Art. XLIII.—Parasitic Copepoda of New Zealand, with Descriptions of New Species.

By Geo. M. Thomson, F.L.S.

The material available for my purpose has been derived from various sources. Several specimens have been secured by myself, chiefly on fishes bought for household use. A few were obtained during a whaling cruise by the captain of the barque “Splendid”; unfortunately there is no record with these to show from what host the specimens were taken. Mr. A. Hamilton has very kindly sent me, from time to time, specimens taken from various fishes caught at Napier. Lastly, Professor Parker placed at my disposal the material accumulated in the Otago Museum by himself and Professor Hutton.

The only species hitherto described from New Zealand seas are five in number, and belong to as many distinct genera. It is rather remarkable that Heller, during the stay of the “Novara” in Auckland, should only have obtained three species, when it is considered how much attention he paid to this order. The forms now recorded and described bring up the number of species to 24, and of genera to 16, and include representatives of all five families of parasitic Copepoda. It is evident that these represent only a small proportion of the species which may be looked for in our seas. No doubt many more species will be discovered as the habits and life-histories of the fishes of the colony are more closely investigated. The present contribution is a mere starting-point.

Fam. Caligidæ.

The legs of the fourth pair are 1-branched. Branch apparently 2-jointed, with the second joint bent nearly at right angles to the first. On magnifying it, however, more strongly, this terminal joint is itself seen to be 3-jointed: the first and second of these smaller joints each end in a spine on the outer margin, while the last bears 3 spines at the extremity. All three joints are fringed on their outer margin by a comb-like row of fine teeth. Perhaps this 3-jointed part is really the branch, the preceding segment being the elongated basal joint. At any rate, in figures of numerous species given by Kroyer this character is very persistent.

The caudal lamellœ are very long and slender, many times longer than they are broad. Their anterior part, for over a third of their length, is much broader than the posterior two-thirds. Each is furnished with several short spines, especially near the extremity. The last abdominal segment also bears two spines on the median line, which mark the position of the anus.

The total length of the animal, to the extremity of the caudal lamellæ, is 12–13mm.

Hab. Found, along with Penella, on a sword-fish, Histiophorus herschelii. (Otago Museum.)

Genus Nogagus, Leach.

1. Nogagus elongatus, Heller (“Reise der ‘Novara:’ Crustacea,” vol. ii., p. 206; pl. xx., fig. 5).

This species, which is fully described and figured in detail by Heller in the report of the Crustacea collected during the voyage of the Austrian frigate “Novara,” is probably, as he suggests, the male of Pandarus dentatus, having been taken along with that species from a shark caught at Auckland. Indeed, it is almost certain that the genus Nogagus consists only of the males of the various forms, of which the females are described under the generic names of Pandarus, Echthrogaleus, &c.

2. Nogagus validus, Dana (?).

This species is recorded by Dana as taken from a shark, north-east of New Zealand. The following is the brief description given:—

“Carapace a little oblong, oval; second segment with the sides prolonged backwards, third and fourth transverse, sub-equal, half as wide as carapace. Feet of second pair very short, cheliform, immovable; finger short, truncate, movable finger obtuse. Abdomen 2-jointed, anterior segment sub-quadrate. Posterior angles a little prominent, second segment short, transverse, the angles obliquely truncate. Caudal

stylets rather large, lamellar or little oblong; setæ three, plumose.”

It is impossible from such a description to recognize the species referred to. I regret also, in absence of Dana's work, that I am unable to give exact references of this species. The same remark applies to Pandarus brevicaudis and Specilligus curticaudis, referred to further on.

Genus Dinematura, Burmeister (Dinemoura, Latreille).

1. Dinematura affinis, M.-Edw. (“Hist. Nat. de Crustacées,” vol. iii., p. 465; pl. 38, figs. 15–18).

This species is briefly described by M.-Edwards as follows:—

“Species extremely like the preceding (D. alata), but having the posterior margin of the elytroid plates sinuous, the terminal lobes of the thorax somewhat narrowed and without the horny tooth at the end, and the abdominal appendages of the female large, oval, as long as the abdomen itself, but not exceeding the thorax. From New Zealand seas.”

