f Digitized by the Internet Archive in 2007 with funding from IVIicrosoft Corporation http://www.archive.org/details/accountofcrustac67sarsrich AN ACCOUNT OF THE CRUSTACEA OF NORWAY AN ACCOUNT OF THE CRUSTACEA OF NORWAY WITH SHORT DESCRIPTIONS AND FIGURES OF ALL THE SPECIES BY G. O. SARS PROFESSOR OF ZOOLOGY AT THE UNIVERSITY OF CHRISTIANIA VOL. VI COPEPODA CYCLOPOIDA WITH 118 AUTOTYPIC PLATES BERGEN PUBLISHED BY THE BERGEN MUSEUM SOLD BY ALB. CAMMERMEYERS FORLAG, CHRISTIANIA 1918 LIBRARY UNIVERSITY OF PAi iFr»DMii BERGEN. A/S JOHN GRIEGS BOKTRYKKERl PREFACE. In concluding this Volume, I wish to observe that I am far from claiming it to give any exhaustive account of the group treated off. Especially as regards the semiparasitic forms belonging to the sections Slphonostoma and Poecilostoma, there is certainly still much to do, and I have no doubt that, on a closer and more methodical investigation of these interesting forms, many new species will be added to those here described, the greater number of which have been met with only quite accidentally in isolated specimens detached from their hosts. Yet I hope that this Volume will be useful as comprehending what is as yet known about this part of our Fauna. As to the plates accompanying the present Volume, they are, as will be seen, reproduced in quite a different manner from those in the preceding Volumes, where the autographic method has been applied throughout. This latter method may indeed give very good results, as seen from some of the earlier Volumes of the present work. But the method involves some danger for the clearness of the drawings, if not the outmost care is taken in their transfer on the stone. I have been very sorry to see that several of the plates accompanying the last (5th) Volume, for want of an habile and experienced printer, have been less satisfactorily reproduced, and I therefore have thought it right to abandon this method altogether and to chose another method, the phototypic one, which, though somewhat more costy, will better ensure the perfect reproduction of my drawings. By the elaboration of the present Volume I have been assisted by the same gentleman who did it in the case of the preceding Volume, and my hearty thanks are here again paid to them for their kindness. I also is much indebted to Prof. Wir^n of the Upsala University and to Mr. G. P. Farran, Dublin, for kindly sending me specimens for examination. My best thanks are moreover due to Mr. A. Kjaer for kindly having given me an opportunity of VI examining the bottom-residue of some large collecting bottles for search of semiparasitic forms. Several interesting species of both siphonostomous and poecilostomous Cyclopoida have thereby been secured and submitted to a closer investigation. Finally I beg to thank the direction of the Bergen Museum for the readiness with which it has admitted the increased expenses by the altered reproduction of the plates, and for the interest it has shown in the continued publication of my work. G. O. Sars. PRINCIPAL WORKS ON CYCLOPOIDA. Aurivillius, C. W. S. Bidrag til Kannedomen om Krustaceer, som lefva hos Mollusker och Tunicater. Stokh. 1883. Baird, W. Natural History of British Entomostraca. 1850. Boeck, A. Tvende nye parasitiske Krebsdyr. Forh. Chr. Vid. Selsk. 1859. — Oversigt over de ved Norges Kyster iagttagne Copepoder hen- herende til Calanidernes, Cyclopidernes og Harpacticidernes Familier. Forh. Chr. Vid. Selsk. 1864. — Nye Slaegter og Arter af Saltvandscopepoder; ibid. 1870. Brady. G. S. Monograph of British Copepoda, Vol. III. 1880. — Report on the Copepoda of the Challenger Expedition. 1883, — Revision of the British species of Fresh-water Cyclopidae and Calanidae. Nat. Hist. Trans. Northumb. & Durham. Vol. XI. 1891. . — Several other papers inserted in various English Journals. Canu, E. Les Hersiliidae, famille nouvelle de Copepodes commensaux. Contrib. ^ I'etude de la Fauna marine de Wimereux. V. 1898. — Les Copepodes de Boulonais 1892. Claus, C. Die freilebenden Copepoden. 1862. — Die Copepoden-Fauna von Nizza. 1866. — Ueber neue oder wenig bekannte halbparasitische Copepoden. Arch. Zool. Inst. Wien. Vol. VIII. 1889. Dana. J. D. Crustacea of the United States Expl. Exped. 1855. Farran. G. P. Second Report on the Copepoda of the Irish Atlantic-Slope. Fisheries Ireland Sci. Invest. 1908. — On Copepoda of the genera Oithona and Paroithona. Proc. Zool. Soc. London. 1913. VIII Fischer, S. Giesbrechi, W. Her rick, C. L. Jurine, L. Koch, C. L. Kurz, W. Lande, A. Lilljeborg, W. Mailer, 0. F. Nordman, A. Norman, A. M. Philippi, A. Rehberg, H. Richard, J. Sars, G. O. Beitrage zur Kenntniss der in der Umgegend von St. Peters- burg sich findenden Cyclopiden. Bull. Soc. Imp. Moscou, Vol. XXIV & XXVI. 1851. Die freilebenden Copepoden der Kieler Fohrde. 1882. Fauna & Flora des Golfes von Neapel. Pelagische Copepoden. 1892. Asterocheriden. 1892. Die Httoralen Cyclopiden des Golfes von Neapel. Mitth. Zool. Stat. Neapel. 1900. Synopsis of the Entomostraca of Minnesota. 1895. Histoire des Monocles. 1820. Deutschlands Crustaceen, Myriapoden und Arachniden. 1835 —41. Eunicicola Clausi, ein neuer Anneliden — Parasit. Sitzb. Akad. d. Wiss. Wien. Bd. LXXV. 1877. Materialy do Fauny Scorupiakow Widlonogish, Copepoda. 1890. De Crustaceis ex ordinibus tribus in Scania occurrentibus. 1853. Synopsis specierum Cyclopis Sueciae. Kgl. Vet. Akad. Handl, Vol. 35. 1901. Entomostraca. 1785. Mikrographische Beitrage zur Naturgeschichte wirbelloser Thiere. 1832. & Scott, T. Notes on the Nat. Hist, of East Finmark. Ann. Mag. Nat. Hist. ser. 7. Vol. XI. 1903. Crustacea of Devon & Cornwall. 1906. Beobachtungen iiber die Copepoden des Mittelmeeres. Wiegm. Arch. 1843. Beitrag zur Kenntniss der freilebenden Siisswasser-Copepoden. Abh. Verein zu Bremen, Vol. VI. 1880. Liste des Cladoceres et des Copepodes d'eau douce observes en France. Bull. Soc. Zool. France. Vol. XII. 1887. Oversigt af de indenlandske Ferskvands-Copepoder. Forh. Vid. Selsk. Chr. 1862. On the Crustacean Fauna of Central Asia. Part III. Copepoda and Ostracoda. 1904. Zool. Results of the 3rd Tanganyika Expedition conducted by Dr. W. A. Cunnington. Copepoda. 1909. IX Sars, G. O. Liste systematique des Cyclopoides, Harpacticoides et Monstril- loides receuillis pendant les campagnes de S. A. S, le Prince Albert de Monaco, avec -descriptions et figures des especes nouveiles. Bull. Inst, ocfeanogr. No. 323. 1916. Sars, M. Beskrivelse af 4 nye parasitiske Copepoder. Forh. Vid. Selsk. Chr. 1862. Schmeil, O. Deutschlands freilebenden SQsswasser Copepoden. Vol.1. Cyc- lopidae. 1892. Scott, A. Descriptions and Notes on some new and rare Copepoda from Liverpool Bay. Rep. Lancashire Sea-Fisheries Laboratory. 1896. — Report on the Pearl Oyster Fisheries of the Gulf of Mannar. Copepoda. 1903. — Copepoda of the Siboga Expedition. 1909. Scott, T. Report on Entomostraca from the Gulf of Guinea. Trans. Lin. Soc. London. Vol. VI. 1894. — Several other papers inserted partly in Ann. Rep. of the Fishery Board for Scotland, partly in Ann. Mag. Nat. Hist. Thompson, I. C. Revised Report on the Copepoda of Liverpool Bay. Trans. Liverpool Biol. Soc. Vol. VII. 1893. Thorell, T. Bidrag til Kannedomen om Crustaceer som lefva i Arter af SI. Ascidia. Kgl. Vet. Akad. Handl. Vol. III. 1860. Uljanin, W. N. Crustacea in Exp. Turkest. ab A. Fedtschenko coll. 1875. SYSTEMATIC LIST OF THE SPECIES DESCRIBED IN THE PRESENT VOLUME. Gnathostoma. Oithonidae. Oithona, Baird. spinlrostris, Glaus. similis, Glaus. Paroithona, Faran. parvula, Farran. Cyclopinidae. Cyclopina, Glaus. gracilis, Glaus. longicornis, Boeck. Schneideri, Scott. elegans, Scott. euacantha, G. O. Sars. pygmcea, G. O. Sars. Cyclopinella, G. O. Sars. tumidula. G. O. Sars. Cyclopetta, G. O. Sars. difficilis, G. O. Sars. Pterinopsyllus, Brady. insignis, Brady. Cyclopidae. Cyclops, Muller. pictus, Koch. abyssorum. G. O. Sars. lacustris, G. O. Sars. scutifer, G. O. Sars. vicinus, Uljanin. insignis, Glaus. vulgaris, Koch. gigas, Glaus. capillatus, G. O. Sars. lucidulus, Koch. robustus, G. O. Sars. pulchellus, Koch. biseiosus, Rehberg. crassicaudis, G. O. Sars. langvidus, G. O. Sars. diaphanus, Fischer. abyssicola, Lilljeborg, var leans, G. O. Sars. bicolor, G. O. Sars. Mesocyclops, G. O. Sars. obsoletus, Koch. olthonoldes, G. O. Sars. crassus, Fischer. Dybowskyi, Lande. gracilis, Lilljeborg. Pachycyclops, G. O. Sars. signatus, Koch. bistriatus, Koch. annulicornis, Koch. Leptocyclops, G. O. Sars. agilis, Koch. speratus, Lilljeborg. XII Lilljeborgi, G. O. Sars. maauroides, Lilljeborg. mac rums, G. O. Sars. Platycyclops, G. O. Sars. phaleratus, Koch. affinis, G. O. Sars. fimbriatus, Fischer. Siphonostoma. Ascomyzontidae. Ascomyzon, Thorell. asterocheres, Boeck. Lilljeborgl, Thorell. Boecki, Brady. simulans, Scott. latum, Brady. parvum, Giesbrecht. Echinocheres, Glaus. vlolaceus, Glaus. Dermatomyzon, Glaus. nignpes, Brady. Rhynchomyzon, Giesbr. purpurocinctum, Scott. rubrovittatum, G. O. Sars. Collocheres, Ganu. gracilicauda, Brady. Mesocheres, Norm. & Scott. anglicus, Norm. & Scott. Leptomyzon, G. O. Sars. elegans, A. Scott. Scottocheres, Giesbrecht. elongatus, Scott. Scottomyzon, Giesbr. gibberum, Scott. Acontiophoridas. Acontiophorus, Brady. $cutatus, Brady. Myzopontiidae. Myzopontius, Giesbr. pungens, Giesbr. Neopontius, Scott. angularis, Scott. Dyspontiidae. Dyspontlus, Thorell. striatus, Thorell. Cryptopontius, Giesbr. brevifurcatus, Giesbr. Arctopontius, G. O. Sars. expansus, G. O. Sars. Bradypontius, Giesbr. magniceps, Brady. papillaius, Scott. major, G. O. Sars. caudatus, G. O. Sars. Cribropontius, Giesbrecht. Normani, Brady. Artotrogidae. Artotrogus, Boeck. orbicularis, Boeck. Cancerillidae. Parartotrogus, Scott. arcticus, Scott. Cancerilla, Dalyell. tubulata, Dalyell. Poecilostoma. Clausidiidae. Hemlcyclops, Boeck. putpureus, Boeck. Hippomolgus, G. O. Sars. furcifer, G. O. Sars, XIII Lichomolgidae. Lichomolgus, Thorell. albens, Thorell. marginatas, Thorell. forflcula, Thorell. furcillata, Thorell. Canul, G. O. Sars. Pouchetl, Canu. tenuifurcatus, G. O. Sars. agllis, Leydig. Macrocheiron, Brady. fucicolum, Brady. hirsutipes, Scott. Pseudanthessius, Glaus. gracilis, Glaus. liber, Brady. assimilis, G. O. Sars. Sauvagei, Ganu. dubius, G. O. Sars. Lichomolgella, G. O. Sars. pusilla, G. O. Sars. Modiolicola, Auriv. insignis, Auriv. Hermannella, Canu. valida, G. O. Sars. parva, Norm. & Scott. prehensilis, G. O. Sars. finmarchica, Scott. tenuicaudis, G. O. Sars. Pseudomolgus, G. O. Sars. leptostylis, G. O. Sars. dilatatus, G. O. Sars. Rhinomolgus, G. O. Sars. anomalus, G. O. Sars. Sabelliphilus, M. Sars. elongatas, M. Sars. Oncaeidae. Oncasa, Philippi. borealis, G. O. Sars. similis, G. O. Sars. minuta, Giesbr. CorycaeidaB. Corycaeus, Dana. anglicus, Lubb. ErgasilidaB. Ergasilus, Nordman. Sieboldi, Nordm. Clausiidas. Conchocheres, G. O. Sars. malleolatus, G. O. Sars. Eunicicolidae. Eunicicola, Kurz. Qlausi, Kurz. i INTRODUCTION. Under the head Cyclopoida I comprise a number of Copepoda, which on the whole may be said to be built upon the type of our common fresh-water fleas (Cyclops), though exhibiting many modifications, both as to their general ap- pearance and to their habits, the latter affecting chiefly the structure of the oral parts. The present group, or sub-order, exhibits some relations both to the Calanoida and to the Harimcticoida, and also shows a certain approach to some of the other sub-orders distinguished by the present author, especially to the Notodeljjhyoida and the Caligoida, though the Cyclopoid type may always be easily recognisable. Whereas the extensive group Harpacticoida by earlier authors has generally been comprised within a single family, the Harpacticidce, several families referable to the present sub-order were established very early, though their real connexion under a common type has not been recognised. According to the system proposed by Dr. Giesbrecht, the Cyclopoida, like the Harpacticoida, should be included in the 2nd of his 2 primary divisions, the so-called Podoplea. This very extensive and heterogeneous group has been divided by that author into 2 sections, IsoJcerandria and Ampharthrandria, according to the non-prehensile or prehensile character of the anterior antennae in the male, each section comprising several families, which have been enumerated in his recent work on the family Aster ocheridce, p. 57. I am, however, by no means prepared to adopt this classification, which appears to me quite artificial, like the primary grouping of the Copepoda into Oymnoplea and Podoplea. In the sense here adopted, the sub-order Cyclopoida comprises families referred by Dr. Giesbrecht partly to the IsoJcerandria and partly to the Ampharthrandria^ whereas other families included by that author in the latter section are wholly removed as types of distinct sub-orders. One of these, the Harpacticoida, has been treated of in the preceding volume, the 4 remaining sub-orders, Notodelphyoida, Monstril- loida, Caligoida and Lernwoida, being reserved for the succeeding volumes of the present work. As mentioned above, the habits of the Cyclopoida are much more varied than is the case with the Calanoida and Harpacticoida. Some of them, for instance the species of the genus Oithona, are true pelagic animals, constituting a chief part of the plankton in almost all regions of the Oceans. Several other forms, like the Harpacticoida, live near the shores among algse or on a muddy bottom at different depths, and a great number of forms lead a more or less pronounced parasitic existence, attacking different invertebrate animals, in some instances also fishes. In most cases, however, the parasitism may be said to be merely temporary, though there are also a few examples of a more permanent parasitism, for instance in the case of Ergasilus and Nicothoe. The different mode and degree of parasitism has a great influence on the structure of the oral parts, and indeed we have in this feature a good guide for an exact subdivision of this group of Copepoda. The parasitic forms exhibit, as regards the structure of the oral parts, 2 well-marked types, both again differing conspicuously from the non- parasitic forms. We may accordingly divide the Cyclopoida into 3 natural sec- tions, for which I propose to retain the well-known names: gnatliostoma, siphono- stoma and poecilostoma. These names were first proposed by Thorell, but were taken in a much wider sense, viz., to divide the entire order Copepoda. I here restrict them to the group of Copepoda which will be treated of in the present volume. As to the general characters distinguishing this group, the external appearance of the body, as a rule, looks rather different from that found in the typical Harpacticoida by the very sharp demarcation of the 2 chief divisions of the body, the anterior one being more or less tumefied, the posterior very narrow. So far the Cyclopoida more resemble the Calanoida than the Harpacticoida, though they are easily distinguished from them by the very moveable articulation between the last 2 trunk-segments, the posterior of which, as a rule, is very small and firmly connected with the genital segment, so that, at first sight, it has the appearance of belonging more properly to the posterior than to the anterior division of the body. The anterior antennae are, as a rule, more elongated than in the Har- pacticoida and are composed of a greater number of articulations. There are, however, also some instances of a more or less great reduction of these limbs, both in size and in the number of joints. The posterior antennae are generally simple, without any outer ramus or exopodite. Only in a few of the parasitic forms is there a shght rudiment of such a ramus. In several of the poecilostomous Cyclopoida these antennae are transformed into powerful prehensile organs. The oral parts, as mentioned above, are of very different structure in the 3 sections of Cyclopoida. The natatory legs are, as a rule, shorter and stouter than in the Har- pacticoida, with the basal part broad and flattened and the rami generally well developed and subequal in size. The 1st pair are smaller than the succeeding ones and never prehensile. In a few of the parasitic forms, for instance Cancerilla, a considerable reduction of the natatory legs is found to have taken place, at least in the female. The last pair of legs are always very small and simple in structure, being in most cases exactly alike, in the two sexes. The ova are carried in 2 ovisacs, which are lateral or even subdorsal, never, as in the Harpacticoida, ventral. Only in one instance, viz., in our in- digenous species of Corycceus, have I found only a single ovisac, which, however, is attached quite dorsally. The Cyclopoida are well represented also in fresh water by numerous species of the genus Cyclops and allied forms, and some of the parasitic forms, for instance lA-gasilus, are also true fresh-water animals. Section 1 Gnathostoma. General Characters. — Anterior antennae in male distinctly hinged. Posterior antennae without any outer ramus, and carrying on the tip a number of curved setse. Oral parts adapted for mastication. Masticatory parts of mandibles and maxillae strongly dentate. Maxillipeds not subchelate; the posterior ones smaller than the anterior, and of the same appearance in the two sexes. Natatory legs well developed, with both rami generally 3-articulate. Bemarhs. — The several forms belonging to this section have generally been combined within a single family, the Cyclopidai. It is, however, very easy to distinguish at least 3 well-defined families of gnathostomous Cyclopoida. All these 3 families are represented in the fauna of Norway, and will be shortly characterised below. Fam. I . Oithonidae. Characters. — Body slender and of a very delicate structure, with thin and pellucid integuments. Anterior antennae in female very slender and provided with long diverging setse; those in male much more robust and distinctly geni- culate. Posterior antennae comparatively small, with the number of joints reduced. Oral parts well developed, and rather different in structure from those in other Cyclopoida, being partly armed with claw-like spines. Natatory legs with com- paratively slender 3-articulate rami edged with unusually long setse. Last pair of legs rudimentary and partly confluent with the corresponding segment. Caudal rami difiering in shape and armature in the two sexes. Remarks. — This family is founded upon the genus Oithona Baird, which in several respects differs rather conspicuously from the other genera included in the present section, and may accordingly be entitled to constitute the type of a distinct group. We do not know as yet any other genus referable to this family. The genus Mormonilla of Giesbrecht, it is true, exhibits some resemblance to Oithona in the general appearance of the body as also in the structure of the anterior antennae; but the posterior antennae are very different and built wholly on the type of the Calanoida. The systematic position of this genus is still very doubtful, though it perhaps may be found to be nearest related to the Cyclopoida, In this case it must be regarded as the type of a very anomalous family of the gnathostomous Cyclopoida. Gren. 1. Oithona, Balrd, 1843. Syn: Scribella, Dana. Generic Characters. — Body slender and attenuated, with the anterior division only slightly dilated, the posterior very narrow, linear in form. Head defined from the 1st pedigerous segment by a well-marked suture, and generally produced in front to a sharply-pointed rostrum, wanting, however, in male. Anterior antennae long and slender, scarcely tapered distally, and composed of a limited number of joints, some of which are imperfectly defined. Posterior an- tennae abruptly bent in the middle, and apparently only consisting of 2 joints, the 1st carrying about in the middle behind a short seta arising from a knob- like prominence. Mandibular palp with the basal part greatly produced, pediform, terminating in 2 claw-like spines, inner ramus represented by a very small seti- ferous appendage attached outside the basal part at some distance from its end, outer ramus well developed and abruptly reflexed, being composed of 3 — 4 joints carrying long plumose setae. Maxillae with the masticatory lobe well defined and carrying a number of sharp claw-like spines accompanied inside by a thick seti- form appendage, palp lamellar, with the outer distal lobe very small, proximal lobe well developed, recurved, and provided at the tip with long plumose setae^). Both pairs of maxillipeds slender and elongated, the anterior ones 5-articulate, the posterior ones 4-articulate, both carrying long anteriorly-curving spines. Na- tatory legs with no distinctly developed seta inside the Ist joint of the outer ramus, apical spine of this ramus very slender and serrate outside, spines of outer edge more perfectly developed in male than in female. Last pair of legs represented by a small conical joint terminating in a long seta; another similar seta issuing from a knob-like prominence on each side of the segment itself, seems to answer to that arising from the basal joint of these legs in other Cyclo- poida. Caudal rami in female strongly divergent, with the 2 middle apical setae much elongated and crossing each other at the base; those in male of quite normal appearance. Remarlcs. — The present genus was established in the year 1843 by Baird, to include a species, 0. plumifera, taken in the tropical part of the Atlantic. Another genus with the same name has been established by Alder and Hancock for a nudibranchiate Mollusc; but as this genus is of younger date than that of Baird, its name must be changed. The genus Scribella of Dana is identical with that of Baird, and likewise of later date. Several species of this genus have in recent times been described from different parts of the Oceans. Thus Dr. Griesbrecht records no less than 8 species, and some additional species have been named by other authors. There is, however, still considerable confusion about the right identification of some of these species, partly owing to their close relation and partly to the difficulty which is connected with an exact ana- tomical examination of such delicate and fragile animals. One of the species described by Dr. Giesbrecht, 0. nana, seems in some respects to differ more conspicuously from the others, and may perhaps be regarded as the type of a separate, though nearly allied genus, for which the name Oithonina may be proposed. To the fauna of Norway belong 2 well-defined species, to be de- scribed below. ^) I have formerly described these 2 lobes as the exopodal and epipodal lobes, but find that these names cannot properly be retained, since they unquestionably, as is clearly seen in the present genus, answer to the inner and outer rami of the mandibular palp. As, however, both these lobes are always attached outside the palp, I find it more appropriate to give them the indifferent names of proximal and distal outer lobes. 1. Oithona spinirostris, Claus. (PI. I & II). Oithona spinirostris, Claus, Die freilebenden Copepoden, p. 105, PI. XI, figs. 4 — 9. Syn: Oithona challengeri, Thompson, „ plumifera, Scott, (not Baird). „ atlantica, Farran. Specific Characters. — Female. Body exceedingly slender, with the anterior division narrow fusiform in shape, the greatest width scarcely exceeding Va of the length and occurring somewhat in front of the middle. No conspicuous plumes present laterally. Rostrum strong, spiniform, and only very slightly curved, so as to be visible in the dorsal aspect of the animal. Tail not much shorter than the anterior division and very narrow ; genital segment about the length of the 2 succeeding segments combined, and conspicuously dilated in its anterior part. Caudal rami nearly as long as the anal segment and rather divergent, seta of outer edge attached close to the base, the 2 middle apical setae almost twice the length of the tail. Eye narrow linear in form and of a deep red colour. Anterior antennae very slender and elongated, reaching, when reflexed, to the end of the 2nd caudal segment, and composed of about 12 more or less distinctly defined joints of rather unequal length and carrying scattered exceedingly long setae pointing in different directions. 1st pair of natatory legs with the inner ramus distinctly 3-articulate, all joints of outer ramus spiniferous outside. 2nd and 3rd pair with no spine outside the middle joint of the outer ramus, terminal joint of this ramus, as in the 1st pair, with 2 spines outside. 4th pair with no spines outside the first 2 joints of the outer ramus and with only a single setiform spine outside the terminal joint. Ovisacs narrow oblong in form and greatly divergent, in some cases extending nearly at right angles to the axis of the body, each sac containing only a limited number of very pellucid ova, generally arranged in a double row. Male much smaller than female and of a rather different appearance, the body being comparatively less slender, with the front obtusely truncate and wanting any trace of a rostrum. Tail distinctly 5-articulate, with the 1st or genital segment greatly swollen, to receive the 2 spermatophores. Caudal rami shorter than the anal segment and not at all divergent, apical setae much shorter than in female and of quite normal appearance. Anterior antennae scarcely longer than the anterior division of the body and exhibiting the usual geniculation ; middle section only slightly tumefied, terminal one biarticulate. Natatory legs with all the joints of the outer ramus spiniferous outside, 3 such spines being present on the terminal joint in the 2nd and 3rd pairs. Setse of last pair of legs much shorter than in female. Body in both sexes highly pellucid and nearly colourless, though in adult females generally a light orange pigment is seen clothing the oral area and partly also the sides of the head. A large oil-bubble is often found within the posterior part of the trunk, and 2 smaller ones at the limit between the head and the 1st pedigerous segment. Length of adult female 1.35 mm., of male 0.82 mm. Remarks. — I regard it as beyond all doubt that the above-described form is that originally recorded by Glaus under the name Oithona spinirostris. It has generally been confounded with the very nearly allied species described by Baird as 0. plumifera, from which, however, it is at once distinguished by the absence of the very conspicuous brightly-coloured plumes projecting in the latter at each side of the trunk, and from which indeed the specific name plumifera has been derived. These plumes in reality belong to the natatory legs, and are formed by the setse attached outside the 2nd basal joint of the legs, which in the said species are richly plumose, whereas in the form here under consideration they ars simple and do not even project laterally. In addition to this distinguishing character, Mr. Farran has recently pointed out some minute differences in the structure of the oral parts between these two forms, which accordingly must be regarded as distinct, though closely- allied species. Mr. Farran has proposed a new specific name for the present species, viz., atlantica, but I think that his doubt about the identity of Glaus' species with the one here under question cannot properly be approved. Occurrence. — I have observed this form in many different places on the Norwegian coast, at least up to the Trondhjem Fjord. It is, however, not nearly so common as the next species, and seems more properly to be an inhabitant of the open sea, from which it is only occasionally brought in by the currents to the shores and fjords. When kept living in a vessel with fresh sea-water, the specimens are always found freely suspended in the water, more generally in an erect attitude, with the anterior antennae and the caudal setae spread to each side, these parts apparently serving as a very effective balancing apparatus. In this attitude the animal often rests for long time nearly immobile, only now and then, by the action of the natatory legs, making a short bound to change its place. To judge from the structure of the oral parts, the animal must be of a very rapacious nature, probably feeding upon other small pelagic animals. These may at first be seized by the slender maxillipeds and by them thrown in against the 8 other oral parts, the structure of which indeed seems to be more adapted for killing than for masticating the prey. Distribution. — As this form has generally been confounded with 0. plumi- fera, its true distribution is as yet rather difficult to determine. In all probability it has a similar wide range in the Oceans to that of the next species. With full certainty it may be said to be distributed all over the North Atlantic, as also in the Mediterranean. 2. Oithona helgolandiea, Glaus. (PI. III). Oithona helgolandica, Glaus, Die freilebenden Copepoden, p. 105, PI. XI, figs, 10 — 12. Syn: Oithona spinifrons, Boeck. „ pygmcBa, Boeck. „ similis, Glaus. „ spinirostris, Giesbrecht (not Glaus). Specific Characters. — Female. Body of the usual slender form, though somewhat less so than in the preceding species. Rostrum, as in that species, acutely pointed, but abruptly bent downwards at a right angle to the axis of the body, so as not to be visible in the dorsal aspect of the animal. Genital segment somewhat less dilated in its anterior part. Caudal rami not nearly attaining the length of the anal segment, and less divergent than in 0. spinirostris, seta of outer edge shorter. Anterior antennae, when reflexed, extending scarcely beyond the anterior division of the body, and composed of about 10 joints, some of which, however, are only faintly defined. Posterior antennae and oral parts agreeing in structure with those in the preceding species. Natatory legs, how- ever, exhibiting some characteristic diiferences : 1st pair with the outer ramus armed in a manner similar to that in 0. spinirostris, except that the apical spine is less strong and almost setiform; inner ramus apparently only Particulate, the 2 outer joints being confluent. 2nd and 3rd pairs with no spine outside the middle joint of the outer ramus, though exhibiting at the end of the joint a small dentiform projection of the margin. 4th pair without any spines either on the 1st or 2nd joints. Terminal joint of this ramus in all 3 pairs with only a single small spine outside, attached close to the end, and exhibiting moreover in the 2nd and 3rd pairs a very small dentiform prominence of the margin at about the middle of the joint Ovisacs narrow oblong and closely appressed to the sides of the tail, each sac containing only a single series of very large and pellucid ova. Male closely resembling that of the preceding species, but of smaller size, and moreover differing somewhat in the armature of the natatory legs, the ter- minal joint of the outer ramus having only 2 spines outside. Body in both sexes extremely pellucid, without any obvious pigment. Length of adult female 0.70 — 0.90 mm.; of male 0.50—0.60 mm. Remarks. — There cannot in my opinion be any doubt, that the form at first recorded by Claus as 0. helgolandica is the present species. It has subse- quently been redescribed by the same author from Mediterranean specimens, but under another specific name, viz., similis, and this name has been applied to the present species by most authors. According to the rules of priority, however, the first name under which a species has been recorded should in every case be retained. The 2 forms named by Boeck 0. spinifrons and 0. pygmcea are un- doubtedly both referable to the present species, and this is also the case with the form described by Dr. Giesbrecht from the bay of Kiel as 0. spinirostris. The present species is easily distinguishable from the preceding one by the rather different form of the rostrum, the less elongated anterior antennae, and the very different manner in which the ovisacs are borne by the female. Also in the struc- ture of the natatory legs some well-marked difi'erences are found to exist, as shown in the above diagnosis. Occurrence. — This form occurs very abundantly along the whole coast of Norway, both on the outer shores and in the fjords. In the Christiania Fjord I have often taken it in great numbers even close to the beach of the innermost shallow creeks. As with the preceding species, male specimens are much scarcer than females, and seem only to appear in certain seasons. Distribution. — The distribution of this species seems to be very extensive. It has been noted as far north as in Mosel Bay, Spitsbergen, and southwards in the Mediterranean, off the Canary Islands, and even in the Indian Ocean. I have myself examined specimens taken off the coast of New Zealand, and have care- fully compared them with northern specimens, without having been able to detect any difference whatever. Fam. 2. Cyclopinidae. Characters.