an originally paired nature.
In his key to the Family Echinometridae Mortensen (1943) describes the spicules of the tube-feet of Evechinus as “simply bihamate”. Although this superficially appears to be the case, when examined under high magnification small distal projections are seen to be present, rather similar to those described by Mortensen (1943) as present on the spicules of Selenchinus armatus, a form which he regards as closely related to Evechinus. I would suggest, therefore, that the spicules be deleted from the key, which is not invalidated, however, as the character is of supplementary value only.
The apical system of Evechinus conforms to the general echinometrid pattern as described by Mortensen (1943). Attention is drawn to the fact that although he has described the pores of the ocular plates as unusually small they are actually quite wide, approximately of the same order of size as those he figures for Selenchinus armatus. The tendency, which is seen quite frequently in other members of the Echinoidea, for the porous surface of the madreporite to become extended on to the neighbouring genital plates (Lang, 1896), is described in Evechinus, and is apparently unusual in echinometrids, Anthocidaris crassispina being the only form in which such a condition had been noted by Mortensen (1943). He describes the madreporite of echinometrids as conspicuously enlarged, and this is certainly true for Evechinus, so that the tendency to extend the porous surface still further may indicate the continuance of an evolutionary trend.
H. L. Clark (1912, 1925) takes a very different view of the systematic position and ancestry of Evechinus. He has proposed two alternative classifications of the genus, neither of which, however, corresponds to Mortensen's (1943). At first he regarded Evechinus as belonging to the Family Echinidae, of which it represented a specialized form, by virtue of its pseudo-polyporous ambulacral plates, apical system (oculars V and I insert) and its pedicellariae. However, later (1925), after Mortensen (1921) had published his description of the larval form, Clark apparently regarded the genus as too specialized to belong to the Echinidae, and accordingly, although it was only oligoporous, removed it to the Family Strongylocentrotidae,
a group of otherwise characteristically polyporous forms. This is not consistent with his general scheme of classification which is primarily based on the number of elements present in the ambulacral plates. This particular character has been disregarded by Mortensen (1943) as not of primary importance because he thinks multiplication of pores has arisen many times in separate lineages. Evechinus at least would bear this out, in that specimens have been found with occasional polyporous plates among the otherwise oligoporous ambulacral plates. H. L. Clark himself describes such an example. “I have pinned my fatih to the test structure, especially to the essential difference between the triporous and polyporous ambulacra and now I find that in a South African species (Paracentrotus agulhensis) the same ‘adult’ individual may show both kinds!… This is probably due to senescence, but it is perplexing nevertheless.” Although by using Mortensen's (1943) method of classification, which stresses the value of the pedicellariae, this problem is avoided. Nevertheless H. L. Clark (1925) points out an inconsistency in that Mortensen does not use it for the Temnopleuridae. “The conclusion which Dr. Mortensen reached for the Temnopleurids from his study of the pedicellariae of that family coincides with that which I have reached from the study of all the regular Echini—i.e., that while the pedicellariae often afford good specific characters they are not, taken by themselves, reliable as a guide in seeking for the true interrelationships of the species. It does not seem that a character of such uncertain value in the Temnopleuridae can possibly become of ‘prime’ importance in the closely related Echinidae.” The difficulties involved in settling the systematic position of Evechinus chloroticus are thus seen to involve such a wide group of genera as to be far outside the limits of this study to decide, concerned as it is chiefly with description of the anatomy and morphology of but the one form.
However, investigation of the anatomy of Evechinus chloroticus, together with the rather superficial account of Heliocidaris erythrogramma, and comparison with Echinus esculentus, would seem to indicate the two former genera as belonging together in a group apart from Echinus and its allies. The alimentary canal of both Evechinus and H. erythrogramma is voluminous and greatly convoluted, much more so than is generally described in the Echinidae (Bonnet, 1925), particularly the genus Echinus (Chadwick, 1900). The stomach forms long vertical festoons in each radius, which are lacking in Echinus. They are described by Bonnet (1925) as being present in Paracentrotus, which, however, belongs to a different sub-family, the Sub-family Parechininae. The question is raised whether extensive coiling of the gut is a primitive character, upholding Mortensen's (1943) contention that the Echinometridae are less specialized than the Echinidae. The fact that the irregular echinoids which are generally considered high in the echinoderm evolutionary scale, have the alimentary canal following a comparatively simple course (Cuénot, 1948, et al), suggests that this may well be the case.
The shape and structure of the pharynx of Evechinus is very different from that figured by Chadwick (1900) for Echinus, where there are apparently no large radial ridges of connective tissue such as can be seen in Evechinus. There are also small differences in the histology of the alimentary canal in the two forms. The pharynx is apparently more muscular in Echinus (Bather, 1900) than in Evechinus, and there is an opposite arrangement of longitudinal and circular muscle fibres in the oesophagus (Delage and Hérouard, 1903).
Mortensen (1943) himself has drawn attention to the styloid processes borne by the epiphyses of the lantern, which are well developed in both H. erythrogramma and E. chloroticus. He describes them as lacking in the Echinidae, except for a slight indication in Echinus elegans, Psammechinus miliaris and Parechinus angulosus. However, it would be difficult to say whether the epiphysial processes of the echinometrids have been secondarily acquired or those of the echinids secondarily lost.
The apical connection between the axial organ and the stone canal, described by many authors as present in Echinus (Chadwick, 1900, et al.) does not appear to be developed in Evechinus. The well-defined ridge on the apical plates of both H. erythrogramma and E. chloroticus, for the attachment of the wall of the periproctal sinus, is not described for Echinus.
With regard to the nervous system, the apical nerve ring and the radial nerves of the deeper oral system are either absent or only poorly developed in Evechinus. Otherwise the system is of the usual pattern described for echinoids (Lang, 1896, et al.).
In both Evechinus and H. erythrogramma the lacunal system is quite well developed, although in Evechinus, and possibly in H. erythrogramma, the lacunal ring about the top of the oesophagus is of only microscopic size and the amount of haemal tissue in the walls of the gonads very slight. In Echinus esculentus these structures are described by some authors (Cuénot, 1948, et al.) as being well developed. Although the radial haemal canals are quite large where they run on the pharynx and near the mouth, they eventually taper away to nothing at the ambitus. However, this may also be the case with Echinus, as Chadwick (1900) found them impossible to detect in all sections which he cut of the ambulacra. A conspicuous collateral canal is present in both Evechinus and H. erythrogramma and follows the same course as it does in other echinoids from which it has been described (Bonnet, 1925). Of the members of the Echinidae which Bonnet investigated he found it to be present in Echinus and Psammechinus, but lacking in Paracentrotus. The internal marginal canal is muscular in Evechinus, which is apparently not the case in Echinus.
The ambulacral system, axial organ and coelomic cavities are of the usual echinoid type (Lang, 1896,et al.) and show nothing remarkable. The tube-feet of the ambulacral system show the only small amount of differentiation characteristic of the regular echinoids (Cuénot, 1948).
The great coalescence of the gonads in Evechinus is apparently not of taxonomic significance. Mortensen (1943) describes the condition as being fairly general in the Family Echinometridae, but those of Heliocidaris erythrogramma are quite small and remain distinct, although they are elongated to extend from the apex to the lantern in the same way as do those of Evechinus. In the Family Echinidae there is apparently the same inconsistency, for, although the gonads in general are described by Mortensen (1943) as remaining separate, those of Psammechinus and Parechinus are strongly coalesced, and they may apparently even become so in occasional specimens of Echinus esculentus.
The appearance of the gonad in young specimens of Evechinus suggests that the gonoduct is the first part of the gonad to appear and that from it the follicles, in which the genital products are formed, are subsequently budded. It is possible that the gonads of all echinoids may arise in this way.
The difference in colour of the mass of released sexual products, and the size of the genital papillae are the only characters by which the sexes of Evechinus can be distinguished, apart from microscopic identification of gonad samples. A similar difference in papillae between sexes has been noted in H. erythrogramma. The papillae of Evechinus and H. erythrogramma are almost identical, and differ in form from those of Echinus (Swann, 1953). There is no widening of the genital pores in the females of either Evechinus or H. erythrogramma. This is as would be expected in Evechinus where the eggs are small and the larvae of indirect development (Mortensen, 1921). However, in H erythrogramma the egg is five times larger than that of E. chloroticus and the development direct (Mortensen, 1921). So it is surprising that both male and female pores should be only of the same order of size as those of Evechinus.
From this discussion it may be seen that the anatomical differences between Evechinus, Heliocidaris and Echinus are very slight, bearing out H. L Clark's observation that “the relationship with each family is so close that it is impossible to fix a natural boundary, passing which no exceptions will be found”. However, such differences as there are appear to uphold the view that Evechinus and Heliocidaris should be placed together in a group apart from Echinus and its allies in the Echinidae, whether that group be as H. L. Clark (1925) proposes, the Family Strongylocentrotidae, or as Mortensen (1943) contends, the Family Echinometridae.
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“Ngatawhai”, No. 3 R.D, Masterton.
The Spiders of the Family Symphytognathidae
Otago Museum, Dunedin, New Zealand
[Received by the Editor, April 21, 1958.]
The status of the families Symphytognathidae, Anapidae, Textricellidae and Micropholcommatidae and the genera Mysmena and Lucharachne is discussed, and it is proposed to group all of these spiders into a single family for which the earliest name is Symphytognathidae. The affinities of the family are discussed, and it is concluded that it was derived from the Argiopidae; and it is suggested that the resemblance which some genera show with the Theridiidae in structure and habits is the result of convergence. The web, where it is known, indicates that the basic structure is an orbweb, but that in a number of species this has been modified to give the appearance of webs typical for the Theridiidae and Linyphiidae. New records are given for a number of previously described species, and two new genera and twenty-eight new species are established. The structure of the respiratory system within the family is discussed, and it is concluded that the different systems represented have at the most generic significance.
The spiders included in the Symphytognathidae are all minute, ranging in body length from about 0.5 mm to 2.00 mm. Because of their small size and the cryptozoic life they lead in leafmould and moss, they have been rarely found in the past and are generally poorly represented in collections. However, over the last few decades sufficient numbers of these spiders have been collected and recognised to permit more conclusive studies to be made. Most of the specimens recorded in the present paper have been obtained over the last ten years from leafmould and moss by the use of Salmon's modification of the Berlese Funnel.
The family Symphytognathidae was established by Dr. V. V. Hickman in 1931 for the minute Tasmanian spider Symphytognatha globosa. The family was based on a number of unusual characters, of which the most important were the absence of lungbooks, the anterior spiracles leading into tracheae, the absence of female palps, and the fusion of the chelicerae along the midline. Petrunkevitch (1933) in his monumental study on the classification of spiders based on a study of their internal anatomy, pointed out that, in addition to the lack of lungbooks, the Symphytognathidae shared a number of internal characters with the Leptonetidae and Caponiidae, and he therefore placed these three families in a separate sub-order, the Apneumonomorphae. Fage (1937), after examining the respiratory system of a number of the spiders placed by Simon (1895) in the group Anapeae (Argiopidae), pointed out that all of the genera in this group which he was able to examine, with the exception of Tecmessa, were without lungbooks and should be in his opinion placed in the family Symphytognathidae, and he suppressed the family Anapidae established two years earlier by Kratochvil (1935) for these spiders. This conclusion has been followed by all subsequent authors.
Hickman, in the course of his series of papers on the spiders of Tasmania, established two further families of apneumone spiders, Micropholcommatidae (1944) and Textricellidae (1945), which he placed in the sub-order Apneumonomorphae with the Symphytognathidae, Telemidae and Caponiidae.
After studying the large series of spiders now available from New Zealand, Australia, New Guinea and the Pacific Islands, and the collection of these spiders from North and South America in the American Museum of Natural History, New York, I have concluded that the families Symphytognathidae, Micropholcommatidae and Textrcellidae, with the genera Mysmena and Lucharachne could well be placed in a single family, for which the oldest available name is the Symphytognathidae.
In spite of our increasing knowledge of the structure and habits of these spiders the relationship of this family to other spiders still remains in doubt. The genera included in the wider interpretation of the family adopted in this paper could be grouped equally well on morphological grounds to demonstrate close affinity with either the Argiopidae or the Therdiidae. Opinion in the past has been divided in the main between these two alternatives. Simon (1895) placed his group Anapeae at the end of the Argiopidae, indicating affinity with the orbweb spiders, while Berland (1924) considered that the group should be placed in the Theridiidae. Fage (1937), while following Simon's placing of the group, pointed out that only future study would resolve the question of whether the family had evolved directly from either the Argiopidae or Theridiidae or originated from stock common to both of these families. I am inclined to the view that the family has been derived from the Argiopidae or at least has evolved from a stock common with the Argiopidae. The fact that a number of genera construct typical orbwebs—Risdonius (Hickman, 1938), Chasmocephalon (Hickman, 1946), Patu (Marples, 1956)—in my opinion strongly supports this view. It is most difficult to conceive the separate development of an orbweb in a form identical with that of typical argiopid spiders, whereas degeneration from an orbweb could easily lead to webs having the appearance of sheet or tangle webs. Textricella constructs small sheet webs which look like those of the Micryphantidae while the webs of Micropholcomma are tangle webs such as are found in the Theridiidae. Archer (1946) reports that North American species of Mysmena constructs a sheet web, but the statement made by Marples (1955) after carefully studying Tamasesia acuminata, a species which is transferred to Mysmena in the present paper, seems significant. He states: “The web is extremely delicate. It consists of a set of threads radiating in all directions from a centre where the spider sits. The space between the radials is filled with the threads of sticky silk, so fine that the droplets can only be seen under the microscope, and the whole occupies a volume roughly 1.5–2 cm across. When spinning the spider keeps going quickly out along different radials. Apparently it attaches a thread to a radial and carries the other end to the centre and out along another radial to attach it there. The web is built from the periphery inwards. Though the threads are not regularly arranged, the general impression is of an orb web in three dimensions.” If we were attempting to bridge the gap between the typical orbwebs found in Chasmocephalon, Risdonius and Patu and the type of web found in Micropholcomma, the web of Mysmena acuminata provides a perfect example. With only slight modification this type of web would lose all resemblance to an orbweb, and would then be in the form found in Micropholcomma. With reference to the development of a sheet web from an orbweb, I might quote Marples' (1951) reference to the web of Patu samoensis, where he states: “They consisted of a very fine horizontal sheet with very regular meshes. The sheet was an irregular polygon some six centimetres long, and an oblique thread extended upwards from the sheet between one and two centimetres from one end. The threads of the sheet radiated from a point of attachment of the oblique thread, but it was a sheet and not an orb web.” Later observations, however (Marples, 1955) demonstrated that this web is initially an orbweb of very fine mesh, and that subsequent tangling of the threads or the addition of further threads gives it the appearance of a sheet web. During a brief stay in Fiji in 1956 I was able to examine the web of the very closely related species Patu vitiensis. The webs, which are from 3 to 5 centimeties in width, were on tree trunks, where they were placed horizontally. The threads were extremely fine and
closely spaced, but after treatment with talc the web was found to be a perfect orb, with the sticky spiral lines closely spaced, and it does not appear that in this species the regular structure is subsequently modified as in samoensis.
Symphytognatha is reported by Hickman (1931) to construct an irregular web like that of Theridion, in which the spider rests in an inverted position. In view of the very close morphological relationship of this genus to Patu it would be of considerable interest if the method of web construction were to be closely studied to see if there is any evidence for this web being a degenerate orbweb.
The basic work for this paper was carried out at the Museum of Comparative Zoology at Harvard University and the American Museum of Natural History, New York, while the author held a Fulbright Research Scholarship. I wish to express my deep appreciation to both of these institutions for assistance in many ways, and to the United States Educational Foundation for granting the research scholarship which made my visit possible. I am deeply indebted to Dr. Willis J. Gertsch, of the American Museum of Natural History, and Dr. Herbert Levi, of the Museum of Comparative Zoology for much information and advice, and to Dr. V. V. Hickman for specimens of Tasmanian spiders, and encouragement over many years. This paper would not have been possible without the numerous specimens which have been collected by Dr. T. E. Woodward, of the University of Queensland, and I wish to express my deep gratitude for these and other spiders which he has forwarded to me for examination over the last seven years. I am also much indebted to Professor B. J. Marples for information on web structure and many helpful discussions during the final preparation of the manuscript, and to the numerous individuals mentioned in the text who have assisted in collecting specimens.
|1931.||Symphytognathidae Hickman. Proc. Zool. Soc. London. p. 1328.|
|1935.||Anapidae Kratochvil. Act. Soc. Sc. Natur. Moravicae, 9 (12).|
|1944.||Micropholcommatidae Hickman. Pap. Proc. Roy. Soc. Tasm. p. 183.|
|1945.||Textricellidae Hickman. Trans. Conn. Acad. Arts Sc. 36, p. 136.|
|1956.||Tamasesidae Marples. J. Linn. Soc. Zool. 42 (287), p. 476.|
Cribellum and calamistrum wanting. Colulus present (except in Symphytognatha and Patu). Six spinnerets. Lungbooks usually wanting, when present somewhat atypical in form. Anterior spiracle usually leading into tracheal tubes which sometimes supply both abdomen and cephalothorax, but often only abdomen. Two posterior spiracles, one or none. Posterior spiracles when present supplying tracheal tubes to abdomen only, both abdomen and cephalothorax or cephalothorax only. Eight eyes, six eyes or four eyes. Lateral eyes always contiguous. Carapace usually high. Clypeus high, vertical. Labium fused, Maxillae converging. Palp in female without claw, often reduced in length and in the number of segments, sometimes completely absent. Legs prograde, without spines (except secondary spines on legs of males) or scopulae. Claw tufts wanting. Tarsus longer than metatarsus. Tarsal drum present. Three claws. Trichobothria few, two or three on tibia, one on metatarsus of first three legs, none elsewhere. Type genus Symphytognatha Hickman 1931.
The Symphytognathidae as defined above presents a number of characters which clearly separate it from other families. The relative lengths of the tarsus and metatarsus are very characteristic. The tarsus is usually much longer than the metatarsus, which is the reverse of the situation in practically all other spiders. In a few forms which I have included in this family (Mysmena) at least one pair of legs shows this character, while the lengths of these segments in other legs is subequal. Pholcomma, a genus usually placed in the Theridiidae, also shows this character to a less marked degree, but possesses a claw on the female pedipalp. I have not placed this genus into the Symphytognathidae although it possesses a number of other characters which might justify this action. An examination of a New Zealand species of Pholcomma shows that the lungbooks are normal. Levi (1956) recently
established a genus Archerius for a North American spider in which the tarsi are longer than the metatarsi and which possessed other characters which indicate that it could probably be placed within the Symphytognathidae. All of these spiders possess a tarsal drum, but until this structure is specifically looked for over a wider range of spiders it is not known how much significance it has in phylogeny. The loss of the claw from the female pedipalp seems to be common to all genera, while there is also a tendency to a reduction in the length and number of segments culminating in the complete loss of this appendage in several genera.
The original number of eyes must have been eight, but there is a tendency for the anterior median eyes to be reduced in size or absent, and in one genus the posterior median eyes are also absent (Anapistula Gertsch). In four genera (Pseudanapis and Anapistula, Textricella and Pseudanapis) I have grouped together spiders with different numbers of eyes where other characters have indicated a close relationship. The lateral eyes in all genera are contiguous, and except in Mysmena are well separated from the median eyes.
The carapace of both males and females is usually elevated, and this is probably a primitive family character. In Anapistula, however, the carapace is not conspicuously elevated, while in Mysmena it appears as a dimorphic character shown only in the males. I consider that this represents a regression rather than an indication that the elevated form has been developed within the family. The presence of an elevated carapace in both sexes is of considerable interest and represents a condition fundamentally different from that found in other families (Argiopidae including Landana, Theridiidae, Linyphiidae, Micryphantidae) where only the male possesses this character. The only other family which does possess this character in the same form is the Archaeidae, which shares other characters with the Symphytognathidae and in my view is closely related to it.
The respiratory system of these spiders is discussed at greater length elsewhere in this paper, but it is evident that the ancestral forms of this family must have possessed two anterior spiracles leading into lungbooks and two posterior spiracles leading into tracheae. Within the family there is great variation in the form of the respiratory system, and it appears evident that this variation is at the most of generic significance.
List of Genera and Species
Symphytognatha Hickman 1931
Type Species Symphytognatha globosa Hickman 1931 (Tasmania)
Patu Marples 1951
Type Species Patu vitiensis Marples 1951 (Fiji)
Patu samoensis Marples 1951 (Samoa)
Patu marplesi n.sp. (Samoa)
Patu woodwardi n.sp. (New Guinea)
Anapistula Gertsch 1941
Type Species Anapistula secreta Gertsch 1941 (Panama)
Anapistula boneti Forster 1958 (Mexico)
Anapistula australia n.sp. (Australia)
Anapis Simon 1895
Type Species Anapis hetschki (Keyserling) 1883 (Brazil)
Anapis hamigera Simon 1897 St. Vincent (Venezuela)
Anapis keyserlingi Gertsch 1941 (Panama)
Anapis mexicana Forster 1958 (Mexico)
Anapogonia Simon 1905
Type Species Anapogonia lyrata Simon 1905 (Java)
Epecthinula Simon 1903
Type Species Epecthinula minutissima Simon 1903 (Jamaica)
Chasmocephalon Cambridge 1889
Type Species Chasmocephalon neglectum Cambridge 1889 (West Australia)
Chasmocephalon minutum Hickman 1944 (Tasmania)
Chasmocephalon armatum Forster 1944 (New Zealand)
Crozetulus Hickman 1939
Type Species Crozetulus minutus Hickman 1939 (Crozet Is.)
Pseudanapis Simon 1905
Type Species Pseudanapis paroculus (Simon) 1899 (Sumatra, Java)
Pseudanapis relcta Kratochvil 1935 (Dalmatia)
Pseudanapis algerica Simon (Algeria)
Pseudanapis insolitus Berland 1924 (New Caledonia)
Pseudanapis burra n.sp. (Australia)
Pseudanapis octocula n.sp. (Australia)
Pseudanapis darlingtoni n.sp. (Australia)
Pseudanapis grossa n.sp. (New Guinea)
Pseudanapis wilsoni n.sp. (New Guinea)
Pseudanapis aloha n.sp (Hawaii)
Pseudanapis spinipes (Forster) 1951 (New Zealand)
Pseudanapis insula (Forster) 1951 (New Zealand)
Risdonius Hickman 1939
Type Species Risdonius parvus Hickman 1939 (Tasmania)
Risdonius conicus (Forster) 1951 (New Zealand)
Anapisona Gertsch 1941
Type Species Anapisona simoni Gertsch 1941 (Panama)
Anapisona gertschi Forster 1958 (Maxico)
Anapisona kartabo Forster 1958 (British Guiana)
Mysmena Simon 1894
Type Species Mysmena leucoplagiata (Simon) 1879 (France)
Mysmena conica Simon 1894 (Algeria)
Mysmena guttata (Banks) 1895 (United States)
Mysmena cymbia Levi 1956 (Florida)
Mysmena incredula (Gertsch and Davis) 1936 (Southern United States, central America)
Mysmena guianaensis Levi 1956 (British Guiana)
Mysemena ixlitla Levi 1956 (Mexico)
Mysmena saltuensis Simon 1885 (Ceylon)
Mysmena illectrix Simon 1895 (Philippines Is.)
Mysmena rotunda (Marples) 1955 (Samoa)
Mysmena acuminata (Marples) 1955 (Samoa)
Mysmena samoensis (Marples) 1955 (Samoa)
Mysmena phyllicola (Marples) 1955 (Samoa)
Mysmena vitiensis n.sp. (Fiji)
Mysmena conica n.sp. (New Guinea)
Textricella Hickman 1945
Type Species Textricella parva Hickman 1945 (Tasmania)
Textricella fulva Hickman 1945 (Tasmania)
Textricella luteola Hickman 1945 (Tasmania, Australia)
Textricella hickmani n.sp. (Tasmania)
Textricella complexa n.sp. (Australia)
Textricella lamingtonensis n.sp. (Australia)
Textricella aucklandica Forster, 1955 (Auckland Is.)
Textricella nigra n.sp. (New Zealand)
Textricella insula n.sp. (New Zealand)
Textricella signata n.sp. (New Zealand)
Textricella vulgaris n.sp. (New Zealand)
Textricella antipoda n.sp. (New Zealand)
Textricella mcfarlanei n.sp. (New Zealand)
Textricella propinqua n.sp. (New Zealand)
Textricella salmoni n.sp. (New Zealand)
Textricella plebeia n.sp. (New Zealand)
Textricella scuta n.sp. (New Zealand)
Textricella pusilla n.sp. (New Zealand)
Textricella tropica n.sp. (New Guinea)
Micropholcomma Crosby and Bishop, 1927
Type Species Micropholcomma caeligenus Crosby and Bishop 1927 (Australia)
Micropholcomma longissima (Butler 1932) (Australia)
Micropholcomma parmata Hickman 1944 (Tasmania)
Micropholcomma mira Hickman 1944 (Tasmania)
Micropholcomma bryophila (Butler) 1932 (Australia)
Type Species Pua novazealandiae n.sp. (New Zealand)
Type Species Parapua punctata n.sp. (New Zealand)
Lucharachne Bryant 1940
Type Species Lucharachne tibialis Bryant 1940 (Jamaica)
Lucharachne palpalis Krauss 1955 (Honduras)
Genus Textricella Hickman, 1945
Textricella, Hickman 1945, Trans. Conn. Acad. Arts. Sc. 36: 1936.
Type species (original designation) Textricella parva Hickman 1945. Minute spiders ranging from 0.7 mm to 1.2 mm in body length. Carapace high, usually from one-half to slightly more than the width of the carapace, ascending steeply in front to the eyes, cephalic portion more or less level on top, slightly rounded and usually highest near the level of the third pair of coxae from where it slopes down to the posterior margin. There are a pair of long hairs on the posterior portion of the head region and a single row down the median surface. Apart from these hairs and a few smaller hairs about the eyes the carapace is glabrous. Fovea absent. Six or eight eyes placed in two rows. AME when present smallest, separated from each other by less than their diameter. Lateral eyes contiguous. Median ocular quadrangle much shorter in front than behind. Clypeus high, from three to five times the diameter of an ALE.
Chelicerae vertical, lateral condyles absent. A blunt apophysis is sometimes present on the retrolateral surface of the chelicerae of the males. Teeth differing between sexes. Females with a single tooth on the retromargin and from 4–5 on promargin. Males with 2–5 teeth on retromargin and from 2–3 stout and rod-lilke bristles on the promargin. There is a row of five ciliate setae on the retrolateral surface near the fang furrow in both sexes, and two stout setae, one smooth and one ciliate, placed on a small prominence on the distal prolateral surface near the base of the fang. Labium wider than long and fused to the
sternum. Maxillae directed across the labium, with an apical scopula and a definite serrula along the anterior margin. Sternum granulate, convex, slightly longer than wide, sub-oval but emarginate at the bases of the coxae, broadly obtuse posteriorly between coxae 4 which are separated by from one to one and a-half times their diameter.
Legs short, relative lengths 126.96.36.199 or 188.8.131.52, covered with fine smooth hairs but lacking spines, scopulae or claw tufts. Males of some species with a stout bristle on the distal prolateral surface of the tibia of the first pair of legs. Tarsi much longer than metatarsi. A tarsal drum present on the tarsi of both legs and palp in both sexes, situated at approximately one-fifth of the length of the segment from the base in legs 1 and 2 and one-tenth on legs 3 and 4. Trichobothria present on all tibiae, 2.1 on legs 1–3, 184.108.40.206 on leg 4, metatarsus 1–3 with single trichobothrium on median surface. Three claws, superior homogeneous, with from 4–6 small teeth reduced in number on legs 3 and 4, inferior claw with a single ventral tooth. Female palp small, without claw. Male palp with patella processes, tibia usually flattened. Bulb relatively simple, conductor sometimes absent. Abdomen oval, clothed with small smooth setae usually rising from small sclerotic plates. Epigastric plates present in both sexes surrounding the petiolus and usually extending back to the epigastric groove. A dorsal plate is often present in the male. Six spinnerets, terminal, compact. Colulus large, with two prominent setae.
Colour fairly uniform, cephalothorax and appendages reddish or orange-brown, abdomen pale yellow, grey, creamy-white or black.
The respiratory system has been described for the three Tasmanian species parva, fulva, and luteola by Hickman (1945) as lacking a posterior tracheal spiracle, book-lungs wanting, with two tracheal spiracles, one on each side in the epigastric groove from which tracheal tubes extend into the abdomen but do not pass into the cephalothorax. The respiratory system of a large proportion of the New Zealand species where the slide and KOH preparations have been studied indicates that these species have in general a similar respiratory system.
The New Zealand species occupy a similar habitat to that recorded by Hickman for the Tasmanian species. They are found in moss on the forest floor and on the trunks of trees in situations which remain moist the year round. The spiders construct small sheet webs which are similar in appearance to those of the Micryphantidae. There does not seem to be any indication of a strong seasonal variation in the maturity of the spiders as far as the New Zealand species are concerned as they may be found mature in numbers at any time of the year.
Species differentiation is based mainly on the structure of the palp of the males and the internal genitalia of the female. The males of a number of species show secondary modifications in the presence of a spine on the first leg and a tubercle or swelling on the chelicerae.
Until now the recorded distribution of this family has been Tasmania and the Auckland Islands. The material examined during the preparation of the present paper extends this distribution to include New Zealand, the East Coast of Australia, and New Guinea.
Further records for the three species described by Hickman (1945) from Tasmania are listed below, and the female internal genitalia which were not figured by Hickman are illustrated for comparison with other species.
Textricella parva Hickman 1945. Fig. 1.
Previous Record. Tasmania: Cascades.
Present Record. Tasmania: Russell Falls, Mount Field, ex moss, February 12, 1955. T. E. Woodward.
Textricella fulva Hickman 1945. Fig. 2.
Previous Record. Tasmania: Mount Wellington.
Present Record. Tasmania: Lake Dobson Road, 2,500ft. Mount Field, National Park, January 7, 1955, T. E. Woodward.
Textricella luteola Hickman 1945. Fig. 3.
Previous Record. Tasmania: Mount Wellington.
Text-fig. 1.—Fig. 1—Textricella parva, female internal genitalia. Fig. 2—Textricella fulva, female internal genitalia. Fig. 3—Textricella luteola female internal genitalia. Figs. 4–6—Textricella complexa n.sp. Fig. 4—Prolateral view of male palp. Fig. 5—Retiolateral view of male palp. Fig. 6—Female internal genitalia.
Present Records. New South Wales: National Park, August 24, 1952, T. E. Woodward; Katoombah, Blue Mountains, February 26, 1953, T. E. Woodward; Queensland: Lamington National Park, ex leafmould, rain forest, June 1, 1955, T. E. Woodward; Mount Clunie, east ridge, ex leafmould, April 15, 1953, T. E. Woodward; Mount Tambourine, east side below Eagle Point, May 8, 1953, T. E. Woodward; Mount Tambourine, ex leafmould, July 18, 1954, T. E. Woodward; Blackbut, ex leafmould, September 10, 1953, T. E. Woodward; Mt. Tambourine, north side, near Curtis Falls, May 8, 1953, T. E. Woodward; Binna Burra, ex leafmould, July 20, 1952, September 2, 1954, T. E. Woodward; Camp Mount district, Sanford Valley, October 25, 1952, T. E. Woodward; between Landsborough and Caloundra turnoff, ex leaf debris, in Casuarina and Eucalyptus, October 4, 1953, E. N. Marks.
Textricella complexa n.sp. Figs. 4–9.
Male. Measurements: Carapace—Length, 0.56; width, 0.50; height, 0.44 Abdomen—Length, 0.71; width, 0.54.
Colour. Carapace, sternum and abdominal scutes. orange-brown. Legs, pale yellow.
Eyes (Fig. 9). Eight: Ratio of AME: ALE: PME: PLE = 5:10:9:10. When viewed from in front the anterior row is almost straight, while the posterior row is recurved. AME separated from each other by a distance equal to, and from the ALE by one and a-half times the diameter of an AME. PME separated from each other and the PLE by a distance equal to one and a-half times the diameter of an AME. Median ocular quadrangle wider behind than in front in the ratio of 27:15, wider behind than long in ratio of 27:24 Clypeus vertical, height equal to five times the diameter of an AME.
Chelicerae (Fig. 7). There is a strong protuberance present on the mid prolateral surface. Promargin with three pegs, retromargin with five teeth, of which the median three are fused at the base.
Palp (Figs. 4–5). General form very similar to parva.
Legs 1–4.2.3. Distal prolateral surface of the tibia of leg 1 with strong spines.
Abdomen. Both dorsal and ventral scutes present. Ventral scute large, extending over three-fifths of the ventral surface. Six spinnerets with colulus, encircled by sclerotic ring.
Female. Measurements: Carapace—Length, 0.50; width, 0.21; height, 0.31. Abdomen—Length, 0.79; width, 0.63.
Abdomen bluish-grey with numerous small pale yellow patches. Chelicerae with a single tooth on promargin and five on the mid-retromargin of which the distal four decrease in size distally and are fused at the base (Fig. 8). Epigynum with two pairs of lobes at about the mid-surface of the ventral plate, under which the external openings of the genitalia are situated. Receptaculum seminis at the side of the petiolus with the fertilisation duct running straight back to the posterioi margin of the ventral scute (Fig. 6).
Types. Holotype male, allotype female, paratypes. New South Wales: National Park, ex leafmould August 24, 1952, T. E. Woodward. Holotype and allotype in Queensland Museum, paratypes Otago Museum.
Text-fig.. 2.—Figs. 7–9—Textricella complexa n.sp. Fig. 7—Prolateral view of male chelicera. Fig. 8—Prolateral view of teeth and fang of female chelicera. Fig. 9—Carapace and chelicerae from in front of male. Figs. 10–13—Textricella nigra n.sp. Fig. 10—Retrolateral view of male palp. Fig. 11—Prolateral view of male palp. Fig. 12—Female epigynum and internal genitalia. Fig. 13—Retrolateral view of teeth and fang of male chelicera.
Remarks. Textricella complexa is closely related to T. parva Hickman from Tasmania, but it may be easily separated by the structure of the male palp, the female epigynum and the internal genitalia. There is a bilobed structure on the midventral surface of the ventral scute of the female of complexa in place of the single curved ridge in parva, while the receptaculum extends forward so that it is situated at the side of the petiolus.
Textricella nigra n.sp. Figs. 10–13.
Male. Measurements: Carapace—Length, 0.56; width, 0.39; height, 0.42. Abdomen—Length, 0.65; width, 0.46.
Colour. Carapace and sternum dark brown, heavily shaded with black. Abdomen dark bluish-grey. Appendages pale brown.
Eyes. Eight. Ratio of AME:ALE:PME:PLE = 2:4:3:4 AME separated from each other by a distance equal to 7/10, and from the ALE by a distance equal to, the diameter of an AME. Lateral eyes contiguous. PME separated from each other and from the PLE by a distance equal to one and a-half times the diameter of an AME. Median ocular quadrangle wider behind than in front in proportion of 45:27, wider behind than long in ratio of 45:33. Clypeus vertical, height equal to seven times the diameter of an AME.
Chelicerae (Fig. 13). Without lobes. Promargin with three pegs, retromargin with three teeth.
Palp (Figs. 10–11). Patella with a strongly denticulate, spinous projection on the distodorsal surface and a curved plate which originates from the disto-ventral surface. Tibia spatulate, without processes. Bulb simple, embolus stout, gently curved, conductor absent.
Legs 220.127.116.11. There is a slender spine on the distal prolateral surface of the femur of leg 1.