I have not met with this species, which is figured by M.-Edwards, and is very different in appearance from the following three species described by me.

2. Dinematura hamiltoni, n. sp. Plate XXV., fig.1, a-j.

Male.—Whole body somewhat elevated dorsally. Cephalothorax rather square in front, nearly half as long as body, a little broader than long, rounded behind and ending in rather obtuse angles. Frontal lamina extending across about two-thirds of the cephalothorax. Penultimate segment of thorax short, with rounded lateral lobes. Last thoracic segment nearly three times as long as broad, with wide lateral wings. Genital segment short. Abdomen nearly square, only one joint apparent from above. Caudal lamellæ elongate. Fourth pair of feet 2-branched, each branch 2-jointed, terminal joint furnished with short, simple, soft spines.

Length of body, 9mm.

Female.—Whole body rather flattened. Cephalothorax two-thirds as long as body. Dorsal lamellæ of penultimate thoracic segment only two-thirds as long as hind portion of body; ultimate thoracic segment relatively shorter than in male. Fourth pair of feet 2-branched, each branch consisting of two rather large rounded lamellæ.

Length of body, 12–15mm.; length of oviferous tubes, 30–35mm.

The antennœ of the first pair are normally formed, the 1st broad flat joint being furnished with numerous stout fringed spines; the 2nd joint ends in several smaller spines and one longish seta. The antennœ of the second pair are apparently

very distinctly separated from the front portion by a narrow constriction between the 2nd and 3rd thoracic segments. Frontal lamina distinct, extending across more than half the front of the carapace. The dorsal lamellæ of the penultimate thoracic segment are square-shaped in front and rounded behind. Under them the dorsal lamellæ of the last thoracic segment project to twice their length on their outer margins, the inner being much shorter. The abdominal segments also bear rounded lamellæ, which are greatly developed and project over the bases of the caudal lamellæ. The hind part of the body is considerably inflated below. The abdomen is very short, and nearly square in shape. Caudal lamellæ very similar in appearance to those of D. hamiltoni.

Colour, nearly white. Length, 20–22mm.; length of oviferous tubes, about 50mm.

Both pairs of antennœ have a close resemblance to the same organs in the preceding species. The foot-jaws are very similar to those of D. hamiltoni, the terminal portion of the 2nd joint being however more contracted, and the secondary spine jointed on to a short pedicel as in D. neo-zealanica. The feet are very similar in the number of joints, spines, and setæ to those of the first-named species, differing only in the shape of the joints. In the first pair the 1st joint of the outer branch is obliquely pyriform, and is marked on its outer margin by three rudimentary division-lines. In the second pair the 1st joint of the outer branch ends in a spine on its outer margin. Those of the third pair exactly resemble those of D. hamiltoni; while in the fourth pair the only difference lies in the form of the lamellæ, which in this species are long and narrow, and bear 1 minute spine on the inner margin of the inner branch, and 5 on the outer margin of the outer branch.

Hab. Numerous specimens (of females only) were taken from the ventral surface of the tail of a white shark—Carcharodon rondeletii,—and are preserved in the Otago Museum.

This species is very nearly allied to, if not identical with, D. lamnœ, Johnston; but the description and figure of that species in Baird's “British Entomostraca,” p. 206 (the only accessible one to me), is imperfect and insufficient.

Genus Echthrogaleus, Steenstrup and Lütken.

1. Echthrogaleus braccatus (“Reise der ‘Novara:’ Zool.,” vol. ii., p. 197; pl. xx., fig. 3).

Dinematura braccata, Dana (“U.S. Expl. Exped.: Crust.,” vol. xi., p. 1370; pl. 95, fig. 4).

The female of this species was originally described by Dana. In “The Voyage of the ‘Novara’” Heller describes and

fully figures the male. Both sexes were taken by Heller off an undetermined species of shark caught at Auckland. I have not met with this species.

Genus Cecrops, Leach.