— Body of somewhat varying shape, but never so slender as in the Oithonidce, the anterior division being, as a rule, considerably dilated. Head in most cases confluent with the 1st trunk-segment; rostral projection short and generally bent in against the ventral face. Anterior antennae less elongated than in the Oithonidae, tapered, and clothed with moderately long setae; those in male strongly hinged. Posterior antennae generally composed of 4 joints. Oral 2 — Crustacea. 10 parts well developed and on the whole built on the same type as in the Calanoida. Natatory legs comparatively short and stout, with both rami 3 -articulate and subequal in length. Last pair of legs generally extended laterally and composed of 1 — 3 joints. EemarJcs.— The type of this family is the genus Cyelopina of Claus, which has generally been considered as closely allied to Cyclops, but which in reality differs very essentially in the structure of the oral parts, which much more resembles that found in the Calanoida. 4 different genera referable to this family will be described in the sequel. Gen. 2. CyClOplna, Claus 1863. Generic Characters. — General form of body much resembling that in the genus Cyclops. Anterior antennae more or less elongated and composed of a somewhat varying number of articulations; posterior antennje distinctly 4- articulate. Mandibles with the cutting edge divided into a number of sharp claw- like denticles, palp comparatively large, biramous, inner ramus well developed, biarticulate, outer generally multiarticulate. Maxillae with the masticatory lobe well defined and armed with several claw-like spines, palp lamellar, with both outer appendages sharply defined and carrying long plumose setae. Anterior maxillipeds rather stout, with the 2nd basal joint clawed, and the terminal part well developed, consisting of 3 joints. Posterior maxillipeds more slender, with the terminal part generally divided into 3 or 4 setiferous joints. Natatory legs of normal structure. Last pair of legs extended laterally, and composed of 2 or 3 joints, none of which are lamellar. RemarJcs.— This genus was established in the year 1863 by Claus, to include a species, C. gracilis, found by him at Messina. The genus is chiefly characterised by the Cyclops-like form of the body, and by the very full devel- opment of the mandibular and maxillary palps, which strongly recalls that in the Calanoida. Several species have been recorded by different authors; but some of these have turned out to be referable to other genera, not even belonging to the present family. In the succeeding pages 4 different species of this genus, belonging to the fauna of Norway, will be described, and I am much disposed to believe that their number will be considerably increased by a closer study of our Copepod-fauna. For instance, many years ago, off the Lofoten islands, I observed 2 peculiar forms, the one distinguished by the excessive prolongation of the I 11 caudal rami, the other by the strong development of the spines on the legs. The specimens of these 2 forms, which I had noted with the provisory names, C. longifurca and C. euacantha, have, however, unfortunately been lost, and I am thus unable to give any closer description of them here. A small species of this genus has also been described by me from the Chatham Islands under the name of C. ptisilla, and another species has recently been recorded by Th. Scott as C. longicaudata. 3. Cyelopina gracilis, Claus. (PI. IV). Cyelopina gracilis, Claus, Die freilebenden Copepoden, p. 104, PI. X, figs. 9 — 1.5. Syn: Cyelopina tiorvegica, Boeck. Cyclops salinus, Brady. Specific Characters. — Female. Body moderately slender, with the anterior division oval in form, greatest width exceeding half the length and occurring about in the middle. Tail rather slender, with the genital segment about the length, of the other 3 combined and gradually narrowed behind. Caudal rami of somewhat varying length, though scarcely longer than the last 2 segments combined, sub- linear in form and only slightly diverging, seta of outer edge placed in front of the middle; apical setae of moderate length, the inner medial one being, as usual, the longest and about equal to the tail in length; seta of inner corner scarcely longer than that of the outer. Anterior antennae not much elongated, being considerably shorter than the cephalic segment, and composed of 10 joints, the 6th of which is much the longest and about equal in length to the 4 succeeding ones combined. Posterior antennae with the last joint scarcely as long as the 2nd. Natatory legs with the spines outside the outer ramus of moderate size, 3 such spines being present on the terminal joint, except in 4th pair, where only 2 spines occur outside the apical spine. Last pair of legs biarticulate, proximal joint comparatively broad and finely ciliated inside, carrying outside the usual slender bristle, distal joint shorter and narrower than the proximal one, sub- quadrangular in form, and armed on the obtusely truncated extremity with 2 somewhat unequal lanceolate spines, between which a slender bristle is attached. Ovisacs of moderate size, oval in form, and carried closely appressed to the sides of the tail. Male of much smaller size than female, and easily distinguished by the strongly hinged anterior antennae and the distinctly 5-articulate tail, the 1st (genital) segment of which is considerably dilated. Last pair of legs of exactly the same appearance as in the female. 12 Body in both sexes of a whitish grey colour, with a faint yellow tinge. Length of adult female 0.43 — 0.57 mm. MemarJcs. — This form was rather imperfectly described by Glaus from Mediterranean specimens, and has subsequently been observed by other authors in different places of the northern Ocean. The form recorded by Boeck as C. norvegica can scarcely be regarded as specifically distinct, though it represents a strictly littoral variety, with the caudal rami comparatively shorter than in the typical form. Dr. Giesbrecht has also called attention to the variation in this respect both in the present and next species. The Cyclops salinus of Brady is unquestionably the present species, and belongs to its variety norvegica, Boeck. The specific name gracilis proposed by Glaus for the present species, is some- what inappropriate, since in reality this species is of less slender form of body than most of the other known species. Occurrence. — I have taken this form in several places on the Norwegian coast, from the Ghristiania Fjord at least up to the Trondhjem Fjord. It is a strictly littoral form, being found close to the shore among algae and scarcely ever, like the next species, at any considerable depth. The variety norvegica occurs rather frequently in shallow creeks and in pools left by the tide, both on the southern and western coasts. Distribution. — British Isles (Brady), coast of France (Canu), bay of Kiel (Giesbrecht), Franz Josef Land (Scott), Polar Islands north of Grinnel Land (2nd Fram Expedition), Mediterranean (Glaus), Black Sea (Gzerniawsky). 4. Cyelopina longieornis, Boeck. (PI. V). Cyelopina longieornis, Boeck, Nye Slsegter og Arter af Saltvandscopepoder. Clir. Vid. Selsk. Forhandl. 1872, p. 41. Syn: Cyelopina littoralis, Brady, Specific Characters. — Female. Body comparatively more slender than in the preceding species, with the anterior division oblong oval in form, greatest width about equalling half the length and occurring in the middle, cephalic segment gradually tapered anteriorly, with the front narrowly rounded. Tail very slender, almost equalling in length the anterior division, genital segment sligthly dilated in front and shorter than the 3 succeeding segments combined. Gaudal rami long and narrow, being generally longer than the 2 preceding segments combined, seta of outer edge rather slender and attached a little in front of the middle; apical setse very unequal, the inner medial one equal to the whole tail in length and fully twice as long as the outer, seta of outer corner scarcely half as long 13 ^^Vas the inner. Anterior antennae much more elongated than in the preceding ^^^ species, about equalling in length the cephalic segment, and composed of 18 well defined joints, 3rd joint much the largest, 6th joint exhibiting a slight indication ■ to be subdivided into 3 joints. Posterior antennae with the terminal joint fully m as long as the 2 preceding joints combined. Natatory legs with the seta attached inside the 1st joint of the inner ramus remarkably strong, especially in the 2 posterior pairs; terminal joint of outer ramus in 4th pair with only a single spine outside, the distal spine being replaced by a thin bristle abruptly bent inwards. Last pair of legs of comparatively feeble structure, and composed each P of 3 joints, the first 2 somewhat lamellar and finely ciliated inside, middle joint carrying outside the usual bristle, last joint comparatively small, and provided with 4 slender ciliated setae, the innermost of which is the shortest. Ovisacs of moderate size and slightly divergent. Male, as usual, smaller than female, and easily recognizable by the strongly hinged anterior antennae. Last pair of legs differing from those in female in being 4-articulate, the last joint being subdivided into 2 well defined joints, the proximal of which carries on each side a seta, whereas the distal joint has 4 setse on the tip. Body semipellucid, with scattered opaque patches of a whitish or yellow colour, in some cases, moreover, exhibiting a fine rosy tinge on several parts of the body, as also partly on the anterior antennae. Length of adult female 0.70 — 0.90 mm. BemarJcs. — This form has generally been recorded under the specific name littoralis proposed by Brady. As, however, the name longicornis, assigned to this species by Boeck, dates from the very same year, and is a much more adequate name, I have found it suitable to prefer that name to the one proposed by Brady. For the present species cannot in reality be said to be, like the preceding one, a strictly littoral form, as it more generally occurs in greater depths and is only quite occasionally met with in the littoral region. I have found that such specimens are of smaller size and have the caudal rami less elongated than in the typical form, thus more properly constituting a particular variety, for which the name littoralis may be retained. The present species is easily distinguished from the preceding one by the more slender form of the body, the much more elongated anterior antennae, and the somewhat different shape of the caudal rami. In the structural details also some well-marked differences are found, especially as regards the structure of the last pair of legs. Occurrence. — I have found this form rather frequently in many places of 14 the Norwegian coast, from the Christiania Fjord at least up to the Trondhjem Fjord. It is generally met with in depths ranging from 10 to 60 fathoms, espe- cially where the bottom consists of coarse sand; much more seldom it is found in shallower water among algse. Like the other species of the present genus, it is a true bottom-form, keeping constantly close to the ground. When disturbed, it darts away with great rapidity, to settle again very soon in another place. I have never seen it moving freely for any length of time in the water. Distribution.— British Isles (Brady), Cuxhaven (Timm), Mediterranean (Giesbrecht), Polar Islands north of Grinnel Land (2nd Fram Exped.). 5. Cyelopina brevifurea, G. 0. Sars, n. sp. (PL VI). Specific Characters. — Female. Body moderately slender, with the anterior division oblong oval in form, greatest width scarcely exceeding half the length, front evenly rounded. Tail not attaining half the length of the anterior division, genital segment comparatively large, being fully as long as the 3 succeeding seg- ments combined, anal segment shorter than the preceding one. Caudal rami very small, being scarcely longer than they are broad, seta of outer edge slender and attached about in the middle, apical setse rather elongated, the inner medial one considerably exceeding the length of the tail and, like the outer, clothed in its proximal part with coarse distant hairs, seta of outer corner unusually slender, being fully as long as that of the inner corner. Anterior antennae comparatively longer and more slender than in C. gracilis, though not quite attaining the length of the cephalic segment, and composed of 12 well-defined joints, the 6th of which is much the largest, the 6 outer joints short and all of equal size. Posterior antennae with the terminal joint about the length of the antipenultimate one. Natatory legs about as in C. gracilis. Last pair of legs, as in that species, bi- articulate, distal joint, however, comparatively larger, exceeding in length the proximal one, and narrow oblong in form, inner edge finely ciliated, tip armed with 2 slender and somewhat unequal spines, having between them a slender bristle. Ovisacs of moderate size, oval in form, and borne closely appressed to the sides of the tail. Body rather pellucid, of a whitish gray colour, with light bluish trans- parent ovaria. Length of adult female 0 60— 0.70 mm. Remarhs. — This form is closely allied to C. gracilis Claus, but differs conspicuously in the shape of the anterior division of the body, the more slender 15 and distinctly 12-articulate anterior antennse, and the remarkably short caudal rami, which latter character has given rise to the specific name here proposed. Occurrence. — I have met with this form in several distant places on the Norwegian coast, for instance at Risor on the southern coast, at Skutesnses on the south-western coast, and at Bejan outside the Trondhjem Fjord. A single well-marked ovigerous specimen was found, moreover, in a sample taken by Mr. Nordgaard in the Porsanger Fjord, Finmark. The specimens observed by me were taken in depths ranging from 10 to 30 fathoms, muddy bottom. 6. Cyelopina elegans, Scott. (PI. VII). Cyelopina elegans, Th. Scott, Addition to the Fauna of the Firth of Forth. 12th Ann. Eeport of the Fishery Board of Scotland. Part. IH, p. 237, PI. V, figs. 9—19. Specific Characters. — Female. Body very slender, with the anterior division narrow oblong in form, greatest width not attaining half the length and occurring in its anterior part, front evenly rounded. Tail almost as long as the anterior division and having the genital segment unusually large and tumid, clothed on each side with small spikes; anal segment fully as long as the preceding one. Caudal rami long and slender, equalling in length the last 2 segments combined; outer edge with 2 successive bristles, the smaller one occurring at a short distance form the base, the other attached nearer to the end and somewhat dorsally ; apical setae of moderate length, that of the outer corner shorter than that of the inner. Anterior antennse moderately slender, though not attaining the length of the cephalic segment, and composed of 18 joints, the 4th and 5th joints exhibiting, however, a more or less distinct sub-division, so that the number of joints may be increased to 20 — 21. Posterior antennse with the terminal joint scarcely longer than the antipenultimate one. Mandibular palp comparatively more slender than in the other species, with the outer ramus shorter. Posterior maxillipeds with the terminal part composed of 5 well-defined joints. 1st pair of legs, like the 3 succeeding ones, provided with 2 setae inside the middle joint pf the inner ramus, these setae being in 4th pair very coarse, almost spiniform. Last pair of legs distinctly 3-articulate, 1st joint with a coarse ciliated seta inside, middle joint rather dilated and carrying outside the usual slender bristle; terminal joint nar- row oblong in form, exceeding in length the other 2 combined, and provided outside with 2 setae, at the tip with another very slender seta and a stout spine. Ovisacs of moderate size and somewhat divergent. 16 Colour whitish grey, with a slight yellow tinge. Length of adult female about 0.80 mm. RemarJcs. — This is a very distinct species, easily recognisable both by the general form of the body and by the structure of some of the appendages. Occurrence. — The only place where I have observed this species, is at Farsund, south coast of Norway. It occurred here occasionally together with C. longicornis in a depth of about 20 fathoms, sandy bottom. Distribution.— Firth of Forth (Scott), Gulf of Naples (Griesbrecht). Gren. 3 CyClOplnella, G. O. Sars, n. Generic Characters. — General appearance resembling that in the genus Cyclopina, the anterior division of the body being considerably dilated, the posterior narrow and attenuated. Head defined from the 1st pedigerous segment by a well-marked suture. Anterior antennae comparatively short and composed of a limited number of articulations. Posterior antennae with the first joint simple and quite smooth. Mandibles short and stout, with the palp less fully developed than in Cyclopina, being simple, without any outer ramus. Maxillae likewise rather short, palp with the 2 outer appendages well developed and of about equal size, one of the apical spines, as also those of the masticatory lobe, unusually thick, almost digitiform. Anterior maxillipeds rather compact, with the claw of the 2nd basal joint scarcely different from the spines of the terminal part. Posterior maxillipeds much smaller, and of the usual structure. Natatory legs well developed differing somewhat in structure from those in Cyclopina. Last pair of legs less rudimentary than usual, being distinctly 3-articulate, with the terminal joint comparatively large and armed with strong lanceolate spines. RemarJcs. — This new genus is somewhat allied to Cyclopina, though dis- tinguished by certain apparently fundamental differences, of which may be named the distinct separation of the head from the 1st pedigerous segment, and the simple structure of the mandibular palp. Only a single species of this genus has hitherto come under my notice. 7. Cyelopinella tumidula, G. 0. Sars, n. sp. (PI. VIII). Specific Characters. — Female. Body comparatively short, with the anterior division greatly tumefied and almost pyriform in shape, the greatest width occurring 17 {ar in front and considerably exceeding half the length. Tail very narrow and tapered, with the genital segment only slightly dilated, anal segment fully as long as the preceding one. Caudal rami somewhat exceeding in length the anal seg* ment and narrow linear in form, seta of outer edge attached about in the middle, apical setae rather unequal, the inner medial one, as usual much the longest and about equalling in length the tail ; seta of outer corner quite rudimentary, that of inner attaining the length of the corresponding ramus and very thin. Eye wholly absent. Anterior antennae much shorter than the head, and composed of 12 well-defined joints, the 9th of which is somewhat longer than the others and carries a slender sensory filament. Posterior antennae with the terminal joint unusually short, not even attaining the length of the preceding one. Mandibular palp forming a simple bi-articulate stem, the distal joint of which is very small and provided with 3 curved setae. Natatory legs with no seta inside the 1st joint of the outer ramus; 1st pair with a strong spine outside the terminal joint of the inner ramus, re- placing the usual seta; spines of outer ramus in this and the succeeding pairs slender, and edged with hyaline rims, 4 such spines being present on the terminal joint in the 3 anterior pairs, 3 in that of the 4th pair, inner ramus of the latter pair unusually narrow and, like that of the 2 preceding pairs, armed at the tip with 2 spines. Last pair of legs with the 1st joint quite unarmed, 2nd carrying outside a slender bristle, terminal joint much longer than the other 2 combined, oblong quadrangular in form, and much constricted at the base, carrying outside, somewhat in front of the middle, a strong lanceolate spine and at the transversely truncated end 2 similar spines and a very small bristle between them, inner edge of the joint straight and finely ciliated. Ovisacs small, and borne closely appressed to the sides of the tail, each containing, as a rule, only 3 ova arranged in a single row. Male exhibiting the usual sexual characters. Last pair of legs of exactly the same appearance as in female. Body of the usual whitish grey colour, but appearing darker on account of the translucent, very capacious anterior part of the intestine, which is generally filled with dark brown contents. A peculiar opaque body of a whitish or pale orange hue, and transversely oval or semilunar in form, is constantly found im- mediately inside the dorsal wall of the head, in front of the intestine, and is very conspicuous in the living animal.^) Length of adult female 0.68—0.75 mm. ^) I am unable to say anything about the significance of this body. It cannot be the missing visual organ, as it does not occupy the usual place of the eye, being far remote from the front. As to structure, it seems to consist of a uniform granular matter. 3 — Crustacea. 13 Hemarics. — In its general appearance this form is rather similar to certain species of the genus Cydopina, and I was indeed at first inclined to refer it to that genus. The closer anatomical examination has, however, proved it to be in reality so different, that in my opinion it ought to be generically separated. Occurrence. — I have met with this peculiar form in several distant places on the Norwegian coast, for instance at Ris0r and Lillesand on the southern coast, at Christiansund on the western coast, and in the Trondhjem Fjord. In all places it occurred on a muddy bottom, partly covered by decaying algae, the depth ranging from 20 to 40 fathoms. Gen. 4. CyclOpetta, G. 0. Sars, n. Generic Characters. — Body somewhat depressed, with the 2 chief divisions less sharply marked off from each other than in the 2 preceding genera. Head confluent with the 1st pedigerous segment, and conspicuously contracted in front. Tail comparatively short. Anterior antennae of inconsiderable length, with the number of articulations reduced. Posterior antennae likewise unusually short and stout, and clothed with strong plumose setae. Mandibles with the palp distinctly biramous, outer ramus well developed, inner uniarticulate. Maxillae and maxilli- peds very small and difficult to examine, though apparently built on the same type as in the other Cyclopinidce. Natatory legs well developed and of normal structure. Last pair of legs consisting each of a single lamellar joint edged with ciliated setae. RemarJcs. — This new genus in some respects differs rather conspicuously from the 2 preceding ones, and seems to exhibit a certain approach to the next anomalous genus, Pterinopsyllus, though it is distinguished also from this genus by several well-marked characters. The genus is only founded upon a single species, to be described below. 8. Cyelopetta diffleilis, G. 0. Sars, n. sp. (PI. IX), Specific Characters.— Female. Body comparatively short and stout, and distinctly depressed, with the anterior division oblong fusiform in outline, greatest width scarcely exceeding half the length, and occurring about in .the middle. Cephalic segment rather large and evenly contracted anteriorly, with 19 the front narrowly rounded. Tail not attaining half the length of the anterioi* division, and scarcely tapering behind; genital segment conspicuously constricted in the middle, anal segment equalling in length the 2 preceding ones combined. Caudal rami short, not nearly attaining the length of the anal segment, and quadrangular in shape, seta of outer edge attached about in the middle, apical setse of moderate length, the inner medial one about twice as long as the outer, both coarsely ciliated, seta of outer corner much smaller than that of the inner. Anterior antennae scarcely exceeding half the length of the cephalic segment, and each composed of only 9 joints clothed with strong partly ciliated setae ; 5th joint the longest, 6th about the length of the 3 outer joints combined. Posterior antennae distinctly 4-articulate, 1st joint provided at the end on either side with a strong ciliated seta, 2nd joint with a similar seta in front, 3rd joint with 4 such setae outside, last joint about the length of the 2 preceding ones combined, and car- rying on the tip 6 anteriorly-curving and likewise densely ciliated setae. Man- dibular palp with the outer ramus composed of 4 well defined joints, inner ramus with 3 comparatively short apical setae. Proximal outer lobe of the maxillary palp much larger than the distal one and carrying 4 unusually thick plumose setae. Maxillipeds very small and densely crowded, the anterior ones apparently of normal structure, the posterior ones with the number of the terminal joints much reduced. Natatory legs not exhibiting any pronounced peculiarity in their structure. Last pair of legs consisting each of a rounded oval lamella attached outside the last trunk-segment and provided with 3 thick and curved ciliated setae; just above this lamella a thin bristle is attached to a conical projection of the segment itself. Colour not yet ascertained. Length of adult female 0.60 mm. Remarks. — The present form cannot be confounded with any of the other Cyclopinidce, exhibiting, as it does, a most characteristic appearance, somewhat recalling that found in certain of the semi-parasitic forms, to which, indeed, I was at first inclined to refer it, before having made out its anatomy. Occurrence. — Only 3 specimens of this remarkable form, all of the female sex, have hitherto come under my notice. They were picked up from a sample taken last summer at Riser, south coast of Norway, in a depth of about 40 fathoms, muddy sand. All 3 specimens have been sacrified for dissection, in order to get a satisfactory conception of the structure of the very small and densely crowded oral parts. The specific name here proposed alludes to the difficulty experienced in the examination of these parts. 20 Gen. 5. PterinOpSyllUS, Brady, 1880. Sjai : Lopliophorus, Brady (not Temminch). Cyclopella, Clans. Qeneric Characters. — Body robust and somewhat depressed, with the anterior division moderately dilated, the posterior less narrow than usual. Head coalesced with the 1st pedigerous segment, and terminating in a blunt rostrum projecting downwards. Caudal rami short, with the 2 middle apical setse very strong and densely ciliated. Anterior antennae short and stout, with the number of articulations reduced, and clothed with unusually strong pennate setse; those of male of much larger size and strongly hinged. Posterior antennae likewise short, and only 3-articulate, the last 2 joints being united. Mandibles with the cutting part considerably expanded and coarsely dentate; palp comparatively slender, with the outer ramus small and undivided, inner ramus biarticulate. Maxillae with all the constituting parts well developed. Anterior maxillipeds very stout, with 3 well-defined terminal joints armed with strong spines. Posterior maxillipeds with the terminal part very fully developed and composed of 5 joints, the 1st much larger than the others. Natatory legs strongly built, with short and blunt spines outside the outer ramus; inner ramus of 1st pair in male pre- hensile, that of 4th pair more or less reduced in female, normal in male. Last pair of legs comparatively small and not extended laterally, being composed of 3 more or less lamellar joints, somewhat different in the two sexes. RemarTcs.—T\\\'s, genus was established in the year 1878 by Prof. Brady, to comprise a peculiar Copepod found by him off the British coast. As, however, the generic name he proposed, Lophophorus, had been preoccupied for a genus of birds, he changed it in the year 1880 to Pterinopsyllas. The name Cyclojiella proposed by Glaus is of later date, and must yield to that given to the genus by Brady, The systematic position of the present genus has remained somewhat doubtful. In some respects it recalls certain genera among the Harpacticoida, and, indeed, it has been placed within that group in the list of Crustacea from Northumberland and Durham published by Norman and Brady. I think, however, that its place within the group Cyclopoida cannot at present be disputed. On the other hand, owing to the peculiarities observed in this genus, it might be thought necessary to establish for its reception a distinct family, Pterinopsyllidce. Indeed, I was at first much inclined to do so; but after having become acquainted with the preceding genus, Cydopetta, which in some respects exhibits an evident 21 approach to the one here under consideration, I find that, without any serious scruple, it may be included in the family Cyclopinidce, as here defined. In addition to the typical species described below, 2 closely-allied species, P. egregius and P. illustris, have been recorded by Dr. Giesbrecht from the gulf of Naples. 9. Pterinopsyllus insignis, Brady. (PI. X & XI). Lophophorus insignis, Brady, Monograph of British Copepoda, Vol. I, p. 1-22, PI. XIII, figs. 1 — 10, PI. XV, fig. 10. Specific Characters. — Female. Body rather stout, with the anterior division ovate in outline, greatest width exceeding half the length and occurring about in the middle. Cephalic segment large and narrowly produced in front. Last trunk-segment sharply defined from the preceding one, and projecting laterally in a small dentiform process. Tail about half the length of the anterior division, and nearly of uniform width throughout; genital segment about as long as the 3 succeeding ones combined, and scarcely at all dilated in front; anal segment shorter than the preceding one. Caudal rami quadrangular in shape, being scarcely longer than they are broad, seta of outer edge obsolete, the 2 middle apical setae very strong and divergent, with coarser and more scattered hairs on their proximal parts, seta of outer corner much smaller than that of the inner, both very thin and naked. Anterior antennae scarcely more than half as long as the cephalic segment and rather broad at the base, being composed of 8 joints, the 2nd of which is the largest, 5th joint very small. Posterior antennae clothed along the outer edge and at the tip with coarsely hairy setae, inner edge without any setae. 