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DESORPTION 4 AND. FIGURES OF ALL THE SPECIES

@. O. SARS.

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AMPHIPODA,

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tweet AN ACCOUNT

—OOt.

OF THE

(FRUSTACEA

OF

NORWAY,

WITH SHORT DESCRIPTIONS AND -FIGURES OF ALL THE SPECIES

BY

G OF SARS

PROFESSOR AT THE UNIVERSITY OF CHRISTIANIA

Vol I. Ware

A Miia POW

(TEXT.)

CHRISTIANIA AND COPENHAGEN ALB. CAMMMERMEWYERS FORLAG

(LARS SWANSTR@OM

1895

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PREFACE.

In presenting to the scientific world the 1st Volume of the great work on Norwegian Crustacea, which I have entered upon, I wish to make the following observations about the plan of the work in general, and especi- ally that of the present Volume.

. The author, who during a long series of years has been engaged by the government to make investigations about the sea-fisheries of Norway, and for this purpose has made numerous journeys of research along the whole Norwegian coast, from the Christianiafjord to Vadso, has thereby had an unusually convenient opportunity for at the same time studying the rich marine invertebrate fauna occurring along that extensive coast, and has especially made himself familiar with the several groups of Crustacea, which had long before been his special study. A very large amount of zoological material has thus from time to time been brought together from many different localities, and among this material have been found numerous interesting forms new to science. Most of the new Crustacea have been briefly characterised by the author in several papers, chiefly published in the Transactions of the Scientific Society of Christiania, and a few groups, for instance the Myside, have also been more fully treated of in separate treatises. It has, however,

appeared to the author very desirable, that a full account of the rich carci- ~

nological fauna of Norway should be given, like that of the British Crustacea long ago published by several distinguished carcilogists, both because such faunistic works have on the whole shown themselves to be extremely useful, and because the fauna of Norway, as is well known, belongs to two distinct zoological regions, the boreal and arctic, and thus exhibits characteristic differ- ences from that of the British Isles. Indeed, the author has long felt it as a veritable duty, by entering upon a such work, to utilise his long experience for the benefit of future carcinologists. But the great expenses connected with the publication of such an extensive work in the usual manner, as publication from the University, have hitherto prevented him from realizing his plan, and it is only some few years since the idea struck him to get the work published

a

VI

in the mode here adopted. By reducing the expenses of publication as far as possible, and inviting to a general subscription, I supposed indeed that the publication of the work could be carried on by one of our publishing firms, without any real pecuniary loss, and by this means I have now the satisfaction of seeing the Ist Volume of my work accomplished. I cannot of course expect to be enabled during the remainder of my life’ to bring to a conclusion a work of such an extent as that now entered upon, comprising, as it does, the whole rich carcinological fauna of Norway, but I venture to hope that my health and working power will at least suffice for accomplishing a part of this formidable work. If the volume now published should succeed in, gaining the interest of Norwegian and foreign zoologists, and the anticipation entertained in beginning the work should thus be confirmed, it is my intention immediately to enter upon the publication of the 2nd Volume, treating of the next order, the Isopoda.

As to the Volume now accomplished, it has been wholly devoted to the extensive order of the Amphipoda, one of the most difficult of the Crus- tacean groups. The chief earlier investigation of the Norwegian Amphipoda is due to the late Dr. Axel Boeck, who at first published a brief account in Latin, and subsequently began the elaboration of his well-known great work, containing full descriptions of the species, and accompanied by numerous litho- graphic plates. Unfortunately he himself only published a comparatively small part of this work, the remainding, far greater part being published after his lamented death by his brother, Dr. Hakon Boeck, who was not originally a zoologist, but yet endeavoured to arrange the scattered, posthumous manuscript notes and drawings for the completion of the work. Although the great skill, with which this very difficult undertaking was accomplished, deserves the highest admiration, it was of course unavoidable, that several grave errors were incorporated in the work, which otherwise should have been eliminated. As moreover, in order to get room on the plates for the numerous figures, a most regrettable reduction in size of the original drawings was effected, and some of the figures also wrongly numbered, several of the species iad in some cases become almost unrecognizable. For these reasons the work of Boeck, though enriching the fauna with an immense number of new and interesting forms, could not be used without the greatest precaution and critical judgement, and rendered in fact the study of the Norwegian Amphipoda extremely difficult and troublesome. Notwithstanding this, some parts of the Amphipodous fauna were subsequently treated of in detail by Mr. Schneider, and a most valuable account of the arctic species of the family Oediceride, accompanied by some very good and sufficiently large detail-figures, has been given by that distinguished zoologist. But otherwise the knowledge of the

VII

Norwegian Amphipoda was still restricted to Boeck’s work, the use of which was, as above stated, connected with very much difficulty. Under such circumstances, I thought it right in the first instance to enter upon a total revision of this order, hoping thereby to supply the above-mentioned wants in Boeck’s work. To this end, I have gone over the vast collection of Amphi- poda made by Boeck, and especially most carefully examined the several type specimens in the collection, whereby several difficult. questions about the right identification of the Boeckian species have been finally settled. Nearly all the species described in the said work have been subsequently found by myself, and in most cases examined in the living state, and numerous additional species have been procured, increasing the number of Norwegian forms to about 400 in all.

i The aim of the present Volume is chiefly to facilitate the determina- tion of the northern Amphipoda. This, I believe, may be best attained, not only by giving good and concise diagnoses of the species, but especially by supplying figures, true to nature, and of sufficient size and clearness, both of the entire animal and of the most characteristic anatomical details. The lack of good figures has indeed hitherto made the study of this interesting order of Crustacea very difficult and, in many cases, has caused sad confusion ir the synonymy. Very great care has therefore been paid to the preparatior of the plates accompanying this Volume. They have been all drawn by the author himself, by the authographic method applied by him very successful!) during a series of years, and the habitus-figures have, in nearly every case been copied from carefully executed, coloured drawings made by the author from living specimens, thus showing the mode of pigmentation characteristic to each species. In every generic type the structure of the oral parts has been carefully examined, and figures of the same given on a greatly enlarged scale, as the classification of the Amphipoda ought chiefly to be based upon this character.

As to the systematical arrangement of the Amphipoda, I have only made some few changes in the system adopted by Boeck. It is, however, most probable, that a somewhat altered arrangement may be found convenient in future, as some of the families are far from being well defined.

In the Appendix to the volume some additions and corrections have been given, and some new species described and figured.

During the elaboration of the work, I have had very important assistance in the excellent Report of the «Challenger» Amphipoda by the Rev. Mr. Stebbing the very complete and elaborated survey of the literature given in that Report having especially been most invaluable to me.

I regret not having had an opportunity of consulting the recently

vin

published work of Delle Valle on the Amphipoda of the gulf of Naples. It is most likely that some interesting statements about the geographical distri- bution of the northern species are to be drawn from this work.

For the exact identification and comparison of arctic species, | am much indebted to Dr. Hansen, who with great liberality has sent me for examination several of the type specimens originally examined by Kroyer, and preserved in the Museum of Copenhagen, as also many other interesting arctic forms described by himself.

I have also to thank the Rev. Mr. Stebbing, Mr. Walker, the Rev. Mr. Norman, Mr. Chevreux, Mr. Schneider, and several other distinguished zoologists for kindly sending me Amphipoda for examination and determination.

My best thanks are also due to the publisher for the readiness with which he has untertaken the publication of such a large work, and for the beautiful manner in which the present Volume has been mounted, both as to type and paper.

October 1894.

G. O. Sars.

AN ACCOUNT

OF THE

CRUSTACEA

NORWAY,

WITH SHORT DESCRIPTIONS AND FIGURES OF ALL THE SPECIES.

BY

G. O. SARS.

VOL. I.

AMPHIPODA.

ee TKI S BF

KRISTIANIA. PUBLISHED BY ALB. CAMMERMEYER

1890.

PRINTING OFFICE OF MALLING.

AMPHIPODA.

Terminology.

(See Pl. 1)'.

Divisions of Body: C Cephalon Ms. Mesosome

es eh asome | Posterior Division. Us. Urosome {|

Anterior Division.

Appendages of Cephalon:

al. Superior antennze (peduncle, flagellum, secondary appendage). a®, Inferior antennz (basal joint (b), olfactory spine (ol), peduncle, flagellum). L. Anterior lip (buccal plate, epistome). le Posterior lip (lobes, lateral corners). M. Mandibles (body (b), masticatory part, cutting edge (c), molar expansion (m), palp (p)). m'. First pair of maxillz (basal part (b), basal

‘ 4 Buceal mass. lobe (1'), masticatory lobe (1*), palp (p)).

( ( m?. Second pair of maxillee (basal part, inner and | outer lobes). : ! mp. Maxillipeds (basal part (b), basal lobes (1'), masticatory lobes (1*), palp (p)). (Eyes Rostrum, Lateral corners).

' Appendages of Mesosome: First pair of legs, or anterior gnathopoda. p?. Second pair of legs, or posterior gnathopoda. p’—p’. Third to seventh pairs of legs, or first to fifth pairs of pereiopoda. Joints in all the legs: 1. coxal, 2. basal, 3. ischial, 4. meral, 5. carpal, 6 propodal, 7. terminal, or dactylus. Appendages to the legs: br. branchial lamella, i. incubatory lamella.

1) The same lettering is used in all the plates to designate the corresponding parts.

Appendages of Metasome: pl.—pl*. First to third pairs of pleopoda (basal part (b), rami (1)). (ep'.—ep*. First to third pairs of epimeral plates).

Appendages of Urosome:

up'.—up*. First to third pairs of uropoda (basal part, rami). t. Telson.

2 Female, G Male, 3 jr. Young male, G + nearly adult male.

Tribe 1.

HYPERTDEA,

Body short and tumid, or very slender, with thin and pellucid integu- ments. Cephalon generally large and tumid; mesosome more or less abbreviated, with the coxal plates small and subequal in size; metasome powerfully developed, compressed, with large epimeral plates; urosome depressed, with the 2 outer seg- ments coalesced. Eyes generally enormously developed. Antenne often imper- fect in female, superior ones without any secondary appendage (excepting the genus Hyperiopsis). Oral parts of various structure; maxillipeds without palps, basal lobes coalesced, masticatory lobes divergent, flap-shaped. Gnathopoda not very strong, subsimilar in the two sexes. Pereiopoda of various structure, some- times very dissimilar. Pleopoda powerfully developed. Uropoda more or less laminar, outer ramus of last pair without any terminal joint. Telson simple. — Parasitic on pelagic animals, especially Meduse.

Remarks. — This is a rather anomalous division of the Amphipoda, which by most authors has been placed at the close of the order. I think, however, it will be more appropriate to follow Boeck in treating of the present group at the head of the order, placing the typical Amphipoda (Gammaridea) in the midst between this tribe and that of the Caprellidea, the latter constituting a far more distinctly degradated type.

Fam. |. Hyperiide.

Cephalon large and deep, almost globular. Eyes occupying the entire lateral walls of the head, visual elements very numerous and elongated, radiat- ing from a central pigmentary mass. Both pairs of antennee with distinctly triarticulate peduncles, the inferior ones originating each from a large and immobile basal joint, flagellum of both pairs in female comparatively short and non-articulated, in male very slender and elongated, multiarticulate. Epi-

stome not projecting. Anterior lip with a large bilobed buccal plate covering

6

the cutting edges of the mandibles. Posterior lip with the lobes subpedi- cellated and wide apart. Mandibles rather powerful, with the cutting edge finely denticulated, molar expansion more or less laminar, palp distinct, triarti- culate and naked. First pair of maxilla without any basal lobe, masticatory lobe densely hairy and having a few slender terminal spines, palp lamellar, uniarticulate. Second pair of maxilla with both lobes densely hairy and ter- minating in blunt points. Maxillipeds with the terminal lobes more or less erescent-like. Gnathopoda imperfectly subchelate, os complexly chelate. Pereio- poda generally not very dissimilar, basal joint of the 3 posterior pairs rather narrow. Incubatory lamelle without marginal sete. Uropoda normal, biramous, rami lanceolate, without spines, but with the edges finely serrated. Telson triangular.

Remarks. — Besides the 4 genera treated of in the following pages and belonging to the Norwegian fauna, Dr. Bovallius enumerates, in his «Systematical list of the Hyperiidea», 5 other exotic genera comprised in the same family, viz., Iwlopis Bovall., Tawria Dana, Hyperiella Bovall., Themistella Bovall., and Phronimopsis Claus. Of the several characters distinguishing the family, the structure of the antennee in the 2 sexes may be named as the most easily recognisable one. Moreover the form of the cephalon and the structure of the oral parts, partly also that of the pereiopoda, afford well

marked differences between this and the other Hyperidean families.

Gen 1. Hyperia, Latreille, 1825. Syn: Lestrigonus, M—Edwards = <.

Cephalon much more deep than long, somewhat flattened in front. Meso- some greatly inflated in the female, with the back evenly vaulted. Antenne in female very small,» subequal. Mandibles with the molar expansion large and finely fluted transversally, palp of moderate size, with the 2 outer joints subequal in length. First pair of maxillee with the palp not very expanded, inner corner produced to a tooth-like projection. Maxillipeds with the ter- minal lobes obtusely pointed, inner edge with small tufts of hair. Gnathopoda scarcely chelate; carpal joint, however, more or less produced inferiorly, especially in the posterior ones. Pereiopoda comparatively short and robust, subequal in length. Uropoda rather broad, with the rami foliaceous. Telson comparatively large.

Remarks. —-This genus, which may be considered the type of the family, comprises several species occurring in different parts of the Oceans. Dr. Bovallius enumerates 10 different species, two of which only belong to

the Norwegian fauna.

7

1. Hyperia galba (Mont). (Pl. 2; Pl. 3, fig. 1). Cancer gammarus galba, Montagu, Linn. Transact. XI, p. 4, pl. 2, fig. 2. Syn: Hyperia Latreilli, M. Edw., « Lestrigonus exulans, Kréyer = , « Hyperia medusarum, Boeck. J

Body of female short and stout, with greatly dilated mesosome, of male considerably more slender and having the metasome much larger than in female. Eye-pigment very narrow reniform, reddish brown. Gnathopoda rather small and only sparingly bristle-beset, carpal joint in both pairs pro- duced, forming in the 2nd pair a narrow process reaching beyond the middle of the propodal joint; the latter attenuated and finely serrated along the inner edge; dactylus of both pairs rather slender and finely denticulated. Pereio- poda almost quite naked. Last pair of uropoda shorter than the urosome, rather broad, especially in the male. Colour pale purplish yellow. Length of female 14 mm, of male 12 mm. Maximum length of arctic specimens, according to Bovallius, 20 mm.

Remarks. — In spite of the opinion supported by Dr. Bovallius, I cannot but believe Hyperia Latreilli of M. Edwards to be identical with H. galba Mont. The said author, it is true, enumerates some minor differences between the two; but none of them can in my opinion be regarded as strictly specific in character. It may moreover be observed, that the figures he gives of H. Latreilli ave from a not yet fully adult male, whereas those of H. galba are from a quite adult specimen.

Occurrence. — Rather common along the whole coast of Norway, found parasitic on Avwrelia, often several specimens, males, females and young ones on each Medusa.

Distribution. — Atlantic coasts of France and Britain, the Cattegat, the Baltic, Arctic Ocean: Greenland, Spitsbergen, Novaja Semlja, Kara Sea,

the Murman coast.

2. Hyperia medusarum, (Miiller). (Pl. 3, fig. 2). Cancer medusarum, O. Fr. Miiller, Zool. dan. prodromus, 2355, p. 148. Syn: Hyperia spinipes, Boeck. In general habitus very like the preceding species. Eye-pigment however, somewhat larger and broader. Antenne very small in the female. Gnathopoda considerably larger than in H. galba and densely hirsute in their outer

part, carpal joint scarcely at all produced in the 1st pair, and but very slightly

so in the 2nd, propodal joint in both pairs oval in form, scarcely serrate along the inner edge, but all over densely spinous, dactylus very small. The 2 anterior pairs of pereiopoda having fascicles of short bristles along the posterior edge. Uropoda almost exactly asin H. galba. Colour dark purplish brown from numerous pigmentary spots distributed over the whole body as also on the limbs. Length of adult female 15 mm.

Remarks. — I think Dr. Boyallius is right in believing the form described by Boeck under the name of Hyperia spinipes to be most likely identical with the Cancer medusarum of O. Fr. Miller, and hence the latter specitic denomination ought to be retained for the present form. Although in its general habitus very like the preceding species, this form may at once be distinguished, on closer examination, by the rather different form and armature of the gnathopoda, a character which suggested the specific name of spinipes proposed by Boeck.

Occurrence. — West coast of Norway, found parasitic on Cyanea, occasionally also on Awrelia, but less frequently than the preceding species.

Distribution. — Arctic Ocean: Greenland and Spitsbergen.

Gen. 2. Hyperoche, Bovallius, 1887.

Syn: Metoecus Kroyer, Tawria Boeck.

Form of body about as in Hyperia, but with the cephalon somewhat more regularly rounded. Inferior antennee in female much smaller than the superior ones; both pairs in male greatly elongated. Mandibles with the molar expansion narrow lanceolate and unarmed. First pair of maxille haying the palp very broad and lamellar. Gnathopoda subsimilar, both distinctly chelate, the carpal joint being produced inferiorly to a compressed knife-like process reaching to the end of, or beyond, the propodal joint, and having the inner edge finely serrate; propodal joint narrow, attenuated, with the inner edge serrate; dactylus rather short. The two anterior pairs of pereio- poda having the carpal joint slightly expanded and compressed; posterior pairs subequal. Uropoda and telson about as in Hyperia.

Remarks. — The generic name Metoecus of Kréyer haying been em- ployed in Zoology at an earlier date, Dr. Bovallius has proposed a new generic denomination, viz., Hyperoche. The same author has likewise shown that the northern form cannot properly be referred to the genus Tawria of Dana, as suggested by Boeck. The genus is easily recognised by the peculiar structure of the gnathopoda. Otherwise it comes rather near to Hyperia, though differmg also somewhat in the structure of the oral parts. Dr. Bo-

9

vallius enumerates 5 species of the present genus; but I regard the validity of some of these species rather doubtful. Thus I believe that only a single species is represented in the northern seas, instead of 3, as suggested by

that author,

3. Hyperoche Kroéyeri, Bovallius. (Pl. 4). Metoecus medusarum, Kroyer, Gronlands Amphipoder. Danske Vid. Selsk. Afhandl. VIE p: 288; pl. 3; figy 15: Syn: Tauria abyssorum, Boeck. » Hyperoche Liitkeni, Bovall.

Body of female short and tumid, of male much more slender and compressed. Cephalon rounded in front, eye-pigment triangular. Mesosome with the back rather vaulted; metasome comparatively slender, with the epimeral plates not very large in female. Gnathopoda almost naked, carpal process of both pairs in female advancing beyond the propodal joint, in male somewhat shorter and narrower. Carpal joint of the 2 anterior pairs of pereiopoda having the posterior edge sharpened and minutely denticulated, terminating with a short triangular process; the 3 posterior pairs comparatively short and almost quite naked, with the basal joint rather narrow. Last pair of uropoda with the basal part about twice the length of the telson, in male rather broader than in female. Colour of female light reddish brown, of male more greyish, from numerous dark pigmentary spots. Usual length 5—6 mm. Maximum length of arctic specimens 15 mm.

Remarks. — 1 believe that Dr. Bovallius is right in rejecting the specific name medusarwn applied to this species by Kroyer, since the form designated by O. Fabricius as Oniscus medusarwm in all probability was a true Hyperia and most likely the species described above as Hyperia me- dusarum. On the other hand I cannot coimeide with that author in regarding Kvoyer’s species distinet from Tauria abyssorwm of Boeck. Nor can I doubt that Dr. Hansen is right in withdrawing the species established by the same author under the name of Hyperoche Liitkeni, as synonymous with the typical species described by Kroyer.

Occurrence. — I have met with this form both off the south and west coasts of Norway up to Lofoten, at times near the surface of the sea, at times in greater depths, but always free, not parasitic. No doubt, however, that it in reality leads a parasitic life on Medusee or some other pelagic animals, as with the species of Hyperia.

Distribution. — Arctic Ocean: Greenland, Labrador, Spitsbergen, the

White Sea, the Siberian Polar Sea.

10 Gen. 3. Parathemisto, Boeck, 1870.

Body somewhat compressed, but with the back scarcely carinated. Cephalon irregularly rounded; mesosome moderately vaulted; metasome well developed, with large epimeral plates. Antenne in female subequal, more elongated than in the preceding genera; in male about as in Hyperia. Anterior lip with a large unequally bilobed buccal plate; posterior Hip with the lobes densely ciliated, lateral corners produced. Mandibles rather strong, cutting edge very broad and minutely denticulated, molar expansion rather large, regularly serrate on the edge, palp with the middle jot very elongated. First pair of maxille with the palp rather expanded, inner edge denticulated and terminating with a small tooth-like projection. Terminal lobes of the maxillipeds acuminated and beset with scattered long sete. Gnathopoda densely hirsute and rather dissimilar; 1st pair simple, with the carpal joint rather broad and not produced inferiorly; 2nd pair subchelate, the carpal joint being produced to a narrow process, which does not, however, reach the end of the propodal joint; dactylus of both pairs rather elongated. The 2 anterior pairs of’ pereiopoda having the carpal joint only shghtly dilated; the 3 posterior pairs very slender, subequal, with the carpal and propodal joints, especially the latter, greatly elongated and almost naked. Uropoda more slender than in the preceding genera. Telson comparatively small.

Remarks. — This genus, established by Boeck, is very nearly related to the succeeding one, Huthemisto, and ought perhaps to be combined with it. The distinctive characters are chiefly the equal-sized antenne of the female, the less powerttl structure of the 2 anterior pairs of pereiopoda and the uniform development of the 5 posterior ones. Besides the northern species described below, the Hyperia trigona of Dana would seem to belong to this genus, as also 2

new species described, the one by Bovallius, the other by the Rey. Stebbing.

4. Parathemisto oblivia, (Kvéyer). (lea ice ): Hyperia oblivia, Kroyer, Gronlands Amphipoder, 1 c¢. p. 70, pl. 4, fig. 19. Syn: Parathemisto abyssorum, Boeck.

sody moderately slender, with the Ist segment of the mesosome much longer than the 2nd. Cephalon rather large, only slightly more deep than long; eye-pigment oval, very dark. Superior antennee in female about as long as the cephalon and the Ist segment of the mesosome combined, flagellum only very slightly curved, about three times the length of the peduncle. Gnatho- poda with the propodal joint about as long as the carpal one; carpal process

of 2nd pair very narrow, reaching beyond the middle of the propodal joint;

11

dactylus very slender. Carpal joint of the 2 anterior pairs of pereiopoda

oblong, with 3—4 slender sete on the posterior edge. Propodal joint of the 3 posterior pairs very slender, nearly as long as the 3 preceding joints com- bined; dactylus narrow and elongated. Last pair of uropoda with the basal part about as long as the urosome, inner ramus slightly larger than the outer and about half the length of the basal part. Body pellucid with dark purplish intestine and scattered pigmentary spots of same colour. Usual length 10 mm. Maximum length of arctic specimens 17 mm.

Remarks. — Although the description and figures given by Kroyer of his Hyperia oblivia ave rather incomplete, I cannot doubt that they refer to the present species, which moreover is stated by Dr. Hansen to occur off the coast of Greenland, whence Kroyer procured his specimens. From P. trigona of Dana it would seem to differ, among other characters, by the much more slender and narrow form of the propodal joint of the 3 posterior pairs of pereiopoda.

Occurrence. — I have repeatedly taken this form in great number on the west coast of Norway up to Finmark, and generally in great depths, from 100 to 200 fathoms. A much smaller form, scarcely exceeding 5 mm in length but otherwise wholly agreeing with the typical species, 1 have met with in less depth and occasionally even near the surface of the sea. On the other hand specimens collected on the Norwegian North-Atlantic Ex- pedition reach the considerable length of 17 mm. All the specimens were taken either by the dredge or by a surface-net fixed to the dredge-rope.

Distribution. — British Islands (Sp. Bate), south coast of Green- land (Kvéyer, Hansen), several Stations of the Norwegian North-Atlantie Ex-

pedition from Lat. 63° to 71° (off Jan Mayen).

