masterly style by the same able author. As the journals in which Beddard's papers are published are expensive, and, for the most part, inaccessible to general readers in New Zealand, I propose to give an abstract of each paper, embodying the principal anatomical details of each species, and to record some further observations on the habits of both native and introduced terrestrial and aquatic forms.

Since the publication of Darwin's famous treatise on the formation of vegetable mould by earthworms, the habits of this much-neglected group are now receiving the attention of younger naturalists in other countries, and already the literature of the subject is considerable. The breeding habits of worms have not, however, received much attention, and any accurate notes on them made during the breeding-season will be acceptable to naturalists. When living at Lake Brunner, in 1887–88, I devoted considerable time to the habits of worms living in the primeval forest, and since then I have had opportunities of studying them for a year in Victoria, and latterly at Ashburton, New Zealand. The cocoons of earthworms, their time of deposition, and the development of the embryos have interested me much for many years. In recording the facts ascertained by the careful study of worms, I may say that I do so in the hope of stimulating others to the study of these highly beneficial and interesting animals. It may be added that there is every possibility of many new species still remaining to be added to the list, the discovery of which is always a pleasure. In remote, humid islands like those of New Zealand, which have been long separated from any extensive land area, the conditions are more favourable for the preservation of old ancestral forms. We fully realise this fact in many endemic species among the higher groups of animals, and it appears to be further realised in earthworms, as a New Zealand species (Deinodrilus benhami) forms the basis of Beddard's genealogical tree of Acanthodrili. The genus Acanthodrilus is largely represented in New Zealand; and, of the twenty-seven recorded species, seven are from New Zealand. Mr. Beddard has, in addition to these, two or three new species as yet undescribed, and doubtless many more remain to be discovered. The genus Perichœta will, I believe, also prove to be well represented in the number of species, as the natural conditions are very favourable to their habits. The three endemic species of aquatic Oligochœta described by Beddard represent separate genera, and they are sufficiently interesting to students of the group. A number of introduced terrestrial and aquatic species occur in many districts in New Zealand: these will presently be noticed separately.

In his remarks on the habits of earthworms, and the occurrence of their castings in forests, Darwin stated that, “In

Venezuela, castings, probably ejected by a species of Urochœta, are common in the gardens and fields, but not in the forests, as I hear from Dr. Ernst, of Caracas.”^* In the forests of Westland I was unsuccessful in finding a single casting, except where the bush had been cleared, and trodden by cattle. In the more remote untrodden bush the roots of ferns and mosses, of seedling and sapling trees and shrubs, form a dense network of considerable depth, in which worms do not appear to exist. We found them occasionally under fallen and decayed logs, and they are exceedingly numerous in the dark-coloured subsoil underlying the débris and roots of the forest. The subsoil in many parts is extremely rich, and doubtless formed the original surface mould of the country before the now magnificent forest spread over it. The small bush-clearings made by settlers are soon compressed by cattle, and in a few years the castings of earthworms are ejected plentifully on the surface. In the valley of the Grey River the older bush-clearings produce a rich growth of English grasses, and worms are plentiful in the soil. Where well-trodden paths or land exist their castings abound in great numbers. When digging for specimens we obseryed the varying depths of the superficial mould overlying the original layer of forest débris. Some of the clearings are twenty and twenty-five years cleared, and several of the sections we examined showed distinct layers of surface-soil, varying from 7in. to 11in. in depth. The original layer of forest mould was distinctly traceable, which also varied considerably in depth. This rate of accumulation of mould is greater than any results given by Darwin, at least during the period of time it accumulated. If, however, we consider the extremely humid and mild climate of Westland generally at all seasons of the year, the result is perfectly reconcilable. Darwin's researches on the accumulation of mould by earthworms were carried on in England, which country cannot compare with the mild and humid climate of Westland, at least in the natural conditions favourable for the actions and increase of worms.

The introduction, great increase, and rapid dispersion of alien forms may be briefly discussed here. No doubt the several species of British and other exotic worms now common in New Zealand have been introduced at various times in the soil of plant-cases, and in the soil used as ships' ballast. The phenomenal increase of aliens is due chiefly to the genial climate, and to the absence of their natural enemies. The rich land in many parts of the country is also very favourable to their increase. The rapid dispersion of introduced worms is due to the distribution of trees and shrubs from nurseries,

and to the extensive system of planting English trees in nearly all parts of the country, which has proceeded for many years.

The habits of British earthworms are so well known to naturalists that, as they cannot differ materially in New Zealand, little need be said about them. I may, however, mention a few items which are of interest. The prodigious destruction of earthworms during heavy rains and floods must check their increase considerably. Nevertheless they exist in some gardens in immense numbers. During the heavy rains in August last I observed several lawns and pieces of garden absolutely covered with a dense layer of castings. At the same time the destruction of worms was phenomenal. After a heavy night's rain, a slight frost occurred for several mornings at daybreak, and destroyed the worms crawling about the streets and footpaths in myriads. The street channels also convey vast numbers to the rivers, by which they are borne to the sea and thus perish.

The breeding habits of worms are not well known to naturalists: yet such is an important line of research. The cocoons are easily found in the habitats of worms, and are deposited in moist chambers excavated a little distance from the walls of their burrows, but never in the burrows they inhabit. They may be found throughout the year, but they are more numerous during winter and spring. Although I have carefully examined hundreds of adult worms annually for several years, I have never observed one in the act of fabricating a cocoon: I have, however, found the latter in all stages of development, ranging from the newly-deposited to mature cocoons with the young worms in the act of escaping from them. The cocoons of Acanthodrilus multiporus when newly deposited are dull-white in colour, and are very smooth and flaccid. They are filled with a white albuminous fluid which nourishes the embryo. The cocoons vary considerably in colour, according to their age and the stage of development of the embryos within them. From white they pass through several shades of yellow and brown to dark-red, which latter colour indicates maturation of the embryos. When the young worms emerge from the cocoons they are semi-transparent and delicate. The circulatory system is clearly visible for a few days, or until the integument thickens and assumes the uniform pale-pink colour of the young of this species. We have kept many cocoons of several species of indigenous worms, and observed the young emerging. The cocoon is composed of several layers of an extremely tough semi-transparent material, and as the embryo matures and presses upon the inner walls of the cocoon each layer generally yields in succession until the last opens, when the young worm slowly

emerges. The cocoon generally bursts longitudinally, and we have observed the inner mucous coating of the cocoon to be slightly tinged with blood after the worm had escaped. The time occupied, and the position of the young worm's body while emerging, varies according to the texture of the cocoon: some yield freely and allow the young worms to escape in a few hours without difficulty; others are stronger in texture, causing the time of emergence to be more prolonged. I cannot state accurately the time required for the full development of the embryos, as it must vary according to the conditions of the soil and temperature surrounding them. Judging by the colours of the cocoons changing as the embryos developed within them, and allowing that the cocoons may have been several days or weeks old when dug out of the soil, we found the worms to emerge at periods varying from eighty to a hundred and forty-two days. We endeavoured to ascertain the time of development by peeling off several of the thin outer layers of the cocoons, and holding them close to a bright lamp at night, and studying them with a strong lens. Although this method is not quite satisfactory, it nevertheless affords a fairly accurate means of ascertaining the approximate time required for the development and emergence of the embryos. I do not possess a copy of Beddard's paper on the anatomy of Acanthodrilus multiporus, A. novœ-zealandiœ, A. dissimilis, and another species or variety sent to him by Professor Parker, F.R.S., from the neighbourhood of Dunedin; but the following abstract of a paper^* on the development of A. multiporus presented by Beddard to the Royal Society two years ago will afford some idea of the interesting worm:—