4th pair of natatory legs with the inner ramus much shorter than the outer, middle joint imperfectly defined from the terminal one and without any setae inside, the latter joint having inside 2 short blunt spines replacing the usual setae. Last pair of legs with the 1st joint imperfectly defined at the base, but carrying inside a well-developed ciliated seta, 2nd joint conically produced out- side and carrying the usual thin bristle, last joint much larger than the other 2 combined, and forming a rounded oval lamella coarsely ciliated inside and provided with 4 slender setae, 3 of which are ciliated, the 4th, issuing from the tip, very thin and smooth. Ovisacs, according to Brady, short pyiiform, • with a limited number of ova. Male of smaller size than female, and easily recognisable by the very coarse structure of the anterior antennae, which are powerful prehensile organs divided into 12 joints. Inner ramus of 1st pair of legs with the apical spine 22 peculiarly transformed, being abruptly bent, so as to form a claw-like prehensile appendage. Inner ramus of 4th pair of quite normal structure. Last pair of legs as in the female, 3-articulate ; the 1st joint does not, however, answer to the 1st joint in the female, but to the 2nd, as is clearly shown by the bristle issuing from its outer side. Of the other 2 joints, which accordingly answer to the terminal joint in the female, the proximal one is much the larger and carries at the end on each side a seta, whereas the distal joint is quite short with 4 diverging setae on the end. Body in both sexes of a whitish grey colour, with a slight violaceous tinge. Eye in living specimens very conspicuous and of light red colour. EemarJcs. — The present form may be easily recognised from any of our indigenous Cyclopoida, both by its characteristic outward appearance and by the rich ornament of coarsely-ciliated setse, which clothes most of the appendages. Especially are these setse very conspicuous on the anterior antennae, where they partly assume a pennate or pectinate character, giving these appendages a peculiar shruppy appearance. It was indeed to this peculiarity that the generic name, Lophophorus, at first proposed by Brady, alluded. From the 2 Mediterranean species recorded by Dr. Giesbrecht the present form cannot be distinguished without a very close anatomical examination. Occurrence. — I have met with this pretty form occasionally in 3 different places on the Norwegian coast, viz., in the inner part of the Christiania Fjord, at Ris0r, and at Flekker0, outside Christiansand. The specimens were taken in depths ranging from 20 to 40 fathoms, muddy sand. Canon Norman has taken this form also in the Trondhjem Fjord, at Rodberget, where it occurred in the considerable depth of 150 fathoms. Distribution. — Coast of England and Scotland (Brady, Scott), Gulf of Naples (Giesbrecht). Fam, 3. Cyclopidae. Characters. — General form of the body resembling that in the typical Cyclo'pinidm, the anterior division being more or less dilated, the posterior much narrower and attenuated. Head in all the known forms confluent with the Ist pedigerous^segment, and having the rostrum bent in against the ventral face. Anterior antennae more or less elongated and strongly hinged in male. Posterior antennae generally 4-articulate, with an elongated seta at the end of the 1st joint 23 posteriorly. Anterior lip with the terminal edge finely denticulate. Mandibles with the palp quite rudimentary, being reduced to a small knob-like process carrying 2 or 3 ciliated setse. Maxillae with the palp likewise imperfectly deveU oped and without any distinctly-defined outer appendages. Maxillipeds built on the same type as in the Cyclopinidce, but of comparatively simpler structure. Natatory legs, as a rule, well developed, with subequal triarticulate rami, though in some instances the number of joints in the rami may be reduced. Last pair of legs generally small and of the same appearance in the two sexes. Remarks. — This family, in the restriction here adopted, is chiefly distin- guished from the 2 preceding ones by the rudimentary condition of both the mandibular and the maxillary palps. This character is invariably found in all the forms, and must be regarded as of fundamental significance. In other respects this family exhibits a close resemblance to the Cyclojnnidce. Only a limited number of species, belonging to 2 genera, are strictly marine, whereas in fresh water we find a great number of forms, all generally referred to a single genus, viz., C^jclops. I have, however, found it appropriate to divide this extensive genus into a number of closely-allied genera (or sub- genera), which will be characterised in the next parts of the present Volume. Gen. 10. Euryte, Philippi, 1843. Syn: Thorellia, Boeck. Generic Characte7's. — Body, as a rule, rather robust, the anterior division being considerably tumefied, and sharply marked off from the slender and attenuated tail. Anterior antennae in female divided into a great number of short, but well- defined joints; those in male much more strongly built, and hinged in the usual manner. Posterior antennae rather stout, 4-articulate, with the last 2 joints comparatively short. Mandibles with the cutting edge divided into several sharp claw-like teeth, setae on the rudimentary palp not much elongated. Maxillae with the masticatory lobe well developed and armed with strong dentiform spines, palp forming an oblong lamella projecting beyond the masticatory lobe and terminating in a serrated edge, being moreover provided on each side with 2 juxtaposed setae. Anterior maxillipeds rather stout, with the digitiform lobe, issuing from the end of the 1st basal joint anteriorly, comparatively strong and, like the 2nd basal joint, projecting in a claw-like spine accompanied by a much 24 thinner seta; terminal part composed of only a single joint armed with short curved spines. Posterior maxillipeds of a somewhat unusual appearance and apparently sub-prehensile, the terminal part being abruptly bent and terminating in 2 short claw-like spines. Natatory legs powerfully developed with broad flattened basal part and the joints of the rami partly conspicuously expanded; spines of outer ramus lanceolate, bordered by broad hyaline rims finely serrated at the edges; several of the setae, both of this and the inner ramus, transformed to similar, though more delicate spines. Last pair of legs less rudimentary than usual, and resembling in structure those in the genus Cyclopinella. BemarJcs. — This genus was established by Philippi as early as in the year 1843, but was not recognised by Boeck, who records it under another name, viz., Thorellia. The genus is especially characterised by the peculiar structure of the maxillary palp and that of the posterior maxillipeds, as also by the trans- formation of several of the natatory setse on the legs to lanceolate spines. Two species of this genus have hitherto been described, both occurring off the Nor- wegian coast, and a 3rd new species is here added. All 3 species are exclusively marine. 10. Euryte longfieauda, Philippi. (PI. XII). Euryte longicauda, Philippi, Fernere Beobachtungen iiber die Copepoden des Mittelmeeres. Arch. f. Naturg. 1843, p. 63, PI. 8, fig. a—d. Syn: Tliorellia brunnea, Boeck. Cyclops, nigricauda, Norman. Cyclopina Clausi, Czerniawsky. Specific Characters. — Female. Anterior division of body rounded oval in outline, greatest width almost equalling Vs of the length, and occurring somewhat behind the middle. Cephalic segment very large, considerably longer than all the free trunk-segments combined, and evenly rounded in front. Last trunk- segment somewhat produced on each side. Tail very slender, almost attaining the length of the anterior division ; genital segment imperfectly subdivided in the middle, and exhibiting on each side a dentiform posteriorly-pointing projection; anal segment longer than the preceding one. Caudal rami very slender and elongated, equalling in length the last 3 segments combined, and sublinear in form, diverging a little in their distal parts, which appear slightly thickened; seta of outer edge attached near the extremity ; apical setae not much elongated, the inner medial one not nearly attaining the length of the tail, that of the outer Qorner shorter than that of the inner. Anterior antennae rather slender, though 25 not quite attaining the length of the cephalic segment, and composed of 21 joints, the 1st of which is much the largest; 2nd joint faintly subdivided in the middle. Posterior antennae rather strongly built, 2nd joint angularly produced at the end inside, and almost as long as the outer 2 joints combined, some of the apical setae rather strong, almost spiniforra. 1st pair of natatory legs with the inner corner of the 2nd basal joint considerably produced and carrying a strong de- flexed spine; middle joint of inner ramus very broad and, like that of the suc- ceeding pairs, provided inside with 2 setae, terminal joint with all the setae trans- formed to spines. Setae of terminal joint of outer ramus in 2nd to 4th pairs likewise transformed. Last pair of legs with the 1st joint very small and imper- fectly defined at the base, 2nd joint likewise rather small, and carrying outside the usual bristle, last joint comparatively large, oblong quadrangular in shape and somewhat curved at the narrowed base, being armed with 3 strong lanceolate spines, one of which issues a little beyond the middle of the outer edge, the other 2 from the transversely truncated extremity; between the latter, moreover, a thin bristle is attached. Ovisacs narrow oblong in form and greatly diverging. Male, as usual, smaller than female and of somewhat more slender form of body, being moreover easily recognised by the strongly hinged anterior antennae and the distinctly 5-articulate tail. Colour yellowish brown, with scattered patches of a darker hue ; proximal part of the caudal rami and the middle part of the anterior antennae generally of a similar dark hue. Length of adult female about 1.30 mm., that of male 0.90 mm. RemarJcs. — The identity of the above-described form with Philippi's Euryte longicauda has been sufficiently proved by Dr. Giesbrecht, who observed the species in about the same place, that Philippi had made his investigations in. The name Thorellia hrunnea, under which this species has been recorded by most authors, is of much later date than that given to this form by Philippi, and can- not therefore be retained. It is also beyond doubt that both Cyclops nigricauda Norman and Oyelopina Clausi Czerniawsky are referable to the same species. From the 2 next species the present one may be easily distinguished by the very long and slender caudal rami, as also by the manner in which the ovisacs are borne in the female. Occurrence. — I have found this form rather plentifully along the whole Norwegian coast, from the Christiania Fjord to Vads0 in moderate depths among algae. More particularly it seems to haunt places where the great Laminariae grow, to the leaves of which it is often found clinging rather firmly, probably by the aid of the clawed posterior maxillipeds. It moves through the water 4 — Crustacea. 26 in the usual jumping manner, and has on the whole in its behaviour much the appearance of an ordinary Cyclops. Dr. Scott records a smaller form of this species, which he designates as varietas minor. I have also myself in the inner part of the Christiania Fjord observed such small, though fully adult specimens, but have failed to detect any other differences from the typical form. Distribution. — British Isles (Brady), coast of France (Canu), Gulf of Naples (Philippi), Black Sea (Czerniawsky), eastern coast of Greenland (Buchholtz), Franz Josef Land (Scott), Polar Islands north of Grinnel Land (2nd Fram Expedition). IL Euryte robusta, Giesbrecht. (PL XIII). Euryte robusta, Giesbrecht, Mittheilungen liber Copepodeii, 12 — 14, p. 58, PI. 4, figs. 1 — 18. Specific Characters. — Female. Body comparatively more robust than in the preceding species, with the anterior division more regularly oval in outline. Tail comparatively shorter and broader at the base; genital segment exhibiting in the middle quite similar dentiform projections to those in E. longicauda. Caudal rami rather shorter than in that species, scarcely exceeding in length the last 2 segments combined, and slightly diverging at the end; apical setae more evenly ciUated, Anterior antennae, as in that species, rather slender and composed of 20 joints. Posterior antennae somewhat less robust, with the 2nd joint scarcely angular behind and the apical setae thinner. Posterior maxillipeds with the apical claws more slender and accompanied by 2 thin bristles. Structure of the legs almost exactly as in E. longicauda, though having the spines comparatively shorter and stouter. Ovisacs small and of irregularly rounded form, each containing a very limited number of ova. Male resembling that of the preceding species, but of somewhat more robust form. Body of a dark ochraceous colour, the caudal rami being tinged with deep chestnut and the anterior antennae with bands of a similar hue. Length of adult female 1.20 — 1.40 mm., of male about 1.00 mm. Remarks. — I cannot doubt that the above-described form is identical with that recorded by Dr. Giesbrecht from the gulf of Naples, though there are a few points of disagreement. Thus Dr. Giesbrecht counts 21 joints in the anterior antennae, whereas I have never found more than 20 such joints, some of which even are imperfectly defined. The figure given by him of the posterior antennae also differs somewhat, and more agrees with those antennae in E. longicauda. Otherwise, however, the two forms seem to agree perfectly. 27 The present species is closely allied to E. longicauda, but is easily distinguished by the comparatively more robust form of the body, and more particularly by the considerably shorter caudal rami. Occurrence. — I have found this form not unfrequently in several places of the Norwegian coast, for instance at Eleven and Korshavn on the southern coast, and at Aalesund and Christiansund on the western coast. It is a more pronounced deep-water form than the preceding one, being generally found in depths ranging from 20 to 60 fathoms, especially where the bottom consist of coarse sand inter- mingled with mud. It is very perplexing, that this form has not yet been ob- served off the British Isles, the Copepod-fauna of which has been so thoroughly studied, especially by Th. Scott. Distribution.— GuU of Naples (Giesbrecht). 12. Euryte eurtieornis, G. 0. Sars, n, sp. (PI, XIV). Specific Characters.— Female. Body somewhat less robust than in the preceding species, with the anterior division ovate in outline, the cephalic segment being somewhat contracted in front. Last trunk-segment less produced laterally than in the other 2 species. Tail exceeding somewhat half the length of the anterior division, genital segment with only a slight rudiment of the lateral denticles so conspicuous in the 2 preceding" species. Caudal rami about equalling in length the last 2 segments combined, and not at all diverging, tapering slightly distally; apical setae of moderate length, the 2 middle ones clothed in their prox- imal part with rather coarse and distant hairs. Anterior antennae much shorter and thicker than in the 2 preceding species, though composed of a similar great number of joints (20), most of the setae rather coarse and finely ciliated. Posterior antennae of a similar structure to that in E. rohusta. Posterior maxillipeds less abruptly curved and having the terminal part much shorter, with the apical claws extremely minute. Natatory legs built in the same manner as in the 2 preceding species, though having the rami somewhat less broad and the spines more slender. Last pair of legs likewise of a very similar structure, last joint, however, com- paratively shorter. Ovisacs rather large, and borne closely appressed to the sides of the tail. Colour not yet ascertained. Length of adult female 1.30 mm. Remarks. — This new species may be at once distinguished from the 2 preceding ones by the much shorter an stouter anterior antennae, which character 28 indeed has given rise to the sjDecific name here proposed. In the structural detail also some minor differences are found to he present, especially as regards the posterior maxillipeds and the caudal rami. Occurrence. — Several specimens of this form were collected, many years ago, at Skraaven, Lofoten islands. They occurred in a depth of about 6 fathoms, on a sandy bottom partly overgrown with algae. Gen. 11. HalleyelOpS, Norman, 1903. Syn : Hemicyclops Claas (not Boeck). Generic Characters. — Body of the usual cyclopoid shape, and somewhat depressed in its anterior part. Head confluent with the 1st pedigerous segment, and having the rostrum bent in against the ventral face. Anterior antennae short, with the number of joints greatly reduced; those in male strongly hinged. Posterior antennae with the outer 2 joints confluent. Mandibles with one of the cutting teeth much larger than the others, setae of rudimentary palp comparatively short. Maxillary palp forming a small lamella not extending beyond the masticatory lobe, and terminating in a short spine accompanied by one or two setae. Anterior maxillipeds with the digitiform lobe, issuing from the end of the 1st basal joint anteriorly, rather small and terminating in 2 unequal setae. Posterior maxillipeds imperfectly developed, being composed of 2 or 3 joints only. Natatory legs built upon the usual cyclopoid type, but having the rami not nearly so broad as in Euryte. Last pair of legs with the proximal joint more or less completely coalesced with the corresponding segment, distal joint broad lamelliform and edged with partly ciliated setae. Remarlcs. — This genus was established in the year 1893 by Glaus, to include the form generally recorded as Cyclops ceqvoreus Fischer. As, however, the name he proposed, Hemicyclops, had been preoccupied by Boeck, to designate another very different genus, not even belonging to the same section, it has been changed by Norman to Halicyclops. The genus is nearly allied to Cyclops, but differs in the imperfect development of the posterior antennae and of the posterior maxillipeds, as also in the peculiar structure of the last pair of legs. In addition to the typical form, to be described below, another nearly-allied species has been recorded by the present author from the Chatam islands as H. propinqvus, and a 3rd species, not yet described, occurs, as a true planktonic form, in the Caspian Sea. All the species are inhabitants of more or less brackish water, though they may be of marine origin, as they are never found in purely fresh water. 13. Halieyelops magnieeps (Lilljeborg). (PI. XV). Cyclops magnieeps, Lilljeborg. De crustaceis ex ordinibus tribus, etc, p. 204, PI. XXII, fig. I. Syn: Cyclops (eqvoreus, Fischer. „ christianiensis, Boeck. Specific Characters, — Female. Body moderately stout, with the anterior division oblong oval in outline, greatest width about equalling half the length and occurring somewhat in front of the middle. Cephalic segment very large and broadly rounded in front; last trunk-segment only slightly produced laterally. Tail scarcely more than half as long as the anterior division, genital segment nearly of equal width throughout, anal segment shorter than the preceding one, and deeply cleft at the end. Caudal rami about twice as long as they are broad and somewhat divergent; seta of outer edge attached about in the middle; apical setffi rather slender, the inner medial one attaining half the length of the body; seta of outer corner shorter than that of the inner. Anterior antennae compara- tively short and stout, being composed of only 6 distinctly defined joints, the first 2 rather dilated, the 3rd quite short, the 4th nearly as long as the outer 2 joints combined. Posterior antennae with the terminal joint sub-fusiform in shape, and. provided in the middle outside with a well-marked notch, indicating the place where the 2 outer joints have been coalesced. Posterior maxillipeds very small and only composed of 2 joints, the distal one much the smaller. Natatory legs with the terminal joint of the inner ramus not much larger than the middle one, and provided in the 1st pair with 2, in the other pairs with 3 spines in addition to the setae ; terminal joint of outer ramus having 3 spines outside in the 3 anterior pairs, 2 in the 4th pair. Last pair of legs with the proximal joint imperfectly defined from the segment, distal joint much expanded, spatulate in form, terminal edge obliquely truncated and carrying 4 comparatively short setae, the innermost but one simple, the others ciliated. Ovisacs oblong oval in form and borne closely appressed to the sides of the tail, each containing only a limited number of ova. Male much smaller than female, and having the anterior antennae very strongly built, being composed of 1 1 more or less distinctly defined joints, the last consituting the terminal section and produced in a sharp point. Last pair of legs with the proximal joint more distinctly defined, distal joint only differing 30 from that in female by the presence of an additional seta attached inside the others. Body semipellucid, of a whitish colour, with a very faint yellowish or greenish tinge. Ovaria and ova in the ovisacs generally of a dark blue colour. Length of adult female 0.75 mm. RemarJcs. — This form was first recorded by Lilljeborg under the name of Cyclops magniceps, but was rather imperfectly described, and, as moreover the number of joints in the anterior antennae were erroneously indicated to 8, instead of 6, the species was not recognised by subsequent authors, who generally recorded it under the specific name ceqvoreus proposed by Fischer several years afterwards. The form named by Boeck Cyclop christianiensis is also unquestionably the same species. It is distinguished from the nearly-allied form H. propinqvus G. 0. Sars by the more produced caudal rami, as also by its larger size. Occurrence. — I have found this form not unfrequently in the uppermost part of the Christiania Fjord, where it occurs close to the border of the shallow creeks in the immediate neighbourhood of the town. It also occurs in other places, both of the south and west coasts of Norway, partly in more or less brackish water. Distribution. — Kullaberg, coast of Sweden (Lilljeborg), British Isles (Brady), coast of France (Canu), Algeria (Richard), Madeira (Fischer). Gen. 12. CyClOpS, Miiller, 1776 (ex parte). Generic Characters. — Anterior division of body moderately tumid, and generally more tapered behind than in front; lateral parts of the 3 anterior trunk- segments well defined and sub-angular behind; last trunk-segment more or less produced laterally. Tail slender and attenuated, with the genital segment in female more or less dilated in front. Anterior antennae of varying length, and more generally composed of 17 well defined joints, though in some cases, by concrescence, their number may be considerably reduced ; those in male strongly hinged, with the terminal section distinctly biarticulate. Posterior antennae with all 4 joints well defined, the Ist carrying at the end posteriorly a long ciliated seta. Rudimentary palp of the mandibles carrying 2 very long and densely plumose setae accompanied by a short bristle. Maxillary palp scarcely extending beyond the masticatory lobe, and provided outside near the base with 4 ciliated setae, 3 of which issue from a slight expansion of the margin. Anterior maxilli- 31 peds moderately strong, with the 1st basal joint generally subdivided in the middle, and provided anteriorly with a small rounded lobe carrying 2 plumose setae; digitiform lobe issuing from the end of this joint anteriorly comparatively small, with none of the setae unguiform. Posterior maxillipeds much more slender, and composed of 4 well-defined joints. Natatory legs with both rami generally 3-articulate, though in some cases, by an imperfect separation of the 2 outer joints, one or other of them, or all, may be only biarticulate ; inner ramus of 4th pair with 2 apical spines. Last pair of legs very small and generally not extended laterally, being composed of 2 joints, the proximal of which in some cases may be coalesced with the corresponding segment, distal joint not expanded, and carrying a slender apical seta and a short lateral spine. Seminal receptacle in female of compara- tively simple structure, being generally transversely oval in shape. RemarJcs. — This genus is here taken in a much more restricted sense than done by other authors. Owing to the great number of species referred to this genus, it has long appeared very desirable to group them according to their mutual relationship, in order to get a clear survey on them. A such grouping of the European species has indeed been effected by Dr. Schmeil in his very valuable work on the fresh water Copepoda of Germany. I think, however that we may be justified to take a further step, and to subdivide the old genus Cyclops into a number of nearly-allied genera, each being designated by a particular name. In the present work I have attempted to do so, distinguishing 5 different genera, the name Cyclops being restricted to one of them, which comprises the greater bulk of the hitherto known species. In this genus I have included 4 of the 8 groups of Cyclopses distinguished by Dr. Schmeil, having not found sufficient reason for a generic separation of these groups; the 4 other genera answer to as many groups distinguished by Dr. Schmeil. In the restriction here adopted, the present genus is, among other things, characterised by the well defined and angular epimeral parts of the segments composing the anterior division of the body, giving to the sides of that division a more or less jagged appearance. Of the structural details, it is especially the rudimentary last pair of legs which exhibits a very characteristic appearance, conspicuously differing from that in any of the other 4 genera. A considerable number of species referable to the present genus will be described in the sequel, some of them being, however, so closely allied, that their specific distinctness has not generally been recognised. They all, like the species of the 4 succeeding genera, are exclusive inhabitants of fresh water. 3^ I'he diagnoses here given of the several species have chiefly been drawn up from adult female specimens, the males affording, as a rule, no particular characters availble for the specific distinction. 14, Cyclops StrenuUS, Fischer. (PI. XVI). Cyclops strenuus, Fischer, Bulletin de la Societe Imper. d. Nat. de Moscow, Vol. XXIV, p 419 PI. IX, figs. 12—21. Syn.i) "i Monoculus qvadricornis ruhens, Jurine. ? Cyclops pictus, Koch. „ qvadricornis, Lilljeborg. „ brevicaudatus, Glaus. „ Clausi, Lubbock. Specific .Characters. — Female. Body moderately slender, with the anterior division oblong oval in form, greatest width about equal to half the length and occurring in the middle. Cephalic segment only slightly longer than the 4 suc- ceeding segments combined, and narrowly rounded in front. Lateral parts of penultimate trunk-segment terminating in a short tooth-like projection turned somewhat outwards. Last trunk-segment angularly produced laterally. Tail some- what exceeding half the length of the anterior division ; genital segment conspicu- ously dilated in front, though the width is somewhat less than the length. Caudal rami moderately slender, exceeding in length a little the last 2 segments combined, and slightly divergent, being linear in form, and each provided dorsally with a distinct longitudinal keel, inner edge finely ciliated; seta of outer edge rather small and not much remote from the end; apical setae comparatively short, the inner medial one only very little longer than the outer and scarcely twice as long as the corresponding ramus, seta of inner corner not much longer than that of the outer. Anterior antennae of moderate length, reaching, when reflexed, to the middle of the 2nd segment, and composed of 17 joints. Natatory legs with 3 spines outside the terminal joint of the outer ramus of 1st and 2nd pairs; inner edge of same joint carrying in 1st pair 3, in the succeeding pairs 4 setae. Inner ramus of 4th pair moderately slender, with the outer apical spine some- what exceeding half the length of the inner. Last pair of legs with the distal joint not twice as long as it is broad, lateral spine rather strong and attached about in the middle of the inner edge. Ovisacs comparatively large, oval in form, and borne closely appressed to the sides of the tail. Seminal receptacle transversely truncated in front. ^) Many othei- synonyms have been given in the work of Dr. Schmeil. But as he evidently has combined several species under the name strenuus, only those synonymes are here quoted, which more strictly may refer to the species here under consideration. Oithonidse. Copepoda Cyclopoida. PI. I. G. O. Sars, del. Oithona spinirostris, Claus. Oithonidse. Copepoda Cyclopoida. PL II. G. O. Sars, del. Oithona spinirostris, Claus. (Coutiuued). Oithonigae. Copepoda Cyclopoida. PI. III. G. O. Sars, del. Oithona helgolandica, Claus. Cyclopinidae. Copepoda Cyclopoida. PI. IV. G. O. Sars, del. Cyclopina gracilis, Claus. Cyclopinidse. Copepoda Cyclopoida. PI. V. G. O. Sars, del. Cyclopina longicornis, Boeck. Copepoda Cyclopoida. PI. VI. 1 'p|i»f G. O. Sars, del. Cyclopina brevifurea, G. O. Sars. Cyclopinidse. Copepoda Cyclopoida. PI. VII. G. O. Sars, del. Cyclopina elegans, Scott. Cyclopinidae. Copepoda Cyclopoida. PI. VIII. G. O. Sars, del. Cyclopinella tumidula, G. O. Sars. Cyclopinidae. Copepoda Cyclopoida. PI. IX. G. O. Sars, del. Cyclopetta difficilis, G. O. Sars. Cyclopinidae. Copepoda Cyclopoida. PI. X. G. O. Sars, del. Pterinopsyllus insignis, Brady. Cyclopinidse. Copepoda Cyclopoida. PI. XI. G, O. Sars, del. Pterinopsyllus insignis, Brady. (Male) Cyclopidae. Copepoda Cyclopoida. PI. XII. G. O. Sars, del. Euryte longicauda, Philippi. Cyclopidse. Copepoda Cyclopoida. PI. XIII. If G. O. Sars, del. Euryte robusta, Giesbr, Cyclopidse. Copepoda Cyclopoida. PI. XIV. G. O. Sars, del. Euryte curticornis, G. O. Sars. Cyclopidae. Copepoda Cyclopoida. PI. XV. G. O. Sars, del. Halicyclops magniceps (Lilljeb.). Cyclopidae. Copepoda Cyclopoida. PI. XVI. G. O. Sars, del. Cyclops strenuus, Fischer. 33 ^K Length of adult female 1.50 — 1.70 mm. ^H Remarks. — The present species is in all probability identical with the ^form named by Jurine Monoculus quadricornis ruhens, and also Cyclops pictus of Koch may be the same species. As, however, some doubt might arise about the identity, this species has generally been recorded under the name proposed by Fischer, who indeed was the first to give a recognisable description of it. Both C. brevicaudutus, Claus and C. Clausi, Lubbock are undoubtedly referable to the present species, which may be regarded as the type of the genus Cyclops as defined here. Occurrence. — This is one of our commonest Cyclopses, being very abundant in small ponds and tarns, especially early in the spring. It is not, like most other species of the present genus, a strict bottom-form, but is generally found close to the surface of the water, swimming about rather quickly in the usual jumping manner. Male specimens are at first rather scarce, but become more numerous later in the season. Two varieties occur, the one of rather smaller size than the other and of lighter colour, and found in somewhat larger tarns. I have, however, failed to detect any other difference between the 2 forms. Distribution. — Throughout Europe, central and northern parts of Asia, Bear Island, Spitsbergen, Algeria. 15. Cyclops abyssorum, G. 0. Sars. (PI. XVII). Cyclops abyssorum, G. O. Sars, Oversigt af cle indenlandske Ferskvandscopepoder. Chr. Vid. Sel.sk. Forliandl. 1862, p. 29. Syn. : C. strenuus, var. tenuipes, G. 0. Sar.s. Specific Characters. — Female. Body comparatively more robust than in C. strenuus, with the anterior division more tumefied in its anterior part. Cephalic segment obtusely rounded in front. Lateral parts of penultimate trunk- segment terminating in a well-marked dentiform point curving outwards. Last trunk- segment acutely produced laterally. Genital segment considerably dilated in front, its greatest width exceeding the length. Caudal rami very slender and narrow, exceeding somewhat in length the last 3 caudal segments combined, and rather divergent, each having dorsally a very distinct longitudinal keel, inner edge coarsely ciliated, seta of outer edge small and attached near the end, apical setae com- paratively longer and thinner than in C. strenuus, the inner medial one almost attaining the length of the tail, seta of inner corner twice as long as that of the outer. Anterior antennae much more slender and elongated than in C. strenuus, 5 — Crustacea. 34 reaching, when reflexed, considerably beyond the 2nd segment, and having some of the marginal setse rather slender. Posterior antennae with the terminal joint longer than the penultimate one and much narrower. Anterior maxillipeds with the claw of the 2nd basal joint comparatively longer than in C. strenuus. Nata- tory legs having the same number of spines and setse as in that species, rami, however, considerably more slender, especially those of 4th pair; apical spines of inner ramus in this pair more elongated, the outer one about half as long as the inner. Last pair of legs with the proximal joint comparatively less broad than in C. strenuus^ distal joint about twice as long, and having the lateral spine of moderate size and attached nearly in the middle of the inner edge. Ovisacs smaller than in the preceding species and rounded oval in form, each containing a rather limited number of ova. Seminal receptacle comparatively small, with the anterior part evenly rounded. Colour whitish grey, with a slight yellow tinge more distinct on the tail. Length of adult female 1.80 — 1.90 mm. Remarks. — The above-described form is closely allied to C. strenuus, and has indeed by most recent authors been regarded as only a variety of that species. We know, however, at present of several species exhibiting a similar close relation- ship to C. strenuus, and together forming a natural group of Cyclopses. All of these have, it is true, been combined by Dr. Schmeil in a single species; but in recent time, the specific distinctness of some of these forms has been fully recog- nized. Thus Lilljeborg, in his account of the Swedish Cyclopses (1901), de- scribes as well-defined species the 2 forms C. scutifer, G. 0. Sars and C. vicinus, Uljanin, which are both recorded by Dr. Schmeil as only synonyms of C. strenuus. Though Lilljeborg was inclined to regard the present form as merely a "luxuri- ant" deep-water variety of C. strenuus, it is in my opinion fully as distinct from that form as are the 2 just-named species. On a closer comparison, it is in reality found to differ conspicuously from C. strenuus, both as to its outward appear- ance and the structure of some of the appendages. Among more easily observable differences I may mention the greater length of the anterior antennae, the very narrow form of the caudal rami, and the somewhat different mutual relation in the length of the apical setse. It may moreover be noted here, that the form of the seminal receptacle, on which Dr. Schmeil laid so much stress for the discrimination of species, is in the present species rather different from that in C. strenuus, as shown by the figures given in the 2 respective plates. The form recorded by me from the lake Telecki in Altai as C. strenuus, var. gracilipes, I now find to be more properly referable to the species here under consideration. I 35 Occurrence. — I first found this species in the Maridal Lake near Christiania, There it occurred only in the deepest part of the lake, at the considerable depth i{ 40 — 50 fathoms; hence the specific name proposed. Prof. Brady has taken it inder quite similar circumstances in some of the British lakes. Besides in the [aridal Lake, 1 have observed this form in the Vansj0, near Moss, and in the Jtensfjord, a branch of the great lake, Tyrifjord. In the last-named locality it jcurred rather frequently at depths varying from 6 to 12 fathoms, muddy bottom, ['he specimens from all 3 localities agree perfectly with each other, and the ^gures given by Prof. Brady show the British form also to be in full accordance rith the Norwegian one. Distribution.