Gen. 4. Kuthemisto, Bovallius, 1887. Syn: Themisto, Guérin, 1828.

Body very. slender and compressed, often distinctly carinated dorsally. Cephalon irregularly rounded. Superior antenne in female shorter than the inferior ones and having the flagellum more or less curved. Oral parts almost exactly as in Parathemisto. Gnathopoda likewise of a very similar structure, but the carpal process of the 2nd pair generally larger, and the dactylus shorter. The two anterior pairs of pereiopoda rather powerful, with

the carpal joint greatly dilated, propodal joint slender and admitting of being

12

bent in against the former. Third pair of pereiopoda greatly produced and generally much longer than the 2 succeeding pairs, haying the carpal and propodal joimts very elongated and the latter often peculiarly denticulated, whereas the meral joint is much abbreviated. Uropoda rather slender. Telson small, triangular.

Temarks. — As mentioned aboye, this genus is very nearly related to the preceding one, scarcely differing except in the mutual longitudinal relation of the pereiopoda and in the powerful structure of the 2 anterior pairs. The usual known generic denomination, Themisto, has been changed by Dr. Bovyallius to Luthemisto, because the former name was employed in Zoology anterior to 1828. The genus is represented both in the antarctic and arctic Oceans. Dr. Bovallius enumerates 6 species, one of which, however E. Nordenskjoldi Boyall., has been withdrawn by Dr. Hansen as most probably

only founded on immature specimens of /. libellula, (Mandt). No less than 3

different species belong to the Norwegian fauna.

5. Euthemisto compressa, ((10és). (Pl. 5, fig. 2). Themisto compressa, Goés, Ofvers. af Kgl. Svenska Vetensk. Akad. forhandl. 1865, p- 533, pl. 41, fig 34. Syn: ? Huthemisto bispinosa, Bovall., not Boeck.

Body moderately slender and highly compressed, back distinctly carinated and forming on the posterior segments of the mesosome and the anterior ones of the metasome sharp recurved processes. Cephalon, as seen laterally, rounded triangular, more deep than long; eye-pigment of moderate size, oval. Superior antennae in female about the length of the cephalon, flagellum strongly curved and denticulated on the posterior edge. Posterior gnathopoda with the carpal process almost reaching the tip of the propodal joint, dactylus searcely more than half the length of the latter joint. Carpal joint of the 2 anterior pairs of pereiopoda regularly oval, broadest in the middle, with rather short and unequal bristles on the posterior edge. Third pair of pereio- poda only slightly exceeding in length the 2 sueceding ones, basal joint not expanded, propodal joint very slender and about the length of the 3 preceding joints combined, anterior edge very minutely denticulated throughout and provided at regular intervals with about 10 slender bristles; dactylus rather elongate, unarmed. Posterior pair of uropoda nearly twice the length of the urosome, outer ramus much shorter than inner. Body pellucid, with dark intestine and scattered purplish pigmentary spots on the posterior division of the body. Usual length 12 mm. Maximum length of arctic specimens,

according to Bovallius, 30 mm. (?).

Remarks. — Boeck has referred this form to the genus Parathemisto, because in the figure given by Goés the 3 posterior pairs of pereiopoda are represented as being of uniform length. In reality, however, the 3d pair are, at least in full-grown specimens, distinctly longer than the 2 succeeding ones, although the difference in this species is not nearly so great as in the 2 succeeding species. Moreover the powerful structure of the 2 anterior pairs of pereiopoda, as also the mutual length of the antenne, shows this form to be a true Huthemisto. As to the form named by Dr. Bovallius F. bispinosa Boeck, at least the habitus-figure given would seem more properly to relate to the present than to Boeck’s species.

Occurrence. — Off the coast of Norway I have only observed this form in a single locality, viz., at Hasyig im west Finmark. It occurred here rather sparingly im deep water together with Parathemisto — oblivia.

Distribution. — Arctic Ocean: Davis strait, east coast of Greenland, Jan Mayen at Stat. 225 of the Norwegian North Atlantic Expedition.

6. Euthemisto libellula, (Mandt). (Pl. 6, fig. 1). Gammarus libellula, Mandt, Observationes in Historiam naturalem et Anatomiam comparatam in itinere gronlandico factee, p. 32.

Syn: Themisto arctica, Kroyer.

Body very slender, with the back rounded, not carimated. Cephalon searcely more deep than long, obliquely rounded in front; eye-pigment rather large, obliquely oval. Superior antenne with the flagellum scarcely curved. Gnathopoda haying the propodal joint shorter than the carpal one, carpal process of the 2nd pair nearly reaching the tip of the propodal joint, dactylus very small. Carpal joint of the 2 anterior pairs of pereiopoda broadly ovate, slightly expanded towards the extremity and provided, on the posterior edge, with a regular series of rather elongated sete. Third pair of pereiopoda very elongated, basal jomt expanded, with the anterior edge bulging out on the middle and provided with short bristles, propodal jomt about the length of the carpal, anterior edge with a regular series of rather strong sete placed at regular intervals and increasing in length towards the extremity, outer part of the edge densely spinulous, dactylus slightly flexuous, with a dense tuft of fine spinules at the base. Urosome very slender, about half the length of the metasome. Uropoda likewise very slender, rami of the last pair

subequal in length. Body densely ornamented with dark purplish pigmentary

= Mae

spots, imtestine dark bluish. Length of adult specimens 45 mm. Maximum length of arctic specimens, according to Boyallius, 60 mm.

Remarks. — This gigantic species is easily distinguished from the two other northern forms by the rounded, not carinated, back, the very slender urosome, and by the dactyl of the pereiopoda, especially those of the 3d pair, being densely spimulous at the base. In all these points the form named by Bovallus E. Nordenskjoldi agrees with the present species, from which it can hardly be specifically distmegwished.

Occurrence. — Occasionally this form may be found in large shoals at the north and east coast of Finmark, swimming near the surface of the sea; but generally only young specimens are met with. The figure here given is from a specimen procured on the Norwegian North Atlantic Expedition.

Distribution. — Arctic Ocean, widely distributed: Greenland, Spits- bergen, Jan Mayen, Novaja Semlja, Siberian Polar Sea, numerons stations of the Norwegian North-Atlantic Expedition, both in deep water and at the

surtace of the sea.

ry

7. Euthemisto bispinosa, (Boeck). (Pl. 6, fig. 2). Themisto bispinosa, Boeck, Crust. Amphip. borealia et arctica, p. 8.

3ody rather slender, with the back carinated, the 2 last segments of the mesosome forming (istinct retrovergent dorsal processes. Cephalon nearly twice as deep as long, obtusely truncated in front; eye-pigment rather narrow, almost crescent-like. Superior antennz scarcely longer than the cephalon, flagellum minutely denticulated on the posterior edge and having the extremity distinctly curved. Posterior gnathopoda with the carpal process not nearly reaching the tip of the propodal jot; dactylus comparatively small. Carpal joint of the 2 anterior pairs of pereiopoda irregularly ovate, somewhat tapering im the outer part and fringed with comparatively short and unequal bristles. Third pair of pereiopoda exceedingly elongate and slender, basal joint less expanded than in £. /ibellula, propodal joint very narrow, much longer than the carpal joint and quite straight, anterior edge with only a few small setee in the middle, outer part regularly pectinate, the spinules eradually increasing in length towards the tip of the jot; dactylus very small and unarmed. Last pair of uropoda about twice the length of the urosome, outer ramus much smaller than inner. ‘Telson rather small. Body pellueid, with dark purplish intestine, and ornamented with scattered stellate

pigmentary spots, especially on the posterior division. Length of adult

15

specimens 15 mm. Maximum length of arctic specimens, according to Boeck 25 mm.

Remarks. — In some characteristics, e. g., in the carinated back and the structure of the antenne, this species shows a perplexing resemblance to E. compressa (Goés), and on this account the two species would seem to have been confounded both by Boeck and Bovallius. On closer examination, the present species is, however, easily distinguished by the exceedingly elongate and slender form of the 3rd pair of pereiopoda, and more especially by the peculiar armature of the propodal joint of these legs. It may be observed that this character is also quite distinct in very young specimens, whereas in these the dorsal processes are very inconspicuous or nearly quite obsolete.

Occurrence. — Of this form I have taken a few adult and several young specimens at Sorver and Hasvig in west Finmark, together with FE. compressa and Parathemisto oblivia.

Distribution. — Arctic Ocean: Greenland, Spitsbergen (?); off Nova Scotia (Stebbing).

Fam. 2. Lyceide.

Cephalon large, subglobular, canaliculated inferiorly. Eyes enormous, occupying the entire lateral walls of the head. Antenne originating from the inferior side of the cephalon, very dissimilar; 1st pair rather small, with short uniarticulated peduncle (in female), flagellum rather dissimilar in the two sexes; 2nd pair imperfectly developed in female, very large in male and folded up beneath the cephalon. Oral parts more or less imperfectly developed. Gnatho- poda simple, or complexly subchelate. The 3 posterior pair of pereiopoda with the: basal joint more or less expanded, last pair generally very small. Incubatory lamelle without marginal sete. Pleopoda very powerful. Uropoda normal. Telson triangular.

Remarks. — This family is synonymous with the family Tryphanida of Boeck and Bovallius. I have, however, seen fit to change the name, because, according to the rules of Zoology, the denomination of a family ought to be derived from the genus first established, and as the genus Lycwa of Dana undoubtedly belong to the same family as the genus Tryphana of Boeck, the family must of course be named after the former genus, which is by far the older one. According to the restrictions of Dr. Bovallius, the

family comprises, besides the 2 above mentioned genera, 5 others, viz,

Thamyris Sp. Bate, Thamneus Bovall., Paralycwa Claus, Pseudolycea Claus and Simorhynchus Claus. The family is mainly represented in the tropical

part of the Oceans, the genus Tryphena being the only northern representative.

Gen. 5. Trypheena, Boeck, 1870.

Body comparatively short and stout, with rounded, not carinated back. Cephalon much deeper than the body, slightly produced in front, inferior side deeply canaliculated. _Mesosome more or less abbreviated, metasome greatly developed, urosome comparatively short and depressed. First pair of antenne originating from the inferior side of the head in front, and admitting of being reflexed within the deep ventral furrow; flagellum triarticulate, 1st joint in female rather short, in male globularly expanded and bearing a dense tuft of sensory hairs at the posterior edge, 2nd joint linear with a few sensory appendages near the tip, in male rather narrow and produced inferiorly to a spiniform process, last joint in both sexes narrow styliform. Second pair of antenn fixed, at a great distance from the Ist pair, to the infero-lateral corners of the cephalon; in female very small and immobile, triarticulate, 2nd joint laminar, terminal one minute, scale-like; in male very large, peduncle 4+articulate, the 2 outer joints slender and angularly bent, flagellum very narrow filiform, indistinctly articulate and likewise angularly bent. Anterior lip triangular, with a very short, slightly emarginated buccal plate; posterior lip wanting. Mandibles without any molar expansion, palp naked, biarticulate (in female). Both pairs of maxille forming simple narrow plates without any armature. Maxillipeds large, operculiform; terminal lobes short and broad, erescent-like, unarmed. Gnathopoda small, not chelate; Ist pair with the basal joint very large, lamellar, dactylus spiniform, immobile; 2nd pair rather slender, dactylus densely hairy and terminating with a kind of sensory apparatus (2). Pereiopoda almost naked, 3rd pair the largest, last pair very small. Uropoda comparatively short, with broadly louceolate rami. Telson large, triangular.

Remarks. — Owing to the generally very imperfect investigation of Hyperids by Dana and earlier authors, Boeck has failed to recognise the near relationship of his genus Tryphena to the genus Lycea of Dana. In fact, the only essential difference between the two would seem to consist in a slightly different structure of the gnathopoda, and hence | thought it right, in the Ist part of my «Oversigt af Norges Crustaceer>, to refer Boeck’s species to the said genus. Meanwhile Dr. Bovalius has recently maintained

the distinctness of Boeck’s genus, though referring the genus Lycea to the

17

same family, and as that author has made the Hyperids his special study, I do not feel at present entitled to dissent from his opinion on this point. In the restricted sense in which the genus is taken by Bovallius, it only contains a single species, for the 7’. Nordenskjéldi is quite certainly not specitically distinct.

8. Tryphena Malmi, Boeck. Gzb De eTryphana Malini, Boeck, Crust. Amphip. borealia et arctica, p. 9. Syn: T. Nordenskjéldi, Bovall. = o. 2 IT. Boecki, Stebbing = ¢.

Cephalon about half the length of the mesosome, front in female obtusely rounded, in male angularly produced; ocular pigment rounded oval in male somewhat narrowed dorsally. Mesosome not very tumid, nearly as long as the metasome. First pair ot antenne with the 2nd joint of the flagellum in temale linear compressed and about the length of the peduncle and Ist joint of the flagellum combined, obliquely truncated at the extremity and bearing 4 sensory appendages; in male much narrower and ciliated on the posterior edge, the spiniform process about as long as the terminal joint, the latter in both sexes scarcely longer than the sensory appendages. Anterior gnathopoda with the basal joint about as long as the remainder part of the leg, propodal joint compressed oval, bearing a short spine on either edge, and produced at the tip, beneath the dactylus, to a short tooth-like process. Posterior gnathopoda more slender than the anterior ones, outer part very hairy, propodal joint narrow and as long as the dactylus. All the pereio- poda, saving the last pair, having the propodal joint produced at the tip beneath the dactylus to a short tooth-like process; 3rd pair about as long as the mesosome. Basal joint of the 2 posterior pairs of pereiopoda con- siderably more expanded in male than in female. Urosome about as long as the last segment of the metasome, rami of the uropoda subequal. Telson in male somewhat larger than in female, slightly exceeding the basal part of the last pair of uropoda. Colour more or less reddish, speckled with small purplish pigmentary spots. Length of adult female 5 mm, of male 6 mm.

Remarks. — The habitus-figure of the female given by Boeck in his work on the Scandinavian Amphipoda is very bad and misshaped, and this may have been the cause why Dr. Bovallius could not recognise the specimen examined by him as the male of T. Malmi. True, the sexual differences in this form are rather striking, not only as regards the structure of the antenne, but also in several other points; but on a closer comparative examination of

both sexes, their specific identity cannot be misunderstood. The form described 3

18

by the Rev. Stebbing trom the Challenger Expedition as 7. Boecki does not seem to differ in any essential manner from male specimens of the present species.

Occurrence. — 1 have tound this interesting form in three different localities on the west coast of Norway, viz., at Folgero and Sunde in Sondhordland, and in the Foldentjord at Apelver. In all 3 places it was procured by the dredge from comparatively great depths, 80—200 fms. Boeck collected his specimens likewise at a considerable depth in the outer part of the Hardangertjord, at Lyngholmen.

Distribution. — Off the Fero Islands at Lat. 65° N. (Bovallius); North Atlantic at Lat. 18° 8’ N. (Stebbing).

Fam. 3. Scinide.

Cephalon small, not tumeticated. Eyes very minute. Superior antenne rather large, straight, stylitorm, divergent, similar in the two sexes; inferior antenne in temale quite rudimentary, in male very slender and angularly bent. Mandibles without palps. Maxille well developed. Maxillipeds with lanceolate terminal lobes. Gnathopoda simple, not subchelate. Pereiopoda very slender, the 3 posterior pairs rather unequal, with narrow basal joints, last pair the smallest. Metasome in female not very powerful, epimeral plates small. Urosome depressed. Uropoda impertectly developed, more or less sword-shaped. Telson very minute.

Remarks. — This is a very anomalous group of Hyperids, dittering from the typical forms in many respects, among others by the very small eyes and the less powerful development of the metasome. The structure of the oral parts and of the urosome is, however, evidently Hyperidean im

character. The family comprises as yet but a single genus.

Gen. 6. Scina, Prestandrea, 1833. Syn: Tyro, M. Edw,, 1840. » Clydonia, Dana, 1852 3ody in female rather tumid, attenuated posteriorly. Cephalon trunc- ated in front, scarcely deeper than the body. Mesosome rather large, with broad vaulted back, metasome compressed. Eyes located at the infero-lateral

corners of the cephalon in projecting tuberculiform prominences, visual elements normal, very few in number. Superior antenne consisting of a short and thick, uniarticulate peduncle and a large styliform, biarticulate flagellum, the terminal jomt of which is very small. Inferior antenne in female biarticulate, originating from a large basal joint completely anchylosed with the cephalon, proximal jomt very small, distal one thread-like; in male rather elongated, with distinctly +articulate peduncle and filiform multiarticulate flagellum. Anterior lip very small, without any buccal plate; epistome slightly projecting, carinated. Posterior lip wanting. Mandibles with the masticatory part simple laminar, without any armature. First pair of maxille with the basal lobe distinctly developed though nearly bare, masticatory lobe without spines but divided at the tip in a few acuminated projections, palp lamellar, uni- articulate. Second pair of maxille with both lobes acuminated and strongly inflexed, without sete but finely hairy, the exterior provided with a short lateral tooth. Maxillipeds with the basal part rather small, the terminal lobes very thin, foliaceous and exserted to a narrow point. Gmnathopoda slender, subequal, densely hairy in the outer part. Pereiopoda very slender and nearly naked; 3rd pair the longest and generally angularly bent, basal joint very elongated and haying the one or both edges strongly serrate, pro- podal joint and dactylus very small. Last pair,much smaller than the rest. The 2 segments of the urosome very sharply defined. Last pair of uropoda with a short lateral ramus exteriorly, the others simple, with the peduncle not detined. Telson extremely small.

Remarks. — Dr. Bovallinus has been the first to call attention to the fact, that the genus Clydonia of Dana is in all probability identical with the genus Tyro established by Milne Edwards at a much earlier date, and hence has proposed to restore the latter name as the elder one tor the genus and to name the family accordingly Tyronide, instead at Clydoniidw. | As recently shown by the Rey. Stebbing there is, however, a still older name, which of course ought to be preferred to that of M. Edwards, viz the denomination Scina, proposed by Prestandrea as early as 1833 for a form, which evidently is congeneric with that described by Milne Edwards, and accordingly the name of the family must be changes to Scinide. The genus comprises, according to Dr. Bovallius, no less than 10 different species, distributed in different parts of the Atlantic, the Pacific and the Mediterranean. In the northern Ocean it is only represented by a single species, occurring on the

coast of Norway.

20

9. Scina borealis, G. 0. Sars. (Pl. 8). Clydonia borealis, G. O. Sars, Oversigt af Norges Crustaceer I, p. 75, pl. 3 fig. 1.

Cephalon more deep than long, with a pair of small tubereuliform pro- jections just above the insertions of the superior antenne. The latter about halt as long as the body, excepting the urosome; proximal joint of the flagellum serrated at both edges, more minutely at the superior one, its basal portion somewhat more incrassated in the male than in the female and densely hairy. Inferior antenne in male about as long as the body, last joimt of the peduncle very elongated, flagellum 5—6-articulate. Propodal joint of Ist pair of gnathopoda shorter than the carpal joint, that of 2nd pair about as long as the latter. Third pair of pereiopoda longer than the 4th; basal joint serrated on both edges and jutting out at the end as an acumi- nated process overhanging the ischial joint, propodal joint about half as long as the carpal one. Last pair of pereiopoda scarcely half as long as the penultimate one, basal jomt about the length of the remainder part of the leg. First pair of uropoda strongly denticulated on the inner edge, exterior ramus both in this and the succeeding pair obsolete, that of the last pair about as long as the basal portion. Telson acutely triangular. Body very pellucid, with light red intestine and oral region, and with scattered reddish pigmentary spots on the posterior division. Length & mm.

Remarks. — The species established by Dr. Bovallius under the name ot Tyvo Clausi is very nearly related to, if not identical with, the present species, only differing by the 3rd pair of pereiopoda bemg somewhat shorter and by the poor development of the propodal joint of these legs. In all other respects, and especially in the structure of the urosome, with its several appendages, it agrees exactly with the northern form.

Occurrence. — 1 first detected this interesting Hyperid many years ago at Lofoten. It occurred here only at very great depths from 200 to 300 fs. Subsequently I have met with this form also in two other localities on our coast, viz., in the outer part of the Drontheimstjord at Bejan, and in the Christianiatjord at Hanko. Here also it was only procured from com- paratively great depths (100—150 fs.) by the aid of the dredge or a fine handmet fixed to the dredge rope at a short distance from the dredge.

Tribe 2.

GAMMARIDEA,

Remarks. — This tribe comprises the ordinary or typical Amphipoda and constitutes by far the greater part of that order. Of course it must be divided into numerous subordinate groups, which however, do not bear exactly the same systematical relation to each other. Owing to the latter cireumstance, some of the later authors, for instance Boeck, only admit a very restricted number of true families, whereas some of the latter, and especially the family Gammaride, have been again divided into numerous sub-families. As there, however, is far from being full concord among the authors about the limits of the several families and sub-families established, I think it will be at present more suitable to avoid such a complicated classification and to restrict ourselves to a subdivision of the tribe into a number of families only, remembering, however, that some of these families are rather nearly related,

while others are more sharply defined.

Fam. J. Orchestiide.

Body now rather tumid, now more or less compressed, with the meta- some and uresome comparatively short and stout. Coxal plates rather large, the 4th pair not emarginated posteriorly, 5th pair deeply bilobed. Cephalon truncated anteriorly and having the buccal mass greatly projecting inferiorly. Eyes comparatively small and situated near the dorsal face of the cephalon. Superior antenna generally very much shorter than the inferior and without any accessory appendage. Inferior antenne more or less pediform, peduncle rather elongated and having its basal joint coalesced with the cephalon. Anterior lip large, rounded; epistome applanated. Posterior lip membranous, with projecting lateral corners. Mandibles without palps, very powerful, cutting edge divided into two superposed lamella which are strongly denticulated on the edges, molar expansion large and thick; between both a series of curved sete.

4 — Crustacea.

22

First pair of maxille with the palp obsolete, or nearly so, masticatory lobe well developed and furnished at the tip with several strong denticulated spines, basal lobe very narrow, with 2 short and densely ciliated curved set at the tip. Second pair of maxille with the lobes rather broad and densely seti- ferous on the inner edge. Maxillipeds having the masticatory lobes very small and rounded, basal lobes much larger and armed at the tip with short teeth and bristles; palp rather large, with the joints complanated and short hairy at the edges. Gnathopoda of various structure in the several genera, 2nd pair more generally very different in the two sexes. Pereiopoda rather strong, edged with tufts of short spines, the 3 posterior pairs successively increasing in length and having the basal jot broad and laminar. Branchial lamelle generally very small and vesicular in form. Pleopoda poorly developed. The 2 first pairs of uropoda strong, with both rami, as also the basal part, den- ticulated; last pair very small, with only a single minute ramus. ‘Telson short and thick.

Remarks. — This is a rather distinct family, which even by Milne-Kd- wards and other authors has been elevated to the rank of a tribe (Saltatoria). It comprises a number of Gammaridea, which more or less have adapted themselves to a terrestrial life and im accordance therewith exhibit some particular characters not found in other Amphipoda. Moreover their mode of progression, when out of water, is very peculiar and is effected by quick leaps or abrupt hops. Besides the 3 genera described below and belonging to the Norwegian famma, two other exotic genera have been established, viz, Orchestoidea Nicolet and Tallorchestia Dana, both of which seem to be nearest

related to the genus Orchestia.

Gen 1. Talitrus, Latreille, 1802.

Body less compressed, with broadly rounded back. First pair of coxal plates smaller than the 2nd, 5th pair rather large, regularly bilobed. Superior antenne very small, much shorter than the peduncle of the interior; the latter elongated, subpediform, much stronger in male than in female, the 2 basal joints more or less completely coalesced with the cephalon; no olfactory spine. First pair of maxille with only a slight rudiment of a palp. Maxillipeds with the palp rather short and broad, terminal joint, or dactylus, quite wanting. Anterior gnathopoda simple, not subcheliform, somewhat stronger in male, carpal joint elongated and linear in form. Posterior gnathopoda in both sexes of similar structure, rather feeble and almost bare, terminating with an imper-

fectly cheliform hand, the dactylus being quite rudimentary. Branchial lamelle

very small. Incubatory lamelle likewise small, lanceolate, with only few marginal sete. Telson rather broad, rounded at the tip.