“In the young embryos of this worm each segment is furnished with a pair of nephridia, each opening by a ciliated funnel into the segment in front of that which carries the dorsally-placed external pore. In later stages the funnels degenerate, and that portion of the tube which immediately follows the funnel becomes solid, losing its lumen; at the same time the nephridium branches, and communicates with the exterior by numerous pores. At a comparatively early stage, four pairs of gonads are developed in segments x.–xiii.; each of these is situated on the posterior wall of its segment, as in Acanthodrilus annectens, and not on the anterior wall as in the majority of earthworms. When the gonads first appear, the nephridial funnels, with which they are in close contact, are still ciliated, and their lumen is prolonged into the nephridium for a short distance. Later the cilia are lost, and the funnels increase greatly in size, while those of the neighbouring segments—in fact, all the remaining funnels—remain stationary

for a time, and then become more and more degenerate. The large funnels of the genital segments become the funnels of the vasa deferentia and oviducts. It will be observed that the number of ovaries and oviducal funnels (two pairs) at first corresponds to that of the testes and sperm-duct funnels; subsequently the gonads and commencing oviducts of segment xii. atrophy. Each of these large funnels is continued into a solid rod, which passes back through the septum, and then becomes continuous with a coiled tuft of tubules, in which there is an evident lumen, and which is a part of the nephridium of its segment. In the segments in front of and behind the genital segments the rudimentary funnels communicate in the same way with a solid rod of cells, which runs straight for a short distance, and then becomes coiled and twisted upon itself, and provided with a distinct lumen. In fact, apart from the relative size of the funnels and the presence of the gonads, it would be impossible to state from which segment a given section through the terminal portion of a nephridium had been taken. In a later stage the large funnels of the genital segments become ciliated, but this ciliation takes place before there is any marked change in the tube which is connected with the funnel.

“In the young worm which has just escaped from the cocoon the funnels are ciliated, and they are each of them connected by a short tube, in which a lumen has been developed, but which ends blindly in close proximity to a coil of nephridia. No trace of any nephridial tube other than the sperm-duct or oviduct could be observed, whereas in the preceding and succeeding segments the rudimentary nephridial funnel, and a straight tube leading direct to it from the bodywall, were perfectly plain. Dr. Bergh has figured, in his account of the development of the generative organs of Lumbricus, a nephridial funnel in close contact with the funnel of the genital duct. It may be suggested that a corresponding funnel has been overlooked in the embryo Acanthodrilus: the continuity of a structure, identical (at first) with the nephridia of the segments in front and behind, with the genital funnels, seems to show that a search for a small nephridial funnel would be fruitless.

“I can only explain these facts by the supposition that in Acanthodrilus multiporus the genital funnels and a portion at least of the ducts are formed out of nephridia. This mode of development is a confirmation, to me unexpected, of Balfour's suggestion that in the Oligochœta the nephridium is broken up into a genital and an excretory portion.

“In the comparison of the facts briefly described here with the apparently-independent origin of the generative ducts in other Oligochœta, it must be borne in mind that in Acantho-

drilus the segregation of the nephridium into several almost detached tracts communicating with the exterior by their own ducts precedes the formation of the genital ducts.”

Introduced Worms.—I here append a list of exotic species which we have collected in several localities in the South Island. They have been identified for me by Mr. Beddard and Mr. J. J. Fletcher, F.L.S., the author of several valuable papers on Australian earthworms.^*

• Microscoles modestus, Rosa (Endrilus (?) dubius, Fletcher).

• Allolobophora rubicunda, Eisen. (Lumbricus campestris, Hutton).

• " fœtidus, Sav. (Lumbricus annulatus, Hutton).

• " turgidus, Sav.

• " purpureus.

• " rubellus, Sav.

• Lumbricus terrestris.

• Allurus tetraedrus, Sav.

• Tubifex rivulorum.

The first-named species is one of wide distribution; it occurs in Australia, Tasmania, Norfolk Island, and New Zealand. It was first described by Dr. Rosa, who obtained a single specimen among some soil which had been brought to Genoa with plants from Buenos Ayres. Four months later it was described by Mr. Fletcher as Endrilus (?) dubius, which name must now be regarded as a synonym. There still, however, exists some doubt as to there being one or two species—a larger and a smaller form. Both forms are common in gardens at Ashburton, the smaller one inhabiting garden-soil, the larger form occurring in rubbish-heaps and old heaps of manure. Fletcher gives its measurements at 45mm. to 65mm. long, with a “clitellum of a yellow hue.” The clitellum of the smaller form occurring at Ashburton is reddish in colour, that of the larger one is distinctly yellow, while some specimens attain a length of 4in. and 4.½in. It is a robust species, and easily identified by its yellow posterior extremity.

The second and third species in the above list were described^† by Professor Hutton; his names, however, must now remain as synonyms. Allolobophora turgidus is another remarkable species, having a wide geographical range. It occurs in North America and Mexico, in many parts of Australia, Tasmania, and New Zealand. It is rapidly spreading and increasing everywhere where gardens are cultivated. Allolobophora purpureus is common in some districts in gardens, and A. rubellus occurs in moist soil on swampy flats,

found in many species of Lumbricus and Allolobophora, but is comparatively rare elsewhere. With regard to the vascular system, the only facts which I am able to record are—(1) the condition of the dorsal vessel; (2) the number and connection of the ‘hearts.’ The dorsal vessel is a completely-double tube, with the exception of that portion which lies in the first four or five segments. It resembles the dorsal vessel of Acanthodrilus multiporus in the fact that the tubes are perfectly separate throughout, except where they become permanently fused at the anterior extremity of the body. The somewhat contracted condition of the worm frequently caused the two halves of the dorsal vessel to become widely separate in the middle of each segment, while at the mesenteries they come into close relation: there is, however, no fusion of the two tubes at these points, such as occurs in A. novœ-zealandiœ and Microchœta. I observed six pairs of lateral ‘hearts,’ the last pair being in segment xiii.; the last four pairs are specially large, and are connected with the supra-intestinal as well as with the dorsal vessels. The anterior two pairs (there are probably one or two pairs in addition to those I have mentioned) are much more slender, and only connected above with the dorsal vessel.

“Septa.—The septa separating segments viii.—ix., ix.—x., x.—xi., xi.—xii., xii.—xiii., are thicker than the rest, but not to so marked a degree as is often met with in earthworms.

“Alimentary Tube.—The pharynx has the usual characters. The gizzard lies in segments vi. and vii.; the œsophagus is thick-walled and highly vascular, but there appeared to be no distinct calciferous glands. The intestine has a typhlosole. The nephridia are not obvious on dissection except in segments ii., iii., and iv.; in each of these segments is a tuft of nephridial tubules of considerable size; in the posterior segments nephridia are present, and open on to the exterior by several pores in each segment. The nephridial system of this worm is in fact like that of Acanthodrilus multiporus.