—S'weden (Lilljeborg), British Isles (Brady), Central Asia ([the present author). 16. Cyclops lacustris, G. 0. Sars. (PI. xvin). Cyclops lacustris, Q. 0. Sars, 1. c, p. 30. Specific Characters. — Female. Body moderately slender, with the anterior division oblong oval in form, greatest width about half the length and occurring somewhat in front of the middle. Cephalic segment comparatively large, with the frontal part almost transversely truncated. Lateral parts of penultimate trunk- segment not at all produced, being of the very same appearance as in the 2 preceding segments. Last trunk-segment likewise only very slightly prominent laterally. Genital segment of a rather characteristic form, being considerably longer than it is broad and abruptly narrowed in the middle, with the anterior part moderately dilated, the posterior part cylindric in shape. Caudal rami not attaining the length of the 3 preceding segments combined, and slightly divergent, dorsal keel obsolete, inner edge very finely ciliated, seta of outer edge small and not very far from the end, apical setse rather slender, the inner medial one attaining fully the length of the tail, seta of inner corner more than twice as long as that of the outer. Anterior antennae rather slender, reaching, when reflexed, beyond the 2nd segment of the body. Anterior maxillipeds with the claw of the 2nd basal joint unusually slender. Natatory legs exhibiting an arma- ture similar to that in the 2 preceding species, rami comparatively slender, with very long setae; outer apical spine of inner ramus in 4th pair rather small, scarcely exceeding ^/s of the length of the inner. Last pair of legs with the distal joint rather narrow, sublinear in form, lateral spine extremely minute and attached at about the middle of the inner edge, apical seta, on the other hand, 36 unusually long and slender. Ovisacs small, rounded, and each containing a ver limited number of ova. Seminal receptacle comparatively larger than in C. abys soriim, anterior part evenly rounded, posterior part rather produced. Spermatophores attached to the genital opening of about the same appearance as in C. strenuus. Body highly pellucid, with a very faint bluish or greenish tinge. Length of adult female 1.50 mm., of male 1.30 mm. BemarJcs. — In the case also of the present form the specific validity has not been admitted by recent authors, though in my opinion it is a very well-defined species. Lilljeborg was inclined to regard it as a variety of C. strenuus, which has adapted itself to a limnetic life. On a closer examination, however, the well-marked differences which this form exhibits cannot by any means be explained in this way, nor be regarded as simply accidental or varietal. Occurrence. — I have only met with this form in our 2 largest lakes, Mj0sen and Tyrifjord. It lives there as a true limnetic form together with Limno- calanus macrurus and other midwater forms, being generally found swimming about close to the surface of the water. Distribution. — Sweden (Lillj eborg) . 17. Cyclops seutifer, G. 0. Sars. (PI. XIX). Cyclops seutifer, G. 0. Sars, I. c, p. 28. Specific Characters. — Female. Body comparatively slender, with the anterior division narrow oblong in outline, greatest width scarcely attaining half the length, and occurring somewhat in front of the middle. Lateral parts of the last 2 trunk-segments greatly produced, being expanded to triangular exstant lamellae, which are more or less contiguous, so as to present, together with the corresponding segments, the appearance of a quadrangular shield obtecting the posterior part of the trunk. Genital segment comparatively large and very much dilated in front, with a small knob-like prominence on each side, posterior part gradually narrowed. Caudal rami scarcely longer than the last 2 segments combined and only very slightly divergent, dorsal keel only faintly indicated, inner edge finely ciliated ; seta of outer edge rather remote from the end, apical set* very unequal in length, the inner medial one much the longest, seta of inner corner more than twice as long as that of the outer. Anterior antennae rather slender, reaching, when reflexed, considerably beyond the 2nd segment of the body, and clothed with comparatively long setae. Posterior antennae with the terminal joint scarcely longer than the penultimate one. Anterior maxillipeds resembling in 1 _^37 tructure those in C. lacustris. Natatory legs armed as in the 3 preceding species, Imi moderately slender, the inner one in 4th pair with the outer apical spine Jry small; spines of outer ramus in all pairs rather thin; seta attached inside le 1st basal joint in 4th pair much coarser than in the other pairs. Last pair "of legs with the proximal joint comparatively small, distal joint more than twice as long, with the lateral spine of moderate size and attached somewhat beyond the middle. Ovisacs generally very small, rounded, each containing a very limited number of ova. Seminal receptacle of moderate size and evenly rounded both in front and behind. Spermatophores attached to the genital opening unusually large, projecting beyond the side of the genital segment. Body highly pellucid and generally almost colourless, in some cases, however, exhibiting a beautiful emerald green hue. Length of adult female L20 — 1.40 mm, of male LIO mm. Remarks. — This form was considered by Dr. Schmeil as only a variety of C. strenuus; but Lilljeborg has subsequently, in his account of the Swedish Cy- clopses, vindicated its specific distinctness. It is especially recognisable by the extraordinary development in the female of the epimeral plates on the last 2 trunk-segments, which gives the body a rather characteristic appearance and has indeed given rise to the specific name scutifer. Occurrence. — I have met with this form rather abundantly in several of our larger lakes, for instance in the Maridal and Lut Lakes near Christiania, where it lives as a true limnetic form. It also occurs in mountain lakes at the limit of perpetual snow, and is indeed the only Crustacean to be found there. Distribution. — Sweden (Lilljeborg), Northern part of Siberia (the present author). 18 Cyclops Vieinus, Uljanin. (PI. XX). Cyclops vieinus, Uljanin, Crustacea of the Expedition of A. Fetltschenko in Turkestan (in Eussian). p. 30, PI. X, figs. 1—7. Syn.: Cyclops strenuus, Schmeil (not Fischer). „ „ pulchellus, Brady (not Koch). Specific Characters. — Female. Body moderately slender, with the anterior division oblong oval in form and somewhat tumefied in front. Lateral parts of penultimate trunk-segment produced in the form of acutely triangular extant lappets; those of last segment likewise produced, though less so than in C. scutifer. Genital segment about as long as it is broad at the base, and gradually narrowed behind. Caudal rami long and slender, equalling in length the last 3 segments 38 combined, and only slightly divergent, dorsal keel well marked, inner edg^ minutely ciliated; seta of outer edge not very far from the end, apical setj not much elongated, the inner medial one about twice the length of the ramus, seta of inner corner more than twice as long as that of the outer. Anterior antennae comparatively shorter and stouter than in the preceding species, reaching, when refiexed, scarcely beyond the middle of the 2nd body-segment; number of joints generally only 16, the 8th and 9th joints being confluent. Posterior an- tennae with the terminal joint a little longer and narrower than the penultimate one. Natatory legs with the rami moderately slender, terminal joint of outer ramus in all pairs with only 2 spines outside; outer apical spine of inner ramus in 4th pair very small and rudimentary. Last pair of legs resembling in shape those in 6\ strenuus, the distal joint being rather short and stout, with the lateral spine well developed and attached about in the middle. Ovisacs of moderate size and oval in shape. Seminal receptacle comparatively small, resembling that in C. ahyssorum. Colour, according to Lilljeborg, somewhat variable, the body being in some cases of a unitorm whitish grey hue, in other cases tinged with brownish red or reddish yellow. Length of adult female about L70 mm. RemarJcs. — This form was first described by the Russian naturalist Uljanin, but was subsequently considered by Dr. Schmeil to be only a variety of C. strenuus. Its specific distinctness has, however, been vindicated by Lillje- borg, and I have myself, by an examination of specimens from Mongolia, had an opportunity of confirming this view. The habitus-figure given in Dr. Schmeil's work, as pointed out by Lilljeborg, evidently refers to this species, and also the form described in Prof. Brady's Monograph as C. pulchellus, is unquestionably referable to the same species. The most conspicuous character distinguishing this form from C. strenuus is the very prominent lateral parts of the last 2 trunk-segments, in which respect it somewhat resembles C. scutifer. It differs, however, very markedly both from this and the 3 other species described above, in the armature of the natatory legs, the terminal joint of the outer ramus having in all pairs only 2 spines outside. Occurrence. — This form, it is true, has not yet been observed within the limits of our country ; but I cannot doubt that, on a closer investigation, it will be found to occur at any rate in the south-eastern part of the country, since Lilljeborg has recorded it from immediately adjacent tracts of Sweden. The figures here given are from specimens found in a sample taken in the delta of 39 Volga, and kindly sent to me for examination from the Zool. Museum of St. Petersburg. Distribution.— Sweden (Lilljeborg), British Isles (Brady), Germany (Schmeil), Turkestan (Uljanin), Mongolia and Mouth of Volga (the present author). 19. Cyclops insignis, Glaus. (PI XXI). Cyclops insignis, Claus, Weitei*e Mittheilungen iiber Cyclopiden, Arcli. Nat. Hist. 23 Jahrg. Bd. 1, p. 209, PI. XI, figs. 8—13. Syn. : Cyclops quadricornis, Koch. Specific Characters. — Female. Body rather slender, though having the anterior division somewhat dilated and of regularly elliptical form, its greatest width somewhat exceeding half the length and occurring in the middle. Lateral parts of penultimate trunk-segment not produced, and of same shape as those of the 2 preceding segments. Last trunk-segment rather broad and sharply pointed on each side. Tail slender and attenuated, though shorter than the anterior division; genital segment very broad in front and abruptly constricted behind. Caudal rami long and slender, considerably exceeding in length the last 3 seg- ments combined, and narrow linear in form, being only very slightly divergent, each ramus exhibiting dorsally a very distinct longitudinal keel; seta of outer edge somewhat remote from the end, apical setse not much elongated, the inner medial one being scarcely more than twice as long as the ramus, seta of inner corner very little longer than that of the outer, which is rather strong, almost spiniform. Anterior antennse of moderate length, reaching, when reflexed, about to the middle of the 2nd segment of the body, and composed of only 14 joints, the 8th to 1 Ith joints being coalesced into a single elongate segment. Posterior antennae with the terminal joint scarcely longer than the penultimate one. Nata- tory legs more strongly built than in the preceding species, terminal joint of outer ramus in all of them having only 2 spines outside; outer apical spine of inner ramus in 4th pair less rudimentary, exceeding half the length of the inner. Last pair of legs with the distal joint rather narrow and somewhat constricted near the base, lateral spine of moderate size and attached about in the middle. Ovisacs large, oval, and carried closely appressed to the sides of the tail. Seminal receptacle short and broad, of a somewhat irregular transversely elliptical form and not produced behind. Spermatophores attached to the genital opening placed at right angles to the axis of the body. Colour yellowish, with a more or less distinct olivaceous tinge. Length of adult female amounting to 2.60 mm. 40 Remarhs — This is an easily recognisable species, though, according to the structure of the several appendages, it seems to be referable to the same group as the 4 preceding species. It is, however, at once distinguished from them by its much larger size, the 14-articulate anterior antennae, the peculiar shape of the genital segment, and the long and slender caudal rami. The C. qvadricornis of Koch seems to be this species; but as the name qvadricornis is a collective one, it cannot be maintained. The form recorded by Brady as C. insignis is scarcely that species. Occurrence.— I have taken this form in great numbers early in the spring from ponds near Christiania. Later in the summer it was not observed. Distrihution.—Sweden (Lilljeborg), Germany (Schmeil), Bohemia (Fric). 20. Cyclops vulgaris, Koch. (PI. XXII). Cyclops vulgaris, Koch, Deutschlands Ornstaceen, Myriopoden iind Arachniden, Heft 21, Tab. 4. Syn.: Monoculus qvadricornis viridis, Jurine. „ Cyclops viridis, Fischer, „ „ brevicornis, Clan.s. Specific Chm-acters. — Female. Body comparatively robust, with the anterior division rather dilated and broadly oval in form, greatest width considerably exceeding half the length Cephalic segment very large and broadly rounded in front. Lateral parts of penultimate trunk-segment of same appearance as those of the 2 preceding segments. Last trunk-segment only slightly produced laterally. Tail scarcely exceeding half the length of the anterior division; genital segment moderately dilated in front and gradually narrowed behind. Caudal rami scarcely longer than the last 2 segments combined, and only very slightly diverging, without any dorsal keel, but with the inner edge finely ciliated; seta of outer edge not very far from the end, middle apical seta^ rather elongated, the inner one attaining half the length of the body; seta of inner corner more than twice as long as that of the outer. Anterior antennae not very slender, being scarcely longer than the cephalic segment, and composed of the usual number of joints (17). Posterior antennae with the terminal joint longer than the penulti- mate one. Anterior maxillipeds more strongly built than in the preceding species. Natatory legs likewise rather strong; terminal joint of outer ramus in all of them with only 2 spines outside, inner edge of same joint in the 1st pair with only 2 setae, in the other pairs with 3 setae ; apical spines of inner ramus in 4th pair of almost equal size. Last pair of legs with the proximal joint unusually broad and conically produced outside, distal joint very small, with the lateral spine extremely minute and rudimentary. Ovisacs large, fusiform in shape, and con- 41 siderably divergent. Seminal receptacle with the anterior part transversely ellip- ^cal in form and sharply defined from the posterior part, which is exserted on iach side to a band-like stripe. Colour rather variable, in some cases bluish green, in other cases with [a distinct olivaceous tinge, and not uncommonly light whitish grey, with dark >atches at the end of the sftgments. Length of adult female amounting to 1.90 mm. Remarks. — This form has generally been recorded under the name \C. viridis Jurine. I consider it, however, to be scarcely admissible to appropriate [as specific designations the several varietal names appended by Jurine to his species iMonoculus qvadricornis and merely indicating the diversity in colour found by [him in different specimens. As moreover the colour both in the present species [and in several other Cyclopses is rather variable, the Jurinian names would in fact be of very little significance to the species. The form recorded by Koch as fC. vulgaris is unquestionably this species, and as the name viridis applied to the ispecies by Fischer is of much later date, it must cede to that proposed by Koch. ["he C. brevicornis of Claus is likewise identical with the present species. On the [other hand, the North American form named by Herrick C. viridis var. ameri- ma, is scarcely the same species, as the armature of the natatory legs is jssentially different. The present species, which belongs to the group of Cyclopses distinguished [by Dr. Schmeil as the bicuspidatus group, may be easily recognised by its |comparatively robust body, the large divergent ovisacs, and the peculiar structure )f the last pair of legs. Occurrence. — It is one of our commonest Cyclopses, and thus fully deserves the specific name proposed for it by Koch. I have met with it at all seasons )f the year, both in small ponds and ditches and in larger lakes, where it descends rather considerable depths. Distribution. — Sweden (Lilljeborg), British Isles (Brady), Germany (Schmeil), i'rance (Richard), Russia (Fischer), Central Asia and Siberia (the present author). 21. Cyclops gigas, Claus. (PI. XXIII). Wyclops gigas, Claus, Weitere Mittheilungen iiber Cyclopiden ; Arch. Nat. Hist 23 Jahrg, B. 1 p. 201, PI. XI, figs. 1—5. Syn. : Cyclops ingens, Herrick. Specific Characters. — Female. Body much larger than in C. vulgaris and of a somewhat more slender form, though otherwise exhibiting a very similar — Crustacea. 42 appearance. Caudal rami, however, conspicuously more produced, even exceedini in length the last 3 segments combined, and only very slightly divergent; middl^ apical setse rather slender, the inner one being considerably longer than the tail} seta of inner corner comparatively shorter than in C. vulgaris, not attaining twicel the length of the outermost one Both pairs of antennae of a very similar structure to that in the said species. Natatory legs likewise rather similar; apical spines of inner ramus in 4th pair, however, conspicuously more slender. Last pair of legs, as in C. vulgaris, with the proximal joint rather expanded and conically produced outside, distal joint, however, comparatively narrower, with the lateral spine almost obsolete. Ovisacs very large and of a somewhat irregular form, projecting far beyond the caudal rami, and less divergent than in C. vulgaris. Seminal receptacle with the anterior part comparatively larger than in that species, occupying almost the whole width of the genital segment. Colour light yellowish brown, with a more or less distinct olivaceous or greenish tinge. Length of adult female amounting to 2.50 mm. Remarhs. — This form has been considered by Dr. Schmeil and several other authors to be only a large variety of the preceding species. Lilljeborg has, however, vindicated its specific distinctness, and I have myself, by a careful com- parison, come to the same result. It may be at once distinguished from C, vul- garis, not only by its unusually large size, but also by the much more produced caudal rami, and by the somewhat different mutual relation in the length of the apical setse. The last pair of legs also, though somewhat resembling those in the said species, differ slightly in the shape of the distal joint. Finally, the seminal receptacle is of a somewhat different shape, as shown by the figure here given. The North American form C. ingens of Herrick seems to be referable to the present species. • Occurrence. — I have taken this form in great abundance from some small ponds near Christiania. The specimens were observed early in the spring, even before the ice was wholly melted, and as all of them at that time were fully grown and to some extent thickly covered with Epizoa, they must have developed at a much earlier period, during the winter. Later in the spring their number decreased gradually, and at the approach of the summer they seemed wholly to have disappeared. The species also occurs in some of our larger lakes and more generally in very considerable depths. In Lake Mj0sen I have even taken it at the great depth of 100 fathoms ; and though most of the specimens there obtained were immature, they could with full certainty be adduced to the present species, on account of the considerably produced caudal rami. Lilljeborg has found the species under quite similar circumstances in some of the Swedish lakes. 43 Distribution. — Sweden (Lilljeborg), British Isles (Brady), Germany (Glaus), jear Island (Lilljeborg), North America (Herrick). 22. Cyclops capillatus, G. 0. Sars. (PL XXIV). Cyclops capillatiis, G. O. Sars, 1. c, p. 39 Specific Characters. — Female. Body not very slender, resembling some- what in its general form that in C. vulgaris, anterior division regularly elliptical in outline, with the greatest width somewhat exceeding half the length and occurring |in the middle. Lateral parts of penultimate trunk- segment of same shape as those on the 2 preceding segments. Last trunk-segment comparatively small, not jroduced laterally. Genital segment resembling in shape that in C. vulgaris, being about as long as it is broad at the base. Caudal rami comparatively slender, almost attaining the length of the last 3 segments combined, and not at all divergent; seta of outer edge rather slender and far from the end, being attached near the middle; middle apical setse slender, the inner one attaining half the length of the body; seta of inner corner scarcely longer than that of the outer. Anterior antennae about the length of the cephalic segment, and composed of only 12 joints, the 7 short articulations intercalated in other species between the 7th and the antepenultimate joint being in the present form by concrescence reduced to 2 elongated segments; lateral setse of the antennae un- usually long and slender. Posterior antennae with the terminal joint considerably longer than the penultimate one. Natatory legs moderately slender, terminal joint of outer ramus in all of them armed outside with 3 spines, inner edge of same joint in 1st pair with 3, in the other pairs with 4 setae; inner ramus of 4th pair very narrow, with the terminal joint fully as long as the other 2 com- bined, apical spines of this ramus slender and elongated, the inner one slightly longer than the outer. Last pair of legs with the proximal joint rather broad and expanded, distal joint much smaller, rounded oval in form and having the lateral spine very small. Ovisacs narrow fusiform in shape and greatly diverging. Seminal receptacle with the anterior part transversely oval and evenly rounded in front, posterior part only slightly produced. Colour yellowish, with a more og less distinct olivaceous or brownish tinge. Length of adult female about 1.80 mm. RemarJcs. — This is a very distinct species, though in size and general appearance somewhat resembling C. vulgaris. From this species it is, however, markedly distinguished by the smaller number of joints in the anterior antennae, 44 the structure of the caudal rami, and the rather different armature of the nata- tory legs. Occurrence. — I have found this form only quite occasionally in 3 different localities, viz., in the Maridal Lake near Christiania, in MJ0sen and in Tyri^ord. In all 3 localities it occurred at a depth of from 2 to 6 fathoms on a muddy bottom. Distribution. — Sweden (Lilljeborg). 23. Cyclops lueidulus, Koch. (PI. XXV). Cyclops lueidulus, Koch, 1. c. Heft 21, 10. Syn. : Cyclops vernalis, Fischer. „ „ elongatus, Glaus. „ „ parcus, Herrick. Specific Characters. — Female. Body comparatively slender and attenuated, with the anterior division oblong oval in form, greatest width about half the length and occurring somewhat in front of the middle. Lateral parts of the pedigerous segments rather prominent, those of penultimate segment terminating in a tooth-like projection curved outwards. Last trunk-segment rather broad, and acutely produced on each side. Genital segment conspicuously dilated in front and gradually tapered behind. Caudal rami rather long and slender, equalling in length the last 3 segments combined, and scarcely at all divergent; seta of outer edge attached not far from the end, middle apical setae long and slender, the inner one exceeding the length of the tail; seta of inner corner very thin and somewhat longer than that of the outer, which is rather thick, spiniform. Anterior antennae scarcely longer than the cephalic segment, and generally com- posed of the normal number of joints (17), though in some cases 18 joints may be counted, on account of a subdivision of the 7th joint. Posterior antennae with the terminal joint about the length of the penultimate one. Natatory legs com- paratively strongly built, with the spines rather coarse and varying somewhat in number, the terminal joint of the outer ramus having in some cases 3 spines outside in one or other of the pairs instead of the usual number (2); setae of inner edge of this joint in 1st pair 2, in the other pairs 3; apical spines of inner ramus in 4th pair subequal in size. Last pair of legs very small, proxiroal joint not much dilated, distal joint narrow, with the lateral spine of moderate size and attached near the end. Ovisacs comparatively large, oval in form, and only slightly diverging. Seminal receptacle transversely elliptical in form, and 45 scarcely produced at all behind. Spermatophores attached to the genital opening small and placed longitudinally close together. Colour light yellowish, with a more or less distinct reddish or ochra- ceous tinge. Length of adult female 1.40 — 1.50 mm. Remarks. — I have thought it right to maintain my original identification of this form with C. luddulus of Koch, in spite of the controversy of Dr. Schmeil. It is true, that the description given by Koch of this species, as pointed out by Dr. Schmeil, is quite insufficient, but nevertheless I find it possible to recognise the species from the figure accompanying the description, and Dr. Eehberg is also of opinion that my identification is correct. The species has generally been recorded under the name vernalis proposed for it by Fischer ; but this name is of much later date than that given to the species by Koch. The Cyclops elongatus of Glaus is certainly the same species, and this is also the case with the North American form C parens, Herrick, of which I have had specimens for examination kindly sent to me by Prof. Forbes- From the 3 preceding species it is easily distinguished by its slender elongated body, rather resembling in this respect some of the succeeding species, especially G. pulchelhis and C. hisetosus. It is, how- ever, well distinguished also from these species by several well-marked characters, as shown hereafter. Occurrence —The present species is found rather commonly throughout the whole country in shallow pools and ditches. Especially early in the spring it abounds in nearly all the ponds round Christiania, but is also met with, though not so frequently, at other seasons. A smaller variety is often found having the caudal rami somewhat shorter, but otherwise agreeing with the typi- cal form. Distribution. — Throughout Europe, Central Asia, New Siberian Islands, Ceylon, North America. 24. Cyclops robustus, G. 0. Sars. (PI. XXVI). Cyclops rohustus, G. 0. Sars, 1. c, p. 36. Syn.: Cyclops brevispinosus, Herrick. Specific Characters. — Female. Body considerably more robust than in the preceding species, with the anterior division rather dilated and oval in form, greatest width exceeding half the length and occurring about in the middle. Cephalic segment very large and evenly rounded in front. Lateral parts of 46 penultimate trunk-segment conspicuously produced, each terminating in a sharp, somewhat extant point. Last trunk-segment likewise acutely produc d laterally. Genital segment longer than it is broad at the base, anterior part slightly dilated. posterior sub-cylindrical in shape. Caudal rami comparatively shorter and les narrow than in C. lucidulus, not attaining the length of the last 3 segments combined, and scarcely divergent ; seta of outer edge rather coarse and somewhat remote from the end; apical setae unusually strong, almost spiniform, the inne: medial one nearly attaining half the length of the body and, like the outer on quite smooth in its proximal half, the remaining part being clothed with shor coarse hairs; seta of inner corner only slightly longer than that of the outerj Anterior antennae scarcely as long as the cephalic segment, and composed of the normal number of joints (17). Posterior antennae with the terminal joint not longer than the penultimate one. Natatory legs comparatively strongly built; terminal joint of outer ramus in all of them armed outside with 3 coarse spines and having the normal number of setae inside; seta attached outside the terminal joint of the inner ramus in 1st pair of normal appearance, in the other pairs, however, transformed into a strong denticulated spine ; apical spines of same ramus in 4th pair subequal in size. Last pair of legs somewhat resembling those in C. vulgaris, the proximal joint being considerably expanded, and the distal joint of inconsiderable size, with the lateral spine very minute. Ovisacs of moderate size and oval in form, being only slightly divergent. Seminal receptacle trans- versely elliptical in form, and only very slightly produced behind. Colour light yellowish brown. Length of adult female 1.20 mm. Remar'ks. — 'Dv. Schmeil does not admit the specific validity of this form, which he only regards as a variety of the preceding species. I think, however, that it ought to be kept apart, and Lilljeborg has also, in his account of the Swedish Cyclopses, described it as a well-defined species. It may indeed readily be distinguished from C. lucidulus by its much more robust body, for which reason also the specific name robustus was proposed by the present author. In the structural details also several well-marked diffeiences are found to exist, as shown in the above-given diagnosis. According to Lilljeborg, the North American form C. hrevispinosus Herrick is identical with the present species. Occurrence. — This form seems in our country to be of rather rare occur- rence. I have only met with it quite occasionally at the border of 3 of our larger lakes, viz., the NordsJ0 Lake, Maridal Lake and MJ0sen. In habits it is a true bottom-form, keeping constantly close to the ground. Distnhution.—Svfeden (Lilljeborg), North America (Herrick). ai i 47 25. Cyclops pulehellus, Koch. (PI. XX VII). Cyclops pulchelltis, Koch, 1. c. Heft 21, 2. Syn. : Cyclops bicuspidatus, Claus. „ „ Lubbocki, Brady. „ „ insignis, Brady (not Claus). „ „ odessanus, Schmankewilsch. „ „ helgolandicus, Rehberg. Specific Characters. — Female. Body rather slender and attenuated, with {he anterior divison oblong oval in outline, greatest width about equalling half the length and occurring in the middle. Lateral parts of penultimate trunk- segment not extant, resembling in shape those of the 2 preceding segments. Last trunk-segment only slightly produced laterally. Genital segment comparatively large and gradually narrowed behind. Caudal rami long and slender, generally attaining the length of the last 3 segments combined, and not at all divergent; seta of outer edge at a considerable distance from the apex, being attached not far from the middle of the corresponding ramus ; middle apical setae rather slender, the inner one being much the longer and about equalling the tail in length; seta of inner corner very little longer than that of the outer, and much thinner. Anterior antennae about the length of the cephalic segment and gener- ally 17-articulate; in some instances, however, by the concrescence of the 8th to nth joints, only l4-articulate. Posterior antennae with the terminal joint slightly longer and narrower than the penultimate one. Natatory legs comparatively slender, with only 2 spines outside the terminal joint of the outer ramus; apical spines of inner ramus in 4th pair rather unequal, the outer one being much the larger. Last pair of legs with the proximal joint comparatively small, distal joint more than twice as long, and narrow linear in form, lateral spine rather slender and attached at a short distance from the end. Ovisacs generally narrow oblong or fusiform in shape, and considerably diverging. Seminal receptacle with the posterior part rather produced. Colour generally yellowish, with a more or less distinct orange or reddish tinge, in some instances, however, uniformly whitish grey. Length of adult female amounting to L30 mm. RemarTcs, — My original identification of this form with G. pulehellus of Koch has not been admitted by Dr. Schmeil, and the present species has there- fore by most recent authors, and also by myself, been recorded under the name bicuspidatus given to it by Claus. I now find, however, that there are so many things which speak in favour of my former identification, that I have thought it right to maintain it here. It must indeed be assumed that Koch has observed 48 this rather common Cyclops, and no other species can properly be identified with his C. pulchellus than the present one. The C. Thomcm of Forbes, which both by Dr. Schmeil and Lilljeborg is recorded as only a synonym of the present form, is in reality a well-defined species, as I have convinced myself by an examination of specimens kindly sent to me by Prof. Forbes. The form at first described by Prof. Brady as C. Luhbocki and subsequently as C. insignis Glaus, seems to be referable to the variety odessana of the present species, and this is also the case with C. helgolandicus of Rehberg. I have been in some doubt as to whether the said variety should not more properly be regarded as a separate species, as it differs from the typical form not only in the smaller number of joints in the anterior antennae, but also in the comparatively shorter caudal rami, and in a somewhat difi'erent shape of both the inner ramus of the 4th pair of legs and of the last pair of legs, as shown in the accompanying plate. The characteristic position of the seta on the outer edge of the caudal rami, as also the mutual relation of the innermost and outermost apical setae, is, however, exactly as in the typical form, and I have also found in some instances, that the elongate 8th joint of the anterior antennae exhibits distinct traces of a subdivision into the usual 4 short articulations. Occurrence.