Abdomen. Dorsal scute absent. Mammillary ring present.
Female. Measurements: Carapace—Length, 0.48; width, 0.39; height, 0.42. Abdomen—Length, 0.65; width, 0.56.
Chelicerae with a single tooth on the proximal promargin and four on the mid retromargin of which the distal and the proximal are the largest. Epigynum in the form of a raised plate covering a broad chamber. The internal genitalia are shown in Fig. 12.
Types. Holotype male, allotype female and paratypes. Little Barrier Island, Summit Track, 2,000–2,300 feet ex moss, C. Parkin. (Holotype, allotype, Canterbury Museum, paratypes Otago Museum, Dominion Museum.)
Record. Te Aroho Mountain, 3,000–3,100 feet, ex moss on tree trunks, May 6, 1946, J. T. Salmon; Tararua Range, Tirotiro, B. A. Holloway.
Remarks. The complex structure of the patella of the male palp and the wide vestibule to the female epigynum places this species apart from all other known New Zealand species. The specimens from Tirotiro, in the Tararua Ranges, which
are all males, show slight differences from the Te Aroho and Little Barrier material in that the disto-dorsal process on the patella of the palp is shorter and the embolus is relatively longer and more slender.
Textricella hickmani n.sp. Figs. 14–19.
Male. Measurements: Carapace—Length, 0.56; width, 0.44; height, 0.44. Abdomen—Length, 0.58; width, 0.48.
Colour. Carapace dark reddish brown with a black patch on the posterior surface of the head. Sternum dark brown with black shading. Appendages uniform yellow brown. Abdomen steel blue with numerous small white patches.
Eyes (Fig. 15). Eight. When viewed from in front both rows appear procurved, posterior row more strongly. Ratio of AME:ALE:PME:PLE = 5:10:6:15. The AME are separated from each other by their diameter and from the ALE by twice this distance. Laterals contiguous. PME separated from each other by twice and from the PLE by three times the diameter of an AME. Ocular quadrangle wider behind than in front in the ratio of 22:15. Clypeus vertical, height equal to six times the diameter of an AME.
Chelicerae. Pronounced tubercle present. Promargin with three pegs, two proximal, one distal, retromargin with from 2–3 small teeth.
Legs 18.104.22.168. Femur of leg 1 with a long slender spine on the distal prolateral surface as shown in Fig. 19.
Palp (Fig. 14). The tarsus and the bulb appear to be carried twisted back so that the bristles on the distal surface of the tarsus are projecting over the denticulate surface of the distal portion of the patella. The embolus is stout and lightly coiled with the tip resting behind the process from the patella, where it is held in place by two stout setae.
Abdomen. Dorsal scute absent. Plates at the base of hairs weakly developed. Spinnerets with sclerotic ring.
Female. Measurements: Carapace—Length, 0.67; width, 0.48; height, 0.33. Abdomen—Length, 0.84; width, 0.60.
Similar in general structure to male. Chelicerae with a single tooth on the mid promargin and six (1.3.2) on the retromargin (Fig. 18). The internal genitalia are compact (Fig. 15). The external openings lead into a cup-shaped receptaculum, which is followed by a convoluted portion before narrowing to the fertilisation duct, which is twisted around the outer margin to reach the posterior margin of the epigastic groove at the inner level of the receptacula.
Types. Holotype male, allotype female, paratypes. Tasmania: Mount Wellington, ex moss from near O'Grady's Falls, January 29, 1955, T. E. Woodward. (Holotype, allotype, Queensland Museum, paratypes Otago Museum, collection Dr. V. V. Hickman.)
Remarks. This species is closely related to Textricella luteola Hickman with which it is sympatric in Tasmania. It is clearly separated from luteola by the structure of the male palp and the internal genitalia of the female. I have much pleasure
Text-fig. 3.—Figs. 14–19—Textricella hickmani n.sp. Fig. 14—Retrolateral view of male palp. Fig. 15—Internal genitalia of female. Fig. 16—Carapace and chelicerae of male from in front. Fig. 17—Prolateral view of male chelicera. Fig. 18—Prolateral view of female chelicera. Fig. 19—Distal surface of femur and patella, leg 1 of male showing spine.
in naming this species after Dr. V. V. Hickman, who first established the genus to which it belongs, in some recognition of the great advances he has made in the study of the spider fauna of Tasmania and Australia.
Textricella lamingtonensis n.sp. Figs. 20–22.
Male. Measurements: Carapace—Length, 9.65; width, 0.48; height, 0.44. Abdomen—Length, 0.67; width, 0.51.
Colour. Carapace dark brown with black shading on posterior surface of the head. Sternum brown with black shading. Abdomen bluish-grey with small pale spots.
Eyes. Eight, both rows slightly recurved when viewed from in front. Ratio AME:ALE:PME:PLE = 6:10:9:10. AME separated from each other by ¼ of their width and from the ALE by a distance equal to 1½ times the diameter of an AME and from the PLE by slightly more than this distance. Median ocular quadrangle wider behind than in front in ratio of 9:5 and wider behind than long in ratio of 9:8. Clypeus vertical, height equal to 4½ times width of an AME.
Chelicerae (Fig. 22). Stout, vertical, without boss. Promargin with two distal pegs, retromargin with five teeth, of which three are contiguous.
Palp (Fig. 20). Patella with single typical knobbed process. Tibia flattened. Bulb simple with short stout conductor and embolus surrounded by small denticles.
Legs. 22.214.171.124, without secondary spine.
Abdomen. Dorsal scute lacking, ventral scute extending back to the epigastric groove. Spinnerets surrounded by a distinct sclerotic ring.
Female. Measurements: Carapace—Length, 0.63; width, 0.46; height, 0.33. Abdomen—Length, 0.69; width, 0.60.
Colour and general structure as in male. Chelicerae with two promarginal and five retromarginal teeth. Internal genitalia simple, as shown in Fig. 21.
Types. Holotype male, allotype female and paratypes, S. Queensland. Lamington National Park, ex leafmould, rain forest, June 1, 1955, T. E. Woodward. (Holotype, allotype, Queensland Museum, paratypes Otago Museum.)
Remarks. Of the five species now described from Tasmania and Australia, this is the only species which shows the simple structure of male and female genitalia characteristic of most of the New Zealand species. The form of the male and female genitalia clearly separates it from all New Zealand species.
Textricella insula n.sp. Fig. 23.
Male. Measurements:· Carapace—Length, 0.46; width, 0.35; height, 0.33. Abdomen—Length, 0.75; width, 0.60.
Colour. Carapace and abdominal scutes dark golden brown, appendages yellow brown.
Eyes. Eight. Ratio of AME:ALE:PME:PLE = 5:20:11:20. AME separated from each other by a distance slightly less than the diameter of an AME and from the ALE by twice this distance, PME separated from each other by twice and from the PLE by three times the diameter of an AME. Median ocular quadrangle wider behind than in front in ratio of 33:14, while the ratio of width behind to length is 33:24.
Clypeus vertical, height equal to six times the diameter of an AME.
Chelicerae. Without boss. With two pegs on promargin and five teeth on retromargin. Palp (Fig. 23). There is a distal lobe on the patella in addition to the usual knobbed process. Bulb simple with slender curved embolus, conductor straight and slender.
Legs 126.96.36.199 without secondary spines.
Abdomen. Both dorsal and ventral scutes well developed. Mammillary ring present.
Types. Holotype male and paratype male. Solander Island, ex leafmould, July 20, 1948, C. Lindsay. (Holotype male, Dominion Museum, Paratype male, Canterbury Museum.)
Remarks. Close to T. signata from Canterbury and Westland, but separated from this species by the structure of the male palp and differences in the spacing of the eyes.
Textricella signata n.sp. Figs. 24–25.
Male. Measurements: Carapace—Length, 0.58; width, 0.42; height, 0.33. Abdomen—Length, 0.63; width, 0.48.
Colour. Cephalothorax and abdominal scutes deep golden brown; appendages paler yellow brown.
Eyes. From in front the anterior row appears slightly recurved, while the posterior row is more strongly recurved. Ratio of AME:ALE:PME:PLE = 4:20:15:20. AME separated from each other by twice and from the ALE by 2 ½ times, the diameter of an AME. The PME are separated from each other and from the PLE by a diameter of an AME. Median ocular quadrangle wider behind than in front in ratio of 50:20 and wider behind than long in ratio of 50:29. Clypeus equal to six times the diameter of an AME.
Chelicerae. Without secondary processes. Promargin with three pegs, retromargin with two teeth.
Palp (Fig. 24). Very similar in appearance to insula but with the knobbed process on patella more proximal in position. The conductor appears to be absent.
Legs. 188.8.131.52, without secondary spines.
Abdomen. Both dorsal and ventral scutes well developed. Spinnerets enclosed by sclerotic ring.
Female. Measurements: Carapace—Length, 0.54; width, 0.44; height, 0.33. Abdomen—Length, 0.77; width, 0.65.
The abdomen is grey, without dorsal scute but with definite ring surrounding the spinnerets. Internal genitalia as in Fig. 25, with a sclerotic strip posteriorly. Chelicerae with a single tooth on the promargin and three on the retiomaigin.
Types. Holotype male, allotype female and paratypes. Canterbury: Lake Janet, August 1, 1949, R. R. Forster. Paratypes, same locality, August 28, 1951, J. S. Dugdale. (Holotype, allotype Canterbury Museum, paratypes Otago Museum, Dominion Museum.)
Records. Canterbury: Lake Rubicon, ex moss, November 19, 1950, R. R. Forster; Westland, Waitangituna River, ex leafmould, December 5, 1949, R. R. Forster.
Text-fig. 5.—Fig. 23—Textricella insula n.sp. Retrolateral view of male palp. Figs. 24–25—Textricella signata n.sp. Fig. 24—Retrolateral view of male palp. Fig. 25—Female internal genitalia. Figs. 26–27—Textricella propinqua n.sp. Fig. 26—Retrolateral view of male palp. Fig. 27—Female internal genitalia.
Textricella propinqua n.sp. Figs. 26–27.
Male. Measurements: Carapace—Length, 0.52; width, 0.42; height, 0.25. Abdomen—Length, 0.79; width, 0.52.
Colour. Cephalothorax and abdominal scutes golden brown, legs pale yellow brown.
Eyes. Six. Ratio ALE:PME:PLE = 3:2:3. The PME are small and are separated from each other by a distance equal to twice their diameter and by slightly more than this distance from the PLE. The ALE are separated from each other by a distance equal to five times the diameter of a PME.
Chelicerae. With protuberance on prolateral surface. Promargin with 3 pegs, 2 basal and 1 distal, retromargin with 3 teeth, one basal, two distal.
Palp (Fig. 26). Dorsal surface of the patella beyond knobbed process excavated. Conductor very stout and denticulate.
Abdomen. The abdominal hairs each rise from a small sclerotic plate as in most species of Textricella, but they are somewhat larger and more conspicuous in propinqua and the lateral surfaces between the scutes tend to be furrowed. Both dorsal and ventral scutes are present. Spinnerets encircled by sclerotic ring.
Female. Measurements: Carapace—Length, 0.52; width 0.42; height, 0.23. Abdomen—Length, 0.73; width, 0.50.
Abdomen pale golden yellow, setal plates distinct. Internal genitalia as in Fig. 27. Chelicerae with one tooth on promargin, 4 on retromargin.
Types. Holotype male, allotype female, paratypes. Cass River ex moss, May 23, 1954, J. S. Dugdale; Paratypes, Cass, ex moss, December 25, 1950, B. Wisely. (Holotype, allotype, Canterbury Museum, paratypes Otago Museum, Dominion Museum.)
Records. Canterbury: Craigieburn Stream, February 5, 1950, A. G. McFarlane; Okuku Pass, ex moss, May 21, 1956, R. R. Forster; Lewis Pass, Kiwi Valley, ex leafmould, November 14, 1949, R. R. Forster; Broken River, ex leafmould, February 5 1950, A. G. McFarlane. Westland: Lake Poringa, ex leafmould, January 26, 1954, J. T. Salmon; boundary Murchison and Buller Counties, December 3, 1949, J. H. Sorensen; Moana, ex leafmould, March 10, 1950, R. R. Forster; same locality, September 3, 1951, B. Wisely; Seddonville, ex leafmould, April 19, 1948, A. W. B. Powell; Bruce Bay, ex leafmould, from boggy White Pine forest, January 27, 1954, J. T. Salmon. Nelson: Salisbury Hut, Mt. Arthur Tableland, ex moss, February 21, 1946, J. T. Salmon. Fiordland: Key Summit, ex leafmould, January 26, 1946, R. R. Forster.
Remarks. This species appears to be most closely related to salmoni from the North Island, with which it agrees in having only six eyes, but the stout conductor of the male palp and the structure of the female internal genitalia clearly separates it from this species.
Textricella vulgaris n.sp. Figs. 28–32.
Male. Measurements: Carapace—Length, 0.44; width, 0.37; height, 0.26. Abdomen—Length, 0.62; width, 0.39.
Colour. Carapace and sternum and scutes orange-brown. Appendages paler brown.
Eyes (Fig. 30). Eight. When viewed from above the posterior row appears straight and the anterior row slightly procurved, from in front both rows appear somewhat recurved. Ratio of AME:ALE:PME:PLE = 3:11:10:12. The AME are separated from each other by a distance equal to their width and from the ALE by 2½ times this distance. The PME are separated from each other by a distance equal to three times the width of an AME and from the PLE by slightly more than this distance. Clypeus vertical, equal in height to six times the diameter of an AME.
Chelicerae (Fig. 31). Without boss. With three pegs on promargin and three teeth on retromargin.
Legs. 184.108.40.206. Spines lacking.
Palp (Fig. 28). Patella with a strong, bluntly round lobe on the disto-dorsal surface. Conductor stout.
Abdomen. Both dorsal and ventral scutes present. Spinnerets encircled by sclerotic ring.
Female. Measurements: Carapace—Length, 0.42; width, 0.35; height, 0.25. Abdomen—Length, 0.68; width, 0.41.
Abdomen without dorsal scute: ranging in colour from creamy white to dark grey. Internal genitalia as in Fig. 29. Chelicerae with four teeth on promargin and one on retromargin as shown in Fig. 32.
Types. Holotype male, allotype female, paratypes, Fiordland: Lake Te Au near South Arm of Lake Te Anau, ex moss, Jan. 12–24, 1953, R. R. Forster. (Holotype, allotype, paratypes, Canterbury Museum; paratypes, Otago Museum, Dominion Museum.)
Records. Fiordland: Lake Gunn, ex leafmould, December 29, 1944, J. T. Salmon; Lake Manapouri, ex leafmould, February 6, 1946, R. R. Forster; Beehive, South side of Lake Manapouri, ex leafmould, February 6, 1946, R. R. Forster; Peninsula, south side of Lake Manapouri, ex moss and lichens, February 6, 1946, R. R. Forster; Cleddau Valley, ex leafmould, December 20, 1943, J. T. Salmon; Lake Hankerson, February 14, 1953, J. Ramsay; Cascade Creek, Eglinton Valley, ex moss, February 10, 1955, R. R. Forster, same locality, January 23, 1951, R. R. Forster; April 10, 1956, H. Walker; Caswell Sound, ex moss, April 2, 1949, R. R. Forster; Stillwater Base Camp, Caswell Sound, ex leafmould, April 11, 1949, R. R. Forster; Martins Bay, ex leafmould, January 28, 1955, R. R. Forster. Westland: Moana, ex leafmould, September, 1951, B. Wisely; Taipo River, ex leafmould, January 3, 1951, R. Jacobs; Lake Ianthe, ex leafmould, January 27, 1954, J. T. Salmon; Franz Josef, ex moss, August 2, 1953, M. Warren; same locality, April 26, 1951, R. R. Forster; Fergusons Bush, near Hokitika, ex leafmould, December 9, 1949, R. R. Forster; Okarito, ex moss, December 7, 1949, R. R. Forster; Bruce Bay, ex leafmould, January 10, 1956, W. Clark. Nelson: Flora Saddle, 3,200ft, ex moss, January 20, 1948, R. R. Forster; Flora Track, 3,000ft, ex leafmould, January 29, 1948, R. R. Forster; Leslie Valley Track, ex leafmould, January 23, 1948, R. R. Forster; Lake Hanlan, Karamea Bluff, ex leafmould, January 29, 1954, J. T. Salmon; Salisbury Opening, Mt. Arthur Tableland, ex moss, January 23, 1948, J. T. Salmon. Canterbury:· Lewis Pass, Kiwi Valley, ex moss, November 14, 1949, R. R. Forster; Arthur's Pass, 2,500ft, ex leafmould, January 14, 1951, E. W. Dawson; same locality, ex moss, December 9, 1949, R. R. Forster; McGrath's Creek, Arthur's Pass, ex leafmould, January 3, 1950, E. W. Dawson; Anticrow River, ex moss, October 15, 1952, J. S. Dugdale; Upper Doubtful River, ex leafmould, April 6, 1953, W. F. Dukes; Lake Sumner, ex moss, April 13, 1952, J. S. Dugdale; Lake Rubicon, ex moss, November 19, 1950, R. R. Forster; Lake Janet, August 28, 1951, J. S. Dugdale; Mount Cook, Governor's Bush, ex leafmould, December 1, 1948, J. T. Salmon.
Remarks. This distinctive species appears to be limited mainly to the West side of the Southern Alps, but has extended its range to the east through Arthurs Pass to Canterbury.
Textricella antipoda n.sp. Figs. 33–34.
Male. Measurements: Carapace—Length, 0.46; width, 0.39; height, 0.29. Abdomen—Length, 0.56; width, 0.44.
Colour. Cephalothorax and abdominal scutes deep golden brown. Appendages pale brown.
Eyes. Eight. Ratio of AME:ALE:PME:PLE = 5:15:11:15. AME separated from each other and from the ALE by a distance equal to the diameter of an AME. PME separated from each other and the ALE by twice this distance. Median ocular quadrangle twice as wide behind as in front, while the ratio of the width behind to the length is 6:5. Clypeus vertical, height equal to eight times the diameter of an AME.
Text-fig. 7.—Figs. 33–34. Textricella antipoda n.sp. Fig. 33—Retrolateral view of male palp. Fig. 34—Internal genitalia of female. Figs. 35–36—Textricella mcfarlanei n.sp. Fig. 35—Retrolateral view of male palp. Fig. 36—Internal genitalia of female. Fig. 37—Textricella plebeia n.sp. Internal genitalia of female.
Chelicerae with a small secondary tubercle on the proximal surface.
Palp (Fig. 33). Patella with a platelike process beyond the usual knobbed process. Conductor stout and ridged transversely.
Legs 220.127.116.11 with no spines.
Abdomen. With well developed dorsal and ventral scutes. Spinnerets encircled by a selerotic ring.
Female. Measurements: Carapace—Length, 0.46; width, 0.39; height —. Abdomen—Length, 0.69; width, 0.54.
Abdomen pale grey, setae based in small sclerites. Dorsal scute absent, spinnerets enclosed in sclerotic ring Internal genitalia as in Fig. 34.
Types. Holotype male, allotype female, paratypes. Meads Landing, Lake Hawea (Canterbury Museum).
Remarks. The structure of the male palp and internal genitalia of the female indicates a close relationship between this species and mcfarlanei.
Textricella mcfarlanei n.sp. Figs. 35–36.
Male. Measurements: Carapace—Length, 0.46; width, 0.42; height, 0.27. Abdomen—Length, 0.63; width, 0.44.
Colour. Cephalothorax and abdominal scutes deep golden brown, legs pale yellow-brown.
Eyes. Eight. Ratio of AME:ALE:PME:PLE = 7:20:10:20. AME separated from each other by distance equal to half diameter of AME and from ALE by distance equal to the diameter of an AME. PME are separated from each other and from the PLE by a distance equal to 1½ times the width of an AME. Median ocular quadrangle wider behind than in front in ratio of 30:18 and wider behind than long in ratio of 30:23. Clypeus vertical, height equal to 7 times diameter of an AME.
Chelicerae without tubercle Promargin with three pegs, retromargin with 2 teeth.
Palp. As shown in Fig. 35.
Abdomen. Dorsal and ventral scutes present. Ventral scute extending back to epigastric furrow. Spinnerets encircled by sclerotic ring.
Female. Measurements:· Carapace—Length, 0.46; width, 0.35; height, 0.25. Abdomen—Length, 0.67; width, 0.52.
Abdomen grey. Dorsal scute absent. Chelicerae with three teeth on retromargin, one on promargin. Internal genitalia as in Fig. 36.
Types. Holotype male, allotype female, paratypes. Southland: Temple River, Lake Ohau, ex leafmould. January, 1950, A. G. McFarlane. (Holotype, allotype, Canterbury Museum, paratype, Otago Museum.)
Textricella plebeia n.sp. Fig. 37.
Female. Measurements: Carapace—Length, 0.56; width, 0.39; height, 0.35. Abdomen—Length, 0.58; width, 0.50.
Colour. Cephalothorax yellow brown, appendages dull yellow.
Abdomen creamy white.
Eyes. Six. Ratio ALE:PME:PLE = 5:3:5. The PME are separated from each other by a distance equal to their width and from the PLE by 2½ times this width. ALE separated from each other by distance equal to 2 ½ times their width Clypeus vertical, height equal to the distance between the ALE.
Chelicerae without protuberance. Promargin with four teeth, retromargin with single tooth.
Abdomen. Setal sclerites small. Internal genitalia as shown in Fig. 37. Spinnerets encircled by a faint sclerotic ring.
Types. Holotype female and paratype female. Codfish Island, Sealers Bay, November 4, 1948, R. K. Dell. (Holotype Dominion Museum, paratype Otago Museum.)
Remarks. This species is related to both propinqua and salmoni, but the female internal genitalia are clearly distinct from either of these two species.
Textricella salmoni n.sp. Figs. 38–45.
Male. Measurements: Carapace—Length, 0.50:width, 0.39; height, 0.33. Abdomen—Length, 0.60; width, 0.48.
Colour. Cephalothorax and abdominal scutes reddish-brown. Appendages pale yellow-brown.
Eyes. Six. Ratio of ALE:PME:PLE 2:1:2. The ALE are separated from each other by a distance equal to twice the diameter of an ALE. PME separated from the PLE by a distance equal to the width of an ALE and from each other by half this distance. Height of clypeus equal to twice the diameter of an ALE.
Chelicera without lobes, promargin with three pegs, retromargin with four teeth.
Palp. As in Fig. 43. Patella without distal process, excavated below knobbed process. Legs. 18.104.22.168, without spines.
Abdomen. Dorsal and ventral scutes present. Six spinnerets with colulus enclosed by sclerotic ring. (Fig. 45.)
Female. Measurements: Carapace—Length, 0.41; width, 0.39; height, 0.29. Abdomen—Length, 0.73; width, 0.63.
Text-fig.. 8.—Figs. 38–45—Textricella salmoni n.sp. Fig. 38—Dorsal surface of body of male. Fig. 39—Ventral surface of body of male. Fig. 40—Dorsal surface of body of female. Fig. 41—Ventral surface of body of female. Fig. 42—Internal genitalia of female. Fig. 43—Retrolateral view of male palp. Fig. 44—Female pedipalp. Fig. 45—Colulus and spinnerets of female.
Abdomen pale yellow. Chelicerae with one tooth on promargin, 4 on retromargin. Internal genitalia as in Fig. 42.
Types. Holotype male, allotype female, paratypes. Desert Road, ex leafmould, April 28, 1956, J. T. Salmon; paratype same locality, March 24, 1948, R. R. Forster. (Holotype, allotype Dominion Museum, paratypes Otago Museum, Canterbury Museum.)
Records. Waiouru, Morere Stream, November, 1953, R. K. Dell; Waikaremoana, Maruiana Arm, ex leafmould, December 11, 1946, R. R. Forster; Ngamoko Track, 2,300ft, ex leafmould and moss, May 9, 1956, R. R. Forster; Mt. Gnamoko,
3,000ft, ex leafmould, December 13, 1946, R. R. Forster; Mamaku Bush, near Rotorua, March 23, 1946, J. T. Salmon; Rotoehu near Rotorua, January 10, 1952, R. J. Thornton; Te Marua, ex leafmould, April 12, 1947, G. Ramsay; Horopito, ex leafmould, December 22, 1948, R. R. Forster. Wellington: Tararua Range, below Field's Hut, ex moss and lichen, February 1, 1952, B. A. Holloway; Akatarawa Divide, 1,500ft, ex leafmould, January 3, 1947, J. T. Salmon. Wairarapa: Mount Ross, ex leafmould, April 5, 1947, R. R. Forster; Turanganui River, ex leafmould, June 14, 1947, R. K. Dell.
Remarks. This species is named for Dr. J. T. Salmon who first developed in New Zealand the systematic use of the Berlese Funnel techniques by which large series of microspiders have been secured.
Textricella scuta n.sp. Figs. 46–50.
Male. Measurements:· Carapace—Length, 0.56; width, 0.44; height, 0.39. Abdomen—Length, 0.61; width, 0.50.
Colour. Cephalothorax and abdominal scutes deep yellow-brown. Legs pale yellow-brown.
Eyes. Six. Ratio of ALE:PME:PLE = 4:3:4. ALE separated by distance equal to twice their diameter. PME separated from each other by distance equal to half diameter of an ALE and from the PLE by distance equal to the diameter of a PME. Clypeus vertical, height equal to 2½ times the diameter of an AME.
Chelicerae without secondary tubercle. Promargin with 1 peg, retromargin with 3 teeth.
Legs. Typical, without a secondary spine.
Palp (Figs. 47, 48). Patella with a sharp, slender disto-dorsal projection in addition to the knobbed process. This projection is relatively longer and more slender in the specimens from Fiordland. The conductor is short and stout, with the dorsal surface serrate.
Abdomen. The most striking character distinguishing this species is the extension of the ventral scute back to approximately ⅔ of the distance between the epigastric groove and the spinnerets (Fig. 46). The spinnerets are encircled by a sclerotic ring.
Female. Measurements: Carapace—Length, 0.56; width, 0.37; height, 0.33. Abdomen—Length, 0.75; width, 0.61.
Abdomen creamy white, shaded with grey, internal genitalia as in Fig. 49. Mammillary ring not well defined. Chelicera with four teeth on promargin, one on retromargin. (Fig. 50.)
Types. Holotype male, allotype female, paratypes, Hawkes Bay, Norsewood, ex leafmould, January 27, 1948, P. J. Culleford. (Holotype, allotype, Dominion Museum, paratypes, Canterbury Museum, Otago Museum.)
Records. North Island—Taranaki: Dawson Falls, Mt. Egmont, ex leafmould, sub-alpine belt, 3,600ft, May, 1954, M. P. Beechter. Wellington: Stokes Valley, ex moss, August 10, 1952, B. A. Holloway; Wainui-o-mata Waterworks, Skull Gully Ridge, ex leafmould, B. A. Holloway; South Island—Canterbury: Cass, ex moss, December 23, 1950, R. R. Forster; Carrington Hut, Junction of White and Waimakariri rivers, ex moss, October 11, 1952, J. S. Dugdale. Nelson: Lake Hanlon, Karamea Bluff, ex leafmould, January 29, 1954, J. T. Salmon. Westland: Camerons, ex leafmould, September 5, 1950, R. A. Chapman. Fiordland: Cascade Creek, Eglinton Valley, ex moss, February 10, 1955, R. R. Forster; West Te Anau, 3,000ft, ex leafmould, February 1, 1950, R. S. Duff; Milford Sound, ex leafmould, January 20, 1946, R. R. Forster; Manapouri, ex leaf litter, September 17, 1957, B. J. Marples.
Remarks. Textricella scuta is the only known species where the ventral scute of the male extends back beyond the epigastric groove. Both the internal genitalia of the female and the male palp readily distinguish the species from all other known forms.
Textricella pusilla n.sp. Figs. 51–57.
Male. Measurements: Carapace—Length, 0.39; width, 0.31; height, 0.27. Abdomen—Length, 0.46; width, 0.40.
Text-fig.. 10.—Figs. 51–57—Textricella pusilla n.sp. Fig. 51—Side view of male. Fig. 52—Carapace and chelicerae from in front. Fig. 53—Internal genitalia of female. Fig. 54—Prolateral surface of male palp. Fig. 55—Retrolateral surface of male palp. Fig. 56—Teeth of female chelicera. Fig. 57—Teeth of male chelicera.
Colour. Cephalothorax and legs dark reddish-brown. Abdomen black.
Carapace (Fig. 51). Smooth and shiny. Almost as high as wide. When viewed from the side almost square in outline, dorsal surface of the head region flat, thoracic region short, steeply sloping.
Eyes (Fig. 52). Eight. From above both rows appear straight but from in front the anterior row is strongly procurved and the posterior row gently procurved. Ratio of AME:ALE:PME:PLE = 3:8:5:8. The AME are separated from each other and from the ALE by the diameter of an AME. The PME are separated from each other and from the PLE by a distance equal to twice the diameter of an AME. The median ocular quadrangle is wider behind than in front in the ratio of 8:5 and the ratio of width behind to length is 8:6. Clypeus vertical, height equal to five times the diameter of an AME.
Chelicerae (Fig. 57). Retromargin with three sharp teeth, two basal teeth contiguous, promargin with two pegs.
Legs 22.214.171.124. Legs 1–3 with two (1.1) trichobothria on tibiae and one on metatarsi. Leg 4 with three (1.1.1) trichobothria or tibia, none on metatarsus. Tarsal drum proximal.
Palp (Fig. 54). Patella with a broad retrolateral lobe. Tibia with a strong dorsal spinous process. Bulb simple with a short, sharp embolus, conductor absent.
Abdomen. Oval, small ventral scute, dorsal scute lacking.
Female. Measurements: Carapace—Length, 0.38; width, 0.31; height, 0.27. Abdomen—Length, 0.51; width, 0.44.
Similar in general structure to male. Chelicerae with a single tooth on promargin and 4 teeth on retromargin (Fig. 56). Internal genitalia as in Fig. 53.
Types. Holotype male, allotype female, paratypes. Canterbury: Creek east of Dog Hill, tributary of Hurunui River, ex moss, May 12, 1952, J. S Dugdale. (Holotype, allotype, Canterbury Museum, paratypes, Otago Museum, Dominion Museum.)
Records. Canterbury: Mount Grey, ex moss, March 27, 1951, R. R. Forster. Okuku Pass, ex moss, April 6, 1952, J. S. Dugdale; same locality, March 30, 1952, J. S. Dugdale. Wellington: Orongorongo, ex moss on slopes of the Catchpole Stream, October 25, 1954, V. J. Wilson; Little Barrier Island, Summit Track, 2,000–2,300 feet, ex moss, C. Parkin.
Remarks. The structures of the genitalia of both male and female are most distinctive and separate the species sharply from all other known species, but the general structural characters seem to indicate that the species is correctly located in Textricella.
Textricella tropica n.sp. Figs. 58–63.
Male Measurements: Carapace—Length, 0.39; width, 0.41; height, 0.25. Abdomen—Length, 0.42; width, 0.29.
Colour. Cephalothorax and appendages reddish brown. Abdomen bluish black, with a number of small yellow patches.
Carapace. Finely coriaceous not as high as wide.
Eyes (Fig. 58). Eight, relatively large. From above posterior row appears straight, anterior recurved, from in front both rows appear gently procurved. Ratio of AME:ALE:PME:PLE = 2:5:5:5. The AME are separate from each other by ½ and from the ALE by ¾ of the diameter of an AME. PLE separated from each other and from the PLE by a distance equal to the diameter of an AME. Median ocular quadrangle wider behind than in front in the ratio of 12.5 and wider behind than long in the ratio of 12:10. Clypeus vertical, equal in height to three times the diameter of an AME.
Chelicerae (Fig. 63). Retromargin with two teeth, promargin with three “pegs”.
Legs 126.96.36.199. Spines absent. Two (1.1) trichobothria are present on the tibia of legs 1–3, three (1.1.1) on the tibia of leg 4. Metatarsi of legs 1–3 with single trichobothrium.
Palp (Figs. 59, 60). Patella with three processes. Conductor and embolus filiform.
Abdomen. Ventral plate small, dorsal plate lacking. Six spinnerets with prominent colulus, mammillary ring lacking.
Female. Measurements: Carapace—Length, 0.37; width, 0.36; height, 0.23. Abdomen—Length, 0.40; width, 0.34.
Text-fig.. 11.—Figs. 58–63—Textricella tropica n.sp. Fig. 58—Carapace and chelicerae from in front. Fig. 59—Male palp from below. Fig. 60—Male palp from above. Fig. 61—Internal genitalia of female. Fig. 62—Female chelicera. Fig. 63—Male chelicera.
In general appearance as in male. Internal genitalia as shown in Fig. 61. Cheliceral teeth as in Fig. 62.
Types. Holotypes male, allotype female, New Guinea, Daulo Pass, Central Highlands, ex moss, rain forest, 8,000ft, August 22, 1956, T. E. Woodward; paratypes, Comanigu Valley, Ramu-Purari Divide, ca. 3 miles, S.W. of Mount Otto, Central Highlands, 7,500–8,500 feet, ex moss, rain forest, August 18, 1956, T. E. Woodward. (Holotype, allotype, Queensland Museum, paratypes Otago Museum.)
Genus Micropholcomma Crosby and Bishop, 1927
|1927.||Micropholcomma Crosby and Bishop, Journ. N.Y. Entomol. Soc. 35.|
|1932.||Microlinypheus Butler, Proc. Roy. Soc. Victoria 44 (2).|
|1932.||Plectochetos Butler, Proc. Roy. Soc. Victoria 44 (2).|
Crosby and Bishop established Micropholcomma for a species from Victoria. In 1932 Butler established the genera Microlinypheus and Plectochetos for two further species from Victoria. Hickman considered that Microlinypheus bryophila
Butler should be placed in Micropholcomma and a close examination of both males and females of Plectochetos longissimus Butler and the structure of the respiratory system leads me to conclude that this species is also congeneric with M. caeligenus Crosby and Bishop.
Micropholcomma longissima (Butler) 1932.
1932. Plectochetos longissimus Butler. Proc. Roy. Soc. Victoria 44 (2), p. 107. Figs. 64–69.
Male. Measurements: Carapace—Length, 0.38; width, 0.36; height, 0.32. Abdomen—Length, 0.60; width, 0.56.
Colour. Cephalothorax, appendages and soft portions of abdomen pale yellow-brown. Abdominal scutes darker brown.
Carapace (Fig. 64). Seen from the side the carapace is almost square. The dorsal surface of the head region is flattened and slopes very very steeply down to the posterior margin of the carapace. There is no thoracic groove.
Eyes. Eight. From above the posterior row is strongly recurved. Ratio of AME:ALE:PME:PLE = 4:6:6:5. AME separated from each other and ALE by distance equal to half of diameter of an AME. Lateral contiguous; PME separated from each other and from the PLE by a distance equal to the diameter of an AME. Clypeus high, slightly concave, height equal to five times the diameter of an AME.
Chelicerae (Fig. 69). Vertical; without boss. There appears to be a single tooth and a stout peg on the retromargin, promargin smooth. There is a long smooth hair at the side of the tooth and 2 ciliate hairs on the promargin with a distal mound from which extend a long ciliate hair and a shorter smooth hair.
Legs. 188.8.131.52. Clothed with slender, smooth hairs, except on ventral surfaces of metatarsi and tarsi of legs 3 and 4, where the hairs are stronger and serrated. Three trichobothria present only on tibiae arranged 2.1 on legs 1–3 but 1.1.1 on leg 4. No trichobothria on metatarsi. Three claws, superior homogeneous with 3–4 teeth, inferior smooth. Tarsal drum proximal.
