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' P) t) ’ : f 7 i hi : ns | oe - 7. é » a : 7 . . : 7 i 7 , : 7 - 7 a) : ; ’ 7 : : , . ' ; : 7 : ae! - - ve RY ay 7 i a f - ; f : = | i 7 7 _ | a - 7 ry i ' a a : oe 7 a : 7 i, : 1% - ' . . a ; : oP > = 7 7 ) ‘ » ; 7 a 7 i - i 7 1 7 _ ; Fi | a ny - : AL a. < vas — - ‘a ; -_ : ; ; : i a ; : - Vi 7 : - m7 7 i 7 1 n> - \ § a 7 ; P : ’ a) 7 of : '~ ; oY it, : ; : 7 aa ve ; 7 ? — Eg D! _ @ ae - ‘= a a > |e ¢ _ ty ml a @ « : - fi > —— a 7 = a ie _ 7 7 _ Ve r 7 ¥ a> “o>.” —_— : ’ - i : fi ; a —aP a ¢ ‘| i -_ °- 7 7 if oe 7 7 = On _ 2 “« 2 a ‘ 7 ’ _ Sa ard q ys DESORPTION 4 AND. FIGURES OF ALL THE SPECIES @. O. SARS. sa Ah wh te! i ¢ ba 4 . 4 VOL. 1. y : = av. @ vo a , mm - n 7 ‘a : . : 7 : ‘b) - > 7 i a : 1] a . 7 ay Ca me £. : " in a nl - mi on - wae zg. »S ' a ¥ ve , “e 2 r Gs T ' @ »° oa ‘ ’ 7 aay ov, bp 7 ~ e : \ 7 7 a ! Lariat 7 : ‘i “§ a, Yi> ? 7 d . ¥ ——- 7 ti 7 7. 7 Aj t - i wl S a 4 ; is 7; . : ‘ i< DAS aly , Y ; 4 ! ar oar BS 7! i 2 1A 2 + 7 , i : - olay . hat - . ny — moe meg 4 7 Di ’ ‘ : ie oc a ate - _ uy 7 J _—) - "em Aa : 7 - 7 a f; , : : ¥ ‘ ' : - 7 : 3 7 1 7 i ‘ H Y Y 7 1 Wy = 7 us 7 as i a : ’ ' - 7 : _ 7 Ln a ay se YY 7 et ; > 7 ’ - ¥ ‘ > eS 7 : oi 1 - 6 - “7 | 3 Oy a ug 7 ; 7 -) m7 : i : ' \¢ x au i. i - a ; q on i a ; 7 a ; : | : / a i Ay ’ - 7 : : v1 1 a 1 7 and i he | nl : : _ A - . 2 ‘ Ol —_ oe y = vr aa ' . | oa ° a. y y 4 an : ; f | fl Vian, _ a 7 7 al om ! : i i Aa, ; i 7 7 ’ a ; re 7 i me Aa 7 " 1 i <-> ere : iy ’ 7 | 4 ws ao ' > Re as > a =) : : ; Dy i v) we = —— ’ : ; -) 4 pee > -_ an) ‘. . _— _ - : a 7 7 ’ _& 7 - 7 4 P Wel oh ¥ . , + a om b A q ee 7 > ; ’ a i : : rn Wa . ‘ + oi: ‘| fh) 7« i nu wr : - “74% i 7] ; 7 i ? > "i \ in “i a © mY, | nA : i lo 7 - i >; \s t : 7 7 ne vad Flak ia \ Sees o>) i ae ; » [ 7 aa aa 7 oo la n 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 » . details it otherwise exhibits a very close relationship to H. similis. 98 : Occurrence. — I have met with this species in 2 widely distant locali- ties, viz., in the inner part of the Hardangertjord, at Utne, and in Trondhjems- fjord at Vennees, in both places at a very considerable depth. In the last named locality numerous specimens, both male and female, were collected from a dead fish fastened on a fishing line, let down in a depth of about 150 fathoms. It here occurred in company with 2 other species of the genus, viz., H. cicada and H. acutus, and could with the greatest ease, even by the naked eye, be distinguished from either of these species, on account of its whitish eyes and somewhat different coloration of the body. No intermediate forms between the above described very closely allied species have as yet occurred to me. 43. Hoplonyx caeculus, G. O. Sars, n. sp. (Ble 35; figs 1) Body vather slender and compressed. Cephalon considerably longer than the Ist segment of mesosome, lateral corners produced to an acute rather projecting point. Anterior coxal plates about twice as deep as the body; Ist pair scarcely tapermg below; 4th pair with the posterior expansion short and broad, obtusely truncated at the tip; 5th pair comparatively small, about as deep as broad. Last pair of epimeral plates of metasome considerably produced at the lateral corners, forming an acuminated projection. First seg- ment of urosome distinctly depressed at the base dorsally and exhibiting behind the depression a rounded carina. Eyes wholly wanting, not even the slightest trace of pigment being present in the living animal. Superior antenne about the length of the cephalon and the 2 first segments of meso- some combined, flagellum not nearly attaining twice the length of the peduncle and composed of about 11 articulations, the Ist of which is very large, about equal in length to the 5 succeeding ones combined; accessory appendage exceeding half the length of the flagellum, very slender and 4+-articulate, Ist joint larger than the other 3 combined. LEpistome scarcely projecting im front of the anterior lip, though being defined from the latter by a distinct inden- tation. Anterior gnathopoda of the usual slender form, though the ischial joint appears somewhat less elongated than in the other species, propodos about the length of the carpus, palmar edge very oblique, finely denticulated and detined below by an obtuse angle. Posterior gnathopoda with the pro- podos oblong oval, considerably exceeding half the length of the carpus, pal- mar edge transversely truncated. Pereiopoda rather slender, with the dacty- lus long and narrow, the 2 posterior pairs of about equal length; basal joint 99 of the last pair very large, oval, fully as long as the remainder part of the leo. Last pair of uropoda with the rami very narrow, mucroniform, and without any marginal sete, the outer one being the longer and haying the terminal joint spiniform. Telson not nearly twice as long as broad, with 1 or 2 pairs of dorsal denticles, cleft extending nearly to the base. Body pellucid whitish, without any pigmentation. Length of female 5 mm. Remarks. —1 at first believed this little form to belong to the follow- ing genus. Having, however, made out its anatomy in detail, I find it to be a true Hoplonyx, though differing in some points, especially as to the structure of the last pair of uropoda and the absolute want of eyes, rather markedly from the other species. Occurrence. — I haye as yet only met with 2 specimens of this small species, both being collected in the same place, viz., at Lexvigen, Trond- hjemsfjord, from a depth of nearly 150 fathoms. Gen. 24. Centromedon, G. 0. Sars, n. Syn: Anonyx, Lilljeborg (ex parte). Body, as a rule, short and stout, with rather deep coxal plates. Lateral corners of cephalon acutely produced, as also those of the last pair of epimeral plates of metasome. Eyes imperfectly developed or quite want- ing. Antenne (in female) rather stout and subequal in length. Epistome not at all projecting. Anterior lip large and broadly rounded. Mandibles of moderate size, molar expansion conico-attenuated, palp rather large and originating much nearer the tip than does the latter. First pair of maxille with the terminal joint of the palp scarcely expanded at the tip and only armed with a restricted number of spines; 2nd pair with the inner lobe more elongate than in the 2 preceding genera, though a little shorter than the outer. Maxillipeds less strong, masticatory lobe oblong oval, not reaching to the end of the antepenultimate joint of the palp; the latter having the ter- minal joint comparatively small and scarcely claw-like. Anterior gnathopoda rather stout, imperfectly subcheliform; the propodos obpyriform, without any distinctly defined palmar edge; dactylus of moderate length and simple. Posterior gnathopoda more slender than the anterior, propodos transversely truncated at the lip, dactylus small. Pereiopoda moderately slender, basal 100 joint of the 3 posterior pairs large and laminar; last pair considerably shorter than the 2 preceding ones. Last pair of uropoda rather small, only slightly reaching beyond the preceding pair, rami without any marginal sete. Telson oblong, deeply cleft, each terminal lobe with 2 apical denticles. Remarks. — The present new genus is founded upon the small Lysi- anassid described by Prof. Lilljeborg as Anonyx pumilus, which on a closer examination of the anatomical details shows a number of well marked difte- rences from the 2 preceding genera, so as more properly to be regarded the type of a separate genus. The 2 species described by the writer from the Norwegian North Atlantic Expedition as Anonya calcaratus and Anonyx typhlops would seem to belong to the same genus, as also a 3rd species pro- cured on the same Expedition, which is still more nearly allied to C. pumilus, but which at that time was wrongly confounded with the latter species. The generic name here proposed refers to the spiniform produced last pair of epimeral plates of metasome. 