— The present species is found not unfrequently in ponds and ditches round Christiania, especially in the spring. I have also met wath it occasionally at the border of larger lakes, or in pools left by the reflux of the water. In the living state it is easily recognised from the allied species by the considerably diverging ovisacs, the ova of which often exhibit a light reddish colour, as indicated in the figure given by Koch- The variety odessana I have taken early in the spring from small water-holes with grassy bottom, the water of which very soon evaporated. Distribution. — Throughout the greater part of Europe, Central Asia (G. 0. Sars), North America (Herrick). 26. Cyclops bisetOSUS, Rehberg. (PI. XXVIII). Cyclops bisetosus, Rehberg, Beitrag zur Kentniss der freilebenden Siisswasser-Copepoden. Abliandl. nat. Verein zu Bremen, Bd. VI, Heft 3, p. 543. Syn. : Cyclops bicuspidatus, G. O. Sars (not Claus). Specific Characters. — Female. Body still more slender and attenuated than in the preceding species. Lateral parts of penultimate trunk-segment not extant. Last trunk-segment slightly produced laterally. Genital segment rather 49 iraid, being scarcely longer than it is broad. Caudal rami narrow and some- lat tapered, being about as long as the last 3 segments combined and not at 11 diverging; seta of outer edge not far from the apex, middle apical setae slender, the inner one exceeding the length of the tail; seta of inner corner very small, shorter than that of the outer. Anterior antennae scarcely as long as the cephalic segment, and l7-articulate. Posterior antennae with the terminal joint a little longer than the penultimate one. Maxillipeds of the usual structure. Natatory legs exhibiting a similar armature to that in the preceding species; rami, however, comparatively shorter ; terminal joint of inner ramus in 4th pair scarcely longer than the middle one, and having the outer apical spine shorter than the inner. Last pair of legs somewhat resembling those in C. pulchellus, though having the distal joint comparatively shorter and the lateral spine less produced. Ovisacs rather largie, oval in form, and only slightly divergent. Seminal receptacle with the anterior part surrounded by a clear area forming on each side an auricular corner, posterior part somewhat produced and evenly rounded. Colour whitish grey, with a more or less distinct redjdish or brownish tinge. Length of adult female 1.00 to 1.25 mm. Remarks. — This form was formerly erroneously identified by the present author with C. biciispidatus Glaus, which belongs to the preceding species. It has subsequently been described by Dr. Rehberg as C. bisetosus, and this name is now generally adopted for the present species. In its external appearance it has a general resemblance to C. pulchellus, but is of somewhat smaller size, and is moreover distinguished by some differences in the structure of the caudal rami and legs, as also in the manner in which the ovisacs are carried in relation to the axis of the body. Occurrence. — This species is by no means uncommon. I have taken it in many parts of the country, and always in very shallow pools and ditches, which are subjected to more or less complete exsiccation during the summer. Distribution. — Sweden (Lilljeborg), Germany j^Schmeil), Siberia (G. 0. Sars), Spitsbergen (Richard). 27. Cyclops erassieaudis, G. 0. Sars. (PI. XXIX). Cyclops erassieaudis, G. O. Sars, 1. c, p. 40. Specifie Characters. — Female. Body less slender than in the preceding species, with the anterior division oblong oval in form, greatest width about half the length and occurring somewhat in front of the middle. Lateral parts of the trunk-segments somewhat prominent. Last trunk-segment rather broad, 7 — Crustacea. 50 being produced on each side to an acuminate projection pointing outwards. Tail comparatively short and thick, exceeding only very slightly half the length of the anterior division; genital segment unusually dilated throughout its whole length, exhibiting a slight constriction in front of the middle. Caudal rami of moderate size, about equalling in length the last 2 segments combined, and scarcely at all divergent; seta of outer edge not far from the apex, middle apical setse slender, the inner one exceeding the length of the tail; seta of inner cornei extremely small and rudimentary, scarcely more than half as long as that of th^ outer. Anterior antennae about the length of the cephalic segment, and com- posed of only 12 joints, the 8th and 9th joints, as in C. capillatus, answering to] the 7 short articulations succeeding the 7th joint in other species. Posterior] antennae and maxillipeds about as in the preceding species. Natatory legs un- usually short and stout, with the joints of the rami broad and expanded, number] of spines and setse as in the 2 preceding species; inner ramus of 1st pair with' the apical spine unusually strong and somewhat curved, that of 4th pair with the terminal joint scarcely longer than the middle one, and having the inner apical spine longer than the outer. Last pair of legs resembling in shape those in C. hise- tosus. Ovisacs rather large, oblong oval in form, and slightly divergent. Seminal receptacle with the anterior part somewhat expanded laterally, posterior part only slightly produced. Spermatophores attached to the genital opening of quite unusual size, kidney-shaped and placed close together longitudinally to the axis of the body. Colour uniformly whitish grey. Length of adult female 0.90 — 1.10 mm. Remarks. — This form ranges among the smaller species of the present genus, and may readily be recognised by its comparatively short and stout tail, which character indeed has given rise to the specific name proposed. In the structural details also it exhibits several well-marked differences from the species described in the preceding pages. Occurrence. — I have taken this form occasionally in shallow pools and ditches near Christiania. It is not very active in its motions, and in this respect somewhat resembles the next species. Distribution. — Sweden (Lilljeborg), Bohemia (Schmeil). 28. Cyclops langvidus, G. 0. Sars. (PI. XXX). Cyclops langvidus, G-. O. Sars, 1. c, p. 40. Specific Characters. — Female. Body moderately slender, with the anterior division oval in form, greatest width somewhat exceeding half the length and 51 !„._ _. ^^ne same shape as those of the 2 preceding ones. Last trunk-segment only slightly ^^roduced laterally. Tail of moderate length, with the genital segment rather large, though evenly contracted behind. Caudal rami almost attaining the length of the last 3 segments combined, and very slightly divergent; seta of outer edge somewhat remote from the apex ; middle apical setse slender, the inner one some- what exceeding the tail in length; seta of inner corner extremely small and rudimentary, that of outer corner normally developed. Anterior antennae about equal in length to the cephalic segment, and composed of only 16 joints, the 3rd and 4th joints being confluent. Posterior antennae with the terminal joint longer than the penultimate one. Maxillipeds rather short and stout, though otherwise exhibiting the usual structure. Natatory legs to some extent imperfectly developed, both rami of 1st pair being only biarticulate, and the inner ramus of 2nd pair likewise biarticulate, outer ramus of this pair, on the other hand, as also both rami of the 2 succeeding pairs, distinctly 3-articulate; terminal joint of outer ramus in these pairs provided outside with 2 spines, inside with 3 setae; apical spines of inner ramus in 4th pair comparatively short, the inner one being the longer. Last pair of legs distinctly biarticulate, resembling in structure those in C. pulchellus, the distal joint being rather slender, sublinear in form, with the lateral spine attached close to the end. Ovisacs generally of very large size, reaching in some cases far beyond the caudal rami, and somewhat divergent; Seminal receptacle with the anterior part transversely elliptical in form, posterior part very little produced. Colour uniformly whitish grey. Length of adult female about 1.00 mm. Remarks. - This form was described by the present author as early as the year 1863, and has subsequently been also observed by some other authors. It is chiefly distinguished from the species described in the preceding pages by the imperfect development of the 2 anterior pairs of natatory legs, agreeing in this respect with the 2 succeeding species. From the latter it may be readily recognised by its comparatively larger size, by the greater number of joints in the anterior antennae, and by the normally developed last pair of legs. Occurrence. — 1 have met with this form occasionally in shallow pools and ditches near Christiania, especially in the spring. The movements of the animal, when alive, are very slow and are not, as usual, effected by abrupt jumps, but more resemble an even course through the water, during which the body turns now 52 the right, now the left side upwards. This peculiar mode of movement has indeed given rise to the specific name proposed. Distribution.— Sweden (Lilljeborg), Germany (Schmeil), France (Richard). 29. Cyclops diaphanus, Fischer. (PI. XXXI). Cyclops diaphanus, Fischer, Beitrage ziir Kennitniss der in der Umgegend von St. Petersburg sich findenden Cj^clopiden (Fortsetzung). Bulletin Soc. Imp. Moscow; Vol. XXVI, p. 93, PI. Ill, figs. 6—12. Syn. : Cyclops nanus, G. 0. Sars. „ „ minutus, Glaus. Specific Characters. — Female. Body somewhat more slender than in the preceding species, with the anterior division less dilated, the greatest width scarcely exceeding half the length. Lateral parts of penultimate trunk-segment resembling in shape those of the 2 preceding segments. Last trunk-segment very slightly produced laterally. Genital segment comparatively large and protuberant below, being longer than it is broad at the base, and gradually contracted behind. Caudal rami scarcely attaining the length of the last 3 segments combined and not at all divergent; seta of outer edge at a considerable distance from the apex, being attached almost in the middle; inner medial seta much longer than the outer, and attaining almost half the length of the body ; seta of inner corner, as in C. langvidus, very small and rudimentary. Anterior antennae scarcely as long as the cephalic segment, and composed of only 1 1 joints. Posterior antennae and maxillipeds about as in the preceding species. Natatory legs, as in that species, imperfectly developed, both rami of the 1st pair and the inner one of the 2nd pair being only biarticulate; rami of the 2 succeeding pairs of normal structure and comparatively more slender than in C. langvidus; apical spines of inner ramus in 4th pair rather elongated, the inner one attaining fully the length of the terminal joint. Last pair of legs extremely small, with the proximal joint imperfectly defined from the segment, distal joint narrow linear in form, with a very small lateral spine near the apex. Ovisacs of moderate size and only very slightly divergent. Seminal receptacle resembling in shape that in C. langvidus. Body rather pellucid, with a faint yellow or reddish tinge. Length of adult female 0.70 — 0.90 mm. Remarhs. — Lilljeborg has pointed out that the species originally described by the present author as C. nanus, is in reality identical with that recorded by Fischer at a somewhat earlier date under the name C. diaphanus, and that the C. minutus of Glaus is referable to the same species. Dr. Schmeil, who, how- 53 I I^Ber, had not himself had an opportunity of examining the species, placed it, together j^H^ C, gracilis Lilljeborg, in a separate group of Cyclopses (his gracilis-diaphanus ^group). This arrangement cannot, however, be accepted. The 2 said species are in reality very different, though apparently agreeing as to the number of joints in the anterior antennae and the imperfect development of the last pair of legs. I am inclined to refer C. gracilis, which, however, I unfortunately have not myself had an opportunity of examining, to the succeeding genus, Mesocydqjs, whereas the present species is unquestionably a genuine Cyclops, and indeed so closely allied to C. langvidus, that Dr. Schmeil was inclined to regard my C. nanus, which as above stated is only a synonym of C. cliaphanus, as merely a variety of C. langridus, the latter being referred by that author to his ^bicuspidatus group". The specific distinctness of the present form cannot, however, by rights be disputed, as it differs from C. langvidus, not only in its much smaller size, but also in the smaller number of joints in the anterior antennae, the imperfect development of the last pair of legs, and finally in the shape of the caudal rami. Occurrence. — I have only met with this form in a few places near Chri- stiania, viz., in some shallow grassy pools lying close to the border of a large lake, the Sognsvand, and apparently left by the reflux of the water in the lake. A single specimen was also found last summer in Mj0sen, near Hamar, at a depth of about 4 fathoms. Distribution. — Sweden (Lilljeborg), Germany (Glaus), Russia (Fischer). 30. Cyclops abyssieola, Lilljeborg. (PI. XXXII). Cyclojis abyssieola, Lilljeborg, Svenska Arterna af SI. Cyclops. Kongl. 8v. Vet. Akad. Handl. Bd. 35, No. 4, p. 66, PI. IV, figs. 16—19. Specific Character's. — Female. Body comparatively short and stout, with the anterior division regularly oval in outline, greatest width considerably exceed- ing half the length and occurring in the middle, frontal part narrowly rounded. Lateral parts of the trunk-segments only slightly prominent and rounded off at the end. Last trunk-segment very small and scarcely produced laterally. Genital segment, on the other hand, of unusual size, exceeding in length the 3 succeeding segments combined, and considerably dilated in front, being conspicuously broader than the last trunk-segment. Caudal rami not much produced, being scarcely longer than the last 2 segments combined, and not at all divergent; seta of outer edge not far from the apex and attached somewhat dorsally; middle apical setae rather strong and somewhat unequal, the inner one being much the larger 54 and nearly equalling the tail in length; seta of inner corner very small, that of the outer about twice as long and spiniform. Anterior antennae short and stout, not nearly attaining the length of the cephalic segment, and composed of only 10 joints thickly clothed with coarse diverging setse. Posterior antennae likewise unusually short, with the 3 outer joints nearly equal in length. Maxillipeds alsc comparatively short and stout, especially the anterior ones. Natatory legs, as ii the 2 preceding species, imperfectly developed, both rami of 1st pair and the' inner one of 2nd pair being biarticulate ; spines of outer ramus unusually long and slender, especially those in the 1st pair; seta attached outside the terminal joint of inner ramus in all the pairs spiniform; apical spines of this joint in 4th pair rather produced, the inner one being somewhat longer than the outer. Last pair of legs extremely small and attached to the outer corners of the last trunk- segment, proximal joint confluent with the segment, distal joint narrow, sublinear in form, with the lateral spine issuing from the apex itself, immediately inside the apical seta. Ovisacs, according to Lilljeborg, of small size. Seminal receptacle rather large, with the anteriot part very broad, forming on each side a rounded expansion, posterior part somewhat produced, linguiform. Colour whitish, with a faint rosy or violaceous tinge. Length of adult female 0.75 mm. RemarJcs. — This is a very distinct and easily recognisable species, differing conspicuously in its outward appearance from those described in the preceding pages, and somewhat recalling certain species of the genus Platycyclops, especially P. ftmbriatus (Fischer). It is, however, a genuine Cyclops, as shown by the struc- ture of the legs, and in this respect closely approaches the 2 preceding species. Occurrence.— ^QmQ specimens of this pretty form were taken last summer in MJ0sen, near Hamar, from a depth of 4 — 6 fathoms, muddy bottom. According to Lilljeborg, it descends in some instances to considerably greater depths, having been found by that author in one of the Swedish lakes (Ifsjo) down to 25 fathoms. It was indeed for this reason that the specific name ahyssicola was proposed. Distribution. SwediQu (Lilljeborg). 31. Cyclops varieans, G, 0. Sars. (PI. XXXIII). Cyclops varieans, G. 0. Sars, 1. c".. p. 43. Syn.: Cyclops orientalis, Uljanin. Specific Characters. — Female. Body not very slender, with the anterior division oval in form, greatest width somewhat exceeding half the length and 55 I I^Bcurring about in the middle. Cephalic segment comparatively large and evenly rounded in front. Last trunk-segment somewhat produced laterally. Tail only slightly exceeding half the length of the anterior division; genital segment con- spicuously dilated in front and gradually narrowed behind. Caudal rami about the length of the last 2 segments combined and scarcely divergent ; seta of outer edge somewhat remote from the apex, middle apical setae rather slender, the inner one considerably longer than the outer, and about equalling in length the tail and last trunk-segment combined; seta of inner corner very thin, though consider ably longer than that of the outer. Anterior antennae comparatively short, not attaining the length of the cephalic segment, and only composed of 12 joints. Posterior antennae with the last joint scarcely longer than the penultimate one. Anterior maxillipeds short and stout, with the claw of the 2nd basal joint almost straight. Natatory legs with both rami in all the pairs biarticulate, 4th pair, in the living animal, generally projecting to each side of the trunk; inner ramus of this pair with both apical spines well developed, the outer one about half as long as the inner. Last pair of legs with the proximal joint wholly confluent with the segment, its seta springing off from the lateral corner, distal joint small, narrow conical in form, and having an extremely minute spinula in the middle of the inner edge, apical seta rather slender. Ovisacs comparatively large, oblong in form, and somewhat divergent. Seminal receptacle small, rounded, exserted on each side to a narrow band-like stripe. Colour whitish, with a fainte yellow or reddish tinge. Length of adult female 0.70 — 0.90 mm. Remarks. — This species, together with the succeeding one, is included by Dr. Schmeil in a particular group of Cyclopses (his varicans-bicolor group), chiefly characterised by the biarticulate rami on all the natatory legs, and the imperfect development of the last pair of legs. The same characters are also exhibited by some exotic Cyclopses. Thus, of the several species described by the present author from the lake Tanganyika, Central Africa, C. attenuatus, C. Cunningtoni and C. pachycomus belong to this group. The same is also the case with the Australian species, C. Arnaudi, G. 0. Sars. Finally the form recorded by Dr. Lepeschkin as C. diaphanus, var. dengizica represents another species of the said group. According to the statement of Dr. Schmeil the C. orientalis ofUljaninis identical with the present species, and I am also of opinion, that the C. ruhellus of Lilljeborg can hardly be distinguished specifically. Occurrence. — This form seems to be of rare occurence in our country. I have only met with it in some grassy ponds near Christiania. The specific name varicans alludes to the peculiar manner in which the 4th pair of natatory 66 legs are borne in the living animal, these legs being constantly extended laterally to each side of the trunk, without apparently partaking in the movements of the, other pairs. Distribution. —Sweden (Lilljeborg), Germany (Schmeil), Poland (Lands) Turkestan (Uljanin), Central Africa (G. 0. Sars), New Zealand (G. 0. Sars),] North America (Herrick). * 32. Cyclops bieolor, G. 0. Sars. (PI. XXXIV). Cyclops bieolor, G. O. Sars, 1. c, p. 44. Syii.: Cyclops (Raphmius, Rehberg (not Fischer). Specific Characters. — Female. Body comparatively short and stout, with the anterior division oval in form, greatest width slightly exceeding half the lenght and occurring about in the middle. Last trunk-segment less produced laterally than in C. varicans. Tail rather slender, equalling ^A of the length of the anterior division ; genital segment only slightly dilated in front and gradually tapered behind, its anterior parts rather protuberant below. Caudal rami about the length of the last 2 segments combined and of linear form, being not at all divergent; seta of outer edge not far from the apex, the 2 middle apical setae remarkably thick and densely covered with cilia, the inner one only slightly longer than the outer and much shorter than the tail; seta of inner corner about twice as long as that of the outer and much thinner. Anterior antennae still shorter than in C. varicans, only slightly exceeding half the length of the cephalic segment, and composed of only 11 joints. Posterior antennae with the last joint considerably longer than the penultimate one. Maxillipeds agreeing in structure with those in C. varicans. Natatory legs, as in that species, with both rami in all the pairs biarticulate; 4th pair rather smaller than the preceeding pairs, and having the rami comparatively narrow, outer apical spine of inner ramus very small and rudimentary, inner spine long and slender. Last pair of legs still more reduced than in C. varicans, its proximal joint wholly coalescent with the segment, distal joint extremely small, without any trace of a lateral spine. Ovisacs of moderate size and carried closely appressed to the tail. Seminal receptacle transversely ellipti- cal in form and almost occupying the whole width of the genital segment. Colour rather peculiar, the anterior division of the body being, as a rule, nearly colourless, whereas the whole tail and the anterior antennae exhibit a beautiful golden yellow or orange hue. Length of adult female scarcely exceeding 0.60 mm. Cyclopidae. Copepoda Cyclopoida. PI. XVII. G. O. Sars, del. Cyclops abyssorum, G. O. Sars. Cyclopidae. Copepoda Cyclopoida. PI. XVIII. G. O. Sars, del. Cyclops lacustris, G. O. Sars. Cyclopidae. Copepoda Cyclopoida. PI. XIX. G. O. Sars, del. Cyclops scutifer, G. O. Sars. Cyclopidae. Copepoda Cyclopoida. PI. XX. G. O. Sars, del. Cyclops vicinus, Uljanin. Cyclopidae. Copepoda Cyclopoida. PI. XXI. Q. O- Sars, del. Cyclops insignis, Claus. Cyclopidae. Copepoda Cyclopoida. PI. XXII. G. O. Sars, del. Cyclops vulgaris, Koch. Cyclopidse. Copepoda Cyclopoida. PI. XXIII. G. O. Sars, del. Cyclops gigas, Claus. Cyclopidae. Copepoda Cyclopoida. PI. XXIV. G. O. Sars, del. Cyclops capillatus, G. O. Sars. Cyclopidae. Copepoda Cyclopoida. PI. XXV. G. O. Sars, del. Cyclops lucidulus. Koch. Cyclopidae. Copepoda Cyclopoida. PI. XXVI. G. O. Sars, del. Cyclops robustus, G. O. Sars. Cyclopidae. Copepoda Cyclopoida. PI. XXVII. G. O. Sars, del. Cyclops pulchellus, Koch. Cyclopidse. Copepoda Cyclopoida. PI. XXVIII. // /' e^ re if i 1 1/1 -A^ I I A. V ' ■• > If7^ G. O. Sars, del. Cyclops bisetosus, Rehberg. Cyclopidae. Copepoda Cyclopoida. PI. XXIX. v;M>. ^ ^JjIl-' J 2 and composed of 2f) joints, terminal part biarticulate. Posterior antennae with the penultimate joint scarcely more than half as long as the preceding one; rudi- mentary outer ramus remote from the end of the latter joint, being attached nearly at the middle of its posterior edge. Oral cone extending only to the insertions of the posterior maxillipeds, and gradually tapered. Mandibles with the mas- ticatory part moderately slender, and distinctly denticulated inside the tip; palp with only a single apical seta. Maxillse with the outer lobe a little shorter than the inner, and much narrow^er, apical seta rather elongated and accompanied by a small hair. Claw of anterior maxillipeds very slender and distinctly subdivided in the middle, outer part evenly curved. Posterior maxillipeds, as usual, more elongated than the anterior ones. Natatory legs of rather feeble structure, the rami, especially in the 4th pair, being unusually narrow. Last pair of legs with the proximal joint well defined from the segment, and produced inside to an acuminate process; distal joint very long and slender, sabre like, and» extending far beyond the middle of the genital segment, outer edge produced, at some distance from the end, to a dentiform projection, the apical part, beyond the process, being provided with 3 or 4 small bristles. Male, as usual smaller than female, and of still more slender shape. Anterior antennae composed of 19 joints, the last 2 of which admit of being bent upon the adjoining part. Last pair of legs differing somewhat from those in female, the distal joint being comparatively shorter and almost claviform in shape, and moreover provided with 2 additional blunt spines inside. Genital lobes bipartite. Body in both sexes very pellucid and nearly colourless. Length of adult female amounting to 0.8.5 mm., of male to 0.68 mm. Remarks. — As mentioned above, this form was first described by Brady as a species of his genus Cyclopicera. It was subsequently justly removed from that genus by Canu and placed in the new genus Collocheres established by that author. According to the same author, the Ascomyzon comatulce of Rosoll is identical with the present species. Occurrence. — I have hitherto only met with this form in a single locality, viz., at Ris0r, south coast of Norway, where a few specimens were taken from a depth of about 30 fathoms among dredged material. Rosoll found this form parasitic on Comatula mediterranea. Distribution.— British Isles (Brady), coast of France (Canu), Triest (Rosoll), Gulf of Naples (Giesbrecht). 10^ Gen. 22. MeSOChereS, Norm. & Scott, 1905. Generic Characters. — Body slender and elongated, with the anterior division only slightly dilated. Cephalic segment less deep than in Collocheres with the rostrum comparatively small. Epimeral parts of the trunk-segments slightly produced. Tail slender, and composed in female of only 3 segments. Caudal rami long and narrow. Anterior antennae slender, resembling in structure those in Ascomyzon. Posterior antennae moderately strong, with the penultimate joint comparatively short. Oral cone very little produced. Mandibles with the masticatory part comparatively short, tapered and minutely denticulated inside the tip; palp small, uniarticulate. Maxillse with the lobes likewise rather small, the inner one being the larger. Anterior maxillipeds distinguished by the pre- sence of a secondary spine at the base of the claw. Posterior maxillipeds of normal structure. Natatory legs rather strongly built, with the spines unusually broad, dagger-like. Last pair of legs very small, biarticulate, distal joint tri- angular in shape. RemarJcs. — With regard to the general form of the body and the long and narrow caudal rami, this genus somewhat recalls the preceding one, from which it is, however, at once distinguished by the different segmentation of the tail, in which respect it agrees with the genus Ascomyzon. In the other structural details also, several peculiarities are found to exist, fully justifying the establish- ment of the present genus. It comprises as yet only a single species, to be described below. 60. Mesoeheres anglieus, Norm. & Scott. (PI. LXIV). Mesoeheres angliciis, Norm. & Scott, Crustacea Copepoda new to science, Ann. & Mag. Nat. Hist. Ser. 7. Vol. XV, p. 298. Specific Characters. — Female. Anterior division of body oblong oval in outline, with the greatest width about equalling half the length. Cephalic seg- ment large and narrowly rounded in front, epimeral edge gently curved; rostrum acutely produced below. Lateral parts of the 3 succeeding segments somewhat angular behind. Last segment very small, scarcely broader than the genital segment. Tail somewhat shorter than the anterior division, and very narrow; genital segment about the length of the other 2 combined, and slightly dilated J(j4_ in its anterior part, which projects on each side to a hamiform, posteriorly- pointing process; anal segment much smaller than the preceding one. Caudal rami exceedingly long and slender, linear, attaining about the length of the remaining part of the tail, and only very slightly divergent; outer edge very finely ciliated, inner smooth, tip transversely truncated; apical setae comparatively short, the innermost hut one scarcely longer than the corresponding ramus. Anterior antennae not quite as long as the cephalic segment, and composed of 21 well-defined joints, terminal part distinctly 3-articulate. Posterior antennae with the penultimate joint scarcely half as long as the preceding one; rudimentary outer ramus attached close to the end of the latter joint. Oral cone very short, almost globular in form, its extremity being obtusely blunted and only extending to the insertions of the anterior maxillipeds. Mandibles and maxillae pointing almost straight inwards. Anterior maxillipeds with the claw rather slender and evenly curved in its outer part, basal spine rather strong and likewise curved. Posterior maxillipeds comparatively slender. Natatory legs with the number of setje about as in Ascomyzon : spines distinguished by their broad dagger-like form and the coarse denticulation of their edges. Last pair of legs with the proximal joint well defined and of the usual appearance, distal joint rounded triangular in form and provided with 2 small apical bristles and 2 lateral ones, that of the outer edge the longer. Ovisacs, in the specimen examined, very small,' each containing only 3 ova, arranged in a single row. Body of a clear whitish colour, partly tinged with reddish orange; ovarial tubes dark green. Length of adult female about 1 mm. Male unknown. Bemarlcs. — This form was first anounced under the above name by Norman & Scott in the year 19()5 from a single female specimen taken in Plymouth Sound. In the following year this specimen was redescribed and figured in detail by the same authors in their work on the Crustacea of Devon and Cornwall. Occurrence. — Only a few female specimens of this form have hitherto come under my notice. They were taken, many years agO; in the upper part of the Christiania Fjord from a depth of about 30 fathoms among dredged material. Distribution. — British Isles (Norman & Scott). Cyclopidae Copepoda Cyclopoida PI. XLIX G. O. Sars, del. Platycyclops affinis, G. O. Sars Cyclopidae Copepoda Cyclopoida PI. L G. O. Sars, del. Platycyclops fimbriatus, (Fischer) Ascomyzontidae Copepoda Cyclopoida PI. LI G. O. Sars, del. Ascomyzon asterocheres, Boeck Ascomyzontidae Copepoda Cyclopoida PI. LII G. O. Sars, del. Ascomyzon asterocheres, Boeck (continued) Ascomyzontidse Copepoda Cyclopoida PI. LIII G. O. Sars, del. Ascomyzon Lilljeborgi, Thorell Copepoda Ascomyzontidae Cyclopoida PI. LIV G. O. Sars, del. Ascomyzon Boecki, (Brady) Ascomyzontidae Copepoda Cyclopoida PI. LV G. O. Sars, del. Ascomyzon simulans, Scott Ascomyzontidae Copepoda Cyclopoida PI. LVI G. O. Sars, del. Ascomyzon latum, (Brady) Ascomyzontidae Copepoda Cyclopoida PI. LVII G. O. Sars, del. Ascomyzon parvum, (Giesbrecht) Ascomyzontidae Copepoda Cyclopoida PI. LVIII a.'