“In Deinodrilus the dorsal blood-vessel is surrounded by a special cœlomic space in a way that is, at present, unique among earthworms. This space does not appear to exist in the first fifteen segments; after this point the two dorsal blood-vessels are not as plainly visible on a dissection of the worm as they are anteriorly; the red colour of the blood is masked by the whitish colour of the tissues which form the walls of the perihæmal space. The fact that the blood-vessels are so clearly seen on dissection in the anterior segment leads me to infer that here there is no perihæmal cœlomic space; but I am unable to support this view by the microscopical appearance of the dorsal vessels in this region of the body, which I have not investigated by sections. The enclosure

of the dorsal blood-vessel in a special cœlomic sac suggests, of course, the pericardium of higher types, and in any case it may be compared with the condition of the cœlom in the Hirudinea, where the principal blood-vessels as well as other organs are often included in separate cœlomic spaces. Among the Chœtopoda also a commencement of a secondary subdivision of the cœlom is to be seen. In the Capitellidœ a series of longitudinal chambers enclose the nephridia and other organs, but I am not aware that hitherto anything of the kind has been described in the Oligochœta.

“Reproductive Organs.—The vesiculœ seminales occupy segments xi. and xii.; they are racemose organs like those of Acanthodrilus. The testes I have not seen. The vasa deferentia open by funnels in segments x. and xi.; the funnels of segment xi. are quite independent of the vesicula. I could not trace the course of the vasa deferentia, but in all probability they open, as in Acanthodrilus, upon the eighteenth segment. The atria are in segments xvii. and xix. The external apertures of these organs have been already mentioned. The atria themselves are so exactly like those of Acanthodrilus that no further description is necessary. The ovaries are situated on the anterior wall of segment xiii.; they are digitate bodies like those of Acanthodrilus. The oviducts open by funnels, which are placed near to each other, and on either side of the nervecord, on the posterior wall of segment xiii. The external pores are upon the fourteenth segment. The spermatheca has a very characteristic form…. The spermatheca is a somewhat oval pouch, which suddenly narrows into a slender duct, opening close to the anterior margin of the segment. At the junction of the pouch with the duct are three diverticula, two on one side and one on the other. The diverticula are very much smaller than the pouch, and of a regular oval form.

“The following table indicates the principal points in which Deinodrilus agrees with Acanthodrilus or Perichœta:—

[The section below cannot be correctly rendered as it contains complex formatting. See the image of the page for a more accurate rendering.]

reproductive organs of this species is, that the testes and ovaries, instead of being situated on the anterior wall of their respective segments, are placed upon the posterior wall in close proximity to the funnels. 1 should have been disposed to regard this arrangement as abnormal had it not been for the fact that it occurred in all of the two or three specimens studied by me. The vesiculœ seminales of this species are like those of other Acanthodrili in their racemose character, and in the fact that they do not envelope the funnels of the vasa deferentia. It may easily be seen in longitudinal sections of the worm that the vesiculæ, although so different in outward appearance from those of Lumbricus, only differ in being branched instead of simple outgrowths of the septa. The atria, as is always the case with Acanthodrilus, are two pairs situated in the seventeenth and nineteenth segments. The vasa deferentia, as also appears to be the rule in this genus, open quite independently of the atria upon the eighteenth segment. The two vasa deferentia unite just before their external orifice (♂), which is situated just on the boundary-line between the seventeenth and eighteenth segments; the pores are also situated in a groove which connects the two atrial pores of each side, and the presence of which is highly characteristic of the genus Acanthodrilus, as also of Deinodrilus. The two vasa deferentia run side by side, and obliquely, through the muscular layers of the integument to the external pores, crossing on their way the duct of the atrium of the seventeenth segment. In longitudinal sections I traced the vasa deferentia back to the thirteenth segment, running in the longitudinal muscular layer, and at some distance from the surface, nearly midway between the two surfaces of the longitudinal muscular layer; after this they gradually approach the peritoneal face of the muscular layer, and for the last portion of their course were imbedded in the peritoneum. I am not aware that in any other earthworm the vasa deferentia are known to run deep within the longitudinal muscular layer. As in A. multiporus, there appear to be no penial setæ. The ovaries are upon the posterior septum of the thirteenth segment, and are actually in contact with the funnel of the oviduct. The oviducts traverse the septum which separates segments xiii. and xiv.; the funnels are in the thirteenth segment. The spermathecœ are present to the number of two pairs, and are situated in segments viii. and ix. They are elongated narrow pouches, and each is furnished with two pairs of minute diverticula.

“Vascular System.—The dorsal vessel is double throughout, as in A. multiporus; the transverse hearts are especially conspicuous in the tenth, eleventh, twelfth, and thirteenth segments; the vascular trunks are, indeed, indistinguishable from those of A. multiporus, with which species the present

has several other points in common. It will be remembered that A. novœ-zealandiœ differs from the present species and A. multiporus in the fact that the two dorsal vessels are united where they perforate the intersegmental septa.

“Nephridia.—The third and fourth segments of the body are occupied by a conspicuous mass of nephridial tubules, which had a pinkish colour in the specimens dissected. This evidently corresponds to the ‘mucus-gland’ found in the other New Zealand species, A. multiporus. The nephridia throughout the rest of the body are regularly arranged, one pair to each segment; the apertures do not alternate in position, but are invariably placed in the neighbourhood of the lateral pair of setæ. There is no conspicuous muscular sac forming the extremity of the tube, as in nearly all the other species of the genus. The nephridia therefore are, on the whole, more like those of A. novœ-zealandiœ than of A. multiporus.

“Alimentary Tract.—The pharynx commences in the second segment, and extends back as far as the end of the fourth. The gizzard occupies the fifth segment. Its proper position can only be satisfactorily made out by longitudinal sections, which show that the septum dividing segments v. and vi. is attached to the posterior extremity of the gizzard: as, however, the next septum is attached quite close to the former, the growth of the gizzard has brought about an increase in the capacity of that section of the body-cavity belonging to the fifth segment, at the expense of segment vi. Calciferous glands were entirely absent, but the œsophagus was extremely vascular. The intestine is furnished with a typhlosole which resembles that of Deinodrilus. This structure— the typhlosole—has a characteristic form in, at any rate, three species of Acanthodrilus; in the present species it is a simple fold, projecting through about one-third of the lumen of the intestine. In A. multiporus it has about the same relative proportions, but is trifid at the extremity. In A. dissimilis the typhlosole has shrunk to the most insignificant dimensions.”

In the summary of his paper Mr. Beddard mentions the following most important facts described therein: “(1.) The independence of the vasa deferentia and atria in Acanthodrilus; the two vasa deferentia of each side unite just before their opening on the eighteenth segment. The atria (=‘prostates’) open separately upon the seventeenth and nineteenth segments. (2.) The occurrence of six pairs of setæ in each (setigerous) somite of Deinodrilus. (3.) The completely double dorsal blood-vessel of Acanthodrilus annectens and of Deinodrilus benhami. (4.) The enclosure of each half of the dorsal vessel of Deinodrilus in a separate cœlomic space.”