44. Centromedon pumilus, (Lilljeborg). (Pl 34, fig. 2) Anonyx pumilus, Lilljeborg, On the Lysianassa magellanica etc., p 26, Pl. IV, figs. 35—41. Syn: Lysianassa producta, Goés. Body very short and robust, though somewhat compressed, with highly curved back. Cephalon about the length of the Ist segment of mesosome, lateral corners drawn out to a sharply pointed straight spine. Anterior coxal plates nearly 3 times as deep as the body and rather narrow, the 3 first having each at the infero-posterior corner a small dentiform projection; Ist pair slightly tapering below; 4th pair with the posterior expansion rather short and nearly transversely truncated at the tip; 5th pair about as deep as broad. Last pair of epimeral plates of metasome produced at the lateral corners to a sharp upturned spiniform lobe. First segment of urosome slightly impressed dorsally and having behind the depression a small rounded carina. Eyes altogether wanting. Superior antenne a little shorter than the cephalon and the 2 first segments of mesosome combined; peduncle not very tumeficated, Ist jomt about twice the length of the other 2 combined; flagellum scarcely attaining the length of the peduncle and composed of 8 articulations only, the Ist of which about equals in length the 2 succeeding ones taken together; accessory appendage half the length of the flagellum and 3-articulate. In- ferior antenne scarcely longer than the superior, flagellum 9-articulate. Anterior gnathopoda with the propodos about the length of the carpus, — 101 tapering distally, inferior edge with a slender spine beyond the middle. Posterior gnathopoda with the propodos exceeding half the length of the carpus, oblong oval in form. Anterior pereiopoda slender, with the propodal joint very narrow and the dactylus much elongated. Posterior pereiopoda rather unequal in length, the penultimate pair being by far the longest; last pair considerably shorter than the antepenultimate one and having the basal joint very large, rounded quadrangular in form, and much longer than the remainder part of the leg. Last pair of uropoda with the inner ramus much shorter than the outer, terminal joint of the latter nearly as long as the basal one and spiniform. Telson gradually tapering distally and having 1 or 2 pairs of dorsal denticles, cleft very narrow and extending far beyond the middle, outer apical denticle longer than the inner. Colour (according to Boeck) whitish with a faint reddish tinge at the end of each segment and of the joints of the antenne and legs. Length of adult female scarcely exceed- ing 5 mm. j : Remarks. — The present species is easily distinguished from the two forms described by the author from the Norwegian North Atlantic Expedition. The above mentioned third not yet described species, for which I would propose the name of C. affinis, differs from the type species, not only by its much larger size, but also by the lateral corners of the cephalon ‘being not straight but slightly upturned at the tip, and by the posterior projection of the last epimeral plates of the metasome being considerably nar- rower and more produced. Occurrence. — I have met with this form only very sparingly in a few localities off the West coast of Norway, as also off the coast of Nordland and Finmark, in depths varying from 50 to 100 fathoms. Prof. Lilljeborg found it at Molde, Boeck at Haugesund, and Mr. Schneider at Tromsé. Distribution. — Arctic Ocean: Spitsbergen (Goés), the Murman Coast (Jarzynsky), the Kara Sea (Hansen), the Siberian Polar Sea (Stuxberg); Bohusliin (Lovén); East coast of North America (Packard). Gen. 25. Alibrotus, Milne- Edwards, 1840. Syn: Onesimus, Boeck, (ex parte). Body rather slender and compressed, with not very large coxal plates. Both pairs of antenne unusually elongated, with the flagella very slender and composed of numerous short articulations; those of the male but little longer than in female and without distinct calceole. Epistome not distinctly 14 — Crustacea. 102 defined from the anterior lip, both together forming a rounded prominence in front of the buccal area. Posterior lip membranous, with the lobes slightly emarginated at the tip. Mandibles rather strong, the molar expansion nar- rowly truncated at the tip, palp very large and originating a little nearer the tip than does the latter. First pair of maxille with the masticatory lobe large and obliquely truncated; basal lobe small, bisetose; palp compara- tively short. Second pair of maxilla with the inner lobe only half the length of the outer. Maxillipeds well developed, masticatory lobe oblong oval and not reaching tothe end ofthe antepenultimate joint of the palp, the latter large and robust with the joimts rather expanded, terminal joint claw-ike. Anterior gnatho- poda unusually strong, propodos considerably expanded and having a dis- tinctly defined palmar edge. Posterior gnathopoda slender, with the propo- dos slightly produced at the tip beneath the small dactylus. Pereiopoda slender and elongate, basal joint of the 3 posterior pairs moderately expanded. Last pair of uropoda reaching considerably beyond the preceding pair, outer ramus setous on the inner edge. Telson short and broad, squamiform, entire. Remarks. — It may perhaps be somewhat doubtful whether the form Lysianassa chausica, wpon which Milne-Edwards founded his genus Alibrotus, is in fact congeneric with the northern species described in the sequel. But as Sp. Bate believes this to be the case, I have thought it right to adopt the generic name proposed by Milne-Edwards. In my opinion Anonyx littoralis of Kréyer cannot, as suggested by Boeck, be referred to the same genus as Anonyx Edwardsii and plautus of the said author, and thus the genus Onesi- mus of Boeck may properly be restricted to the two last named Kréyerian species. From that genus the present is chiefly distinguished by the much more elongated and slender antenne, by the unusually powerful structure of the anterior gnathopoda and by the fuller development of the last pair of uropoda, 45. Alibrotus littoralis, (Kvdyer). (Pl. 35, fig. 2.) Anonyx littoralis, Kroyer, Nat. Tidsskr. 