. G. O Sars, del. Echinocheres violaceus, Claus Ascomyzontidae Copepoda Cyclopoida PI. LIX G. O. Sars, del. Dermatomyzon nigripes, (Brady) Ascomyzontidae Copepoda Cyclopoida PI. LX G. O. Sars, del. Dermatomyzon nigripes, (Brady) (continued) Ascomyzontidae Copepoda Cyclopoida PI. LXI G. O. Sars, del. Rhynchomyzon purpurocinctum, (Scott) Ascoinyzontidse Copepoda Cyclopoida PI. LXII G. O Sars, del. Rhynchomyzon rubrovittatum, G. O. Sars Copepoda Ascomyzontidae Cyclopoida PI LXIII ^'^^'^"^^'^^^^^^^^-^ G. O. Sars, del. Collocheres gracilicauda (Brady) Ascomyzontidae Copepoda Cyclopoida PI. LXIV G. O. Sars, del. Mesocheres anglicus. Norm. & Scott 105 Gren. 23. LeptOITiyZOn, Gr. 0. Sars, n. Sync Collocheres, A. Scott (part). Generic Characters. — Body slender, with the anterior division very little dilated. Cephalic segment with the inferior edges considerably curved in front; rostral projection very slight and obtuse at the tip. Epimeral plates of the succeeding segments rounded off. Tail very slender, and composed in female of 4 well-defined segments; genital segment without any lateral projections. Caudal rami somewhat produced, though far less slender than in the 2 preceding genera, outer seta more or less remote from the apex, dorsal bristle, however, occupying its usual place near the end of the ramus. Anterior antennae slender, with the full number of articulations. Posterior antennae resembling in structure those in Collocheres. Oral cone short and stout, carrying at the obtuse apex 2 remark- able diverging tentacular appendages, apparently attached to the posterior lip. Mandibles rather strong, with the apex distinctly denticulate, palp small, con- sisting of a narrow cylindrical joint, carrying on the tip a ciliated seta. Maxillae with the inner lobe well developed and furnished at the end with 4 rather strong setae; outer lobe much narrower, but of about the same length, and provided with only a single apical seta. Maxillipeds with the dactyli extremely slender, that of the anterior ones distinctly biarticulate. Natatory legs well developed, with the rami comparatively broader than in Collocheres ; their armature about as in that genus. Last pair of legs distinctly biarticulate, proximal joint forming inside a lingui- form expansion, distal joint rather large, oblong, and extending backwards along the genital segment. RemarTcs. — The present new genus is established to include the form described by A. Scott as Collocheres elegans. This form, it is true, exhibits some characters in common with the type of the genus Collocheres, but differs in other particulars so materially, that in my opinion it ought to be kept apart as the type of a distinct, though nearly-allied genus. The chief differences are found in the structure of the oral cone, the last pair of legs and the caudal rami. In addition to the type species described below, the form recorded by A. Scott from Ceylon as Collocheres Gieshrechti is undoubtedly referable to the present genus. 61. Leptomyzon elegans, (A. Scott). (PI. LXV). Collocheres elegans, A. Scott. Report for 1895 of the Lancashire Sea-Fislieries Lahoratoriiini, p. 52, PI. V, figs. H— 15. Specific Characters. — Female. Body exceedingly slender and elongated, with the anterior division oblong fusiform in outline, greatest width scarcely 14 — Crustacea. 106 exceeding half the length. Cephalic segment somewhat longer than the 4 suc- ceeding segments combined, and narrowly rounded in front. Tail slender, almost attaining the length of the anterior division; genital segment rather large, exceeding in length the 3 succeeding segments combined, atid slightly dilated in its anterior part. Caudal rami rather produced, being about the length of the last 2 segments combined, and somewhat lamellar, with the outer part shghtly narrowed, inner edge finely ciliated; outermost seta at a considerable distance from the apex, and attached to a distinct ledge on the exterior margin, innermost seta slender, exceeding the corresponding ramus in length; the inner mediate one about half the length of the tail. Anterior antennae nearly as long as the cephalic segment, and composed of 21 joints, the outer 3 constituting the ter- minal part. Posterior antennae with the outer ramus very small and attached about in the middle of the very slender 2nd joint. Natatory legs of a similar structure to that in Collocheres gracilicauda, but more strongly built, especially the 4th pair. Last pair of legs scarcely extending beyond the middle of the genital segment; inner expansion of proximal joint obtusely triangular in form, unarmed; distal joint oblong oval in form, with the inner edge straight, outer gently curved and minutely ciliated, tip obliquely truncated and provided with 3 small bristles. Body rather pellucid, of a whitish grey colour. Length of adult female 0.87 mm. Male unknown. Remarks. — This form, as already mentioned, was described by A. Scott as a species of the genus Collocheres, the characteristic structure of the oral tube having escaped his attention, as also the difference in the arrangement of the caudal setae. Occurrence.— A few female specimens of this form were collected, many year^ ago, at Eggesb0naes, west coast of Norway, from a depth of about 20 fathoms. Distribution.— OS Port Erin, west coast of Scotland (A. Scott). Gen. 24. ScOttOChereS, Giesbrecht 1897. Syu: Acontiophorus. Scott (part). Generic Characters. — Body of a similar slender form to that in the 3 preceding genera, the anterior division being only slightly dilated. Cephalic segment scarcely compressed, its inferior edges being quite evenly curved; rostrum 10? wholly absent. Epimeral parts of the 3 succeeding segments rounded orf. Tail composed in female of only 3, in male of 4 segments. Caudal rami not much produced, in some cases very short, with all the setae originating from the end. Anterior antennae resembling in structure those in the other Ascomyzontidas, though having the number of joints somewhat reduced ; those in male distinctly hinged and provided with supplementary sesthetasks. Posterior antennae of the usual appearance. Oral cone, however, rather peculiar and somewhat similar to that in the next family, being produced into a very narrow, more or less curved siphonal tube. Mandibles without any palp, and having the masticatory part extremely slender, setiform. Maxillae with the lobes very unequal in size, each carrying 3 setae. Maxillipeds comparatively slender, with the dactyli exceedingly narrow, that of the anterior ones distinctly biarticulate. Natatory legs well developed, with the rami comparatively broad and equal-sized; their armature differing slightly from that in the other genera. Last pair of legs of moderate size, biarticulate, proximal joint broadly expanded inside, distal joint lameliiform. Remarks. — This genus was established by Giesbrecht, to include the form at first described by Scott as Acontiophorus elongatus. The differences of this form from the true Acontiophori have been duly pointed out by Giesbrecht. Indeed, the only character by which it seems to approach that genus, is the structure of the siphon. Otherwise it agrees fairly well with the other Ascomy- zontidoe, and of course ought to be included in that family as here defined. In addition to the type species described below, Giesbrecht records another nearly- allied form from the Bay of Naples under the name of S, longifurca. 62. Seottoeheres elongatus, (Scott). (PI. LXVI). Acontiophorus elongatus, Scott, Aim. & Mag. Nat. Hist., Ser. 6, Vol. XII, p. 145, PI. IX, figs. 15—20. Specific Characters. — Female. Body comparatively narrow and elongated, with the anterior division oblong in form, greatest width scarcely exceeding half the length. Cephalic segment of moderate size and obtusely rounded in front, without any trace of a rostral projection below. The 3 succeeding segments gradually diminishing in size, with the epimeral parts not very prominent. Tail scarcely exceeding half the length of the anterior division ; genital segment com- paratively large, occupying more than half the length of the tail, and somewhat dilated in its anterior part, with a slight prominence on each side, just in front of the genital orifices; anal segment very small, scarcely half as long as the 108 preceding segment. Caudal rami short, quadrangular in form, being scarcely longer than they are broad, and transversely truncated at the end; apical setse of moderate length, the outer mediate one remarkably thickened in its middle part. Anterior antennae not nearly attaining the length of the cephalic segment^-, and rather narrow, being composed of 17 joints sparingly clothed with com-^ll paratively small setae, proximal division well marked off from the distal one, terminal part uniarticulate. Posterior antennae with the 2nd (basal) joint rather slender, rudimentary outer ramus attached near the end of this joint; terminal joint very small, but with the apical spine rather strong. Siphon extending about to the end of the anterior division of the body, being, as a rule, conspicuously curved, and in preserved specimens often split up into its two components, the anterior and posterior lips. 1st pair of natatory legs with the spine, issuing from the 2nd basal joint inside, lanceolate in form; terminal joint of outer ramus with only 2 setae inside, distal spine of outer edge well developed, the other 2 very small. Same joint in 2nd and 3rd pairs with 4, in 4th pair with 3 setae inside. Terminal joint of inner ramus in 1st pair with a conspicuous dentiform projection inside the tip; same joint in 4th pair with only a single apical spine. Last pair of legs with the inner expansion of proximal joint broadly rounded, unarmed; distal joint oval in form, with the edges minutely ciliated and the tip provided with 3 comparatively short setae, the middle one spiniform. Male resembling the female in the general shape of the body, but of smaller size, and having the tail composed of 4 well defined segments, the 1st of which is considerably swollen, to receive the comparatively large globular sperraatophores. Anterior antennae much more powerfully developed than in female, though composed of a smaller number of joints, viz., 15, the last 2 of which form together a movable terminal section, which admits of being bent upon the somewhat thickened adjoining part of the antenna. Body (in female) rather pellucid, with a faint orange tinge, and with the translucent ovarial tubes of a somewhat darker hue. Length of adult female about 1 mm., of male 0.70 mm. Remarlcs. — This form, as mentioned above, was at first described by Scott as a species of the genus Acontioj)horus. apparently on account of the somewhat similar structure of the siphon. Its generic difference has however subsequently been admitted by that author, and it was redescribed under the above name in the sixteenth Annual Eeport of the Fishery Board for Scotland, From the nearly-allied Neapolitan species, S. longifnrca Giesbr., it is easily distinguished by the very short caudal rami. 109 Occurrence. — A few female specimens of this form were collected, many years ago, at Eggesbonaes, west coast of Norway, and some additional specimens, among them a single male, were recently picked up from the residue of the same collecting bottle, in which, as mentioned above, several species of Ascomyzon were found. Distrihutmi.— Bv\i\^\\ Isles (Scott), Bay of Naples (Giesbrecht), Ceylon (A. Scott). Fam. 5. Acontiophoridae. Characters. — General form of body resembling that in the Ascovnyzontidm, the anterior division being more or less dilated, the posterior one attenuated. Anterior antennae not much produced, and densely clothed with partly ciliated setae, no distinct boundary being found, as in most of the Ascomyzontidce, between the proximal and distal portions; a small terminal part, however, distinguishable, formed by the outermost joints succeeding that carrying the usual aesthetask. Posterior antennae rather unlike those in the Ascomyzontidm, the terminal joint being much more fully developed and provided with several spines and setae; outer ramus comparatively large, though uniarticulate. Oral cone produced into a very narrow siphonal tube somewhat resembling that in Scottocheres. Mandibles with the masticatory part imperfectly developed, terminating in a simple hair- like point, which does not extend to the end of the tube; palp replaced by a single very large and densely plumose seta. Maxillae with the basal part unusu- ally large and massive, lobes more or less curved downwards and provided with richly ciliated setae. Maxillipeds of the usual structure. Natatory legs likewise on the whole normally built. Last pair of legs comparatively small, with the proximal joint imperfectly defined; distal joint scarcely lamellar, and provided with several spiniform setae. Remarks. — This family is established to include the genus Acontiophorus of Brady, which seems to me to differ in some respects so materially from the preceding genera comprised within the family Ascomyzontidos, that it can hardly be associated with them. The structure of the posterior antennae and the oral parts, in particular, is very unlike that found in the true Ascomyzontidce. I am inclined to believe that the 2 hitherto known species, A. suctatus and ornatus, should more properly be regarded as types of 2 nearly-allied genera, as their outward appearance is rather dissimilar, and some of the structural details also 110 seem to exhibit differences of more than specific value. In any case, the species described below, as the first one recorded, ought to be regarded as the type of the genus Acontiophorus. Gen. 25. ACOIltiOphOrUS, Brady 1880. Syn: Solenostoma, Brady (preoccupied). Generic Characters. — Anterior division of body moderately dilated, not depressed. Epimeral parts of the trunk-segments not produced, but evenly rounded off. Tail composed in female of 3, in male of 4 segments, none of them pro- duced at the postero-lateral corners. Caudal rami of moderate size, and trans- versely truncated at the end, apical setae well developed. Anterior antennae very short, with the number of joints considerably reduced; those in male imperfectly hinged, and provided with supplementary aesthetasks. Posterior antennae with the terminal joint rather large and scarcely narrowed distally, outer ramus attached close to the end of the 2nd (basal) joint, and cylindrical in form. Siphon exceedingly slender and elongated. Maxillae with the inner lobe larger than the outer, and carrying on the tip 4 setae, the 2 inner of which are densely plumose. Maxillipeds quite normal. Natatory legs with the rami comparatively slender and subequal in length; their armature resembling that in the gen. ScoUocheres. Last pair of legs very small ; distal joint provided with 5 rather unequal setae. BemarJcs. — The above-given generic diagnosis chiefly refers to the type species A. scutatus. The other species referred to this genus. A, ornatus, differs more or less in some of the characters here given, and should in my opinion, as noted above, more properly be removed to a separate, though closely-allied genus. 63. Aeontiophorus scutatus, Brady. (PI. LXVII). Aeontiophorus scutatus, Brady, Mouogr. of British Copepoda, Vol. Ill, p. 69, Pi. XC, figs. 1 — 10. Syn: Solenostoma scutatum, Brady & Roberts. Specific Characters. — Female. Body moderately slender, obpyriform in shape, with the anterior division broadly ovate, greatest width considerably ex- ceeding half the length. Cephalic segment very large, occupying nearly half the length of the body, and quite evenly rounded in front; rostral projection extremely small, almost obsolete. Tail scarcely exceeding in length Va of the anterior Ill division and having all the segments quite simple; genital segment about the •length of the 2 succeeding segments combined and slightly dilated in front. Caudal rami sublinear in form, being about 3 times as long as they are broad, and scarcely at all divergent; apical seta3 more or less curved outwards in their distal part, the inner mediate one exceeding the tail in length. Anterior antennae short and rather thick at the base, tapering distally, and composed of only 11 joints clothed with slender spreading setae, 1st, 2nd and 6th joints larger than the others ; terminal part 3-articulate. Posterior antennae fully as long as the anterior ones, and having the 2nd (basal) joint comparatively large and slightly curved in the middle, terminal joint exceeding somewhat in size the preceding one, and carrying on the blunted end 2 comparatively large spines of unequal length and finely denticulated on the edges, these spines being moreover accom- panied inside by a slender ciliated seta, and outside by a somewhat shorter seta and a minute bristle; outer ramus somewhat longer than the terminal joint and provided with a long apical seta and another much shorter lateral one. Siphonal tube exceedingly long and slender, extending almost to the end of the body. Maxillae with the outer lobe originating far in front and considerably curved, carrying on the tip 3 moderately long plumose setae accompanied outside by a minute bristle. Maxillipeds moderately strong, dactylus of the anterior ones only slightly curved and imperfectly subdivided in the middle; basal part of the posterior ones composed of 2 well-defined joints. Natatory legs with the spines of the outer ramus narrow lancet-shaped; terminal joint of this ramus in 1st and 4tb pairs with 3 setae inside; terminal joint of inner ramus in 3rd and 4th pair with only a single spine on the tip. Last pair of legs with the distal joint rather small, rounded oval in form, and carrying inside 2 short setae, outside 2 much longer setae attached close together to a distinct ledge and partly crossing each other, and at the somewhat exserted tip another similar seta. Ovisacs oblong in form, and closely appressed to the tail, each containing a rather limited number of ova, in some cases only 4 arranged in a single row. Male considerably smaller than female, and exhibiting the usual sexual differences. Anterior antennae composed of the same number of joints as in the female, though their mutual relation is rather different; terminal part consisting of only a single narrow lamellar joint; assthetask issuing from the preceding joint very largely developed. Colour (in female) generally light yellowish brown, with darker intestine and ovarial tubes. Length of adult female about 1 mm. 112 BemarJcs.— This form was at first recorded by Messrs. Brady and Robertson under the name of Solenostoma scutatum. The generic name being however preoccupied, it was redescribed and figured by the former author in his monograph under the above name. It is a very distinct and easily recognizable form, especially distinguished by the unusually short anterior antennae and the extraordinary development of the siphon. Occurrence. — I have met with this form in 2 different localities on the west coast of Norway, viz., at Kalvaag and Aalesund. In the latter place it occurred not unfrequently at a depth of about 10 fathoms among algse and other marine growths. Distributmi. — British Isles (Brady), coast of France (Canu), Mediter- ranean (Claus, Giesbrecht). Fam. 6. Myzopontiidae. Characters. — General form of body resembling that in some of the Asco- myzontidw, being comparatively slender, with the anterior division moderately broad, and the cephalic segment scarcely projecting at the postero-lateral cor- ners. Tail rather produced and of quite normal appearance, being composed in female of 4, in male of 5 segments. Anterior antennse slender, with the number of joints somewhat reduced; terminal part not defined, the usual sesthetask issuing from the last joint, near the tip. Posterior antennse comparatively small, but with the terminal joint more developed than in the Ascomyzontidce, outer ramus rudimentary. Oral cone more or less produced. Mandibles without any palp. Maxillae and maxillipeds on the whole normal. Natatory legs resembling in structure those in the Ascomyzontidw. Last pair of legs with the proximal joint imperfectly defined from the segment, distal joint very small or of moderate size. JRemarJcs. — This is another family, which I have found it necessary to establish in order to include the 2 genera Myzopontms and NeojmJitiiis, the systematic position of which has appeared rather doubtful. Giesbrecht refers both these genera to his sub-family Dysjjontiince, apparently on account of the somewhat similar structure of the anterior antennse; but in other respects they differ very conspicuously from the true Dysiwntiin(B, both as regards the outward appearance of the body and the structural details, while on the other hand they exhibit, several 113 characters in common, as indicated in the above diagnosis. As the genus Myzffpont'ms was the first established of the two, the name of the family must be derived from that genus. Gen. 26. MyzOpOntlUS, Giesbrecht, 1895. Generic Characters. — Anterior division of body moderately dilated, with the cephalic segment comparatively large, and the epimeral parts of the trunk- segments only slightly angular. Tail slender, though not much elongated. Caudal rami moderately produced. Anterior antennae slender and only sparingly seti- ferous; those in male distinctly hinged, and provided with supplementary sesthe- tasks. Posterior antennse likewise comparatively slender, with the penultimate joint well defined and the terminal joint rather elongated. Oral cone produced into a slender siphonal tube. Mandibles very narrow. Maxillae with the inner lobe shorter than the outer, and provided with only a single apical seta. Both pairs of maxillipeds very slender. Terminal joint of outer ramus in 1st pair of natatory legs with 3 setae inside; same joint in the 3 succeeding pairs with 5 setae. Last pair of legs very small. RemarTcs. — This genus was established in the year 1895 by Giesbrecht, to include a species found by him in the Bay of Naples. In the elaborate monograph of the Asterocheridce by the same author, this genus was placed at the head of the sub-family Dyspontiinw, and its differences from the more typical genera, showing an approach to the Asteroche7"ince (= Ascomyzontidce), were pointed out. The genus as yet only comprises a single species, to be described below. 64. Myzopontius pungens, Giesbr. (PI. LXVIII). Myzopontius puvgens, Giesbrecht, Asterocheridse, p. 106, PI. 1, fig. 6, PI. (i, lags. 1—14. Specific Characters.— Female. Body moderately slender, with the anterior division oblong oval in outline, greatest width slightly exceeding half the length. Cephalic segment very large, occupying almost half the length of the body, frontal edge evenly curved, pleural parts incurved and rather broad; rostral projection extremely small. The 3 succeeding segments gradually diminishing in size and having the epimeral parts slightly angular behind. Tail scarcely attaining half 15 — Ci'ustacea. 114 the length of the anterior division and narrow cylindrical in form; genital segment of moderate size, with the anterior part slightly dilated, forming on each side a rounded prominence. Caudal rami slightly exceeding in length the anal segment and sublinear in form, being scarcely at all divergent; outermost seta, together with the dorsal bristle, slightly remote from the apex; middle apical seta of moderate length. Anterior antenna3 slender, though scarcely exceeding half the length of the cephalic segment, and composed^ of 12 joints, the last one much the longest. Posterior antennae rather narrow, with the terminal joint consider- ably produced, being almost as long as the 2nd (basal) joint, and carrying 3 apical and one lateral seta, middle apical seta much longer than the other 2, lateral seta attached near the base. Siphon extending about to the end of the cephalic segment. Maxillae with the outer lobe rather narrow, sublinear in form, and carrying on the tip 2 moderately long seta;; inner lobe conical in form with the apical seta very slender. Anterior maxillipeds with the dactylus exceedingly narrow and elongated, distal part evenly curved and clothed inside with minute spinules. Posterior maxillipeds with the hand unusually narrow, dactylus normal. Natatory legs moderately strong, with the spines of the outer ramus finely denticulate; 1st joint of inner ramus in 1st pair unusually broad and, like the 2nd basal joint, provided on the lower face with a rounded, boss-like prominence. Last pair of legs extremely minute; distal joint provided with 3 small bristles, one apical and 2 lateral. Body, according to Giesbrecht, nearly colourless, with reddish orange translucent intestine and lateral coeca; eye very large and bright red. Length of adult female about 1 mm. Remarks. — This Copepod resembles in its outwai-d appearance certain forms of the Ascomyzontidoe, but is easily distinguishable by the rather different structure of the anterior antennae. The specific name proposed by Giesbrecht alludes to the narrowly-produced siphon, which in some cases is seen projecting from the body at nearly a right angle, as indicated in the side-view figure given by Giesbrecht. Occurrence.— A solitary, but well preserved female specimen of this form was found in a sample taken at Korshavn, south coast of Norway, from a depth of about 40 fathoms, muddy sand. Distribution. — Bay of Naples (Giesbrecht), Franz Joseph Land (Scott). 115 Gen. 27. NeOpOntlUS, Scott, 1898. Generic Characters. — Anterior division of body only slightly dilated, with some of the segments angularly produced laterally. Cephalic segment of moderate size and narrowed in front; rostral projection well marked. Tail very slender, with the genital segment in female long and narrow. Caudal rami rather pro- duced and somewhat lamellar; apical setae comparatively short. Anterior antenna) of moderate size and densely clothed with slender, curved setse; those in male imperfectly hinged and without any supplementary a^sthetasks. Posterior antennae rather stout, with the 2 middle joints imperfectly defined in female, terminal joint not much produced. Oral cone comparatively short, not being produced into a siphonal tube. Mandibles less slender than in Myzopontms, and distinctly denti- culated at the tip. Maxillse with the inner lobe larger than the outer, and car- rying at the tip 4 seta^. Maxillipeds comparatively strongly built, dactylus of the anterior ones armed inside, at some distance from the end, with a very con- spicuous curved secondary spine. Natatory legs of a similar structure to that in Myzopontius. Last pair of legs, however, more fully developed, with the distal joint rather produced and somewhat spatulate in form. Remarlcs — This is a very distinct genus, exhibiting, as it does, several well-marked differences from Myzoi^ontiiis. Yet its affinity to that genus is evidently closer than to any other of the siphonostomous Cyclopoida, and this has also been recognised both by Scott and Giesbrecht. 65. Neopontius angularis, Scott. (PI LXIX). Neopontius angularis, Scott, Sixteenth Annual Report of the Fishery Board for Scotland, Part III, p. 271, PI. XIV, figs. 1-11. Sjiecific Characters. — Female. Body very slender, with the anterior division oblong oval in outline and somewhat abruptly truncated behind. Cephalic segment scarcely occupying more than Vs of the total length and narrowly rounded in front; rostral projection well marked, but incurved, and acute at the tip. The succeeding trunk-segments rather dissimilar both in size and form, the anterior one being comparatively simple, whereas the 3rd segment is unusually broad, with the epimeral parts prominent and triangularly pointed behind; penultimate seg- ment much smaller, with the epimeral parts angularly rounded; last segment very narrow. Tail almost attaining the length of the anterior division and rather narrow; genital segment longer than the 3 succeeding segments combined, and 116 widening slightly in front. Caudal rami exceeding in length the last 2 segments combined and conspicuously lamellar, inner edge finely ciliated, outer edge exhi- biting, somewhat beyond the middle, a distinct ledge to which the outermost seta, together with the dorsal bristle, is attached ; apical setae comparatively short, but rather coarse and densely plumose. Anterior antennae somewhat exceeding half the length of the cephalic segment, and composed of 12 joints, the 2nd of which is rather large, being fully as long as the 4 succeeding joints combined ; terminal joint elongated, club-shaped. Posterior antennae comparatively short, but rather stout, with the 2 middle joints confluent; terminal joint not much prolonged, and carrying 4 elongated and finely ciliated seta3, 3 apical and one lateral. Oral cone extending only slightly beyond the insertion of the posterior maxillipeds, and evenly tapered distally. Mandibles apparently biarticulate, and very finely denticulate at the tip. Maxillae with the outer lobe scarcely more than half as long as the inner, and carrying on the tip 2 moderately long setae. Anterior maxillipeds with the distal part of the dactylus, as also the secondary spine, finely denticulate inside. Posterior maxillipeds with the hand imperfectly defined from the basal part; terminal part of the dactylus denticulate. Natatory legs moderately strong, with the spines of the outer ramus dagger- like. Last pair of legs with the distal joint well developed, sub-spatulate in form, and provided with 3 setae, 2 issuing from the transversely truncated end, the 3rd from the lower face at some distance from the apex; outer edge of the joint minutely ciliated, inner projecting near the end to a dentiform process. Male, as usual, smaller than female, and having the anterior division of the body less angular in shape. Anterior antennae more strongly built, and composed of 14 joints, those of the distal part conspicuously thickened, 10th joint armed in front with 2 slender spines, apical joint small, rounded. Posterior antennae with the 2 middle joints well defined; the posterior maxillipeds also quite normally developed. Colour (in female) yellowish grey, with scattered pigmentary patches of an ochraceous hue on the dorsal face of the anterior division of the body. Length of adult female I 35 mm., of male 1.10 mm. RemarJcs. — This is the only as yet known species of the genus, and may easily be recognized by the peculiar angular shape of the anterior division of the body, which, especially in the female, is very conspicuous and indeed has given rise to the specific name proposed by Scott. Occurrence. — I have long been acquainted with this peculiar form, of which some few specimens were collected, many years ago, at Eggesb0n8es, west coast of Norway, from a depth of about 20 fathoms. I have, however, not met with it in other localities, and it thus seems to be of very rare occurrence. Distribution. — Scottish coast (Scott). Fam. 7. Dyspontiidae. Characters. — General form of body, as a rule, very broad and depressed, with the anterior division much expanded. Cephalic segment large and arcuate in front, with the postero-lateral corners produced, and the pleural parts very broad, leaving in front only a narrow space for the insertion of the antennae and oral parts. Epimeral parts of the trunk-segments forming well-defined lappets projecting laterally. Last segment, however, as usual, not expanded and very small. Tail comparatively short, and composed in female of 4, in male of 5 segments; genital segment much expanded in its anterior part. Anterior antennae slender and narrow, with the number of joints more or less reduced, last joint club-shaped and carrying near the end the usual aesthetask; those in male more or less distinctly hinged and provided with supplementary aesthetasks. Posterior antennae very small, 4-articulate, outer ramus rudimentary. Oral cone generally much produced. Mandibles without any palp, masticatory part slender styliform, extending to the end of the siphon. Maxillae with both lobes very narrow, the inner one the larger and generally provided with only a single apical seta, outer lobe with 2 such setae. Both pairs of maxillipeds very fully developed. Natatory legs more or less incurved, with the rami compara- tively slender, the inner one in 4th pair more or less reduced, in some cases wholly wanting. Last pair of legs extremely small and rudimentary, being only represented by a minute knob-like joint accompanied outside by the usual seta. BemarJcs. — The present family does not quite answer to the sub-family Dyspontiince of Giesbrecht, in which the 2 preceding genera are also included, as also 2 other genera which I have felt justified in removing, viz., the genera Artotrogus and Dystrogus. In the restriction thus adopted, the family Dyspon- tiidae forms a very natural group, comprising a number of genera, which agree pretty well in the more essential characters. In addition to the 5 genera treated of in the following pages, the 2 genera Pteropontius and Sestropontius, estab- lished by Giesbrecht, belong to the present family, which thus at present comprises no less than 7 different genera. m Gen. 28. DySpOntiUS, Thorell, 1859. Syn: Gallopontius, Giesbrecht. Generic Characters.