Remarks. — The present genus is chiefly distinguished from Orchestia

by the anterior gnathopoda beimg simple, not subcheliform, and the posterior

ones being exactly alike in the two sexes; moreover by the less compressed

form of the body. It comprises only a few species, the validity of which

would moreover seem to be rather doubtful.

1. Talitrus locusta (Pallas). (PI. 9). Oniscus locusta, Pallas, Specil. Zool. fase. 9, tab. 4, fig. 7. Syn: Talitrus saltator (Mont.), Edw.

Body comparatively short and robust, with the coxal plates scarcely as deep as the mesosome, Ist pair triangular, more or less covered by the 2nd; 5th pair nearly as deep as the preceding ones. Cephalon rather deep, trans- versely truncated in front, with the buccal mass greatly projecting. Eyes comparatively small, rounded, with black pigment. Superior antenne scarcely reaching beyond the penultimate joint of the peduncle of the inferior; flagellum much shorter than the peduncle, 7—8-articulate. Inferior antenne in female about three times the length of the superior, with the last jomt of the peduncle as long as the two preceding ones combined, flagellum about the length of the peduncle; in male much stronger, sometimes nearly as long as the whole body. Anterior gnathopoda with the propodal joint scarcely more than half the length of the carpal and slightly tapering distally. Pleopoda with the basal part about the length of the rami and beset on the outer edge with slender spines. © Last pair of uropoda with the ramus nearly as long as the basal part and bearing a single slender spine at the tip and several short ones on the outer edge. Telson nearly twice as broad as it is long, with bunches of small spines dorsally. Colour, when alive, light greyish white, with dark bluish markings on the back. Usual length of adult male 16 mm; that of female somewhat less.

Remarks. — Although the description and figure given by Pallas of his Oniscus locusta is very imperfect, there is all reason to believe, that he has had this form before himself and according to the rules of priority his specific name locusta ought therefore to be preferred to that of salfator proposed by Montagu.

Occurrence. — 1 have met with this form rather plentyfully on the sandy beaches of Lister, on the south coast of Norway, where it occurred

near the level of spring tide highwater mark, beneath old sea-weed. Boeck

has collected it under similar conditions on the shores of Karmé, and several specimens are preserved in our university Museum, brought home by the late professor Rasch, probably from the district of Christiansund. It is a very active animal, being enabled to jump away by very quick and abrupt leaps, so that it is only to be caught with great difficulty.

Distribution. — Atlantic coast of Europe: Denmark, Br*tish Islands, France; Mediterranean; coast of Algiers (Chevreux); Azores (Barrois).

Gen. 2. Orchestia, Leach, 1814.

Body more slender and compressed than in Talitrus. First pair of coxal plates rather small; 5th pair almost as deep as the preceding and deeply bilobed. Cephalon, antennee and oral parts almost exactly as in Talitrus. Anterior gnathopoda small, subcheliform in both sexes, the propodos having a distinctly defined palmar border. Posterior enathopoda very dissimilar in the two sexes, in female about as in Talitrus, in male very strongly developed, terminating with a very large and powerful subcheliform hand. Pereiopoda about as in Talitrus, but the last pair somewhat more elongated and often peculiarly modified in the male. Branchial lamelle small. Incubatory lamellae of the same structure as in Talitrus, but considerably larger. Appendages of metasome and urosome almost as in the latter genus.

Remarks. — This genus is chiefly distinguished from Talitrus by the structure of the gnathopoda, the Ist pair of which, instead of being simple, are subcheliform in both sexes, whereas the 2nd pair show a very unequal development in the two sexes. The genus is widely distributed and comprises numerous species, which in their habits closely resemble the Talitri, being evidently terrestrial in character. In Norway only a single species has

hitherto been recorded.

2. Orchestia littorea, (Mont).

(Elea10): Cancer (Gammarus) littoreus, Montague, Linn. Trans. IX, p. 96, Pl. 4, fig. 4. Syn: Tailtrus tripudians, Kroyer, Orchestia Euchore, F. Miiller. +

Body rather slender, with the back evenly rounded throughout. Cepha- lon scarcely longer than the Ist segment of the mesosome. First pair of coxal plates triangular, much smaller than the 2nd and partly covered

by the same; 5th pair haying the anterior lobe somewhat larger than the

posterior. Eyes irregulary rounded, black. Superior antenne scarcely rea- ching beyond the penultimate joint of the peduncle of the inferior, flagellum 7—S8articulate. Inferior antenne about 1/3 as long as the body, somewhat stron- ger in male than in female. Anterior gnathopoda having the propodosshorter than the carpus, in female oblong quadrangular, with the palm transversely truncated, in male dilated at the tip, with the palm rounded. Posterior gnathopoda in male having the propodos very large, oval, dilated distally, palm transversely arcuate and defined below by an obtuse projection. Last pair of pereiopoda in male with the meral and carpal joints greatly dilated, the former triangular, the latter rounded quadrangular. Pleopoda with the basal part much longer than the rami and quite bare. Last pair of uropoda with the ramus very small and narrow, scarcely half as long as the basal part. Telson about as long as it is broad, very slightly emarginated at the tip. Colour of female uniform greenish, of male yellowish with brown trans- versal bands. Length of female 15 mm., of male 17 mm.

Remarks. — Boeck has identified this species with the Oniseus gam- marellus of Pallas and accordingly named the species Orchestia gammarellus. As there, however, are several nearly related species of the present genus, and it is impossible from the imperfect description and figure given by Pallas to decide with certainty, what species he has observed, I think it will be best to retain the specific name proposed by Montagu. The present species may be best known from the related forms by the structure of the posterior gnathopoda in the male, partly also by the peculiar development of the last pair of pereiopoda of the same.

Occurrence. — This is one of our most common Amphipoda, occurring in considerable numbers along the shores of the whole south and west coast of Norway, at least up to the Trondhjemsfjord. It is met with, as the Talitri, beneath old sea-weed at high water mark, and moves about in a quite similar hopping manner. While, however, the Talitri seem to be confined to sandy beaches, this form may very often also be collected on the rocky shores, and in the crevices between stones, hiding itself with great dexterity within the muddy deposit when disturbed.

Distribution. — Denmark, the Baltic, Belgium, British Islands, France, Mediterranean, the Black Sea (Czerniavsky), coast of Algiers (Chevreux),

Madeira (Morelet), Azores (Barrois).

Gen. 3. Hyale, Rathke, 1837. Syn: Allorchestes, Dana = G,

Nicea, Nicolet = Q.

Body greatly compressed, but with the back rounded. The 4 anterior pairs of coxal plates rather deep and subequale in size, the 3 posterior ones much lower. Superior antenne longer than the peduncle of the inferior, the latter somewhat stronger in male than in female. “ Oral parts on the whole rather similar in structure to those in the 2 preceding genera, saving that the Ist pair of maxille has a distinct though very small and narrow palp, and that the palp of the maxillipeds consists of the normal number of joints. Both pairs of gnathopoda subcheliform, in female nearly subequal, im male very unequal, the posterior ones being much stronger and terminating with a very large and powerful hand. Branchial lJamelle of normal structure, though rather small. Incubatory lamelle very large and broad, with the edges densely ciliated. Pleopoda somewhat larger than in the 2 preceding genera and haying the natatory sete plumose. Uropoda about as in Orchestia.

Telson small, unarmed, cleft to the base.

Remarks. — Yt is evident that Boeck was right in uniting the two genera Allorchestes Dana and Nicea Nicolet, as only founded on sexual cha- racters, and likewise in stating both to be merely synonymous to the genus Hyale of Rathke. In several characters this genus would seem to form a connecting link between the «Saltatoriay and «Natantia» of earlier authors, and the species are also in their habits not so evidently terrestrial as those belonging to the 2 previously mentioned genera. The genus comprises numerous species occurring, it would seem, in all parts of the world. Two distinct

species belong to the Norwegian fauna.

3. Hyale Nilssoni, (Rathke). (PI 11, fig 1). Amphithoe Nilssoni, Rathke, Acta Acad. Leop. T. XX, p. 264. Syn: Amplhithoe Prevosti, Rathke, Orchestia nidrosiensis, Kroyer.

Segments of body not very sharply demarcated from each other, the back being quite evenly vaulted. Cephalon longer than the 1st segment of the mesosome, lateral corners slightly projecting between the bases of the antenne. First pair of coxal plates scarcely smaller than the 3 succeeding ones, the latter somewhat deeper than the body and rounded inferiorly, 5th pair much lower than the preceding ones, anterior lobe much the larger.

Eyes small, circular. Superior antenne in female nearly as long as the inferior, flagellum longer than the peduncle, 6-articulate; in male only slightly reaching beyond the peduncle of the latter. Posterior gnathopoda in female a little larger than the anterior, propodos of both pairs about as long as the 2 preceding joints combined, elongated quadrangular, palm transversely truncated and defined below by an almost right angle. Anterior gnathopoda in male haying the propodos somewhat broader than in female, with the palm evenly curved; posterior ones very largely developed, propodos oval, scarcely tapering, palm obliquely arcuate and defined below by an obtuse projection. Propodal joint of the pereiopoda scarcely dilated, having tutts of small spines on the inner edge, dactylus comparatively small. Last pair of uropoda with the ramus scarcely more than half as long as the basal part and terminating with a tuft of short spines. Telson about twice as broad as it is long, lobes nacked and angular in form. Colour greenish. Length of adult female 6—7 mm, of male 8 mm.

Remarks. — As pointed out by the Rey. Mr. Stebbing, Boeck has errone- ously confounded this and the following species. The habitus-figure of the female given by that author as also the figure of the 2nd gnathopoda of the male, undoubtedly refer not to Rathke’s species but to the form described below as H. lubbockiana. From that species the present form is easily known by the different structure of the gnathopoda, as also by that of the terminal part of the pereiopoda.

Occurrence. — The present species would seem to occur along the whole coast of Norway, from the Christianiafjord up to Vardo, where it has been recently found by Mx. Schneider, curator of the Tromso Museum. I have myself taken it in several places on our west coast, near ordinary tide-mark, between sea-weed. It is very active and, when out of water, has a similar power of making abrupt leaps as the Talitri and Orchestiz.

Distribution. — Atlantic coast of Europe: Bohuslehn, Denmark, British

Islands, France; Adriatic (Heller); Azores (Barrois).

4. Hyale lubbockiana, (Sp. Bate). : (EAR ahi ie Py Nicea lubbockiana, Sp. Bate, Cat. Amphip. Brit. Museum, p. 51, PL VIII, fig. 3. Syn: Allorchestes imbricatus, Sp. Bate = oy, Hyale Nilssoni Boeck (part). Segments of body rather sharply demarcated from each other, giving the back a subimbricated appearance. Integuments on the whole much firmer than in H. Nilssoni, the edges of the coxal plates thickened and slightly crenulated.,

28

Antenne somwhat more robust, but otherwise rather similar. Gnathopoda of female having the propodos comparatively larger, much longer than the 2 preceding joints combined, oblong oval in form, with the palm very oblique and less distinctly defined below; 2nd pair in male with the propodos oblong in form, distinctly tapering toward the tip. Pereiopoda very robust, edged with scattered small spies, propodal joint, especially of the 3 posterior pairs, considerably dilated and armed on the anterior edge below the middle with 2 unusually strong serrated spines, dactylus very powerful, falciform curyate. Colour yellowish. Length of female 7 mm.

Remarks. — This is evidently a well marked species, differing very decidedly from the typical form by the peculiar imbricated appearance of the body-segments and especially by the rather different structure of the legs. The colour also is rather dissimilar,

Occurrence. — 1 have myself only met with a single female specimen of this species, which was taken on the west coast of Norway. In our Uni versity Museum are, however, 2 specimens, male and female, collected by Boeck, the one on the shores of Karmo, the other at Farsund (south coast of Norway). According to the Rey. Mr. Stebbing, this species is far less active than H., Nilssoni, quite wanting the power of leaping, when out of water.

Distribution. — British Islands, France, coast of Algiers (Chevrewx).

Fam. 2. Lysianasside.

Body generally rather high, more or less compressed, glabrous, with the back evenly vaulted. Coxal plates deep, 4th pair generally the largest and deeply emarginated posteriorly to receive the rounded 5th pair. Meta- some well developed, with large epimeral plates. Urosome short and thick, more or less conyex above. Superior antenne furnished with an accessory appendage, peduncle short and thick, flagellum more or less elongated, with the 1st joint generally rather large ond beset with dense tufts of sensitive hairs. Inferior antenne more slender than the superior and having the basal joints not coalesced with the cephalon, flagellum in male often greatly elongated and filiform. Epistome generally projecting in front of the anterior lip; the latter more or less produced anteriorly. Mandibles less strong than in the Orchestiide, cutting edge simple, not denticulated, molar expan- sion rather small or quite wanting, palp large, triarticulate; between the latter and the cutting edge a more or less distinct rounded ac-

cessory lobe, First pair of maxille with the palp generally well devel-

29

oped, biarticulate, rarely quite rudimentary; 2nd pair with the lamelle more or less elongated. Maxillipeds large, with the masticatory lobes generally largely developed and laminar, basal lobes much smaller and close together, palp elongated, 4-articulate. Anterior gnathopoda more or less prehensile, generally not very strong, but sometimes largely developed and subchelate ; posterior ones always very feeble and slender, highly flexible and furnished with dense tufts of tactile hairs, dactylus as a rule quite rudimentary. The 3 posterior pairs of pereiopoda successively increasing in length and having the basal joint laminar. Branchial lamellae large, sometimes folded transversally on the one or both sides. Incubatory lamellae edged by slender sete. Pleopoda rather powerful. Uropoda with the rami more or less lanceo- late, last pair well developed, biramous, generally unlike the preceding pairs and having the outer ramus biarticulate. Telson flattened, entire or more or less deeply cleft.

Remarks. — The Lysianasside form a very natural subdivision of the more typical Amphipoda, and in my opinion ought to be classed as a family equally distinct as the Orchestide. Boeck, however, did not regard this group as merely a sub-family of the family Gammaride. In the general habitus the numerous forms comprised in this family exhibit a rather uni- form appearance, and it is not very long since they were all referred to a single genus, Lysianassa. It is the merit of the late Dr. A. Boeck, by a closer examination of the oral parts in the different forms, to have pointed out certain distinctive characters apparently of generic value. By reason of these characters he found himself able to subdivide the earlier genus Lysianassa or Anonyx into a great number of separate new genera, and, although some of the latter have not been sufficiently well characterised, the greater part of them must, in my opinion, evidently be supported. The family would seem to be chiefly characteristic to northern latitudes, and in the arctic seas some of the species occur in quite an astonishing abundance, having a great im- portance in cleansing the bottom by devouring the carcasses of the several

ereat mammals, such as whales and seals, which are found there.

Gen. 1. Trischizostoma, Boeck, 1860.

Body moderately compressed, with the back broadly rounded. Cepha- lon produced anteriorly over the base of the superior antenne, lateral angles not projecting. Second pair of coxal plates much larger than the other and greatly dilated inferiorly. Epimeral plates of metasome large, rounded. Eyes

very large, occupying the greater part of the sides of the cephalon. Superio1 5 — Crustacea.

antenne shorter than the inferior, accessory appendage well developed, with the 1st joint laminar. Oral parts greatly projecting inferiorly and crowded together in the form of a trifid tube. Epistome not projecting. Anterior lip very elongated and narrow; posterior lip with the lobes acutely lanceolate. Mandibles with the masticatory part styliform produced, cutting edge very narrow, sharpened and obliquely truncated, molar expansion quite wanting, accessory lobe inconspicuous, palp very large and densely setous. First pair of maxille with the masticatory lobe very narrow and divided at the tip into small claw-like teeth, basal lobe small, unarmed, palp very minute, but distinctly biarticulate. Second pair of maxille with both lobes very narrow, stylitorm. Maxillipeds rather large, masticatory lobes linguiform, projecting inferiorly and partly encompassing the other oral parts at the sides, basal lobes very narrow, unarmed, palp geniculate on the middle, with the terminal joint lanceolate. Anterior gnathopoda enormously developed, prehensile, terminating with a very large subchelate hand, which in the adult animal becomes inverted in such manner, that the dactylus originates from the infero- posterior corner of the propodos and is bent forwards against the strongly denticulated palm. Posterior gnathopoda quite of the structure typical to the Lysianassidee. Pereiopoda not very large, the joints more or less compressed and only beset with very minute and scattered spimes. Branchial lamelle very large and of irregular form. Incubatory lamelle rather broad and fringed with numerous slender setee. Pleopoda very powerful. Uropoda with the rami broadly lanceolate and almost bare, last pair with the outer ramus biarticulate. Telson small, entire.

Remarks. — In classing this remarkable form, | have seen fit to dissent widely from the views supported by earlier authors. Boeck regards this ani- mal as the type of a distinct family (Prostomate), which he places at the head of his division Gammarina, immediately before the Orchestiide, and Dr. Bovallius has classed it, together with the genera Synopia Dana and Hyperiopsis GO. Sars, within a distinct tribe, Synopidea, constituting, however, within the latter, a particular family, T'rischizostomatide. Finally Prof. Lillje- borg considers it the type of a subfamily, T'rischizostomatina, placing it in the vicinity of his sub-family Phovina. Although Boeck has mentioned some points of agreement with the Lyssianassidee, none of these authors would seem to have recognised the near relationship, which in fact exists between this animal and the true Lysianasside. The agreement is indeed so very close, that the present form, in my judgement, unquestionably ought to be classed within the very same family. The oral parts have not yet been exactly examined in their details, neither by Boeck, nor by Dr. Bovyallius. Though

at first sight very anomalous, they are found, on a closer examination to be

dl

in reality constructed upon the very same type as in the true Lysianasside, and in some of the latter, for instance Acidostoma (see Pl. 14, fig. 2) the agreement is quite unmistakable. As to the anomalous appearance of the anterior gnathopoda, Dr. Bovallius has shown this to be merely due to a peculiar torsion of the outer part of the leg, whereby the hand becomes quite inverted in the adult animal, whereas in the young these limbs exhibit a far more normal appearance, nearly agreeing with that met with in the genus Normania (see Pl. 13, fig. 1). On the other hand the posterior gnathopoda are indistinguishable, both as to form and structure, from those in the typical Lysianasside. - Finally the urosome, which in Boeck’s opinion, is evidently Hyperiidean in character, essentially differs by being divided into 3 distinct seoments and by the last pair of uropoda having a distinct terminal joint, as is the case in the greater part of the typical Gammaridea. Moreover, the whole exterior habitus and the structure of both the antenne and the legs pretty well agrees with that met with in the Lysianasside, no essential

difference whatever being found to exist.

1. Trischizostoma Raschi, (Boeck). (Pl. 12). Trischizostoma Raschi, Boeck, Crust. Amphip. bor, & arct. p. 11.

Body glabrous, moderately slender, with the back evenly vaulted. Cephalon rather short, narrowed inferiorly, frontal projection horizontal, obtuse at the tip. Coxal plates scarcely as deep as the body, Ist pair very small and partly covered by the 2nd; the latter greatly expanded inferiorly, jutting out both anteriorly and posteriorly as a triangular lobe; the two succeeding pairs almost equal-sized, obliquely oval, 4th pair truncated at the tip and deeply emarginated posteriorly to receive the 5th one, the posterior lobe of which is much deeper than the anterior; the 2 posterior pairs rather small, Last pair of epimeral plates of metasome nearly right-angled. First segment of urosome deeply impressed at the base dorsally. Eyes successively expanding superiorly, nearly confluent, though separated by a narrow stripe above in the middle. Superior antenne a little longer than the cephalon, Ist jomt of the peduncle much longer than the other 2 combined, flagellum 9-articulate, with the Ist joimt very large, accessory appendage about the length of the latter, triarticulate, the 2 outer joints very small. Inferior antenne twice the length of the superior, penultimate joint of the peduncle the largest, flagellum composed of about 24 articulations. Anterior gnatho-

poda with the propodos greatly inflated, rounded triangular, forming anteriorly

a distinct angle, palm nearly straight and armed with recurved teeth, those at the extremity much stronger and claw-like; dactylus very strong, curved at the tip. Posterior gnathopoda very slender, propodal joint oval and densely hairy, dactylus yery small and rudimentary. Meral joint of the 2 anterior pairs of pereiopoda, especially that of the 2nd pair, laminarly dilated. The 3 posterior pairs of pereiopoda comparatively short, successively increasing in length, basal joint laminar, and forming in the anterior ones an angular projection posteriorly. Uropoda only sligtly decreasing in size posteriorly, rami subequal. Telson rounded, almost as broad as-it is long, tip obtusely truncated. Colour!) whitish, with a more or less distinct light reddish tinge on the sides of the body. Length of the largest specimen examined 28 mm.

, Remarks. — This is the only, as yet, known species of the genus. All the specimens, which have hitherto been examined, were females, some of which had their incubatory pouch filled with eggs or young. In the latter, as stated above, the anterior gnathopoda have not yet assumed their peculiar torsion and of course exhibit an appearance rather different from that of the adult animal (see fig. p! jx.)

_ Occurrence. — The present remarkable form was first detected by the late Prof. Rasch on the Storeggen-bank, outside of the west coast of Norway, from a depth of about 100 fathoms. The specimens were obtained by sub- merging in the dredge the skinned body of a newly shot bird to which they were found clinging. It has subsequently been taken by Mr. Storm, curator of the Drontheim Museum, from the skin of the common black dog-tish (Spinax niger), fished in the neighbourhood of the town. Finally Dr. Bovallius procured a few specimens at Tjoto in Nordland and in the Hardangertjord. No doubt the species leads, as a rule, a parasitic life, and this may easily explain the peculiar formation of the anterior gnathopoda and oral parts. Out of Norway this form has not yet been recorded.

Gen. 2. Normania, Boéck, 1870.

Body comparatively short and stout, with the coxal plates not very deep. Cephalon of normal appearance. Eyes with the visual elements unw sually large. Antenne comparatively slender but not very elongated. Epi- stome applanated, not defined from the anterior lip. Mandibles of the usual structure, palp originating nearer the base than does the small molar expan- sion, very slender and almost bare, saving a few terminal sete. First pair of maxille with the palp well developed, last joint laminar expanded, basal

lobe comparatively short, with 2 small apical sete. Second pair of maxille

') According to a communication from Mr. Storm.

33

with the lobes rather narrow, «setous at the tip only. Maxillipeds smaller than usual, masticatory lobes largely developed, laminar, broadly rounded at the extremity, basal lobes narrowly produced, palp rather small, by far not reaching to the tip of the masticatory lobes, terminal joint obsolete. An- terior gnathopoda rather strong, prehensil, terminating with a powerful and greatly inflated subchelitorm hand; posterior ones very slender, propodal joint oblong, slightly produced at the end beneath the rudimentary dactylus, so as forming an inperfect minute chela. Pereiopoda extremely slender, the penultimate pair the longest. Brancial lamelle indistinctly folded transver- sely on the one side. Incubatory lamelle very narrow. Last pair of uropoda rather elongated, both rami narrow lanceolate and nearly subequal. Telson very short, entire.

Remarks. — The type of this genus is the form described by Sp. Bate and Westwood under the name of Opis qvadrimana, which however shows only a very remote affinity to the Kroyerian genus Opis, wherefore Boeck saw himself fit to establish for it a new genus under the above name. Its distinctive characters are among others the peculiar structure of the anterior gnathopoda, which somewhat resembles that in the young of T’rischi- zostoma, the imperfect development of the palp of the maxillipeds, and the

structure of the last pair of uwropoda and of the telson.

2. Normania qvadrimana, (Sp. Bate & Westwood). (Pl. 13; fig. 1). Opis qvadrimana, Sp. Bate and Westwood, British Sessile-eyed Crust. Vol. If, p. 503.