Acanthodrilus rosæ, Beddard. Quart. Jour. Mic. Sci., vol. xxx.

This species is not uncommon in the Ashburton district. In habits it is similar to A. novœ-zealandiœ in being more active than annectens, antarcticus, dissimilis, or multiporus, and it is clearly distinguishable from any of these species by its rich-brown colour. In fully-matured individuals the clitellum is well marked, and yellowish-white in colour. Like A. novœ-zealandiœ the species is able to secrete, and lubricate its body with, a clear slimy fluid, which probably acts as a distasteful deterrent to its enemies, and also to enable it to penetrate more easily into the soil. The slimy secretions of both species are scentless and almost tasteless, although I may say that I have experienced a very slight tendency to acridity in the fresh secretion of A. novœ-zealandiœ. The specific characters of A. rosœ are here given, as defined by Beddard:—

“While A. antarcticus might easily be confused, on a superficial view, with A. multiporus, the present species is by no means unlike A. novœ-zealandiœ or A. dissimilis. Indeed, the external characters of the spirit-preserved specimens hardly permit the species to be distinguished from one or other of the above-named; but the internal characters enable A. rosœ to be recognised as a perfectly distinct and well-marked species; there is no possibility of confounding it with either A. novœ-zealandiœ or A. dissimilis. The largest specimen measured about 8in. in length. The colour of the spiritpreserved specimen is a rich-brown, darker upon the clitellar segment, and paler ventrally. The prostomium completely divides the peristomial segment. The setæ are paired; the pairs are, at any rate in the posterior region of the body, equidistant; this region of the body is quadrangular in section, the setæ occupying the four angles. The clitellum occupies segments xiv.—xix. (inclusive), as in A. novœ-zealandiœ. The position of the atrial pores calls for no special remark, as they are identical in position and appearance with those of A. novœ-zealandiœ.

“With regard to the internal anatomy, there are two principal points of difference from A. novœ-zealandiœ: firstly, the entire absence of specially-thickened septa. I have dissected a tolerably large specimen, and compared it with a specimen of A. novœ-zealandiœ of about the same size; there was a very marked discrepancy in the relative thickness of some of the anterior septa; and this difference could not possibly be accounted for by the unequal size of the two individuals. The second anatomical difference between A. rosœ and A. novœ zealandiœ is in the form of the spermathecœ, which, as is

so common among earthworms, have the most varied relations to the septa of the segments containing them, though the situation of the external aperture does not vary at all. Each spermatheca consists of a large pouch with relatively thin walls; this communicates with the exterior by a short thickwalled muscular duct; this duct gives rise to a diverticulum, which terminates in an enlarged cæcal extremity, the surface of which is furrowed. The difference between the spermathecæ of this species and those of A. novœ-zealandiœ is that in the latter the diverticula are sessile.

“In A. rosœ the structure of the spermathecœ is quite the same as in A. dissimilis: in both these worms the epithelium of the diverticulum does not appear to be—originally—so different from that of the pouch, though it comes ultimately to present a strikingly different appearance. The pouch itself is lined with tall columnar cells; in the interior of these are formed spherical masses of secreted granules which seem to closely resemble similar products described by Goehlich in the spermathecæ of Lumbricus. The epithelium lining the pouch is slightly folded. The diverticulum of A. rosœ is, as I have already stated, composed of a relatively long tube with muscular walls, which terminate in a swollen, somewhat lobate, cæcal extremity; this latter has a structure quite like that of the diverticulum of A. dissimilis and of Neodrilus. The epithelium is much folded, so as to divide the cavity of the diverticulum; in places the columnar character of the cells can be recognised, but for the most part they are not clearly recognisable, for the reason that they have become largely converted into balls of a viscous-looking substance which does not stain. So far as I have been able to follow the formation of the colloid-looking masses, I am inclined to think that they are the product of a fusion between smaller droplets which appear in the interior of the cells. The secretion, when formed, does not seem to be evacuated into the interior of the numerous cæcal pouches which constitute the extremity of the diverticulum, as it is in the spermatheca itself, but to remain where it was formed. In nearly all the viscous drops were imbedded bundles of spermatozoa, which were always very distinct in my preparations, owing to the fact that they were deeply stained by the colouring reagents used (alum carmine and borax carmine). A superficial examination of such a section almost conveyed the idea that the spermatozoa were developed in the diverticulum, so close is their relation to the epithelium. There can be little doubt, however, that the function of these masses formed by the breaking-down of the epithelium is to retain the spermatozoa within the pouch until ready for transference to another individual. The spermatopores of Acanthodrilus are not known,

and we have no information whatever with regard to the process of fecundation in that genus. It seems likely on a priori grounds that they will prove to be different from those of Lumbricus, owing to the far greater complication of glandular appendages connected with the reproductive ducts.”

Acanthodrilus antarcticus, Beddard. Quart. Jour. Mic. Sci., vol. xxx.

In habits and colour this species closely resembles A. multiporus. Its smaller size distinguishes it from the larger form, and it is not so common. I find it inhabiting the edge of an old swamp on the south bank of the Ashburton River, and I have also collected a few specimens in other localities. The anatomy of the species is given in the following abstract of Beddard's valuable paper on “New Species of New Zealand Earthworms”:—

“The setœ are disposed in four series of pairs, but the two setœ of each pair are not close together as in A. novœ-zealan-diœ. Setæ 1 and 2 are closer together than 3 and 4; the distance between 2 and 3 is about equal to that between 3 and 4. The prostomium does not completely divide the first segment; it does in A. novœ-zealandiœ. The first dorsal pore is between segments v. and vi.; they are not visible upon the clitellum. The clitellum, which is distiguishable even in the spiritspecimen by its darker colour, occupies segments xiii. to xvii. The atrial pores are, as usual, situated upon the seventeenth and nineteenth segments on prominent papillæ. A longitudinal groove, as in other species, connects the two orifices of each side. The external characters ally this species rather with A. multiporus than with A. novœ-zealandiœ or A. dissimilis; the distribution of the setæ and the characters of the prostomium are much the same: it differs in the less extent of the clitellum, and in the fact that the papillæ upon which the atrial pores are borne are not so prominent as in A. multiporus; the prominent atrial papillæ are specially characteristic of A. multiporus and also of A. annectens. The internal anatomy of A. antarcticus shows numerous points of resemblance to A. multiporus, though there is no doubt as to its distinctness.

“Alimentary Tract.—The pharynx occupies the first four segments; there is a well-developed gizzard in segments vi. and vii.; in the fourteenth and fifteenth segments the walls of the œsophagus probably represent the calciferous glands of other earthworms; in A. multiporus these glands are found further back, in the seventeenth segment. I have studied the structure of these glands by transverse and longitudinal sections. It appears that they really represent two pairs of glands such as are found, for example, in A. dissimilis, but their apertures into the œsophagus are so large that the glands

present the appearance of being little more than glandular dilatations of the œsophagus itself; in transverse sections, however, the epithelium of the œsophagus can be here and there detected, and it is totally different from the epithelium of the glands; the cells are much more elongated, and are more deeply stained than the cells of the glands by the reagent used (alum carmine); both the glandular cells and the epithelial lining of the œsophagus are furnished with long cilia—a character which distinguishes the calciferous glands of this species from those of A. dissimilis, and from certain glands of other earthworms (e.g., Urochœta) which have been regarded as the homologues of the calciferous glands.