2den Reekke, Bd. 1, p. 621. Body glabrous, curved and rather compressed. Cephalon about the length of the Ist segment of mesosome, lateral corners only slightly projecting and narrowly rounded at the tip. First pair of coxal plates rather large and much expanded distally, anterior and inferior edges forming together an even curye; the 2 succeeding ones much narrower and scarcely twice as deep as the corresponding segments; 4th pair likewise unusually narrow and but very shgthtly expanded in their lower part; 5th pair rounded quadrangular, more 103 broad than deep. Last pair of epimeral plates of metasome nearly rectangu- lar, lateral corners drawn out to a very short point. First segment of uro- some slightly depressed dorsally. Eyes comparatively small, rounded oval, pigment red. Superior antenne in female about the length of the cephalon and the 4 anterior segments of mesosome combined; 1st joint of the peduncle more than twice as long as the other-2 taken together; flagellum very slen- der, nearly 3 times as long as the peduncle and composed of about 26 arti- culations, the 1st of which is by far the largest; accessory appendage scarce- ly exceeding */1 of the length of the flagellum and 5-articulate, Ist joint longer than all the others combined. Inferior antenne a little longer than the superior, basal joint large and globular, flagellum composed of about 30 articulations. Both pairs of antenne in male having the flagella somewhat longer than in female and composed of a much greater number of articulations. Anterior gnathopoda very powerful, propodos rather broad, quandrangular, and longer than the carpus; palmar edge somewhat oblique and armed with several denticles, 2 of which placed below are larger than the rest; dactylus rather strong and quite simple. Posterior gnathopoda with the propodos about half the length of the carpus and oblong in form. Anterior pereiopoda rather powerful, with the propodal joint curved and the dactylus unguiform; posterior ones much more slender, penultimate pair the longest and having the propodal joint very elongate and narrow. Last pair of uropoda with both rami broadly lanceolate, the inner a little shorter than the outer. Tel- son rounded, scarcely more long than broad, tip very slightly emarginated in the middle and haying 2 small denticles. Colour whitish. Length of adult female 13 mm. Remarks. — The present form, originally described by Kréyer as an Anonyx, was subsequently, as stated above, referred by Sp. Bate to the genus Alibrotus of Milne-Edwards on account of the unusually elongated antenne and the powerful structure of the anterior gnathopoda, in which respect. it certainly differs rather markedly from the genus Onesimus, to which it was more recently referred by Boeck. Occurrence. — I have not myself met with this form off the coast of Norway. But Dr. Goés records its being found by Prof. Fries in the Varan- gerfjord, Finmark. Quite recently, too, Mv. Schneider told me that he had procured this form rather plentifully in the neighbourhood of Tromsé by sifting the muddy sand at the low water mark. It thus may in fact be regarded as a true littoral form, burying itself in the loose shingle whilst the water retreates. In the Polar Sea it has often been observed in great abundance at the very surface of the water. 104 Distribution. — Arctic Ocean, widely distributed: Greenland, Spitsber- gen, Franz Josephs Land, the Kara Sea, the Sibirian Polar Sea, off Jan Mayen (Norw. North Atlantic Expedition). Gen. 26. Onesimus, Boeck, 1870. Body rather thickset, with the coxal plates of moderate size, and the last pair of epimeral plates of metasome distinctly produced at the lateral corners. Antenne in female not very slender, the inferior ones generally a little longer than the superior; in male considerably more elongate and both provided with distinct calceole. Epistome not very projecting, though defined from the anterior lip by a distinct sinus. Posterior lip membranous, each lobe having at the end exteriorly a small denticle. Mandibles rather strong, molar expansion short and thick, nearly transversely truncated’ at the tip, palp scarcely longer than the mandible and originating at about the same level as the latter. Maxillee nearly as in Alibrotus. Maxillipeds less strong, masticatory lobe reaching to the end of the antepenultimate joint of the palp, the latter not nearly so robust as in the said genus and attenuated distally. Anterior gnathopoda of moderate size, distinctly subcheliform. Post- erior gnathopoda about as in Alibrotus. Pereiopoda rather short and robust, the 3 posterior pairs sometimes very stout, with the joints laminarly expanded. Last pair of uropoda very short, scarcely reaching beyond the preceding pair, rami without any marginal sete. Telson short and broad, more or less dis- tinctly incised posteriorly. Remarks. — In the restriction here adopted this genus is chiefly dis- tinguished from the preceding one by the much more robust form of the body, by the shorter and stouter antenne and legs, as also by the poor development of the last pair of uropoda. The genus would seem to be chiefly confined to the Arctic seas and contains several species, some of which are, however, as yet imperfectly known. Besides the 3 Norwegian forms described in the sequal, two new species, O. turgidus and O. leucopis were procured on the Norwegian North Atlantic Expedition, and Dr. Hansen has added 3 new species from the Kara Sea, viz., O. caricus, brevicaudatus and affinis. Finally Dr. Stuxberg enumerates 3 species from the Siberian Polar Sea, viz., O. zebra, vorax, and abyssicola, without however giving any description or figure, 46. Onesimus Edwardsii, (Kroyer). (Pl. 36, fig. 1.) Anonyx Edwardsii, Kroyer, Nat. Tidsskr. 2 Rekke, Bd. 2, p. 1. Body rather robust and tumid, with broadly vaulted back. Cephalon about the length of the 1st segment of mesosome, lateral corners but slightly projecting and evenly rounded at the tip. First pair of coxal plates rather expanded below; the 2 succeeding ones scarcely twice as deep as the corres- ponding segments; 4th pair somewhat broader, with the posterior expansion short and obtusely truncated; 5th pair nearly as deep as broad. Last pair of epimeral plates of metasome produced at the lateral corners to a narrow slightly upturned lobe. First segment of urosome deeply depressed dorsally. Eyes rather large, oblong oval, slightly expanding below, pigment bright red. Superior antenne in female about the length of the cephalon and the 2 first segments of mesosome combined, 1st joint of the peduncle very large and tumid; flagellum somewhat longer than the peduncle and composed of about 15 articulations, the 1st of which does not exceed the 2 succeeding ones com- bined; accessory appendage nearly half the length of the flagellum and 6-ar- ticulate. Inferior antenne a little longer than the superior, flagellum com- posed of about 18 articulations. Anterior gnathopoda with the propodos much longer than the carpus, slightly curved in its outer part, and nearly trans- versely truncated at the tip, palmar edge somewhat arcuate and finely den- ticulated. Posterior gnathopoda very slender, propodos exceeding half the length of the carpus and slightly dilated distally. Posterior pereiopoda rather stout, meral joint somewhat thickened; basal joint of last pair oval, equalling in length the remainder part of the leg. Last pair of uropoda with the inner ramus about as long as the basal joint of the outer, and armed on the inner edge with 2 small denticles. Telson rounded, scarcely more long than broad, posterior incision very short, terminal lobes obtusely rounded, each . with a very smal denticle. Colour pale reddish yellow; ova in the marsupial pouch bright orange. Length of adult female 11 mm. Remarks. — The present species may be regarded as the type of the genus. It is easily known from the 2 succeeding species by the obtusely rounded lateral corners of the cephalon, as also by the structure of the an- terior gnathopoda, and partly also by the form of the posterior pereiopoda. Occurrence. —I have myself never met with this form out of the Are- tic region. According to Boeck, however, it is said to occur rarely at Lyng- holmen in the outer part of the Hardangerfjord, and Bruzelius likewise re- cords the species from the West coast of Norway. In Finmark I have found it not unfrequently at depths varying from 20 to 50 fathoms. Distribution. — Arctic Ocean widley distributed: Greenland, Spits- bergen, Iceland, Jan Mayen, Franz Josephs Land, the Murman coast, the Kara Sea, the Siberian Polar Sea, Arctic North America; Bohuslin (Bruze- lius), Kattegat (Meinert). 