Body somewhat compressed, with the back evenly vaulted. Cephalon rather deep and nearly as long as the 2 anterior segments of the mesosome combined, lateral corners only slightly projecting but distinctly angular. The 3 posterior segments of the mesosome much larger than the 4 anterior ones. Coxal plates scarcely deeper than the body, rounded inferiorly ; 5th pair con- siderably lower than the preceding ones and almost twice as broad as deep. Lateral corners of the 3rd pair of epimeral plates of the metasome evenly rounded. First segment of urosome not produced dorsally. Eyes large, oval in form. Superior antennee about the length of the cephalon and the 2 ante- rior segments of the mesosome combined, Ist joint of the peduncle not twice the length of the other 2 taken together, flagellum composed of 5 joints only, accessory appendage very slender, triarticulate. Inferior antenne (in female) about the length of the superior, flagellum 4articulate. Anterior gnathopoda with the basal joint very elongated, carpal joint constricted at the base and

forming inferiorly a narrow projecting lobe, propodos large and tumid, rounded

34 quadrate, palm transversely truncated and armed below with 3 strong spines. The 3 posterior pairs of pereiopoda slender and elongate, basal joint broadly oval, dactylus very slender. Last pair of uropoda considerably projecting beyond the preceding one, basal part much longer than the rami. Telson rounded quadrangular, truncated at the tip, a little longer than it is broad. Body whitish, pelucid, with vellowish intestine and dark bluish ovaries, ocular pigment brownish with orange-coloured coating. Length of adult female 5 mm.

Remarks. — The description and figures given by Boeck of this form are rather incomplete and in some cases incorrect, probably owing to his specimen being in a very bad state of preservation. It is the only, as yet, known species of the genus.

Occurrence. — Boeck obtained only a single mutilated specimen of this small Lysianasside at Haugesund on the west coast of Norway. I have myself found it in several places, both on the south and west coast, and generally in rather deep water, especially where the bottom consists of coarse sand and gravel. As the limbs are rather brittle, it is not easy to obtain perfect specimens by the aid of the usual dredge.

Distribution. — British Islands.

Gen. 3. Cheirimedon, Stebbing, 1888.

Body high, compressed, with very large coxal plates. Antenne, of usual structure, subequal (in female). Epistome slightly projecting and defined from the anterior lip by a short incision. Mandibles with the cutting edge terminating exteriorly with an acute dentiform corner, palp originating at about the same level as the molar expansion, less slender than in Normania, with the last joint shorter and furnished with a series of curved sete on the inner edge. First pair of maxille with the palp less expanded and the basal lobe somewhat larger. Lobes of 2nd pair of maxille shorter and broader. Maxil- lipeds rather large, masticatory lobes of moderate size, basal ones normal, palp well developed,” with the terminal joint unguiform. Anterior gna- thopoda prehensile, terminating with a large complanated hand, succes- sively expanded distally; posterior ones less slender than in Normania, propodal joint oval and densely hirsute. Pereiopoda not very slender, basal joint of the 3 posterior pairs very large, serrated posteriorly. Branchial la- melle of usual structure. Uropoda successively decreasing in size posteriorly,

last pair with the basal part rather short and thick, rami very unequal, the

outer one much the larger and haying a distinct terminal joint. Telson large, tapering, and deeply cleft.

Remarks. — This genus, though in some points related to the preceding one is very markedly distmguished by the rather different structure of the anterior gnathopoda and of the maxillipeds, as also by that of the last pair of uropoda and the telson. It was founded by the Rey. Mr. Stebbing

on a species from the «Challenger» Expedition procured at Kereuelen. o 5

3. Cheirimedon latimanus, G. 0. Sars. (PI. 13, fig. 2). Normania latimana, G. O. Sars Oversigt af Norges Crustaceer I, p. 83, pl. 3 fig. 5.

Body highly compressed, with the back evenly rounded. Cephalon haying the lateral corners somewhat projecting and angular. Segments of mesosome successively increasing in size posteriorly. Coxal plates very large, the 4 anterior pairs being more than twice as deep as the body; 5th pair about as deep as it is broad. Epimeral plates of metasome likewise rather large, last pair having the posterior corners rectangular. First segment of urosome pro- duced dorsally to a high compressed projection, obliquely truncated at the tip. Eyes of moderate size, narrow oval. Superior antenne about the length of the cephalon and the 3 anterior segments of the mesosome combined, Ist joint of the peduncle more than three times the length of the other 2 com- bined, flagellum about the length of the peduncle, 7-articulate with the Ist joint rather large, accessory appendage slender, triarticulate. Inferior antenne (im female) about the length of the superior, flagellum 6-articulate. Anterior enathopoda with the carpus very small, triangular, propodos exceedingly large and broad, occupying about the third part of the length of the leg, triangular, gradually expanded towards the extremity, palm without any crenulations,slightly arcuate and defined below by a rightangled corner armed with 2 slender spines. Last pair of uropoda with the basal part shorter than the telson, inner ramus conically tapering and quite bare, outer one haying at the end of the basal joint on each side a short spine. Telson almost twice as long as broad, gradually tapering and cleft beyond the middle, with 2 small dorsal denticles on each side and a single one at the tip of each terminal lobe. Length of adult female 6 mm.

Remarks. — The present species was formerly referred by the author to the genus Normania. But a closer anatomical examination has shown it to be in reality rather different, and evidently to belong to the genus

Cheirimedon, as characterised by the Rey. Mr. Stebbing.

36

Occurrence. — The only specimen met with, an adult ovigerous female, was found many years ago by the author at Bukken on the west coast of

oS

Norway, the depth not recorded.

Gen. 4. Opisa, Boeck, 1876. Syn: Opis, Kroyer.

Body rather robust, with broadly rounded back and very large and deep coxal plates. Antenne in female very short, the inferior ones of male, however, greatly elongated and furnished at the anterior edge of the flagellum with a regular series of «caleeole«. Epistome not very projecting and defined from the anterior lip by a slight sinus. Mandibles of the usual structure, palp originating nearer to the base than does the molar expansion, rather slender, 2nd joint densely setiferous on the inner edge. Maxille about as in Normania. Mavxillipeds with the palp normal but comparatively short, only slightly reaching beyond the masticatory lobes; the latter rather large, oblong, angular at the tip, inner edge denticulated. Anterior gnathopoda prehensile, terminating with a very large forcipated hand, the inferior angle of the pro- podos being produced’ to an unguiform process, against which the greatly curved dactylus admits of being impinged. Posterior gnathopoda of the usual slender form, propodal joint oval, truncated at the tip. Pereiopoda not very elongated, basal joint of the 3 posterior pairs greatly dilated. Branchial lamellae normal. Last pair of uropoda reaching beyond the preceding pair, rami densely setous at the inner edge. Telson very elongated and deeply cleft.

Remarks. — The generic name Opis proposed by Kroyer having been employed in Zoology at an earlier date, Boeck has seen fit to make the above slight change by adding the feminine termination. The genus is chiefly distingnished by the peculiar foreipate character of the anterior gnathopoda. It only comprises as yet a single species; for the several forms referred by

other anthors to this genus have turned out to be in fact generically distinct.

4. Opisa Eshcrichti, (Xréyer). (Pl. 14, fig. 1). Opis Eschrichti, Kroyer, Naturh. Tidsskr. 1 ser. V. 4, p. 149. Syn: Opis typica, Kroyer. Body glabrous, rather thick, with evenly vaulted back. Cephalon rather short, with the lateral corners somewhat projecting and narrowly

rounded. First pair of coxal plates much smaller than the 2nd and partly.

covered by the latter; 4th pair deeply emarginated posteriorly and about twice as deep as the body; 5th pair scarcely broader than it is deep. Last pair of epimeral plates of metasome rounded at the posterior corners. First segment of urosome deeply impressed at the base dorsally. Eyes rather large, oblong, pigment dark brown. Superior antenne scarcely more than twice the length of the cephalon, Ist joint of the peduncle very large and tumid, flagellum about the length of the peduncle, 8-articulate, with the Ist joint very large, especially in the male; accessory appendage rather elongated, b-articulate. Inferior antenne in female scarcely longer than the superior, in male nearly as long as the body. Anterior gnathopoda with the propodos nearly globular expanded, the thumb-like process sharply acuminated. Poste- rior gnathopoda with the propodos about half as long as the carpus and slightly dilated distally. Basal joint of the 3 posterior pairs of pereiopoda very large, rounded oval and nearly as long as the remaining part of the legs. Last pair of uropoda with the rami much longer than the basal part, outer one the longer and haying a distinet terminal jot. Telson about three times longer than it is broad, scarcely tapering and cleft nearly to the base, - each lobe having a terminal and 2 dorsal denticles. Colour whitish with dark brown intestine shining through the integuments. Length 7—8 mm.

Remarks. — As mentioned aboye, this is the only species of the genus as yet known. It has been well described by Kréyer in the Journal above cited and was figured by the same author in the well known richly illustrated work by Gaimard.

Occurrence. — On the coast of Norway I have only met with this form, in a single locality, viz., in the Varangerfjord at Vadso, Finmark, where 2 specimens, male and female, were found at a depth of about 100 fathoms. Dr. Goés and Malmgren have taken it in another locality, viz., at Grotosund in Nordland.

Distribution. — Arctic Ocean: Greenland, in several places; Iceland.

Gen. 5. Acidostoma, Lilljeborg, 1865.

Body very short and robust, with the coxal plates large and deep. Superior antenne rather different in the two sexes, having in male the peduncle greatly inflated andthe Ist joint of the flagellum laminarly dilated and densely beset with long cilia; accessory appendage in both sexes unusually large, nearly as long as the flagellum. Inferior antenne quite similar in the two sexes, rather slender. Oral- parts greatly projecting inferiorly and on the

whole constructed upon a similar type as in Trischizostoma. Epistome applan-

6 — Crustacea,

38

ated and not defined from the anterior lip; the latter narrow and elongated. Mandibles with the masticatory part rather produced and without any trace of a molar expansion; palp slender and almost bare except at the tip. First pair of maxilla with only a very slight rudiment of a palp, masticatory lobe narrowly produced and divided at the extremity imto small unguiform teeth, basal lobe rather small and narrow. Second pair of maxille with both lobes styliform produced. Maxillipeds with the masticatory lobes very large and laminar, palp rather slender but scarcely reaching beyond the latter, terminal joint rudimentary, knob-like. Anterior gnathopoda rather robust but scarcely subcheliform, propodos tapering, without any distinctly difined palmar edge. Posterior gnathopoda slender, with the propodos narrow oblong and densely hirsute. The 3 posterior pairs of pereiopoda unusually robust, with both the basal and meral joints greatly expanded. Branchial lamella normal. Last pair of uropoda extremely small, penultimate pair having the basal part very broad. Telson short and broad, scale-like, more or less incised posteriorly.

Remarks. — This genus has been established by Prof. Lilljeborg chiefly on account of the anomalous structure of the oral parts, which would seem to point to a semi-parasitie lite. In fact the present genus shows in the latter respect an unmistakable accordance with the remarkable parasitic form, Trischizostoma, described above, though differmg in most other points very decidedly. Another rather anomalous feature consists in the sexual difference being here chiefly pronounced in the structure of the superior an-

tenne and not, as usual, in that of the inferior ones.

5. Acidostoma obesum, (Sp. Bate). (Pl. 14, fig. 2), Anonyx obesus, Sp. Bate, Cat. Amphip. Crust. Brit, Mus. p. 74, Pl. XII, fig. 1. 3ody thick and robust, with broadly rounded back. Cephalon com- paratively short, with the lateral corners but slightly projecting and rounded. The 4 anterior pairs of coxal plates very large, more than twice the depth of the body; 4th pair deeply emarginated posteriorly and forming, below the emargination, an acute angle; 5th pair fully as deep as broad. Last pair of epimeral plates of metasome narrowly rounded posteriorly. First segment of urosome slightly impressed at the base dorsally. Eyes rather small, rounded, placed near the lateral corners of the cephalon, pigment light brownish. Superior antenne in female with the 2 outer joints of the peduncle much narrower than the Ist and combined about half its length, flagellum about the length

of the peduncle, 7-articulate, Ist joint comparatively short and scarcely

59

broader than the succeeding ones, accessory appendage only very little shorter than the flagellum, 5-articulate; those of male much more mas- sive, peduncle greatly swollen, with the 2 outer joints nearly as broad as the basal one, Ist joint of the flagellum very large and compla- nated, with the inferior edge arched and densely beset with delicate and slender sensitive hairs. Anterior gnathopoda with the propodos about as long at the carpus, dactylus rather short. The 3 posterior pereiopoda nearly uniform in length, or the penultimate one a little longer, basal joint very large, rounded quadrangular, meral joint, especially in the 2 anterior pairs, greatly dilated. Penultimate pair of uropoda with the basal part much broader than that of the preceding pair and forming at the end posteriorly an angular corner; last pair scarcely half as long as the preceding pair, rami lanceolate, unarmed, the outer one the longer. Telson almost as broad as long, rounded, and cleft beyond the middle. Colour pale orange with light red pigmentary bands across the segments. Length 5 mm.

Remarks. — The form described by the author from the North Atlantic Expedition as <Acidostoma Jaticorne is the male of a nearly related species, which differs, in addition to its much larger size, in the total want of eyes and in a somewhat different form of the last pair of uropoda and of the telson. A female specimen of the same species, measuring. 11 mm in length, was also obtained on the Expedition, but was wrongly referred to the typical form. On the coast of Norway this abyssal species has not yet been found; for the specimen named so in my «Oversigt af Norges Crustaceer» I find on closer examination to be more properly referable to the typical species.

Occurrence. — I have met with the present form rather sparingly on the south and west coast of Norway at moderate depths, from 20 to 50 fathoms. Prof. Lilljeborg has taken it at Molde and Boeck at Haugesund; finally Dr. Lindstrom has procured the species at Farsund.

Distribution. — Coast of Bohuslehn, British Islands, Shetland.

Gen. 6. Ichnopus, Costa, 1853.

Body rather slender and compressed, with the coxal plates of moderate size. Both pairs of antenne with the flagella unusually elongated and com- posed of numerous short articulations. Anterior lip slightly projecting anteriorly as a short rounded lobe, defined from the epistome by a narrow incision. Posterior lip strongly chitinised, with very slender and projecting lateral corners. Mandibles rather strong, cutting edge broad, accessory lobe narrowly

rounded and separated from the latter only by a small sinus, palp originating

at the same level as the molar expansion, rather large, terminal joint tapering to a narrow incurved point. First pair of maxille with the masticatory lobe rather large, densely hairy and armed both at the tip and the inner edge with strong denticulated spines, basal lobe small, palp normal. Second pair of maxille with the lobes rather narrow. Maxillipeds well developed, masticatory lobes very large and broadly rounded at the tip, palp attenuated, with the terminal joint comparatively short. Anterior gnathopoda rather small and attenuated, scarcely subcheliform, propodos tapering, without any distinctly defined palmar edge, dactylus short and curved, pectinate at the base. Posterior gnathopoda much longer than the anterior, propodos not pro- duced at the tip. The 3 posterior pairs of pereiopoda successively increasing in length, last pair rather elongated. Branchial lamelle very large and com- plicated, with a double series of small secondary lamelle arranged in a bipinnated manner. Incubatory lamelle rather narrow but somewhat expanded at the end. Last pair of uropoda rather large, rami lanceolate with the edges denticulated and setous. Telson deeply cleft.

Remarks. — The present genus, established by Costa, is chiefly charac- terised by the unusual length of the antennal flagella, by the comparatively small, not subcheliform, anterior gnathopoda, and by the very complicated structure of the branchial lamelle. From the genus Lysianassa, which seems to be its nearest ally, it, moreover, differs by the deeply incised telson. The genus would seem on the whole to have a southern range. It comprises as yet only 3 species, 2 of which, J. tawrus Costa and J. affinis Heller, are peculiar to the Mediterranean, whereas the 3rd species, LI. spinicornis Boeck, besides in the Mediterranean, is also found on the coast of Norway. ‘Two other speeies have been described as belongning to this genus; but the one, I. minutus Boeck, is only founded on young specimens of I. spinicornis, and the other, I. wmbonatus G. O. Sars, has on closer examination been found not to belong to the present genus.

6. Ichnopus spinicornis, (Boeck). (Pl. 15). Ichnopus spinicornis, Boeck, Crust. Amphip. bor. & arct. p. 18. Syn: Ichnopus minutus Boeck. « calceolatus, Heller. Body rather elongated, with the back rounded. Cephalon comparatively small and haying the lateral corners somewhat projecting and angular, Coxal plates successively increasing in size to the 4th pair, which do not

attain the double depth of the body and have the posterior corners drawn out to an acute angle; 5th pair considerably broader than it is deep. First pair of epimeral plates of the metasome produced anteriorly to a short tooth-like projection; last pair having the posterior angle drawn out to a short uptur- ned point, above which thereisa small sinus defining the latter from a convex expansion of the posterior edge. Eyes reniform, much larger in male than in female, pigment deep red. Superior antenne of female about '/s the length of the body, in male considerably longer, Ist joint of the peduncle very thick and masive jutting out at the end inferiorly as a short spiniform projection, the 2 other joints very short; flagellum furnished in both sexes on the posterior edge with a somewhat alternating series of rather large calceolwe, accessory appendage very slender and composed of about 10 articulations. Inferior antenne in female a little, in male considerably, longer than the superior, flagellum in both sexes furnished anteriorly with a row of similar calceole as on the latter. Anterior gnathopoda with the propodos about as long as the carpus but much narrower, dactylus evenly curved and armed at the base with a dense bunch of delicate spinules. Posterior gnathopoda nearly twice the length of the anterior, propodal joint oval, half as long as the carpal joint and not at all produced atthe tip. Last pair of pereiopoda almost twice the length of the 3rd.. Last pair of wropoda with the rami much longer than the basal part, outer one the longer and having a distinct terminal joint. Telson twice as long as broad, cleft beyond the middle, each lobe bearing a small apical denticle. Colour light greenish, oral region and urosome partly tinged with crimson. Length 17 mm.

Remarks. — The present very handsome species is chietly distingnished by the peculiar supply on the antennal flagella in both sexes of numerous rather large colceole, a character which usually is only particular to the male sex. Moreover the spiniform projection of the first joint of the superior antenne, and the peculiar form of the Ist and last pair of epimeral plates of the metasome afford good distinctive characters.

Occurrence. — It has been found in several places on the west coast ot Norway: Manger, Stavangerfjord, Skudesnes, Bukken, Bejan, in moderate depths, from 20 to 50 fathoms. Its most northern range seems to be the Trondhjemsfjord.

Distribution. — Adriatic (Heller), gulf of Marseilles (Marion).

Gen. 7. Lysianassa, Milne Edwards, 1830.

Body compressed, glabrous; with rather firm integuments and very large coxal plates. Superior antenne having the 2 outer joints of the peduncle more elongated than in most other forms; inferior ones in female scarcely longer than the superior, in male greatly elongated. Anterior lip produced anteriorly to a large linguiform plate defined from the epistome by a very narrow fissure-like incision. Mandibles more elongated than in Ichnopus but otherwise of a rather similar structure, palp very slender originating much nearer the base than does the very small molar expansion. First pair of maxillee with the masticatory lobe not hairy but armed at the tip with den- sely crowded strong denticulated spines, basal lobe rather large, triangular, without distinct apical sete. 2nd pair with the inner lobe much broader than the outer. Maxillipeds well developed, masticatory lobes of moderate size, reguarly oval, palp slender and elongated. Anterior gnathopoda comparatively small, not subcheliform, propodos tapering, dactylus short and simple; poste- rior ones about as in Ichnopus. Pereiopoda rather slender, the 3 posterior pairs with very broad lamellar basal joints. Branchial lamelle indistinctly folded transversely on the one face. Uropoda slender, successively dimin- ishing in size posteriorly, last pair with the rami narrow lanceolate, naked in female, densely setiferous in male. Telson small, squamiform, entire.

Remarks. — This is the genus at first established and may therefore be regarded as the type of the family. It is easily known by the slender compressed form of the body and the largely developed coxal plates. As distinctive characters may, moreover, be named the structure of the anterior gnathopoda and especially that of the telson. The genus would seem to haye an evident southern range and to comprise several species, some of which however, may still be regarded as rather doubtful. Thus the arctic form described by Dr. Goés as Lysianassa cymba and likewise by Boeck mentioned, though with some doubt, as a Lysianassa, can certainly not be adduced to this genus. Only a single species belongs to the Norwegian fauna; for the form described by Boeck under the name of Lysianassa plumosa is quite cer- tainly the adult male of ZL. Coste.

7. Lysianassa Coste, (Milne Edwards). (Pl. 16, fig. 1.) Lysianassa Coste, Milne Edwards, Ann. des Sci. Nat. T. XX, p. 365, Pl. 10, fig. 17. Syn: Lysianassa plumosa, Boeck = 6. Body rather slender and compressed, with the back narrowly rounded.

Cephalon comparatively narrow, lateral angles considerably produced and

acuminate. Coxal plates very large and close together, the inferior edges of the 4 anterior pairs forming on each side an uninterrupted arch, 4th pair the largest and nearly three times as deep as the body, deeply emarginated po- steriorly, the lower part’ considerably dilated and forming posteriorly a sharp corner; 5th pair about as deep as broad. Last pair of epimeral plates of metasome produced at the posterior coner to a sharp upturned hooklike pro- jection. Eyes large, broadly reniform, pigment dark purplish. Superior antenne almost the length of the cephalon and the 2 anterior segments of the mesosome combined, 1st joint of peduncle rather broad, with a row of small delicately ciliated bristles on the posterior edge, the 2 succeeding joints con- siderably narrower and combined about as long as the Ist; flagellum slender, about the length of the peduncle, 12-artieulate; accessory appendage very small, triarticulate. Inferior antenne in female scarcely longer than the superior, 3rd joimt of the peduncle unusually large, flagellum shorter than the peduncle; in male greatly elongated, exceeding the length of the body, flagellum very narrow, filiform. Anterior gnathopoda unusually short, basal jot as long as the whole remainder part of the leg, propodos narrow, tapering, a little longer than the carpus. Pereiopoda densely setous, the sete in female simple, in male plumose, carpal and propodal joint, as well as the dactylus, in all very slender. Last pair of uropoda with the rami scarcely as long as the basal part. ‘Telson oval, unarmed, evenly rounded posteriorly. Colour pale yellowish, with irregular orange shades on the 4 posterior pairs of coxal plates and the posterior segments of the body. Length 12 mm:

Remarks. — It appears to me somewhat doubtful whether the present form is identical with the species so named by Milne Edwards. But as Sp. Bate has identified the British form, which unquestionably is the same as that here deseribed, with Milne Edwards’ species, I think the name proposed by the latter author must be retained for the present form.

Occurrence. — The species would seem to have a similar distribution on the coast of Norway as Ichnopus spinicornis, having been met with only o the west coast: at Christiansund, Sognefjord, Bukken, Mosterhayn, Hange- sund. It occurs in rather deep water, from 50 to 100 fathoms.

Distribution. — British Islands, France, Mediterranean.

Gen. 8. Socarnes, Boeck, 1870. Body less compressed, with rather large coxal plates. Antenne about as in Lysianassa, saving that the accessory appendage of the superior ones

is more developed. Oral parts very like those in the said genus, but the

44

mandibular palp smaller, and the inner lobe of the 2nd pair of maxille narrower, Anterior gnathopoda, as in Lysianassa, simple, not subcheliform; posterior ones with the propodal joint very short, more or less expanded below the dactylus. Pereiopoda less slender, basal joint of the 3 posterior pairs greatly dilated. Branchial lamellae with distinct, though somewhat irre- gularly arranged, secondary lobes on the one face only. Last pair of uropoda with the rami longer than the basal part, the outer one having a distinct terminal joint. Telson rather large, tapering and deeply cleft.

Remarks. — The present genus, established by Boeck, is very nearly related to Lysianassa, both as to the oral parts and the other limbs. The only character which more markedly distinguishes it, is the structure of the telson, which is certainly very different from that im Lysianassa, and for this reason I think it will be suitable to support the genus, the more so, as there are several forms which pretty well agree with each other in the latter character. Besides the species described below, the arctic form, Lysi- anassa bidenticulata Sp. Bate, unquestionably belongs to the same generic type, and in all probability also LZ. Mréyeri White from Van-Diemens Land. Moreover, some of the species of Anonyx described by Heller from the Adriatic

would seem to be more properly referable to the present genus.

8. Socarnes Vahli, (Kroyer). (Pl. 16, fig. 2). Anonyx Vahli, Kroyer, Gronlands Amphipoder 1. ¢., p. 5. Syn: Gammarus ngax, Owen, not Phipps.