“Vascular System.—The dorsal vessel is like that of A. multiporus; it is completely double from end to end of the body; for the most part the two vessels are placed side by side, but they do not fuse at the points where they traverse the mesenteries; on the gizzard the two dorsal vessels come to be somewhat widely separated. The transverse vessels uniting the dorsal with the ventral vessel form large conspicuously-dilated ‘hearts’ in segments x.–xiii. (inclusive). In all the points A. antarcticus agrees closely with both A. multiporus and A. annectens.

“Septa.—The characters of the intersegmental septa appear to offer useful specific characters in this genus; in some species a certain number of the anterior septa are greatly thickened; the number of septa which are thus enlarged, and the degree in which their thickness is increased, differ, for instance, in the present species and in A. multiporus. In A. antarcticus the septa separating segments vii.–viii., viii.–ix., ix.–x., x.–xi., xi.–xii., are specially thickened, particularly the last four. In A. multiporus the same septa, with the addition of one in front and one behind, are thickened, but not so much as in A. antarcticus.

“Genital Organs.—The testes are two pairs of minute bodies in segments x. and xi.; each is attached to the anterior septum of its segment close to the junction of the septum with the body-wall; it is placed exactly opposite to the funnel of the vas deferens. The ovaries occupy a corresponding position in segment xiii., the funnel of the oviduct having a relation to them similar to that of the funnel of the vas deferens to the testis. The two pairs of atria are situated in the seventeenth and nineteenth segments respectively; each is a much-coiled glandular tube communicating with the exterior by means of a narrower tube with thick muscular walls. The structure of these organs presents, in fact, no differences from other species. Penial setœ are present on both the seventeenth and nineteenth segments, as in most other species of Acanthodrilus, but not in A. multiporus; the mature penial

important characters of P. bakeri, in which it seems to resemble the present species, and to differ markedly from other Perichœtœ. In any case, therefore, it seems to be desirable to draw the attention of zoologists to this earthworm, as it seems to connect the genus Perichœta with other forms. The most remarkable structural peculiarities of P. intermedia concern the excretory and reproductive organs. It is a moderately large species, being stout in proportion to its length; its general aspect is very different from that which is characteristic of Perichœta; the setæ are not at all conspicuous, and the worm has a smooth, somewhat glandular appearance. This seems to be due to the absence of a ridge in the middle of each segment for the implantation of the setæ. The buccal lobe does not divide the peristomial segment. The clitellum was not developed in either of my two specimens. The setœ form a nearly complete ring round each segment, only failing for a short space in the mid-dorsal and mid-ventral lines. There are no dorsal pores. In the neighbourhood of the male genital pores are a number of papillæ. The male genital pores are a pair of slit-like orifices on the eighteenth segment, on a line with the setæ, which are almost absent in the space between the two orifices, there being apparently only one seta on the inner side of the pore. The oviducal pores are paired, and upon the fourteenth segment; this is unusual, but is occasionally met with in the genus Perichœta. The common arrangement is a single median pore. The nephridiopores are quite obvious upon most of the segments, and lateral in position.

“Alimentary Canal.—The gizzard is situated in the fifth segment; it is very small, and the muscular walls not very thick. The œsophagus is furnished with separate calciferous glands in segments x. and xi. These glands are not, as is so often the case, connected with the lumen of the œsophagus by a narrow duct; they present the appearance of swellings of the œsophagus, and resemble very closely the calciferous glands of Microchœta (Beddard, Benham). Though probably formed as two-paired outgrowths of the œsophagus, no trace of a paired arrangement is visible in the adult worm. The nephridia are paired; the funnels, as is nearly always the case, open into the segment exterior to that which bears the external orifice. I reserve for the present details as to the structure of the nephridia.

“Genital Organs.—The sperm-sacs are in ix., x., xi., and xii. The vasa deferentia open into segments x. and xi.; the two vasa deferentia unite to form a single tube, the relations of which with the atrium I have not been able to make out with certainty. I believe, however, that it does not open on to the exterior independently of the atrium; there are no

conspicuous penial setæ, but it appeared to me that one or two of the setæ in the immediate neighbourhood of the genital pore were rather longer than the others. The ovary is in segment xiii., and the oviduct opens into the same segment; there is nothing unusual about either of these organs. The ovary, as in most earthworms, is not a compact organ, but is prolonged into numerous filiform processes. The egg-sacs (receptacula ovorum) are very conspicuous structures; they lie upon the posterior surface of the septum separating segments xiii. and xiv., and on either side of the intestine. These organs are larger than is generally the case, and have a racemose appearance; in both these points they present an interesting resemblance to sperm-sacs; furthermore, they contain numerous gregarines. In one specimen, the genital region of which I investigated by transverse sections, the structure of the egg-sacs was a little different from that of other earthworms which I have had the opportunity of studying. The walls are tolerably thick, and appear to be made up of fibres. Interspersed among them are nuclei which are extraordinarily numerous; the blood-supply was not very great, but this may be due to accidental causes. The presence of egg-sacs in Perichœta has been noted in but four species. In P. intermedia the egg-sacs were filled with mature ova, all of which were surrounded with a perfectly distinct follicular epithelium composed of flattened nucleated cells. In addition to this follicular epithelium—between which and the ovum is a distinct vitelline membrane—many of the ova were also furnished with a small number (four or five) of germinal cells attached to one pole. This is an interesting resemblance to certain of the lower Oligochœta, in the majority of which the ova are detached from the ovary, and fall into the egg-sacs in company with a number of germinal cells, which probably serve for the nutrition of the ovum. There are four pairs of spermathecœ, occupying segments v.–viii.; each is furnished with a single supplementary pouch of small size: this was conspicuous by reason of its yellow colour, and, as in P. sumatrana, was crowded with spermatozoa. The septum to which the egg-sacs are attached is one of the specially-thickened septa, of which there are six, dividing segments viii.–xv. The egg-sacs are attached close to the œsophagus, and where the œsophagus perforates the septum there is a space left, through which the egg-sac is prolonged, opening into the interior of the thirteenth segment, and coming into very close relations with the funnel of the oviduct; the passage of the ova into the egg-sac is facilitated by this, and by the fact that the two thick mesenteries which bound segment viii. are closely approximated, so that the actual cavity of the segment is much reduced. The part of the egg-sac nearest to its attachment forms a spacious cavity, undivided

cases ‘reserve setæ,’ more or less immature, and to the number of two, were present in addition to the fully-formed and functional setæ. The setæ are implanted so as to divide the circumference of the body into four areas; the distance, however, between the ventral pairs is less than that between the dorsal and ventral pair of one side, and the distance between the two dorsal pairs. The arrangement of the setæ, therefore, in P. smithii brings the genus nearer to the Lumbriculidœ, where there are four rows of pairs of setœ. Another point in which P. smithii differs from the other species of the genus is in the shape of the setæ. In both the other species the shaft, the portion implanted in the body-wall, is straight: in P. smithii this is not the case; the setæ are bent throughout, and have the shape so characteristic of the setæ of the Oligochœta.