47. Onesimus Normani, Schneider, M. 8. (Pl. 36, fig. 2). Body short and stout, though somewhat more compressed than in the preceding species. Cephalon scarcely as long as the Ist segment of mesosome, lateral corners somewhat produced and acute at the tip. First pair of coxal plates scarcely widening below; the 2 succeeding ones nearly twice as deep as the corresponding segments; 4th pair but slightly emarginated posteriorly and forming below the emargination a rather short and blunt projection; 5th pair about as deep as broad. First pair of epimeral plates of metasome pro- duced at the infero-anterior corners to a narrow hook-like projection; last pair with the infero-posterior corners drawn out to a sharp upturned point. First segment of urosome scarcely impressed dorsally. Eyes oblong oval, somewhat narrower than in the preceding species, pigment red. Both pairs of antenne in female very short and stout, nearly subequal in length: superior ones with the peduncle much tumeficated, flagellum but very little longer than the peduncle and composed of 8 articulations only, the Ist of which is very large, about equalling in length the whole remainder part of the flagellum; acces- sory appendage exceeding half the length of the flagellum and 3-articulate, Ist joint twice the length of the other 2 combined. Inferior antennee with the flagellum shorter than the peduncle and only composed of 8 articulations. Anterior gnathopoda with the propodos scarcely longer than the carpus, pal- mar edge straight, densely spinulose and very oblique, inferior angle obsolete. Posterior gnathopoda with the propodos half the length of the carpus and scarcely widening distally. Posterior pereiopoda somewhat less robust than in the preceding species; but otherwise rather similar. Last pair of uropoda with the inner ramus simple lanceolate, without any marginal denticles; pe- nultimate pair with the imner ramus deeply indented beyond the middle, terminal part spinitorm. Telson a little more long than broad, posterior incision deeper than in O. Edwardsii, terminal lobes slightly indented at the tip. Colour not stated. Length of female 9 mm. = Remarks. — The present new species was first detected by Mr. Schnei- der in the neighbourhood of Tromsé, Finmarken, and has been named by that author in honour of the well known British naturalist, the Rev. A. Norman, who last summer was accompanied by Mr. Schneider during his 107 investigations of the fauna of the Varangerfjord. I have had an opportunity of seeing his detail drawings of the species and have thereby been enabled to indentify his species with a formrecently found by me in one solitary specimen among my material of O. Edwardsii. The species is easily distinguished from the latter by the form of the lateral corners of the cephalon, by the very short and stout antenne and by the structure of the anterior gna- thopoda. Occurrence. — As stated above, Mr. Schneider found this species in the neighbourhood of Tromsé, and the specimen here figured was probably likewise from some place in Finmark. 48. Onesimus plautus, (Kriyer). (Pl. 37, fig. 1-) Anonyx plautus, Kroyer, Nat. Tidsskr, 2. Reekke, Bd. 1, p. 629. Body short and robust, though somewhat compressed. Cephalon lon- ger than the Ist segment of mesosome, lateral corners acute at the tip. An- terior coxal plates rather narrow and about twice as deep as the body; Ist pair scarcely expanded below; 4th pair but very little emarginated posteriorly and obtusely produced below the emargination; 5th pair rather large, fully as deep as broad. Last pair of epimeral plates of metasome considerably produced at the lateral corners and terminating with an upturned point. First segment of urosome but very slightly impressed dorsally. Eyes irre- gularly oval and considerably expanded below, in male much larger than in female, pigment red. Superior antenne in female about the length of the cephalon and the 2 first segments of mesosome combined; peduncle rather thick; flagellum attenuated, somewhat longer than the peduncle and composed of about 11 articulations, the Ist of which about equals in length the 3 succeeding ones combined; accessory appendage a little exceeding the half length of the flagellum and 4-articulate, Ist joimt longer than the others combined. Inferior antennee somewhat longer than the superior, flagellum composed of about 13 articulations. Both pairs of antenne in male conside- rably longer than in female, the flagella being very slender and composed of a greater number of articulations. Anterior gnathopoda with the propodos about the length of the carpus and nearly transversely truncated at the tip, though the inferior corner is rounded off. Posterior gnathopoda with the propodos exceeding half the length of the carpus and slightly dilated distally. Posterior periopoda very short and strongly built, meral joint in all conside- rably expanded, basal jot of last pair oblong oval and much longer than 108 the remainder part of the leg. Last pair of uropoda with both rami quite naked, the inner the shorter. ‘Telson rounded oval, a little more long than broad, posterior incision narrow and not nearly extending to the middle, ter- minal lobes indented at the tip. Colour (according to Kréyer) reddish yellow, the back being somewhat darker. Length of adult female 8 mm. Remarks. — This species, first described by Kroyer, is at once distinguished from any of the 2 preceding ones by the peculiar robust form of the 3 posterior pairs of pereiopoda, in which respect it shows a perplexing resemblance to another rather different Lysianassid, viz., Menigrates obtusifrons (Boeck) to be described in the sequel. This apparent resemblance has indeed caused the two forms to be often confounded with each other, as will be shown farther on. Occurrence. — I have not myself met with this species, but a few specimens are preserved in our University Museum, collected by Boeck off the West coast of Norway at Haugesund. Distribution. — Arctic Ocean: Greenland, Spitsbergen, the Murman Coast, the Kara Sea, the Siberian Polar Sea (Stuxberg); Bohuslin (Stock- holm Museum). Gen. 27. Chironesimus, G. 