Body rather slender but somewhat thickish, with broadly rounded back. Cephalon rather deep, with the lateral corners but slightly produced and narrowly rounded. Coxal plates rather large but scarcely more than twice the depth of the body and comparatively narrower than in Lysianassa; 5th pair nearly as deep as broad. Last pair of epimeral plates of metasome broadly rounded or almost obtusely truncated at the posterior corners. Eyes reniform, pigment black. Superior antenne with the 1st joint of the peduncle about twice the length of the other 2 combined, flagellum about as long as the peduncle, 12-articulate, Ist joint rather small, accessory appendage half the length of the flagellum, 7-articulate. Inferior antennee in female scarcely longer than the superior, in male greatly elongated, exceeding in adult speci- mens the length of the body. Epistome and anterior lp almost exactly as in Lysianassa. Anterior gnathopoda with the basal joimt shorter than the

remainder part of the leg, propodos about the length of the carpus, evenly

45

tapering to the end. Posterior gnathopoda with the propodos scarcely half the length of the carpus, roundly expanded below the dactylus. Last pair of uropoda with the inner ramus considerably shorter than the outer. Telson about the length of the basal part of the last pair of uropoda, cleft beyond the middle, the lobes narrowly rounded at the tip and each armed with a small apical denticle. Body whitish, ornamented with closely set pigment- ary spots of a beautiful crimson colour forming broad transversal bands over the body and partly also down the coxal plates. Length 14 mm.

Remarks. — From the very nearly related arctic form, S. bidenticulatus (Sp. Bate), the present species is easily known, as well by the far inferior size, and by the broadly rounded corners of the last pair of epimeral plates of the metasome. According to the figures given by Hoek of his Socarnes ovalis, which is identical with the above named form, the posterior gnathopoda also differ very markedly from those in the present species by the propodal joint being produced to an angular corner beneath the dactylus.

Occurrence. —- Off the coast of Norway this form is chiefly restricted to the arctic region, occurring rather plentifully along the whole coast of Fin- mark at moderate depths. Occasionally, however, it is also met with on the west coast, as far south as Haugesund (Boeck).

Distribution. — Arctic Ocean: Greenland, Spitsbergen, Iceland, Novaja

Semlja, the Kara Sea.

Gen. 9. Ambasia, Boeck, 1870.

Body rather compressed, with large and deep coxal plates. Eyes with the visual elements imperfectly developed. Antenne (in female) short and stout, about of equal length, antepenultimate peduncular joint of the inferior ones rather elongated, flagellum in both pairs only composed of a very restricted number of articulations. Epistome projecting in front of the anterior lip as a large angular plate. Posterior lip membranous, with the lateral corners narrowly exserted. Mandibles rather strong, cutting edge broad, molar expansion very slight, almost obsolete; palp slender, originating nearer the base than does the latter. First pair of maxilla with the mastica- tory lobe less strong than usual and having a rather limited number of spines, basal lobe very small and rounded, palp well developed. Second pair of maxilla with the lobes nearly equal-sized and not very elongated. Maxillipeds with the masticatory lobe very large, elliptical, palp poorly developed, only

7 — Crustacea,

slightly reaching beyond the latter; terminal joint imperfectly developed, knob-lke. Anterior gnathopoda slender, propodos narrow, tapering, without any distinctly defined palmar edge. Posterior gnathopoda of the usual struc- ture, propodos oval, very slightly produced beneath the minute dactylus. Pereiopoda comparatively short, dactylus very small, basal jomt of the 3 posterior pairs large and laminar. Pleopoda normal. Last pair of uropoda comparatively short, scarcely reaching beyond the preceding pair, inner ramus much smaller than outer. Telson of moderate size, deeply cleft.

Remarks. — The present genus agrees with the 3 preceding ones in the structure of the anterior gnathopoda, but differs materially by the devia- ting form of the epistome, as also in the structure of the oral parts. From Lysianassa it is further distinguished by the deeply cleft telson, and from both that and the other two genera by the poor development of the last pair of uropoda. It may be that the 2 Mediterranean species, Anonya Smarde and filicornis, described by Heller, belong to this genus, as suggested by Boeck, but, on the other hand, I cannot coincide with the Rey. Mr. Stebbing in reterrig to this genus the form he describes from the Challenger Expedition as Ambasia integricauda. For the latter form would seem to differ very ma- terially from the typical species in several characters usually regarded as of generic value, for instance in the form of the telson and especially in the

very anomalous structure of the pleopoda.

9. Ambasia Danielsseni, Boeck. (Qeule aby sites ah). Ambasia Danielsseni, Boeck, Crust. amph. bor. & arctica, p. 17.

Body moderately slender, with the back evenly rounded. Cephalon rather deep, lateral corners produced and almost rectangular. First pair of © coxal plates much smaller than the succeeding ones and partially covered by the same, the latter nearly three times deeper than the body; 4th pair con- siderably dilated inferiorly and exhibiting behind a sharp angular corner; 5th pair about as deep as broad. Third pair of epimeral plates of metasome rounded posteriorly, with a very small upturned dentiform projection at the inferior corners. First segment of urosome provided dorsally with a high compressed triangular expansion. Eyes narrow, subsigmoid, occupying nearly the entire height of the cephalon, pigment a beautiful red. Superior antenne with the Ist joint of the peduncle very large and bulging out anteriorly, the 2 succeeding ones extremely small; flagellum composed of 7 joints, the Ist of which is very large, nearly twice the length of the others combined;

accessory appendage scarcely exceeding the Ist joint of the flagellum,

Bis

AT

5-articulate. Inferior antenne (in female) rather slender, flagellum short, about as long as the penultimate joint of the peduncle, and composed of 5 joints. Anterior gnathopoda having the basal joint slightly dilated and shorter than the remaining part of the leg, propodos scarcely as long as the carpus, dactylus very small. Posterior gnathopoda very slender, propodos about half the length of the carpus. Last pair of uropoda with the outer ramus nearly twice as large as the inner, the latter lanceolate; unarmed. Telson oval, gradually tapering, cleft beyond the middle, the incision very narrow. Colour dark purplish red from numerous pigmentary spots arranged in transversal bands across the segments and continued down the coxal plates and legs. Length 13 mm.

Remarks. — Only female specimens have hitherto been observed. There is, however, every reason to believe that the male would differ from the female in a manner quite analogous to that observed in the genera Lysianassa and Socarnes.

Occurrence. Although very rarely met with, this beautiful Lysia- nassid would seem to occur along the whole coast af Norway. I have found it in several places both on the south and west coast as far north as Hammerfest in Finmark. It is found in depths varying from 40 to 100

fathoms. Out of Norway it has not yet been recorded.

Gen. 10. Aristias, Boeck, 1870.

Body short and thick, with comparatively small coxal plates. Superior antenne rather slender, peduncle narrower than usual. Inferior antennae (in female) shorter than the superior, with the antepenultimate joint of the peduncle short and thick. Epistome scarcely projecting and defined from the anterior lip by a small but distinct sinus. Posterior lip membranous, with short and blunt lateral corners. Mandibles strong, cutting edge quite simple, molar expansion very narrow and prominent, acuminate at the tip, palp rather elongated and attached at the same level as the latter. First pair of maxille with the masticatory lobe very broad and edged with numerous unequal alternating spines, the basal lobe small and rounded, having 5 thick plumose sete on the inner edge; palp normal. Second pair of maxille with the lobes widely diverging, the inner one very broad and strongly incurved, edged with numerous spiniform setee, the outer lobe much narrower and pointing straight forwards. Maxillipeds comparatively small, masticatory lobe oval, palp

48

aa s tapering, almost bare, and but slightly projecting beyond the latter, terminal joint unguiform. Anterior gnathopoda rather robust, propodos tumid at the base, obpyriform and finely serrated on the inferior edge, palmar border not distinctly defined, dactylus short. Posterior gnathopoda very slender and densely hirsute in the outer part, propodos narrow oblong, produced at the tip beneath the rudimentary dactylus so as to form a minute chela. Pereio- poda of nearly uniform size, rather strong, basal joint of the 3 posterior pairs not very much dilated. Uropoda with the rami lanceolate and partly serrated on the edges, last pair slightly reaching beyond the preceding pair, outer ramus the larger and having a distinct terminal joint. Telson comparatively short, deeply cleft. _

Remarks. — This is a very distinct genus, differmg, as it does, espe- cially in the structure of the oral parts, very decidedly from the other Lysia- nasside. Besides the 2 species described below, the Lysianassa ciliata of Heller undoubtedly belongs to this genus, and probably also ZL. hwmilis Costa.

10. Aristias audouinianus, (Sp. Bate). @l: 17, fig. 2). Lysianassa audouiniana, Sp. Bate, Brit. Assoc. Rep. 1855. Syn: Aristias tumidus, Boeck (not Kréyer).

Body short and robust, with broadly rounded back and sharply defined segments. Cephalon very short, truncated in front, lateral corners almost rectangular and shghtly produced at the tip. First pair of coxal plates very small and to a great extent covered by the succeeding pair; the latter only little deeper than the body; 4th pair scarcely broader than 3rd and only very slightly emarginated posteriorly, inferior part narrowly rounded; 5th pair much more broad than deep. Last pair of epimeral plates of meta- some narrowly rounded at the infero-posterior corners, posterior edge smooth. Eyes rounded oval, placed near the lateral corners of the cephalon, pigment black with a whitish coating. Superior antenne about the length of the cephalon and the 3 anterior segments of the mesosome combined, 2nd joint ot the peduncle twice as large as the 3rd, and both together about half the length of the 1st jomt; flagellum only little longer than the peduncle, 10- articulate, Ist jot rather large; accessory appendage half the length of the flagellum, 5-articulate. Inferior antennee having the flagellum about as long as the peduncle and 9-articulate. Anterior gnathopoda with the propodos fully as long as the carpus, inferior edge finely serrated and, besides, armed with 4 short spines. Posterior gnathopoda nearly twice as long as the

anterior and very slender, propodos about half the length of the carpus, both

49

densely setous on both edges. Pereiopoda rather elongated, basal joint of the posterior pair shorter than the remainder part of the leg, meral joint but slightly dilated posteriorly. Last pair of uropoda with the inner ramus distinctly serrated on the inner edge, outer ramus scarcely broader and but little longer than the mner. Telson longer than ‘it is broad, cleft beyond the middle, the incision rather broad, terminal lobes narrow and armed each with 3 small apical spines. Colour corneous yellow with a tinge of flesh-colour on the mesosome, ovaries dark bluish. Length 8 mm.

Remarks. — As recently pointed out by Dr. Hansen, this form has been confounded by Boeck and subsequent authors with the following species. Believing, however, the Lysianassa audouiniana of Sp. Bate to be specifically distinct, he has proposed for the form here described another name, viz., that of A. neglectus. In my opinion, there can be little doubt that in reality both are identical.

Occurrence. — | have met with this form rather plentifully both on the south and west coast of Norway, at least up to the Trondhjemsfjord, in depths varying from 20 to 150 fathoms. Very frequently it is found within the branchial sac of Ascidie, thus leading a semiparasitic life. It is very strange that among the numerous specimens collected not even a single male could be detected. Is it that the sexual difference in this form is so very shght as quite to escape attention?

Distribution. — British Islands, Denmark, France, Shetland; Adriatic

(Heller).

11. Aristias tumidus, (Xvoyer). (Pl. 18, fig. 1). Anonyx tumidus, Kroyer, Naturhist. Tidssk. 2 R., Bd. 2, p. 16. Syn: Menigrates arcticus, Schneider.

Very like the preceding species, but with the body a little more slender. Cephalon with the lateral corners bluntly rounded, not drawn out at the tip. Lateral corners of the last pair of epimeral plates of metasome rectangular, posterior edge irregularly serrated. EKyes comparatively larger than in A. audouinianus, distinctly constricted in the upper part, pigment black. Superior antennee relatively shorter than in that species, flagellum composed of a less number of articulations. Anterior gnathopoda very like those organs in 4. audouinianus, but the propodos comparatively shorter and stouter. Posterior gnathopoda less slender. Pereiopoda also comparatively shorter, propodal joint in all produced at the tip, beneath the dactylus, to a short tooth-like process, meral joint in the 3 posterior pairs considerably dilated, with the

posterior angle produced almost to the end of the carpal joint, basal joint in

50

the last pair fully as long as the remainder part of the leg. Last pair of uropoda with the outer ramus rather large, its basal jomt being considerably dilated and very sharply defined from the small spiniform terminal joint; inner ramus scarcely more than half as long as the outer. Telson about as broad as it is long, cleft beyond the middle, the incision narrower than in A. audouinianus, terminal lobes each with a-single apical denticle. Colour greyish white. Length 8 mm.

Remarks. — Dr. Hansen has been the first to show that, the Kréyerian species Anonya tumidus, which, as above stated, was identified by Boeck and most of the subsequent authors with Lysianassa audouiniana of Sp. Bate, though very nearly related, yet is evidently distinct from the latter, ditfermg, as it does, in several anatomical details very markedly, especially in the structure of the last pair of uropoda. The form described by My. Schneider’) as Meni- grates arcticus is undoubtedly identical with the present species.

Occurrence. — The species would seem on the coast of Norway to be restricted to the arctic region. I have taken it, though rather sparingly, in the Varangerfjord at Vadso in a depth of 60—80 fathoms, and a few speci- mens are preserved in ow Univ. Museum without statement of the locality, but probably also found on the coast of Finmark. According to Gées it occasionally is found m the branchial sac of Ascidiz, as is the case with the preceding species.

Distribution. — Arctic Ocean: Greenland, Spitsbergen, Franz Josephs Land.

Gen. 11. Lysianella, G. 0. Sars, 1882.

Body compressed, shorter and stouter in male than in female, coxal plates rather large. Superior antenne in female comparatively slender, in male much stronger, accessory appendage in both sexes rather elongated. Inferior antenne about as long as the superior, of uniform structure in the two sexes, penultimate joint of the peduncle very large, laminarly expanded and inside densely clothed with fine hair. Buccal mass greatly projecting inferiorly. Anterior lip jutting out in front of the epistome as a narrow digitiform lobe. Posterior lip strongly chitinized, rather narrow, lateral corners but little diverging. Mandibles very strong, but with the molar expansion extremely small, palp unusually short and originating much nearer the base than does the latter. First pair of maxille of usual structure, basal lobe narrowly tapering and provided at the tip with 2 slender bristles; 2nd pair with both lobes narrowly produced and setous only at the tip. Maxillipeds

') Tromso Museums Aarshefter VII.

,

not very large, masticatory lobe narrow oval, basal one acutely tapering, palp slender, setous. Anterior gnathopoda of moderate size, subcheliform; posterior ones rather slender, with the propodos slightly produced beneath the minute dactylus. Pereiopoda slender, basal joint of the 3 posterior pairs very large and laminar. Last pair of uropoda small, scarcely reaching beyond the preceding pair; rami not setous nor denticulate, subequal in size, the outer with a distinct spiniform terminal joint. Telson squamiform, entire. Remarks. — This genus is well characterised by the peculiar laminar form of the penultimate peduncular joint of the inferior antenne, by the digitiform projecting anterior lip, and by the coarse structure of the mandibles. In the form of the telson it agrees with Lysianassa, but is otherwise very different. The sexual differences are somewhat analogous to those described above in the genus Acidostoma, the superior antenne only being modified in the male, and not, as is usual, the inferior. With that genus it also agrees

in the full development of the accessory appendage of the superior antenne.

12. Lysianella petalocera, G. O. Sars. (PI. 18, fig. 2). Lysianella petalocera, G. O. Sars, Oversigt af Norges Crustaceer, I, p. 78, Pl. 3, fig. 3.

Body of female moderately slender, that of male considerably stouter, the mesosome being much shorter in proportion to the metasome. Cephalon in female about the length of the first segment of the mesosome, with the lateral corners somewhat projecting and subangular, in male much deeper and having the lateral corners less projecting. The 4 anterior pairs of coxal plates about twice as deep as the body; 4th pair distinctly emarginated posteriorly with the inferior part considerably dilated; 5th pair scarcely deeper than they are broad. Last pair of epimeral plates of metasome rather large and obtusely rounded at the posterior corner. Eyes oval, dark purplish brown, with a reddish coating; in male considerably larger than in female. Superior antenne in female about the length of the cephalon and the 2 first segments of the mesosome combined; peduncle not very strong, first joint about twice the length of the other two combined; flagellum rather slender, 8-articulate, Ist joint about the length of the 2 succeeding ones combined; accessory appendage a little shorter than the flagellum, but scarcely more slender, 4-articulate. Superior antenne in male much stronger, the peduncle being considerably tumeficated and the 1st joint of the flagellum very large and densely clothed with long sensitive hairs. Inferior antenne with the penultimate joint of the peduncle rounded oval, anterior edge strongly curved, flagellum 8-articulate. Anterior gnathopoda with the propodos rather narrow, about the length of

the carpus, and somewhat obliquely truncated at the tip, dactylus short and simple. Posterior gnathopoda not much longer than the anterior, propodos half as long as the carpus and about of uniform breadth throughout. Last pair of uropoda with the rami scarcely longer than the basal part. Telson rather small, oval, nearly twice as long as broad, and evenly rounded at the tip, with 2 small apical denticles. Colour whitish with greenish intestine; oya in the marsupial pouch orange-coloured. Length of female 5 mm., of male 3!/2 mm.

Remarks. — This is the only as yet known species of the genus; for none of the earlier described forms of Lysianasside can properly be referred to it, at least so far as our present knowledge of them goes.

Occurrence. — Although rather rarely met with, this small Lysianassid would seem to occur along the whole coast of Norway. I first detected it in the Lyngdalsfjord near Farsund, on the south coast of Norway, in a depth of about LOO fathoms, and haye subsequently found it again in several localities both on the south and west coast and even so far North as Mehayn near Nordkap, Finmark. Out of Norway it has as yet not been recorded.

Gen. 12. Callisoma, Costa, 1851. Syn: Scopelocheirus, Sp. Bate.

Body rather thickset, glabrous, with large coxal plates. Superior antennze much shorter than the inferior, with the peduncle considerably tumeficated, Ist joint of the flagellum in male very large, accessory appendage comparatively small. Inferior antenne slender and elongated in both sexes but especially in male, basal joint much tumeficated; flagella of both pairs in male provided with distinct calceolee. Epistome slightly projecting, rounded, and defined from the likewise rounded anterior lip by a distinct sinus. Posterior lip membranous, with widely diverging lateral corners. Mandibles rather powerful, with the molar expansion considerably projecting and tapering towards the tip; palp large and densely setous, originating at about the same level as the latter. First pair of maxille with the masticatory lobe com- paratively short and rounded at the tip, which is armed with numerous unequal spines; basal lobe rather large, triangular, with a series of strong plumose setee on the inner edge; palp of usual structure, apical denticles bifureate. Second pair of maxilla with both lobes short and broad and densely setous, the setee of the inner lobe partly plumose and continued down the inner edge. Maxillipeds with the masticatory lobe comparatively short and

B3

broad, armed on the inner edge with small claw-like spines, basal lobe obtusely truncated at the tip, palp rather large, dactylus slender spiniform. Both pairs of gnathopoda very slender and about of same length, the anterior ones with the propodos narrow and elongated, provided at the tip with a double row of delicate sete, dactylus replaced by a dense brush of hair-like sete, though a claw-like rudiment may be found on closer examination; propodos of the posterior pair produced at the tip beneath the dactylus, thus forming a minute chela. Pereiopoda rather strong, the 3 posterior pairs successively increasing in length; basal joint very broad, lamimar; meral joint likewise considerably dilated, especially im the third pair. Last pair of uropoda considerably projecting beyond the preceding pair, rami subequal, denticulated and setous. Telson elongated and narrow, deeply cleft.

Remarks. — The present genus was established by Costa as early as 1851 for a Mediterranean species C. Hopei, to which was subsequently added by the same author another species C. punctatum. The genus Scopelo- cheirus established by Sp. Bate in 1855 for a British species, is undoubtedly identical with the genus of Costa and thus must cede to the elder name Callisoma. It is a very distinct genus, differing from the other Lysianasside both in the structure of the oral parts and especially in that of the gnatho- poda, the anterior pair of which are very peculiarly constructed. Two closely allied, though evidently distinct, species belong to the Fauna of Norway.

13. Callisoma crenata, Sp. Bate. (Pl. 19, fig 1). Scopelocheirus crenatus, Sp. Bate, Brit. Assoc. Report 1855.

Body rather robust, with broadly rounded back. Cephalon comparatively small, lateral corners but slightly projecting and narrowly rounded. First pair of coxal plates rather broad, completely obtecting at the sides the buccal mass, their anterior and inferior edges forming a quite continuous curve; 4th pair deeply emarginated posteriorly and below the emargination angularly produced; 5th pair much broader than they are deep. Last pair of epimeral plates of metasome rounded at the lateral corners, posterior edge irregularly erenulated. First segment of urosome having dorsally a deep transversal incision, below which there is a rounded carina. Eyes broadly oval, pigment reddish brown with an orange-coloured coating. Superior antenne about twice the length of the cephalon, peduncle short and thick, especially in the male; flagellum 10—12-articulate, Ist joint in female about the length of the 3 succeeding joints combined, in male nearly occupying the half length of the flagellum; accessory appendage 3-articulate. Inferior antenna in female

8 — Crustacea.

5A

twice the length of the superior, flagellum composed of 23—24 joints. Anterior gnathopoda very slender, propodos about the length of the carpus, slightly constricted on the middle. Posterior gnathopoda likewise very slender, pro- podos much shorter than the carpus. Basal joint of 3rd pair of pereiopoda very much dilated and broader than that of the 2 succeeding pairs. Last pair of uropoda with the inner ramus fully as long as the outer and acumi- nated at the tip. Telson very elongated and narrow, nearly three times as long as it is broad, cleft beyond the middle; terminal lobes very narrow and armed each with an apical and a dorsal denticle. Colour yellowish, with numerous orange-coloured pigmentary spots, causing the back to assume a more or less reddish orange hue. Length of adult female 91/2 mm.

Temarks. — This is the species on which Sp. Bate founded his genus Scopelocheirus. It is easily known from most other Lysianasside by its thickish glabrous body densely speckled with orange-coloured pigmentary spots, and by the very conspicuous dorsal incision on the Ist segment of the urosome.

Oceurrence. — I have met with this form in several places both on the south and west coasts of Norway at depths varying from 20 to 100 fathoms. Quite recently I collected it rather plentifwlly in the Trondhjemsfjord from dead fishes fastened on the fishermen’s lines.

Distribution. — British Isles, Shetland.

14. Callisoma Kro6yeri, (Bruzelins). (Pl. 19, fig. 2).

Anonyx Kréyeri, Bruzelius, Skand. Amphip. Gammar. p. 45, Pl. I, fig. 7.

Very like the preceding species, but of smaller size and having the coxal plates less deep. Cephalon relatively somewhat larger, with the lateral corners scarcely projecting. Last pair of epimeral plates of metasome rounded at the lateral corners, posterior edge smooth. First segment of urosome provided dorsally with a similar, though not quite so deep, incision as in C. crenata. Eyes broadly oval, dark brownish. Antenne very like those organs in C. crenata, but with a less number of articulations on the flagella. 3uccal mass distinctly projecting beneath the anterior coxal plates. Gnatho- poda comparatively less slender, propodos of the anterior ones much longer than the carpus and of uniform breadth throughout. Basal joint of the 3 posterior pairs of pereiopoda less dilated than in C. crenata. Last pair og uropoda with the inner ramus a little shorter than the outer, but scarcely

narrower. Telson shorter than in C. crenata, about twice as long as broad,

55

and cleft almost to the base. Colour yellowish, with dark brown intestine and without distinct pigmentary spots. Length of adult female 51/2 mm.

Remarks. — Although very closely related to the preceding species, this form may be readily distinguished, not only by its inferior size, but by the different proportions of the joints of the several legs and by its uniform yellowish colour.

Occurrence. — The only locality in which I have hitherto met with this species is at Bejan, at the entrance of the Trondhjemsfjord. It occurred here not rarely in a depth of 830—40 fathoms.. According to Bruzelius it has also been found on the coast of Finmark.

Distribution. — Coast of Bohuslin (Bruzelius).

Gen. 13. Hippomedon, Boeck 1870.