“Absence of Genital and Penial Setœ.—It is important to put on record the fact that in the neighbourhood of the reproductive apertures there is no modification whatever of the setæ. It is not possible to state with absolute certainty that Phreoryctes has no genital setæ, but it is at least highly probable that this is the case. This, again, is a point which bears upon the affinities of the genus. Most Oligochœta show some modification of the setæ on the genital segments, but this is apparently not so with, e.g., the Lumbriculidœ, which family Phreoryctes resembles in other particulars.

“Clitellum.—In the majority of my specimens the clitellum was developed. The position of the clitellum in the genus has not been hitherto known, and, as this organ is of some little importance in the classification of Oligochœta, it is particularly desirable to have some information upon the point. The clitellar region was obvious, in all the specimens which had reached that degree of maturity, by its swollen, distended appearance and whitish colour. The swollen appearance and the white colour are, however, due not so much to the modification of the integument in this region of the body as to the mass of generative products, principally spermatozoa, which are developed in these segments, and cause them to be considerably distended. The comparatively slight increase of thickness in the epidermis of the clitellum, as compared with the epidermis over the general body-surface, is not sufficient to distinguish this part of the body when examined without the aid of a microscope. When the body is slit open, and the integument examined microscopically, the extent of the clitellum is quite obvious; it extends over three complete segments and the part of a fourth. The posterior boundary of the clitellum coincides with the furrow separating segments xiii.—xiv. Anteriorly the clitellum is not so sharply defined; it commences on segment x., at or near the setæ. The clitel-

lum of P. smithii therefore occupies three segments and a portion of a fourth, commencing on the tenth and ending at the posterior border of the thirteenth segment. It forms a complete girdle round these segments—i.e., there is no ventral space not invaded by the glandular modification of the integument. The clitellum therefore includes all the apertures of the generative ducts, which are thus in the strictest sense ‘intraclitellian.’

“Vascular System.—The vascular system of P. smithii consists, as in the other two species of the genus, of a dorsal and ventral trunk, which are united by transverse branches. The dorsal and ventral vessels are connected in each posterior segment by a transverse pair of trunks, which do not pass straight from the dorsal to the ventral vessel, but have a very sinuous course. The coils of these lateral vessels are not, however, so complicated as in the anterior segments, and their calibre is also less. The vessels, moreover, are not invested by a thick sheath of peritoneal cells like the anterior lateral trunks. The vascular trunks of these posterior segments are precisely like those of Phreoryctes filiformis, as described and figured by Vejdovsky. In P. menkeanus the lateral trunks are only connected with the ventral vessel; they arise from the latter, and pass round the circumference of the cœlom for a considerable distance, but do not join the dorsal vessel.

“Reproductive Organs.—The testes are, as stated before, two pairs, situated in segments x. and xi.; they are not, however, of a simple conical form in the fully-developed worm, but prolonged into several processes; the digitate shape is due to the rapid and unequal proliferation of the testicular cells. The genera Lumbricus and Allolobophora (among others) have been distinguished by the form of the testes, which have been figured as of conical form in the one, and digitate in the other: it is very possible that this difference does not really exist, but that it is merely due to the stage of development at which the organs have been studied; such a difference occurs, at any rate, in Phreoryctes.

“Vasa Deferentia.—There are two pairs of these ducts, which open independently of each other on to segments xi. and xii. The first pair do, indeed, open near to the ventral pair of setæ between these and the dorsal pair; but the second pair are a little different. The vas deferens of each side is much shorter, and opens well in front of the ventral pair of setæ of the twelfth segment, though behind the groove which separates this segment from the eleventh: that there is really this somewhat unexpected difference between the two pairs of vasa deferentia I have been able to prove by longitudinal sections, which are much better than transverse sections for demonstrating such a point. In preparation of the worm,

mounted entire in Canada balsam, some of the orifices of the sexual ducts were quite conspicuous. One of three such preparations which I have shows the external pore of the oviducts, and of the posterior pair of vasa deferentia: in all three cases the orifices are situated on a line with and in front of the ventral setæ; the oviducal pores are placed further forward than the male pore—in fact, on the intersegmental furrow.”

The following summary to Mr. Beddard's paper is given by that gentleman as specially characteristic of the genus Phreoryctes:—

“1. The body is extremely elongated, sometimes reaching a foot in length, while the diameter is very small.

“2. The prostomium is divided into two by a transverse furrow.

“3. The setæ are simple, not bifid; they are disposed in four rows of single setæ, or of pairs of setæ.

“4.^* There are no genital or penial setœ.

“5. * The clitellum occupies three to four segments from the tenth to the thirteenth; its epidermis is formed by a layer of glandular cells, differing from the epidermis of the general body-surface by their glandular character and greater length.

“6. The structure of the longitudinal muscles.

“7. * The nephridia commence in the sexually-mature worm in the sixteenth segment.

“8. There are two pairs of testes, in the tenth and eleventh segments.

“9. Two pairs of vasa deferentia opening into the exterior upon the eleventh and twelfth segments in front of the ventral setæ, and opening by wide, simple (not plicated) funnels into the tenth and eleventh segments.

“10. Two pairs of ovaries in segments xii. and xiii.

“11. Two pairs of oviducts opening into the exterior on segments xiii. and xiv., near to the lower line between these segments, and the one in front on a line with the ventral setæ. The oviducts open by wide simple funnels into the interior of segments xii. and xiii. The structure of these organs is exactly that of the vasa deferentia.

“12. Both series of the ducts have the distal region lined with a chitinous membrane indicating (?) their origin from an octodermic invagination.

“13. * The developing spermatozoa are contained in spermsacs, which occupy segments ix. to xiv. (about).

“14. * The ova, which are when adult of very large size,

This is frequently met with among terrestrial Oligochœta, where it appears to have an obvious relation to the density of the medium in which they live. Increased muscular power in the anterior segments is not so much needed by worms which swim in water, and is not developed. Pelodrilus, however, does not live in water, like most of its allies, but in marshy land; and its structure bears evidence of its mode of life, not only in the thick longitudinal muscular coat of the anterior segments, but also in the greatly-increased thickness of some of the anterior intersegmental septa. The epidermis consists of the usual glandular cells, between which lie tall interstitial cells. The circular muscular layer is not more than two fibres thick in the anterior thickened region of the body. In connection with the epidermis I may mention the presence of two sucker-like structures, which lie, one behind the other, in the middle ventral line of segment x. These bodies seem to be possibly organs of sense connected with the generative functions.

“Alimentary Canal.—This presents the characters that are usually met with in the lower Oligochœta,—that is, there is no gizzard, and no glands appended to the canal. The buccal cavity occupies the first segment of the body. Its walls consist of little else than a layer of somewhat flattened cells. The pharynx also occupies a single segment—the second. It is chiefly distinguished by the thickened epithelium, developed only on the dorsal side; which begins and ends abruptly. A few muscles attached to the pharynx connect it with the body-wall. The œsophagus is narrow, but the commencement of the intestine is hardly wider. The latter is distinguished by its epithelium being ciliated. The chloragogen cells commence in the fifth segment. It was Claperède who first noticed that the chloragogen layer covering the intestine was a fixed point often characteristic of the species.