— Anterior division of body broad and expanded, with the epimeral lappets well marked; those of penultimate segment, however, very small. Tail short, with the genital segment considerably expanded. Anterior antennae in female generally 9-articulate, with the 2nd joint the largest. Siphon rather strong, with the basal part only slightly dilated. Maxillae with the lobes not very unequal, the inner one carrying a single apical seta, the outer one 2 such setae. Maxillipeds moderately slender. Natatory legs with the rami comparatively narrow, terminal joint of outer ramus in 1st pair small, with only 2 spines out- side and 2 setae inside. 4th pair of legs with the outer ramus well developed, inner however wholly absent. Free joint of last pair of legs with only 2 apical bristles. BemarJcs. — This genus, the type of the present family, was established in the year 1859 by Thorell, who placed it together with the genus Ascomyzon within his family Ascomyzontidm. The genus Gallopontius, at first established by Giesbrecht for a Neapolitan species, G. fringilla, was subsequently withdrawn by that author and identified with Thorell's genus. In addition to the above-' named species another Neapolitan species was described as D. passer. The chief characters of the present genus are found in the form of the siphon, the armature of the terminal joint of the outer ramus in the 1st pair of legs, and the total absence of an inner ramus in the 4th pair. In the last-named character it however agrees with 2 other genera, viz., Crypiopontius and Ptero- pontius. To the fauna of Norway belongs only the type species, to be de- scribed below. 66. Dyspontius striatus, Thorell. (PL LXX). Dyspontius striatus, Thorell, Bidrag til kamiedomen om Crustaceer, sora lefva i arter af slfegtet Ascidia, p. 81, PI. XIV, fig. 22. Syn: Gallopontius rotundus, Giesbrecht. Specific Characters. — Female. Body pronouncedly depressed, with the anterior division broad and expanded, greatest width almost equalling the length. Cephalic segment very large, occupying rather more than half the total length, postero-lateral corners prominent, frontal part evenly rounded, without any dorsal crest; pleural parts of the segment longitudinally striated. Epimeral lappets of the 2 succeeding segments well developed, those of penultimate segment, however, 119 very small. Tail scarcely exceeding in length Vs of the anterior division; anterior part of genital segment considerably expanded. Caudal rami comparatively short, being only slightly longer than they are broad, outermost seta somewhat remote from the apex, inner mediate one a little longer than the tail. Anterior antennae about half the length of the cephalic segment, and composed of 9 joints, 2nd joint the longest; terminal joint somewhat exceeding in length the 2 preceding joints combined. Posterior antennse with the terminal joint about as long as the preceding one; middle apical seta rather slender, the other 2 short. Siphon comparatively strong and gradually tapered distally, extending somewhat beyond the limits of the cephalic segment. Maxillae with the inner lobe only slightly longer than the outer and rather narrow, apical seta scarcely as long as the lobe; apical setae of outer lobe rather slender. Anterior maxillipeds with the dactylus very slender and elongated, terminating in a short, slightly curved claw, and armed at some distance from this claw with a small secondary spine. Posterior maxillipeds normal. Natatory legs with the spines of the outer ramus comparatively short, 2nd basal joint in 2nd— 4th pairs angularly produced inside; 4th pair with the outer ramus fully as large as in the 2 preceding pairs and armed in a similar manner; of an inner ramus not the slightest rudiment present. Ovisacs globular in form. Male considerably smaller than female, and having the anterior division of the body less broad. Genital segment greatly swollen, to receive the 2 globular spermatophores. Anterior antennae composed of 11 joints, and distinctly hinged, the last 2 joints forming together a movable part, which admits of being bent upon the adjoining part of the antenna; 8th joint somewhat dilated, and armed in the middle of the anterior edge with a short spine. Colour of female generally pale yellowish grey, with a few small reddish spots on the cephalic segment; intestine and its distinctly lobular coeca of a darker yellow hue. Length of adult female amounting to 1.45 mm., of male to 1.10 mm. Remarhs. — This form was described by Thorell from a solitary female specimen taken by Lilljeborg in the open sea, and was supposed by that author to be, like Ascomyzon Lilljeborgi, an internal parasite of Ascidise. It has sub- sequently been recorded in both sexes by several other authors, though in some cases it appears somewhat doubtful, whether the descriptions in reality refer to the present species or to some other nearly-allied form. The form at first recorded by Giesbrecht from the Bay of Naples as Gallopontius rotmuhis has subsequently been identified by that author with the present species. From the 1^0 other 2 Neapolitan species, D fringilla and D. passer, it is at once distinguished by the different form of the cephalic segment and the absence of any frontal crest. Occurrence. — I have met with this characteristic form in many places of the Norwegian coast, from the Christiania Fjord up to Finmark (Hammerfest). AH the specimens have been taicen free in the sea among algse and other marine growths, and there is indeed little probability that this form ever, as supposed by Thorell, has its abode within the branchial cavity of Ascidise. Distribution.— ChvhimQhQxg (Thorell), British Isles (Brady), coast of France (Canu), Bay of Naples (Giesbrecht). I Gen. 29. CryptOpOntlUS, Giesbr., 1899. Generic Characters. — Anterior division of body less expanded and less depressed than in Dyspontius, with the epimeral lappets more densely crowded and curved backwards; those of penultimate segment very small, almost wholly concealed. Tail short, but with unusually long apical setse. Structure of the 2 pairs of antennae about as in Dysyontius. Oral cone with the basal part con- spicuously thickened and terminating in a very slender siphonal tube. Maxillse with the lobes rather unequal in length and very narrow; apical setse on both lobes slender. Anterior maxillipeds with the dactylus exceedingly slender and elongated. Posterior maxillipeds normal. Natatory legs with the rami compara- tively less slender than in Dyspontius ; outer ramus of 1st pair without any seta inside the 1st joint, terminal joint well developed, with 3 spines outside and 3 setse inside. 4th pair of legs without any inner ramus. Last pair of legs exhibiting a rudimentary structure similar to that in Dyspontius. Remarks. — The above generic diagnosis chiefly refers to the species described below, as I am by no means certain that the other 3 species referred by Giesbrecht to this genus are in reality congeneric. The chief dif- ferences from Dysjwntius are found in the general form of the body, the struc- ture of the siphon, and the armature of the outer ramus of the 1st pair of legs. 67. Cryptopontius brevifureatus, Giesbr. (PI. LXXI). Cryptopontius hrevifurcatns, Giesbrecht, Asterocheridse, p. 109, PI. 1, fig. 7, PI. 8, figs. 1 — 12. Specific Characters. — Female. Body less expanded than in most other Dyspontiidce, with the anterior division oblong oval in outline, greatest width only slightly exceeding half the length. Cephalic segment very large, nearly twice as long as the remainder of the body, and narrowly rounded in front, with no crista dorsally; rostral prominence very small. Epimeral lappets of the 2 succeeding segments rather broad and curved backwards; those of penultimate segment extremely small and conical in form, being almost wholly concealed in the dorsal view of the animal. Tail scarcely exceeding in length V* of the {interior division, genital segment much dilated in its anterior part. Caudal rami very short, being scarcely longer than they are broad, and transversely truncated at the end, outermost seta attached close to the apex and much shorter than the innermost one; inner mediate seta twice as long as the outer, and attaining about half the length of the body. Anterior antennae of moderate length and composed of 9 joints, the elongate 2nd joint however exhibiting at the base and at the end slight traces of a subdivision; terminal joint somewhat longer than the 2 preceding ones combined. Posterior antennse with the hist '' joints of about equal size ; middle apical seta rather slender and flexuous. Siphon extremely slender, extending almost to the end of the anterior division of the body. Maxillae with the outer lobe scarcely more than half as long as the inner and having the 2 apical setae rather unequal in length; apical seta of inner lobe very slender. Anterior maxillipeds with the dactylus much elongated and narrow, secondary spine of moderate size and attached at a short distance from the apical claw. Posterior maxillipeds with the hand densely ciliated outside. 1st pair of legs considerably smaller than the 2 succeeding pairs, but having the terminal joint of the outer ramus well developed; 2nd and 3rd pairs rather strongly built, with the 2nd basal joint lamellarly produced inside; 4th pair with the outer ramus smaller than that of the 2 preceding pairs, but otherwise of a very similar structure, inner ramus wholly absent. Last pair of legs about as in Dyspontius striatus. Male, as usual, smaller than female, and having the anterior division somewhat more depressed. Anterior antennae composed of only 10 joints, no apical joint being cut off; 8th joint somewhat dilated and exhibiting near the end in front a short dentiform projection. Body in female of a whitish grey colour, with a faint yellow tinge. Length of adult female 0.90 mm., of male 0.75 mm. RemarTcs. — I cannot doubt that the above-described form is identical with Giesbrecht's species, though there are some few points of discrepancy. It is an easily recognizable species, differing conspicuously from the other Dyspontndce in the general form of the body, especially as regards the female. 16 — Crustacea. Occurrence. — The only place, where I have met with this form, is at Korshavn, south coast of Norway. It occurred here occasionally on a sandy bottom, at a depth of about 40 fathoms. Distribution. — Bay of Naples (Griesbrecht). Gen. 30. ArCtOpOIltiUS, G. O. Sars, n. Generic Characters.— Anterior division of body greatly expanded, with the cephalic segment exceedingly large and prominent at the postero-lateral cor- ners; epimeral lappets of the 3 succeeding segments well developed and produced laterally. Tail comparatively short, with the genital segment unusually broad, being expanded on each side in a somewhat similar manner to that in the trunk- segments. Anterior antennae comparatively short, 8-articulate (in female). Posterior antenna) very small, but of the usual structure; Siphon resembling in structure that in Dyspontius, but less produced. Maxillae with the lobes rather unequal in size. Both pairs of maxillipeds, but especially the anterior ones, very strongly built. 1st pair of natatory legs with the terminal joint of the outer ramus carrying inside 3 setae and outside only 2 spines; 4th pair with the outer ramus normally developed, inner very small, biarticulate. Last pair of legs still more rudimentary than in the 2 preceding genera. RemarJcs. — This new genus differs from the 2 preceding ones in the very broad and flattened form of the body, the comparatively short antennae, the very powerfully developed maxillipeds, and, finally in the presence on the 4th pair of legs of a distinct, though rather imperfectly developed inner ramus. It com- prises as yet only a single species, to be described below. 68. Aretopontius expansus, G. 0. Sars, n. sp. (PI. LXXII). Specific Characters. — Female. Body very broad and pronouncedly depressed, with the anterior division almost as broad as it is long. Cephalic segment occu- pying more than half the total length, postero-lateral corners considerably pro- jecting, free edges evenly curved, front narrowly rounded, without any dorsal crest; rostrum of the usual short linguiform-shape. Epimeral lappets of the 3 succeeding segments rather produced; those of penultimate segment resembling in shape the preceding ones, though somewhat smaller. Tail scarcely exceeding 1^3 in length Vs of the anterior division; genital segment remarkably dilated in its anterior part, forming on each side a large wing-like expansion somewhat similar in shape to the epimeral lappets of the trunk- segments. Caudal rami short, being scarcely longer than they are broad ; outermost seta at some distance from the apex and about the length of the innermost, the 2 median setae not much prolonged. Anterior antennae not nearly attaining half the length of the cephalic segment, and composed of only 8 joints, the 2nd much the longest, terminal joint scarcely longer than the 2 preceding joints combined. Posterior antennae very small, with the terminal joint somewhat longer than the penultimate one, middle apical seta not much prolonged. Siphon rather coarse, extending about midway between the insertion of the posterior maxillipeds and that of 1st pair of legs. Maxillae with the inner lobe almost twice as long as the outer and narrowly exserted distally, apical seta comparatively short, those of the outer lobe subequal in length. Anterior maxillipeds remarkably powerful, with the dactylus exceedingly strong and hamiformly curved at the tip, secondary spine very small. Posterior maxil- lipeds likewise rather strongly built, and having the terminal claw of the dactylus densely clothed with small denticles. 1st pair of legs, as usual, somewhat smaller than the 2 succeeding ones, which are rather strongly built, with the 2nd basal joint triangularly produced inside. 4th pair of legs with the outer ramus normal, inner ramus, however, very imperfectly developed, forming a small incurved stem composed of only 2 subequal joints, each carrying a single short seta. Free joint of last pair of leg extremely minute and apparently only provided with a single small bristle Colour not yet ascertained. Length of adult female about 2 mm. Male unknown. BemarJcs. — This form may be readily recognised from the other members of the present family by its very broad depressed body, and the greatly expanded genital segment. Only the female sex is as yet known. Occurrence. — Only 2 female specimens of this form have hitherto come under my notice. They were taken, many years ago, at Hammerfest, western Finmark, from a depth of about 20 fathoms. 124 Gen. 31. BradypOntiUS, Giesbr., 1895. Syn: Artotrogus, Brady (part). Generic Characters. — Anterior division of body more or less expanded, with the cephalic segment large and considerably produced at the postero-lateral corners; epimeral lappets of the trunk-segments well defined and successively diminishing in size behind. Tail somewhat more produced than in the 3 pre- ceding genera, with the genital segment moderately dilated. Anterior antennse more or less slender, and composed of a somewhat varying number of joints in the different species. Posterior antennae of the usual structure. Siphon comparatively slender, with the basal part somewhat thickened. Maxillsc with the lobes more or less unequal. Maxillipeds comparatively slender. Natatory legs rather strongly built; terminal joint of outer ramus in 1st pair with 3 spines outside and 3 setse inside; 4th pair with the inner ramus distinctly 3-articulate, though in most cases rather feebly developed, with some of the setae reduced. Last pair of legs some- what less rudimentary than in the preceding genera, the free joint being provided with 3 bristles, 2 apical and one lateral. RemarTcs. — The chief character by which this genus is distinguished, as compared with the 3 preceding ones, is the presence on the 4th pair of legs of a distinctly 3-articulate inner ramus, which however in most cases is rather feebly developed. Otherwise it exhibits on the whole a rather close relationship to the typical genus Dysponiiiis. 4 species referable to the present genus will be described below, and a 5th species has been recorded by Giesbrecht from the Bay of Naples under the name of B. siphonatus. 69. Bradypontius magnieeps (Brady). (PI. LXXIII). Artofrogns magnieeps, Brady, Monograph of British Copepoda, Vol. Ill, p. 61, PI. XCIII, figs. 1—9. Syn: Artotrogus orbicularis, Brady & Eoherts. (not Boeck). „ ? — Normanni, Cami (not Brady). „ ? Bradypontius Canui, Gieshrecht. Specific Characters. — Female. General form of body somewhat similar to that in Dyspontius striatus, the anterior division being rather expanded, with the greatest width almost equalling the length. Cephalic segment very large, occupying about half the total length, and having the free edges evenly arched, postero- lateral corners rather produced, frontal part rounded, without any dorsal crest. Epimeral lappets of the 3 succeeding segments well defined and pointing obliquely backwards; those of penultimate segment of same shape as the preceding ones, though I 125 somewhat smaller. Tail not attaining half the length of the anterior division; genital segment moderately dilated in its anterior part; anal segment exceeding in length the 2 preceding ones combined. Caudal rami rather produced, being more than twice as long as they are broad, and fully attaining the length of the anal segment; outermost seta not far from the apex and somewhat shorter than the innermost; the 2 middle setae of moderate length. Anterior antennae about half the length of the cephalic segment, and composed of 8 (or 9) joints, the 2nd being much the largest; terminal joint almost the length of the 2 preceding ones combined. Posterior antennae with the terminal joint longer than the penultimate one, middle apical seta of moderate length, the other 2 very small. Siphon rather slender, extending beyond the limits of the cephalic* segment. Mandibles narrow styliform, and distinctly denticulated at the apex. Maxillae with the lobes com- paratively narrow and somewhat unequal in length, apical seta of the inner one quite short, those of the outer slender and subequal. Maxillipeds well developed, dactylus of the anterior ones moderately slender, with a small secondary spine at some distance from the end; terminal claw comparatively short. 1st pair of natatory legs not much smaller than the 2 succeeding ones, seta at the inner corner of the 1st basal joint conspicuously thickened. 4th pair of legs with the inner ramus much narrower than the outer and only slightly exceeding in length the 2 first joints of this ramus combined, setae present in the usual number, but rather reduced in size. Free joint of last pair of legs small, and as in the other species provided with 3 bristles, the innermost one the longest. Ovisacs rather large and globular in form. Colour not yet ascertained. Length of adult female 1.80 mm. Male unknown. RemarJcs. — I think I am right in identifying the above-described fomi with Brady's species, as it agrees fairly well in its outward appearance with the figure given by that author. The apparent differences found in some of the structural details may indeed be due to a less careful examination by the said author. It appears to me somewhat more doubtful, if the form described by Canu as Arto- trogus Noi'mani, and subsequently named by Giesbrecht Bradypontius Ccmui, is in reality identical witli the present species, as set forth by the last-named author in his Monograph of the Asterocheridce ; and the form briefly described and figured by Giesbrecht in the same Monograph as B. magnicejjs, also seems to differ in some respects. The present species was at first erroneously identified by Brady and Robertson with Artotrogus orbicularis Boeck; and though this mistake was sub- 126 sequently corrected, it was still referred by Brady in his Monograph to Boeck's genus, which in reality is so very different, that in my opinion it cannot even be included in the present family. Occurrence.— Only a few female specimens of this form have hitherto come under my notice. They were taken free in the sea in two widely-distant localities, viz., at Aalesund, west coast of Norway, and at Hammerfest, western Finmark. Distribution.— British Isles (Brady), ? coast of France (Canu). 70. Bradypontius papillatus (Scott). (PI. LXXIV). Artotrogus painllatus, Scott, Sixth Annual Report of the Fishery Board for Scotland, Appendix, p. 232, PL VIII, figs. 7-12. Syn: Bradypontius chelifer, Giesbr. Specific Characters. — Female. Anterior division of body rather broad in its posterior part, greatest width however not quite equalling the length. Cephalic segment very large, occupying more than half the total length, and gradually contracted anteriorly, postero-lateral corners very prominent, frontal part nar- rowly produced, with a very distinct crest running along its dorsal face; rostral projection well marked, incurved. Epimeral lappets of the 2 succeeding segments well developed and considerably divergent; those of penultimate segment, however, rather small and conically pointed. Tail only slightly exceeding in length Vs of the anterior division; genital segment moderately dilated in front; anal segment not attaining the length of the 2 preceding ones combined. Caudal rami about twice as long as they are broad, and equal in length to the anal segment; outer- most seta at some distance from the apex, and shorter than the innermost; the 2 middle setse of moderate size. Anterior antennae about half the length of the cephalic segment, and composed of 9 joints, 2nd joint the largest, terminal joint exceeding in length the 2 preceding joints combined. Posterior antennae resembling in structure those in B. magnice2)S, except that the outermost apical seta is com- paratively longer. Siphon scarcely extending beyond the inseition of the 1st pair of legs. Maxillae with the lobes less slender than in B. magnicejjs, apical seta of the inner one short, those of outer lobe very coarse, spiniform, and finely denti- culated. Anterior maxillipeds with the dactylus rather strong and provided at some distance from the end with 2 small thumb-like prominences, against which the curved terminal claw may admit of being impinged; secondary spine very small and placed outside the said prominences. Posterior maxillipeds normal. Natatory legs resembling in structi^re those in B. magnicejps, except that the inner 127 ramus in 4tli pair is much smaller, scarcely attaining the length of the 2 first joints of the outer one combined, and very narrow, with some of the setae aborted. Last pair of legs about as in the preceding species. Colour dark yellow or orange. Length of adult female amounting to 1.60 mm. Remarlcs.—l cannot doubt that the above-described form is that originally recorded by Scott as Artotrogus iminllatus, and that Giesbrecht's Bradijjjontius chelifer is the same species. It is true, that the number of joints in the anterior antennae is indicated by both these authors to be only 8, and that the terminal part of the dactylus in the anterior maxillipeds is represented much shorter and thicker than in the specimen examined by me; but these apparent differences are in all probability due to the circumstance that the specimens examined by those authors had not arrived at full maturity, as proved by their much inferior size (1.15 — 1.20 mm.). In all other respects the agreement seems to be perfect. From the type species, B. magniceps, the present one is easily distinguished by the rather different form of the cephalic segment and of the epimeral lappets, as also by the comparatively shorter caudal rami. The very feeble development of the inner ramus on the 4th pair of legs forms another rather characteristic specific mark. Occurrence.— Some few female specimens of this form were collected, many years ago, in 2 localities on the west coast of Norway, viz., at Aalesund and Eggesbonses. The specimens were taken free in the sea, at depths ranging from 20 to 40 fathoms. Distribution. — British Isles (Scott), Bay of Naples (Giesbrecht). 71. Bradypontius major, G. 0. Sars, n. sp. (PL LXXV). Specific Characters. — Female. General form of body somewhat similar to that in B. impillattis, the cephalic segment being very large and gradually con- tracted anteriorly, with a well-marked dorsal crest running along its frontal part. Epimeral lappets of the 3 succeeding segments more closely crowded together and less unequal than in the said species; those of penultimate segment well developed, though somewhat narrower than the others. Tail comparatively short, only slightly exceeding in length Vs of the anterior division; genital segment considerably dilated in its anterior part; anal segment equalling in length the 2 preceding ones combined. Caudal rami scarcely twice as long as they are broad, and shorter than the anal segment, apical setae about as in the preceding species. Anterior antennae not very elongated, but composed (in the specimen examined) of no less 128 than 13 well-defined joints, a short joint being divided off from the elongated 2nd joint both at the base and at the end, and moreover each of the 2 joints pre- ceding the terminal one being distinctly subdivided; terminal joint about the length of these 4 joints combined. Posterior antennae a little more slender than in B. papillatiis, but otherwise of a very similar structure. Siphon rather produced, extending considerably beyond the limits of the cephalic segment. Mandibles very slender and distinctly denticulated at the tip. Maxillae with the lobes narrow and rather unequal in length; apical seta of the inner one much produced, those of the outer rather slender. Anterior maxillipeds with the dactylus much more slender than in B. papillatus, with only a single small thumb-like process rather far from the apex, secondary spine well marked. Natatory legs with the rami comparatively less slender than in that species; inner ramus of 4th pair more fully developed, exceeding in length the first 2 joints of the outer one combined. Free joint of last pair of legs a little larger than in B. papillatus. Male considerably smaller than female, and having the anterior division less expanded. Anterior antennae, as in female, composed of 13 joints, 6th and 7th joints very short and less sharply defined, 10th joint conspicuously dilated and armed anteriorly with 2 slender spines, movable terminal part distinctly biarticulate. Inner ramus of 4th pair of legs comparatively longer than in female, terminal joint produced at the outer distal corner to an outward-curving denti- form projection, outer apical seta, as also that of the outer edge replaced by a short club like spine. Body in female of a dark yellowish grey colour, and ornamented on the dorsal face with a reddish branching pigment. Length of adult female amounting to 2.40 mm., of male to 1.95 mm. Remarks. — This form is closely allied to B. papillatus, but of much larger size, and moreover differs conspicuously in the shape of the epimeral lappets of the trunk-segments, as also in some of the structural details, as indicated in the above diagnosis. Occurrence. — Solitary specimens of this large species have been taken at Aalesund, west coast of Norway, and in the Trondhjem B^jord, at Rodbjerget, in both localities from considerable depths. 72. Brady pontius eaudatus, G. 0. Sars, n. sp. (PI. LXXVI). Specific Character's. — Female. Body comparatively more slender than in the other species, with the anterior division moderately expanded. Cephalic 129 segment large, though scarcely occupying half the total length, and only slightly contracted anteriorly, frontal crest only faintly indicated, postero-lateral corners of the segment fairly prominent. Epimeral lappets of the 3 succeeding seg- ments moderately produced; those of penultimate segment rather smaller than the preceding ones. Tail comparatively more produced than in the other species, attaining nearly half the length of the anterior division; genital segment not much expanded in its anterior part; anal segment scarcely as long as the 2 preceding ones combined. Caudal rami about twice as long as they are broad, and slightly dilated in the middle; outermost seta rather far from the apex and much shorter than the innermost, the 2 middle setae of moderate length. Anterior antenn£E unusually slender and elongated, considerably exceeding half the length of the cephalic segment, and composed of 12 well-defined joints, the last of which is the longest. Posterior antennae likewise rather slender, with the ter- minal joint nearly tw^ice as long as the penultimate one. Siphon moderately produced, extending about to the insertion of the 1st pair of legs. Maxillae with the lobes not very unequal; apical seta of the inner one quite short, those of the outer very coarse, spiniform and densely spinulose. Maxillipeds resembling in structure those in B. major, the dactylus of the anterior ones being very slender, with only a single small thumb-like process at some distance from the end, terminal claw much curved, secondary spine small. Natatory legs rather strongly built, with the exterior edge of the outer ramus coarsely serrate; inner ramus of 4th pair not much shorter than the outer, but rather narrower. Free joint of last pair of legs somewhat more produced than in the other species. Colour reddish brown. Length of adult female reaching to 2.90 mm. Male unknown.^) Remarks. — This form grows to a still larger size than B. major, and is indeed the largest of all the siphonostomous Cyclopoida with which I am acquainted. It moreover exhibits several well-marked differences from the other species, both as to its outward appearance and the structural details. The specific name alludes to the unusually produced tail. Occurrence. — 2 female specimens only of this form have come under my notice. They were taken, many years ago, at Tj0t0 on the Nordland coast, from the considerable depth of 150 fathoms 1) It may be, however, that the male specimen mentioned above as belonging to B. major, should more properly be referred to the present species, though it was found in company with the former. Indeed, on a closer examination, I have found that the caudal rami in that specimen, as also the mutual relations of the joints in the inner ramus of the 4th pair of legs, agree better with the present species. 17 — Crustacea. ' 130 Gen. 32. CribrOpOlltiUS, Giesbr. 1899. Syn: Artotrogns, Brady (part). Generic Characters.— Body robust, with strongly chitinised integuments, and with some of the epimeral lappets very prominent. Tail somewhat pro- duced and having the genital segment in female less expanded than in the other genera. Caudal rami lamellar, with comparatively short apical seta?. Anterior antennae comparatively stout and scarcely at all attenuated clistally. Posterior antennae with the terminal joint comparatively short. Siphon rather strong and not much produced. Maxijlie wiih the lobes very unequal in size and each provided with 2 slender apical setae. Both pairs of maxillipeds, but especially the posterior ones, very powerfully developed. Natatory legs on the whole agreeing in structure with those in Bradypontius ; inner ramus of 4th pair, as in that genus, distinctly 3 -articulate. Last pair of legs somewhat more fully developed than in the other Dyspontiidce. EemarJcs.— This genus, established by Giesbrecht, is allied to Brady- pontius, agreeing with it in the presence of a distinctly 3-articulate inner ramus on the 4th pair of legs. It differs however in some points rather conspicuously, both as regards the outward appearance and some of the structural details, and therefore ought evidently to be supported. We do not know at present more than a single species, to be described below. 