Body slender and compressed, with rather deep though narrow coxal plates. Anterior part of mesosome (comprising the 4 anterior segments) scarcely as long as the posterior part. Metasome powerfully developed, with large epimeral plates, those of the last pair terminating with a sharp upturned hook-like projection. Cephalon comparatively small; eyes imperfectly developed. Superior antennz with the joints of the peduncle more or less produced at the end anteriorly, flagellum of moderate size with the Ist joit very large, accessory appendage comparatively small. Inferior antenne much longer than the superior; flagellum in both sexes, but especially in the male, very slender and composed of numerous articulations; flagella of both pairs of antenne in male provided with distinct calceole. Epistome not at all projecting. Anterior lip rather small and rounded in front. Posterior lip strongly chitinized, with short and blunt lateral corners. Mandibles short and strong, with the molar expansion rather large and massive, truncated at the tip, palp very elongated and originating nearer the end of the mandible than does the latter. First pair of maxille with the masticatory lobe strongly incurved and only armed with a limited number of denticulated spines, the basal lobe short and oval, with 2 curved plumose sete at the tip; palp with the terminal joint gradually expanded distally and armed at the obliquely truncated tip with a dense series of short spines. Second pair of maxille with the lobes short and broad, the inner one setous both at the tip and the inner edge. Maxillipeds comparatively short, masticatory lobe large, with the inner edge straight and armed with a dense row of blunt denticles; palp robust, only

56

slightly reaching beyond the masticatory lobe; terminal joint claw-like. Anterior gnathopoda very slender, carpus elongated, propodos oblong ovate, palmar edge very oblique and indistinctly defined, dactylus slender. Posterior enathopoda of the usual structure, propodos short, scarcely produced beneath the small dactylus. Pereiopoda rather slender, basal joint of the 3 posterior pairs large and laminar. Branchial lamelle of 3rd and 4th pair provided with a digitiform supplementary ramus and a few short lobes at the opposite side; a 5th pair of small branchial lamelle present. Last pair of uropoda considerably projecting beyond the preceding pair; rami elongated, subequal, not setous, but armed with small denticles on the edges, the outer one with a distinet terminal joint. Telson oblong, deeply cleft.

Remarks. — The present genus, established by Boeck, is well distin- guished from the other Lysianassid genera both by the outer habitus and by several anatomical characters, among others by the very slender form of the inferior antenne and of the anterior gnathopoda. The eyes are imperfectly developed and disappear, as a rule, completely in specimens preserved in aleohol. In the northern Ocean occur 5 species of this genus, + of which are to be described in the following pages, the 5th being the Lysianassa abyssi of Goés. Besides, the Rey. Mr. Stebbing has described 4 species from the Challenger Expedition. The genus Platamon of the latter author is very nearly related to the present genus, only differmg by a somewhat different

structure of the posterior gnathopoda.

15. Hippomedon denticulatus, (Sp. Bate). (PI. 20). Anonyx denticulatus, Sp Bate, Cat. Amphip Crust. Brit. Mus. p 75. Syn: Hippomedon Holbolli, Boeck (not Kréyer).

Body glabrous, compressed, but with the back evenly vaulted. Cephalon scarcely as long as the 2 first segments of the mesosome combined, lateral corners but slightly projecting, acute. First pair of coxal plates much broader than the succeeding pair, and dilated inferiorly so as completely to obtect the buccal mass laterally; 4th pair about twice as deep as the body, forming posteriorly an acute-angled projection; 5th pair comparatively small, broader than they are deep. Last pair of epimeral plates of metasome jutting out posteriorly as a narrow lanceolate upturned projection defined from the posterior edge by a distinct incision. First segment of urosome not forming any dorsal projection. Integuments smooth, without any distinct sculpturing. Eyes narrow, linear, slightly widened below, with no trace of lenses; pigment light red with a few opake white stripes transversally.

Superior antenne with the Ist and 2nd joints of the peduncle produced anteriorly to blunt tooth-like projections; flagellum in female only little, in male nearly 4 times longer than the peduncle, 1st jomt in female as long as the remainder 10 joints combined; accessory appendage scarcely longer than the latter, 3-articulate. Inferior antenne in female more than twice the length of the superior, in male about as long as the body, last joint of the peduncle nearly twice the length of the penultimate one. Anterior gnatho- poda with the basal joint as long as the meral and carpal joints combined, propodos half the length of the former, palmar edge finely denticulated. Dactylus of the pereiopoda scarcely more than half the length of the propodos. Last pair of uropoda with the rami about twice the length of the basal part, terminal joint of the outer ramus very small. Telson nearly twice as long as broad, cleft beyond the middle, the incision very narrow in its anterior part; terminal lobes obtusely acuminate, each with a small apical denticle and another dorsal near their base. Body whitish, pellucid, with a few orange-coloured pigmentary bands dorsally across the segments of the meta- some. Length of female reaching 14 mm., of male 11 mm.

Remarks. — This form has been erroneously identified by Boeck and most subsequent authors with Kréyer’s Anonyx Holbolli, which latter according to the recent statements of Dr. Hansen is a very distinct species not occur- ving out of the arctic seas. The present species is easily distinguished both from the said arctic form and from the succeeding new species by the strong dentiform projections formed by the 2 first peduncular joints of the superior antenne and especially by the peculiar form of the posterior projection of the last epimeral plates of the metasome.

Occurrence. — I have met with this form only on the south and west coasts of Norway. It occurs in comparatively shallow water, from 6 to 20 fathoms, especially on sandy bottom, and buries itself with great dexterity within the loose bottom-deposit. Occasionally it also descends to considerable depths, 60—100 fathoms.

Distribution. — Bohuslin, Denmark, British Isles, France, Mediterranean

(taken by the author at Naples).

16. Hippomedon propinqvus, G. O. Sars, n. sp. (Pl. 21, fig. 1). Very like the preceding species, but of somewhat smaller size. Lateral corners of cephalon narrowly rounded at the tip. First pair of coxal plates not nearly so strongly dilated as in H. denticulatus, and scarcely broader

58

than the succeeding pair. Posterior corner of the last pair of epimeral plates of metasome acutely triangular and not defined from the posterior edge by any incision. First segment of urosome slightly produced dorsally. Integuments very finely and irregularly reticulated. Eyes about as in H. denticulatus. Superior antennz with the joints of the peduncle less produced anteriorly. Inferior antenne with the last joint of the peduncle only very little longer than the penultimate one. Anterior gnathopoda comparatively more slender than in H. denticulatus, basal joint longer than the meral and corpal joints combined. Dactylus of the pereiopoda very slender, nearly as long as the propodos. Last pair of uropoda with the outer ramus a little longer than the inner, terminal joint considerably larger than in H. denticu- latus. Telson comparatively narrower, with 2 or 3 pairs of dorsal denticles, the incision deeper. Body whitish, pellucid, with dark red ovaries, urosome and oral region partly tinged with crimson. Length of adult female 10 mm.

Remarks. —— Although very nearly related to H. denticulatus, this species may at once be distinguished by the less produced peduncular joints of the superior antenne, the narrower anterior coxal plates, and especially by the different form of the posterior projection of the last pair of epimeral plates of the metasome.

Occurrence. — This species seems to have a more northern range than the preceding. The most southern locality where I have met with it is the Trondhjemstjord. On the other hand, it is very common on the whole coast of Nordland and Finmark up to Vadso. It occurs in depths varying from 20 to 100 fms.

17. Hippomedon Holbelli, (Kréyer). (Pl. 21, fig. 2). Anonyx Holbolli, Kroyer, Nat. Tidsskr. 2 R. Bd. 2, p. 6.

Form of body about as in the two preceding species. Cephalon trans- versally truncated anteriorly, the lateral corners being not at all produced. Coxal plates as in H. propingvus. Posterior projection of last pair of epimeral plates of metasome triangular, much shorter than in that species and, as in the latter, not detined from the posterior edge by any incision. First segment of urosome with a very conspicuous compressed gibbous projection dorsally. Integuments very distinctly sculptured with close set delicate longitudinal strie partly anastomosing with each other, the striation being also continued on the peduncle of the superior antenne and partly down the sides of the coxal plates. Eyes with a very conspicuous watchglass-formed lens near the

lateral corners. Superior antenne with the joints of the peduncle not at all

produced anteriorly, accessory appendage 4articulate. Inferior antenne about as in H. propingvus. Anterior gnathopoda with the propodos comparatively shorter than in the 2 preceding species. Dactylus of the pereiopoda rather elongated. Last pair of uropoda scarcely different from those in H. propingvus. Telson, on the other hand, comparatively broader, with the incision less narrowed anteriorly. Length of young male 16 mm.

Remarks. — Although the present species cannot properly be referred to the Norwegian fauna, heving not yet been found out of the polar seas, I have thought it right to describe and figure it here, in order to elucidate more closely, than has been done by Dr, Hansen, the characters by which this form is distinguished both from H. denticulatus and propinqvus. Among these characters the peculiar sculpture of the integuments, the presence of a distinct ocular lens, and the comparatively short posterior projection of the last pair of epimeral plates of the metasome are the most conspicuous. The figures here given are drawn from a specimen procured on the Norwegian North Atlantic Expedition off Jan Mayen. Also the form mentioned and figured by the author in his Report on the Crustacea of the said Expedition, as H. Holbolli, var., must, in spite of the total absence of eyes, be referred to the present species, as the integuments in most of the specimens exhibit a very similar close striation as in the typical form.

Distribution. — Arctic Ocean: Greenland, Spitsbergen, Jan Mayen, the Murman coast, the White Sea, Matotschinskar.

Gen. 14. Orchomene, Boeck, 1870.

Body, as a rule, rather thickset, with the segments of mesosome gradually increasing in size posteriorly, and the coxal plates very large. Last pair of epimeral plates of metasome not produced at the infero-lateral corners, posterior edge more or less coarsely serrated. Superior antenne com- paratively short, with the accessory appendage well developed. Inferior antenne in female about the length of the superior, with the antepenultimate joint of the peduncle rather produced, in male very slender and elongated, with the flagellum filiform and provided, like that of the superior ones, with distinct calceole. Epistome projecting in front of the anterior lip as a more or less prominent rounded lamina, overhanging the anterior lip in front. Posterior lip strongly chitinized, with projecting lateral corners. Mandibles

elongated, with the molar expansion yery small; palp slender, originating

60

much nearer the base than does the latter. First pair of maxille with the masticatory lobe almost transversely truncated at the tip and armed with strong denticulated spines, the basal lobe elongated, tapermg, with 2 small apical setee; palp normal. Second pair of maxille with both lobes elongated and narrow, setous at the tip only. Maxillipeds with the masticatory lobe very large, oval, slightly crenulated on the inner edge, palp comparatively small. Anterior gnathopoda short and stout, subcheliform; propodos truncated at the tip, with a distinctly defined palmar edge; dactylus short and curved. Posterior enathopoda slender, propodos slightly produced beneath the minute dactylus. Pereiopoda comparatively short, basal joint of the 3 posterior pairs very large and laminar. Last pair of uropoda in female scarcely reaching beyond the preceding pair, rami partly denticulated at the edges; in male much larger, with the inner edge of both rami provided with plumose sete. Telson comparatively small, not reaching beyond the basal part of the last pair of uropoda, and more or less deeply incised posteriorly.

Remarks. — The present genus has been established by Boeck in order to include some species formerly referred to the genus Anonyx but differing materially in the structure of the oral parts. The genus would seem to include numerous species from different parts of the Oceans. Besides the 5 northern species here described, 3 new species have been recorded by the Rey. Mr. Stebbing from the Challenger Expedition, 2 of which, however, may more properly be referred to the genus Orchomenopsis to be described in the sequel; and of the several exotic species referred by earlier authors to the genus Anonyx some may perhaps on closer examination be found to

belong to the present genus.

18. Orchomene Batei, G. 0. Sars. (Pl. 22). Orchomene Batei, G. O. Sars, Oversigt af Norges Crustaceer, I, p. 81. Syn: Anonyx Edwardsii, Sp. Bate (not Kroyer). ? Anonyx melanophthalmus, Norman.

Body more slender than in the other species, especially in the male. Cephalon with the lateral corners rather projecting, in female broadly rounded, in male narrow lnguiform. Coxal plates of moderate size, the 4 anterior pairs about twice as deep as the body, 5th pair broader than they are deep. Last pair of epimeral plates of metasome nearly rectangular, posterior edge irregularly and minutely crenulated. First segment of urosome with a slight dorsal indentation at the base, more distinct in the male. Eyes oval or

slightly reniform, much larger in male than in female, pigment (in adult

specimens) dark reddish brown. Superior antenne in female about the length of the cephalon and the 1st segment of mesosome combined, flagellum scarcely longer than the peduncle, 8-articulate, Ist joint as long as the 3 succeeding ones combined, accessory appendage half the length of the flagellum, 5-articu- late. Inferior antenne in male fully as long as the body, with the pedun- cular joints considerably expanded. Epistomal plate narrow linguiform, and considerably projecting in front. Anterior gnathopoda very short and stout, propodos about the length of the carpal and meral joints combined, distinctly tapering distally. Posterior gnathopoda with the propodos very narrow, oblong linear, upper edge provided with unusually coarse spiniform bristles, arranged in several transverse rows. Last pair of uropoda in female with the inner ramus shorter than the basal joint of the outer, simple mucroniform, without any lateral denticles. Telson in female oblong quadrangular, scarcely tapering distally, with 2 pairs of dorsal denticles, posterior incision very shallow and broad; in male considerably more elongate, with the posterior intision much narrower. Body cream-coloured, each segment of the mesosome having a small reddish pigmentary speck at the infero-posterior corners. Length of female 7 mm., of male 8 mm.

Remarks. — I think there can be little doubt that the present form is that described by Sp. Bate as Anonya Edwardsii. That, however, the species so named by Kroyer is very different and even belongs to another genus, viz., Onesimus, was first pointed out by Boeck. But the latter author was certainly wrong in identifying the British form with his Orchomene serratus, and for this reason I found it right in my «Oversigt» to give the species a new name, proposing for it that of O. Batei. 1 am now, however, somewhat uncertain whether the species shortly characterised by Norman in his Shetland Report as Anonyx melanophthalmus may not be this species, in which case the specific denomination proposed by that author ought to be retained. The species in question is easily known from the other forms of this genus, not only by its comparatively small size, but by the less robust form of the body, and by the shallow incision of the telson in the female. The pigment of the eyes is in living specimens dark reddish brown (somewhat lighter in young), but becomes in specimens preserved in spirit almost black.

Occurrence. — I have only met with this form in a few localities off the south and west coast of Norway. In one of these localities (Folgero) it oceurred rather plentifully at a depth of 20—40 fathoms among Ascidie and Hydroide.

Distribution. — British Isles, Shetland (?), coast of France (Chevreux).

9 — Crustacea.

62

19. Orchomene serratus, Boeck. (Pl. 23, fig. 1). Orchomene serratus, Boeck, Crust. Amphip. bor & arctica, p. 35.

Body comparatively robust, with broadly vaulted back. Lateral corners of cephalon considerably projecting and obtusely rounded at the tip, in male much narrower than in female. Coxal plates rather large, the 4 anterior pairs more than twice as deep as the body, 5th pair about as deep as broad. Last pair of epimeral plates of metasome nearly right-angled, posterior edge straight and very coarsely serrated, number of serrations 16—20. First segment of urosome transversally impressed at the base and having behind an evenly rounded dorsal carina. Eyes narrow oval, tapering above, pigment dark brown, with a somewhat lighter reddish coating. An- tenne about as in O Batei. Epistomal plate very like that in the latter species, but somewhat broader and less projecting. Anterior gnathopoda less robust than in the said species, propodos fully as long as the carpal and meral joints combined and nearly of uniform breadth throughout. Basal joint of the 3 posterior pairs of pereiopoda fully as long as the remainder part. of the leg. Last pair of uropoda in female with the inner ramus _ shorter than the basal joint of the outer and armed on the inner edge with 3 dent- icles. Telson broadly ovate, tapering distally, with 38 pairs of dorsal denticles, cleft very narrow and extending to about the middle of the telson. Colour more or less yellowish or ochraceous, with dark brown intestine. Length of adult female 10 mn.

Remarks. — This form, confounded by Boeck with the preceding species, may be easily known from the latter by its much more plumpy body, the narrower lateral corners of the cephalon, the more slender anterior gnatho- poda, but especially by the very coarse serrations of the last pair of epimeral plates of the metasome. It also attains a considerably larger size. than that species.

Occurrence. — The species would seem to occur along the whole coast of Norway up to Finmark in moderately deep water, from 30 to 100 fathoms. Boeck collected it at Skudesnees and Lyngholmen, the latter locality lying in the outer part of the Hardangerfjord.

Distribution. — The Norse Island, Spitsbergen (collected on the Nor-

wegian North Atlantic Expedition); the Siberian Polar Sea (Stuxberg).

eee

20. Orchomene crispatus, (Goés). (Pl. 23, fig. 2).

Lysianassa crispata, Goés, Crust. amphip. maris Spitsbergie, p. 3, fig. 3.

Body very robust and plumpy, with broadly vaulted back. Cephalon comparatively short, lateral corners greatly projecting and acuminated at the tip. Coxal plates very large, the 4 anterior pairs nearly three times as deep as the body and quite concealing laterally the buccal mass, 5th pair fully as deep as broad. Last pair of epimeral plates of metasome rounded at the infero-lateral corners, posterior edge straight and finely serrated throughout. First segment of urosome without any dorsal projection. Eyes very narrow, oblong linear, pigment reddish brown with a Llght orange- coloured coating. Superior antenne with the Ist joint of the peduncle unusually narrow and elongated, almost as long as the whole remainder part of the antenna, flagellum 9-articulate with the Ist joint rather short, acces- sory appendage slender, 6-articulate. KEpistomal plate much broader than in the 2 preceding species, but less projecting, obtusely truncated at the tip. Anterior gnathopoda rather strong, propodos very elongated, much longer than the carpal and meral joints combined, and gradually tapering to the transversally truncated extremity. Basal joint of the 3 posterior pereiopoda very much expanded, that of the last pair almost rectangular in form. Last pair of uropoda with the rami comparatively coarser and broader than in the other species. Telson short and broad, with 2 pairs of dorsal denticles, cleft rather broad and not quite extending to the middle of the telson. Body more or less distinctly flesh-coloured, especially on its anterior part. Length of adult female reaching 12 mm.

Remarks. — Boeck has erroneously identified the present form, detected by Goés, with his O. serratus. As will be seen from the above given diagnosis and the accompanying figures, it represents in reality a very distinct species, differing from O. serratus both as to the form of the body and in several anatomical characters. It is now for the first time added to the Norwegian fauna.

Occurrence. — I have met with this form in a few localities off the west coast of Norway and quite recently also in the Trondhjemsfjord. It oceurs, as a rule, in very deep water, especially in the region of the deep-sea corals, depth from 100 to 200 fathoms.

Distribution. — Spitsbergen (Goés). '

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21. Orchomene pectinatus, G. 0. Sars. (Pl. 23, fig. 3). Orchomene pectinatus, G. O. Sars, Oversigt af Norges Crustaceer, I, p. 80, Pl. 3, fig. 5.

Form of body about as in O. serratus, though perhaps a little more robust. Lateral corners of cephalon acute, less projecting than in O. crispatus. Coxal plates rather large, the 4 anterior pairs about twice as deep as the body; Ist pair considerably dilated below, without however completely concealing the buccal mass laterally, 5th pair somewhat narrower than in 0. serratus. Last pair of epimeral plates of metasome rounded at the infero- lateral corners, posterior edge slightly arched and divided into very coarse and sharp somewhat upturned serrations, 12—16 in number. First segment of urosome produced dorsally to a high compressed projection, sharply angulated at the tip. Eyes narrow, slightly sigmoid in form, with imperfectly developed visual elements; pigment very pale, almost cream-coloured. Superior antenne with the Ist joint of the peduncle very large and tumid; flagellum slender, 12

Epistomal plate of very considerable size and greatly projecting, evenly

13-articulate; accessory appendage about half its length and 6—7-articulate.

rounded in front. Anterior gnathopoda rather slender, propodos only little longer than the carpus and very slightly taperimg distally. Last pair of uropoda with the imner ramus fully as long as the basal joint of the outer, and provided at the inner edge with 4 denticles. ‘Telson very small, with 2 pairs of minute dorsal denticles, cleft extending about to the middle and gradually widening posteriorly. Colour pale greyish white. Length of adult female reaching 12 mm.

Remarks. — Though very nearly related to the two preceding species, this form may at once be distinguished by the impertectly developed and pale coloured eyes, the large and projecting epistomal plate, the very coarse serrations of the last pair of epimeral plates of the metasome, and lastly by the high compressed dorsal projection of the Ist segment of the urosome.

Occurrence. — I first detected this form in the Varangerfjord at Bugo, where a few specimens were collected at a depth of about 120 fathoms. In no other parts of the Norwegian coast have I yet met with it.

Distribution. — North Atlantic: outside the great fishing banks off the N.-West coast of Norway (Stat. 124, 192, 251 of the Norwegian North Atlantic Expedition); Arctie Ocean W of Beeren Eiland (Stat. 312 of same Expedition),

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22. Orchomene amblyops, n. sp. (Pl. 25, fig. 1).

Body a little more slender than in the 3 previously described species. Lateral corners of cephalon but slightly produced and distinctly angular at the tip. Coxal plates rather large, the 4 anterior pairs about twice as deep as the body, 1st pair considerably expanded below and to a great extent concealing the buccal mass laterally, 5th pair about as deep as broad. Last pair of epimeral plates of metasome rounded at the infero-lateral corners, posterior edge sligtly arched and regularly serrated, number of serrations 14—16. First segment of urosome with a very conspicuous triangular hump- like dorsal projection, obtuse at the tip. Eyes oblong oval considerably dilated below, visual elements imperfectly developed, pigment light orange- coloured with a faint whitish reticulation. Antenne almost exactly as in 0. serratus. Epistomal plate, on the other hand, considerably broader and nearly of the same form as in O. crispatus. Anterior gnathopoda somewhat more slender than in O. serratus, propodos longer than the carpal and meral joints combined, scarcely at all tapering, tip transversally truncated. Posterior egnathopoda with the propodos much narrower than in that species, and provided with much coarser spiniform bristles. Pereiopoda comparatively more slender, basal joint of the 3 posterior pairs not nearly so long as the remainder part of the leg. Last pair of uropoda with the inner ramus shorter than the basal jomt of the outer, the latter with 3 rather slender ciliated sete on the inner edge. Telson comparatively small, with 3 pairs of dorsal denticles, cleft extending to about the middle and gradually widening posteriorly. Colour whitish with a faint tinge of yellow on the anterior part. Length of adult female 8 mm.

Remarks. — This new species is intermediate in character between O. serratus and pectinatus. From the former it is distinguished by the com- paratively short and angular lateral corners of the cephalon, the imperfectly developed eyes, and the hump-like dorsal projection of the 1st segment of the urosome; from the latter by the different form of the epistomal plate, the less coarse serrations of the last pair of epimeral plates of the metasome, and by the more blunted form of the dorsal projection of the Ist segment of the urosome.

Occurrence. — 1 have met with this form in a few localities off the west coast of Norway, and, besides, in the Trondhjemsfjord and at Apelveer in Namdalen. It is a true deep-water form, only occurring in greater depths, from 100 to 200 fathoms.

Gen 15. Orchomenella, G. 0. Sars, n. Syn: Orchomene, Boeck (ex parte).

Body more or less plumpy, with large coxal plates. Last pair of epimeral plates of metasome scarcely serrated posteriorly, infero-lateral corners blunt or slightly produced. Superior antenne about as in Orchomene; inferior ones, as a rule, more slender and elongated than the superior, in male scarcely as long as the body. Epistome less projecting than in that genus, and evenly rounded or flattened in front. Mandibles of somewhat coarser structure than in Orchomenc, molar expansion comparatively larger and blunted at the tip, palp slender and not originating so near the base as in the latter genus. First pair of maxille with the masticatory lobe very obliquely truncated at the tip, spines partly lamellar and finely denticulated at one of their edges, basal lobe and palp about as in Orchomene. Second pair of maxille with the lobes less elongated. Maxillipeds with the masticatory lobe comparatively smaller and oblong in form, but the palp, on the other hand, larger. Anterior gnatho- poda rather strong, subcheliform, posterior-ones less slender than in Orchomene ; propodos short, dilated distally and densely hirsute, apex slightly produced beneath the minute dactylus. Pereiopoda comparatively short, basal joint of the 3 posterior pairs large and laminar. Last pair of uropoda in female about as in Orchomene, in male but ‘slightly modified, outer ramus only setiferous. Telson- larger than in that genus, reaching beyond the basal part of the last pair of uropoda, form oblong triangular, cleft very narrow fissure-like.