0. Sars, n. Syn: Anonyx, Hoek (ex parte). Body thickish, with comparatively large coxal plates; the last pair of epimeral plates of metasome produced atthe lateral corners. Antenne (in female) about as in Onesimus, the inferior ones being a little longer than the superior. Epistome not at all projecting. Anterior lip forming in front a rather large and compressed linguiform lobe. Mandibles of moderate size, cutting edge with a secondary tooth on the inner corner, molar expansion tapering to a blunt ciliated point, palp rather large and originating somewhat nearer the tip than does the latter. First pair of maxilla with the mas- ticatory lobe large and obliquely truncated, terminal spines rather strong and denticulated, basal lobe comparatively small and bisetose, palp normal. Second pair of maxille with the lobes rather short, the outer the larger. Maxilli- peds with the masticatory lobe broadly oval and scarcely reaching to the end of the antepenultimate joint of the palp; the latter of usual structure. Anterior gnathopoda comparatively short and distinctly subcheliform. Posterior gnathopoda elongated and rather powerful, propodos greatly expanded, with 109 a well defined concaved palmar edge, dactylus strong and curved. Pereiopoda comparatively slender, basal joint of the 3 posterior pairs large and laminar. Branchial lamella simple. Last pair of uropoda much larger than in Onesi- mus and reaching considerably beyond the preceding pair, both rami partly setous on the inner edge. Telson oblong and deeply cleft. Remarks. — The present new genus is intermediate in character be- tween the genera Onesimus and Anonyx, resembling the former in the general form of the body, the latter in the structure of the oral parts and caudal appendages. From both it is markedly distinguished by the peculiar power- ful structure of the posterior gnathopoda, a character which has given rise to the generic title here proposed. It may be observed that two of the species described by Dr. Hansen from the Kara Sea and referred by him to the genus Onesimus exhibit a quite sintilar structure of these limbs, a fact which would seem to indicate a closer relation to the present genus. 49. Chironesimus Debruynii, (Hoek). (Pl. 37, fig. 2). Anonyx Debruynii, Hoek, Die Crustaceen gesammelt wihrend der Fahrten der »Willem Ba. rents». Niederl. Arch. fiir Zoologi. Suppl. Bd. 1, p. 44, Pl. II, fig. 30. Body rather robust and tumid, with broadly rounded back. Cephalon about the length of the 1st segment of mesosome, lateral corners somewhat produced and narrowly rounded at the tip. Anterior coxal plates fully twice as deep as the body; 1st pair scarcely expanded below; 4th pair deeply emargt- nated posteriorly and forming below the emargination a rather large angular expansion; 5th pair not very large, more broad than deep. Last pair of epl- meral plates of metasome produced at the lateral corners to an acute trian- gular, somewhat upturned lobe. First segment of urosome but slightly de- pressed dorsally. Eyes oblong oval, a little broader below, pigment red. Superior antennz about the length of the cephalon and the 2 first segments of mesosome combined; 1st joint of the peduncle very large and thick; flagel- lum exceeding the peduncle by about 1/1 of its length and composed of about 11 articulations, the Ist of which equals in length the 3 succeeding ones combined; accessory appendage about half the length of the flagellum and 6-articulate, 1st joint being very large and somewhat expanded. Interior antenne a little longer than the superior, the 2 outer peduncular joints nearly of uniform length, flagellum composed of about 15 articulations. Anterior gna- thopoda with the propodos scarcely as long as the carpus and much narrower, palmar edge slightly concaved and detined below almost rectangularly. 15 — Crustacea. Posterior gnathopoda with the propodos very large, gradually expanded di- stally, palmar edge defined below by a projecting angle and coarsely denti- culated in its outer part, dactylus much curved and likewise denticulated on the coneaved edge. Basal joint of the last pair of pereiopoda regularly oval in form and about as long as the remainder part of the leg. Last pair of uropoda with the rami nearly equal in length and broadly lanceolate. Telson nearly twice as long as broad and without any trace of dorsal denticles, cleft extending beyond the middle and gradually widening in its outer part, terminal lobes blunt, each with a small apical denticle. Co- lour not stated. Length of adult female 14 mm. Remarks. — There cannot, I think, be any doubt that the form de- seribed by Hoek as Anonyx Debruynii is identical with the present form, although the number of articulations in the antennal flagella is much greater; but this may perhaps be accounted for by the specimen of Hoek being a young male. It is now for the first time added to the Norwegian fauna. Occurrence. — I have as yet only met with 3 specimens of this form, one of which was found at Christiansund on the West coast of Norway, the two off the Lofoten isles; depth 50 —100 fathoms. Distribution. — The Barents Sea (Hoek). 6 (5 Gen. 27, Menigrates, Boeck, 1870. Body of unusually coarse structure, with rather large coxal plates and the last pair of epimeral plates of metasome produced at the lateral corners. Antenne in both sexes short and stout, those of the male provided with very distinct calceole. Epistome flattened in front and not distinctly defined from the anterior lip, both together forming a rather narrow flap- shaped projection. Posterior lip with the lobes narrowly rounded at the tip. Mandibles rather elongated, cutting edge simple, molar expansion very slight, palp of moderate size and originating much nearer the base than does the latter. First pair of maxillee nearly as in Onesimus; second pair with the inner lobe somewhat more elongate, though a little shorter than the outer. Maxillipeds with the masticatory lobe rather large, reaching considerably beyond the antepenultimate joint of the palp, the latter not very large. An- terior gnathopoda not subcheliform, the propodos wanting any distinetly de- fined palmar edge. Posterior gnathopoda very slender, propodos not at all produced beneath the minute dactylus. Pereiopoda very strong and stout, 111 especially the 3 posterior pairs, the joints of which are in parts much expanded. Last pair of uropoda extremely small, with the rami quite naked. Telson short and broad, rounded, slightly incised posteriorly. Ttemarks. — The present genus has been established by Boeck in order to include a form which, though resembling the species of Onesimus in its outer habitus, yet exhibits considerable difference in certain characters of apparently generic value, thus in the structure of the oral parts and in that of the anterior gnathopoda. It contains as yet but a single species. 50. Menigrates obtusifrons, Boeck. (Pl. 38, fig. 1.) Anonyx obtusifrons, Boeck. Forhandl. ved de Skand. Naturf. 