Palp (Figs. 67, 68). Tibia with a short projection on the mid-dorsal surface. Tarsus and bulb twisted out so that the morphologically ventral surface is retrolateral. Tarsus flattened with irregular shape as shown in Fig. 68, distal surface indented. Conductor coiled.
Abdomen. Ovoid, not rising above carapace. Well developed scutes present on both dorsal and ventral surfaces. Lateral surfaces with longitudinal ridges. Six spinnerets and colulus in compact group, posteriorly situated, encircled by sclerotic ring.
Female. Abdomen without dorsal scute but surface coriaceous with numerous small sclerotic plates, of which the smaller are setose. The openings of the epigynum are placed in front of the posterior margin of the ventral scute. Internal genitalia simple. A long, straight tube leads back to a simple receptaculum which is situated immediately behind the petiolus (Fig. 66).
Type. Male described by Butler from Mt. Donna Buang, Victoria, in National Museum of Victoria.
Records. Tasmania: Dove River, near Crater Lake, Cradle Mountain, ex moss in Beech forest, February 21, 1955, T. W. Woodward. N.S. Wales: National Park, ex leafmould, August 24, 1952, T. E. Woodward. S. Queensland: Beechmont, August 1, 1954, T. E. Woodward.
Remarks. This species was originally placed by Butler into a separate genus Plectochetos. I consider that the species is congeneric with Micropholcomma bryophila (Butler) described in the same paper.
Micropholcomma bryophila (Butler) 1932.
New Records. Tasmania: Hugel River, Tasmania, Lake St. Clair National Park, ca. 2,700ft, ex moss, beech forest, February 15, 1955, T. E. Woodward. Victoria: Mount Donna Buang, ex leafmould, rain forest, January 18, 1951, T. E. Woodward. N.S. Wales: Barrington Tops, ex moss, December 22, 1957, T. E. Woodward. S. Queensland: Beechmont, ex leafmould, August 1, 1954, T. E. Woodward.
Genus Pua n. gen.
Carapace high, without thoracic groove. Six eyes in two groups of three. Sternum convex, obtuse behind. Chelicerae without condyle, teeth present on both margins. Maxillae convergent. Legs 184.108.40.206., without spines. Trichobothria present on tibiae of all legs, absent from metatarsi. Tarsi much longer than metatarsi, tarsal drum proximal. Three claws. Male palp with patellar process. Female palp small without claw, with reduced number of segments. Abdomen in both sexes with dorsal and ventral scute. Six spinnerets and colulus. Posterior spiracles lacking. Anterior spiracles supplying tracheae to both cephalothorax and abdomen.
Type species Pua novazealandiae n.sp.
This genus appears to be closely related to Micropholcomma, from which it is clearly separated by the number and arrangement of the eyes, differences in the distribution of trichobothria and the absence of the posterior spiracle.
Pua novaezealandiae n.sp. (Figs. 70–77.)
Male. Measurements: Carapace—Length, 0.37; width, 0.31; height, 0.29. Abdomen—Length, 0.48; width, 0.48.
Colour. Body and appendages golden yellow.
Carapace (Fig. 70). Smooth. From the side the head region appears gently rounded highest posteriorly where it slopes steeply to the posterior margin. There are four median pairs of setae along the dorsal surface of the head progressively smaller anteriorly. Thoracic groove absent.
Eyes (Fig. 72). Six in two triads. Ratio of ALE:PME:PLE = 4:3:4. From above the posterior row is recurved, while from in front it appears procurved. The lateral eyes are sub-contiguous. PLE separated from AME by distance equal to ½ width of an ALE. ALE and PME both separated from each other by a distance equal to the diameter of an AME.
Chelicerae (Fig. 73). Vertical without boss. Furrow with short basal tooth and a small tooth and longer peg on promargin. Four ciliate hairs above promargin.
Maxillae somewhat triangular, transverse. Labium fused, twice as wide as long. Sternum convex smooth, almost as wide as long, terminated broadly behind, separating coxae 4 by twice their width.
Legs. 220.127.116.11. Clothed with smooth hairs, spines lacking. Tarsal drum proximal. Three claws, apparently smooth. Tibiae of legs 1–3 with two trichobothria, one at ⅓, the other at ½ of the length of the segment. Tibia 4 with row of three. Trichobothria absent from all metatarsi.
Palp (Figs. 76, 77). There is a blunt, curved process on the distal retrolateral surface of the patella. Bulb simple with a short curved embolus on the sub-distal retrolateral surface.
Abdomen (Fig. 70). Oval, with well developed scutes on both dorsal and ventral surfaces. Six spinnerets and colulus surrounded by sclerotic ring.
Female. Measurements: Carapace—Length, 0.34; width, 0.29; height, 0.22. Abdomen—Length, 0.56; width, 0.48.
|Leg 1||0. 26||0. 08||0. 21||0. 11||0. 21||0. 87|
|Leg 2||0. 23||0. 07||0. 18||0. 10||0. 21||0. 79|
|Leg 3||0. 21||0. 05||0. 18||0. 08||0. 21||0. 73|
|Leg 4||0. 31||0. 08||0. 21||0. 11||0. 22||0. 93|
|Palp Three segments||0. 05||0. 02||0. 08||0. 15|
Text-fig. 13.—Figs. 70–77—Pua novaezealandiae n. gen., n. sp. Fig. 70—Side view of male. Fig. 71—Ventral view of female. Fig. 72—Carapace and chelicerae of male showing eyes. Fig. 73—Chelicera of male Fig. 74—Chelicera of female. Fig. 75—Female pedipalp. Fig. 76—Prolateral surface of male palp. Fig. 77—Retrolateral view of male palp.
Similar in general character to the male. Both dorsal and ventral scutes are present. Internal genitalia simple, in form of single large sacs, which are visible as patches through the ventral scute (Fig. 71). The pedipalps are small, with the tibia and tarsus fused into a single segment (Fig. 75). There is a minute, blunt, distal process present which has the appearance of a vestigial claw.
Types. Holotype male, allotype female and paratypes—Canterbury· Lewis Pass, 2,200ft, ex leafmould, January 29, 1956, R. R. Forster (holotype, allotype, Canterbury Museum, paratypes, Otago Museum, Dominion Museum).
Records. North Island: Lake Waikaremoana, ex leafmould, December 19, 1946, R. R. Forster; Waikaremoana, Panikiri Bluff, 3,800ft, December 12, 1946, R. R. Forster; Horopito, ex leafmould, December 22, 1948, R. R. Forster; Wellington, Pinehaven, February 22, 1953, R. K. Dell; Day's Bay, November 30, 1947, R. R. Forster; Tararua Range, below Field Hut, ex moss and lichens, December 8, 1952, B. A. Holloway South Island. Canterbury, Kiwi Valley, Lewis Pass, ex leafmould, November 14, 1949, R. R. Forster; Lake Rubicon, ex moss, November 19, 1950, R. R. Forster Westland: Camerons, September 5, 1950, R. A. Chapman.
Genus Parapua n.gen.
Carapace high, without thoracic groove. Eight eyes in two rows. Posterior row recurved. Sternum convex, broadly rounded behind. Chelicerae without condyles, teeth on retromargin only. Legs 1: 4: 2: 3 without spines, trichobothria on all tibiae and metatarsi of legs 1–3, absent from metatarsus 4. Tarsi much longer than metatarsi, tarsal drum proximal, three claws. Male palp with patellar process. Female palp without claw, small; with reduced number of segments. Abdomen with ventral scute, dorsal scute lacking. Six spinnerets and colulus. Posterior spiracle absent, tracheae from anterior spiracles supplying both cephalothorax and abdomen.
Type species Parapua punctata n. sp.
Parapua shares many characters with Micropholcomma, but may be separated from it by the absence of a posterior spiracle and the different form of the male palp.
Parapua punctata n. sp. (Figs. 78–81).
Male. Measurements: Carapace—Length, 0. 51; width, 0. 50, height, 0. 31. Abdomen—Length, 0. 67, width, 0. 67.
|Leg 1||0. 58||0. 15||0. 48||0. 25||0. 32||1. 78|
|Leg 2||0. 50||0. 15||0. 41||0. 21||0. 30||1. 57|
|Leg 3||0. 42||0. 12||0. 37||0. 21||0. 30||1. 42|
|Leg 4||0. 49||0. 13||0. 43||0. 22||0. 31||1. 58|
|Palp||0. 06||0. 06||0.19||0. 31|
Colour. Cephalothorax and abdominal scutes deep reddish-brown. Appendages paler yellow-brown. Soft portions of abdomen blackish grey.
Carapace (Fig. 78). Coarsely punctate. The anterior portion of the eye region slightly overhangs the clypeus. The head region is flat when viewed from the side and the slopes, and then slopes gently down posteriorly to the petiolus. Thoracic groove lacking.
Eyes Eight. When viewed from above both rows are strongly recurved, when viewed from in front the posterior row appears procurved while the anterior row is recurved. Ratio of AME: ALE: PME:·PLE = 6: 6:7:6. AME are separated from each other by ⅓ and from the ALE by ½ of width of an AME. Lateral eyes contiguous. PME separated from each other by ½ and separated from the PLE by a distance equal to the diameter of an AME. Clypeus curving under the AME, height equal to three times the diameter of an AME. Clypheus curving under the AME, height equal to three times the diameter of an AME.
Chelicerae (Fig. 79). Vertical, without lobes. There is a single tooth on mid-retromargin and further proximal tooth, but the promargin is smooth.
Sternum. Convex, coarsely granulate, slightly longer than wide, almost round in outline, joined to carapace by strips between the coxae. Coxae 4 separated by a distance equal to one
Text-fig. 14—Figs. 78–81.—Parapua punctata n. gen., n. sp. Fig. 78—Side view of body of male Fig. 79—Male chelicera. Fig. 80—Retrolateral surface of male palp Fig. 81.—Female palp.
and a-half times their diameter. Maxillae, twice as long as wide, oblique. Labium fused to sternum, twice as wide as long.
Palp (Fig. 80). Patella with a blunt lobe on the subdistal dorsal surface curved over to the retrolateral surface, followed by a sharp erect process. Bulb simple with a slender spinous embolus on the retrolateral surface. Conductor absent.
Legs. Spines absent. Clothed with smooth hairs. Tibiae of legs 1–3 with three (1. 1. 1) trichobothria, metatarsi with a single median trichobothrium. Tibia of leg 4 with four (1. 2. 1) trichobothria, metatarsus none. Taisal drum proximal. Three claws, prolateral with a ventral row of from 15–20 strong teeth, retrolateral and inferior smooth.
Abdomen. Subglobose, sparsely clothed with long and short smooth hans, spinnerets ventral Dorsal scute absent, with a number of round sclerotic patches on both dorsal and lateral surfaces. Ventral scute encircling the petiolus Six spinnerets and colulus enclosed by a broad sclerotic ring.
Female. Measurements: Carapace—Length, 0.55; width, 0.54; height, 0.40. Abdomen—Length, 0. 71; width, 0. 64.
|Leg 1||0. 54||0. 13||0. 42||0. 28||0. 34||1. 71|
|Leg 2||0. 48||0. 12||0. 42||0. 23||0. 32||1. 57|
|Leg 3||0. 40||0. 10||0. 38||0. 18||0. 31||1. 37|
|Leg 4||0. 50||0. 12||0. 38||0. 21||0. 32||1. 53|
|Palp||0. 03||0. 06||0. 02||0. 11|
In general characters the female agrees with the male. The palp is reduced three segments (Fig. 81) and is very small.
Types. Holotype male. Canterbury: Methven, ex leafmould, June 10, 1954, J. S. Dugdale; allotype female, Canterbury, Hoods Bush, Malvein Hills, ex moss, May 3, 1953, R. R. Forster (Holotype and allotype Canterbury Museum, paratype Otago Museum.)
Records. Canterbury: Lewis Pass, 2,000ft, ex moss, January 29, R. R. Forster; Okuku Pass, ex moss, April 6, 1952, J. S. Dugdale; Pukaratai, ex leafmould, June 19, 1946, A. J. Healy. Fiordland: Cascade Creek, ex moss, January 23, 1951, R. R. Forster; Manapouri, ex moss, January 23, 1951, R. R. Forster; Otago, Meads Landing, Lake Hawea, January 21, 1951, R. R. Forster.
Genus Mysmena Simon 1894
Levi (1956) has given an excellent extended diagnosis of this genus in his revision of the American species. The only character which may be found constant for this genus which was not mentioned by Levi is the presence of numerous small denticles on the surface of the cheliceral furrow between the pro- and retromarginal teeth, which are present in all of the species which have been examined from the Pacific area.
Text-fig. 27.—Figs. 159–166. Mysmena vitiensis n. sp. Fig. 159—Prolateral surface of male palp. Fig. 160—Retrolateral surface of male palp. Fig. 161—Tarsus and bulb of male palp expanded. Fig. 162—Female palp and maxilla Fig. 163—Chelicera of female. Fig. 164—Anterior spinnerets and colulus Fig. 165—Female internal genitalia Fig. 166—Body of male from side.
Mysmena vitiensis n. sp. (Figs. 159–166).
Male. Measurements: Carapace—Length, 0.25; width, 0.21, height, 0.19. Abdomen—Length, 0.39; width, 0.38.
|Leg 1||0. 24||0. 09||0. 22||0. 14||0. 17||0. 86|
|Leg 2||0. 21||0. 08||0. 21||0. 13||0. 16||0. 79|
|Leg 3||0. 16||0. 07||0. 13||0. 18||0. 13||0. 67|
|Leg 4||0. 18||0. 10||0. 14||0. 14||0. 13||0. 69|
|Palp||0. 11||0. 03||0. 04||0. 10||0. 28|
Colour. Entire animal uniform creamy-white.
Carapace (Fig. 166). Smooth, thoracic groove lacking. Rising, evenly, from the posterior margin to the eye region where it is highest. The eye region is produced forward so that it overhangs the clypeus.
Eyes. Eight, large, occupying most of the width of the head when viewed from above. AME dark, others pale. From above the posterior row appears slightly procurved, but from in front appears gently recurved. Ratio of AME: ALE: PME: PLE = 4. 6. 4. 5. The lateral eyes and PME are grouped as two contiguous triads. AME subcontiguous separated from each other by a distance equal to ¼ the width of an AME and from the ALE by ½ of the width of an AME.
Chelicerae Vertical, with three strong teeth on promargin and two on retromargin. The area between the teeth with numerous small denticles.
Sternum. Convex, smooth, as wide as long, truncated posteriorly between coxae 4. Maxillae transverse, not meeting, Labium somewhat wider than long.
Palp (Figs. 159–161). Without processes. Tibia with a single trichobothrium. Cymbium provided with a distal curved projection. Bulb simple with a singly coiled spinous embolus (Figs. 160, 161).
Legs. 1. 2. 4. 3. Clothed with smooth hairs, legs 1–3 with three (2. 1) trichobothria on tibia and one on metatarsus Leg 4 with four (1. 2. 1) trichobothria on tibia, none on metatarsus. Three claws. Tarsal drum proximal. Femoral organ absent.
Abdomen. Ovoid, clothed with smooth hairs, rising above the carapace. Six spinnerets and prominent rod-like colulus (Fig. 164) placed ventrally.
Female. Measurements: Carapace—Length, 0. 37; width, 0. 32; height, 0. 22. Abdomen—Length, 0. 75; width, 0. 58.
|Leg 1||0. 27||0. 11||0. 18||0. 12||0. 15||0. 83|
|Leg 2||0. 26||0. 10||0. 19||0. 14||0. 12||0. 81|
|Leg 3||0. 23||0. 10||0. 15||0. 15||0. 13||0. 76|
|Leg 4||0. 24||0. 11||0. 17||0. 15||0. 13||0. 80|
|Palp||0. 05||0. 02||0. 03||0. 05||0. 15|
Similar to male in general characteristics. Palp lacking claw, with trichobothrium on tibia (Fig. 162). External epigynum without scape. Internal genitalia as in Fig. 165.
Types. Holotype male, allotype female, paratypes, Fiji, Sawani, near Suva, found suspended from the end of fine silken threads on epiphytes, July 19, 1956, R. R. Forster. (Holotype, allotype, Otago Museum, paratypes, Canterbury Museum.)
Mysmena woodwardi n. sp. Figs. 167–171.
Female. Measurements: Carapace—Length, 0. 46; width, 0. 43; height, 0. 25. Abdomen— Length, 0.89; width, 0. 84.
|Leg 1||0. 27||0. 08||0. 14||0. 13||0. 13||0. 75|
|Leg 2||0. 26||0. 09||0. 12||0. 14||0. 13||0. 74|
|Leg 3||0. 16||0. 08||0. 09||0. 12||0. 13||0. 58|
|Leg 4||0. 27||0. 11||0. 16||0. 15||0. 15||0. 84|
|Palp||0. 08||0. 04||0. 07||0. 12||0. 31|
Colour. Carapace reddish-brown with dark shading down the median surface. Abdomen reddish brown with small pale spots along the lateral and anterodorsal surfaces. Legs reddish brown.
Carapace (Fig. 171). Widest behind, narrowing anteriorly. Thoracic groove lacking. Highest in eye region, sloping steeply back to the posterior margin.
[The section below cannot be correctly rendered as it contains complex formatting. See the image of the page for a more accurate rendering.]
Eyes (Fig. 167). Eight, large, occupying most of the width of the head. Ratio AME: ALE: PME: PLE = 7:5:6:5. ALE separated from each other and ALE by 3/7 of the diameter of an AME. Lateral eyes contiguous. PME separated from each other by 9/7 of from the PLE by 2/7 of the diameter of an AME. From in front the anterior row appears straight and the posterior row strongly recurved. From above the posterior row is slightly procurved, while the anterior row is recurved. Clypeus vertical slightly higher than the width of an AME.
Chelicerae (Fig. 170). Promargin with three strong teeth, of which the distal is bifid Retromargin with single tooth, proximal surface of groove armed with numerous denticles.
Sternum. Convex, smooth, almost as wide as long, truncated posteriorly. Maxillae oblique, labium slightly wider than long.
Palp. Claw lacking .Single trichobothrium present on tibia.
Legs. Ventral surface of metatarsus and tarsus of leg 4 with a ventral row of strongly serrate bristles, otherwise legs clothed with smooth hairs. Legs 1–3 with three trichobothria on the tibia and one on the metatarsus. Leg 4 without a metatarsal trichobothrium but with four (1. 2. 1) on tibia. Tarsal drum proximal. Three claws.
Abdomen. Ovoid, rising twice the height of the carapace, clothed with short hairs. Six spinnerets with large triangular colulus furnished with two bristles. Epigynum in form of a broad sclerotic plate, without scape. Internal genitalia as in Fig. 169.
Types. Holotype female, paratype female, New Guinea, Al Valley, Nomdugl, West Highlands, ex moss, rain forest, ca. 6,500ft, T. E. Woodward. (Holotype Queensland Museum, paratype Otago Museum.)
Mysmena samoensis (Marples) 1955.
1955 Linyphia samoensis Marples. Proc. Linn. Soc. London, Vol. XLII, No. 287, p. 494, Pl. 59, Figs. 10, 14, 15, 16.
This species, described from Upolu and Manona, Western Samoa, appears to be a typical Mysmena. The original description for the species clearly characterises it, but I am able to add a few further details.
The epigynum is provided with a long and slender scape. A femoral spot is present on the femur of the first and second legs of the female. There are a number of minute teeth on the distal surface of the cheliceral furrow near the base of the fang. The anterior spiracles lead into short atria which are connected by a transverse duct. From each atrium there are three bunches of tracheae which are limited to the abdomen. There are two large posterior spiracles situated midway between the spinnerets and the epigastric groove, which open into atria. The atria are connected transversely, and a bunch of tracheae passes from each atrium through the petiolus to the cephalothorax.
Mysmena phyllicola (Marples)
1955. Theridion phyllicolum Marples. Proc. Linn. Soc.London, Vol. XLII, No. 287; 488, Pl. 57, Figs. 13, 16, 22; Pl. 58, Fig. 1.
This species appears to belong to Mysmena. It is interesting to note that the anterior spiracles lead into lungbooks which, however, are not typical and resemble those recorded by Levi (1956) for Mysmena guttata. There is a single posterior spiracle from which the tracheae are limited to the abdomen.
Genus Risdonius Hickman, 1938
Risdonius conicus (Forster) 1951.
1951. Chasmocephalon conicum Forster. Rec. Cant. Mus. 5 (4), p. 237, Fig. 134.
Through the courtesy of Dr. V. V. Hickman, I have been able to examine specimens of Risdonius parvus from Tasmania which confirms the present generic placing of conicus. Hickman (1938) placed Risdonius in the Argiopidae because of the presence of the anterior pair of booklungs. A close examination of the respiratory system of both the Tasmanian and New Zealand species convinces me that this genus shows a transitory stage where the anterior respiratory system of parvus and conicus can be regarded either as attenuated booklungs or rudimentary tracheae. I have therefore placed this genus into the Symphytognathidae with which it conforms in most other characters.
The female internal genitalia of R. conicus is simple, consisting of a bilobed receptaculum as in parvus.
Genus Chasmocephalon Cambridge, 1889
The type species for this genus is Chasmocephalon neglectum Cambridge, known from a single specimen collected at the Swan River, Western Australia. Cambridge records his specimen as a male from which both palps had been lost, but it is possible that it is a typical female. Six years later Simon (1895) described a further species C. bimaculatum from South Africa. Hickman (1944) has described C. minutum from Tasmania and the present author (Forster, 1951) C. armatum from New Zealand.
A close examination of the description and figures for C. neglectum suggests that this species may be congeneric with the Australian species which I have placed in Pseudanapis. If this is so it may be necesary after examination of Cambridge's type to establish a further genus for the Tasmanian and New Zealand species It is probable that C. bimaculatum Simon from South Africa is not related to the Australian and New Zealand species, and after further study this species may be found to be better placed in another genus.
Chasmocephalon armatum Forster, 1951.
1951. Chasmocephalon armatum Forster, Rec. Cant. Mus. 5 (4) p. 232.
1951. Chasmocephalon australis Forster, Rec. Cant. Mus. 5 (4), p. 234. Fig. 142.
Examination of the large series of specimens now available from a wide range of localities indicates that there is only one species in New Zealand. The spiders make a small orb web in moss and among loose leaf debris, and are usually found resting in the centre of the web. The New Zealand species is closely related to the Tasmanian C. minutum Hickman.
Originally recorded from Stokes Valley, Wellington, and Bench Island, Foveaux Strait; further records show it to be very widely distributed throughout New Zealand.
New Records. North Island—Wellington: Gollans Valley, September 1, 1948, R. R. Forster; Silverstream, ex leafmould, May 20, 1950, R. K. Dell; Tararua Range, Judd Ridge, near Waterhole, ex leafmould, January 12, 1954, B. A. Holloway; Hawke's Bay: Wallingford, February 12, 1948, G. Ramsay. Taranaki: Hurley-
ville,Patea, ex leafmould, January 10, 1950, D. H. Hurley; Taihape Reserve, ex leafmould, September 6, 1950, T. A. Moyle; Upper Rangitikei, May 8, 1948, J. Ramsay; Waikaremoana, Panekiri Bluff, 3,600ft, December 11, 1946, R. R. Forster; Stephen Island, May 19, 1950, R. R. Forster, same locality, ex leafmould, from the bases of Nikau Palms, near frog bank, December 1, 1953, B. A. Holloway; ex leafmould from scrub near frog bank, December 1, 1953, B. A. Holloway; Inner Chetwode Island, ex leafmould, September 12, 1948, J. T. Salmon; Motu Ngaratiti Island, ex leafmould, September 12, 1948, J. T. Salmon. South Island—Canterbury: Lake Janet, ex leafmould, August 1, 1949, R. R. Forster; Okuku Pass, ex leafmould, August 7, 1949, F. McGregor; March 30, 1952, J. S. Dugdale; Okuti Valley, December 12, 1950, R. R. Forster; Cooper's Creek, ex moss. October 18, 1953, R. R. Forster; Fox's Creek, April 27, 1952, J. S. Dugdale; Kaituna Valley, ex leafmould, August 14, 1950, R. Jacobs; Kennedy's Bush Christchurch, January 12, 1944, J. T. Salmon, Creek east of Dog Hill, tributary of Hurunui River, ex moss, May 12, 1952, J. S. Dugdale; Mount Algidus, ex leafmould, February 12, 1946, R. R. Forster: Cass, July 10, 1949, R. R. Forster; Lewis Pass, 2,200ft. ex moss, January 29, 1956, R. R. Forster, Arthur's Pass. ex moss, December 9, 1949, R. R. Forster. Westland: Camerons, September 5, 1950, R. A. Chapman. Fiordland: North side of Lake Manapouri ex leafmould. February 6, 1946, R. R. Forster; Lake Poteriteri, ex moss, February 9, 1955, G. Ramsay. Southland: Orepuki. May 9, 1949, R. R. Forster; Longwood Range, ex leafmould, September 1, 1948, J. H. Sorensen; March 14, 1948, G. C. Weston; Crest between Crombie and Wairaurahiri Rivers, ex leafmould, May 28, 1948, G. C. Weston; Bluff, ex leafmould. May 19, 1949, J. H. Sorensen. Stewart Island: Horseshoe Bay. November 21, 1946, R. R. Forster. Codfish Island: ex leafmould, July 16, 1948, C. Lindsay.
Genus Pseudanapis Simon, 1905
Pseudanapis insula (Forster, 1951)
1951. Chasmocephalon insulum Forster, Rec. Cant. Mus. 5 (4), p. 242, Fig. 153.
This species was orginally described from a single male from Little Barrier Island.
The female is similar to the male in general characteristics, but the dorsal scute is lacking; the palp is absent and the first leg is without spines. I consider that the species is more correctly placed in Pseudanapis.
New Records. North Auckland: Waipoua, January. 1952, W. R. McGregor; Coromandel, Te Hope-Moehau Track, ex leafmould, January 17, 1952, T. E. Woodward.
Pseudanapis spinipes (Forster, 1951)
1952. Chasmocephalon spinipes Forster. Rec. Cant. Mus. 5 (4), p. 239. Fig. 151.
Originally recorded from Akatarawa Divide and Stokes Valley, Wellington; the present collections increase the range of this species to include both the North and South Islands.
New Records. North Island—Wellington: Waikane, January, 3, 1948, R. R. Forster; Gollans Valley, September 1, 1948, R. R. Forster; Waikato, Onepuki, November 20, 1954, R. R. Forster; Feilding, ex leafmould, January 16, 1952, R. R. Forster; North end of Manawatu Gorge, ex leafmould, December 15, 1946, R. R. Forster; Waikaremoana, Mt. Ngamoko, 2,500ft, ex leafmould, December 13, 1946, R. R. Forster; Waikaremoana, Ngamoko Track, ex foliage, December 20, 1946, R. R. Forster. South Island—Canterbury: Methven, ex leafmould, June 10, 1954, J. S. Dugdale; Kowai Bush, May 18, 1952, J. S. Dugdale; Dean's Bush, Christ-church. December 19, 1949, J. S. Dugdale; Peel Forest, January 20, 1951, R. R. Forster; Cooper's Creek, ex leafmould, December 3, 1948, R. R. Forster.
Pseudanapis burra n. sp. Figs. 82–87.
Male. Measurements: Carapace—Length, 0.67; width, 0.54; height, 0.50. Abdomen—Length, 1.21; width, 0.62.
|Leg 1||0. 84||0. 26||0. 74||0. 26||0. 53||2. 63|
|Leg 2||0. 58||0. 26||0. 53||0. 16||0. 47||2. 00|
|Leg 3||0. 37||0. 16||0. 26||0. 16||0. 37||1. 32|
|Leg 4||0. 58||0. 21||0. 42||0. 17||0. 42||1. 80|
Colour. Carapace and scutes deep reddish-brown, abdomen grey. Legs paler brown.
Carapace (Fig. 82). Head region higher, evenly rounded with a few setose postules, but otherwise smooth. Thorax granulate with shallow median depression.
Eyes (Fig. 83). Six, placed in three contiguous pairs. From in front the posterior row appears strongly procurved; from above it appears slightly procurved. Ratio of ALE: PME: PLE = 10.9. 10. The lateral eyes are situated on a definite lobe. PME separated from the PLE by 14/10 and from the ALE by 12/10 of the diameter of a PME. Clypeus vertical, height equal to three times the diameter of an ALE.
Chelicerae (Fig. 84). Vertical with slight proximo-ventral swellings. Retromargin with three teeth of which the median is bifid, promargin with a median group of three smaller teeth, fused at the base. There is a row of five setose hairs above the promargin.
Sternum. Convex, granulate, almost oval in outline, separating coxae IV by a distance equal to twice their width. Maxillae transverse, twice as long as wide Labium fused to
sternum, twice as wide as long. The sternum is joined with the carapace by strips between the coxae of the legs and a strip passes anteriorly between the chelicerae and maxillae.
Palp (Figs. 85, 86). Patella with a small sharp process on the distal retrolateral surface. Bulb large, simple with two distal processes, one (embolus?) simple and the other (conductor?) distally bifid.
Legs 18.104.22.168. Relatively stout. Femora of legs, 1 and 2 with pustules along the ventral surface. There is a row of short, stout spines along the entire proventral surface of the metatarsus and tarsus and two on the proventral surface of the tibia. Legs 1–3 with three trichobothria.
Female. Measurements: Carapace—Length, 0.71; width, 0.58; height, 0.51. Abdomen— Length, 1.12; width, 0.76.
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Similar to male in general structure. Abdomen lacking a dorsal plate, greyish with irregular cream patches down the dorsal surface.
Types. Holotype male, Queensland, Binna Burra, Lamington Plateau ex leaf-mould, rain forest, August 28, T. E. Woodward; allotype female, same locality, September 7, 1952; paratype female, Ballungui Track, near Binna Burra, ex leaf-mould, October 30, 1955, T. E. Woodward. (Holotype and allotype in Queensland Museum, paratype Otago Museum).
Pseudanapis octocula n. sp. (Figs. 88–91.)
Male. Measurements: Carapace—Length, 0.58; width, 0.46; height, 0.44. Abdomen—Length, 1.21; width, 0.84.
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Colour. Cephalothorax, legs and abdominal scutes reddish brown. Soft portion of abdomen creamy grey.
Carapace (Fig. 88). Head region high and smooth. When viewed from the side, the dorsal surface somewhat flattened but sloping steeply posteriorly to the thoracic groove, which is deep in the middle line but shallow laterally. Thoracic region granulate, with a shallow median depression.
Eyes. Eight. From in front the anterior row is strongly procurved. Ratio of AME: ALE: PME: PLE = 22.214.171.124. The AME are separated from each other and from the PME by a distance equal to ⅔ of the diameter of an AME. The distance between the AME and ALE is equal to 5/2 of the diameter of an AME. The PME are separated from each other by a distance equal to and from the PLE by 7/4 of the diameter of an AME. Laterals contiguous.
Chelicerae (Fig. 90). Relatively long, vertical, slightly bowed when viewed from in front with three small contiguous teeth on mid promargin and three stronger, widely separate teeth on retromargin.
Sternum. Convex, granulate, almost oval in outline, slightly longer than wide. Coxae 4 separated by twice their width. Maxillae transverse twice as long as wide. Labium fused.
Legs 126.96.36.199. Slender, clothed with small hairs, spines lacking. Legs 1–3 with three (2.1) trichobothria on tibia, one on metataisus. Leg 4 with four (1.2.1) trichobothria on tibia and none on metatarsus. Three smooth claws, with false claws on legs 3 and 4. Tarsal drum proximal.
Palp (Fig. 91). Processes lacking. Bulb simple, embolus as broad plate over distal surface, narrowing to a sharp point on the retrolateral surface. Abdomen ovoid, spinnerets ventral, rising well above carapace. Dorsal and ventral plates both well developed. Ventral scute
Text-fig. 16.—Figs. 88–91—Pseudanapis octocula n. sp. Fig. 88—Body of male from side. Fig. 89—Carapace and chelicerae from in front showing the eyes. Fig. 90—Male chelicera. Fig. 91—Retrolateral surface of male palp.
encircles the petiolus extends dorsally. The tracheal spiracles open a short distance from the posterior margin of the ventral scute. There are a series of small sclerotic plates along the lateral surface. Six spinnerets and colulus surrounded by a broad sclerotic band.
Female. Measurements: Carapace—Length, 0.55; width, 0.46; height, 0.44. Abdomen—Length, 1.19; width, 0.84.
Similar in appearance to male, with both dorsal and ventral plates. Palp lacking.
Types. Holotype male, paratype males, Queensland, Binna Burra, ex leafmould, September 7, 1952, T. E. Woodward; allotype female, Sunnybank, Brisbane, October 5, 1955, W. Haseler. (Holotype, allotype, Queensland Museum, paratype, Otago Museum.)
Pseudanapis darlingtoni n. sp. (Figs. 92–97.)
Male. Measurements: Carapace—Length, 0.54; width, 0.54; height, 0.40. Abdomen—Length, 0.75; width, 0.62.
Colour. Carapace, legs and scutes deep reddish brown. Abdomen bluish-grey, with irregular pale dorsal patches.
Carapace (Fig. 93). Head highest in eye region, sloping gently back to thoracic region, subconical when viewed from the side, without well defined thoracic groove.
Eyes. Six, in three pairs, lateral eyes contiguous, placed on a low tubercle median pair subcontiguous. When viewed from above the posterior row is gently recurved, from in front it appears procurved. Ratio of ALE: PME:PLE = 7:6:6. The ALE are separated from each other by five times the diameter of an ALE. PLE separated from PME by distance equal to almost twice the width of an ALE. Clypeus vertical, height equal to three times the diameter of an ALE.
Chelicerae (Fig. 96). Vertical, without bosses. Broad serrate process on promargin, three strong teeth on retromargin and a further strong tooth at a proximal limit of the furrow.
Sternum. Convex, coriaceous, almost oval in outline, slightly longer than wide. Posterior margin rounded and separating coxae IV by a distance equal to twice their width. Maxillae directed across the body, twice as long as wide. Labium fused.
Legs 188.8.131.52. Relatively stout, clothed with smooth hairs. There are bristles on the dorsal surfaces of the patellae and tibiae. Leg 1 with a series of spines along the prolateral and ventral surface of the metatarsus and tarsus and the distal prolateral surface of the tibia. There are smaller spines on the prolateral surfaces of the tibia and metatarsus of leg 2 (Fig. 97). There are three (2–1) trichobothria on the median surface of the tibia of legs 1–3 and a single trichobothrium at ⅔ of the length of the metatarsi. Leg 4 with four (121) trichobothria on tibia, but absent from metatarsus. Three claws, all of which appear to be smooth. Tarsal drum proximal.
Palp (Figs. 94, 95). Patella with a thin expanded plate on the distal prolateral surface produced to short point ventrally. Bulb large, conductor and embolus as in Fig. 95. Tarsus with a sharp distal process.
Abdomen. Subspherical, spinnerets ventral. Ventral scute short, encircling petiolus, dorsal scute well developed, posterior in position. Six short spinnerets and small colulus in compact group. Mammillary ring absent.
Female. Measurements: Carapace—Length, 0.58; width, 0.48; height, 0.39. Abdomen—Length, 0.75; width, 0.67.
With the general characters of the male, but the head region appears to be more rounded. Abdomen without dorsal scute, ventral scute extending posteriorly. Palp absent.
Types. Holotype male, allotype female and paratypes, North Queensland, Mount Spurgeon, July 1932, P. J. Darlington. Holotype and allotype, Museum of Comparative Zoology, Cambridge, Mass, paratypes, Queensland Museum, Otago Museum.
Pseudanapis grossa n. sp. (Figs. 98–105.)
Male. Measurements: Carapace—Length, 1.09, width, 0.75; height, 0.54. Abdomen—Length, 1.24;, width, 0.84.