Remarks. — I have seen fit to establish this new genus, in order to include some small species formerly referred partly to the genus Orchomene, partly to that of Anonya and Tryphosa, but agreeng pretty well with each other in certain structural details, so as to form a natural group, which undoubtedly has its nearest ally im the genus Orchomene. Besides the 4 species described below, the form recorded by the Rey. Mx. Stebbing from the Challenger Expedition as Tvyphosa barbatipes may perhaps more properly be

referred to the present genus.

23. Orchomenella minuta, (Kvéyer). (Pl. 24, fig. 1). Anonyx minutus, Kroyer, Nat. Tidsskr. 2 R. Bd. 2, p. 23. Body short and thick, with broadly vaulted back. Lateral corners of cephalon slightly produced, in female almost right-angled, in male rather narrow and acute at the tip. Coxal plates very large, the 4 anterior pairs

more than twice as deep as the body, Ist pair scarcely expanding below, 5th

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pair deeper than they are broad and forming at the infero-posterior corner a projecting triangular lobe. Last pair of epimeral plates of metasome with the infero-lateral corners a little produced, posterior edge smooth. First “segment of urosome having a slight transversal depression at the base. Eyes oval, somewhat narrowed above, pigment light red. Superior antenne with the 1st jomt of the peduncle rather Jarge, flagellum scarcely longer than the peduncle, 10-articulate, with the 1st jomt about as long as the 3 succeeding ones combined; accessory appendage scarcely half the length of the flagellum, 4—b5-articulate. Inferior antenne in female only little longer than the superior, flagellum 10—12-articulate. Epistome slightly projecting in front of the anterior lip and evenly rounded. Anterior gnathopoda comparatively slender, propodos about as long as the carpus and very slightly tapering to the somewhat obliquely truncated tip. Pereiopoda unusually short, with the dactylus very minute; basal joint of the 3 posterior pairs very large, longer than the remainder part of the leg. Last pair of uropoda with the inner ramus fully as long as the basal joint of the outer, the latter provided (in female) with a single seta on the inner edge. Telson nearly twice as long as broad, cleft beyond the middle, lateral lobes slightly diverging at the tip. Body pale yellowish red, or flesh-coloured, each segment having at the infero-lateral corners a small orange-coloured speck. Length of adult female scarcely exceeding 6 mm.

Remarks. — The present species was first described by Kroyer as an Anonyx and subsequently referred by Boeck to his genus Orchomene. It may be regarded as the type of the genus.

Occurrence. — The species would seem to occur along the whole coast of Norway, but is especially very frequent in the Arctic region, off the coast of Nordland and Finmark, in moderate depths, from 20 to 50 fathoms.

Distribution. — Arctic Ocean: Greenland, Spitsbergen, the Murman Coast, the Siberian Polar Sea (Stuxberg); ? British Isles (Sp. Bate); 2? Ad- riatic (Heller).

24. Orchomenella pingvis, (Boeck). (Pl. 24, fig. 2). 3 Orchomene pingvis, Boeck, Crust. amphip, bor. & arctica, p. 36.

Very like the preceding species in its general habitus, though perhaps somewhat thicker in proportion to its height. Lateral corners of cephalon narrowly rounded at the tip. Coxal plates not fully as deep as in O. minuta, Ist pair distinctly expanded below, 5th pair exbibiting a similar projecting lobe at the infero-posterior corners as in that species. Last pair of epimeral plates of metasome rounded at the infero-lateral corners, posterior edge

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minutely crenulated. First segment of urosome with a distinct and rather deep transversal depression dorsally. Eyes narrow reniform, pigment light red. Superior antenne rather like those organs in the preceding species, but with the Ist joint of the fiagellum comparatively larger, especially in the male. Inferior antenne in female considerably longer than the superior, the flagellum being rather slender and composed of about 15 joints. Epistome searcely projecting in front of the anterior lip, though being defined from the same by a distinct incision. Anterior gnathopoda considerably shorter and stouter than in O. minuta, carpal joint rather short, propodos about twice its length and distinctly tapering to the transversally truncated tip. Pereiopoda comparatively more powerful, with the dactylus much stronger; basal joint of the 3 posterior pairs shorter than the remainder part of the leg, that of the 3rd pair more evenly rounded than in O. minuta. Last pair of uropoda with the inner ramus scarcely as long as the basal joint of the outer, the latter provided in female with 3 sete on the inner edge. Telson regularly tapering distally and cleft beyond the middle, the terminal lobes not at all diverging. Colour whitish. Length of adult female 71/2 mm.

Remarks. — In its general habitus this species shows so great a resemblance to O. minuta as easily to be confounded with it, at least if the specimens examined are preserved in spirits. On a closer examination, however, several well marked characters will be found to distinguish it from that species, among others the narrow reniform eyes, the slender inferior antenne, the much shorter and stouter auterior gnathopoda, the more powerful structure of the pereiopoda, and lastly the form and armature of the last pair of” epimeral plates of the metasome.

Occurrence. — 1 had not myself been aware of this species before Mr. Schneider last year sent me some detail-drawings of a supposed new species of Orchomene found by him in the Malangenfjord, Finmark. On comparing these drawings with the figures and description given by Boeck of his Orchomene pingvis, 1 found so much agreement that I could not but— believe both forms to be identical. Subsequently, on looking over the vast material of O. minuta collected by me at different times and in different places, I succeeded in picking up several specimens of the same form, both males and females, and have now convinced myself that this species is in reality the O. pingvis of Boeck. In what locality my specimens were collected I cannot, however, say with certainty, but believe them to be from the west coast of Norway. Boeck himself found only a single specimen at Mandal, south coast of Norway, and mentions another specimen taken at Lofoten in a depth of 200—300 fathoms.

Distribution. — Siberian Polar Sea (Stuxberg).

25. Orchomenella ciliata, G. O. Sars (Pl. 25, fig. 2). Tryphosa ciliata, G O. Sars, Oversigt over Norges Crustaceer I., p. 81, Pl. 3. fig. 4,

Body comparatively short and stout. Lateral corners of cephalon rather projecting and broadly rounded in female, somewhat narrower in male. Coxal plates of moderate size, the 4 anterior pairs about twice as deep as the body; 1st pair scarcely expanding below; 5th pair about as deep as broad, infero-posterior angle but slightly produced. Last pair of epimeral plates of metasome rounded at the infero-lateral corners, posterior edge smooth. First segment of urosome with a deep transversal depression dorsally. Eyes rather large, oval, widening below, pigment light red. Superior antenne with the Ist joint of the peduncle very large and thick; flagellum only slightly exceed- ing the length of the peduncle and composed in female of 8, in male of 12 articulations, the Ist of which is very large and densely ciliated, especially in the male; accessory appendage scarcely half the length of the flagellum, d-articulate, Ist joint large, slightly dilated and furnished with dense fascicles of slender sete on the lower edge. Inferior antenne in female but little longer than the superior, in male about half as long again. Epistome flattened in front and not projecting beyond the anterior lip. Anterior gnatho- poda rather robust, propodos a little longer than the carpus and slightly ta- pering to the transversely truncated extremity. Posterior gnathopoda not very slender, propodos oval, fully half as long as the carpus and obtusely produced beneath the minute dactylus. Pereiopoda comparatively short; basal joint of the 3 posterior pairs, and especially that of the last pair, rather expanded and nearly as long as the remainder part of the leg. Last pair of uropoda in female with the inner ramus shorter than the basal joint of the outer, tip bidentate, outer one with 3 slender sete on the inner edge. Telson rather broad, triangular, with a single pair of dorsal denticles, cleft very narrow, extending beyond the middle. Colour greyish white, without any distinct pigmentation. Length of adult female scarcely exceeding 5 mm.

Remarks — 1 first described this form as a Tryphosa owing to its general resemblance to the species of that genus. On closer examination of the oral parts I have, however, now found, that it cannot properly be referred to that genus but must be regarded as a true Orchomenella.

Occurrence. — The only place where I have hitherto met with this species is outside the sandy beaches of Jaederen, south coast of Norway. It occurred here rather sparingly in comparatively shallow water together with Bathyporeia pilosa, Lindstrom.

Distribution. — Coast of France (Chevreux).

10 — Crustacea,

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26. Orchomenella groenlandica (Hansen). (Pl. 26, fig. 1.)

Anonyx groenlandicus, Hansen, Malacostraca marina Grénlandiz occidentalis. p. 72, Pl. II, fig. 5.

Body less robust than in the other species of the genus. Lateral corners of cephalon shghtly projecting and subangular at the tip. First pair of coxal plates much smaller than the succeeding ones, tapering inferiorly and haying the anterior edge concaved; the 8 succeeding pairs about twice as deep as the body; 4th pair rather expanded below; 5th pair comparatively small, rounded, more broad than deep. Last pair of epimeral plates of meta- some produced at the infero-lateral corners to a short upturned dentiform pro- jection, posterior edge arcuate. First segment of urosome deeply depressed dorsally, and exhibiting below the depression a projecting carina terminating with a sharp pomt. Eyes oval, widening below, visual elements imperfectly developed, pigment dark red, with an opaque whitish coating. Superior an- tenn with the peduncle short and thick, flagellum nearly twice its length and composed in female of 8, in male of about 14 articulations, the Ist of which is rather large; accessory appendage half the length of the flagellum, articulate, Ist joint longer than the other 3 combined. Inferior antenne in in female scarcely longer than the superior, in male somewhat more elongated, though not nearly twice as long. Epistome considerably projecting in front of the anterior lip, and evenly rounded. Mandibles somewhat stronger than in the other species, but otherwise of a quite similar structure. Anterior gnatho- poda with the propodos as long as the carpal and meral joints combined, ob- long quadrangular, nearly of uniform breadth throughout, palmar edge trans- versely truncated. Posterior gnathopoda rather slender, propodos half the length of the carpus, gradually widening distally and angularly produced be- neath the minute dactylus. Pereiopoda of moderate length, basal joint of the 3 posterior pairs rather large and laminar. Last pair of uropoda in female with the inner ramus nearly as long as the outer, the latter whithout any sete; in male somewhat larger, with both rami setous on the inner edge. Penultimate pair of uropoda in both sexes with the inner ramus indented near the tip and bearing immediately above the indentation a long spiniform seta. Telson oblong oval, nearly twice as long as broad, gradually tapering distally, with 2 pairs of dorsal denticles, cleft very narrow and extending beyond the middle. Colour whitish, pellucid. Length of adult female 7 mm.

remarks. — At first I believed this form to be the Lysianassa Mar- fensi of Goés, exhibiting, as it does, some points of apparent agreement; but, having had recently through the kindness of Prof. Lovén an opportunity of examining the type specimens of the Stockholm Museum, I find the form so

fal

named by Goés to be evidenty different and belonging to the genus Anonyx in the restriction adopted in the present work. That the Anonyx groenlandi- cus of Hansen is identical with the form here described, is beyond any doubt. It cannot, however, by any means be referred to the genus Anonyz, as it differs very materially from that genus in de structure of the oral parts, which on the other hand agrees pretty well with that in the genus Orchomenella. I therefore have referred it to the latter genus, although it would seem to ditter from the other species in afew points, for instance in the structure of the last pair of uropoda in the male.

Occurrence. — Off the coast of Norway this species would seem to be wholly restricted to the arctic region, I have collected it in two places only, viz., at Mehayn, near Nordcap, and at Vardi, in a depth of 20 to 50 fathoms. It is now for the first time added to the Norwegian fauna.

Distribution. — West coast of Greenland (Hansen).

Gen. 16. Nannonyx, G. 0. Sars, n.

Syn: Orchomene, Boeck (ex parte).

Body unusually short and stout, with large coxal plates and poorly developed metasome and urosome. Both pairs of antenn in female very short and subequal in length, with the flagella only composed of a very restricted number of articulations. Peduncle of the superior antenne very tumeticated ; antepenultimate peduncular joint of the inferior ones long and slender. Epi stome not distinctly defined from the anterior lip. Posterior lp comparatively narrow, lateral corners obliquely truncated. Mandibles much elongated, molar expansion very slight, palp comparatively small, originating near the base of the mandible. First pair of maxille with the masticatory lobe almost trans- versely truncated, basal lobe narrowly tapering, witha single apical seta, palp very small. Second pair of maxilla with both lobes elongated and narrow, setous at the tip only. Maxillipeds well developed, with the basal part considerably dilated and exhibiting along the inferior edge a series of strong diverging sete, masticatory lobe very large, oblong oval, slightly crenulated at the tip, basal lobe unusually elongated and narrow, nearly reaching to the end of the masticatory lobe; palp slender, with the terminal joint very small, knob-like. Anterior gnathopoda very robust, meral and carpal joints considerably ex- panded and provided inferiorly with a dense clothing of slender sete, propodos

likewise densely setous, gradually tapering, without any distinct palmar edge,

dactylus extremely small. Posterior gnathopoda slender and only sparingly setous, propodos narrow linear, angularly produced at the tip beneath the mi- nute dactylus. Pereiopoda short and stout, with the dactylus very small, basal joint of the 3 posterior pairs large and laminar. Last pair of uropoda extreme- ly small, rami much shorter than the basal part and nearly bare. Telson small, sqvamiform, entire.

Remarks. —L have thought fit-to establish this new genus soas to include the following small Lysianassid, referred by Boeck to his genus Orchomene, but differing in several points rather markedly so as more properly to be generically separated. The small size of the dactylus on the several legs has given rise to the generic name here proposed.

27. Nannonyx Goésii, (Boeck). (Pl. 24, fig. 3) Orchomene Goésii, Boeck, Crust. amphip. bor. & arct. p 36.

Body rather. thickset, with broadly rounded back. Cephalon much shorter than the Ist segment of mesosome, lateral corners somewhat produced and broadly rounded at the tip. Anterior coxal plates more than twice as deep as the body; Ist pair obliquely truncated at the tip; 4th pair only very slightly emarginated behind, infero-posterior corners obtusely rounded; 5th pair rather large, a little more deep than broad. Metasome scarcely as long as the 3 posterior segments of mesosome combined, last pair of epimeral pla- tes nearly rectangular, posterior edge slightly crenulated. Urosome very short, Ist segment with a hump-like dorsal projection. Eyes of moderate size, oval, pigment dark brown. Superior antenne with the Ist joint of the peduncle very large, fully twice the length of the other 2 combined; flagellum only half the length of the peduncle and composed of 4 articulations only, the ist of which is rather thick at the base and about as long as the other 3 combined, all the jomts provided with unusually coarse sensitive bristles; -access- “ory appendage about half the length of the flagellum and biarticulate. In- ferior antenne rather feeble, with the flagellum about as long as the pen- ultimate peduncular joint and 4articulate. Anterior gnathopoda very power- ful, propodos obpyriform and about the length of the carpus, but much nar- rower. Posterior gnathopoda with the propodos about half the length of the carpus and very narrow. Basal joint of the 3 posterior pereiopoda rounded oval and about as long as the remainder part of the leg, meral joint rather expanded posteriorly. Last pair of uropoda with the inner ramus extremely small, about half the length of the outer and simple mucroniform. Telson

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rounded quadrangular, nearly as broad as long, tip transversely truncated, with 2 apical denticles and 2 small spiniform bristles on each side. Body yellowish, each segment haying a oright orange-coloured transversal band partly extending down the coxal and basal joints of the 3 posterior pairs of pereio- poda; ova in the marsupial pouch dark violet. Length of adult female only 4 mm.

Remarks. — This is the only as yet known species of the genus and was, as above stated, wrongly referred by Boeck to the genus Orchomene.

Occurrence. — I have only met with 2 specimens of this diminutive species, both collected in the same locality, viz., at Folgero, west coast of Norway, in a depth of about 40 fathoms. Boeck collected this form at Hauge- sund in comparatively shallow water between alge. Out of Norway it has not yet been recorded.

Gen. 17. Orchomenopsis, G. 0. Sars, n. Syn: Orchomene, Stebbing (ex parte).

Body more slender than in the 3 preceding genera, with the metasome well developed and the coxal plates successively increasing in size to the 4th pair. Cephalon with the lateral corners obtusely rounded. Last pair of epi- meral plates of metasome likewise evenly rounded, posterior edge smooth. Superior antenne of moderate length, with the accessory appendage well de- veloped. Inferior antennz considerably longer than the superior. | Epistome not at all projecting, anterior lip rounded in front. Mandibles strong, with the molar expansion slightly produced; palp rather large and originating a little nearer the base than does the latter. First pair of maxille with the masticatory lobe obliquely truncated and armed with strong denticulated spines partly of lamellar form, basal lobe narrowly produced, with 2 small apical bristles, palp normal. Second pair of maxillee with both lobes narrowly pro- duced and acuminate at the tip. Maxillipeds about as in Orchomenella. An- terior gnathopoda very powerful, subcheliform; posterior ones with the carpus rather expanded, propodos comparatively short and angularly produced at the tip beneath the minute dactylus. Pereiopoda strong, basal joint of the 3 post- erior pairs moderately expanded. Last pair of uropoda considerably pro- jecting beyond the preceding pair, rami setous on the inner edge. Telson large, triangular, deeply cleft, the incision very narrow, fissure-like.

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Remarks. — This new genus is nearly related to the genus Orchomene, though differing materially by the epistome being not at all prominent, by the very powerful structure of the anterior gnathopoda, and by the much fuller development of the last pair of uropoda and of the telson, finally by the un- armed last pair of epimeral plates of the metasome. In the structure of the oral partsit comes somewhat nearerto the genus Orchomenella. Besides the northern species described in the sequel, 2 of the Challenger species referred by the Rev. Mr. Stebbing to the genus Orchomene, viz., O. musculosus and O. abyssorum, evidently belong to the present genus and perhaps also his 3rd, species, O. excavatus.

28. Orchomenopsis obtusa, G. O. Sars, n. sp. (Pl. 26, fig, 2.)

Body moderately slender with broadly rounded back. Cephalon about as long as the Ist segment of mesosome, lateral corners but slightly projecting and broadly rounded. Anterior coxal plates about twice as deep as the body; Ist pair gradually widening below; 4th pair distinctly emarginated posteriorly and forming below the emargination an obtuse projecting lobe; 5th pair fully as deep as broad. Last pair of epimeral plates of metasome not at all pro- jecting at the infero-lateral corners, the edge forming an even uninterrupted curve. First segment of urosome deeply impressed at the base dorsally and forming below the depression a rounded carina. Eyes rather large, irregularly oval, pigment ligth red. Superior antenne with the Ist joint of the peduncle very large and thick; flagellum of moderate length, 10-articulate, Ist joint large, about as long as the 5 succeeding joints combined; accessory appendage about half the length of the flagellum and 5-articulate, Ist joint as long as the remainder part of the appendage. Inferior antenne rather slender, exceed- ing the superior by about half their length; flagellum composed of about 18 articulations. Anterior gnathopoda very strong, propodos twice the length of the carpus and but very slightly tapering to the transversely truncated ex- tremity, carpus exhibiting below a rounded projecting lobe. Posterior gnatho- poda with the carpus rather broad, bulging out inferiorly, propodos about half its length, widening distally, with the upper edge curved, the lower straight. Pereiopoda rather elongated but powerful in structure, basal joint of the 3 posterior pairs much shorter than the remainder part of the leg. Last pair of uropoda with the inner ramus very little shorter than the outer; terminal joint of the latter very small. Telson about twice as long as broad at the base, regularly tapering distally, with 4 or 5 pairs of dorsal denticles

near the edges and 2 other pairs inside the others; cleft extending somewhat

beyond the middle and not at all widening posteriorly. Colour uniformly whitish. Length of adult female 12 mm.

Remarks. — From the Challenger species described by the Rev. Mr. Stebbing the present form would seem to differ, among other things, by the somewhat less robust structure of the anterior gnathopoda, as also by a differ- ent form and armature of the telson.

Occurrence. — I have only met with 2 specimens of this form, both females. They were collected last summer in the Trondhjemsfjord from a dead fish fastened on a fishing line, which was let down in a depth of about 100 fathoms.

Gen. 18. Tryphosa, Boeck, 1870.

Body comparatively slender and compressed, with rather deep coxal plates, the 1st pair of which, however, are much smaller than the succeeding ones and tapering distally. Last pair of epimeral plates of metasome smooth, nearly rectangular or very slightly produced at the infero-lateral corners. Superior antenne comparatively slender, with well developed accessory ap- pendage. Inferior antenne in female a little longer than the superior, in male scarcely half the length of the body. Epistome forming a rounded lamina projecting in front of the anterior lip. Mandibles of moderate size, molar expansion distinctly developed, palp not very slender and originating at about the same level as the latter, terminal joint oval. First pair of maxille with the masticatory lobe obliquely truncated at the tip, terminal spines crowded together, basal lobe small, obtuse at the tip, with 2 plumose apical sete. Second pair of maxille with the lobes not very elongated and obtuse at the end. Maxillipeds of moderate size; masticatory lobe rather large, ob- long, projecting beyond the antepenultimate joint of the palp; the latter not very strong. Anterior gnathopoda comparatively slender and feeble in struct- ure, carpus elongated, propodos nearly linear, with a well defined palmar edge. Posterior gnathopoda less slender than usual, propodos more or less dilated and densely hirsute, tip scarcely produced beneath the dactylus. Per- elopoda of moderate size, basal joint of the 3 posterior pairs very large and laminar. Last pair of uropoda but little projecting beyond the preceding pair; rami in female generally simple, not setous, in male provided on the inner, edge with plumous sete. Telson rather large, oblong oval and deeply cleft; terminal lobes each with a single apical denticle.

76

Remarks. — In their outer habitus the species of this genus exhibit some resemblance to those of the genus Orchomenella, though the body appears, as a rule, somewhat more slender and compressed. In the structure of the oral parts as also of the 2 pairs of gnathopoda there are, however, well marked differences between the 2 genera. Off the coast of Norway occur no less than 4 well distinguished, though very nearly allied species. Another northern form, produced on the Norwegian North Atlantic Expedition, was wrongly referred by the author to 7. Hérringii Boeck, but constitutes in fact a distinct new species', nearly allied to 7. angulata G. O. Sars, to be de- scribed in the sequel. A second deep water species, 7. pusilla, was described by the author from the same Expedition. Moreover several exotic species have been recorded. Thus Dr Hansen refers, but with some doubt, a very handsome Greenland species, 7’. pulchra, to this genus, and the Rey. Mr. Steb- bing describes 2 species from the Challenger Expedition, viz., 7. barbatipes, and 7’. antennipotens, neither of which, however, inmy opinion can properly be referred to the present genus, the first being apparently an Orchomenella, whereas the latter undoubtedly belongs to the genus Pseudotryphosa, to be de- scribed in the sequel.

29. Tryphosa nana, (Kroyer). (Pl. 27, fig. 1.) Anonyx nanus, Kroyer, Naturh. Tidsskr. 2 R. 2 Bd. p. 30.

Body rather compressed, smooth and polished. Cephalon longer than the Ist segment of mesosome, lateral corners not very projecting and rounded at the tip. Anterior coxal plates more than twice as deep as the body, Ist pair with the anterior edge distinctly concaved, 4th pair obtusely produced posteriorly in their lower part, 5th pair somewhat more broad than deep. Last pair of epimeral plates of metasome rectangular, posterior edge straight. First segment of urosome without any dorsal projection. Eyes of moderate size, oblong oval, pigment light red. Superior antennee about as long as the cephalon and the 2 first segments of mesosome combined, Ist joint of the pe- duncle twice as long as the other 2 taken together; flagellum considerably longer than the peduncle, 9-articulate, with the Ist joint comparatively short and

scarcely longer than the 2 succeeding ones combined; accessory appendage very

1 The said species, which will be described and figured in an appendix to the pre- sent work and for which I propose the name of T. compressa, is chiefly distinguished by the very deep cephalon, the lateral corners of which are considerably projecting though obtuse at the tip, by the very narrow linear form of the eyes, and finally by the con- siderable size and powerful structure of the propodos of the posterior gnathopada.