1. Cecrops latreillii, Leach. Pl. XXVI., fig. 3, a-f.

This well-marked and well-known form appears to be the only species of the genus. M.-Edwards (“Hist. Nat. Crust.,” vol. iii., p. 474) records it as being found on the branchiæ of the tunny (sur les branchies du thon), but, with this exception, which may have been stated in error, it is invariably found as a parasite on sun-fishes of various species. Thus round the English coasts it is frequently taken on the gills of Orthagoriscus molœ (Baird: “Brit. Entomostraca,” p. 293). It is also recorded from the same species taken on the east coast of the United States. On the Pacific coast of the States it occurs on the gills of Diodon.

The body of this animal is about an inch long, and is thick and short. The carapace bears two rounded prolongations in front, which represent the frontal lamellæ of the preceding genus, and which in this species are rather closely anchylosed to the cephalothorax. The penultimate thoracic segment bears a dorsal shield notched at the posterior margin, which corresponds to the dorsal lamellæ in Dinematura. The last segment of the thorax bears a very large dorsal shield, deeply notched on the hind margin, and which extends beyond and completely covers the abdomen. Seen from the underside the abdomen is dilated and 2-lobed behind, and is covered in front by the greatly-enlarged bases of the fourth pair of feet. The first antennœ are small, and are produced at the angles of the frontal lamellæ. The second antennœ are powerfully developed, and end in strongly-curved brown horny hooks. It is by means of these organs and the powerful hooks of the second foot-jaws that the animals attach themselves to their hosts. The oral proboscis is relatively very short, as the animal appears to bury itself rather deeply in the tissues of its host. The feet are small, and bear either short spines or setæ; but the latter, though often finely serrated along their edges, never bear the feather-like fringes of the same organs in Dinematura. In the first three pairs both branches are 2-jointed. They do not end in hooks as stated by M.-Edwards, but in each case the short inner branch bears 3 setæ and a few (except in the first pair, which has none) short spines on the terminal joint. In the first pair the outer branch ends in 3 setæ and 4 spines; in the second pair the 1st joint ends in a powerful curved spine, while the 2nd bears several marginal setæ and small spines; in the third pair it ends in 2 (or 3) setæ. In the fourth pair the basal joint is developed

into a broad flat plate, bearing a very small 1-jointed branch near its outer edge. Inside of this, however, is a very distinct pointed lobe not clearly disarticulated from the basal lobe, which probably represents the imperfectly-developed inner branch of this pair of feet. The caudal lamellæ are extremely small and inconspicuous. The oviferous tubes are hidden in a remarkable manner. Instead of projecting in the form of long filaments, as is the case in most animals of this class, they are looped up into a dense mass, which lies between the abdomen and the dorsal buckler on each side.

Hab. Several specimens were obtained from the mouth of a sun-fish (Orthagoriscus molœ), which was taken in Otago Harbour. (Otago Museum.)

Genus Pandarus, Leach.

1. Pandarus dentatus, M.-Edwards (“Hist. Nat. de Crust.,” vol. iii., p. 469; pl. 38, fig. 19).

This species, originally recorded as taken near Tongatabou, is briefly described by M.-Edwards as follows:—

“Species closely allied to the preceding [i.e., P. vulgaris], but having the posterior margin of the carapace nearly straight and strongly toothed in the middle, and the dorsal lamellæ of the first segment of the thorax more rounded and shorter, not quite reaching to the middle of the penultimate thoracic shield; last segment of the thorax and the abdomen as in the preceding species.”

Heller (“Reise der ‘Novara’: Zool.,” vol. ii., p. 206) records having taken this species on a shark in Auckland. I have not met with it.

2. Pandarus armatus, Heller. Plate XXVII., fig. 1, a-f. (“Reise der ‘Novara’: Zool.,” vol. ii., p. 202; pl. xix., fig. 4.)

This species was described and figured by Heller from female specimens taken from a dog-fish (Scyllium africanum), from the Cape of Good Hope. The following is the brief specific diagnosis given by him:—

“Cephalothorax shorter than the rest of the body, somewhat narrow in front, slightly excavated behind, with short angles, posterior margin armed with 10 acute teeth; second segment with elongate-oval wings, 4-toothed behind; two following segments with acute median tubercles placed in front of the incision. Genital segment sub-quadrate, narrower behind, with posterior angles acute, tail oval, styles twice as long. Length of body = 8mm.”