Colour. Cephalothorax and abdominal scutes deep reddish-brown. Legs paler brown. Abdomen blackish grey except for the pale dorsal area and a few pale spots.
Text-fig. 18.—Figs. 98–105—Pseudanapis grossa n. sp. Fig. 98—Body of male from side. Fig. 99—Carapace and chelicerae from in front, showing eyes. Fig. 100—Carapace from above. Fig. 101—Male chelicera. Fig. 102—Metatarsus and tarsus showing spur. Fig. 104—Retrolateral surface male palp. Fig. 105—Prolateral surface male palp.
Carapace (Figs. 98, 100). Smooth, head region rounded, much higher than thoracic region, with a prominent lobe on each anterior dorsal margin which bears the lateral eyes. Thoracic groove deep, limited to the median surface. There is a prominent ridge extending from below the head back down the thorax on each side near the lateral margins and curving in to the median line posteriorly where it extends forward as a single ridge to a point midway between the posterior margin of the thorax and the thoracic groove. There is a rounded lobe on each posterior corner of the thorax.
Eyes (Fig. 99). Six in three pairs. The lateral eyes are contiguous and are placed on a large prominent protuberance. Median eyes contiguous. When viewed from above, the posterior row is almost straight; from in front it appears strongly procurved. Ratio of ALE:PME:PLE = 10:9:11. The ALE are separated from each other by a distance equal to 11/2 the diameter of an ALE, while the PLE are separated from the PME by a distance equal to the diameter of an ALE.
Sternum. Slightly convex, joined to carapace by sclerotic strips passing between the coxae. Maxillae transverse and differentiated from broad band which passes from coxal anteriorly separating the chelicerae and maxillae. The pedipalps are inserted on this band. There is a stout erect spine on the undersurface of the maxillae. The posterior margin of the sternum is rounded and separates coxae IV by a distance equal to their width.
Chelicerae (Fig. 101). Vertical, with a rounded swelling on the proximo-dorsal surface which abuts onto a small lobe on each anterior corner of the carapace. Promargin with a
strong tooth on both proximal and distal extremities. Retromargin with a broad serrate process.
Palp. (Figs. 104, 105.) Trochanter and femur slender, elongate. There is a small rounded lobe on the distal retrolateral surface of the femur and a prominent bifurcate process on the prolateral surface of the patella. Bulb simple, embolus slender, conductor absent.
Legs 184.108.40.206. Leg 1 with a sharp spur on the disto-ventral surface of the metatarsus and two short spines on the distal proventral surface of the metatarsus and the proximal proventral surface of the tarsus (Figs. 102, 103). Legs 1–3 with 3(1.1.1) trichobothria along the median surface of tibia and one on metatarsus. Leg 4 with four (1.2.1) on tibia, metatarsus none. Three claws, smooth, inferior long and slender. Tarsal organ proximal.
Abdomen. Ovoid, spinnerets ventral, rising higher than carapace. Ventral scute small, encircling the petiolus. Dorsal scute large, posterior in position. Clothed with short hairs, which do not have conspicuous basal sclerites, but with a number of small round, non setose sclerites on the lateral surfaces.
Six short spinnerets and colulus in a compact group, without mammillary ring.
Type. Holotype male, New Guinea, Gomomgu Valley, Ramu-Purari Divide ca. 3 miles S.W. of Mount Otto, Central Highlands, 7,500ft, August 18, 1956, T. E. Woodward. (Holotype, Queensland Museum.)
Pseudanapis aloha n. sp. (Figs. 106–110.)
Male. Measurements: Carapace—Length, 0.75; width, 0.71, height, 0.53. Abdomen—Length, 0.96; width, 0.85.
Colour. Carapace, sternum and abdominal scutes yellow-brown. Legs paler brown. Unsclerotised portions of the abdomen pale yellow.
Carapace (Fig. 106). Slightly longer than wide. Lateral margins of thorax and head coaisely punctate. Posterior slope of thorax granulate, dorsal surface of head smooth and shiny. The thoracic region slopes steeply back, with low lateral shoulders. Cephalic groove shallow, but clearly defined. Head gently rounded, highest in the region of the eyes.
Eyes (Fig. 107). Six. Ratio of ALE:PME:PLE = 6:5:6. Lateral eyes and PME as contiguous pairs. When viewed from above the posterior row is gently procurved. PME separated from the PLE by a distance equal to the diameter of a PME. Clypeus, vertical, height equal to twice the diameter of the PME.
Sternum. Convex, coarsely punctate, joined to carapace by strips between the coxae. Broadly obtuse and gently rounded posteriorly between coxae 4 which are separated by a distance equal to almost twice their width. Labium fused to sternum, almost twice as wide as long. Maxillae transverse, narrowing to a sharp point distally.
Chelicerae (Fig. 110). With a pronounced proximo-dorsal swelling. Promargin with a three closely spaced teeth on the median surface and a single proximal tooth. Retromargin smooth. There is a row of eight ciliate hairs along the proventral surface.
Palp (Figs. 108–109). Femur short, with strong distodorsal bifid process. Patella elongate with a small median dorsal spine and a stronger distodorsal sinuous process. Cymbium oval, bulb as figured.
Legs. 220.127.116.11. Spines lacking Clothed with smooth hairs, except for a few on the ventral surfaces of the tarsi, which are finely serrate. There are three (2.1) trichobothria on the dorsal surfaces of the tibia of all legs and a single trichobothrium on the metatarsus of legs 1–3. Tarsal drum proximal. Three claws, with two false claws. Superior claws with a single ventral tooth.
Abdomen. Dorsal and ventral scutes well developed, both with scattered punctures. Dorsal plate clothed with relatively long, smooth hairs. Soft portions of the abdomen with longitudinal rows of small sclerotic plates. Six spinnerets and a small colulus enclosed by a prominent sclerotic ring. There appears to be no posterior spiracle. The two anterior spiracles open at the notches on the posterior lateral margins of the ventral scute.
Text-fig. 19.—Figs. 106–110—Pseudanapis aloha n. sp. Fig. 106—Side view body of male. Fig. 107—Carapace of male from in front, showing eyes. Fig. 108—Retrolateral surface of male palp. Fig. 109—Prolateral surface of male palp. Fig. 110—Male chelicera.
Type. Holotype male Hawaii, in collection, American Museum of Natural History, New York.
Pseudanapis wilsoni n. sp. (Figs. 111–117.)
Male. Measurements: Carapace—Length, 0.32; width, 0.29; height, 0.31. Abdomen—Length, 0.52; width, 0.46.
Colour. Cephalothorax, appendages and scutes dark reddish brown. Soft portions of abdomen grey.
Carapace. There are numerous punctures on the thoracic region and the dorsal surface of the head region. The head is somewhat higher than the thorax and from the side appears gently rounded, almost flat. Thoracic groove deep mesially, shallow laterally where it can be traced almost to the lateral margins. The thoracic region slopes steeply down to the posterior margin.
Eyes (Fig. 113). Six in three contiguous pairs. When viewed from above the posterior row is almost straight, when viewed from in front strongly procurved. Ratio of ALE:PME:PLE
Text-fig. 20.—Figs. 111–117—Pseudanapis wilsoni n. sp. Fig. 111—Side view body of female. Fig. 112—Ventral view body of female. Fig. 113—Carapace and chelicerae from in front, showing eyes. Fig. 114—Tibia of leg 1 of male. Fig. 115—Male chelicera. Fig. 116—Pro-lateral surface of male palp. Fig. 117—Retrolateral surface of male palp.
= 6:5:6 ALE separated from each other by a distance equal to 8/6 of the diameter of an ALE. ALE separated from the PLE by a distance equal to 3/6 of the diameter of an ALE.
Chelicerae (Fig. 115). Vertical, with a tricuspid tooth on the retromargin and a single tooth on the proximal promargin. There is a row of six ciliate hairs above the promargin and a further two similar hairs on the mid prolateral surface.
Sternum. Convex, coarsely punctate, scutiform, broadly obtuse posteriorly, separating coxae IV by distance equal to twice their width. Maxillae transverse. Labium fused, twice as wide as long.
Palp (Figs. 116, 117). Femur with two strongly curved spinous processes, one dorsal at two-thirds, and one on the subdistal prolateral surface. Patella somewhat flattened and projecting dorsally above the femur. Bulb simple, embolus long and ribbonlike, coiled 1½ times round the bulb, terminating with a sharp point at the posterior retrolateral surface. Conductor absent.
Legs. Clothed with smooth hairs. Tibia of leg 1 with three spines on the mid-ventral surface, two large and one small, followed by a ventral row of four spatulate spines and a proventral row of three normal spines (Fig. 114). Tibia of leg 2 with four ventral spines. Tibia of all legs with three trichobothria (2.1), metatarsi 1–3 with a single median trichobothrium. Tarsal drum proximal. Three claws, smooth.
Abdomen. Ovoid. Dorsal and ventral scutes present, dorsal scute smooth, ventral scute coarsely punctate, clothed with short hairs which rise from small sclerotic plates. Six spinnerets with colulus surrounded by a sclerotic ring.
Female. Measurements: Carapace—Length, 0.33, width, 0.32; height, 0.31. Abdomen—Length, 0.52; width, 0.56.
Dorsal scute absent but dorsal surface somewhat coriaceous. Internal genitalia simple. Abdomen consisting of a simple sac with a number of conspicuous round sclerotic plates near the lateral margins of the scute. Pcdipalps lacking. Legs without spines.
Types. Holotype male, allotype female, paratype female, New Guinea, Lower Busu River, Huon Peninsula, 1955, E. O. Wilson, ex leafmould lowland rain forest. Holotype and allotype, Museum of Comparative Zoology, Cambridge, Mass., para-type, Otago Museum.
Genus Patu Marples, 1951
This genus is closely related to Symphytognatha, from which it is mainly separated by the form of the chelicerae teeth. Marples (1951) has recorded two species, P. vitiensis from Fiji and P. samoensis from Samoa. Two further species are described below, P. marplesi from Samoa and P. woodwardi from New Guinea.
Patu woodwardi n. sp. (Figs. 118–123.)
Male. Measurements: Carapace—Length 0.19; width, 0.18; height, 0.15. Abdomen—Length, 0.33; width, 0.34.
Colour. Body and appendages dark grey, without markings.
Carapace (Fig. 118). Rising steeply from the posterior margin of the carapage, highest in the region of the eyes. Thoracic groove absent, smooth apart from a few hairs on the dorsal head region.
Eyes (Fig. 119). Six, relatively large. From above the posterior row is almost straight, from in front it appears strongly procurved. Ratio of ALE:PME:DPLE = 3.4.3. The PME are separated from each other and from the PLE by a distance equal to one-half of the width of a PME. Lateral eyes contiguous, placed on a definite tubercle. Clypeus slightly concave, equal in height to the diameter of a PME.
Chelicerae (Fig. 122). Vertical small, with a single stout tooth at the base of the fang.
Sternum. Convex, smooth and shiny. Almost as wide as long, obtuse behind where it separates the fourth pair of coxae by a distance equal to twice their width. Maxillae converging but not meeting in the midline. Labium wider than long.
Palp (Figs. 120–121). Without lobes or processes. Tarsus twisted so that bulb is retrolateral. Embolus slender, coiled around prolateral surface to a short spinous conductor which is situated dorsally. There is a further short spinous structure ventrally.
Legs 18.104.22.168. Clothed with smooth hairs and bristles present on the dorsal surfaces of patella and tibiae. Spines lacking. Trichobothria present only on the tibiae of all legs. Three (1.2) on tibiae 1–3, four (1.2.1) on tibia 4. Tarsal drum proximal. Three claws, all of which appear smooth.
Abdomen. (Fig. 118). Globose, clothed with slender smooth hairs. Six spinnerets with large colulus, ventral in position.
Female. Measurements: Carapace—Length, 0.23; width, 0.21; height, 0.13. Abdomen—Length, 0.38,;width, 0.36.
Very similar to the male in most characters. The palp is completely absent. Internal genitalia as shown in Fig. 123. Legs 22.214.171.124.
Types. Holotype female, paratype female, New Guinea, Lae, ex leafmould rain forest, August 6, 1956, T. W. Woodward; allotype male, Benage, ca. 20 miles S.W. of Aiyura, East Highlands, ca. 6,000ft ex leafmould rain forest, August 1, 1956, T. E. Woodward. Holotype female, allotype male in Queensland Museum; paratype female in Otago Museum.
Patu marplesi n.sp. (Figs. 124–127.)
Male. Measurements: Carapace—Length, 0.22; width, 0.22; height, 0.13. Abdomen—Length, 0.21; width, 0.22.
Colour. Entire spider pale yellow, without markings.
Carapace (Fig. 124). Rising steeply from the posterior margin to the highest point about mid-length from where it slopes gently to the eyes. Lateral eyes on lobe. Clypeus somewhat concave.
Eyes (Fig. 124, 125). Six. From above the posterior row is slightly recurved. All eyes equal in width, relatively large, occupying the full width of the eye region. ALE separated from each other by a distance equal to three times their width, PME subcontiguous, separated from the PLE by a distance equal to half of the width of an ALE.
Chelicerae. There appears to be a single tooth near the base of the fang.
Sternum. Convex and smooth, broadly obtuse behind where the fourth pair of coxae are separated by twice their width.
Palp (Figs. 126, 127). Short curved embolus present on prolateral surface. There is a short stout conductor on the distal prolateral surface and a more blunt lobe and a small bifid tooth on the distal retrolateral surface.
Legs 126.96.36.199. Spines absent. Three trichobothria on tibiae of legs three pairs of legs, four on tibia 4. No trichobothria on metatarsi. Three claws, tarsal organ basal.
Abdomen. Ovoid, clothed with relatively long, smooth hairs. Six spinnerets and colulus.
Type. Holotype male Western Samoa, Malololelei, Upolu, ca. 2,000ft, ex moss, January, 1956, T. E. Woodward. Queensland Museum.
Remarks. This species is separated from vitiensis and samoensis by the ovoid abdomen and the unidentate cheliceral tooth. It may be distinguished from woodwardi by the different shape of the cephalothorax and the form of the male palp.
Genus Anapistula Gertsch 1941
Anapistula australia n.sp. (Figs. 128–132.)
Female. Measurements: Carapace—Length, 0.25; width, 0.22; height, 0.08. Abdomen—Length, 0.38; width, 0.39.
Colour. Entire animal pale creamy white except for a black ring surrounding the eyes.
Carapace. Relatively low, highest behind the eyes, where the height is equal to little more than one-third of the width. Lateral margins evenly rounded, thoracic groove lacking.
Eyes (Fig. 128). Four. Lateral eyes only present in a contiguous pair at each laterodorsal margin. They are separated from each other by a distance equal to eight times the diameter of an ALE. The clypeus is somewhat concave, height equal to slightly more than twice the diameter of an ALE.
Chelicerae (Fig. 129). Vertical, possibly fused at their base. There is no trace of a furrow, but with two strong teeth near the base of the fang. The fang is relatively short and stout.
Sternum. Slightly convex, as wide as long, truncate behind, where coxae 4 are separated by a distance equal to twice their width. Maxillae transverse with well developed serrula. Palp lacking.
Legs 188.8.131.52. Clothed with slender, smooth hairs. Tibia of all legs with three trichobothria, metatarsi of legs 1–3 with a single trichobothrium, none on metatarsus of leg 4. Tarsal drum proximal. Three claws, all of which appear smooth.
Abdomen. Globose, without scutes, clothed with smooth hairs. Epigynum as in Fig. 131. Internal genitalia as in Fig. 132.
Type. Holotype female. Australia: S.E. Queensland, Camp Mountain, ex litter on sand beside creek, December 26, 1956, T. E. Woodward (Queensland Museum).
Respiratory System of the Symphytognathidae
The numbers and placing of the external openings of the respiratory system in spiders has long been used in systematic grouping, but it is only comparatively recently that the internal structure of the respiratory system has been extensively
Text-fig. 23.—Figs. 128–132—Anapistula australia n.sp. Fig. 128—Dorsal surface of carapace. Fig. 129—Chelicera of female. Fig. 130—Colulus. Fig. 131—Female epigynum. Fig. 132—Internal genitalia.
studied and used as a basic character in an attempt to elucidate phylogeny within the order. In 1933 Professor Alexander Petrunkevitch published the results of an extensive survey of both the internal and external structure of the spiders and set out an overall classification in keeping with his findings. The Symphytognathidae he placed with the Caponiidae and Telemidae into a separate suborder, the Apneumonomorphae. Subsequent authors (Bristowe, 1938; Fage, 1937) have disagreed with this conclusion, maintain that the apneumone families do not form a natural assemblage and group the families with dipneumone families.
The sub-order Apneumonomorphae is based primarily on two internal characters which all these spiders have in common. These are the absence of anterior lungbooks and their replacement with tracheae, and the presence of only two pairs of ostia. The reduction in number of ostia is also found in other families of spiders leaving the absence of lungbooks and their replacement with trachea the only character unique to the three families. It would therefore seem that the only justification for a separate suborder would be if it could be postulated that the loss of the
anterior pair of lungbooks and their replacement with trachea happened only once during the common development of these families. Recent work by Fage and Machado (1951) and Machado (1951) on the Ochyroceratidae has demonstrated that in this family there are genera with a pair of anterior lungbooks and others which are without lungbooks. An examination of the respiratory system of the spiders studied in the present paper in conjunction with the results published by other authors convinces me that a similar situation exists in the Symphytognathidae and that there is little justification other than convenience for placing this family into a separate suborder with the Caponiidae and Telemidae. The difficulty expressed by Petrunkevitch in imagining a sudden change from functional lungbooks to equally functional tracheae is hard to understand. The functioning of the lungbooks and the tracheae of spiders, from the information available, would appear to be similar if not identical. Oxygen transfer is achieved through the walls of these structures to oxygenophylic bodies, which then carry the oxygen to the structure requiring it, a condition in contrast to insects where oxygen transfer is considered to take place directly from the tracheoles to the tissue and is correlated with the absence of oxygen carrying pigment in the blood. The gradual elongation of the lamellae of lungbooks and reduction in the width of the lumen would lead directly to a structure having the form and presumably the function of a tracheal system without any question arising of a hiatus in the efficient use of these structures in the respiration of the spider. That this is in fact what has happened is, I feel, indicated by the structure of the anterior respiratory system of Risdonius, Archerius and some species of Mysmena (Levi, 1956) where it is difficult to decide on morphological grounds whether the structures present should be termed modified lungbooks or a tracheal system. It therefore seems reasonable to assume that the change from lungbooks to tracheae has taken place a number of times and that the change is governed by physiological factors.
The tendency for lungbooks to be replaced by tracheae is of considerable general interest. Davies and Edney (1952) during their study on the evaporation of water from spiders demonstrated that in Lycosa amenta respiration took place mainly through the lungbooks, and that tracheal respiration alone was not sufficient to keep the spider alive. If, as might be concluded from these experiments that the lungbooks are the more efficient respiratory organ, it seems surprising that the overall evolution of the spiders indicates a progressive loss of these structures. It is perhaps significant that all of these spiders which we know have lost the anterior pair of lungbooks are small and with the exception of the Caponiidae are in fact minute. It is probable that with the reduction in size and the increase of surface area in relation to body volume, water loss becomes an increasingly important factor influencing changes in the respiratory system because the water loss from lungbooks could be much greater than from tracheae. Most of these spiders are found only in habitats where there is a constant high humidity and are difficult to keep under laboratory conditions for this reason. Furthermore, there is a tendency for many of them to possess sclerotic thickenings and plates on the abdomen which possibly reduce transpiration through the integument.
The respiratory system now known for the species placed in the Symphytognathidae covers a wide range, with a certain degree of uniformity at a generic level. If, as is most probable, the loss of a structure such as the posterior tracheae, the fusion of two spiracles into a single median one, or the change from lungbooks to tracheae, precludes the future reappearance of these structures in their earlier form, it is necessary to postulate an ancestral form which possessed one pair of lungbooks and two posterior spiracles leading into tracheae. The only living spiders which possess this arrangement are those placed in the families Dysderidae and Oonopidae, neither of which show very close relationship when other characters are considered. If, as is suggested in the present paper, these spiders have developed from the Argiopidae or as a number of other authors have suggested, the Theridiidae, then
Text-fig. 24.—Figs. 133–141—Respiratory systems as seen from above (anterior tracheae stippled). Fig. 133—Risdonius parvus Hickman, male. Fig. 134—Risdonius conicum (Forster) female. Fig. 135—Micropholcomma caeligenus Crosby and Bishop, female. Fig. 136—Micropholcomma parmata Hickman, female. Fig. 137—Micropholcomma longissima (Butler), male. Fig. 138—Pua novaezealandiae n.sp., female. Fig. 139—Textricella tropica n.sp. female. Fig. 140—Textricella pusilla, female. Fig. 141—Parapua punctata n.sp. female.
we must look for forms within these families which still possess a pair of posterior spiracles. As far as I am aware none has been recorded but this does not preclude the actual existence of such forms either among the smaller known species or in forms at present not known. It would, however, be in no way surprising if this character has in fact been completely lost since the divergence of the Symphytognathidae from the parent stock in view of the number of forms this system takes within the Symphytognathidae and the overall indication that there is a tendency for the two posterior spiracles to merge into one.
Mysmena appears to have retained the primitive arrangement more consistently than other genera. Mysmena guttata (Banks) and Mysmena phyllicola (Marples) possess modified lungbooks, while the two posterior spiracles open into tracheae. In M. incredula (Gertsch and Davis), M. woodwardt n.sp. (Fig. 147), M. rotunda (Marples) and M. samoensis (Marples) (Fig. 148a) the anterior spiracles lead into tracheae which are discrete in woodwardt but joined by a transverse duct in other species. The two posterior spiracles in all these species lead into atria which are
Text-fig. 25.—Figs. 142–148—Respiratory systems (anterior tracheae stippled). Fig. 142—Chasmocephalon armatum, Forster. Fig. 143—Chasmocephalon minutum Hickman (from Hickman, 1944). Fig. 144—Symphytognatha globosa Hickman, female (from Hickman, 1931). Fig. 145—Chasmocephalon sp. ? Capetown (from Fage, 1937). Fig. 146—Patu Marples, female. Fig. 147—Mysmena woodwardt n.sp. immature female. Fig. 148—Mysmena vitiensis n.sp., female. Fig. 148A—Mysmena samoensis (Marples).
connected transversely and from each atrium tracheal tubes run through into the cephalothorax. In Mysmena vitiensis (Fig. 148), however, the anterior atria are not joined, and there appears to be a single median spiracle midway between the spinnerets which leads into four tubes, which do not enter the cephalothorax. The general pattern found in Patu is that illustrated for P. vitiensis (Fig. 146). The anterior spiracles lead into large atria which are connected transversely and tracheae from these atria supply both the cephalothorax and the abdomen. This is similar to the system found in Symphytognatha (Fig. 144). However, an undescribed species from Poutasi, in Western Samoa, which is undoubtedly a typical Patu, possesses two spiracles which are midway between the spinnerets and the epigastric groove as in most species of Mysmena. These lead into short atria which are joined transversely, and from each atrium numerous tracheae pass directly through to the cephalothorax as they do in Mysmena. The anterior spiracles in Risdonius lead into tubular atria which are not connected transversely; from the inner surface of these tubes extend a number of evenly spaced structures which in R. parvus Hickman (Fig. 133) have the appearance of modified lamellae and have been described as such by Hickman (1939), but which in R. conicum (Forster) (Fig. 134) are more elongate and tubular and have more the appearance of tracheae. In both of these species there is a single posterior spiracle at the base of spinnerets which opens into a short atrium from which runs three or four tracheae limited to the abdomen. In Chasmocephalon the anterior spiracles open into short atria from which tracheae are supplied to both the abdomen and the cephalothorax. In C. minutum Hickman (Fig. 143) and an undescribed species from Capetown examined by Fage (Fig. 145) there is no posterior spiracle, but in the New Zealand species C. armatum (Forster) (Fig. 142) the posterior spiracle is present at the base of the spinnerets and this leads into four tracheal tubes which are limited to the abdomen.
The tracheal system of Anapistula (Fig. 158) is very similar to that found in Mysmena. There are two pairs of spiracles; the anterior pair lead into short atria which are connected by a transverse tube, from each atrium five or six tubes extend throughout the abdomen. The posterior pair of spiracles are situated midway between the epigastric groove and the spinnerets and lead into short atria which are connected by a transverse duct while a thick bunch of tracheae run from each atrium directly to the cephalothorax.
Fage (1937) examined the respiratory system of Anapis hamigera (Simon) and found that the single posterior spiracle which is placed between the spinnerets and the epigastric groove leads into a short vestibule from which runs two pairs of large trunks. The numerous fine tracheae from these trunks were limited to the abdomen. The two anterior spiracles lead into a wide transverse vestibule which was broken up at each outer margin into two trunks passing through the petiolus to the cephalothorax. In Anapis mexicana Forster (Fig. 157) the position of the spiracles is the same, but the posterior spiracle is present as a broad slit which leads into a short atrium from which two bunches of tracheae lead directly into the cephalothorax while the tracheae from the anterior spiracles are limited to the abdomen. The system for Anapisona gertschi Forster (Fig. 155) is similar to A. mexicana Forster except that the posterior spiracle is placed at the base of the spinnerets. In Pseudanapis only the anterior spiracles are present. Pseudanapis algerica Simon (Fig. 156), P. relicta Kratochvil (Fage, 1937), P. octocula n.sp. (Fig. 152), P. burra n.sp., P. insula (Forster) (Fig. 153), and P. wilsont n.sp. (Fig. 154) all have bunches of tracheae passing through the petiolus to the cephalothorax, but in P. darlingtoni n.sp. (Fig. 150) and P. spinipes (Forster) (Fig. 151) the tracheae are limited to the abdomen and the atria are very long and tubular. In both of these latter two species the spiracles have moved anteriorly and open near the petiolus. There is a transverse connecting duct present in P. algerica, P. relicta and P. insula, but this duct is absent from all other species examined
Text-fig. 26.—Figs. 149–158—Respiratory systems (anterior tracheae stippled). Fig. 149—Lucharachne palpalis, Krauss, female. Fig. 150—Pseudanapis darlingtoni n.sp., female. Fig. 151—Pseudanapis spinipes (Forster). Fig. 152—Pseudanapis octocula n.sp., male. Fig. 153—Pseudanapis insula (Forster), male. Fig. 154—Pseudanapis wilsoni n.sp., female. Fig. 155—Anapisona gertschi Forster, male. Fig. 156—Pseudanapis algerica, Simon, female (from Fage, 1937). Fig. 157—Anapis mexicana Forster, male. Fig. 158—Anapistula australia, n.sp., female.
Lucharachne palpalis Krauss (Fig. 149) is also without lungbooks and the system for this species is almost identical with that of Anapis hamigera, with the anterior spiracles providing tracheae to the cephalothorax as well as the abdomen. The posterior spiracle, however, is situated at the base of the spinnerets, and appears to have two small openings placed very close to each other, which open into a common atrium. In Micropholcomma (Figs. 135, 136, 137) the two anterior spiracles lead into large atria which are joined by a transverse duct. From the atria a number of trunks are limited to the abdomen, but a single pair pass through the petiolus and branch into numerous fine tracheae in the cephalothorax. The single posterior spiracle is situated at the base of the spinnerets and leads into a short atrium from which runs two or four short tracheae. Pua and Parapua are without a posterior spiracle, but the anterior tracheal system in Pua novaezealandiae n.sp. (Fig. 138) is the same as in Micropholcomma except that the transverse duct is absent. In Parapua punctata n.sp. (Fig. 141) a bunch of five fine tracheae pass through the petiolus in place of the single trunk in the other two genera. Textricella (Figs. 139, 140) is also without a posterior spiracle, but the tracheae from anterior spiracles are limited to the abdomen.
The overall picture appears to be one of active change in the form of the respiratory system within the family at a generic level. Only in Mysmena does there appear the original arrangement with two posterior spiracles leading into tracheae and two anterior spiracles leading into lungbooks and even in these species the lungbooks are not typical of other spiders. The changes appear to follow a fairly set pattern with, first, the modification of the anterior lungbooks into tracheae, then the fusion of the two posterior spiracles into a single median spiracle, which is then situated posteriorly at the base of the spinnerets in contrast to the placing of the two original spiracles, which are usually situated midway between the epigastric groove and the spinnerets. An intermediate stage is illustrated in Lucharachne where the posterior tracheae open from the base of the spinnerets through two openings placed on a common plate. The ultimate form is found when the posterior spiracle is lacking leaving the two anterior spiracles leading into tracheae as the sole respiratory organ. At this stage there appears to be a tendency for the spiracles to move anteriorly beyond the epigastric groove as in Pseudanapis spinipes and P. darlingtoni.
In most genera tracheae are supplied to the cephalothorax from either the anterior or posterior spiracles, and in no case have tracheae been recorded penetrating to the cephalothorax from both. In eight of the genera examined (Symphytognatha, Patu, Micropholcomma, Pua, Parapua, Chasmocephalon, Pseudanapis and Lucharachne) tracheae from the anterior pair of spiracles supply both the abdomen and the cephalothorax, but in two species of Pseudanapis (spinipes and darlingtoni) the anterior tracheae are limited to the abdomen. In four of the genera (Mysmena, Anapistula and Anapisona) tracheae are supplied to the cephalothorax from the posterior spiracles and except in Anapisona all of the trachea pass directly through the petiolus to the cephalothorax. In only two genera (Risdonius and Textricella) are tracheae not present in the cephalothorax. The presence in some species of a transverse tube connecting the atria is interesting, and may be found to have some significance, although from the data available at present this does not appear to be so. A similar duct joins the lungbooks of many dipneumone spiders.
The distribution and origin of the tracheae to the abdomen and cephalothorax has been used as a major character in the separation of the families previously placed in the Apneumonomorphae, but it now seems that this has little significance beyond a generic level and can vary within a genus.
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Dr. R. R. Forster,
The Life History of the Common New Zealand Skink Leiolopisma zelandica (Gray, 1843)
[Received by the Editor, March 6, 1958.]
In a study area of a quarter acre, a population of at least 222 lizards was determined by marking and recapture over a two-year period. The species Leiolopisma zelandica is described. Variation in numbers of head plates and body scales and in relative proportions is determined. The testes are at minimal mass in June-July, enlarging during summer. Copulation is described. Ovulation occurs in October, gestation is twelve weeks, parturition is in January. Three to five young are born per female. Earlier ovulation and two young per female are shown by Leiolopisma aeneum.
The young increase two and a-half times in weight before hibernating when growth ceases. In the next growing season the young reach small adult size at 16 months and become sexually mature at 20 to 21 months. Growth continues throughout life, becoming progressively slower. Young in their first year form the only distinct age-size class. Sixty-five per cent of captures had broken or regenerating tails which are rarely as long as the original and have different scalation. Food was in order of preference spiders, hemipterans, coleopterans, isopods and amphipods. One-third of the lizards examined were infected rectally with a nematode Pharyngodon sp.
L. zelandica has a definite home range of about 15 square yards; home ranges overlap considerably. Aggressive territorial behaviour was not observed. Juveniles show no home range behaviour. In Wellington only partial hibernation occurs; the period is four and two-thirds months. Moulting was observed in October-November and is completed within 24 hours, the epidermis being shed in patches.
The small brown skink Leiolopisma zelandica (Gray, 1843) is perhaps the most abundant and widely distributed New Zealand reptile. It is therefore remarkable that the life history and habits of this lizard, known since the days of New Zealand's first explorers, have never been more than casually discussed. Indeed, few facts have been recorded concerning the habits, ecology or life history of any New Zealand lizard.
Leiolopisma zelandica was first described by Gray in 1843 as Tiliqua ornata from material collected by Ernst Dieffenbach during his travels as naturalist to the New Zealand Company. Gray's description was incorporated in Dieffenbach's “Travels in New Zealand” and subsequently in the “Catalogue of Lizards in the Collection of the British Museum” which Gray published in 1845. Numerous changes of name and position were later accorded to the species, which was included in Boulenger's great Catalogue of 1887 as part of the species Lygosoma moco. McCann (1955) distinguished and redescribed Leiolopisma zelandica as a valid species in his recent revision of the lizards of New Zealand.
The genus Leiolopisma has a wide distribution; Asia, North and Central America, Australia, and New Zealand. No extensive account of any member of the genus has yet appeared. Lewis (1951) described some aspects of the biology of Leiolopisma laterale (Say) which occurs in the eastern and southern United States. Breckenridge (1943) and Fitch (1954) have carried out detailed studies on the life histories of two oviparous scincid lizards, both of the genus Eumeces. The most comprehensive of these accounts is that by Fitch, who studied the life history and
ecology of Eumeces fasciatus (Linnaeus) over a five-year period. The life history of Leiolopisma zelandica is not entirely comparable with that of skinks studied in detail by previous workers, since the species is viviparous. So far as is known, the present study is the first to appear on a viviparous skink.
Leiolopisma zelandica is a quietly moving, wary lizard, secretive in its habits and usually seen moving in a normal manner only when the observer remains still and quiet in one spot. The species lives in almost any small area offering sufficient cover, moisture, food, and sunlight. Almost every city garden, coastal beach and shingle river bed has a skink population. Where suitable habitats are present, the species occurs well inland, although it is generally more plentiful in coastal areas. Under optimum conditions local populations may be very large, far larger than is apparent to the casual observer.
New Zealand does not have a very diverse fauna, and the skink has few direct competitors. This, together with the absence of a wide range of skink predators, means that skinks are relatively secure animals capable of forming dense local populations.
The study presented here has been primarily a field one, carried out to determine the main features of reproduction, growth habits and behaviour, and was conducted in an area containing what proved to be a denser population of Leiolopisma zelandica than was originally anticipated. This area lies within the limits of the city of Wellington and was sufficiently close to the university to allow field observations to be made at regular intervals. The study commenced in March, 1954, and was continued to October, 1955, the period being long enough to obtain information on many aspects of the natural history of Leiolopisma zelandica, the common brown skink.
Description and Variation
McCann (1955) describes all the known members of the New Zealand Scincidae, including Leiolopisma zelandica (Gray, 1843), and Leiolopisma aeneum (Girard, 1857) and discusses in detail the synonymy of the New Zealand species. The description given below of Leiolopisma zelandica is based upon an examination of 50 specimens from several localities in the Wellington district, and is more detailed than that of McCann. Specimens of L. zelandica were collected from Kelburn, Brooklyn, Island Bay, York Bay, and Somes Island, all close to Wellington City, and from Pukerua Bay, 18 miles north of the city.
Leiolopisma zelandica (Gray, 1843)
Habitat lacertiform; snout short, profile moderately obtuse, anterior ⅔ head contour is wedge-shaped, posterior ⅓ parallel-sided, passing evenly to moderately elongate body; limbs well-developed. Undamaged tail length 1.0 to 1.2 the distance between snout and vent. Distance between tip of snout and fore-limb 1.2 to 2.0 (2.0 +) in the distance between the axilla and groin.