“Nephridia.—The nephridia, instead of being, as is the rule in the aquatic Annelids, absent in the genital segments, are present in all the segments of the body commencing with the seventh, and excepting the eleventh and twelfth. There is hardly any development of peritoneal cells round the nephridia; certainly the large vesicular cells, which are so often found in the aquatic Oligochœta, are absent.

“Body-cavity.—The septa which separate the cœlom into a series of cavities corresponding to the external segments are replaced in the four anterior segments by irregularly-placed fibres and bundles of fibres passing between the alimentary tract and the parietes; after the fifth segment the regular septa begin. It is interesting to find that the first five of these are very thick, and consist of two distinct muscular coats, whose fibres run in opposite directions. The septa are

cup-shaped, with the concavity directed forwards, and in the segments which contain the sperm-sacs and ovisacs this concavity is much emphasized by the stretching of the septa caused by the growth of the sacs in question. As far as I am aware, Pelodrilus is the only instance of an Oligochæt which Claperède would undoubtedly have referred to his group of Limicolœ, where this increase in thickness of the anterior intersegmental septa is met with. It may very possibly have a relation to the habitat of the worm in soil, and not in the softer mud at the bottom of a lake or river, and in any case it shows that no importance can be attached to the presence of these thickened septa in earthworms as a character distinguishing them from the lower Oligochœta. In view, however, of other points in which Pelodrilus resembles the higher Oligochœta, this character perhaps gains an additional importance.

“Septal Glands.—The septal glands are found in segments v.–vii.: they form a series of paired structures lying on the anterior face of the cup-shaped septa which lie between these segments. I could not find any evidence of their possessing a central lumen such as has been described by various writers. In all my sections the septal glands were undoubtedly solid structures, though often furnished with a fibrous core. They have a glandular appearance, and are pear-shaped. The structure of these glands, in fact, is very much like that of the ‘capsulogenous’ glands in Perichœta. In Pelodrilus I must confess to having been unable to trace the ducts of the septal glands through the pharyngeal epithelium. They appeared to end at the bases of these cells. It is almost unnecessary to point out that there is every probability of the pharynx being in Pelodrilus of stomodæal origin.

“Testes.—There are two pairs of testes, placed in segments x. and xi., and attached to the anterior septa of their segments. They are of considerable size when fully developed, and branched at their free extremities. In the mature worm the testes are nearly always incomplete in number, owing, presumably, to the fact that the germinal cells of one or more of the gonads have been transferred to the interior of the spermsacs.

“Vasa Deferentia.—The vasa deferentia are remarkably long and greatly coiled. The vas deferens is for the most part extremely thin, though it widens out just before joining the funnel, and also for some little distance in front of the external orifice. In the extremely thin and much-coiled vasa deferentia, Pelodrilus differs from all the Oligochœta, to which it presents other points of affinity. The structure of the vasa deferentia is not in any way peculiar; they are, as is always the case, composed of a single layer of cubical cells,

and are covered by a delicate layer of peritoneum. The communication of the vasa deferentia with the exterior is effected in a way which is unique among the Oligochœta. There is no trace of an atrium—a structure which is present in all the Lumbriculidœe. The vasa deferentia open directly on to the exterior, as in Phreoryctes and the Lumbricidœ. The male apertures are situated within the clitellum, and are conspicuous when this region of the body is examined in a specimen mounted entire. I have been able to recognise two pairs of orifices placed upon the twelfth segment. In longitudinal sections two distinct male apertures are to be found on each side of the body, placed one in front of the other, and on a line with the oviducal pores, as well as with the apertures of the spermathecæ. The two male pores of each side of the body are very much nearer to each other than the posterior of the two is to the oviducal pore. It follows, therefore, that, while the posterior of the two funnels is connected with a vas deferens which opens upon the following segment, the anterior vas deferens traverses two segments before it communicates with the exterior. This is the only instance known to me of an Annelid which would obviously belong to Claperède's division of the Limicolœ, in which the aperture of the vas deferens is situated further behind its funnel than the following segment; and this genus forms a unique instance of the vasa deferentia of each side opening on to the same segment, but by separate orifices. In the position of the funnel and male orifices this genus appears to be intermediate between Phreoryctes on the one hand and Eisenia (= Tetragonurus) on the other. In Phreoryctes each vas deferens opens separately on the segment behind that which contains the funnel; in Pelodrilus the anterior male pore has receded until it has come to lie in the same segment with the posterior pore.

“Ovaries.—There are a single pair of ovaries in segment xii. Each is attached close to one side of the ventral nerve-cord. The ovary is of an oval, somewhat pear-shaped form; it is for the most part made up of small germinal cells, and contains one or two ova in advanced stages of development. The ova, however, do not undergo their entire development in the ovary; masses of cells consisting of developing ova are, apparently, from time to time broken off, and undergo their further development in the egg-sac. The fully-mature ova are laden with yolk-granules, and are of very large size; a single ovum will extend through two or three segments.

“Oviducts.—The two oviducts open on to the intersegmental groove xii./xiii. What strikes one about the oviducts of this and other ‘Limicolœ’ is the small size, as compared with the gigantic ova which have to find their way out of the body-cavity through them.

body is straight and of some thickness; the free portion is slightly curved, and tapers gradually towards its extremity. Each of these setæ was invariably accompanied by two reserve setæ of the same form, one on each side. In no instance did I observe more than a single mature seta belonging to each of the two dorsal series. On the other hand, the ventral setæ were as invariably paired. The setæ of the ventral series are of two kinds; a single set of each kind are found in every pair. In both cases the setæ approximate in shape to those of the Lumbriculidœ and of earthworms; the extremity is not bifid, and shows no traces of having been worn down. The imbedded portion of the setæ is nearly straight, but the free portion is much curved—more so than in the setæ of the two groups referred to. This, however, only applies to the larger of the two setæ in each pair; the smaller seta has a less-marked curvature. I could observe no difference in the setæ in the different regions of the body; but, as the worm was not fully mature, it does not follow that such differences may not be developed later. In every case the setæ protruded from the apices of well-marked papillæ. The prostomium is obtuse, ending in a wide truncated anterior margin. The clitellum was visible in neither of the two specimens. The male genital apertures are paired, and lie on segment xii., in front of the ventral setæ. The oviducal pores occupy a corresponding position in the interval between segments xii. and xiii. The spermathecal pores lie in front of the dorsal setæ of segment xiii.

“Integument.—The integument had the same structure throughout. In neither of the two specimens which I examined was the clitellum developed, nor was there the very least indication of the position of this organ, such as is sometimes afforded in immature Oligochœta. It is evident, therefore, that Phreodrilus, like some other genera, may reach a considerable degree of sexual maturity of the internal organs without a corresponding development of the clitellum.

“Nephridia.—These organs commence only in the fourteenth segment (in the worm with sexual organs); the whole organ is furnished with the large vesicular cells so commonly found attached to the nephridia of the lower Oligochœta. The funnel opens into the segment in front of that in which the organ lies; it is small, and is placed to the side of the nervecord.