The detailed description given by Heller is very full and fairly accurate, as are the drawings of those parts figured. The following are points in which my specimens either differ from Heller's, or which he has not described:—

Fam. Dichelesthina.

The first foot-jaws are of remarkable shape, and I have figured one of them. They are 3-jointed; the basal joint is stout and strong; the 2nd joint is elongated, flattened, and flanged on the inner side, and produced at the distal end into a pointed knob, round the extremity is a line of short spines surrounding it like a collar; the last joint is in the form of a round knob obliquely striated in a longitudinal direction, and having two lines of short spines which converge at its extremity. I cannot suggest the origin of this remarkable development, or its present use.

Hab. Numerous specimens taken from the upper jaw of a porbeagle shark—Lamna cornubica (Otago Museum). Also a number from the same kind of shark taken at Napier by A. Hamilton. According to Gould this species has been taken on the mackerel-shark—Lamna punctata—on the coast of Massachusetts, U.S.A.

Genus Lernanthropus, Blainville.

The animals of this genus are chiefly remarkable for the abnormal development of the third and especially of the fourth pair of thoracic feet, which are produced into the form of cylindrical or lamellate appendages under the body. The first and second pairs are very small. The anterior antennæ are very small, while the second pair are developed into hooked claws by which the animals attach themselves to their host.

Owing to the very varying extent to which the parts of the thorax are developed, there is great diversity of form among the different species.

1. Lernanthropus percis, n. sp. Plate XXVII., fig. 2, a-j.

Female.—The whole body of this species is about one and a half times as long as it is broad. Seen from above, the head is somewhat distinctly separated from the thorax, and is about subquadrate in form: its lateral margins are slightly dilated into two rounded lobes. The thoracic portion is broadly winged, the first segment showing a shoulder-like protuberance on each side, and the second being produced backwards into acute angles. The dorsal shield is about as broad as the thorax, about half as long as the whole body, rounded behind, and with a slight notch in the middle of the posterior margin.

Seen from below, two-thirds of the lower surface is covered by the large lamellæ of the third pair of legs, which do not, however, reach quite to the extremity of the dorsal shield, but leave exposed the folded-up ends of the oviferous tubes. Genital segment very short. Abdomen short, thick, rounded, and fleshy, very indistinctly 2-jointed (?), with a small notch

and two minute anal papillæ on the posterior margin. Caudal lamellæ very small, 2-(?)jointed, with two minute setæ at the extremity.

Anterior antennæ not seen. Posterior pair in the form of powerful hooked claws, by which the animal attaches itself to its host; these are 2-jointed, the basal joint being thick and powerful, while the shorter and more curved terminal joint bears a strong tooth on the middle of its inner surface, and behind it two or three rugosities.

First foot-jaws small and not very powerfully developed; the rather slender terminal joint ends in a feebly-chelate manner in two claws, the larger (and outer) of which is finely serrated along its outer margin. The second foot-jaws are strongly developed.

First pair of legs not seen. The second pair are very small, the minute outer branch being free and obliquely oblong, while the inner, which is in the form of a curved lobe, is anchylosed to the horny basal joint. The third pair are developed into large lamellar plates, the outer of which are broadly oblong, and rounded at their extremity, and have the narrower inner plates standing at right-angles against them. The fourth pair are produced in the form of two elongated and curved fleshy lobes, which are shorter than, and are completely hidden by, the lamellæ of the third pair.

Oviferous tubes rather longer than the dorsal shield, but lying slightly folded within its margin.

Length, 4–5mm.; colour, dark-brown.

Hab. A single (female) specimen was found by me on the gills of a blue cod (Percis colias).

This species is nearer to L. scribœ, Kroyer, in general form than to any other of the many oddly-shaped species of this genus, but differs entirely from it in most of the details of its structure. It is a very distinct form.

Genus Philichthys, Steenstrup.

1. Philichthys xiphiœ, Stp. Plate XXVIII., fig. 1.

I have several female specimens of this remarkable parasite, which were taken from the skull of a sword-fish (Xiphias gladius). Unfortunately, I do not know whether the specimen was taken near Dunedin, or from what part of the coast.