Rostral moderately large (Text-fig. 1); dorsolateral margins excavate and with posteroventral wings below on each side, the area visible from above being slightly more than ½ of the area of the frontonasal; twice as broad as long; short convex median junction with the frontonasal about equal to ⅙ the width of the frontal; long, concave sutures with the nasals; short vertical sutures with the 1st upper labials. Nasals moderate, narrowly separated by rostral-frontonasal suture; irregularly pentagonal; horizontal suture with upper edge of 1st upper labial and forward edge of anterior loreal. Nostril pierces centre of nasal. No supranasals or postnasals. Anterior loreal rhombic, posterior border against posterior loreal; ventral against 2nd upper labial and dorsal narrowly contacts frontonasal and still less the prefontal. Frontonasal large, diamond-shape, about equal in area to frontal from which it is excluded by the median junction of the prefrontals; narrowly in contact with
Text-fig. 1.—The head plates of Leiolopisma zelandica. (1) Lateral view head plates. (2) Dorsal view head plates. (3) Ventral view chin shields. Key: AL, anterior loreal; C, chinshields; F, frontal; FN, frontonasals; FP, frontoparietals; GU, gulars; IP, interparietal; LL, lower labial; M, mental; N, nasal; NU, nuchals; P, parietal; PF, prefrontal; PG, postgenials; PL, posterior loreal; PLA, post labials; PM, post mental; PO, preocular; POC, postocular; PS, presuboculars; PT, primary temporal; R, rostral; SC, superciliaries; SO, supraoculars; ST, secondary temporals; TT, tertiary temporals; UC, upper ciliaries; UL, upper labials.
nasals and prefrontals. Prefrontals large, each equal to ⅗ the area of the frontal; irregularly elongate ovoid; convex sutures with frontal and 1st supraocular; shorter sutures with anterior loreal and preocular. Frontal large, kite-shaped, length equal to its greatest width; wider than supraocular region; longest sides against 1st and 2nd supraoculars, short convex sutures with frontoparietals. Frontoparietals paired, right longer than left; longest sutures with each other then next in length with interparietal; shallowly concave sutures with the 2nd, 3rd and 4th supraoculars; concave sutures with parietals. Interparietal kite-shaped; smaller than frontal; enclosed between frontoparietals and parietals; pineal area apparent just behind midpoint of shield. Parietals largest head shields, as long as frontoparietals and interparietals together; irregular oblongs, long axes of each shield diverge from each other at about 80°, more than twice the length of the short axis; parietals meet in a short suture sloping back towards the left; other sutures, long and straight with uppermost secondary temporal, less long with the interparietal, still less with the frontoparietal and first nuchal and considerably shorter with the 4th supraocular, 1st and 2nd postoculars; the right parietal shield also narrowly meets the first nuchal on the left side. One to five, usually three pairs of nuchals, rarely more, often extra unpaired nuchal, each twice width of the dorsal scales, with which they often gradually merge.
Six to nine, usually seven upper labials; 1st small, square, in contact with nasal dorsally; 2nd, 3rd and 4th similarly shaped, slightly larger and higher; 2nd in contact with both loreals, 3rd with posterior loreal and presuboculars; 5th larger
than preceding four, immediately below centre of eye, 6th and 7th taller than 5th. Two large postlabials are separated from ear opening by 2 small projecting lobules. Three postoculars. Primary temporal, roughly hexagonal bordering the second upper postocular, lower postocular, upper and lower secondary temporal, 6th and 7th upper labials. Upper secondary temporal twice the size of the primary temporal, larger than the lower secondary temporal. The two tertiary temporals are a little larger than the following body scales. Body scales begin behind the nuchals, tertiary temporals and posterior postlabials.
The paired loreals are moderate, subequal in size, irregularly quadrilateral; the anterior lying between the nasal, frontonasal, prefrontal, posterior loreal and 2nd upper labial; the posterior loreal bordered by the prefrontal, preocular, 1st presubocular and 2nd and 3rd upper labials. Single preocular, 3 presuboculars, 1st largest, 3rd smallest. Eye completely surrounded by elongate rectangular granules, forming above a row of 5 or 6 supraciliaries, with a similar number below. Lower eyelid, with an undivided, transparent palpebral disc about as large as the ear opening surrounded by small oblong granules. The eye is bounded above by a row of 7 or 8 superciliaries; below by 3 presuboculars, 5th and 6th upper labials, 1st upper postocular and lower postocular. The superciliaries are bordered anteriorly by the preocular; above by 1st to 4th supraoculars; posteriorly by the 1st upper postocular. Four well developed supraoculars, 2nd largest; then 1st, 3rd and 4th in turn.
Mental shield larger than rostral, postmental 1½ times the size of mental; followed by 3 pairs of chinshields; the first pair are in contact, the second pair separated by a single scale row, the third by 3 scale rows. Six lower labials, the 3rd, 4th and 5th being the largest.
Ear opening round or oval, about as large as palpebral disc, with 3 auricular lobules projecting feebly from its anterior border. Scales 28 to 32 at midbody, feebly striate, dorsals largest. Preanals, inner two largest. Limbs well developed, hind-limbs longer than fore-limbs; adpressed limbs meet, just fail to meet or overlap; fore-limb reaching rear corner eye opening or below centre of eye; pentadactyle; digits slender, subcylindrical, subdigital lamellae smooth, 20 to 25 under 4th toe hind-limb. Palms and soles granular.
Ground colour yellowish-brown, varying from a pale-straw colour to a strongly melanistic brown; dorsal scales have 4 or more black lines on their surface giving a striate appearance. Median longitudinal stripe, 2 half scale rows wide, partially or well-developed, commencing at nuchals and passing back over the first third of tail, frequently bordered by a narrow straw-coloured stripe; passing to a wide dorsal band, 2½ scale rows wide, yellow-brown with a well-defined lateral border. A fine dorsolateral light line 2 half scale rows wide, commencing above the anterior border of the eye and carrying backwards along either side of the tail, with a well defined lateral border (formed by a very dark brown lateral band).
A prominent broad lateral band 1 and 2 half to 2 and 2 half-scale rows wide, dark brown in colour, originating at the tip of the snout, passing through the eye and terminating towards the end of the tail, regularly notched above and below by lighter coloured scales extending into it, broken into irregular blotches or flecked with black and white spots; below this a very light yellow-brown stripe, one half to 1 scale row wide passes from beneath the anterior border of the eye through ear, above limb insertions, to the tail, irregularly defined below by sparsely pigmented scales which merge gradually with the even greenish-yellow ventral colouration, which also extends over the ventral surface of the limbs.
Any or all of the longitudinal stripes may become indistinct over the posterior third of the tail. Regenerated tail often dark orange-brown colour distinct from any other body colour. The fore and hind-limbs show the typical yellow-brown colour of the broad dorsal bands; frequently a narrow light-straw coloured stripe passes from the limb origin along the anterior face of the limb to the manus or pes, sometimes showing as a series of irregular blotches.
In an endeavour to detect body colour and pattern changes, the colouration of 26 newly-born juveniles was recorded in detail; as yet none of these lizards has been recaptured. The newborn are similarly patterned to the adult, with no distinctive juvenile colouration. The light-straw colour of the juveniles of L. zelandica gives way to a darker brown ground colour in large adults, generally with less distinct body striping.
Table I, based upon an examination of 50 L. zelandica of 35.0 mm or more from snout to vent, shows the variation encountered in several characters. The number of upper and lower labials, nuchals, scales around the middle of the body and subdigital lamellae under the 4th toe hind limb, vary. The number of lower labials varies more than the number of upper labials, 7 being the usual number in each case; two exceptions were found in this number in the upper labials and 20 exceptions in the lower labials. The number of nuchals varies from 1 to 5, though in one specimen they were entirely lacking. An even number was present in 26 specimens, 19 had one extra nuchal and four had 2 extra nuchals. In 23 lizards, 3–3 or 2–3 nuchals were present, these being the most frequent arrangements occurring. The number of scales round the middle of the body ranges from 28 to 34, with 29 or 30 in two-thirds of the specimens examined. The subdigital lamellae under the 4th toe hind limb vary in number from 20 to 24, being 20, 21 or 22 in three-quarters of the lizards examined. Detailed examination has failed to show that the variation listed above is the product of sex or age differences.
The ratio, snout-forelimb length to axilla-groin length, shows that there is a tendency for increased relative torso length in adult lizards. This is also reflected in the adpressed limbs, which may overlap, meet, or fail to meet. The adpressed limbs of adult lizards 48.0 mm or more from snout to vent fail to meet more frequently than those of sub-adult and juvenile lizards. The ratio, snout-forelimb length to axilla-groin length, for 22 lizards of 47.9 mm or less from snout to vent is 1.2 to 1.7; and for 43 lizards of 48.0 mm or more, 1.4 to 2.2. Sex differences were observed, such as a relatively broader head in males over 55.0 mm in snout-vent length, but the sample available was unsuitable for study of sex variations since it contained only 30% of males
The Study Area
Shortly after the commencement of this study a large population of Leiolopisma zelandica was found to be present in an abandoned cemetery adjacent to Victoria University. The area was an obvious choice as a site for a marking programme because of its close proximity to the laboratory, which allowed frequent observations to be made. It is overgrown by introduced and indigenous trees, shrubs and weeds, and is roughly triangular in shape, lying along the top and southern slopes of a small ridge running in a north-easterly direction towards Wellington Harbour. The surrounding land has been modified to some extent by roading and building excavations that form steeply sloping banks 3 feet to 25 feet high, dropping to paths or roads which border the cemetery on all three sides.
The top of the ridge lies some 300 feet above sea-level, falling to 250 feet at its most northerly point. Sloping away from the upper ridge is a small gully with a south-east aspect whose floor lies about 30 feet below the ridge. The narrow ridge-top strip is open to the sun, whereas the gully is shaded at all times by a thicket of trees and shrubs. The ridge is fully exposed to the two prevailing winds—i.e., from the north and the colder southerly wind.
|Labials. n = 50.||Nuchals. n = 50.|
|No. Upper Labials.||No. Lower Labials.||Paired = 27 indiv.||Unpaired = 22 indiv.|
|No. of Labials or Nuchals.||7||8||9||6||7||8||0+0||1 + 1||2 + 2||3 + 3||4 + 4||1 + 2||1 + 3||2 + 3||3 + 4||3 + 5||4 + 5|
|Frequency. (No. of Specimens.)||48||1||1||16||30||4||1||5||4||16||1||2||3||12||3||1||1|
|Scales Round Mid-body. n = 50||Subdigital Lamellae 4th toe, hind limb. n = 48|
|No of Scales or Lamellae.||28||29||30||31||32||33||34||20||21||22||23||24|
|Frequency. (No. of Specimens.)||7||18||15||3||6||—||1||10||14||13||5||6|
|Relationship of Adpressed Limbs.||Ratio. Snout to Fore-limb Length: Axilla to Groin Length.|
|Snout-vent length in mm.||Do Not Meet||Meet||Overlap||1.2||1.3||1.4||1.5||1.6||1.7||1.8||1.9||2.0||2.1||2.2|
Text-fig. 2 is a detailed plan of the ridge-top section in which the majority of skinks were marked. The quarter-acre plot is rectangular in shape, 180ft long by 60ft wide, with the longest dimension lying in a north-east to south-west direction, and comprises about one-third the total area of the cemetery. Over two hundred skinks of the species Leiolopisma zelandica were caught and marked within this narrow strip during the period from March, 1954, to October, 1955.
The graves of the cemetery, mostly surrounded or covered with concrete or brick, provide a litter of flat stones and bricks giving adequate cover to the skink population. There are numerous crevices in the stonework and narrow spaces which harbour many skinks, especially during the hibernation period. Many of the graves are bordered by a profuse growth of weeds and shrubs which either completely obscures the stonework or leaves “islands” of concrete which serve as basking places for L. zelandica.
The substratum consists of a thin layer of clay-loam varying in thickness from 2 to 10 inches, and overlying the typical mixture of rotten rock and clay produced through the decay of greywacke rock.
The trees of the area include both introduced and indigenous species. The indigenous species are: coprosmas (Coprosma repens and C. lucida), akeake (Dodonea viscosa), ngaio (Myoporum laetum), puriri (Vitex lucens), pohutukawa (Metrosideros excelsa), mahoe (Melycitus ramiflorus), karo (Pittosporum crassifolium), tarota (Pittosporum eugenioides), kowhai (Sophora tetraptera) and the New Zealand cabbage tree (Cordyline australis).
A few specimens of holly (Ilex aquifolium) with single specimens of yew (Taxus baccata) and Viburnum odoratissimum make up the introduced trees within the plot, although there are many more in the southern hollow. Grasses, predominantly brome (Bromus cartharticus) with some cocksfoot (Dactylis glomerata), Yorkshire fog (Holius lanatus), couch grass (Agropyron repens) and brown top (Agrostis tenuis) carpet the area in patches, mixed with weeds. Common amongst the weeds are vetches (Vicia sp.), cleavers (Galium aparine), black nightshade (Solanum nigrum), black medick (Medicago lupulina), spurge (Euphorbia peplus) and cow-thistle (Sonchus oleraceus). In the early spring the wild onion (Allium triquetrum) forms large clumps, as do several species of common wood sorrels (Oxalis sp.) These give way to grasses in the summer and autumn.
Within the quarter-acre strip three sets of traps were used, marked A, B and C in Text-fig. 2. Set “A” on the lower level was surrounded by a belt of grass, mostly Bromus cartharticus, which was in turn bordered by a patch of gorse (Ulex europeus) mixed with broom (Cytisus scoparius), this continues as a horseshoe-shaped belt around the lower edge of the gully and butts on to the study area at its upper end. The traps in “B” partly extended into a patch of periwinkle (Vinca major), fennel (Foeniculum vulgare) and vetch, forming a tangled mass two to four feet high inhabited by large numbers of skinks. Part of this area was further overgrown by a tangled growth of honeysuckle (Lonicera japonica) and a shrubby valerian (Kentranthus ruber). Traps “C” were set on a moderate slope which was sparsely covered with short grasses and patches of valerian 2 to 3 feet tall.
The scattered trees and shrubs together with the fennel, periwinkle, valerian and honeysuckle, form a litter layer from 2 to 6 inches thick which in some parts remains moist all the year round, and contains a rich source of arthropod food for the skinks. There is no running or standing water in the strip. In winter the ground is very damp, with a few small pools of water following rain, but dry conditions generally persist through January to late March or early April. During this latter period the grasses and weeds die down and form in places a thick mat that retains considerable moisture close to the ground surface.
Almost two-thirds of the skinks caught within the study area and all skinks caught elsewhere were caught by hand. Active searching accompanied by turning or lifting of rocks, bricks and any other readily movable objects within the collecting areas exposed skinks which could then be taken by hand. This method was generally more effective when temperatures were sufficiently low to slow down the movement of the animals.
Two traps of the pitfall type were tested. The first of these, a wide-mouth glass preserving jar sunk in the ground so that the top of the jar was flush with the surface, was unsuccessful, probably due to poor siting. Few captures occurred even when the trap was baited with rotting fruit to attract flies. This type was subsequently abandoned. A serious disadvantage of this trap was the tendency to fill with water in wet weather, a problem overcome with the second type of trap adopted, which consisted of a six-inch length of galvanised iron downpipe, 3 inches in diameter, buried as before with its upper lip flush with the surface of the ground. The lower open end allowed water to quickly drain away, and an inch or two of soil filled the bottom of the trap. This soil was soon colonised by a variety of amphipods, isopods and insects, providing an abundant food supply for trapped skinks. Skinks were observed on more than one occasion to examine the interior of the trap, stretching out and looking down into the bottom, before dropping down to the soil beneath.
Both types of trap were covered with a slab of rock or brick supported above the trap lip so as to leave ample room for a skink to enter. A serial number painted on the inside of each trap was used in recording the location of capture of each lizard.
The lizards were marked by clipping the toes in various combinations. Generally no more than three toes were clipped with a maximum of two toes on any one foot. The toes were removed close to the second joint with a pair of fine-pointed scissors. Any toes lost through natural causes were incorporated as conveniently as possible into the marking system. In no case were the toes found to regenerate. The method proved to be very satisfactory; the only difficulty experienced occurred in cases of toes lost through natural causes subsequent to marking. These were often plainly apparent as the marked toes were cut at a constant point and those lost naturally rarely coincided.
The marking of each skink was carried out in the field immediately upon capture or removal from a trap. The trap number, or the point of capture together with any other relevant details, was recorded at the same time. All skinks were then carried in cages to the laboratory for weighing and measuring.
The weight, together with a series of measurements for each lizard, was taken in the laboratory. All measurements were made in millimetres to the nearest 0.5 of a millimetre, and recorded on individual index cards. Each lizard was laid in the supine position and held at the mid-body point with the fingers of both hands. The skink was then gently stretched out by stroking towards the head and tail. This process was repeated for up to three or four minutes if necessary, until the well known state of false hypnosis shown in many species of lizards was induced. Juveniles can be quieted in a shorter time than adults. The small size of L. zelandica rendered this method necessary. The method gave consistently good results.
Each lizard was weighed on a laboratory scale, to the nearest tenth of a gram. Some difference between weights recorded for the one lizard at short intervals may have been due to the presence or absence of food in the skink's alimentary tract. In most cases, however, each animal was held in captivity for 24 hours without food before weighing.
At every opportunity skinks were collected from localities other than the study area selected. Some of these captured were kept in terraria, where their behaviour was observed. Most were preserved and subsequently used for data on variation, the seasonal cycles of the gonads, and the gastrointestinal contents.
Seasonal Cycle of Reproduction
Seventy-eight specimens of Leiolopisma zelandica were collected from the Wellington area, including the Kelburn, Brooklyn, York Bay, Island Bay and Somes Island districts, all adjacent to Wellington City, as well as Pukerua Bay, on the west coast of the North Island, eighteen miles north of Wellington City. The state of development of the gonads of these lizards suggests a well defined gonadal cycle. A few specimens of Leiolopisma aeneum collected from Pukerua Bay showed some differences in the gonadal cycle from that of L. zelandica.
For the greater part of the year there is little difference in the external appearance of males and females, though from November until early February, females carrying young may be recognised by the distended abdomen, and adult males 55.0 mm or more from snout to vent can sometimes be distinguished by a relatively larger head. Males of L. zelandica do not assume an early spring breeding colouration which allows the sex of some other species of skinks to be determined. Moreover, the method whereby males can be induced to evert their hemipenes through pressure exerted at the base of the tail close behind the cloaca, is not reliable in adults of this species, and gives no results in juveniles. Thus no reliable method of sexing live individuals of Leiolopisma zelandica is known, and the sex of adults cannot always be decided even in the breeding season.
The following account of the reproductive cycle of L. zelandica is based on the preserved collection of 78 specimens mentioned above. Because of the difficulty of sexing these specimens externally, the ratio of males to females was not known until they were dissected, when it was found to be one to two. The number of males was not adequate for a full analysis of the reproductive cycle, and there has been no opportunity to obtain further material for all seasons.
Seasonal changes taking place in the gross morphology of the ovaries and oviducts have been studied from 52 specimens of immature and mature Leiolopisma zelandica. In addition 13 specimens of L. aeneum from Pukerua Bay were examined for comparison.
The female reproductive organs consist of equally well developed right and left ovaries and paired oviducts which open separately into the cloaca. The ovaries are elongate oval bodies lying posteriorly and dorsally in the body cavity. The completely transparent ovarian epithelium permits the individual ova to be seen. Each ovary is suspended by a mesovarium midway along the oviduct. The right oviduct is 5.0 mm or so longer than the left, so that the right ovary lies more anteriorly than the left.
In a sub-adult female (less than 50.0 mm in snout-vent length) the ovaries are small, 3.0 mm to 4.0 mm in overall length, with a cluster of pale whitish ova each less than 0.75 mm in diameter. Adult lizards collected during a non-breeding period (i.e., February to March) show six to fourteen whitish opaque ova in each ovary, varying in diameter from 0.1 to 2.5 mm.
L. zelandica has one breeding season in each year; but the ovary contains ova of graduated sizes. From February to April in any one adult ovary there are usually two to three large ova (1.5 mm to 2.5 mm in diameter) at the same stage of development, two or three ova 0.75 mm to 1.0 mm in diameter and seven to eight ova less than 0.75 mm. From April until October large developing ova reaching
6.5 mm in diameter at the end of the period are found within the ovaries. Development of these ova takes place during the hibernation period from early April to the beginning of September, continuing in the early spring until ovulation takes place in the first weeks of October.
Following the rupture of each follicle at ovulation a pale corpus luteum develops within the ovary of L. zelandica and persists until parturition takes place some twelve weeks later. Counts of the corpora lutea present have been used in this study to determine the number of ova released by each ovary in L. zelandica.
The presence of a corpus luteum in reptiles has been recognised since Strahl (1892) described the corpus luteum in Lacerta agilis. Weekes (1934) reviews the early work and describes the corpus luteum in a number of oviparous and viviparous reptiles, including Lygosoma (Leiolopisma) weeksae and Lygosoma (Leiolopisma) entrecasteauxt as well as three other scincid lizards. In the viviparous lizards examined by Weekes the corpus luteum persists for approximately three and a-half months, degeneration beginning at about the end of the second month of pregnancy. By the time of birth of the young, the degeneration has spread through all the luteal tissue, which disappears two weeks after the birth of the young. Boyd (1940), Dutta (1944) and Miller (1948) further established that well developed corpora lutea are formed in several other families of lizards.
The average mass of the ovum at ovulation is 0.10 gm and the average mass of the newly born young 0.26 gm. It follows, then, that more than half the total weight of the fully developed young must be derived from materials transported across the oviduct wall. Thus some form of placentation exists in L. zelandica and the species is truly viviparous, the ova being retained in the oviducts as is the case in all other New Zealand lizards.
Placentation is known to occur elsewhere in the family Scincidae, and Weekes (1935) in a review of placentation among reptiles records two types of placentation within the genus Leiolopisma. The placentation of five Australian members of the genus has been examined: Lygosoma (Leiolopisma) pretiosum, L. (L.) ocellatum, and L. (L.) metallicum (Weekes, 1930). These have a simple type of placentation whereas Lygosoma (Leiolopisma) entrecasteauxi (Harrison and Weekes, 1925) and L. (L.) weeksae (Weekes, 1929) have an extremely specialised placenta. The nature of the placentation in L. zelandica has not yet been examined.
The mature oviducts are superficially pleated externally, folded and flattened against the dorsal body wall. The right oviduct, 18.0 mm to 22.0 mm long, is 4.0 mm or 5.0 mm longer than the left. In immature females the oviducts are folded for the first third of their length, and the remaining portion is a flat ribbon-like band of semi-opaque tissue 1.0 mm to 2.0 mm wide (Text-fig. 3). The gravid oviduct is greatly distended and appears as though chambered. The oviducts of mature females are generally folded and pleated throughout their entire length, especially following parturition, but do not show the distinct “incubatory chambers” which persist in some other lizards.
The first two newly-born young of the 1954–55 breeding season were caught within the study area on January 20, 1955. No more were captured for four days, despite prolonged and careful searching. Then 16 newly-born lizards were taken on January 25 and 26, ranging in size from 24.5 mm to 28.0 mm snout-vent length. The newly-born lizards grow rapidly, and as the first two lizards caught on January 20 were 28.0 mm and 29.5 mm from snout to vent they may have been born towards the beginning of January. A large female weighing 5.2 gm before parturition gave birth to six young from 0.26 to 0.28 gm in weight and averaging 24.9 mm in snout-vent length. Both size and weight appear to be fairly constant for newly-born young. Twenty-two young lizards were caught during the following ten weeks, and by comparing their size with the known rate of growth it could easily be seen that none could have been born later than the middle of February. By the end of February all lizards captured were above 30.0 mm from snout to vent.
When copulation takes place amongst the adults, presumably in October, the young of the year have reached 35.0 mm to 40.0 mm and the ovaries of five such young females examined were about 1.0 mm long, each with a number of small, white opaque follicles less than 0.75 mm in diameter.
The ovarian follicles gradually increase in size, reaching a maximum of 2.0 mm in diameter at the commencement of the lizard's second hibernation when it is 16 months old and 50.0 mm in snout-vent length. The ova enlarge rapidly during the lizard's second hibernation and early spring, continuing to grow for six months until ovulation occurs in early October, when the young female is about 21 months old.
Of the lizards examined, the smallest containing fully mature ova within the ovaries was 54.0 mm from snout to vent. The gestation period is 12 to 13 weeks, and so the females give birth to their first young at the end of their second year.
Text-fig. 3 illustrates the seasonal changes in the external appearance of the ovary following and preceding ovulation. The collapsed follicles are visible immediately after ovulation as large white flat oval sacs, each with a medium longitudinal scar. However, a week or so after ovulation the collapsed follicles become smaller, compact and disc-like, 2.0 to 3.0 mm in diameter, and slightly yellow as the corpus luteum forms within the follicular cavity. The scar on the follicle becomes less obvious being seen as a discontinuity in the general texture of the luteal mass. The corpora lutea persist until parturition occurs, some regression taking place as the diameter diminishes to average 1.5 mm (range 1.0 to 1.75 mm) during December and January. Regression following parturition is rapid, for save for one female with corpora lutea 1.5 mm in diameter which was killed immediately after giving birth to six young, no non-gravid females showed traces of corpora lutea.
The ovaries are at their minimal mass from just after ovulation until after parturition, this being the gestational period when the average weight of the ovary is 2.0 to 4.0 mm. From October until March the resting ovary shows no great change of mass, and contains 2 to 3 corpora lutea 1.5 to 3.0 mm in diameter, 2 to 5 ova approximately 1.5 to 2.5 mm in diameter and seven to eight smaller ova less than 0.75 mm in diameter. In March the larger ova, generally two or three but up to five in an ovary, begin to enlarge, becoming more turgid and a deeper cream colour than the other ova. As the deposition of yolk proceeds the ova become 4.0 to 5.0 mm in diameter by late June (the middle of the hibernation period), the ovaries weighing between 49.0 and 115.0 mgm at this time. By early October, when ovulation occurs the individual ova have reached 5.0 to 6.5 mm in diameter. The weight of a mature ovum is from 75 to 115 milligrams, and the ovary may weigh more than 200 milligrams, depending upon the number of mature ova that it contains. The seasonal changes in the mass of the ovaries based on 44 mature or maturing lizards is shown in Text-fig. 4; the small figure alongside each point plotted indicates the size group to which the lizard belongs. Some correlation can be seen between the size of the lizard and the absolute mass of the ovaries, there being a general tendency for larger lizards to have heavier ovaries. The commonly used index “mass of ovaries as a percentage of body weight” has not been used here as the varying amounts of tail loss and regeneration in the specimens examined does not allow reliable comparisons to be made upon such a basis.
Table II shows the number of ovulations that occurred (as evidenced by corpora lutea within the ovaries), or the number of maturing ova, in 32 individuals. The total number of mature ova produced by any one lizard varies from two to eight, and the number is the sum of an even or uneven number of ova from each ovary. In twenty animals the same number of ova were produced by each ovary.
Twenty-three of the twenty-six lizards had either 2 or 3 mature ova in each ovary. Thus the potential total number of ovulations was 4, 5 or 6 in over 80 per cent of the lizards examined, eleven having 4 ova, six with 5 ova, and nine
Text-fig. 3.—1–6—Seasonal changes in the external appearance of the left ovary of Leiolopisma zelandica from a series of adult females. 1, October ovary, shortly after ovulation, showing corpora lutea; 2, February ovary prior to parturition, corpora lutea persistent; 3, March ovary; 4, April ovary; 5, June-July ovary; 6, September ovary, preovulatory. 7. Gravid adult female, 60.0 mm from snout to vent, dissected to show 7 ova within the oviducts. 8. Immature ovary and oviduct of a sub-adult female 52.0 mm in snout-vent length, April. 9. Left ovary and oviduct of adult female, June. 10. Left oviduct of an adult female 61.0 mm long in October containing 3 ova, just after ovulation. Three collapsed follicles are present in the ovary. 11. Oviduct and left ovary of an adult female immediately after parturition, February. Abbrev.: O, ovarian follicles; CL, corpora lutea; AL, alimentary tract; OV, oviduct; K, kidney.
Text-fig. 4.—Records of the ovary weight as an average for both ovaries for 45 specimens of Leiolopisma zelandica. The small figure alongside each record indicates the size-group to which the lizard belongs, as follows: 1. 21.0–25.9 mm in snout-vent length. 2. 26.0–30.9 mm in snout-vent length. 3. 31.0–35.9 mm in snout-vent length. 4. 36.0–40.9 mm in snout-vent length. 5. 41.0–45.9 mm in snout-vent length. 6. 46.0–50.9 mm in snout-vent length. 7. 51.0–55.9 mm in snout-vent length. 8. 56.0–60.9 mm in snout-vent length. 9.61.0 mm and above in snout-vent length.
|Total Number of Mature Ova.||Number of Lizards.||Distribution of Mature Ova or Corpora Lutea Between Ovaries.|
|Left Ovary.||Right Ovary.||Number of Lizards.|
with 6 ova. From the middle of October to January, the season of birth, with only one exception all females examined that were 54.0 mm or more from snout to vent, were gravid. Gestation therefore is about three months, and does not appear to vary appreciably. As another set of follicles begins to enlarge two or three months after parturition and are ready to rupture six months later, each mature female is able to bear young each year. The above data are summarised in Text-fig. 6, where they are shown in relationship to that of the male cycle.
It is usual for the ova in each ovary to pass into the oviduct on the corresponding side. However, one female was collected which had three ova in each oviduct with two corpora lutea in the left ovary and four in the right. Another lizard was found to have three collapsed follicles in each ovary and two ova in the left oviduct and four in the right. In both cases it can be concluded that an ovum had made a transabdominal passage to reach the oviduct. Weekes (1927) records a specimen of Lygosoma (Hinulia) quoyi with a damaged oviduct in which all of the ova from one side passed to the opposite oviduct. The instances described for Leiolopisma zelandica show the transfer from one side to the other of only one of a number of ova released by the ovary concerned. This may indicate that the ova are released into the body cavity to pass into the oviduct rather than that the funnel actively clasps the ovum in the ovary.
Not all of the ova released develop within the oviducts; in three of the eight gravid females collected fewer ova were found within the oviducts than would be expected from the number of collapsed follicles present in the ovaries. Two lizards had one less ovum in each oviduct than the number of corpora lutea in the corresponding ovaries. One large adult female had 4 and 5 corpora lutea in the right and left ovaries respectively, 3 ova in the right oviduct with well developed embryos, and 5 ova in the left oviduct, but only three of these containing embryos. In two of these cases the number of ovulations at 7 and 9 were higher than is usual. No atiesia of ova within the ovaries was seen; apparently all the mature ova are ovulated.
On passing into the oviducts the ova become elongate, 6.5 to 9.5 mm long and 5.0 to 7.5 mm wide, and lie close to one another in the oviduct, which is expanded but forms a continuous chamber rather than a series of pouches. The right oviduct is still longer than the left. In eight gravid females the left oviducts contained a total of 19 ova and the right oviducts 24. Fully formed embryos unpigmented except for the eyes were found in mid-December, with the surrounding yolk approximately equal in mass to the developing embryo. A gravid female killed in mid-January contained five full-term embryos in all respects no different from newly-born young, accompanied by little or no yolk.
Two lizards were found to have retained within the oviducts embryos that had been arrested in their development through some unknown cause. One of these, a female collected on March 14, 1954, and examined after preservation, had within the otherwise empty oviduct a badly preserved mass 6.0 mm long containing an embryo, the whole forming a single pouch-like expansion of the closely investing oviduct. The second lizard, captured on October 19, 1954, had each oviduct distended by three recently ovulated ova. A vesicle on the right oviduct was connected to it by a narrow neck of tissue. The vesicle contained a well formed embryo, flattened into a concave disc and unaccompanied by yolk. The vesicle was pressed by the right oviduct against the dorsal wall of the body cavity. In this position it had not impeded the passage of the recent ova. Both of these embryos were obviously retained from a previous breeding season.
During gestation the inguinal fat bodies lying posteriorly in the body cavity central to the kidneys and oviducts and lateral to the rectum and bladder undergo reduction in size. The fat bodies of females at the beginning of hibernation in April are discrete and leaf-shaped, 7.0 to 13.0 mm long, 4.0 to 6.0 mm wide and 1.0 to 2.0 mm thick, pale yellow, semi-translucent, and of an oily nature due to
the large number of small oil globules they contain. At the end of hibernation the fat bodies are not obviously reduced in size, being still firm, uniform in thickness, well defined in outline, and persisting unchanged until ovulation. In gravid females the fat bodies become diffuse and thin, forming a discontinuous sheet of the usual general outline and dimensions but the oil distributed in small patches or elongate nodules. Female lizards two weeks before, or after, parturition either lacked fat bodies entirely or showed only a trace of fat within the associated connective tissue.
Sixteen specimens of Leiolopisma aeneum (Girard) obtained on various dates from Pukerua Bay, Wellington, show considerable differences in the reproductive pattern from that of L. zelandica. Twelve specimens of L. aeneum contained maturing ova in the ovaries or ova in the oviducts, distributed as follows:
Eight lizards had a single large ovum in each ovary or oviduct.
Two showed a single large ovum in the right ovary and two ova in the left.
One had two mature ova in the right ovary and none in the left.
One lizard collected on September 22, 1955, had one ovum in the right oviduct and one mature ovum in the left ovary.
In three other specimens also taken on September 22, ovulation had already taken place. Thus in L. aeneum generally one ovum matures in each ovary, and ovulation occurs at least two weeks earlier than in L. zelandica. L. aeneum is a smaller skink than L. zelandica, inhabiting a few restricted coastal regions and islands adjacent to Wellington. The adults rarely exceed 55.0 mm from snout to vent, as against L. zelandica, which reaches a maximum size in the Wellington district of about 64.0 mm. A female L. aeneum 45.0 mm in snout-vent length
Text-fig. 5.—Records of the testes weight as an average for both testes for 26 specimens of Leiolopisma zelandica and 6 specimens of Leiolopsima aeneum. The black circles indicate that sperm was present in the epididymis of the individual concerned. The small figure alongside each record refers each lizard to its size-group as follows:—1. 21.0–25.9 mm in snout-vent length 2. 26.0–30.9 mm in snout-vent length. 3. 31.0–35.9 mm in snout-vent length. 4. 36.0–40.9 mm in snout-vent length. 5. 41.0–45.9 mm in snout-vent length. 6. 46.0–50.9 mm in snout-vent length. 7. 51.0–55.9 mm in snout-vent length. 8. 56.0–60.9 mm in snout-vent length. 9. 61.0 mm and above in snout-vent length.
collected in April had a single large ovum 2.0 mm in diameter in each ovary, indicating that the females mature at a smaller body size than those of L. zelandica.
Twenty-six male Leiolopisma zelandica and six male Leiolopisma aeneum were examined, ranging in size from 25.4 mm to 62.0 mm. Each animal was killed immediately after capture. The testes were measured and the general appearance of each testis, epididymis and vas deferens noted. The testes were then excised and weighed separately. In order to determine the presence or absence of sperm, a portion of the left epididymis was teased apart, stained lightly with aqueous methyl green for two minutes, mounted in water and pressed beneath a cover-slip to spread the material in a thin layer. Sperm could readily be seen in this preparation.
The testes of Leiolopisma are like those of most lizards, being paired oval white bodies suspended on either side of the body cavity by the mesorchia, the right testis lying more anteriorly than the left. The winter testis of adult males captured in June or July is from 3.5 mm to 4.5 mm long, and 1.90 mm to 2.75 mm wide, weighing 2.0 to 8.0 milligrams, and when fresh is pale, wrinkled and flaccid. The epididymis is dorso-lateral to the testis and appears as a compact body 3.5 mm to 4.5 mm long and 1.5 to 2.0 mm wide. Each vas deferens passes back across the mid-ventral surface of the kidney to the cloaca, to open separately close to the urinary duct. In preserved specimens the testis has a yellowish-brown tinge, the epididymis appearing as a snowy-white structure in strong contrast to the black-pigmented peritoneum.
A moderately developed epididymis permitted ready recognition of two juveniles 26.0 mm and 35.0 mm from snout to vent, as males, even though their testes were no different in appearance from the ovaries of immature females; but usually the sex of lizards below 35.0 mm cannot be decided even by dissection, since there is
little difference in the appearance of the male and female gonads and ducts until towards the end of the juvenile males' first hibernation.