“Alimentary Tract.—As no known genus of the aquatic Oligochœta possesses a gizzard,^* it is almost unnecessary to state that Phreodrilus, which would certainly have been in-

cluded by Claperède in his Oligochœta Limicolœ, has no trace of such a structure. The alimentary canal of Phreodrilus has in other respects the usual simple structure of the lower Oligochœta. It is also, as in the Naidomorpha and Enchytrœidœ, ciliated throughout, with the exception only of the buccal cavity. The cilia of the pharynx and œsophagus are shorter than those of the intestine, but not less obvious. The buccal cavity is distinguished by the short columnar cells by which it is lined. It is abruptly marked off from the pharynx, particularly on the dorsal side; the obvious demarcation between the two structures is not, however, due to a sudden change in the character of the cells, but to their very rapid increase in length; the dorsal wall of the pharynx is lined by very tall cells, which in the space of three or four cells change their character to the comparatively flattened epithelium of the buccal cavity. The posterior limits of the pharynx are not at all clearly marked; the epithelium very gradually decreases in height, and it is impossible to fix upon any point which might be termed the junction of the pharynx with the œsophagus. The calibre of the intestine is greater than that of the œsophagus, and its walls are in the same way highly vascular. The transition between œsophagus and intestine is not very abrupt; the intestine seems to commence in segment xiii.

“Vascular System.—In longitudinal sections of Phreodrilus two perfectly-separate vessels may be observed running along the dorsal wall of the œsophagus. Their course is fairly straight. The two vessels are different from each other in structure, and cannot therefore be confounded in sections where sometimes only one of the two was visible in a particular segment. The vessel, which is closely applied to the dorsal wall of the œsophagus, is extremely thin-walled, and completely filled with coagulated blood. It resembles in these particulars the ventral blood-vessel. In both vessels, particularly in the supra-intestinal, it is easy to see that the blood is a corpusculated fluid; here and there oval bodies, which have in every respect the appearance of the nuclei in the endothermal lining, may be seen imbedded in the coagulated yellow blood. There is little doubt that Lankester's description of corpuscles in the earthworm's blood will be extended to other—to perhaps all the groups of Oligochœta, in many of which they have been observed by Vejdovsky. Here and there the endothelium lining the blood-vessels—particularly at the points where they traverse the intersegmental septa—is thickened to form valve-like structures. These agglomerations of cells may be the localities where the blood-corpuscles take their origin through the rapid proliferation of the lining membrane, as Vejdovsky has suggested. The supra-intestinal

vessel is connected with the blood-supply of the intestines, and it gives off from the lower side numerous branches, which at once break up and form a plexus lying between the œsophageal or intestinal walls. The supra-intestinal vessel is also connected in the twelfth segment directly with the ventral vessel. This connection is effected by a pair of great coiled vessels, which I describe later as blood-glands. Further forward the supra-intestinal vessel appears to have no connection with the ventral vessel; there are, however, a number of perivisceral trunks, thin and coiled, which surround the œsophagus and communicate with the ventral trunk. These take their origin from the dorsal blood-vessel. We thus have in Phreodrilus, as in Lophochœta and Bothrioneuron, a double system of perivisceral trunks, one set connected with the dorsal and the other with the supra-intestinal vessel. As in Lophochœta, there is only one pair of vessels belonging to the latter set. It seems to me, however, to be far from certain that the dorsal vessel of Phreodrilus is the homologue of the dorsal vessel in Tubifex and some of the lower forms. The question then arises, To which of the two vessels of Phreodrilus does the dorsal vessel of Pelodrilus and other of the lower Oligochœta correspond? The relations of the single dorsal vessel, which is present in the posterior segments of Phreodrilus, to the intestinal, suggests that it is the equivalent of the single dorsal vessel of other Oligochœta: in this case the vessel which I have termed ‘dorsal vessel’ in the anterior segments will be unrepresented in these Oligochœta. There can, I think, be little doubt that the two dorsally-placel bloodvessels of Phreodrilus are the equivalents of the two in Perichœta, Acanthodrilus, and a large number of earthworms. In the simpler forms of Oligochœta, then, the dorsal vessel in most cases has disappeared, while the persistent supra-intestinal takes on its functions as well as its own.

“Testes.—The testes of Phreodrilus lie partly in segment x., but chiefly in segment xi. In longitudinal sections I have found a perfect continuity between the portions of the testes which lie in front of and behind this septum. There is, however, no doubt that in Phreodrilus the germinal tissue is perfectly continuous through the septum. At both extremities each testis is frayed out into irregularly-shaped processes, which contain the germinal cells in the most advanced stage of development. The body-cavity in the neighbourhood of the gonad is occupied by a quantity of developing and fully-developed spermatozoa. There was no trace of a sperm-sac, which is a nearly universal structure among the Oligochœta. As ripe spermatozoa were abundant in the body-cavity and in the circurmatrial sac, I think it probable that no sperm-sac other than the circumatrial space is ever developed.

“Vas Deferens.—Phreodrilus is furnished with only a single pair of vas deferens funnels, situated in segment xi. It is comparatively small, and markedly cup-shaped. The funnel is lined by a single layer of epithelial cells, which are furnished with particularly long cilia. The funnel on each side of the body is connected with the vas deferens, which is a narrow tube lined by comparatively few cells.

“Atria.—One remarkable point about the atrium of Phreodrilus is its great length; but, instead of extending through a large number of segments, as in Latroa, the entire atrium is contained in the twelfth segment. It is, however, coiled upon itself several times, and is thus able to be stowed away in one segment. The structure of the atrium is the same throughout. The epithelium of the whole atrium was thrown into folds. I could detect no trace of cilia anywhere; and, as the cilia of the vas deferens and other organs were beautifully preserved, I am disposed to think that the atrium of this genus is not ciliated during life. At the external pore the atrial epithelium passes without any break into the epidermis. There was no trace of a penis or any specialisation in the distal section of the atrium.

“Ovaries.—These gonads are paired, and arise from the intersegmental septum between segments xi.—xii. in a position corresponding to that of the testes; they lie therefore on the twelfth segment below the funnel of the vas deferens; but they do not also extend into the segment in front as the testes do. The ovaries are limited to the twelfth segment. I have been able to observe certain stages in the development of the ova which show a remarkable parallelism to the development of the spermatozoa. Many clumps of developing ova were to be seen lying in various parts of the cœlom of segment xii. I found others (not so many) in segment xi. among the developing spermatozoa. This may possibly be due to the presence of an additional pair of ovaries belonging to the eleventh segment, but I have no other evidence which points to such a conclusion. The further stages in the development of the ova are as follow: The central mass of protoplasm is always without a nucleus, but soon comes to be clearly separated from the cells surrounding it; it assumes a polygonal form. The surrounding cells, which form a complete investment for the central mass, lose their pear-shaped outline, and become angular when they are in contact with the neighbouring cells and with the central mass of protoplasm. The outer surface is rounded and convex.

“Oviduct.—The oviduct, as in the Lumbriculidœ and Tubificidœ, is very short, and consists of little more than the