77

narrow, scarcely half as long as the flagellum and composed of 5 articulations, the 1st of which does not exceed the succeeding ones in length. Inferior an- tennee in female very little longer than the superior, flagellum 9-articulate ; in male about twice the length of the former. Epistomal plate not very pro- jecting, obtusely angular im front. Anterior gnathopoda with the propodos about the length of the carpus, palmar edge nearly transversely truncated. Posterior gnathopoda with the propodos oval, scarcely narrower than the car- pus, dactylus rather strong. Basal joints of the 3 posterior pairs of pereiopoda successively increasing in size posteriorly. Last pair of uropoda with the inner ramus scarcely longer than the basal joint of the outer. Telson oblong oval, with 2 pairs of dorsal denticles, cleft extending far beyond the middle. Body whitish, pellucid, with a few light reddish pigmentary spots. Length of adult female scarcely exceeding 4 mm.

Remarks. — The description of this and the following species given by Boeck in his great work on the northern Amphipoda is in several points incorrect and misleading as regards the specific distinction; on the other hand, he was certainly right in removing both these species from the genus Anonyx and in referring them to a particular genus. The present species, which may be regarded the type of this genus, is easily known from the other species here discribed both by its small size and by the absolute want of any dorsal projection on the 1st segment of the urosome.

Occurrence. — Off Norway the species would seem to be restricted to the south and west coasts. At least it has never yet been met with either off the coast of Nordland or that of Finmark. It ocewrs, as a rule, in com- paratively shallow water, from 6 to 20 fathoms, especially where the bottom is sandy.

Distribution. — Denmark, Bohusliin, Shetland isles (Norman), coast of

France (Chevreux), Adriatic (Heller). —

30. Tryphosa Ho6rringii, Boeck. (Pl. 27, fig. 2.) Tryphosa Horingii, Boeck, Chrust. amphip. bor. & arct. p. 38.

Body less compressed than jn the preceding species, the back being broadly rounded. Cephalon about the length of the Ist segment of mesosome, lateral corners rather projecting and obtusely rounded at the tip. Coxal plates rather large, Ist pair less concaved anteriorly, 4th pair angularly produced posteriorly in their lower part, 5th pair fully as deep as broad. Last pair of epimeral plates of metasome rectangular, posterior edge slightly arched. First segment of

11 — Crustacea.

8

urosome deeply impressed at the base dorsally and haying besides a very conspicuous compressed hump-like projection angularly produced at the tip. Eyes much larger than in the preceding species, oblong oval, somewhat wide- ning below, pigment light red. Superior antenne with the peduncle compara- tively thicker than in 7. nana; flagellum rather slender, about twice the length of the peduncle, 11-articulate, 1st joint larger than in the latter species; ac- cessory appendage half the length of the flagellum, 6-articulate, Ist joint the largest. Inferior antenne in female scarcely longer than the superior, flagel- lum 13-articulate. Epistome considerably more projecting than in 7. nana and rounded in front. Anterior gnathopoda more slender than in the latter species, propodos shorter than the carpus and nearly transversely truncated at the tip, with 2 very conspicuous spines on the inferior corner. Posterior enathopoda likewise rather slender, propodos oblong oval and scarcely as broad as the carpus. Pereiopoda comparatively stronger than in 7’. nana, basal joint of the last pair very large, rounded quadrangular. Last pair of uropoda nearly as in the latter species, though the immer ramus appears a little larger. Telson oblong oval, slightly tapering distally, with 3 pairs of dorsal denticles, cleft very deep, almost extending to the base. Colour pale reddish or carneous. Length of adult female 7 mm., of male 6 mm.

Remarks. — The present species is nearly allied to the preceding one, from which, however, it is readily distinguishable by the very conspicuous triangular projection of the Ist segment of the urosome, as also by the larger size of the eyes.

Occurrence. — Unlike the preceding form this species is a true deep water form, occurring only in greater depths from 50 to 150 fathoms, especi- ally in the region of the deep sea corals. I have collected it in several partes of the west coast of Norway up to Lofoten, as also in the Trond- hjemsfjord.

Distribution. — East coast of North America, Labrador (Packard);

Denmark (Meinert);Bohusliin (Gunhild’s Expedition).

31. Tryphosa angulata, G. O. Sars, n. sp. (Pl. 28, fig. 1.)

Body somewhat shorter and stouter than in the 2 preceding species. Cephalon rather deep, lateral corners distinctly angular and drawn out at the tip to a short anterior directed tooth-like projection. Anterior coxal plates seareely twice as deep as the body; Ist pair distinctly concayved anteriorly,

4th pair angularly produced below the emargination, 5th pair about as deep

79

as broad. Last pair of epimeral plates of metasome rectangular, posterior edge straight. First segment of urosome exhibiting, as in 7. Hérringii, a rather high and compressed dorsal projection, the tip of which, however, is distinctly biangular. Eyes very large, nearly occupying the entire height of the cepha- lon, narrow oblong in form, pigment light red. Superior antennee very slender, with the peduncle narrower than usual; flagellum nearly twice its length setous on the lower edge and 14articulate, Ist joint scarcely as long as the 3 succeeding ones combined; accessory appendage about equalling '/s of the length of the flagellum and composed of 5 articulations, the first of which hardly exceeds in length the 2nd. Inferior antenna in female a little longer than the superior, flagellum 15-articulate. Epistomal plate considerably pro- jecting and quite evenly rounded in front. Anterior gnathopoda of the usual slender form, propodos scarcely as long as the carpus, palmar edge oblique, dactylus with a conspicuous secondary denticle. Posterior gnathopoda with the propodos about as broad as the carpus. Pereiopoda rather slender, basal joint of last pair large, oval in form. Last pair of uropoda with the inner ramus scarcely longer than the basal joint of the outer and provided on the inner edge with a single denticle. Telson oblong oval, gradually tapering distally, with 3 or 4 pairs of dorsal denticles, cleft very narrow, fissure-like, and extending considerably beyond the middle. Colour pale reddish. Length of adult female 7 mm.

Remarks. Though in some points closely agreeing with 7. Hérringii, this pretty species is at once distinguished both from that species and from T. nana by the peculiar angulated form of the lateral corners of the cephalon, as also by several other characters named in the above diagnosis.

Occurrence. — The range of this species would seem to be more north- ern than that of the 2 preceding ones. I have found it rather sparingly in a few places off the coast of Nordland and Finmark and quite recently more plentifully in the Trondhjemsfjord. It is a true deep water species, only oc-

curring in depths varying from 100 to 150 fathoms.

32. Tryphosa nanoides, (Lilljeborg). (Pl. 28, fig 2.) Anonyx nanoides, Lilljeborg, On the Lysianassa magellanica ete., p. 25, Pl. III, fig. 32—84.

Body rather slender and highly compressed. Cephalon scarcely longer than the Ist segment of mesosome, lateral corners but slightly projecting and rounded at the tip. Anterior coxal plates fully twice as deep as the body; Ist pair with the anterior edge straight, 4th pair considerably expanded be-

80

low and angularly produced posteriorly, 5th pair a little more broad than deep, with the posterior edge obtusely angulated on the middle. Last pair of epimeral plates of metasome produced at the infero-lateral corners to a short and blunt point, posterior edge arched. First segment of urosome deeply impressed dor- sally and exhibiting below the depression a rounded carina advancing over the succeeding segment. Eyes rather large, oval or reniform, pigment pale red. Superior antenne with the peduncle rather thick and massive; flagellum scarcely twice as long and 11-articulate, Ist joint very large, about the length of the 5 succeeding joints combined; accessory appendage exceeding half the length of the fiagellum, 10-articulate, Ist jomt cansiderably larger than any of the others. Inferior antenne in female somewhat longer than the superior, flagellum composed of about 22 articulations. Epistome forming a narrow rounded lobe overhanging the anterior lip in front. Anterior gnathopoda of the usual structure, propodos shorter than the carpus and transversely truncated at the tip, inferior corner rectangular. Posterior gnathopoda very slender, pro- podos oblong oval, about half the length of the carpus and scarcely as broad. Pereiopoda slender, basal joint of the 3 posterior pairs very large. Last pair of uropoda larger than usual, inner ramus scarcely longer than the basal joint of the outer, both provided on the inner edge near the tip with a few small sete. Telson oblong oval, very slightly tapering distally, with 3 or 4 pairs of dorsal denticles, cleft very deep and narrow. Body whitish pellucid, with a few scattered patches of a diffuse orange-coloured pigment. Length of adult female 8 mm.

Remarks. — The present species, discovered by Prof. Lilljeborg, is easily distinguishable from any of the preceding ones by the slender compres-— sed body, the form of the last pair of epimeral plates of metasome and by the rounded dorsal carina of the Ist segment of the urosome. Moreover there are in the anatomical details several well marked characters to distinguish this species from the other northern forms of thé genus.

Occurrence. — I have met with this species in seyeral places off the west coast of Norway, as also in Lofoten and off the Finmark coast, in depths varying from 50 to 100 fathoms. Quite recently I collected a great number of specimens in the Trondhjemsfjord from the back of a living skate (Raja batis) just brought up by a fishing line from a depth of about 80 fathoms.

Distribution. — Coast of Bohusliin (Bruzelius); Denmark (Meinert); Shet- land isles (Norman); Greenland (Hansen); off Jan Mayen (Norw. North-Atlantic Expedition).

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Gen. 19. Tryphosites, G. 0. Sars, n. Syn: Typhosa. Boeck, (ex parte).

Body slender, with large coxal plates, the Ist pair of which does not differ in form from the succeeding ones. Last pair of epimeral plates of meta- some produced at the infero lateral-corners to a triangular upturned lobe. Superior antenne slender, with the accessory appendage comparatively small. Inferior antenne in female scarcely longer than the superior. Both pairs of antennee, but especially the 2nd, greatly elongated in male. Epistome _pro- duced in the form ofa lanceolate anteriorly pointing spine. Mandibles of mode- rate size, molar expansion large and well developed, palp slender, originating a little nearer the base than does the latter, terminal joint very narrow. Maxille about as in Tryphosa. Maxillipeds with the masticatory lobe very large, oblong oval, slightly denticulated on the tip and inner edge; palp reach- ing but little beyond the latter, dactylus elongated, claw-like. Anterior gna- thopoda of a similar slender form as in T'ryphosa. Posterior gnathopoda ra- ther elongated; carpus very narrow, linear; propodos large, oblong, dilated at the middle, tip not produced beneath the minute dactylus. Pereiopoda unusu- ally slender and elongated, especially those of the posterior pairs, the basal joint of which is greatly expanded. Last pair of uropoda rather large, con- siderably projecting beyond the preceding pair, rami denticulated and setous in both sexes. Telson deeply cleft, each of the terminal lobes armed at the tip with 3 denticles.

Remarks. — The type of this genus is Anonya longipes Sp. Bate, which was referred by Boeck to his genus Tryphosa, though he remarks that it differs markedly from the other species in the form of the epistome, so as perhaps more properly to be generically separated. Such a separation I think is in fact fully justified, since this form also differs from the species of Try- phosa in several other characters of apparently generical value.

33. Tryphosites longipes, (Sp. Bate). (Pl. 28, fig. 3, Pl. 29 fig. 1.) Anonyx longipes, Sp. Bate. Catalogue of the Amphipoda in the British Museum, p. 79, pl. XII, fig Syn: Anonyx ampulla, Sp. Bate (not Phipps) .

Body rather compressed and of slender and elegant form. Cephalon less deep than usual, lateral corners somewhat produced and acute at the tip. Anterior coxal plates more than twice as deep as the body; Ist pair slightly concayed at the anterior edge; 4th pair considerably expanded below and an-

82

gularly produced posteriorly; 5th pair not very large, much-more broad than deep. Last pair of epimeral plates of metasome with the posterior lobe sharply pointed. First segment of urosome without any dorsal projection. Eyes of moderate size, oval, pigment light red. Superior antenne in female about the length of the cephalon and the 3 first segments of mesosome combined; peduncle not very tumeficated; flagellum more than twice its length and composed of about 18 articulations, the 1st of which is very large; accessory appendage searcely 1/4 as long as the flagellum and 5-articulate. Same antenne in male nearly twice as long, flagellum very slender and composed of about 30. arti- culations. Inferior antennz in female searcely as long as the superior, flagel- lum 15-articulate; in male very elongated, exceeding the length of the whole body, peduncular joints rather dilated, flagellum extremely slender, filiform. Epistomal spine considerably projecting beyond the edge of the anterior coxal plates. Anterior gnathopoda slender and feeble in structure, propodos much shorter than the carpus and nearly of uniform breadth throughout, palmar edge somewhat oblique. Posterior gnathopoda with the propodos a little short- er than the carpus, oblong oval, or nearly fusiform, superior edge straight, inferior one bulging out at the middle. Anterior pereiopoda densely setous on the posterior edge; the 3 posterior pairs, but especially the 2 last ones, extremely slender and elongate, with the propodal joint very narrow, and the dactylus straight and setiform. Last pair of uropoda with the inner ramus longer than the basal joint of the outer, terminal joint of the latter spiniform; penultimate pair with the inner ramus deeply incised near the tip and bear- ing immediately above the incision a slender spine. Telson oblong, only slightly tapering distally, with 3 pairs of dorsal denticles, the middle one rather elon- gated, cleft extending far beyond the middle and gradually widening poster- iorly, apical denticles of each terminal lobe diminishing in length inwards. Body whitish pellucid, with reddish brown intestine; ova in the marsupial pouch orange-coloured. Length of adult female 12 mm; of -male about the same.

Remarks. — This is the only as yet known species of the genus; for none of the earlier described forms of Lysianasside can properly be referred to it, at least so far as our present knowledge of them goes.

Occurrence. — Off the coast of Norway this is one of the commonest Lysianassidee, often occurring in considerable numbers at depths varying from 20 to 100 fathoms. I have met with it in numerous places both on the south and west coast, as also along the whole coasts of Nordland and Finmark up to the Varangertfjord.

Distribution. — Denmark, British Isles, west coast of France (Chevreux);

Mediterranem (found bytte author at Naples).

83

Gen. 20. Pseudotryphosa, G. 0. Sars, n. Syn: Tryphosa, Stebbing (ex parte).

Body rather thickish, with the anterior coxal plates comparatively small and densely crowded together. Metasome powerfully developed, with large epimeral plates. Eyes imperfectly developed. Antenne rather elongated but powerful in structure, inferior ones somewhat longer than the superior, fla- gella provided in both sexes with wery distinct alternating calceole. Epi- stome not projecting in front of the broadly rounded anterior lip. Posterior lip membranous, with narrowly produced. diverging lateral corners. Mandibles rather strong, molar expansion well developed, palp moderately slender and originating at about the same level as the latter. Maxille about as in Z'ry- phosa. Maxillipeds with the masticatory lobe short and broad, scarcely reach- ing the end of the antepenultimate joint of the palp; the latter rather robust, with the terminal jot claw-like. Anterior gnathopoda much stronger than in the 2 preceding genera; propodos rather large, imperfectly subcheliform, the palmar edge being not distinctly defined; dactylus very elongated and curved. Posterior gnathopoda slender, propodos gradually widening distally and not produced at the tip beneath the minute dactylus. Pereiopoda power- fully developed, basal joimt of the 3 posterior pairs large and laminar, suc- cessively increasing in size posteriorly. Last pair of uropoda considerably projecting beyond the preceding pair, both rami lanceolate and setous on the inner edge. Telson large, gradually tapering distally and deeply cleft.

Remarks. —I have felt justified in establishing this new genus to include the remarkable form previously characterized by me under the name of Jch- nopus wumbonatus. The closer anatomical examination of this form, instituted subsequently, has indeed shown it to be very different from Ichnopus and not to be properly referred to any of the previously established genera. Besides this species, the form described by the Rey. Mx. Stebbing from the Challenger

Expedition as Tryphosa antennipotens quite undoubtedly belongs to the same genus.

34. Pseudotryphosa umbonata. G. O. Sars. (Pl. 29, fig. 2.) Ichnopus umbonatus, G. O. Sars, Oversigt af Norges Crustaceer I, p. 79, Pl. 3. fig. 2. Body somewhat tumid, with the back broadly rounded. Cephalon about the length of the Ist segment of mesosome, lateral corners drawn out to an acute point. First pair of coxal plates very small, scarcely deeper than the corresponding segment, and tapering inferiorly; the 3 succeeding pairs somewhat deeper than the body ;, 4th pair deeply emarginated posteriorly and pro-

duced below the emargination to a sharp corner; 5th pair rather large, much more broad than deep, and exhibiting on the middle a very conspicuous trans- versal umboniform eminence. Last pair of epimeral plates of metasome not produced at the infero-lateral corners and nearly rectangular. First segment of urosome without any dorsal projection, but shghtly impressed at the base. Eyes inconspicuous in spirit-specimens. Superior antennee about the length of the 5 anterior segments of mesosome combined; Ist joint of the peduncle elon- gated, more than twice as long as the other 2 combined and of uniform breadth throughout; flagellum of rather coarse structure, about twice the length of the peduncle and composed af about 25 joints, the Ist of which is by far the largest; accessory appendage scarcely 1/3 as long as the flagellum, very narrow, almost setiform, and composed of 6 articulations subequal in size. Inferior an- tenne a little longer than the superior, last joint of the peduncle longer than the preceding one, flagellum more slender than that of the superior and composed of about 23 articulations. Anterior gnathopoda with the propodos about twice as long as the carpus, oblong oval, palmar edge very oblique and scarcely defined below, dactylus about half the length of the propodos. Posterior gnathopoda with the pro- podos a little broader than the carpus and about half its length. Basal joint of the last pair of pereiopoda broadly oval, more than twice as large as that of the ante- penultimate pair. Last pair of uropoda with the inner ramus a little shorter than the outer, terminal joint of the latter rather small. Telson fully twice as long as broad at the base, gradually tapering, with 2 pairs of dorsal denticles, cleft extending far beyond the middle, very narrow, fissure-like. Colour whit- ish. Length of the only specimen procured 11 mm.

Remarks. — 1 have been in some doubt about the sex of the specimen examined and, having not found any distinct incubatory lamelle, have signed it on the plate as a male, thus believing the calceole of the antenne to be a peculiar masculine character. ‘The Rev. Mr. Stebbing has, however, on the plate representing his species Tryphosa antennipotens determined the specimen as a female, though it has the antenne provided with calceole in exactly the same manner as the Norwegian specimen. It would thus appear that in this genus, as is the case with Ichnopus, both sexes are provided with those peculiar appendages. From the Challenger species the present form is easily recognized, not only by the peculiar umboniform eminence of the 5th pair of coxal plates, but also by the absolute want of any dorsal projection of the 1st segment of the urosome.

Occurrence. — The above described specimen was collected many years ago at Hvitingsié, west coast of Norway, from a depth of about 150 fathoms.

Distribution. -— Skagerak (Gunhilds Expedition), 1 specimen collected at a depth of 400 to 420 fathoms.

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Gen. 21. Huryporeia, G. 0. Sars. Syn: Hurytenes, Lilljeborg (not. Férster).

Body large and massive, with comparatively low coxal plates. Cephalon short and broad, only very little produced at the lateral corners and nearly entirely exposed together with the large and protruding buccal mass. Meta- some and urosome both powerfully developed. Eyes with imperfectly de- veloped visual elements. Superior antenne of moderate length, peduncle not very tumeficated, flagellum composed of numerous short articulations; accessory appendage well developed. Inferior antenne in female much longer than the superior, basal joint very large and globular, flagellum slender and multiarti- culate. Epistome not defined from the anterior lip, both together forming a broadly rounded prominence in front of the buccal area. Posterior lip large, membranous, lobes insinuated at the tip. Mandibles very strong, cutting edge broad and straight, molar expansion large and protruding, palp not very elongate, originating nearer the extremity of the mandible than does the latter. First pair of maxilla with the masticatory lobe large and massive, obliquely truncated and armed with strong denticulated spines, basal lobe small, with numerous plumose sete on the rounded extremity, palp very narrow, not ex- panded at the tip. Second pair of maxille with the inner lobe much shorter than the outer, both densely setous. Maxillipeds strong, masticatory lobe broadly oval not reaching beyond the antepenultimate joint of the palp, the latter very large, with the joints considerably expanded and densely setous, terminal joint claw-like. Anterior gnathopoda short and stout, propodos ta- pering distally and having a distinctly detined palmar edge. Posterior gnatho- poda extremely slender, propodos nearly linear and but lttle produced at the tip beneath the minute dactylus. Pereiopoda comparatively short and stout, basal joint of the 3 posterior pairs moderately expanded, meral joint of those legs rather large and angularly produced posteriorly. Last pair of uropoda considerably projecting beyond the preceding pairs, rami foliaceous and densely setous on the inner edge. Telson very elongate, conically tapering distally, and deeply cleft.

Remarks. -— In 1865 Prof. Lilljeborg established this genus to include the remarkable gigantic form described by Milne Edwards under the name of Lysianassa magellanica. The denomination Ewrytenes proposed by him having, however, been before adopted for a genus of Hymenoptera, I have changed the latter half of the compound, still conserving the signification of the name as intended by Prof. Lilljeborg. The genus would seem to combine some characters of the genera Anonyx and Onesimus, still exhibiting a number of characters of its own.

12 — Crustacea.

35. Euryporeia gryllus, (Mandt). (Pl. 39.) 36 Lysianassa gryllus, Mandt, Obseryationes in historiam naturalem in itinere Groenlandico facts 1822. p. 34.

- Syn: Lysianassa magellanica, M. Edw.

Body rather thickset and strongly built, with broadly rounded back and the segments very sharply demarcated. Cephalon shorter than the Ist segment of mesosome, rather tumid, nearly globular, lateral corners very small and narrowly rounded. First pair of coxal plates extremely small, rounded, leaving the lateral faces of the cephalon uncovered; the 3 succeeding pairs successively increasing in size; 4th pair a little deeper than the body, rather expanded below and angularly produced posteriorly; 5th pair nearly twice as broad as deep. Last segment of metasome provided with a very conspicuous dorsal. indentation at some distance from the base, epimeral plates rounded at the infero-lateral corners. First segment of urosome with a similar dorsal in- dentation as in the preceding segment. Eyes irregularly lageniform, bemg con- stricted at the middle and having the inferior part expanded to two diverging lobes; pigment light orange-coloured. Superior antenne about twice the length of the cephalon, Ist joint of the peduncle somewhat longer than the other 2 combined; flagellum nearly three times as long as the peduncle and composed of about 30 articulations, the Ist of which is very large; accessory appendage about half the length of the flagellum and 10-articulate, Ist joint the largest. Inferior antenne nearly twice the length of the superior, last joimt of the peduncle longer than the preceding one; flagellum very slender, densely setous on the posterior edge and composed of about 50 articulations. Anterior gnatho- poda with the propodos longer than the carpus, palmar edge somewhat oblique and defined below by a well marked angle. Posterior gnathopoda fully twice the length of the anterior; propodos somewhat shorter and much narrower than the carpus, both densely setous. Pereiopoda with numerous tufts of small sete on the edges; basal joint of 3rd pair very broad, nearly elliptical in form, that of the 2 posterior pairs more regularly oval; meral joit in both these and the 5rd pair very large and expanded, terminating posteriorly with a pointed deflexed lobe. Last pair of uropoda with the inner ramus somewhat shorter than the outer, terminal joint of the latter very small, aculeiform. Telson nearly extending to the tip of the last pair of uropoda, conico-acuminate in form, and without any denticles, cleft extending far beyond the middle, very

narrow, fissure-like. Colour! rosy with a yellowish tinge, edges of the

' According to the statements of Dr. E. Chevreux

| -~I

legs beautifully vermilion-coloured. Length of an adult female specimen 62 mm.

Remarks. — There cannot now, I think, be any doubt that this form is in reality identical with the Lysianassa magellanica of Milne Edwards, al- though the occurrence of one and the same species both in the Arctic and Ant- arctic seas would seem to be highly perplexing. The recent discovery of this species, during the American Expedition of «Albatross» and the French Ex- pedition of «Hirondelle», in the great deeps of the Atlantic at intermediate latitudes would seem still more to confirm the correctness of the above identi- fication. f

Occurrence. — All the specimens preserved in our Museum have. been extracted from the stomach of large sharks (Seymnus borealis), and as some of these sharks notoriously were captured off the coast of Finmark, the species may properly be referred to the Norwegian fauna, though it probably lives outside the great fishing banks. Through the kindness of Mr. Schneider, cura- tor of the Tromsé Museum, I have had an opportunity of examining 2 speci- mens procured by him, both of which were in an excellent