The smallest lizard with sperm in the epididymis, collected on July 21, 1954, and 45.5 mm in snout-vent length, was by estimate at least 18 months old. Two other lizards 49.0 mm collected in October, and 46.5 mm collected in November, were not mature. In general, males were at least 51.0 mm from snout to vent before sperm was found in the epididymis. This size is attained towards the end of their second summer before hibernation, when the skinks are by estimate 16 to 17 months old and as no growth occurs in this period the probable time of maturity is on emergence from hibernation when the skinks are 20 to 21 months old.
The adult winter testes range in size from 3.5 mm to 4.5 mm long, 1.9 mm to 2.75 mm wide and 2.0 to 8.0 mgm in weight. The testes of adult animals in the summer months are from 4.0 to 5.5 mm long, 2.2 to 4.25 mm wide and 8.0 to 32.0 mgm in weight. Thus the testes of adult lizards are less in weight and size, particularly in diameter, during the winter months.
Text-fig. 5 shows the testis weight as an average for both testes, for twenty-five specimens of Leiolopisma zelandica and six Leiolopisma aeneum, plotted against the time of the year. The testes are at their minimal mass during June and July, the middle of the hibernation period. Collections during September and October contained too few males to establish the exact time of increase in testis mass, though skinks collected in September and October showed that there is some increase in testis size and weight. From January to April the testes averaged greater in weight than testes from lizards collected during the hibernation period.
From January to June the males 51.0 mm or more in snout-vent length contained sperm within the epididymis. In July, two large adult males contained no sperm, one only a small amount, and three other lizards abundant sperm. Only six lizards, four of which were sub-adult, were examined in September, October and November, and none of these showed sperm in the epididymis, although the testes were of mature size. Text-fig. 6 gives the overall picture of the male cycle, and its relation to the female cycle.
Copulation would be expected to occur at the time of, or shortly after, sperm production in the males and about the same time as ovulation in the females. Ovulation takes place in the first weeks of October, a time which apparently does not coincide with the presence of sperm in the epididymis of the males, as shown in the graph (Text-fig. 5), though it does appear to coincide with a rapid increase in testis size. Copulation has not been observed in the field, and the only copulation seen occurred between two lizards held in the laboratory on March 28, 1955. The attitudes assumed in copulation are shown in Text-fig. 7. The copulating lizards were two of eight that had been caught some 48 hours previously, and placed in a glass trough prior to release, and the copulation may have been a displacement activity, the product of the close confinement and the abnormal conditions to which the lizards were subjected. However, as both this observed copulation and the presence of abundant sperm in all males at this time could indicate that copulation takes place in the late summer, smears were taken from the vents and oviducts of the females collected for the next five months, from early April to late August. No sperm was found in any of these smears, but as they were made from preserved material the results cannot be regarded as conclusive.
From the above data it can be seen that examination of male lizards does not allow the time of copulation to be precisely determined. Either copulation occurs about the time of ovulation in the females, thereby coinciding with the rapid seasonal increase in testis mass, or else copulation precedes hibernation and females retain sperm until ovulation in the following spring, as do certain salamanders (Stebbins, 1954).
Female skinks are not known to retain sperm for lengthy periods before ovulation. Studie on Eumeces fasciatus by Fitch (1954) and Eumeces septentrionalis
by Breckenridge (1943) have shown that copulation occurs after the animals emerge from hibernation and that the eggs are laid only a few weeks later. In both of these lizards there is a definite enlargement of the testes in the early spring, similar to that in L. zelandica. However, no data is available on sperm production in Eumeces and the significance of sperm within the epididymis in relation to the time of copulation is not yet determined.
No growth study of any member of the genus Leiolopisma has yet appeared. However, the growth rates of several species of the scincid genus Eumeces have been determined by the use of two main methods. Taylor (1936) briefly discusses growth in the genus Eumeces on the basis of a fairly large series of museum specimens which he sorted into age-size groups, concluding that members of the genus required as long as nine or ten years to attain adult size. Breckenridge (1943) marked all the individuals in a small colony of Eumeces septentrionalis in Minnesota, and Rodgers and Memmler (1943) made large “year round” collections of Eumeces skiltonianus near Berkeley, California. Both of these skinks were found to reach mature size (65.0 mm) at the end of their second year, E. septentrionalis breeding in the following spring and E. skiltonianus at the end of its third year. Fitch (1954) showed that Eumeces fasciatus reaches small adult size in the growing season following its first hibernation and becomes sexually mature when about 20 months old, and that Taylor's age groups were artificial, for there is much overlapping in size, even between the two more or less distinct age groups present.
Although E. septentrionalis, E. skiltonianus and E. fasciatus belong to separate groups within the genus Eumeces, the two former species resemble one another in their growth pattern and in the time they take to reach maturity, but E. fasciatus is notably different in its more rapid growth and the shorter time it takes to reach sexual maturity.
Leiolopisma zelandica resembles Eumeces fasciatus in its rapid rate of growth and early maturity.
In the present study, growth has been investigated by measuring and then releasing as many young and adults as possible, some of which were recaptured to provide growth records. The marking programme was carried out in the study area close to the University, from the end of May, 1954, until September, 1955, during which time two hundred and twenty-two lizards were marked and measured.
The period of the study included only one breeding season, and the majority of the animals marked were of adult size. Thus it has not been possible to follow the growth of an individual lizard from birth to adult size; however, sufficient information has been obtained from the 61 lizards recovered at least once to indicate the general pattern of growth. Table III presents the number of captures and recaptures, the greater number of lizards being taken in the summer period between the hibernations of 1954 and 1955.
|No. of Animals Marked and Measured.||No. of Lizards.||Total No. Of Lizards Recaptured.||Total No. Of Captures.|
|Caught Once.||Caught 2 Times.||Caught 3 Times.||Caught 4 Times.||Caught 5 Times.||Caught 6 Times.|
As indicated in a previous section, parturition in 1955 took place from early January to early February, the majority of the young being born in the last week of January Some variation in the period probably exists between different years and in any one year within separate parts of the reptile's range.
A series of 19 newly-born young captured over three days at the peak of the parturition period averaged 0.276 gm weight (range 0.18 to 0.40 gm) and 27.6 mm long from snout to vent (range 24.5 mm to 29.0 mm). Six young born to one female in captivity averaged 0.265 gm (range 0.18 to 0.40 gm) and 24.8 mm long from snout to vent (range 24.5 mm to 25.0 mm).
The most rapid growth occurs in the weeks immediately after birth; for example, a lizard (No. 118, Table IV) captured soon after birth when 25.0 mm long, showed an average gam of 0.17 mm and 0.007 gm per day over a period of 50 days. Two other juveniles (Nos. 87 and 95, Table IV) averaged 0.15 mm and 0.14 mm per day respectively in snout-vent growth, and No. 87 gained 0.007 gm per day in weight, but No. 95 showed no weight increment. Another juvenile (No. 93, Table IV) marked soon after birth at a snout-vent length of 25.5 mm was recaptured 243 days later in the following spring when 37 5 mm in length and three and a-half times its former weight. The slight increase in length of only 2.0 mm for this lizard, when compared with No. 87, which was first marked on the same day at the same snout-vent length but recaptured after only 68 days at a length of 35 5 mm, indicates that the initial rapid growth does not extend over the hibernation period. One lizard (No. 79, Table IV) was 29.5 mm in snout-vent length when captured on January 29, 1955, and on recapture 35 days later it was 38 5 mm. It can be assumed that this lizard was of average size when born, and from this it can be estimated that the time of birth was probably in the first week of January, so that its size on entering hibernation would be at least 45.0 mm. The size range of juveniles entering their first hibernation is from 30.0 to 45.0 mm, with most lizards between 35.0 and 40.0 mm.
|Animal No.||Date 1955.||Snout-vent length in mm.||Tail length in mm.||Weight in grams.||Remarks.|
|118||Feb. 2||25.0||28.0||0.4||8.5 mm snout-vent length; 5.0 + mm tail length; 75% weight increase in 50 days. Capture points 45ft apart.|
|Mar. 24||33.5||33.0 (tip lost)||0.7|
|87||Jan. 26||25.5||15.5 + (stump)||0.3||Showing rapid growth of lizard and marked as newly-born young, only a few days old. 10.0 mm snout-vent length; 17.0 mm tail, weight increase × 2⅔ in 68 days. Captures 30ft apart.|
|Apr. 6||35.5||25.5 + 7.0||0.8|
|93||Jan. 26||25.5||29.0||0.29||Captures 50ft apart. 12.0 mm snout-vent length; 13.0 mm tail growth; weight increase × 3⅓. Compared with No. 87 in text. Marked only a few days after birth.|
|Sep. 29||37.5||42.0 + (tip lost)||0.99|
|95||Jan. 27||26.0||31.0||0.3||2.5 mm increase in snout-vent and tail length in 18 days. No appreciable weight increase. Captures 10ft apart. Newly-born skink.|
|79||Jan. 21||29.5||34.0||0.46||Points of capture 10ft apart. Rapid growth of very young lizard caught and marked soon after birth. Discussed fully in text. First captured 2 weeks after birth.|
|Animal No.||Date.||Snout-vent length in mm.||Tail length in mm.||Weight in grams.||Remarks.|
|196||1955||25 mm snout-vent growth, no weight increase in 54 days. Slow growth of yearling during hibernation period.|
|12||1954||Little growth during hibernation period. Slight weight increase. Tip of tail lost on revovery. But very large amount of regenration for young animal. Capture sites 3 feet apart.|
|Jun. 22||38.0||7.5 + 22.0||0.8|
|Aug. 18||38.0||7.5 + 21.0||1.0|
|127||1955||Points of capture within a 6 feet radius. 4.0 mm snout-vent growth; 7.0 mm tail growth; 15% weight increase; in 65 days to April 6. No growth over hibernation period.|
|78||1955||Loss of weight shown; animal carrying young on January 20. Taper of tail almost perfect, regeneration difficult to assess. Captures within a 12 feet radius.|
|Jan. 20||58.0||54.5 + 6.0||4.0|
|Mar. 28||59.0||58.0 + 3.5||3.0|
|Jul. 18||59.0||58.0 + 3.5||3.2|
|Oct. 22||59.0||58.0 + 3.5||3.5|
|6||1954||All captures within a 3 feet radius. Note slow growth of tail during hibernation period then rapid increase in rate. Regeneration 7 mm in 70 days (Aug. 2-Nov. 9).|
|May. 24||58.0||25.0 + 6.0||3.4|
|Aug. 2||58.0||26.0 + 5.0||3.3|
|Aug. 17||58.0||26.0 + 5.5||3.2|
|Nov. 9||58.5||26.0 + 12.5||3.4|
|135||1955||Captures within a 6 feet radius. No growth during hibernation period.|
|Mar. 3||60.0||57.0 + 7.0||4.6|
|Mar. 7||60.0||57.0 + 7.0||4.4|
|Mar. 22||60.0||57.0 + 7.0||4.0|
|Mar. 25||60.0||57.0 + 7.0||-|
|Aug. 29||60.0||57.5 + 7.0||3.3|
|140||1955||Capture points the same each case.|
|Mar. 7||62.0||16.0 + 28.0||3.9|
|Mar. 22||62.0||16.0 + 28.0||3.6|
|206||1955||Capture points 19 feet apart.|
|Jun. 16||63.0||14.0 + 27.0||4.0|
|Nov. 1||63.0||14.0 + 27.0||4.0|
|Animal No.||Date||Snout-vent Length in mm.||Tail length in mm.||Weight in grams.||Remarks.|
|37||1954||Approx. 9 months old when first caught. 14.0 mm snout-vent length; 21.0 mm tail growth; 64.6% weight increase; in 165 days from Sep. 22, 1954 to Mar. 7, 1955. Captures within a 10 feet radius.|
|31||1954||Lizard probably about 20 months old at first capture. 7.5 mm snout-vent growth, 80% weight increase; in 224 days. Recaptured 30 feet from point of first capture.|
|Sep. 2||48.5||33.5 + 17.0||1.9|
|Apr. 4||56.0||38.0 + 10.5 (tip lost)||3.4|
|127||1955||First captured when about 1 year old. 4.0 mm snout-vent growth; 7.0 tail length; 15% weight increase; in 65 days (to April 6, 1955). Capture points within a 6 feet radius.|
|41||1954||7.0 mm tail growth; 4.0 mm snout-vent length; 40% weight increase; in 35 days. Rapid growth following first hibernation. Captures within a 6 feet radius. Lizard about 9 months old when first captured.|
|Oct. 19||36.0||16.5 + 14.5||0.7|
|Nov. 23||40.0||17.5 + 20.5||1.0|
|50||1954||Rapid growth in early summer 2.0 mm snout-vent length; 3.5 mm tail length; growth in 23 days. Capture points 7 feet apart. About 9 months old.|
|Anima No.||Date||Snout-vent length in mm.||Tail length in mm.||Weight in grams.||Remarks.|
|59||1954||4.5 mm snout-vent growth, 8.0 mm tail growth in 133 days. No growth during hibernation.|
|103||1955||Probably 2 years old at first capture 4.0 mm snout-vent length, 2.5 mm tail length in 44 days (Jan. 26-Mar. 11, 1955). Captures within a 5 feet radius.|
|Jan. 26||50.5||9.5 + 25.0||2.0|
|Mar. 11||54.5||10.0 + 27.0||2.4|
|Nov. 12||57.0||11.0 + 27.0||3.25|
|67||1954||5.0 mm snout-vent growth, 6.5 mm tail growth in 98 days. Captures within a 10 feet radius.|
|Nov. 29||52.0||13.0 + 29.0||3.7|
|Mar. 7||57.0||14.5 + 34.0||3.6|
|Mar. 22||57.0||14.5 + 34.0||3.3|
|22||1954||All captures within a 6 feet radius. Period of at least 15 days before tail regenerated. 11.0 mm tail regeneration in 104 days (Aug. 17-Nov. 29).|
|Oct. 19||55.5||11.0 + 3.0||2.9|
|Nov. 1||55.5||11.0 + 7.0||2.7|
|Nov. 12||55.5||11.0 + 9.5||3.0|
|Nov. 29||57.0||11.0 + 11.0||3.3|
|39||1954||22.0 mm tail regeneration; 5.0 mm snout-vent length; 30% weight increase; in 97 days. Recaptured within 2 feet original capture site.|
|Oct. 17||55.0||9.0 + 9.0||2.7|
|Feb. 1||60.0||9.0 + 31.5||3.5|
|51||1954||7.0 mm snout-vent length; 20.0 mm tail growth; 25% weight increase in 104 days; summer growth.|
|Feb. 14||62.0||9.0 + 21.0||3.0|
|54||1954||5.0 mm snout-vent growth; 20% weight increase. Points of capture 7 feet apart.|
|Nov. 15||56.0||12.0 + 33.0||3.0|
|Aug. 29||61.0||12.0 + 20.0 (tip lost)||3.7|
|14||1954||All captures within an 8 feet radius. 20.0 mm tail regeneration in 259 days (June 21, 1954 to March 7, 1955).|
|June 21||58.0||36.0 (no reg)||3.3|
|Nov. 23||58.0||36.0 + 5.5||3.9|
|Mar. 7||60.0||37.5 + 20.0||4.5|
|17||1954||Captures within a radius of 10 feet. 3.0 mm snout-vent growth; 4.0 mm tail growth; in 312 days. No growth during hibernation period. Tail fully regenerated.|
|July 7||60.0||6.5 + 28.0||3.2|
|Mar. 15||63.0||5.5 + 33.0||3.5|
|Mar. 28||63.0||5.5 + 33.0||3.1|
|Oct. 21||63.0||5.5 + 33.0||3.4|
|Nov. 12||63.0||5.5 + 33.0||3.3|
|8||1954||3.0 mm body growth; 2.0 mm tail growth; 0.3 gm increase in weight; in 376 days. Captures in successive hibernation periods, only 2 feet apart.|
|May 27||62.0||26.0 + 26.5||4.7|
|July 7||65.0||27.5 + 27.0||5.0|
|30||1954||Gravid female, 1.7 gm increase in weight in 97 days, abdomen width increased from 11.0 mm to 15.5 mm in same period. Captures 3 feet apart.|
|Aug. 18||66.0||24.0 + 27.0||5.0|
|Nov. 23||68.0||23.5 + 28.5||6.7|
Text-fig. 9.—Records of growth in all the individual skinks marked and subsequently recaptured one or more times. The figure alongside certain of the records refers to the detailed recapture data in Tables IV (Juveniles), VI (Sub-adults) and VII (Adults).
There is little or no growth of the lizards during hibernation as shown from measurements of a small number found while hibernating (Text-fig. 8; Table V). This period is not included in the graphs showing the growth rates of marked animals subsequently recovered. The length of the hibernation period omitted is based on the observed activity of the lizards within the study area.
The young lizards reach adult size 50.0 mm in snout-vent length during their second summer following their first hibernation. Very few young lizards were caught and only one recovery after a long term was made (No. 37, Table VI). This lizard averaged 0.085 mm per day increase in snout-vent length and 0.009 gm per day increase in weight for 165 days between hibernations, and reached an adult size of 51.0 mm when about 16 months old. Three other short-term recoveries (Nos. 41, 50 and 127, Table VI) showed similar trends in growth, respectively averaging 0.11, 0.087 and 0.062 mm per days increase in snout-vent length.
It is not clear whether the small number of sub-adult lizards captured was due to the few young surviving from a previous unrecorded breeding season, or to their more secretive habits. The lizards reach adult size over the brief span of 3 to 4 months in the first half of their second season of growth, and in these, the months of October, November and December, the vigorous plant growth of early spring provides much concealing cover which does not allow the young lizards to be readily caught.
The different growth rates of both the juvenile and sub-adult lizards leads to the loss of identity of the age-size groups as some of the lizards approach small adult size. Overlapping in size may occur between lizards 14 to 16 months old and individuals with retarded growth a year older. A rapidly growing juvenile (such as No. 79, Table IV) could attain a length of 45.0 mm at the end of its first season of growth, and be at least 55.0 mm long by the end of its second season of growth, when two years old. The group of lizards marked when about 55.0 mm in snout-vent length (Nos. 22, 51, 39, 67 and 54, Table VII) could include one or more lizards that reached large sub-adult size in their first season of growth. Despite the possible overlap these are in the main lizards in their third season of growth from 19½ months to 27 months old. The lizards above 55.0 mm in snout-vent length, that show a much slower rate of growth (Nos. 14, 17, 8, Table VII) are in their fourth season of growth, being 31½ to 39 months of age.
The average rates of growth of lizards for successive size increments has been calculated from all the recoveries shown in the graph (Text-fig. 9), and are presented in Table VIII. As the size group 55.0 to 59.9 mm includes lizards in both their third and fourth (and perhaps fifth) season of growth, two different rates of growth are evident. The averages for this size class have been calculated separately and as for other size classes the hibernation period of four and two-thirds months has been subtracted where necessary from the time elapsed between captures. The growth rates for each size class include those of some individuals that were recorded as growing through one or more size classes between captures which may produce inaccuracies in the average rates recorded.
The average growth rates are graphed in Text-fig. 10, together with a small number of individual recoveries which illustrate typical growth trends in relation to the calculated average. In order to obtain the time in months that it takes for a lizard to grow through a particular size class, the average monthly increment in millimetres for the lizards of a particular class was divided into the total increment within the size class. The periods of growth and hibernation with the sizes at different ages are included to provide a general picture of the growth of L. zelandica.
|Size Group (snout-vent length) in mm.||Average Growth per Month in mm.||No. of Skinks in Sample.||Total Growth Recorded in Sample in Months.||Remarks.|
|25.0–39.9||4.11||4||9⅔||Juveniles before first hibernation.|
|35.0–44.9||3.30||3||4¼||Sub-adult lizards in second growth season.|
|45.0–49.9||1.53||4||7½||Sub-adult lizards in second growth season.|
|50.0–54.9||1.50||10||20||Small adult lizards to 22 months of age.|
|55.0–59.9||0.76||15||36½||Overall average for size class.|
|1.33||7||17½||Adults 22–26 months in third growth season.|
|0.24||8||19||Adults in at least fourth growth season.|
|60 & above||0.28||11||41||Large adults of indeterminate age.|
Text-fig. 10.—The average growth rate for successive size increments in Leiolopisma zelandica based upon the records of the skinks marked and subsequently recaptured. The unbroken lines accompanied by a number are individual recoveries (Tables IV, VI and VII) included to show typical growth trends in relation to the calculated averages (Table VIII).
Some lizards may fail to reach adult and breeding maturity by the time of emergence from their second hibernation. No direct evidence of this was obtained; the growth trend of one short term recovery (No. 50, Table VI) indicates that this lizard may have been no more than 45.0 mm long on entering its second hibernation. Individuals differ in their rate of growth, some continuing to grow rapidly until above average adult size and others ceasing rapid growth when below average adult size. The time of birth is critical in that it decides the maximum size that the
lizard reaches before entering its first hibernation. Similarly an extended autumm, allowing a longer first growth season, would show itself in later years by the presence of larger than average adults within any one age class which could only be separated from older lizards by their faster rate of growth.
The age-size classes of the population of L. zelandica studied (as represented by the average growth rates of those lizards recaptured) are thus not distinct from one another. The only readily identifiable group are lizards in their first year less than 46.0 mm in snout-vent length. A typical lizard (based upon the average rates of growth for successive size increments) attains 35.0 mm in snout-vent length at the commencement of its first hibernation when two and a-half months old. Growth ceases during hibernation and in its second growing season the juvenile reaches 45.0 mm at the end of one year and 50.0 mm at fourteen and a-half months of age, at which size the lizard enters hibernation for the second time. In the third growth season the lizard reaches 55.0 mm in snout-vent length when about twenty-two months old. Above 55.0 mm two rates of growth are apparent, the faster growing lizards being adults in their third season of growth, and the slower growing animals adults four or more years of age. The average rates of growth for lizards of these two ages which mix within a single size group are calculated separately. A few individuals may reach 60.0 mm in length by their 26th month, but in general the lizards do not exceed 60.0 mm until they are at least 34 months of age. The lizards mature sexually after their second hibernation, when above 50.0 mm in snout-vent length and at about 20 months of age.
The weights of all the lizards handled from the study area, either once or as recoveries, are plotted against their snout-vent lengths in Text-fig. 11. The relation
between body weight and size is by no means uniform, as the varying amounts of tail loss and regeneration affect the bodyweight by as much as 18 per cent. Gravid females may be 30 per cent. above their normal weight just before parturition, the weight increase being in direct proportion to the number of young carried.
The average weight of the young at birth is 0.25 gm (range 0.18 to 0.40 gm), and the juvenile lizards enter hibernation three months later when 35.0 to 40.0 mm long, averaging 0.94 gm (range 0.65 to 1.65 gm), increasing in weight by three and one-third times in the first season of growth.
In the second growth season the young lizards increase in length to 45.0 to 50.0 mm, weighing on the average 2.28 gm (range 1.95 to 3.5 gm), thus multiplying their weight by two and two-fifths times. Thereafter the increase in weight is no more than 20 per cent. in any one season of growth. Lizards less than 55.0 mm in snout-vent length rarely exceed 3.5 gm, and those between 55.0 mm and 60.0 mm long 4.5 gm. The maximum weight recorded was 6.6 gm for a very large gravid female 65.6 mm long, just prior to parturition.
Growth and Regeneration of the Tail
The relative length of the tail varies considerably even among lizards that have never lost their tails. Also during the course of growth of the young lizards to sub-adult size the relative proportion of the tail changes. Text-fig. 12 shows the relative tail length (as a percentage of snout-vent length) in skinks of different size groups with undamaged tails.
At birth (20.0 mm to 25.0 mm from snout to vent) the tail length averaged 110.5 per cent. of the snout-vent length. In larger young from 31.0 mm to 40.0 mm the tail continues to grow more rapidly than the body, averaging as much as 126 per cent., which is greater than the average length of either smaller or larger lizards. The average tail length of lizards 45.0 mm to 55.0 mm in snout-vent length was less, averaging 123 per cent., and a small number of lizards 56.0 mm to 60.0 mm averaged 113.0 per cent. No sexual dimorphism was evident in this feature from the data available.
Of some 274 lizards handled in the field or laboratory 179, or 65.8 per cent, had recently broken or regenerated tails. A freshly broken lizard's tail loses almost no blood; only a few small drops are seen to ooze from the irregular surface of the exposed concave muscle masses of the tail stump. The detached portion with its protruding muscle masses may continue to writhe for several minutes. At room temperature of 17.6° C. a newly broken section of tail 21.0 mm long lashed violently from side to side for 95 seconds. Rolling and twitching continued with decreasing magnitude for a further 85 seconds, then voluntary movements ceased. At the end of eight and a-half minutes contractions and brief twitches could still be induced by touching the tail, and severe stimulation elicited slight twitches at the end of thirty minutes.
A scab forms across the newly-broken stump within a few hours; the surrounding scales which project slightly beyond the point of the break fold inwards to form a smoothly rounded stump. Since no lizards were seen with infected tail breaks the conclusion that some prophylactic mechanism operates can be drawn. When the scab is lost the healed surface of the break is covered with a convex, smooth black skin, finely granular in texture (Text-fig. 14). No further growth occurs for a week or two, then regenerative growth proceeds rapidly, the sharply tapering new growth being of less diameter than the old tail at the point of break. A dull black skin of silky texture with no signs of scales, covers the regenerating tail whose tip is bluntly rounded Scale formation does not occur until the length of the regenerated portion approaches two-thirds of its ultimate length, which is generally less than that of the old tail. Such scale formation is seen as a series of concentric ridges arising at the old overlapping scales and gradually spreading towards the tip of the tail. The colour and form of the regenerated tail do not match those of the old tail. The new scales are coloured a dull orange dissimilar to any other
colour on the skink's body and instead of two scale rows in the mid-dorsal and mid-ventral region of the tail, single large scales form equal in width to two ordinary scales. In a fully regenerated tail the new scalation merges evenly into the old, often obscuring the original break which can be detected only by its dull orange colour and different scale pattern.
Large adult lizards may possess tails with three or more sections each set off from the other by a slightly different angle of taper, as the regenerated portion is also capable of regrowth when broken. Breaks in the tail occur at the mid-point of a single vertebra and not intervertebrally, a cartilaginous rod replacing the vertebrae in the regenerated portion
Fitch (1954) points out that the rate of growth of the regenerated tail depends upon the age, condition and activity of the individual together with the position of the actual break. If a young lizard loses its tail early in life it is possible for the length of the regenerated tail to be greater than that of the old tail. The regenerated tail of adult lizards rarely attains the length of the original; the absolute length reached depends upon the position of the break. The closer the break is to the vent the longer the length of the regenerated tail, but the likelihood of the regenerated tail reaching the length of the old tail becomes less. The proportion of original and regenerated tails of 179 lizards are plotted in Text-fig. 15. Lizards which have a stump of the old tail equivalent to 20 per cent of their snout-vent length at the maximum regenerate a length equal to 65 per cent of their snout-
Text-fig. 12.—Diagram showing relative tail length (as a percentage of snout-vent length) in skinks of different size-groups that retained their original tails unbroken. The relative increase in tail length in the early stages of growth is apparent, the trend being reversed before adult size is reached. The mean, standard error, standard deviation and range for each size-group is shown.
vent length; the total tail length at 85 per cent of snout-vent length is considerably less than that of unregenerated tails which in adult lizards average 113 to 123 per cent of snout-vent length (Text-fig. 12).
In skinks with the original tail equal to 40 per cent of the snout-vent length, the fully regenerated tail may reach 107 per cent of the snout-vent length; and in those with stumps 60 per cent of the snout-vent length the completely regenerated tail may reach 113 per cent of the snout-vent length. Lizards which have a length
Text-fig. 13.—Diagram showing the relative length of the tail stump (as a percentage of the snout-vent length) in skinks of different size-groups that have at some stage lost their tails. There is an apparent trend for larger (and older) lizards to have less of their original tail. The mean, standard error, standard deviation, and range is shown for each size-group.
of old tail equal to 80 per cent or more of their snout-vent length may regenerate enough tail length to restore the tail to its former length (Text-fig. 15). The skinks measured included many with incompletely regenerated tails, which accounts for the wide range of variation shown. The completely random scatter of the proportions of the original tail shows that there is no tendency for the tail to break at a particular point. Breaks occur at any point along the tail length, being unusual only close to the vent; generally a length of old tail at least equal to 10 per cent of the lizard's snout-vent length remains. Larger and older lizards lose a greater portion of the original tail probably due to successive tail breaks, although the complicating factor of increase in torso length with age may enhance this effect (Text-fig. 13).
The growth rate of the regenerating tail is rapid following the initial healing period, which lasts two or three weeks. The fastest rate of regeneration recorded amongst 20 individuals (Text-fig. 16) was 1.13 mm per week in a lizard whose tail regenerated 21.5 mm in 132 days The record marked “A” on the graph is the most complete one obtained from a lizard with a recently broken tail The tail stump of this lizard was freshly healed at the first capture, the amounts of regeneration for 5 successive captures were 15th day after first capture, no regeneration;
Text-fig. 14.—The successive stages of tail regeneration in Leiolopisma zelandica. (1–7 are drawn to the same scale) 1. Stump of a freshly broken tail showing protruding muscle masses and the scales overlapping the actual point of break. 2. The exposed surface of the tail portion lost in 1. 3. The healed surface of the tail stump about 2. weeks after loss The overlapping scales have folded inwards over the wound. 4. First stage of tail regeneration about 2. weeks after regeneration commenced. 5. Regenerated portion before scale formation commences. 6. Incipient scale formation. 7. Regenerated tail with fully formed scales of a different shape to those of the original tail. 8. Fully regenerated tail. The discontinuity shown at the mid-point of the regenerated portion is produced by secondary regeneration of a once regenerated tail.
Text-fig. 15.—Relative lengths of original and regenerated portions of tails in skinks which have had their tails broken and regenerated; for each individual the length of the regenerated portion and the original portion is separately expressed as a percentage of the snout-vent length.
47th day 3.0 mm; 58th day 7.0 mm; 69th day 9.5 mm and 86 days after the first capture 11.0 mm of tail was regenerated. The changing rate of growth is followed by a period of rapid growth which gradually slows as the regenerated tail approaches its final length. Skinks with a substantial portion of tail already regenerated showed only a slow increase in tail length of as little as 1 mm in 7 months.
The tail is lost as the result of mechanical damage of some description. No skink of the hundreds handled during the course of the study dropped its tail when handled with normal care. A blow, a sudden jerk or pinching of the tail, is necessary before a length is detached. Leiolopisma zelandica can be lifted and even restrained by the tail, and as long as there are no sudden pulls the tail will not be dropped. When the skink is attempting to escape in the field there may be a condition set up in the animal that facilitates tail loss if the lizard is grasped by the tail. The tail is used as a storage organ for fat, and the usually round tail becomes emaciated and square in cross-section in lizards deprived of their normal food supply. One lizard that lost a previously unregenerated tail close to the base at capture suffered a decrease in total weight of 18 per cent. Thus the loss of the tail may involve the loss of a considerable amount of stored fat.
During the study period from March, 1954, to October, 1955, moulting was first observed in a lizard captured on October 19, 1954, which shed its skin in a laboratory cage. The slough was completed in 24 hours from the onset, the newly exposed epidermis having an iridescent sheen which still persisted when the animal was released two days later. Five other lizards captured in the following five weeks showed varying degrees of slough, the last being taken on November 29, 1954. Others captured in this period had the typical sheen of new skin, signifying a recent moult.
In all the lizards observed shedding followed a fairly well defined pattern. The scales of the ventral surface of the head and body, the flanks and the dorsal surface of the neck extending back to above the forelimbs, are the first to be lost. The epidermis flakes off in the form of transparent scales corresponding to the underlying osteoderms, scales being lost in irregular patches, singly or in sheets of several dozen that cling loosely together. Next the epidermis of the ventral surface of the tail, the upper parts of the limbs and the dorsal surface of the body are shed. Then the scales covering the head shields and the lower parts of the limbs are lost, so completing the slough In contrast to the rest of the animal the epidermis of the manus and pes is cast off in the form of a complete “glove” which rolls back on itself until it is sufficiently loose to be rubbed off in the course of normal movement. The sloughed-off epidermis frequently remains only as an anklet or wristlet after the rest of the moult has been completed.
Moulting appears to be restricted to about a six-week period extending from mid-October to the end of November. One skink captured on January 18, 1955, had the sheen usually associated with a recent moult, and the period may not be as brief as indicated above. As the process is rapid in a healthy skink, and can be completed in 24 hours, it is not surprising that it was observed on relatively few occasions.
Feeding Habits and Food
In this study skinks have been seen feeding on only a few occasions in the field as their secretive habits prevent ready observation. L. zelandica is diurnal and vision possibly plays a considerable part in the detection and selection of suitable food. The gastrointestinal content of the skinks examined consisted mainly of terrestrial arthropods.
Both juvenile and adult skinks select actively moving prey in preference to stationary food animals even though the moving insect may be the more distant. Several times both in the field and the laboratory skinks have been seen to investigate suitable food which was finally rejected when the lizard failed to stimulate the food animal into activity.
The gastrointestinal contents of 68 specimens of L. zelandica were examined. Two-thirds of the specimens were collected at points within a radius of ten miles from the study area, with the exception of 18 specimens from Pukerua Bay and four from Stephens Island. All the specimens were killed immediately after capture; however, four from York Bay that were received some days after capture had empty stomachs.
The specimens represent seven localities each with a slightly different range of ecological conditions and microhabitats. Accordingly the analysis of the stomach contents of the groups from each place are presented separately in Table IX to bring out any local differences in food habits. Seventeen specimens of L. aeneum from Pukerua Bay were also examined, and some appreciable differences are apparent between the food of this species and that of L. zelandica.
As each skink was dissected the entire alimentary tract was removed, placed under water in a watch glass, and the stomach and intestinal contents examined separately. Complete insects were rarely found, some parts being lost or digested more rapidly than others and the remainder present as a felted mass of legs, abdomen segments, fragments of thorax chitin and head capsules. Soft bodied animals such as coleopteran and lepidopteran larvae were not found below the stomach. The prosoma of spiders, chitinous insect appendages, head capsules and wings, persisted unchanged down to and in the rectum.
Faecal pellets were not found in the field, and no attempt has been made to examine scat material. The typical pellet is a small elongate cylindrical mass 2.0 to 3.0 mm long by 1.5 mm wide, almost invariably capped at one end with a chalky mass of uric acid.
A summary of the material identified from all the specimens examined is presented in Table IX. The individual animals composing the food were not identified beyond ordinal rank.
Of the 68 specimens of L. zelandica examined, 12 (17.6 per cent) had completely empty alimentary tracts. None of these skinks was taken in hibernation, and all the specimens of L. zelandica captured in the winter months contained some food. None of the 17 specimens of L. aeneum was captured whilst in hibernation, and 5 contained no food remains.
The average number of food items per lizard for 9 specimens of L. zelandica taken in the hibernation period was 3.77, contrasted with an average of 5.03 items per lizard for 61 lizards captured in the summer months. Even though the rates of digestion are probably slower in the winter months, the presence of some food in the stomachs of lizards collected in June and July indicates that intermittent feeding may occur during hibernation, which agrees with the finding given later that hibernation is often interrupted and not continuous.