8Sde Mode 1860, p. 643. Syn: Anonyx brachycercus, Lilljeborg. > Anonyx plautus, Sp. Bate (not Kroyer). Body very robust and much tumeficated, with broadly vaulted back. Cephalon shorter than the Ist segment of mesosome, lateral corners somewhat produced and angular at the tip. Anterior coxal plates nearly twice as deep as the body and successively increasing in size posteriorly; 4th pair but slightly expanded in their lower part; 5th pair rather large, about as deep as broad, and produced at the infero-posterior corners to a short deflexed lobe. Last pair of epimeral plates of metasome drawn out at the lateral corners to a short triangular upturned projection. First segment of urosome scarcely impressed dorsally. Eyes of moderate size, oval or reniform, pigment red. Superior antenne in female scarcely longer than the cephalon and the Ist segment of mesosome combined; peduncle much tumeficated, with the 2 outer joints very short; flagellum but little longer than the peduncle and composed of 8 articulations only, the Ist of which equals in length the 3 succeeding ones combined; accessory appendage exceeding half the length of the flagellum and 4-articulate, Ist joint by far the largest. Inferior antenne in female scarcely longer than the superior, flagellum 8-articulate; immale a little more elongated, with the flagellum, like that of the superior, composed of a greater number of articulations. Anterior gnathopoda rather powerful; propodos nearly twice the length of the carpus, somewhat curved and gradually taper- ing distally, dactylus strong and curved. Posterior gnathopoda with the propodos about half the length of the carpus, oblong oval, scarcely dilated distally. Posterior pereiopoda yery short and robust, of much the same appearance as in Onesimus plautus, the meral joint being considerably ex- panded and the basal joint, especially of the last pair, very large. Last pair of uropoda scarcely reaching to the end of the preceding pair, inner ramus simple lanceolate and a little shorter than the outer. Telson about as broad 112 as long, posterior incision narrow and not extending to the middle, terminal lobes obtusely truncated at the tip, each with a small apical denticle. Co- lour pale yellowish with a faint reddish tinge on the anterior division of the body. Length of adult female 13 mm. Remarks. — Owing to a certain resemblance in its outer habitus and especially in the structure of the posterior pereiopoda to Onesimus plautus (Kroyer) this form was confounded with the latter by Sp. Bate, and even Boeck, in determining the specimens of both forms preserved in our University Museum, has fallen into considerable error, some of the specimens having been labelled by him as Onesimus plautus, whereas specimens of the latter form were vice- versa determined as Menigrates obtusifrons. On a closer examination the present form may, however, easily be destinguished from Onesimus plautus, not only by its much more tumid body, but also by the considerably coarser structure of the antennze and by the very different form of the anterior gna- thopoda. Occurrence. — 1 have myself only met with this form in 2 localities within the Arctic region of Norway, viz., at Bodé and in Lofoten at depths varying from 20 to 50 fathoms. Prof. Lilljeborg found it, however, at Grip outside Christiansund on the West coast of Norway, and Boeck has stated its occurrence also off the South coast at Mandal. Finally, Mr. Schneider has observed it inthe neighbourhood of Tromsé. None of these authors, however, would seem to have observed this form in its fully adult state. Distribution. — British Isles (Sp. Bate). Gen. 29. Lepidepecreum, Sp. Bate, 1868. Body short and stout, with the back carinated and the integuments very firm, caleareous. Coxal plates large and deep. Superior antenne with the joints of the peduncle partly produced anteriorly, accessory appendage very small or quite wanting; in male without any caleeole but provided with dense tufts of sensitive bristles. Inferior antenne in female scarcely as long as the superior and much more slender, with the antepenultimate peduncular joint rather produced; in male very elongate, exceeding the length of the body, flagellum very slender, filiform and provided with distinct cal- ceole. Epistome forming a broad compressed plate projecting in front of the anterior lip. Mandibles of moderate size, cutting edge simple, molar expan- sion very slight, palp extremely slender and originating close to the base of the mandible. First pair of maxille with the masticatory lobe not very strong and nearly transversely truncated at the tip, basal lobe attenuated, bisetose, palp normal. Second pair of maxille with the lobes moderately elongate, the inner somewhat shorter and much narrower than the outer. Maxillepeds comparatively small, masticatory lobe oblong oval and reaching beyond the antepenultimate joint of the palp, the latter poorly developed. Anterior enathopoda rather slender, subcheliform, propodos narrow, with the palmar edge concaved and defined below by a projecting angle armed with 2 slender spines, dactylus with a secondary denticle near the tip. Posterior gnathopoda likewise very slender and only very sparingly setous, propodos produced be- neath the dactylus to a digitiform projection so as to form a complete chela. Anterior pereiopoda slender and feeble in structure, posterior ones with the basal joint laminarly expanded. Last pair of uropoda in female scarcely reaching beyond the preceding pair, rami hardly setous; in male much larger, both rami provided on the inner edge with plumous sete. Telson conically attenuated and deeply cleft. Remarks. —- The present genus, established by Sp. Bate, is chiefly characterised by the compact, dorsally carmated body, the peculiar structure of the superior antenne, as also of both pairs of gnathopoda, and by the form of the telson. Besides the 2 northern species described in the sequel, a third species, L. foraminiferum (Stebbing), has been added from the Challenger Expedition. 51. Lepidepecreum carinatum, Sp. Bate. (RIS 38; fee 2)) Pl 39) fie 1.) Lepidepecreum carinatum, Sp. Bate & Westwood, British Sessile-eyed Crustacea, Vol. 2, Appendix, p. 509. Syn: Anonyx longicornis, Sp. Bate (male). >» lLepidepecreum mirabile, Meinert. (female). Body in female rather short and greatly compressed, dorsal carina distinct along the whole mesosome and metasome, as also on the Ist segment of urosome, forming on the latter and on the last segment of metasome a large and compressed conico-acuminated projection. A lateral carina also is present extending across the upper part of the coxal plates. Body of male considerably more slender, with the metasome comparatively larger and the 2 posterior dorsal projections somewhat smaller and less regular in form. Cephalon in both sexes considerably longer than the Ist segment of meso- some, somewhat constricted on the middle and forming between the superior antenne a small rostriform projection, lateral corners drawn out to large somewhat deflexed linguiform lobes. Anterior coxal plates rather large, in female fully twice as deep as the body, in male somewhat less deep; 4th pair in female considerably expanded in their inferior part and angularly produced below the deep posterior emargination; 5th pair quadrangular, about as deep as broad, with the posterior edge slightly concaved. Last pair of epimeral plates of metasome not at all produced at the lateral corners. Eyes