The male of this species, according to Bergsoe, is a long, narrow, Cyclops-like copepod, apparently free-swimming in its habits. The female, on the other hand, lives in the bones of the skull of the sword-fish, producing pit-like cavities in the bone-tissue. Not only is the body very numerously segmented, but the segments bear sac-like appendages whose analogies are not easily made out. The oral proboscis—so

Fam. Lernæodea.

about 18mm. long and 5mm. broad, and is very thickly fringed on both sides with numerous setiform processes. The oviferous tubes barely reach to the extremity of the abdomen, and are very slender and thread-like.

No males were seen.

The average total length of the specimens was about 90mm. (nearly 4in.).

Hab. Found on a sword-fish—Histiophorus herschelii. (Otago Museum.)

Genus Lernea, Linnæus.

M.-Edwards, and Baird after him, give the characters of the animals comprising this genus as follows:—

Body more or less twisted, and outré in appearance, destitute of rudimentary feet. Head furnished with horn-shaped appendages, which are irregularly branched. Ovarian tubes twisted together into rounded masses and placed under the posterior portion of the body. Abdomen large and distorted.

The description is incorrect as far as the appendages are concerned, as all four pairs of thoracic feet are present, although in a somewhat rudimentary condition.

1. Lernea lotellœ, n. sp. Plate XXVIII., figs. 3 and 3a.

In general appearance this species somewhat resembles L. branchialis, but the three cephalic arms are quite simple, and not branched as in that species. The head is small and rounded, each of the three simple arms below it extending to a length of about 4mm. The neck is long and rather narrow, gradually widening below, the lower portion of this segment being greatly dilated and bent completely on itself. At the extremity of this segment the oviferous tubes arise. These are closely coiled up into two masses or rolls, each about 6mm. or 7mm. long. The posterior end of the body is separated distinctly into an oblong abdomen. There is considerable diversity of form in the posterior part of the body, both in the extent to which it is dilated and the amount of curvature exhibited. The whole of this hind portion is more or less covered with a filamentous growth, part of which appears to consist of natural hair-like processes, but which is mainly formed of masses of filamentous Algœ and of sertularians. The front part of the body is very hard and horny, but the hinder part is much softer and leathery in consistence. It is probable that as these parasites are attached by the hard head, and have the softer posterior portion projecting on the outside of the fish which they infest, the growth referred to is of the nature of a protective covering, resembling in this respect some of the rather soft-bodied crabs (Paramitharax) which are similarly protected.

Fam. Chondracanthina.

least—several small Cirripedes and Serpulœ. The bunches of coralline-like appendages at the posterior margin of the genital segment are irregular in form, and equal it in length. The oviferous tubes are thin and nearly straight, or at most only slightly curved, and are about 60mm. long.

The whole length of the animal (exclusive of the oviferous tubes) is about 70mm.

Hab. Taken from the abdomen of a ling (Genypterus blacodes), in the tissues of which the whole soft front part of the body was imbedded.

Genus Chondracanthus, De la Roche.

The males of this genus are very minute, and are found attached under the posterior extremity of the thorax of the females. The body is more or less pyriform in shape, having a very large head and an articulated thorax. They are also provided with very large hooks (posterior antennæ) by which they remain attached to the females.

Females having the body of more or less bizarre form, and furnished with tubercles or lobed processes. Head generally indistinctly separated from the thorax and furnished with two pairs of antennæ. Of these, the first pair are usually short, and 1-(3)-jointed, while the second pair are in the form of hooked claws. The mouth is situated rather far back, and is furnished on each side with a small hooked maxilla. The foot-jaws are small, and end in hooked claws. Two pairs of thoracic feet are developed in the form of bifurcate lobes. The genital segment is usually produced backwards in the form of two lobe-like processes: between these arise the stout oviferous tubes. Between them projects a minute tubercle, representing the rudimentary thorax.