A total of 297 food items, an average of 5.47 items per lizard, were collected from L. zelandica alone, and of these, 217 were insects, 80 arachnids and 75 terrestrial amphipods or isopods. The prey ranged in size from small mites less than 1.0 mm long to a single large lepidopteran larva 21.5 mm long by 4.5 mm which entirely filled the distended stomach of one individual. Normally the food was less diverse in its size range, generally consisting of food items 1.0 mm to 6.0 mm long. Perhaps the most unusual food was from an adult female 53.0 mm long collected on the seashore of Island Bay, Wellington, on March 1, 1954, which contained 63 mosquito larvae, 2.0 mm long. This skink was captured within 30 yards of a number of brackish splash zone pools a few feet above high tide level which contained
|Food Organisms||Orthoptera||Hemiptera||Coleoptera||Lepidoptera||Diptera||Hymenoptera||Thysanura||Pseudoscorpionidea||Dermaptera||Amphipoda||Isopoda||Araneida||Acarina||Unidentified Arthropod Material||Mollusca||Nematoda||Plant Material||Males||Females||Number of Lizards|
|Pukerua Bay No of Organisms||1||16||4||4||4||1||-||1||-||7||12||10||21||-||-||24||-||8||10||18|
|Frequency - No Lizards||1||6||5||4||4||1||-||1||-||3||4||6||5||5||-||4||6|
|Brooklyn Wellington Organisms||4||11||8||2L||6||-||-||-||3||8||14||14||-||-||1||13||-||7||13||20|
|Kelburn Wellington Organisms||1||18||10||1L||-||4||-||-||-||9||5||2||4||-||-||15||-||5||7||12|
|Island Bay Wellington Organisms||7||17||2L||2L||67||10||-||-||-||1||9||10||10||-||-||9||-||-||7||7|
|Stephens Island Organisms||1||4||11||1||7||2||1||-||-||1||5||6||2||-||-||11||-||1||3||4|
|Somes Id Wellington Organisms||-||2||-||-||1||1||-||-||-||4||-||1||-||-||-||2||-||2||1||3|
|York Bay Wellington Organisms||-||-||-||-||-||-||-||-||-||-||-||-||-||-||-||32||-||-||4||4|
|Totals Food Organisms||14||68||37||7L||85||18||1||1||3||30||45||43||37||-||1||106||-||23||45||60|
|Frequency - No Lizards||10||24||18||18||14||10||1||1||1||17||19||27||9||20||1||24||11|
|Frequency as a percentage of total lizard sample||14 9||35 3||26.5||26 5||20 6||14.9||1 5||1 5||1 5||25.0||27 9||39 7||13.2||29 8||1 5||35 3||16 5|
|Frequency - No Lizards||-||7||-||-||2||2||-||-||-||2||2||1||6||3||-||-||-||7||10||17|
|Frequency as a percentage of total lizard sample||-||41 2||-||-||11 8||11 8||-||-||-||11 8||11 8||5 9||34.5||17 7||-||-||-|
many thousands of larvae of the mosquito Opifex huttoni which breeds in salt water. The number of Diptera recorded in Table IX is thus abnormally high and is not typical of the food of the lizard.
Aside from small particles of soil, other non-animal inclusions were mainly plant material such as small pieces of leaves, grass stems and seeds. The seeds may have been taken as food, for in all cases they were too large to have been swallowed accidentally and could hardly have accompanied other food. Two skinks from Pukerua Bay contained single large dark-brown seeds 4.5 × 2.0 mm and 3.5 × 1.75 mm, of plants of the family Polygonaceae, and two other lizards from the same locality each contained another large unidentified seed 6.0 × 3.0 mm and 4.0 × 2.5 mm All the seeds were hard and undigested There was no material of any description in the gastrointestinal contents that indicated cannibalism or the eating of slough.
The largest variety of food found in any one animal was recorded from an adult female L zelandica 60.0 mm long, collected from Stephens Island on December 18, 1954 The detailed list is as follows, the figure in parentheses being the largest dimension of the food item in millimetres stomach, 2 dipteran flies (5.0), 1 adult beetle (4.5), 1 beetle larva (3.0), 1 hemipteran (4.0), 1 small piece vegetable matter (3.0), 4 large wood lice (5.0, 4.0, 4.0, 3.0), 1 thysanuran (6.0); intestine, 3 Hemiptera (7.5), 3 beetle heads, 1 woodlouse, 3 heads Diptera, 1 moth (3.5); rectum, 3 Coleoptera (elytra only), 2 Hymenoptera (5.0), and the heads of 1 orthopteran insect and 1 dipteran fly. This lizard was unusual in that 8 different orders were represented in its food, when generally arthropods belonging to 1 to 4 different orders comprised the food of any one animal.
Many of the Hemiptera, Lepidoptera, Diptera and Arachnida appeared to be of the kinds usually found amongst herbaceous vegetation. The terrestrial amphipods and isopods which form a major portion of the skink's food (in bulk as well as numbers) are plentiful in dank and humid surroundings beneath rotting vegetation, logs and stones. The range of food found in the gastrointestinal contents of the species indicates that L. zelandica forages in many parts of its environment, preying upon the arthropodan fauna of all levels from that found in its shelters to that of the herbaceous vegetation of its home range. The most important food organisms of the species in order of the frequency of occurrence are: spiders and hemipterans, followed by isopods, coleopterans, lepidopterans and amphipods in almost equal frequency.
The food of Leiolopisma aeneum is similar in some respects, hemipteran insects and spiders constituting the bulk of the food items found However, there are two marked contrasts in the absence of any coleoptera or lepidoptera, which may either point to differences in the feeding habits of L. aeneum or reflect differences in the microfauna of its environment.
Slightly more than one-third of the specimens of L. zelandica examined were infected with a parasitic nematode identified as Pharyngodon sp. (order Oxyuroidea). This short stout nematode about 4.0 mm long was found in the rectum. No nematodes were obtained from Leiolopisma aeneum.
Only two previous studies of the movements of skinks have been made, these being by Goin and Goin (1951) on Eumeces laticeps and Fitch (1954) on Eumeces fasciatus Fitch reports that Goin and Goin found that E. laticeps has a well defined territory, each adult excluding other adults from its home territory but tolerating young, and each lizard centering its activity around some convenient shelter that forms a home base. In contrast E. fasciatus is not territorial in its behaviour and has no regular home base; tending to limit its activities to a small area, wandering little. Studies by Newmann and Patterson (1909), Fitch (1940) and Stebbins and Robertson (1946) on three different species of the iguanid genus
Sceloporus have shown that the individuals of the species tend to keep to well defined areas, with territorial behaviour well developed. Numerous other studies on reptiles, particularly turtles and snakes, have demonstrated the presence of home ranges generally much larger than those of lizards.
The individuals of L. zelandica wander little, centering their activities about a small area, even smaller than Fitch records for E. fasciatus. Territoriality does not appear to be developed to any extent, and individual home ranges may overlap with the home ranges of one or several other lizards.
The information on the movements of L. zelandica has been gathered from the capture of marked individuals. No detailed records over a specific time are available for a single individual skink and the pattern of the movements in relationship to time and their possible causes are unknown. A skink may have wandered considerable distances between captures, including the very periphery of its home range, and recaptures must represent only a portion of the lizards' total range. Direct observations on the movements of L. zelandica are precluded by the nature of the environment which obscures the skink during its moves. The available evidence points to naturally delimited routes of approach and retreat from certain areas such as basking places.
The position of each skink, marked or unmarked at capture, was recorded in relation to a named reference point, there being no lack of suitably distinct landmarks within at the most ten feet of the capture site. The skinks were released at precisely the same point after weighing and measuring in the laboratory. The elapsed time between successive captures varied from one day to 14 months, and although recoveries less than one month apart were rarely of value in determining growth rates, the short term recoveries were often the most useful for assessing home ranges.
Fitch (1954) assumes “.… that any two successive captures of the same individual separated by a substantial time interval will be distributed at random to each other within the area to which the animal's activities are confined. The varied techniques of capture by hand and with different types of traps would help to secure random distribution of the capture sites. If the home range were covered uniformly by the animal in the course of its activities, any two random capture sites would be on the average separated by a distance equal to half the home range diameter. If the animal tends to concentrate its activities in the central part of the home range as seems to be the case the capture sites will be correspondingly closer together”. The same basis as that used by Fitch is assumed in assessing the significance of the distances between captures Two-thirds of the lizards captured were taken by hand, which assures the random nature of capture site distribution. The average distance between captures for 21 lizards (excluding juveniles in their first year) captured only twice, was 6 feet (range 0 to 23 feet), which indicates that the size of the home ranges of L. zelandica in the study area is relatively small.
The greatest distance between successive captures was 50 feet, for a juvenile marked 8 months previously, and the least movement in terms of time was that of a lizard taken by trap or hand 5 times in 6 months at the same place. The average distance between captures for 45 adults in 75 moves was 5.9 feet (range 0–18 feet), and for 8 sub-adult lizards 9.4 feet in 13 moves (range 0–32 feet). Six juveniles in their first year were recaptured an average distance of 24.5 feet from the marking site (range 6–50 feet). The longest moves recorded occurred in the juvenile lizards in their first few months preceding hibernation.
All the juveniles recovered in their first year were recaptured only once after marking, and so their home ranges cannot be delimited. Two juvenile skinks were recaptured within 6 feet of their first capture after 24 and 30 days, whereas the three longest moves by juveniles (Nos 87, 118 and 93, Table IV) of 30, 45 and 50 feet were after periods of 68, 50 and 243 days respectively. The first pair of juveniles may have already established a range when first caught and others moved in search of suitable home ranges during the period between captures.
The dispersal phase occurs in the juveniles, for not only were their moves the longest ones recorded, but they were almost invariably captured whilst moving across the surface carpet of dry grass far from cover in the form of stone or concrete slabs. The behaviour of the young is quite distinct in this respect, for the adult skinks are rarely found far from immediate cover.
The short distances between the captures of sub-adult and adult lizards indicates that these lizards have regular home ranges.
Table X gives the distances between successive recoveries for all adults, which are divided into three groups with regard to the time of marking and recapture;
|Adults: No. of Captures, Sexes not separated.||Average Distance in Feet Between Point of Capture and Extremes for All Moves.||Average Maximum Distance in Feet Between Points of Capture.||No of Skinks in Sample.||Time of Year.|
|Individuals captured just twice||4⅓ (0–9)||4⅓||9||Marked and recaptured in summer between hibernations.|
|Captured 3 times||6⅓ (0–19)||10||7|
|Captured 4 or more times||2⅘ (0–10)||5⅔||5|
|Individuals captured just twice||93/4 (8–18)||93/4||4||Long term recoveries, including both hibernation and summer period.|
|Captured 3 times||6¼ (0–18)||10||8|
|Captured 4 or more times||7½ (0–18)||16||3|
|Individuals captured just twice||1¼ (0–5)||1||7||Lizards marked and recovered within a single hibernation period.|
|Captured 3 times||2½ (0–5)||5||1|
|Captured 4 or more times||2½ (0–5)||5||1|
the lizards marked and recovered in a single summer between hibernations; the long term recoveries including both the summer and part of the hibernation period; and those found two or more times whilst in hibernation.
The calculated averages are based upon recoveries representing individual home ranges, for no definite changes of range were recorded. The average home range diameter of 18 feet obtained for all adults (with the exception of those in hibernation) is calculated from the average maximum distance between captures. The actual area of such a home range would be approximately 15 square yards.
The home ranges of lizards caught a sufficient number of times to allow the shape and size of their home ranges to be determined, are given in Text-fig. 17, 18 and 19. The letters enclosed in a circle on each of these text-figures relates the particular portion of the study area figured to the plan of the whole area (Text-Fig. 2).
The detailed record of each skink whose home range is figured can be found in the preceding section on growth, with the exception of lizards Nos. 59, 74 and
Text-fig.. 18.—Successive capture sites for another group of skinks also on Station B, and recorded in the same period as those shown in Text-Fig. 19.
159 which are presented below. The individual records for the home ranges in Text-fig. 19 are not detailed since the majority of these lizards were captured in the same narrow area during hibernation. The sex of the lizards where determined has been indicated on the figures.
Lizard No. 59. Three captures in ten months, on October 24, 1954, on April 5, 1955, 30 feet from the first capture site; trapped once more on September 29 within 10 feet of the first capture site. This lizard shows the largest single home range of any recovered, and was just below adult size when first captured (48.75 mm) and of adult size (53.5 mm) when recaptured for the first time.
Lizard No. 74. Large adult female 62.0 mm long. Taken twice in January in the same trap. Carrying young on January 17, 1955. Parturition occurred within the 10-day period. Trapped twice more in another trap 8 feet distant on March 7, and 22, 1955.
Lizard No. 159. Large adult female 64.0 mm long. Marked just before hibernation on March 10, 1955, recaptured in the same trap on November 15, 1955, and trapped 4 feet away 7 days later.
The size of the adult home range does not vary greatly and no difference in size is apparent between the home ranges of adult males and females. The home ranges of lizards No. 37 and 59 (Text-fig. 17) are larger than the average adult range, the distance between their successive captures being a little more than one and a-half times that of the adults. Both of these lizards were sub-adults when first captured, and were recaptured as adults. Thus the largest single home range recorded was that of a sub-adult lizard, No. 59, which was captured in two successive summers at points 10 feet apart and found hibernating in the intervening winter 25 feet from its nearest other capture. The longest extension of this lizard's home range area was toward the basking area marked in Text-fig. 17 and 18.
The overlapping of the home ranges is well illustrated in Text-fig. 17 and 18. The home ranges shown in these figures were obtained from lizards captured concurrently in the area (Station B, Text-fig. 2) and have been separated to avoid overcomplicating the diagrams.
The shape of a lizard's home range appears to be modified according to the nature of the plant cover and physical features of the environment. Most of the home ranges figured are triangular in outline, which is due in part to the fact that many were based on three different points of capture.
The study area contains many terraced portions separated from each other by concrete walls of varying heights, and moderate grassy slopes. The skinks travel along the natural pathways at the base of these walls, moving vertically up the surface of the walls where their surfaces are sufficiently rough. They follow regular escape routes which are decided by the nature of the terrain, moving directly ahead when disturbed, passing up and then down any obstruction in their path if they cannot escape by any other means. The home range may include two or more levels separated by a wall, usually with a fissure or overhanging mass of vegetation by which the lizard passes from one level to another. Leiolopisma zelandica has been observed to launch itself down and across small gaps up to 10 inches wide even when moving about undisturbed. Tree climbing has not been seen; however, two instances were recorded of a skink climbing amongst the dense heads of fennel (Foeniculum vulgare) between 2 and 3 feet above the ground.
No definite change of range was recorded for any lizard marked and recaptured in the study area, even though it contained the home ranges of a large number of lizards. Any shifts of range may have taken the lizard concerned outside the limits of the study area. Despite frequent searches extending many hundreds of feet outside the study area, no marked skink showing a change of range was found, all the lizards captured being unmarked. Some of the unmarked skinks captured in the study area, especially late in the marking programme, may have entered the area from the surrounding ground.
Skinks shift their ranges through various causes, one at least being interference with the surrounding environment. Twenty-six were captured and marked in one small area (Station A, Text-fig. 2) thirty feet in diameter. The vegetation about the area was cut and trimmed by a party of workmen who burned the resulting plant debris within a few yards of the capture site. Not one of the 26 lizards has since been taken, although a few unmarked lizards were captured within the same general area after several months had elapsed. Station A thus suffered frequent human interference, and the few home ranges recorded in this area (Text-fig. 19) area of lizards which changed cover during hibernation with some moves in the following summer. Very small, well-defined home ranges may be maintained by lizards that are undisturbed. Several skinks never captured have been observed inhabiting the same concrete ledge or brick heap throughout the study. One of these lizards, readily recognisable, has been seen basking on one particular ledge on numerous occasions over an eighteen month period, eluding all attempts at capture by escaping down a crevice only a few inches from its basking place.
Thus individuals of L. zelandica tend to remain within small areas which are their regular home ranges. These ranges are generally about 15 square yards in extent, being modified in size and shape according to the individual and its position in the area. In the study area the abundant plant cover, the concealment available in the form of numerous crevices under concrete walls and slabs, the plentiful food and wide distribution of basking places, allow the skinks to fulfil all their needs within a small area. The home ranges of two or more individuals may overlap. Groups of lizards congregate in the basking places, tolerating each other and showing no signs of territorial behaviour. The home ranges of adult females and males do not apparently differ in size or shape. The sub-adult lizards may have slightly larger home ranges than the adult skinks. The greatest distances between successive captures were those recorded for juvenile skinks in their first year in the dispersal phase that occurs in the few months preceding their first hibernation.
The Wellington district is not subjected to severe winter temperatures, the frosts are infrequent and light, and the ground is never frozen. Consequently L. zelandica is not forced to resort to the deep burrowing into the earth typical of some species of hibernating skinks in the higher latitudes of the northern hemisphere (Breckenridge, 1943). The relatively mild local climate does not induce the complete suspension of activity in all members of the skink population, for skinks whose winter refuges are exposed to the sun on warm winter days may emerge to bask. The study area was inspected at least once every fine day during winter when there was any likelihood of skinks coming out to bask, and the pit-traps were left open throughout the winter of 1955. Lizards were not taken in the traps during the winter months, indicating that most lizards remained in hibernation. However, on July 7, 1955, a warm sunny day, a single skink was seen basking on a concrete ledge sheltered from the prevailing cold southerly wind and close to a heap of damp and decomposing vegetation. When caught as it attempted to seek concealment under a stone protruding from the heap of plant debris, the skink was still warm to the touch. This skink may have sought other shelter on release as it was not retaken in subsequent searches of the area. McCann (1955) records L. zelandica as emerging to bask on warm days during the winter months.
The marking programme was commenced a few months after the beginning of the 1954 hibernation period, and all the skinks captured in the first few months of the marking programme were in hibernation. A solitary lizard was seen basking on August 18, 1954, after a few days of warm weather, which were followed by several days of cold wet weather. Then on August 30, 1954, many lizards were seen basking, the population remaining active for the rest of the spring and the summer. The activity of the population declined once more in the first two weeks
of April, 1955. As only seven more skinks were trapped in September, a particularly wet month, the general emergence from hibernation may have been delayed. Thus the hibernation period is approximately four and a half months long, extending from the middle of April to the end of August.
Cover is so abundant in the study area that no lizard would need to move far in order to find a suitable winter refuge. The few recoveries made during hibernation show that any moves at this time are generally confined to a single piece of cover, although the lizard may move to other shelter if disturbed too often, as several skinks found hibernating on two or more occasions subsequently moved to other resting places. The lack of difference between the size of the home ranges of lizards captured only in the summer months and those marked or recaptured during hibernation and retaken in the summer months indicates that the skinks seek a place to hibernate within their home range areas. Text-fig. 19 shows the movements of a group of skinks captured one or more times during hibernation, and the average distances moved for all skinks captured when in hibernation are included in Table X.
Fitch (1954) points out that the lizards' habitat may be scarcely recognizable from the lizards' point of view when it emerges from hibernation. The changes that take place in the area studied are primarily in the density of the herbaceous vegetation. The dry, low-lying vegetation of late summer and autumn is replaced by a vigorous growth of grasses and weeds, in particular onion-weed (Allium triquetrum) and fennel several feel high. Such growth differences, Fitch maintains, may promote changes of range brought about by the dramatic changes in the microhabitat. None of the skinks captured in successive summers were recorded as changing their range, and the effect of the seasonal changes in the plant cover upon the lizards cannot be assessed.
The relatively mild climate of the Wellington area does not induce the deep hibernation characteristic of skinks found in regions with more severe climates. Food was found in the alimentary tracts of some specimens taken in the middle of the hibernation period, and several skinks whose hibernation sites were more likely to be exposed to the direct warmth of the winter sun were observed basking during this period. Thus hibernation is not always complete in L. zelandica, and certain individuals may emerge to bask and feed in a period when the remainder of the population is comparatively inactive.
Escape Reactions and Predators
Lizards of the family Scincidae are generally secretive, relying on their ability to seek concealment rather than speed or aggressive behaviour to escape their enemies. Leiolopisma zelandica is no less secretive than the other members of the family, and it invariably seeks cover at the slightest danger.
The behaviour of the newly-born lizards renders them more conspicuous than the adults. In the period immediately following parturition in January, the greatest activity occurred in the lizard population. At this time as many as 40 newly-born young were caught when moving across patches of short grass far from the type of cover favoured by the adult. The behaviour of these juveniles is characteristic of animals in the dispersal phase, and probably results in a higher mortality rate amongst the juveniles than the adults. This is borne out in part by the numbers of young found with damaged tails, for 21.9 per cent of the 51 juveniles captured before their first hibernation had broken or regenerated tails. An overall percentage of 65.8 of the 274 lizards captured during the study had broken or regenerated tails.
Leiolopisma zelandica can often be detected by the rustling of leaves as it moves undisturbed beneath the herbaceous vegetation, and the noise may on occasions indicate the skink's position to predators. When disturbed the skink immediately seeks shelter beneath suitable cover, and often the first sign of their presence is a fleeting glimpse of a moving brown form. Once in adequate cover the skink does
not retreat far, and remains close by until the danger has passed, when it resumes its former position. Many times during the study skinks were captured by waiting quietly beside the spot where they were last seen.
Protective colouration aids L. zelandica in its concealment. The drab straw brown of the lizard's upper surface, dark-brown flanks and longitudinal light coloured stripes, blend well with many backgrounds. However, L. zelandica has not been seen to “freeze” in the presence of danger as does Eumeces fasciatus (Fitch, 1954). Leiolopisma zelandica differs from the skinks of the genus Eumeces in that the adults become only slightly darker with age and retain the basic colour pattern of their youth, also the adult males do not assume a conspicuous breeding colouration. The more conspicuous colour phases found in the genus Eumeces are thus not present in L. zelandica which tends to make the latter species less conspicuous to predators.
The natural enemies of L. zelandica are not well known. Wodzicki (1950) in a discussion of the food of the wild cat (Felis domesticus), notes that, “Various species of lizards are favoured by cats …” The extent of the predation by cats on the species was well illustrated towards the beginning of the study when a mass of recent vomit containing the remains of six L. zelandica was found on a path adjacent to the study area. The bodies of these skinks showed numerous small puncture marks probably made by the teeth of a cat, and undoubtedly constituted a single meal.
Oliver (1955) describes the following birds as feeding upon “lizards”: the red billed gull (Larus novaehollandae scopulinus), the morepork (Ninox novaeseelandeae novaeseelandeae), the harrier hawk (Circus approximans), the bush hawk (Falco novaeseelandiae), the kingfisher (Halcyon sancta), the pukeko (Porphyrio melanotus stanleyi) and weka (Gallirallus australis). Each of these birds constitutes a predator only in certain parts of the lizard's range. The kingfisher is probably the most widespread enemy of L. zelandica; Oliver (1955) records Guthrie-Smith as noting that lizards sometimes form the main diet of this bird. Kingfishers were seen in the study area on four occasions, but were not seen taking lizards. A number of introduced birds such as the black backed magpie (Gymnorhina hypoleuca) and the starling (Sturnus vulgaris vulgaris) may feed on lizards, but the habit is not recorded in the literature.
Seventeen species of scincid lizards have been described from the New Zealand region, and with one exception all belong to the genus Leiolopisma. As no other detailed studies have been conducted on the New Zealand Scincidae, few comparisons can be made between species on the basis of the present study.
The number of head plates of L. zelandica was examined and found to be constant except for the upper and lower labials and the nuchals. The number of scales round the mid-body and the number of subdigital lamellae under the 4th toe of the hind-limb were counted in 50 specimens in an effort to test the constancy of specific characters. The ratio snout-forelimb length to axilla-groin length varied from 1.2 to 2.0 (2.0 +) in the 50 specimens of L. zelandica examined. McCann (1955) gives this ratio at 1.0 + to 1.5 based upon the examination of at least 40 specimens. The higher ratio was the product of a slightly larger sample, taken from a single district, whereas McCann's specimens are the equivalent of a number of small samples from the total range of the lizard. The character is in no way critical in the diagnosis of the species and in other respects the measurements and scale counts agree with those given by McCann (1955).
In recent years ecological and life-history studies have been made in North America on several oviparous skinks of the genus Eumeces by Rodgers and Memmler (1943), Breckenridge (1943), and Fitch (1954). As L. zelandica is viviparous its
reproductive pattern shows few similarities with the genus Eumeces. However, L. zelandica resembles at least one of the Eumeces species in its pattern of growth.
Two main differences were found to exist in the reproductive pattern of L. zelandica and L. aeneum. The small sample of L. aeneum examined averaged only two ovulations per female, and L. zelandica was found to give birth to 3 to 5 young each year. L. aeneum is a smaller lizard than L. zelandica, becoming sexually mature at about 45.0 mm in length. It is not clear whether the difference in the number of young is an effect of the smaller size or of genetic and ecological factors. The females of L. aeneum were found to have ovulated two weeks earlier than L. zelandica in 1955.
Fell (1948) recorded three observations of viviparous reproduction in New Zealand skinks assigned by him to the genus Lygosoma. Two specimens of Leiolopisma moco gave birth to single young, one in February and the other in March, 1946, and another skink Lygosoma (Leiolopisma) smithu gave birth to young in March. Fell does not state where the specimens were collected, but if taken south of the 38° S. parallel it was most probably Leiolopisma zelandica. Therefore parturition may not always occur at the same time each year or in successive years, as parturition occurred in the skink population of the study area in January and early February, 1955.
In view of the differences in the number of young recorded within the genus Leiolopisma, the degree of placentation, and the time of parturition, the life history of L. zelandica cannot be held to be completely typical of the rest of the genus in New Zealand.
The gestation period of L. zelandica is at least three months. The only gestation period reported for a viviparous scincid is that of Lygosoma (Hinulis) quoyi which is approximately three months. The iguanid Leiolaemus multiformis multiformis carries its young for 5 to 7 months (Pearson, 1954) and in Xantusia vigilis gestation was found to be for three months. The gestation period in L. zelandica does not seem to be unduly long for a lizard.
Fitch (1954), who studied a large population of Eumeces fasciatus, determined from marked and recaptured individuals that the species reaches adult size and becomes sexually mature when about 20 months old. Similarly, the use of the marking method in this study has shown that L. zelandica also reaches adult size and becomes sexually mature at about the same age as E. fasciatus.
Several methods have been used to study growth in reptiles. Taylor (1936) discussed growth in the genus Eumeces on the basis of a fairly large series of museum specimens which he sorted into age-size groups, deciding that the lizards in the genus required 9 to 10 years to attain adult size. Later Rodgers and Memmler (1943) determined, by collecting large samples during the course of a single year, that Eumeces matured in two years, and Breckenridge (1943) confirmed this by studying a small population of marked animals. Breckenridge also found that skinks held in captivity did not grow as fast as those in the wild.
The age-size groups of L. zelandica (apart from young in their first year) cannot be separated into sub-adult and adult animals except upon the basis of the known growth rate of the individual concerned.
Thus the present study supports the conclusions of Breckenridge (1943) and Fitch (1954) in reaffirming that information derived from the capture-recapture method of studying the growth rates of animals under natural conditions is more reliable than data obtained either from the grouping of apparent age-size classes of a population or from animals reared in captivity.
The new-born young of L. zelandica increase in length by at least 40 per cent and more than double their weight in the first season of growth, and thereafter the rate of growth becomes progressively less. L. zelandica resembles many other species of lizards in its rapid rate of early growth. (Fitch, 1940; Breckenridge, 1943; Fitch, 1954).
Many snakes and turtles have been found to occupy regular home ranges. The home ranges of lizards are less well known, those of the iguanid genus Sceloporus being better understood than any other lizards. Goin and Goin (1951) observed territorial behaviourism in the skink Eumeces laticeps and Fitch (1954) described the movements and home ranges of Eumeces fasciatus finding that defensive territorial behaviour was lacking.
The adults of L. zelandica tend to have small home ranges, but they do not always occupy a set site within the area. The home ranges may overlap and no defensive territorial behaviour is shown. This pattern is similar to that recorded for the skink Eumeces fasciatus by Fitch (1954) and differs from that found in the iguanid genus Sceloporus (Newmann and Patterson, 1909; Fitch, 1940; Stebbins and Robinson, 1946) which occupy specific places in the habitat and show a marked degree of aggressive territorial behaviour.
The new-born young of L. zelandica were found moving in the open more frequently than the adults, and it is not unlikely that predators exact a heavy toll, for very few sub-adult lizards of 9 to 10 months of age were captured in the course of the study. There is the possibility that few young were born in the previous breeding season, but this cannot be demonstrated in the present study. A high incidence of tail loss was found in the young of L. zelandica. Fitch (1954) indicates a similar loss in the young of Eumeces fasciatus and he decided that the mortality rate was high amongst the hatchlings. The few sub-adult lizards captured and the high incidence of tail loss in juveniles of L. zelandica would appear to indicate a high mortality rate amongst new-born individuals. If this is the case, the proportion of the population replaced each year may be slight, particularly in view of the low birth-rate found in the species.
The enemies of lizards in other countries are numerous and include many kinds of snakes, birds, small mammals and even other lizards (Breckenridge, 1943; Stebbins and Robinson, 1946; Lewis, 1951; Fitch, 1940 and 1954). New Zealand has no indigenous snakes, large lizards or predatory mammals, which restricts the lizard predators to a few species of birds and the domestic cat. The effect of a few predators upon the size of skink populations is not known. Nevertheless, decidedly dense populations may be built up in favourable conditions, for 222 individuals were marked within the quarter-acre study area and it is estimated that the population would be at least equivalent to 900 skinks per acre. Fitch (1954) found concentrations of a similar order of density in one particularly favourable habitat of Eumeces fasciatus but generally populations were in the order of 50 to 100 animals per acre. The study-area habitat may not be typical and the optimum conditions present may support a population well above the density as known here.
Summary and Conclusions
1. The common brown skink Leiolopisma zelandica was studied from March, 1954, to October, 1955. The growth, movements and habits of L. zelandica were studied by marking and subsequently recapturing skinks that formed part of a dense population in a small area at Kelburn, Wellington, New Zealand. Skinks were also collected from several other areas in the Wellington district for supplementary data on food and reproduction.
2. L. zelandica is described and tables are given showing the variation in the numbers of certain head plates and body scales based upon an examination of 50 specimens. The number of scales round mid-body, subdigital lamellae, nuchals and upper and lower labials, show slight variation. Other plates are constant. A range of body proportions was found greater than that already described for L. zelandica. The ratio of snout-forelimb against axilla-groin is 1.2 to 2.0. The present status of the species is not affected.
3. The main features of the male and female reproductive cycles of L. zelandica are described from 71 specimens collected over a two-year period. Additional in-
formation derived from 19 specimens of L. aeneum is included. The females and apparently the males also, become sexually mature when about 50.0 mm in snout-vent length and 20 to 21 months of age, following their second hibernation. The females give birth to their first young when two years of age. The males of L. zelandica show no breeding colouration, and the adult males and females (apart from gravid females) cannot readily be distinguished. A seasonal testicular cycle was found to be present in the male, the testes of adults falling to a minimal mass in June and July. The time and duration of testis enlargement was not fully established.
4. Copulation was observed once in the laboratory and is illustrated. Copulation has not been observed in the field and the time that it occurs has not been determined. Leiolopisma zelandica has but one breeding season in each year. The ova develop within the ovaries for 6 months during the winter and spring. Generally 2 or 3 ova develop in each ovary, and all are ovulated in late spring. A corpus luteum forms within the collapsed follicle, persisting until parturition occurs. Gestation requires 12 weeks, and 3 to 5 young are born in midsummer or early autumn. The time of parturition may vary over the range of the species in any one year, and from year to year. Some form of placentation exists in L. zelandica, and the species is truly viviparous. The type of placentation present cannot be determined by reference to that already known to be present in the genus.
5. L. aeneum gives birth to fewer young than L. zelandica. In consequence of this and other differences, the life history of L. zelandica may not be typical of the other members of the genus in New Zealand.
6. The new-born young of L. zelandica average 27 6 mm in snout-vent length, grow rapidly in the late summer, and by the time of their retirement into hibernation they may have increased their weight by two and a-half times and their snout-vent length by approximately 40 per cent. After emergence from hibernation the young continue their rapid growth, and when a year old some may be as large as small adults. In general, however, the young reach small-adult size at the end of their second summer when 15–16 months old, and become sexually mature in the following spring when 20–21 months old. Considerable overlap is found between the age-size classes of sub-adult and adult lizards. The only readily distinguishable size classes are those of young lizards in their first year. Growth continues through-out life. The rate becomes progressively slower in the adults in their third and fourth growth seasons.
7. Most individuals have lost their original tails, and a high percentage of broken tails is found even amongst the young. Two-thirds of all the lizards examined had broken or regenerated tails. After a brief period of healing the tails rapidly regenerate, the regenerated portion bearing different scalation from the original tail. The regenerated tail is rarely as long as the original lost portion.
8. Examination of the gastrointestinal contents of 68 specimens showed that L. zelandica is a predator, feeding almost entirely on small invertebrates. The principal food organisms of the species are, in order of frequency: spiders and hemipterans, with isopods, coleopterans, lepidopterans and amphipods of almost equal occurrence.
9. Slightly more than one-third of the specimens of L. zelandica examined were found to contain a parasitic nematode Pharyngodon sp. (fam. Oxyuroidea) infecting the rectum.
10. The individuals of L. zelandica tend to remain within the small areas which are their regular home ranges. These ranges are generally about 15 square yards, being modified in size and shape according to the individual and its position in the area. In the study area the skinks can fulfil all their needs within a small area. The home ranges of two or more individuals may overlap. Groups of lizards congregate in the basking places, tolerating each other and showing no signs of territorial behaviour. The home ranges of adult females and males do not apparently
differ in size or shape. The sub-adult lizards may have slightly larger home ranges than the adult skinks. The greatest distances (50 feet) between successive captures were those recorded for juvenile skinks in their first growth season. The juveniles form the dispersal phase of the population and establish a home range about the time of their first hibernation.
11. The relatively mild climate of the Wellington area does not induce the deep hibernation characteristic of skinks found in regions with more severe climates. Individual skinks whose hibernation sites are more likely to be exposed to the direct warmth of the sun may emerge to bask and feed. The hibernation period at Kelburn, Wellington, was approximately four and two-thirds months long in 1954 and 1955.
12. Moulting is restricted to a six-week period extending from mid-October to the end of November. The scales are shed in irregularly sized patches and the whole process may be completed in 24 hours.
13. The population in the study area consists of at least 200 animals, and is probably equivalent to a population of 900 skinks per acre. This dense population indicates that particularly favourable conditions for L. zelandica are found within the study area.
14. The natural enemies of L. zelandica are not well known. However, the red billed gull, the morepork, the harrier hawk, the bush hawk, pukeko and weka have been recorded as feeding upon lizards, and these birds take L. zelandica in only certain parts of its range. The most widespread enemies of L. zelandica are the kingfisher (Halcyon sancta) and the cat (Felis domesticus).
I wish to thank all those who have helped in many ways during the course of this study, particularly Professor L. R. Richardson, for his encouragement, advice and willing assistance throughout the whole period. I am also indebted to Mr. W. H. Dawbin and Mr. J. A. F. Garrick for their useful suggestions and help, and to Dr. R. V. Brunsdon for occasional assistance in the field.
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—— 1954. Life History and Ecology of the Five-lined Skink, Eumeces fasciatus. Univ. Kansas Mus. Nat. Hist. Misc. Publ. 8 (1): 1–156.
*Girard, C. S., 1857. Proc. Acad. Philad.: p. 196.
*Goin, O. B., and Goin, C. J., 1951. Notes on the Natural History of the Lizard, Eumeces laticeps in Northern Florida. J. Florida Acad. Sci. 14: 29–33.
Gray, J. E., 1843. in Dieffenbach, E., Travels in New Zealand, Vol. 2. Fauna of New Zealand. John Murray, London.