oval, somewhat larger in male, pigment reddish with an opaque white coat- ing. Superior antenne in female scarcely longer than the cephalon and the Ist segment of mesosome combined; Ist joint of the peduncle very large, com- pressed, carinated dorsally and jutting out at the end anteriorly as an ob- tusely acuminated projection advancing over the succeeding joint, which forms a similar but much smaller projection; flagellum much shorter than the peduncle and composed of but 7 articulations, the Ist of which equals in length the 2 succeeding ones combined; accessory appendage quite wanting. Same antenne in male a little larger than in female, with the 2nd peduncu- lar joint scarcely produced anteriorly, flagellum 9-articulate, with the Ist joint very large and densely clothed with sensitive bristles. Inferior antenne in female considerably shorter than the superior, penultimate joint of the peduncle much larger than the ultimate one and slightly produced at the end anteriorly, flagellum very short and 4+articulate. KEpistomal plate very large, nearly rectangular. Anterior gnathopoda with the basal jomt about the length of the remainder part of the leg, propodo& shorter than the carpus and not at all expanded distally. Posterior gnathopoda extremely slender; propodos exceeding the half length of the carpus, oblong triangular, with two transverse rows of strong sete near the base of the dactylus. Posterior pereiopoda rather robust, basal joint of the 3rd pair rounded, that of the 2 succeeding ones irregularly oval, constricted near the end; meral joint in all rather expanded and finely ciliated on the posterior edge. Last pair of uro- poda in female with the rami nearly linear in form, the outer somewhat longer than the inner and without any trace of marginal bristles; those of male lanceolate and considerably expanded at the base. Telson exceedingly narrow and elongate, nearly 3 times as long as broad at the base, gradually tapering to the conical tip; cleft very narrow, fissure-like, and extending far beyond the middle. Colour a chalky white, each segment haying dorsally a small orange-coloured patch, more expanded in male. Length of female 7 mm., of male 8 mm. Remarks. — This is ‘a very pretty and easily recognizable form, though one which shows considerable differences in the two sexes, a fact that indeed has led Sp. Bate to describe the species under two different names, 115 as Anonyx longicornis and as Lepidepecrewm carninatum, the former being the adult male, the latter the female. I think the first named specific appellation must be cancelled as only referring to a masculine character, although it is of somewhat older date than the name subsequently assigned to the female. The form recently described by Prof. Meinert as Lepidepecrewm mirabile 1 am unable to distinguish from the present species. The lateral carina, it is true, has not been observed by Sp. Bate; but this carina may easily be overlooked when the animal is only viewed from a lateral standpoint. Occurrence. — Off the coast of Norway this species would seem to be confined to the most southern part. I have found it rather sparingly at Lushavyn, situated at the eastern corner of Lister, and at Meerdé, outside Aren- dal, at depths varying from 10 to 30 fathoms, in sandy bottom. Distribution. — British Isles (Sp. Bate), Denmark (Meinert); Mediter- ranean (found by the author at Spezia). 52. Lepidepecreum umbo, (Goés). (Pl. 39, fig. 2.) Lysianassa umbo, Goés, Crust. amphip. maris Spetsbergize, p. 4, fig. 6. Body very robust and compact in both sexes, with the back consi- derably curved; dorsal carina increasing in height posteriorly, the segments being partly produced dorsally at the end; last segment of metasome and Ist of urosome jutting out dorsally as an acute somewhat upturned projection Cephalon about the length of the Ist segment of mesosome, lateral corners considerably produced and acute at the tip. Coxal plates very large and deep, the 4 anterior ones being nearly 3 times as deep as the body; 4th pair rather narrow in their upper part, but considerably expanded below, forming an obtuse linguiform lobe beneath the rather deep emargination; 5th pair unusually large, oval, much more deep than broad, with the infero-posterior corners produced downwards, and exhibiting in the centre a most conspicuous umboniform eminence; 6th pair also rather deep and obliquely truncated at the infero-posterior corners. Last pair of epimeral plates of metasome nearly rectangular, very slightly produced at the lateral corners. Eyes narrow oblong, pigment red. Superior antenne about twice the length of the cepha- lon; Ist joint of the peduncle produced at the end in a similar manner as in the preceding species, the other 2 not produced; flagellum in female shorter than the peduncle and composed of 8 articulations, the Ist of which equals in length the 4 succeeding ones combined; accessory appendage distinct, but extremely small, and triarticulate. Inferior antenne in female nearly as long as the superior, but much more slender, flagellum 8-articulate. An- 116 tenne in male modified in a quite similar manner as in the preceding species. Epistomal plate not quite so large as in that species and obtusely rounded in front. Anterior gnathopoda with the basal jomt considerably longer than _ the remainder part of the leg, propodos about the length of the carpus and slightly dilated distally. Posterior gnathopoda less slender, carpus consider- ably expanded in its outer part, propodos ‘somewhat stronger than in the preceding species and provided dorsally with 3 rows of sete. Posterior per- eiopoda rather feeble in structure, 3rd pair very small, with the basal joint nearly elliptical and more broad than long, that of the last pair very much expanded and broadly oval in form; meral joint in none of the legs expanded. Last pair of uropoda in female with the rami somewhat broader than in the preceding species, the inner one scarcely longer than the basal joint of the outer, the latter with 2 bristles on the inner edge. Telson oblong triangular, scarcely twice as long as broad at the base; cleft narrow and extending far beyond the middle. Colour bright carneous red. Length of adult female 11 mm. Remarks. — This form, which was erroneously referred by Boeck to his genus Orchomene, is evidently congeneric with the preceding species, agreeing as it does pretty well in all essential points. Yet it is very easily recognized from that species by several well marked characters, viz., by the unusually high and compact body, the very conspicuous lateral umboniform prominence, the much feebler structure of the posterior pereiopoda, and finally by the colour of the body. Occurrence. — Unlike the preceding species, this is evidently a genuine northern form, rarely occurring out of the Arctic region. I have found it in several places both off the coast of Finmark and off the Lofoten isles in depths varying from 30 to 100 fathoms. The southernmost place where I have met with it is at Brénésund in Nordland. Distribution. — Arctic Ocean: Spitsbergen (Goés), the White’ Sea (Jarzynsky), Stat. 48 and 124 of the Norwegian North Atlantic Expedition. Gen. 30. Huonyx, Norman, 1866. Body robust, with rather firm integuments and large coxal plates. Superior antenns of moderate size and provided with a well developed acces- sory appendage. Inferior antenne in female much longer than the superior. 