1. Chondracanthus chilomycteri, n. sp. Plate XXVIII., fig. 5, a-d.

Body rather stout, nearly three times as long as broad. Head small and not distinctly separated from thorax. Thorax divided into two rather distinct parts, of which the anterior is only half as wide as the posterior: the former is elongated and bears on each side two rounded protuberances which project laterally to a small extent: the posterior portion on the other hand is sub-quadrate in form, and bears two rounded protuberances, which project on its ventral face; the posterior extremity on each side is produced backwards to an obtuse lobe. The antennæ, which are broadly falcate in form, are rather closely approximated at their base, and do not reach to the margin of the head on each side. The first pair of thoracic legs are very small, and exhibit distinct segmentation; the second pair are very much larger, and consist only

Fam. Lernæopodidæ.

Explanation of Plates.

Plate XXVI.

Fig. 1. Dinematura neo-zealanica, female: a, foot of 1st pair, × 23; b, foot of 2nd pair, × 23; c, foot of 4th pair (male), × 23; d, abdomen (fem.) from under-side, × 8.

Fig. 2. Dinematura carcharodonti, female, seen from above, × 3: a, 1st foot-jaw, × 8; b, foot of 1st pair, × 23; c, foot of 2nd pair, × 8; d, foot of 4th pair, × 8.

Fig. 3. Cecrops latreillii, female, × 2: a, dorsal aspect; b, ventral aspect; c, foot of 1st pair, × 23; d, foot of 2nd pair, × 23; c, foot of 3rd pair, × 23; f, foot of 4th pair, × 8.

Plate XXVII.

Fig. 1. Pandarus armatus: a, female, dorsal aspect, × 4; b, female, ventral aspect, × 4; c, male, dorsal aspect, × 6; d, foot of 1st pair, × 40; e, foot of 2nd pair, × 40; f, foot of 4th pair, male, × 23.

Fig. 2. Lernanthropus lotellœ, female: a, animal seen from above, × 7; b, ventral aspect, × 7; c, posterior antennæ from below, × 26; d, 1st foot-jaws, × 26; e, extremity, × 80; f, 2nd foot-jaws, × 26; g, leg of 2nd pair, × 20; h, leg of 3rd pair (from the inside), × 13; i, under-side of thoracic shield with lamellæ of the 3rd pair of legs removed, showing (l) 4th pair of legs, (ab) abdomen and (ov) oviferous tubes, × 13; j, abdomen, × 20.

Fig. 3. Anthosoma crassum: 1st foot-jaw, × 20.

Plate XXVIII.

Fig. 1. Philichthys xiphiœ, female, seen from above, × 2.

Fig. 2. Penella histiophori, female, nat. size.

Fig. 3. Lernea lotellœ, female, × 2: a, the same species, but a somewhat different form.

Fig. 4. Lesteira kroyeri, female, nat. size: a, head of same seen from the front.

Fig. 5. Chondracanthus chilomycteri, female, × 5: a, anterior antennæ, × 26; b, posterior antennæ, × 26; c, leg of 1st pair, × 26; d, leg of 2nd pair, × 26.

Fig. 6. Chondracanthus genypteri, female, × 4: a, same in lateral aspect, × 4.

Fig. 7. Chondracanthus lotellœ, female, × 3: a, same in lateral aspect, × 3.

Fig. 8. Brachiella parkeri, female, nat. size: a, mouth-organs, × 26 (r, rostrum; an, antennæ; p, maxillary palpi); b, conical protuberances representing first foot-jaws.

Fig. 9. Lernœopoda musteli, female, × 2: a, mouth-organs, × 26.

Fig. 10. Lepeophtheirus huttoni: a, leg of 1st pair, × 26; b, extremity of last joint of same, × 56; c, leg of 4th pair, × 26.

Plate XXIX.

Fig. 1. Lepeophtheirus huttoni: a, male, dorsal aspect, × 7; b, female, ventral aspect, × 7; c, antenna of 1st pair, × 26; d, antenna of 2nd pair, × 26; e, oral proboscis, × 56; f, extremity of mandibles, × 26; g, foot-jaw of 1st pair; h, foot-jaw of 2nd pair; i, sternal fork, × 26; j, foot of 2nd pair, × 26; k, foot of 3rd pair; l, lamella of last thoracic segment, × 26; m, abdomen, × 26.