Harrison, L. and Weekes, H. C., 1925. On the Occurrence of Placentation in the Scincid Lizard Lygosoma (Leiolopisma) entrecasteuxi. Proc. Linn. Soc. N. S. W. 50 (4): 470–486.
Lewis, T. H., 1951. The Biology of Leiolopisma laterale (Say). Amer. Mid. Nat. 45 (1): 232–240.
McCann, C., 1955. The Lizards of New Zealand. Gekkonidae and Scincidae. Dominion Museum Bull. No. 17: 1–127.
[Footnote] *Not available during the course of this study
Miller, M. R., 1948. The Seasonal Histological Changes Occurring in the Ovary, Corpus Luteum, and Testis of the Viviparous Lizard Xantusia vigilis. Univ. Cal. Publ. Zool. 47 (8): 197–224.
Newmann, H. H., and Patterson, J. T., 1909. Field Studies of the Behaviour of the Lizard, Sceloporus spinosus floridanus. Bull. Univ. Texas. Sci. Ser. No. 15: 1–24.
Oliver, W. R. B., 2nd ed. 1955.New Zealand Birds. Revised and Enlarged edition: 1–661. A. H. & A. W. Reed, Wellington.
Pearson, O. P., 1954. Habits of the Lizard Liolaemus multiformis multiformis at high altitudes in Southern Peru.Copeia 1954, No. 2. 111–116.
Rodgers, T. L., and Memmler, V. H., 1943. Growth in the Western Blue-Tailed Skink.Trans. San Diego Soc. Nat. His. 10: 61–68.
Stebbins, R. C., 1954. Natural History of the Salamanders of the Plethodontid Genus Ensatina. Univ. Calif. Publ. Zool. 54 (2): 47–124.
—— and Robinson, H. B., 1946. Further Analysis of a Population of the Lizard Sceloporus graciosus gracilis. Univ. Calif. Publ. Zool. 48 (3): 149–168.
*Strahl, 1892. Die Ruckbildung reifer Eierstockseier in Ovarium von Lacerta agilis. Verhandl. Anat. Gesellsch. Wien.
Taylor, E. H., 1936. A Taxonomic Study of the Cosmopolitan Scincoid Lizards of the Genus Eumeces with an Account of the Distribution and Relationships of its Species. Univ. Kansas. Sci. Bull. No. 22: 207–218.
Weekes, H. C., 1927. Placentation and other Phenomena in the Scincid Lizard Lygosoma (Hinulia) quoyi. Proc. Linn. Soc. N. S. W. 52 (4): 499–554.
—— 1929. On Placentation among Reptiles. I. Proc. Linn. Soc. N. S. W. 54 (2): 34–60.
—— 1930. On Placentation among Reptiles. II. Proc. Linn. Soc. N. S. W. 55 (5): 550–576.
—— 1934. The Corpus Luteum in certain Oviviparous and Viviparous Reptiles. Proc. Linn. Soc. N. S. W. 59 (6): 380–391.
—— 1935. A Review of Placentation among Reptiles with Particular Regard to the Function and Evolution of the Placenta.Proc. Zool. Soc. London. 1935. 625–645.
Wodzicki, K. A., 1950. Introduced Mammals of New Zealand: 1–255 D. S. I. R. Bull. 98, Wellington.
R. E. Barwick., M. Sc.,
Department of Zoology. Victoria University of Wellington, P. O. Box 196, Wellington, New Zealand.
[Footnote] *Not available during the course of this study.
Some New Cestodes from New Zealand Marine Fishes
[Received by the Editor February 28, 1958.]
Five new species of cestodes from marine fishes of New Zealand are described: Acanthobothrium wedli from Raja nasuta; Echinobothrium coronatum from Mustelus lenticulatus; Gymnorhynchus (Molicola) thyrsitae from Thyrsites atun; Gymnorhynchus (Gymnorhynchus) isuri from Isurus glaucus; Prochristianella aetobatidis from Aetobates tenuicaudatus.
Relatively few cestodes have been collected from fishes of the southern oceans. In New Zealand up till the present time, cestodes have received scant attention, particularly with regard to the cestodes of marine fishes. In Hutton's “Index Faunae Novae-Zealandiae ” (1904) appears a list of cestodes from New Zealand which includes species recorded from marine fishes.
Leiper and Atkinson (1914) described “a peculiar Tetrarhynchus larva ” from the “barracouta ” Lepidopus caudatus and Perrenoud (1931) described a new species of Acanthobothrium from Trygon pastinaca. Both these host identifications are doubtful.
The five new species of cestodes described were collected during the examination of 206 hosts comprising 46 species of 45 genera of fishes.
No new techniques have been employed for fixing, preserving or staining. Material was fixed in hot 70% alcohol. Histological sections were stained with Ehrlich 's haematoxylin and counter-stained with eosin in 95% alcohol. Type specimens are deposited in the type collection of the Dominion Museum, Wellington, and paratypes in the Department of Zoology, Victoria University College, Wellington.
Family Onchobothriidae Braun, 1900
Acanthobothrium wedli n. sp (Figs. 1–6.)
This species was collected from the spiral valve of Raja nasuta Mueller and Henle. Five adults were collected from a host specimen taken at Petone Beach in November, 1954. Three further specimens were collected from the same host species caught at Portobello, Otago Harbour, in 1952.
The following is an account of the holotype:
The entire worm measures approximately 130.0 mm in length, with a maximum width of 3.0 mm. The rather small scolex 0.47 mm in length is compact with four sessile bothridia. Each bothridium, up to 0.35 mm × 0.23 mm, is divided into three loculi by two muscular septa, the anterior loculus being the largest. The bothridia are muscular with the posterior margins projecting from the surface of the scolex. Anterior to the large loculus, each bothridium bears a pair of bifurcated books 0.097 to 0.105 mm in length. The two prongs of each hook are almost equal in size. There is no accessory sucker anterior to each bothridium Immediately behind the scolex the neck is narrow, but it soon enlarges into a thick tubular region 0.84 mm in diameter which tapers posteriorly. The first proglottids are visible about 7.0 mm posterior to the scolex and are many times broader than long. Near the extreme posterior end of the strobila the acraspedote proglottids become longer than broad. The whole strobila is flat and ribbon-like, with the thread-like everted cirri clearly visible along the lateral margins.
The distinctly two layered cuticle 0.005 mm thick, is usually more conspicuous in cross section near the lateral margins of the proglottis. The musculature consists of a thin layer of extremely fine longitudinal muscle fibres below the cuticle and a well-developed layer of large longitudinal muscle fibres at the junction of the cortex and medulla. The internal fibres are irregularly grouped into fascicles.
In the medulla towards the lateral margins of the proglottis are located the excretory canals. The dorsal canal is the more difficult to identify, but when present is about the same size as the conspicuous ventral canal. Close to each lateral margin of the proglottis is situated a nerve trunk 0.027 mm in diameter.
The testes are arranged in a single, closely packed layer in the medulla, anterior to the ovary. Each irregularly oval testis has a thick muscular wall and measures up to 0.150 mm in width. The testes number 80–100 per proglottis. In the mature region of the strobila, the vas deferens occupies a considerable part of the medulla in the median region of the proglottis. The distal portion of the vas deferens extends laterally, dorsal to the vagina to enter the cirrus pouch. Inside the cirrus pouch, the vas deferens forms a ductus ejaculatorius, which gives rise to the cirrus. When the cirrus is invaginated, the cirrus pouch is distended and rounded, but when evaginated, the pouch is narrow and elongated. The cirrus is a long narrow structure swollen at the base. It has a thick cuticle and is covered by rows of fine hairs.
When the cirrus is invaginated, the enlarged distal portion of the vagina opens into a short genital atrium, situated ventro laterally, near the middle of the margin of the proglottis. However, when the cirrus is evaginated, the distal portion of the vagina is also evaginated, so that it opens anterior to the cirrus on a small papilla. In this way the genital atrium is obliterated and the male and female ducts open to the exterior separately. The vagina passes medially, ventral to the vas deferens, then coils posteriorly to expand into the receptaculum seminis anterior to the ovarian isthmus. The two large, lateral lobes of the ovary are connected medially by the narrow isthmus. The lateral margins of the ovary are distinctly tabulate. From the posterior margin of the isthmus arises the large and extremely muscular oocapt, 0.065 mm in diameter. From the oocapt, the oviduct extends posteriorly to receive the narrow fertilization duct and finally enters the large shell gland. From the shell gland arises the uterine duct which extends anteriorly. The vitelline follicles are arranged in two lateral fields, slightly medial to the nerve trunks. The vitelline ducts and reservoir were not observed.
In the terminal gravid region of the strobila, the uterus distended with eggs, occupies practically the whole of the proglottis. It is not a simple sac-like cavity, but has numerous finger-like extensions which reach the lateral, anterior and posterior margins of the proglottis. In cross-sections of a gravid proglottis, only the cuticle and a thin layer of cortex are present apart from the uterus. The eggs are round, thin-walled, and up to 0.020 mm in diameter.
The following is a description of the two paratypes. The strobila does not appear flat and ribbon-like because of contraction during fixation inside the spiral valve of the host. The scolex is 0.30 mm to 0.36 mm in length and 0.16 mm to 0.23 mm wide at the posterior margin of the bothridia. Except for the strongly projecting posterior margins of the bothridia, the scolex is compact. Each bothridium is divided into three loculi by two transverse muscula septa, towards the posterior margin of the bothridium. Anterior to each bothridium is a pair of stout bifurcated hooks, 0.097 mm to 0.105 mm in length. The hooks are slightly inclined towards each other anteriorly, and consist of a broad base and two almost equal, posteriorly directed prongs. There is an extensive cavity inside the hooks which extends into the prongs. The scolex does not bear any accessory suckers.
Immediately posterior to the scolex, the neck expands into a tubular transversely wrinkled region 7.3 mm to 8.0 mm long and 0.70 mm to 0.94 mm in diameter. In one specimen, the posterior limit of this region is very conspicuous. Throughout the strobila, the size and shape of the proglottids varies considerably due to differences in the degree of contraction. The weakly craspedote nature of the proglottids is much more clearly shown than in the holotype. The total length of the complete worm is 80.0 mm, that of the incomplete specimen approximately 65.0 mm.
The original description of the genus Acanthobothrium by van Beneden (1850), in which he stated the two hooks of each bothridium are united, has been modified by Beauchamp (1905) and Pintner (1928), who agree that although the hooks may be closely approximate, they are not joined. Southwell (1925) and Verma (1928) separate the species of this genus primarily on total hook length. Dollfus (1926), discussing A. crassicolle, considers that hooks of even a single specimen
Text-fig. 1.—Acanthobothrium wedli n. sp. 1, Scolex, lateral view. 2, Mature proglottis. 3, T. S. through cirrus pouch. 4, Gravid proglottis. 5, T. S. posterior to ovarian isthmus. 6, Hooks from anterior margin of bothridium.Echinobothrium coronatum n.sp. 7, Scolex, lateral view. 8, Rostellar hooks. 9, Entire worm. 10, Hooks from Kopfstiel.
are not identical in form and dimensions—a view partially supported by Perrenoud (1931). Also the taxonomic importance of the number and size of the accessory suckers has been questioned by Perrenoud (1931) and others.
Baer (1948), reviewed and revised species of Acanthobothrium and recognises fourteen species with two species inquirendae. Baer considers the total length of the strobila, the number of testes and the ratio of the lengths of the hook handle, internal prong and external prong, to total hook length, as more satisfactory taxonomic characters. Perrenoud (1931) described A. intermedium as a new species from Trygon pastinaca, taken at Tauranga, New Zealand. Baer (1948) lists the host species as Dasyatis pastinaca and regards. A. intermedium Perrenoud, 1931 proper, as identical to A. crassicolle Wedl, 1855.
Acanthobothrium wedli closely resembles.A. microcephalum Alexander, 1953, in the total length of the hooks, the size of the scolex, and the number of testes. In A. wedli, however, accessory suckers are lacking; there is no velum-like fold which attaches the posterior part of each bothridium to the neck; the hook handle is 0.070 mm long, the inner prong 0.027 mm and the outer prong 0.035 mm long, while in A. microcephalum the length of the hook handle is 0.036 mm and the two prongs measure 0.064 mm in length. The strobila of A. wedli is much wider and the testes, up to 0.150 mm in diameter are considerably larger than those of A. microcephalum which are 0.023 mm to 0.038 mm in diameter. Proglottis shape showed so much variation that it is not regarded as significant.
Echinobothrium coronatum n. sp. (Figs. 7–10.)
A single specimen of this species was collected from the spiral valve of Mustelus lenticulatus Phillips from Wellington Harbour in March, 1954. Three detached proglottids were also found in the spiral valve.
The following is an account of the holotype:
The worm is 6.5 mm long and consists of the scolex, a region with longitudinal rows of hooks called the “Kopfstiel” by German writers, and the strobila, which is made up of 21 distinct proglottids.
The two comparatively shallow bothridia 0.380 mm in length, are armed with small spines on their outer surface. Spines do not cover the entire bothridial surfaces, but only occur near the base. Anteriorly, the scolex terminates in a large muscular disc which bears two separate groups of hooks arranged dorsally and ventrally. Some hooks are missing from one of these groups. The central region of the intact group is armed with twenty stout hooks. The largest of these hooks 0.118 mm long are medial, the smallest 0.035 mm long, are lateral. On each side of this central group of stout hooks is a lateral group of 14 fine hooks arranged in two alternate rows and measure up to 0.032 mm in length.
Posterior to the bothridia is a region called the “Kopfstiel”, 1.30 mm in length, which is armed with 8 longitudinal rows of hooks. The largest hooks 0.095 mm in length are situated anteriorly. Each hook consists of a long, straight, tapering shaft and a tri-radiate base which is attached to the surface of the “Kopftsiel”. There are 32 hooks in each row and the size of the hook shaft decreases posteriorly. This region of characteristic hooks is sharply distinguished from the strobila by a constriction.
The strobila is entirely acraspedote and consists of approximately 21 distinct proglottids, and also three detached proglottids. The three detached proglottids are greyish in colour, due to the accumulation of eggs in the uterus In the anterior 0.5 mm of the strobila no proglottids are distinguishable. The first visible proglottids are much broader than long, but soon become square in shape, while the most posterior ones are cylindrical and much longer than broad.
The ovary was clearly visible, situated near the dorsal surface and towards the posterior margin of the proglottis. The genital atrium is on the ventral surface slightly anterior to the ovary. The proximal region of the cirrus pouch is curved anteriorly and contains the cirrus proper, which is covered with bristles. The testes are comparatively large, up to 0.128 mm in diameter, and number 9–11 per proglottis.
Contained in the uterus are the eggs, which are irregular in shape, thin-walled, and up to 0.027 mm in diameter.
This species differs from those previously described in having some more hooks arranged in the two groups at the anterior end of the scolex. There is a total of 42 hooks in the complete group, the largest of which are bigger than any of those previously described. The large size of the hooks on the “Kopfstiel ” and also the large number of hooks making up a longitudinal row, distinguish it from other species. In other species the number of proglottids is smaller.
Family Gymnorhynchidae Dollfus, 1935
Gymnorhynchus (Molicola) thyrsitae n. sp. (Figs. 11–15.)
This larval form was collected from Thyrsites atun (Euphrasen), caught at Cape Campbell, Cook Strait. Twenty-eight host species have been examined, and in all but three this parasite has been found. When present, the number of worms varied between 3 and 286 in different host specimens. The most satisfactory method of counting the larvae was to fillet the fish, and remove the conspicuous opaque blastocysts rather than attempt to remove the parasite in toto. When removed from the flesh of the host and placed in Ringer 's solution, the blastocyst with the invaginated scolex could be seen moving about inside the fibrous outer capsule. Larvae removed from the flesh of the host which had been frozen for 10 days were found to be still alive. In the host specimen with 286 parasites present, only 15 were located in the dorsal muscle mass. Infestation occurred from a level just posterior to the cloaca, to as far forward as the cranium, with a few present also in the throat muscles. This distribution was found to be fairly constant. Although in three host specimens several parasites were found in the caudal region posterior to the cloaca, they were usually found anterior to this region. The region most heavily infested was the muscle near the ventral extremity of the ribs. In all the parasites collected, there were no signs of degeneration of the surrounding muscle, or of the muscle being absorbed by the parasite. From the comparatively few host specimens examined there did not seem to be any particular time of the year when infestation was more marked.
Considerable difficulty was experienced in bringing about the evagination of the proboscides. The most satisfactory method was to leave the larvae in Ringer 's solution for two hours, transfer to water at 65° C. for half a minute, and finally fix in hot 70% alcohol.
The following is an account of the holotype.
When the tough outer capsule was removed, the larva was seen to consist of a globose, densely white blastocyst which contianed the scolex, and a long narrow caudal extension. The extruded scolex is 4.6 mm m length. Anteriorly, the pars bothridialis is the widest region of the scolex, measuring 1.4 mm m width. Each ear-shaped bothridium has an entire margin which is not curled. The bothridia 1.01 mm × 0.63 mm are not inclined towards each other anteriorly and give a distinct “cross ”-shape to the pars bothridialis when viewed from the anterior end. The proboscides arise near the anterior end of the bothridia. The total length of a proboscide (by adding the portion evaginated to the portion invaginated; is 3.20 mm.
When the proboscide is evaginated there is a region at the base, 0.46 mm in length, which is without hooks, but this region was shorter in the remaining proboscides, which were not detached from the scolex. The basal armature is characterised by stout falciform hooks which are arranged around the base except on the middle of the external surface of the proboscide. The largest hooks in this region measure up to 0.135 mm in length, and the smallest hooks, which are the most posterior, measure 0.03 mm. Hooks of intermediate size are situated between them. On the external surface of the proboscide in the basal region are located a large number of hooks with broad bases of implantation, narrow relatively straight shafts and fine tips, which anteriorly merge into the band of fine microhooks.
Anterior to the basal armature, on the internal surface of the proboscide is another characteristic region of hooks arranged in two lateral groups and joined by some reduced hooks. One lateral group consists of obliquely transverse rows of hooks which vary greatly
Text-fig. 2.—Gymnorhynchus (Molicola) thyrsitae n. sp. 11, Entire larva. 12, Scolex and anterior region of blastocyst. 13, Internal surface of distal region of proboscide. 14, External surface of distal region of proboscide. 15, Characteristic armature anterior to the basal region of proboscide.
in shape, as shown in Fig. 8. The hooks of the most anterior rows up to 0.015 mm in length, are stout with a broad base and a low recurved shaft. The most posterior rows consist of hooks up to 0.032 mm in length, with an extremely narrow base, a long narrow shaft and a sharply recurved tip. The group towards the other lateral margin of the internal surface of the proboscide, consists of obliquely transverse rows of hooks which have a constant shape. The broad base of implantation of these hooks is narrow anteriorly and rounded posteriorly, and from the base arises a short, stout shaft.
The hooks of the metabasal region of the proboscide are arranged in obliquely-transverse ascending half turns. Hook 1, 0.050 mm long, is thick and rose-thorn shaped with a strongly-projecting anterior region of the base of implantation. Hooks 1 and 1 ′ are inclined towards each other at the middle of the internal surface of the proboscide. The remaining hooks of the row are falciform and finally decrease in size towards the middle of the external surface. Hooks 2 and 3, 0.067 mm long, have a sharply recurved tip, hooks 4 and 5, 0.075 mm in length, have the tip distinctly flattened, while hooks 6 to 9 show a gradual decrease in length and thickness of the shaft. The middle of the external surface of the proboscide is occupied by a longitudinal band of small hooks, between 0.020 and 0.025 mm long, which have no expanded base of implantation.
Text-fig. 3.—Gymnorhynchus (Gymnorhynchus) isuri n. sp. 16, Scolex, bothridial surface. 17, Scolex, antibothridial surface. 18, T. S. of immature proglottis. 19, Whole mount of immature proglottis. 20, Entire worm. 21, Large hooks on the internal surface of a proboscide. 22, Double chainette on the external surface of a proboscide. 23, Hooks of double chainette. 24, Proximal region of proboscide, external surface. 25, Proximal region of proboscide, internal surface.
The pars vaginalis is not distinguished externally from the pars bulbosa. The pars bulbosa contains the four muscular bulbs, 0.77 mm × 0.26 mm. Internally, the retractor muscle of the proboscide is attached to the posterior wall of the bulb. There is a constriction between the pars bulbosa and pars post bulbosa. The pars post bulbosa is attached to the oval, wrinkled blastocyst which gives rise to a long narrow caudal extension.
Gymnorhynchus (Molicola) thyrsitae n. sp. differs from the other species of this sub-genus—Gymnorhynchus (Molicola) horridus (Goodsir), 1841, in the following characters:
The scolex invaginates in the blastocyst and is not curved around it.
The bothridial margins are not thick and rounded.
The characteristic armature of the internal surface of the proboscide immediately anterior to the basal armature.
The flattened tips of hooks in approximately the middle region of a half-turn of principal hooks.
Gymnorhynchus (Gymnorhynchus) isuri n. sp. (Figs. 16–25.)
A single specimen of this species was collected from the spiral valve of Isurus glaucus (Mueller and Henle) caught at Makara, Cook Strait, in June, 1955.
The bothridia, arranged in pairs on the dorsal and ventral surfaces of the scolex, are muscular and conspicuous. In lateral view the bothridia have strongly projecting, rounded posterior borders. Each bothridium is ear-shaped, measuring 2.66 mm in length and 1.21 mm in width. The bothridial cavities are deep and the bothridial margins are entire and rounded. The pars vaginalis 1.05 mm in length, is followed by the pars bulbosa 3.51 mm in length and slightly swollen in lateral view. The pars post bulbosa is extremely short and its posterior limit is indicated by a slight constriction. The strobila measures 77.0 mm in length and the first visible proglottids appear close to the posterior margin of the pars post bulbosa. Anteriorly the proglottids are much broader than long, but towards the posterior end of the strobila they increase in length until the terminal three proglottids are as long as they are broad.
The proboscides arise from the anterior margins of the bothridia. When the worm was first removed from the spiral valve of the host, the proboscides were invaginated, but when the scolex was placed in warm water they evaginated extremely rapidly.
The length of the proboscides varies between 8.0 mm and 10.2 mm when completely evaginated. When the proboscide is evaginated there is a short region at the base up to 0.6 mm in length which is without hooks. The basal armature consists of a ring of from 13 to 15 hooks of widely varying size. The smallest hooks are situated on the external surface of the proboscide. All the hooks of this region have narrow bases with long, slightly curved shafts and rounded tips. The largest hook in this region measures 0.265 mm. Anterior to the basal armature the hooks are arranged in transversely ascending half turns. The size and shape of the hooks varies at different levels of the proboscide. In the proximal metabasal region up to 2.0 mm in length the hooks have narrow shafts and reduced bases of implantation. In the most distal 1.5 mm of the proboscide the hooks decrease rapidly in size. The following figures apply to hooks between these two regions. There is a narrow region between hooks 1 and 1 ′ (i.e., the middle of the internal surface of the proboscide) which is without hooks. Hook 1 is stout, with a broad base of implantation and thick shaft, measuring up to 0.168 mm in length. Hooks 2 to 6 are finer with a slightly curved shaft and up to 0.140 mm in length.
The remaining hooks in each half-turn become smaller towards the middle of the external surface of the proboscide, with the final hook of the half turn up to 0.085 mm in length. The middle of the external surface possess hooks arranged in a double chainette characteristic of the sub-genus Gymnorhynchus. Each hook consists of a narrow, slightly curved shaft and a base which curves laterally. The convex surface of the hooks of the two rows approach one another. The hooks of the double chainette are up to 0.055 mm in length.
The proboscide sheaths are sinuous but not densely coiled and contain the retractor muscles of the proboscides which are attached to the base of the muscular bulbs.
The internal musculature of the proglottids is well developed. Scattered sub-cuticular muscle fibres are located immediately below the extremely thin cuticle. The deeper musculature consists of a conspicuous layer of longitudinal muscle fibres arranged in fascicles in the cortex. At the junction of the cortex and medulla is a layer of circular muscle fibres. The proglottis musculature is completed by scattered dorso-ventral muscle fibres which extend across the medulla.
The excretory system consists of a pair of longitudinal canals located in the medulla towards the lateral margins of the proglottis. On each side the dorsal canal is much smaller than the ventral canal. Near the posterior margin of the proglottis the large ventral canals
Text-fig. 4. —Prochristianella aetobatidis n. sp. 26, Entire worm. 27, Pars bothridialis and pars vaginalis. 28, Detached muscular bulb. 29, T. S. at level of ovary. 30, T. S. posterior to cirrus pouch. 31, Internal surface of proboscide. 32, External surface near distal extremity of proboscide. 33, Internal surface of basal region. 34, External surface of basal region. Corrigenda: the scales in Figures 29–34 should read 0.1 mm.
are joined by a transverse excretory canal. Lateral to the excretory canals are the longitudinal nerve trunks. Each nerve trunk is a relatively large, fibrous rounded structure, 0.05 mm in diameter.
Some details of the reproductive system are not described as the proglottids had not reached maturity. The testes form a testicular field in the median region of the medulla. From the anterior median region of the proglottis the vas deferens coils laterally and dorsally to enter the cirrus pouch which lacks a muscular wall. The invaginated cirrus was clearly visible but the genital atrium was not seen. Extending ventrally below the cirrus pouch the vagina passes posteriorly to the level of the ovary close to the posterior margin of the proglottis. The incipient uterine pore is located slightly anterior to the proximal margin of the cirrus pouch.
According to Dollfus (1942), a description of an adult belonging to the sub-genus Gymnorhynchus has not been published. Pintner (1929), described a specimen consisting of a scolex and an appendix, but which showed no signs of proglottis formation.
This adult specimen differs from previous descriptions of the larva of Gymnorhynchus (G.) gigas in having the posterior margins of the bothridia of the same face closely approximating. Also, when viewed from above the anterior margin of the scolex, the posterior bothridial margins project strongly. The naked region at the base of the proboscide is much shorter than in G. (G.) gigas. The hooks of the basal armature are fewer in number and clearly differentiated from the metabasal armature. The maximum size of the hooks of the basal armature is larger than that of G. (G.) gigas and although small, hooks are present on the external surface of the proboscide in the basal region. The maximum length of the proboscides is also greater than that of G. (G.) gigas.
Family Eutetrarhynchidae Guiart, 1927, emended Dollfus, 1942
Prochristianella aetobatis n. sp. (Figs. 26–34.)
In March, 1955, a specimen of Aetobatis tenuicaudatus (Hector) was examined. The spiral valve contained a large number of this parasite. When removed from the host and placed in Ringer 's solution, a bright orange-red spot was clearly visible near the posterior region of the pars vaginalis. On preservation the colour rapidly disappeared. The posterior proglottids were often detached from the strobila by agitation of the parasite and many free proglottids were found in the contents of the spiral valve.
The following is a description of the holotype:
The two bothridia are shallow, 0.41 mm in length, with slightly curled margins. In lateral view the two bothridia are inclined towards each other anteriorly. The pars vaginalis 0.784 mm in length is widest immediately behind the bothridia where it measures 0.49 mm. The pars bulbosa is 1.358 mm in length, and is followed by the very short pars post bulbosa. Measurements of the holotype (A) and four paratypes (B-E) are given below:
The formation of proglottids begins almost immediately posterior to the pars post bulbosa. The anterior proglottids are broader than long but posteriorly they increase in length until the most posterior proglottis (i.e., the sixteenth visible proglottis) is 1.15 mm in length and 0.45 mm in width.
The proboscides arise from the anterior margins of the bothridia. The total length of a proboscide is 1.76 mm. In the proximal metabasal region the diameter is 0.07 mm, but decreases to 0.05 mm towards the distal extremity. The basal region of the proboscide is narrow proximally but enlarges distally to a maximum width of 0.085 mm. The basal armature consists of six transversely ascending rows of principal hooks arranged in half turns. These hooks have a broad base, a long narrow shaft and a fine tip. There is a a steady decrease in the size of the hooks from the internal to the external surface of the proboscide. Also on the external surface, at the distal extremity of the basal region are situated three very stout
hooks with an extremely broad base 0.024 mm wide, and a small recurved point. The remainder of the proboscide is armed with obliquely transverse rows of hooks arranged in half-turns, those of one face alternating with those of the other. Each half-turn comprises 12 hooks, the longest of which, 0.036 mm, is near the mid-line of the internal surface, the remaining hooks of the half-turn decreasing regularly towards the external surface of the proboscide. The proboscide sheaths are sinuous without being tightly coiled. When the pro-boscides are invaginated they extend about one-third the distance into the cavity of the muscular bulbs, and are followed by the retractor muscles which are attached to the posterior margin of the bulbar cavity. The muscular bulbs are 1.358 mm in length by 0.15 mm in width.
The proglottis musculature system is poorly developed. Beneath the thin cuticle is a laver of longitudinal subcuticular muscle fibres. Deeper in the cortex are scattered longitudinal and circular muscle fibres.
The excretory system consists of a small dorsal canal and a large ventral canal situated near the lateral margins of the medulla. Lateral to the excretory canals are the longitudinal nerve trunks.
The testes are arranged in two longitudinal rows from the anterior margin of the proglottis to a level just anterior to the ovary. They are relatively large, up to 0.18 mm deep, with a thick muscular wall. The vas deferens is a tightly coiled duct which arises at the level of the ovary and extends anteriorly then laterally to expand into an external seminal vesicle, before entering the cirrus pouch. The large ductus ejaculatorius contains the invaginated cirrus.
The genital atrium opens at the lateral margin at about the beginning of the posterior third of the proglottis. The distal extremity of the vagina has a thick muscular wall and opens into the genital atrium ventral to the cirrus pouch. The vagina extends posteriorly in the ventral region of the medulla to a level slightly anterior to the ovarian isthmus, where it expands into the receptaculum seminis. The ovary, which occupies most of the medulla consists of four large lobes joined by the ovarian isthmus. From the receptaculum seminis the fertilization duct passes dorsally over the ovarian isthmus and then ventrally to join the oviduct. The oviduct arises on the ventral surface of the ovarian isthmus at the muscular oocapt It then extends posteriorly and receives firstly the fertilization duct and then the vitelline reservoir before entering the shell gland. From the shell-gland, the uterine duct extends anteriorly and gives rise to the uterus. Even in the most posterior proglottis the uterus did not contain any eggs. The vitellaria occupy most of the cortex anterior to the ovary.
Dollfus (1957) notes that the name of the type species of the genus Prochristianella is P. papillifer (Poyarkoff, 1909). P. aetobatidis differs from P. papillifer in the following respects: (1) the proboscides are approximately only half the length, (2) the basal armature consists of six rows of hooks arranged in half-turns, (3) three characteristic hooks are present at the junction of the basal and metabasal regions, (4) the metabasal armature does not show the increase and subsequent decrease in the size of the hooks.
From the short description of Linton (1890) and that of Dollfus (1946), ? Prochristianella tenuispinis (Linton, 1890) differs from P. aetobatidis particularly in hook size and arrangement.
Alexander, C. G., 1953. Five New Species of Acanthobothrium (Cestoda: Tetraphyllidea) from Southern California Rays. J. Parasit 39 (5), 481–486.
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E. S. Robinson,
The University of Nebraska, Department of Zoology, Lincoln 8, Nebraska, U.S.A
Explanation of Text-Figs.
The following abbreviations are used in Text-fig. 1–4: —
BA, basal armature
CE, caudal extension of blastocyst
CP, cirrus pouch
DC, double chainette
DEX, dorsal excretory canal
DE, ductus ejaculatorius
EXC, excretory canal
FD, fertilization duct
LM, longitudinal muscle
MB, muscular bulb
NT, nerve trunk
PBL, pars bulbosa
PS, proboscide sheath
PV, pars vaginalis
RM, retractor muscle
SH, shell gland
TEX, transverse excretory canal
UP, uterine pore
UTD, uterine duct
VD, vas deferens
VEX, ventral excretory canal
VR, vitelline reservoir.
Spiral Segmentation in Two Species of New Zealand Weta (Orthoptera, Gryllacridoidea, Henicidae)
Two examples of naturally occurring spiral segmentation, one on an immature female specimen of Deinacrida carinata Salmon, and the other on an adult female of Hemideina crassicruris Salmon, are described and illustrated. These are the first examples of this abnormality recorded from the Orthoptera Saltatoria.
Spiral segmentation, sometimes termed helicomerism, has been recorded from orthopterous insects by Cappe de Baillon (1937), who observed it in the phasmid Dixippus morosus (Br.), and by Balazuc (1955), who recorded it from the mantid Mantis religiosa L., in which it had been experimentally induced, and from the earwig Forficula auricularia L., in which it was naturally occurring. This abnormality is well known amongst the Lepidoptera, Hymenoptera, and Diptera, from all of which a number of examples have been described by Cockayne (1929, 1934 et al.) and other authors. In these orders it has been studied in some detail and has been experimentally induced by treatment of eggs with heat, ultra-violet rays or by mechanical stimulation. Balazuc induced it in the mantid by mechanical stimulation of the ootheca. As far as can be ascertained there are no records of spiral segmentation occurring in Orthoptera Saltatoria in the literature, hence the examples described below are the first recorded from this group of insects.
The first is a penultimate stage female Deinacrida carinata Salmon, collected at Herekopare Island, Foveaux Strait, during May, 1954. In this specimen the fourth, fifth, and sixth abdominal segments are helicomerous (Fig. 1). The fifth tergite is the only one which is divided, its right hemitergite being medially fused with the fourth tergite and the left with the sixth tergite. These junctions are indicated by a longitudinal ridge such as normally occurs medially on the fifth, sixth, seventh, and eighth tergites, and which is therefore not a deformity. Apart from this the junctions are almost completely undistorted and lack any sign of previous injury. The sternal region of the abdomen is normal.
The second example is an adult female specimen of Hemideina crassicruris Salmon, captured on Stephen 's Island, Cook Strait, during December, 1954. Here the seventh, eighth and ninth abdominal segments are helicomerous (Fig. II), all the other segments being normal. The right hemitergite of the eighth segment, normal in size, is fused medially with the seventh tergite, and the left hemitergite which is very much smaller and only weakly developed, is medially fused with the ninth tergite. A certain amount of buckling and distortion which has occurred at the junction of these segments, suggests that the abnormality may have been caused by injury to the insect during a juvenile stage. The sternal region is normal.
As Balazuc suggests, helicomerism is rare in the Orthoptera, these examples being the only two encountered during the examination of many specimens of different species of New Zealand weta.
[Footnote] * Prepared during the tenure of a New Zealand University Research Fellowship.
Both specimens are dried and have been placed in the Entomological Collections of the Dominion Museum, Wellington.
Helpful criticism offered by Dr. Salmon during the preparation of this note is gratefully acknowledged.
Balazuc, J., 1955. La T ératologie des Orthopt éroides. A propos de quelques nouveaux faits observationnels et exp érimentaux. Boll. Lab. Ent. agr. Portici, XIV: 48–64, 1 pl.
Cappe de Baillon, P., 1927. R écherches sur la t ératologie des Insectes. Encycl. ent. 8: 291 pp., 85 figs., 9 pls.
Cockayne, E. A., 1929. Spiral and Other Anomalous Forms of Segmentation. Trans. ent. Soc. Lond. LXXVII (II): 177–184, pls. XIII-XV.
—— 1934. Spiral and Other Anomalous Forms of Segmentation with an Account of Three Ventral Spirals in One Brood of Hadena dissimilis Kn. Trans. R. ent. Soc. Lond. LXXXII (I): 165–172, pls. III-V.
Salmon, J. T., 1950 A Revision of the New Zealand Wetas, Anostostominae (Orthoptera: Stenopelmatidae). Dom. Mus. Rec. Ent. 1 (8): 121–177.