117 Epistome not at all projecting. Anterior lip produced in front to an acutely triangular deflexed lobe. Mandibles comparatively small, cutting edge simple, obtuse; molar expansion obsolete, palp very large and originating nearer the tip than the base of the mandible. First pair of maxille withthe masticatory lobe rather large and obliquely truncated, terminal spines unusually small, claw-like; basal lobe rounded oval, with several apical bristles, palp normal. Second pair of maxille with both lobes short and obliquely truncated at the tip. Maxillipeds with the masticatory lobe very small, scarcely larger than the basal lobe, and provided with slender sete on the edge; palp rather robust. Anterior gnathopoda slender and elongate, sparingly setous, propodos forming together with the dactylus a perfect chela. Posterior gnathopoda stronger than usual, propodos dilated distally, subcheliform; dactylus large and curved. Pereiopoda powerfully developed. Last pair of uropoda reaching beyond the preceding pair, rami lanceolate. Telson oblong, deeply cleft. Remarks. — This genus established by the Rey. Mr. Norman, is pro- minently distinguished from oll other Lysianasside by the peculiar chelate character of the anterior gnathopoda, as also by the powerful structure of the propodos of the posterior ones. Moreover the oral parts exhibit in their structure several peculiarities, which would seem to point to a semiparasitic habit. Besides the species described in the sequel, the Opis leptochela of Sp. Bate undoubtedly belongs to the same genus, and the Rev. Mr. Stebbing has described another species, E. Normani, from the Challenger Expedition. 53. Euonyx chelatus, Norman. (Pl. 40, fig. 1). Euonyx chelatus, Norman, Report of the British Association for the Advancement of Science f. 1866, p. 202. Body rather strong and thickset, with broadly rounded back. Cepha- lon somewhat longer than the 1st segment of mesosome, forming anteriorly between the bases of the superior antenne a blunt curved rostral projection, lateral corners but slightly produced and nearly rectangular. First pair of coxal plates extremely small and rudimentary; the 3 succeeding pairs very large, fully 3 times as deep as the body; the 4th considerably expanded below and jutting out posteriorly as an acute lobe; 5th pair likewise rather large, fully as deep as broad. Last pair of epimeral plates of metasome pro- duced at the lateral corners to a short and blunt point. First segment of urosome deeply impressed at the base dorsally and exhibiting behind the depression a high and compressed hump-like projection. Eyes oblong oval and somewhat constricted at the middle, pigment chalky white. Superior antenne 15b — Crustacea. 115 about the length of the cephalon and the 2 first segments of mesosome com- bined, 1st joint of the peduncle very large and broad, concaved at the super- ior (dorsal) edge and jutting out at the end anteriorly as a blunt projection; flagellum nearly twice the length of the peduncle and composed of about 10 articulations, the Ist of which is very large, about equalling in length the 4 succeeding ones combined; accessory appendage not quite half the length of the flagellum and 5-articulate. Inferior antenne nearly twice the length of the superior, flagellum very slender and composed of about 22 articulations. Anterior gnathopoda extremely slender and nearly naked, propodos scarcely longer than the carpus and rather narrow, chela occupying the outer third part of the propodos. Posterior gnathopoda somewhat longer and much stronger than the anterior, propodos about half the length of the carpus, gra- dually expanded distally aud densely setous at the tip, palmar edge concaved and defined by a projecting angle, dactylus rather strong and curved. Perei- opoda of very powerful structure and edged with fascicles of short spines; carpal joint in all very short, and dactylus strong and curved; basal joint of the 3 posterior pairs not very large, rounded; meral joint considerably ex- panded. Last pair of uropoda with the rami naked, the inner one scarcely longer than the basal joint of the outer. Telson likewise unarmed, oblong in form, nearly twice as long as broad; cleft narrow, extending far beyond the middle, terminal lobes blunt at the tip. Colour whitish, with a faint yellowish tinge. Length of adult female 10 mm. Remarks. — The description given by the Rey. Mr. Norman of, his Euonyx chelatus agrees pretty well with the present form, so that there cannot be any doubt about the identity of both. As to Opis leptochela of Sp. Bate, this form, on the other hand, though evidently congeneric, would seem to differ in several characters, thus in the shape of the cephalon and of the coxal plates and in the small size and rounded form ofthe eyes. Only female specimens have as yet occurred to me. It is now for the first time, added to the Norwegian fauna. Occurrence. — 1 have found this remarkable form in two widely di- stant localities, viz., at Vardé, Finmark, where a single specimen was pro- cured from a depth of 50—60 fathoms, and in the Trondhjemsfjord. In the latter locality it occurred at Leksvigen and Vennes rather sparingly in the region of the deep sea corals at a depth of 100 to 150 fathoms. It was also last summer procured by Mr. Storm in the outer part of the fjord, at about the same depth. Mr. Norman found his specimen parasitic on Kchinus escu- lentus, and the same was also stated by Sp. Bate to have been the case with a specimen of Opis leptochela taken by Mr. Brady off the Isle of Man, Distribution. — British Isles, Hebrides (Norman). 119 Gen. 31. Kerguelenia, Stebbing, 1888. Body extremely short and compact, with the coxal plates very large and deep, especially those of the 4th pair. Antenne in both sexes short, the in- ferior much more slender than the superior, the latter only modified in the male. Oral parts poorly developed. Epistome not projecting. Mandibles blunted at the tip, without any distinct cutting edge or molar expansion, palp slender originating at the tip of the mandible. Maxillee extremely small, though composed of the usual parts. Maxillipeds with the masticatory and basal lobes rudimentary, palp elongate, with the dactylus styliform. Both pairs of gnathopoda slender and elongate, the anterior nearly naked and terminating with a pointed extremity, the dactylus extending in the same line as the propodos, upon which it is scarcely movable; the posterior ones finely hairy in their outer part, propodos produced beneath the extremely small dactylus so as to form a very minute chela. Anterior pereiopoda slender posterior ones short and robust, with the meral joint considerably expanded, basal joint of 3rd pair nearly linear, that of the 2 last pairs large and lami- nar. Last pair of uropoda extremely small, with rudimentary rami. Tel- son likewise very small, rounded, entire. Remarks. — As to the general habitus of the body, this genus, recently established by the Rey. Mr. Stebbing, somewhat recalls the genus