73. Cpibropontius Normani, (Brady). (PL LXXVII). Artotrogm Normani, Brady, Monograph of British Copepoda, Vol. Ill, p. 63, PI XCI, figs. 12—15, PL XCII, fig. 14, PL XCIII, fig. 10. Syu : DysjJontius Normani, Brady & Roberts. „ BradyiJontius Normani, Giesbrecht. Specific Characters. — Female. Anterior division of body moderately expanded and somewhat depressed, with the greatest width slightly exceeding Vs of the length. Cephalic segment large, though not occupying quite half the total length, free edge evenly curved, frontal part rounded, without any dorsal crest, postero-lateral corners divided into 2 short lappets; rostral projection well defined, incurved. Epimeral lappets of the 3 succeeding segments rather unequal, those of antepenultimate trunk-segment much the largest, and greatly projecting to each side; those of penultimate segment well developed, though smaller than the 2 preceding pairs. Tail attaining nearly half the length of the anterior division; genital segment gradually somewhat dilated anteriorly; anal segment about the 131 length of the 2 preceding ones combined, and conspicuously widening distally. Caudal rami rather broad, and somewhat shorter than the anal segment, with the inner edge finely ciliated, outer edge exhibiting, at some distance from the end, a distinct ledge, to which the outermost seta and the very small accom- panying dorsal bristle are attached; apical setse comparatively short, but rather coarse and densely ciHated. Anterior antennae not nearly attaining half the length of the cephalic segment, and composed of 9 joints rather densely clothed with short, but rather coaise, curved setae, 3rd joint much the largest, terminal joint club-shaped and about the length of the 2 preceding joints combined. Posterior antennae with the terminal joint shorter than the penultimate one, apical setae spiniform, the middle one, as usual, the longest. Siphon extending about midway between the insertion of the posterior raaxillipeds and that of 1st pair of legs. Mandibles minutely denticulated at the apex. Maxillae with the outer lobe scarcely half as long as the inner, apical setae on both lobes very slender and curved. Anterior maxillipeds with the dactylus very strong and evenly curved in its distal part, terminating in a blunt point; secondary spine of moderate size. Posterior maxillipeds still more powerful than the anterior ones, with the dactylus exceedingly strongly built, its proximal joints being unusually stout, with the spines issuing inside very coarse, terminal claw occupying rather more than half the length of the dactylus. Natatory legs well developed, with the rami comparatively broad; inner ramus of 4th pair, however, considerably narrower than the outer and also somewhat shorter. Free joint of last pair of legs slightly produced, oblong quadrangular in form, and carrying at the tip one long and 2 short bristles. Ovisacs of moderate size and globular in shape. Body of a light yellowish grey colour and ornamented with a number of very conspicuous brick-red patches, 2 median, the one occupying the front part of the cephalic segment, the other the dorsal face of the 3 succeeding segments, and 3 lateral on each side, the 2 anterior pairs occurring on the cephalic segment, the posterior pair on the projecting epimeral lappets of the 3rd segment ; ova in the ovisacs of a yellowish red colour. Length of adult female amounting to 1.70 mm Remarls. — This form was at first recorded by Brady and Robertson as a species of the genus Dysjwittius, and was subsequently by the first-named author erroneously referred to the genus Artotrogus of Boeck. This mistake was corrected by Giesbrecht, who found it to agree much better with the genus Brady po7itius, to which it was indeed at first referred by that author. After having examined more closely a specimen sent to him by Scott, he felt how- ever justified in excluding it also from this genus as the type of a new nearly- 132 allied genus. The present form is indeed, easily distinguishable from any of the species of that genus, and is, moreover, in the living state at once recognised by its peculiar colour, which has also been mentioned by Scotf. Occurrence.— I have met with this handsome form occasionally in 2 or 3 places on the west coast of Norway in depths ranging from 20 to 50 fathoms. Distribution.— Briikh Isles (Brady), Madeira (Thompson). Fam. 8, Artotrogidae, Characters. — Body very broad, more or less clypeiform, with the 2 posterior trunk-segments imperfectly developed. Tail quite short, and composed in female of 4, in male of 5 segments. Antennae and oral parts on the whole built on the same type as in the Dyspordiidce. Only 3 pairs of natatory legs present, the 4th pair being wholly absent. Last pair of legs not defined from the corresponding segment. Ovisacs in female more or less concealed beneath the body. JRemarJcs. — This family, as here defined, does not answer at all to the family Artotrogidce of Brady, which, like the family Asterocheridoe of Giesbrecht, was established to include all the siphonostomous Cyclopoida. In the restriction here adopted, this family only comprises 2 genera, viz., Artolrogus Boeck and Dystrogus Giesbrecht, both of which agree in one very essential character, viz., in the total absence of the 4th pair of legs, in this respect exhibiting an approach to the next family, the Cancer Ulidm. The exact comparison of these 2 genera is rendered somewhat difficult by the circumstance that of the one (Artotrogus) we only know the female sex, of the other (Dystrogus) only the male sex. It is evident, however, that they represent two distinct generic types. Gen. 33. ArtOtrOgUS, Boeck, 1859. Oeneric Characters. ~ Body greatly expanded, rounded in form, with the epimeral lappets of the cephalic segment and the 2 anterior trunk-segments well developed, imbricate. The last 2 trunk-segments almost wholly concealed, with no epimeral lappets. Tail very short, projecting only slightly beyond the anterior 133 division; genital segment (in female) with a lamellar, posteriorly-pointing expansion on each side. Caudal rami short. Anterior antennae comparatively small and resembling in structure those in the Dyspontiidce. Posterior antennae still smaller, 4-articulate, with the outer ramus rudimentary. Siphon well developed and rather coarse, gradually tapered distally. Mandibles without any palp. Maxilla? with the lobes rather unequal in size. Both pairs of maxillipeds powerfully developed. Natatory legs strongly incurved, with the rami subequal in length, and on the whole built on the same type as in the Dyspontiidce, except that the 4th pair is wholly wanting. Remarks. — This genus was established as early as the year 1859 by Boeck, to include a peculiar Copepod found by him on the south coast of Norway. As only a solitary specimen was observed by that author, the generic characters were not made out satisfactorily, and several errors were indeed introduced, which however have partly been corrected by subsequent authors. The genus comprises as ycl only a single species, to be described below. 74. Artotrogus orbicularis, Boeck. (PI. LXXVIII). Artotrogus orbicularis, Boeck, Tvende nye parasitiske Krebsdyr; Chr. Vid. Selsk. Forliaudl. f. 1859, p. 171, PI. I, figs. 1—10. Specific Characters. — Female. Body pronouncedly clypeiform, and nearly orbicular in outline, with the dorsal face evenly vaulted, the ventral flattened or concaved. Cephalic segment very large, occupying rather more than half the total length, and having the free edges evenly arched; posterolateral corners triangularly produced and curved backwards; frontal part scarcely prominent and without any dorsal crest; rostral prominence imperfectly defined and blunted at the end. Epimeral lappets of the 2 succeeding segments large and recurved. Tail extremely short, being almost wholly received within the deep emargination formed behind between the epimeral lappets of the 2nd free trunk-segment; genital segment sub- quadrate in form, and produced on each side behind to a narrow lamella flanking the 2 succeeding very short segments; anal segment larger than those segments combined and somewhat widening distally. Caudal rami scarcely longer than they are broad, and rather wide apart, outermost seta at some distance from the end and about the length of the innermost; the 2 middle setae not much produced. Anterior antennas scarcely attaining in length Vs of the cephalic segment, and composed of 9 joints clothed with moderately long setae, 1st and 3rd joints the longest; terminal joint club-shaped and about the length of the 2 preceding ones combined; the aesthetask, attached to this 134 joint, at some distance from the end, of moderate length. Posterior antennas with the .outer ramus very small and provided with only a single minute bristle; terminal joint longer than the penultimate one and somewhat curved in its outer part, seta of outer edge attached at a short distance from the end. Siphon extending only slightly beyond the insertion of the posterior maxillipeds. Maxillae with the outer lobe scarcely half as long as the inner; apical setae of both lobes rather slender. Anterior maxillipeds with the dactylus exceedingly strong and hamiformly curved at the end; secondary spine small. Posterior maxillipeds more normally developed, terminal claw of the dactylus occupying about half its length, and finely denticulate inside. 1st pair of natatory legs somewhat smaller than the 2 succeeding ones, and having the terminal joint of outer ramus of moderate size and provided outside with 3 spines and inside with 3 setae. Inner ramus of 3rd pair differing from that of 2nd pair in the absence of the usual apical spine. Not even the slightest rudiment of a 4th pair present. Last pair of legs only represented by 3 small bristles, all issuing immediately from the sides of the corresponding segment. Lateral c^ca oi intestine very fully developed, extending along the sides of the cephalic segment and also penetrating into the adjacent part of the trunk, being divided outside into numerous narrow lobules. Ovisacs globular in form and wholly concealed beneath the posterior part of the trunk. Body of a light yellowish brown colour, with the intestine and its lateral coeca of a darker hue; ova in the ovisacs orange-coloured. Length of adult female about 2 mm. Male (at least in its adult state) unknown.') Remarlcs. — The present Copepod cannot be confounded with any of the other siphonostomous Oyclopoida, being clearly distinguished by the pronouncedly clypeiform shape of the body and its nearly circular form. It is however not improbable that the hitherto unknown female of Dystrogus will be found to approach nearer to Artotrogus in the general form of the body than does the male. Occurrence. — This peculiar form was observed by my late father at a very early period, at Manger, north of Bergen, where several specimens were taken by him from nudibranchiate Mollusca. The specimen described by Boec.k was found by him on a species of Doris taken at Farsund, south coast of Norway. I have myself met with this form in two widely distant localities of the Norwegian coast, viz., at Kleven, near Mandal, and at Hasvig, western Finmark. In both ^) It is very questionable if the specimen described by Scott as the male of the present form Avas in reality of that sex, and T think that Giesbrecht was right in believing it to be qnite an immature form, in which the sexual characters had not yet appeared. 1^6 localities the specimens were taken in the free state among algae and other marine growths. Distribution. — British Isles (Scott), Kara Sea (Hansen), Ceylon (A. Scott). Fam. 9. Cancerillidae. Characters. — Body of i-ather different shape in the different genera, but scarcely clypeiforra. The 2 or 3 posterior trunk-segments imperfectly developed, without any epimeral plates. Tail short or moderately produced, with a some- what varying number of segments. Anterior antenna) normal. Posterior antennae, however, very unlike those in the preceding families, being transformed into strong prehensile organs terminating in a powerful curved claw. Siphon imperfectly developed, in some cases obsolete. Mandibles short, mucroniform, extending straight inwards, palp absent Maxillae likewise incurved and terminating in one or 2 setiferous lobes. Maxillipeds on the whole built in the usual manner; though attached at a somewhat greater distance from the median line than in the other families. Some of the posterior pairs of legs imperfectly developed or quite wanting, this imperfect development in some cases even extending to all the legs (in female). • Remarks. — This family answers to the subfamily CanceriUiyice of Giesbrecht, and contains as yet only 2 genera, to be treated of below. These genera, it is true, differ considerably, both as to the outward appearance of the body and to some of the structural details, but yet exhibit some well-marked features in common, the most essential of which are the prehensile character of the posterior antennae, and the imperfect development of the siphon and of some of the legs. Gen. 34. ParartOtrOgUS, Scott, 1893. Generic Characters. — General form of body not deviating much from the usual type, the anterior division being moderately dilated and somewhat flattened. Cephalic segment more or less expanded in the middle, with the frontal part somewhat produced, but without any true rostrum; postero-lateral corners not produced. The 2 succeeding segments well developed, with rounded epimeral 136 plates; the 2 posterior trunk-segments, however, very small and not produced at all laterally. Tail normally developed, and composed in female of 4, in male of 5 segments. Caudal rami comparatively small. Anterior antennae resembling in structure those in Artotrogus, though somewhat coarser; those in male (according to Scott) distinctly hinged, but without supplementary sesthetasks. Posterior antenna) very powerfully developed and strongly clawed at the end, outer .ramus present as a delicate setiferous lamella. Siphon obsolete, the 2 lips being scarcely at all produced. Mandibles terminating in a simple point. Maxilla? with 2 very unequal lobes. Maxillipeds comparatively slender, and of quite normal structure. Only 3 pairs of natatory legs present, 1st pair with both rami only composed of 2 joints. 4th pair of legs wanting, or only present as a very slight rudiment. Last pair of legs represented by a small bisetose joint accompanied outside by the usual bristle. BemarJcs. — This genus was established in the year 1893 by Scott, to include a peculiar Copepod, P. RichanU, found by him on the Scottish coast; and subsequently also observed by Giesbrecht. The generic name proposed by Scott is somewhat inappropriate, as the affinity of this genus to Artotrogus is a very remote one. The genus comprises as yet 2 nearly- allied species, one of which will be described below. 75. Parartotrogus aretieus, Scott. • (PI. LXXTX). Parartotrogus Eichardi, var. arctica, Scott, Ou some Entomostraca collected in the Arctic Seas; Ann. Mag. Nat. Hist., Ser. 7, Vol. VIII, p. 352, PI. VI. Specific Characters. — Female. Body comparatively more slender than in the type species, with the anterior division less dilated, and oval in outline. Cephalic segment very large, occupying about half the total length, but not nearly so much expanded in the middle as in P. Richardi, the lateral edges being evenly arcuate; frontal part conspicuously exserted and broadly truncated at the end. Epimeral plates of the 2 succeeding segments well defined and rounded at the end. The last 2 trunk-segments abruptly much narrower and subequal in size. Tail about equalling in length half the anterior division; genital segment fully as long as the 3 succeeding segments combined, and gradually widening anteriorly, forming on each side in front a somewhat projecting angle; anal segment longer than the preceding one. Caudal rami somewhat longer than they are broad and rather far apart, apical setae comparatively short, the inner mediate one scarcely exceeding half the length of the tail. Anterior antennse not quite attaining half the length of the cephalic segment, and somewhat bent at the base. 137 being composed of 9 joints rather densely clothed with short curved setae; 2nd joint the largest and rather broad at the base; terminal joint nearly as long as the 2 preceding ones combined, and carrying at some distance from the end the usual sesthetask. Posterior antennae exceedingly powerful and exhibiting a some- what sigmoid curvature, penultimate joint much the largest, terminal joint short and thick, carrying on the end a very strong curved claw accompanied inside by another much smaller claw; outer ramus forming a narrow, lancet-shaped lamella attached near the end of the 2nd (basal) joint, and provided with 3 small bristles. Mandibles comparatively short, and terminating in a simple point. Maxilla? with the outer lobe very small and provided at the tip with 3 com- paratively short subequal setae ; inner lobe widening considerably distally, spatu- late in form, and carrying on the transversely truncated extremity 3 ciliated spines and 2 abruptly recurved slender and densely ciliated setae. Anterior maxillipeds with the dactylus rather slender, biarticulate, and provided beyond the middle with a small secondary spine, tip sharply pointed. Posterior max- illipeds with the hand somewhat fusiform, and provided at about the middle of the inner edge with a ciliated seta; dactylus slender, triarticulate, with no spine inside the 1st joint, terminal claw occupying about half the length of the dactylus. 1st pair of legs with no seta inside the proximal joint of the outer ramus, distal joint of this ramus with 3 very slender spines outside; distal joint of inner ramus rather large, with 7 setae, one of which issues from the outer edge. The 2 suc- ceeding pairs of legs with both rami distinctly 3-articulate and rather slender, spines of outer ramus dagger-shaped; inner ramus with the terminal joint produced at the end into 2 dentiform projections, between which in the 2nd pair 2 sub- equal setse are affixed, in the 3rd pair only a single dagger-like spine; number of setae on the inner ramus of the latter pair somewhat reduced, the middle joint having only a single seta and the terminal joint 2 setae inside. 4th pair of legs present as a small bisetose joint attached to each side of the corresponding segment and accompanied outside by a small bristle. Free joint of last pair of legs of somewhat larger size and provided with 3 setae, 2 apical and one lateral. Male (according to Scott) very like the female in its outward appearance, but of smaller size. Colour in female pale yellow, with darker translucent ovarial tubes and with some slight ochraceous pigmentary patches on each side of the cephalic segment and trunk; eye bright red and occurring unusually far back. Length of adult female 0.80 mm. BemarJcs. — This form is closely allied to the type species, P. Eichardi Scott, and was indeed regarded by that author as merely a variety of this species. J8 — Crustacea, 138 It ouglit, evidently however, in my opinion to be considered as specifically distinct, as it differs conspicuously not only in the more slender form of the body and the far less expanded cephalic segment, but also in some of the structural details. Thus the inner ramus of the 3rd pair of legs is distinctly 3-articulate, whereas in the type species it is composed of only 2 joints; and the 4th pair of legs, which in P. Rkhardi is wholly absent, is represented by a well-marked, though very small rudiment. Finally, the distal joint of the inner ramus in the 1st pair of legs has 2 setaj more than in P. Richardi. Occurrence. — Two or three female specimens of this form were collected, many years ago, at Kval0, on the Nordland coast, from a depth of 40— 50 fathoms. Distribution. — Arctic Sea, off Spitsbergen and Nova j a Zemlia (Scott). Gen. 35. CanCeriUa, Dalyell, 1851, Syn: Caligidium, Claus (male). Generic Characters. — Form of body very dissimilar in the two sexes, being exceedingly short and stout in female, in male much more slender. Cephalic segment in female greatly inflated, in male sub-depressed ; rostral pro- jection in both sexes obsolete. The succeeding segment well marked, with the epimeral parts less distinctly defined in female than in male ; the 3 remaining trunk-segments in both sexes imperfectly developed, without any epimeral plates. Tail in female very short and composed of only 3 segments, in male more pro- duced and 5 articulate. Caudal rami smaller in female than in male. Anterior antennae in female comparatively short, with the number of joints considerably reduced ; those in male not at all hinged, but of larger size and composed of a greater number of joints, being moreover provided with numerous recurved sensory filaments. Posterior antennae in both sexes distinctly prehensile, terminating in a strong claw, outer ramus absent. Siphon faintly indicated by a slight pro- longation of the lips, and turned anteriorly. Mandibles with the extremity slightly dilated and indistinctly denticulated. Maxilla3 with only a single lobe turned inwards. Both pairs of maxillipeds short and stout, especially in female. 4th pair of legs absent in both sexes. All the remaining legs in female reduced, and unfit for swimming; the 2 anterior pairs in male natatory, 1st pair smaller and less perfectly developed than 2nd, which are quite normal, with both rami 3-articulate. Last pair of legs in both sexes small, uniarticulate, 139 RemarTis. — This genus was established as early as tlie year 1851 by the English naturalist Dalyell, to include a peculiar parasite found by him on a species of brittle-stars. The systematic position of the genus has long remained very uncertain ; but Giesbrecht clearly pointed out its near relationship to the siphono- stomous Cyclopoidse (Asterocheridse) and particularly to the genus Parartotrogus of Scott. I also fully agree with Giesbrecht, that the genus Caligidium of Claus ought to be regarded as a synonym, being founded on adult males belonging to this genus. 76. Caneerilla tubulata, Dalyell. (PI. LXXX). Caneerilla tubulata^ Dalyell, The powers of the Creator, Vol. 1, p. 233, PI. LXII, rigs. 1—5. Syn: Caligidmm vagabundum, Claus. (adult male). Specific Characters. — Female. Body very short and stout, almost cordi- form in shape, with the anterior division greatly inflated, transversely ellipsoid in outline, the width considerably exceeding the length. Cephalic segment occu- pying by far the greater part of the body, free edges strongly curved and minutely hairy in their anterior part, front very slightly produced. The succeeding segment with the epiraeral parts less distinctly defined, forming part of the hind boundary of the anterior division; the remaining trunk-segments imperfectly developed and only visible as narrow stripes. Tail very short, with the genital segment exceedingly dilated, being nearly 3 times as broad as it is long, and projecting behind on each side in an angular corner; anal segment larger than the pre- ceding segment, and somewhat contracted distally. Caudal rami comparatively small and rather far apart, apical setae short, the inner mediate one being, as usual, the longest. Anterior antennae comparatively small and composed of only 6 joints clothed with short curved setae; 1st joint much the largest and rather broad ; terminal joint about the length of the 2 preceding ones combined, and carrying near the end a comparatively small aesthetask in addition to the setae. Posterior antennae very strong and highly chitinized; 1st joint rather short, the 2 succeeding ones of about equal size, terminal joint somewhat shorter, but con- spicuously widening distally, apical claw exceedingly strong and curved. Maxillae with the terminal lobe oblong in form and provided with 3 spreading non-ciliated setae of moderate length and accompanied by a small bristle. Both pairs of maxillipeds short and stout, with the dactyli not much produced, but rather coarse. 1st pair of legs consisting each of a thickish basal part carrying outside a small bristle, and 2 uniarticulate rami, the outer one lamelliform and edged with 6 comparatively short simple setae, one inside, 2 at the tip, and 3 outside; 140 inner ramus very small, cylindric in form, and carrying 2 minute setse on the tip. 2nd pair of legs much smaller than the 1st and farther from the median line, basal part less perfectly defined, though carrying outside the usual bristle; outer ramus represented by a narrow oblong joint edged outside with 6 very minute and somewhat unequal bristles ; inner ramus reduced to a minute conical process. 3rd pair of legs extremely small and rudimentary, being only represented by a minute bisetose joint, without any accompanying bristle outside. 5th pair of legs likewise uniarticulate, but slightly larger than 3rd, and accom- panied outside by the usual bristle. Ovisacs globular, projecting on each side, and rather large, in some cases almost attaining the size of the whole body. Male very unlike the female in its outward appearance, and of much more slender form of body. Cephalic segment occupying about half the total length, and oval in outline, being scarcely as broad as it is long, lateral edges evenly cuved, frontal part obtusely truncated. 2nd segment normally developed, with the epimeral plates well defined and triangularly pointed behind. The 3 succeeding trunk-segments very small and narrow, not being at all expanded laterally. Tail nearly half as long as the anterior division and composed of 5 well-defined segments, the 1st of which (the genital segment) is much the largest and almost quadrate in outline, containing, as a rule, on each side a rounded spermatophore; anal segment somewhat larger than the preceding one. Caudal rami considerably more produced than in female, being more than twice as long as they are broad, and slightly tapered distally; inner mediate seta very long, attaining almost half the length of the body; the other setae comparatively short. Anterior antennae much larger than in the female and composed of 10 well defined joints, being not at all hinged, but provided with numerous delicate sensory filaments curving backwards and especially densely crowded on the 1st very large joint. Posterior antennae of exactly the same structure as in the female, though somewhat less strong. Oral parts likewise very similar, except that the maxillipeds are a little less robust. Legs, however, rather dissimilar, the 2 anterior pairs being much more fully developed and adapted for swimming. 1st pair of legs with the basal part of normal appearance, and distinctly biarticulate ; outer ramus resembling in shape and armature that in female, but comparatively larger and having the marginal setae distinctly ciliated; inner ramus distinctly biarticulate and nearly as long as the outer, proximal joint small, with a single seta inside, distal joint oblong oval, and edged with 5 ciliated setae. 2nd pair of legs quite normally developed, with both rami 3-articulate and armed in the usual manner with spines and setae. 3rd pair of legs exhibiting exactly the same rudimentary condition as in the female. Last pair of legs with the free joint Ascomyzontidse. Copepoda Cyclopoida. PI. LXV. G. O. Sars, del. Leptomyzon elegans, (A. Scott). Ascomyzontidae. Copepoda Cyclopoida. PI. LXVI. G. O. Sars, del. Scottocheres elongatus, Scott. Acontiophoridse. Copepoda Cyclopoida. PI. LXVII G. O. Sars, del. Acontiophorus scutatus, Brady. Myzopontiidse. Copepoda Cyclopoida. PI. LXVIII G. O. Sars, del. Myzopontius pungens, Gsbr. Myzopontiidae. Copepoda Cyclopoida. PI. LXIX. GO. Sars, del. Neopontius angularis, Scott. Dyspontiidae. Copepoda Cyclopoida. PI. LXX. G. O. Sars, del. Dyspontius striatus, Thorell. Dyspontiidae Copepoda Cyclopoida. PI. LXXI. G. O. Sars, del. Cryptopontius brevifureatus, Gsbr. Dyspontiidse. Copepoda Cyclopoida. PI. LXXII. G. O. Sars, del. Arctopontius expansus, G. O. Sars. Dyspontiidae. Copepoda Cyclopoida. PI. LXXIII. G. O. Sars, del Bradypontius magniceps (Brady). Dyspontiidse. Copepoda Cyclopoida. PI. LXXIV. G. O. Sars, del. Bradypontius papillatus (Scott). Dyspontiidae. Copepoda Cyclopoida. PI. LXXV. G. O. Sars, del. Bradypontius major, G. O. Sars, n. sp. Dyspontiidae. Copepoda Cyclopoida. PI. LXXVI. G. O. Sars, del. Bradypontius caudatus, G. O. Sars, n. sp. Dyspontiidae. Copepoda Cyclopoida. PI. LXXVII. \\i\y%' G. O. Sars, del. Cribropontius Normani (Brady). Artotrogidae. Copepoda Cyclopoida. PI. LXXVIII. G. O. Sars, del. Artotrogus orbicularis, Boeck. Cancerillidse. Copepoda Cyclopoida. PI. LXXIX. G. O. Sars, del. Parartotrogus arcticus, Scott. Cancerillidae. Copepoda. Cyclopoida. PI. LXXX. G. O. Sars, del. Cancerilla tubulata, Dalyell. 141 oblong oval in form, and, in addition to the apical bristles, provided with 2 finely ciliated setae on the inner edge. Body in female of a clear yellowish grey colonr, with translucent olive- green ovarial cells and likewise greenish ovisacs; that of male highly pellucid, exhibiting within the anterior part scattered reddish-orange oil-bubbles; eye much larger than in female, and bright red. Length of adult female amounting to 1.10 mm., of male to 0.90 mm. Remarks. — The female sex of this peculiar Copepod has long been known; but it is only in recent times that the existence of the male sex has been satis- factorily ascertained. True, a male specimen was observed by Claus as early as the year 1889; but its relation to Cancerilla tiibiilata of Dalyell was not recognised by that author, who did not hesitate to establish for it, not only a new species, but even a new genus. There cannot in my opinion be any doubt, that Giesbrecht was quite right in considering Callgidium vagabiindiim of Claus to be the adult male of Cancerilla tiibulata, and that the description and figure given by Canu of the supposed male Cancerilla only refer to a quite immature specimen. The remarkable sexual dimorphism occurring in the present form may be easily explained from the sedentary habits of the female, causing in the latter a considerable reduction of the sensory and locomotory apparatus, and at the same time affecting the general form of the body. Occurrence. — I have met with the female of this curious form occasio- nally, off both the south and west coasts of Norway, and always attached in the very same manner ventrally to the base of one of the arms of the common brittle-star, Amphiura squamaia. Its attachment is eifected by the strongly hooked posterior antennae, and is so firm that it is very difficult to detach it without breaking off those appendages. It is indeed very probable that the animal remains attached in the place it has chosen for the rest of its life, being quite unable to move about in the water. The adult male 1 have taken free in the sea in 3 different localities of the Norwegian coast, viz., at Riser and Korshavn, on the south coast, and at Magero, outside the Trondhjem Fjord, only a single specimen being found in each locality. Distribution. — British Isles (Dalyell), coast of France (Canu), Mediter- ranean, at Trieste (Claus) and Naples (Giesbrecht). Crustacea. 142 Section 3. Poecilostoma. General Characters.— Anienov antennae in male not hinged. Posterior antennae without any outer ramus, and generally adapted for prehension. Oral parts not adapted either for mastication or for suction. Mandibles wanting. Maxillae with the terminal part variously modified for conveying food to the mouth, and provided outside with a flap-shaped setiferous palp or exopodite. Anterior maxillipeds never prehensile. Posterior maxillipeds trans- formed in male to powerful grasping organs. Natatory legs, as a rule, well developed. Last pair of legs, when present, extended laterally, uni-or biarticulate. Remarks. — The Cyclopoids comprised within this section differ materi- ally from those included in the 2 preceding sections by the structure of the mouth-organs, which are not adapted either for mastication or for suction, but more properly for licking up finely dissipated nourishing particles from the surface of various organisms or from the wall of their inner (branchial) cavities. In accordance therewith the chief masticating organs, the mandibles, are entirely wanting, and the number of oral appendages of course reduced to 3 pairs only, viz., the maxillae and the 2 pairs .of maxillipeds. I am well aware that the above ihterpretation of the mouth-organs, which agrees, as will be seen, with that originally set forth by Thorell, is quite at vari- ance with the view generally adopted by recent carcinologists on the autho- rity of Glaus, according to which the usual number of oral limbs should be present, the foremost of them representing the true mandibles. There are, however, several serious objections to be urged against the correctness of this altered view of the oral apparatus. Indeed, on a careful examination of the mouth-organs in various types of the present section, I am led to the con- clusion that the view insisted on by Glaus and accepted by most recent authors cannot be maintained, and that we must recur to the interpretation originally given by Thorell as the only one acceptable. As to the number of oral li»mbs, only 3 pairs are in reality disting- uishable, as stated by Thorell. The assumption of the presence of a 4th pair between the 2 anterior ones rests entirely on a miscomprehension, a part of the foremost pair having been erroneously taken for an independent limb. This part, generally described as a maxilla, is always found firmly attached to the outer side of the foremost pair of limbs, and represents in reality, as opined by Thorell, the palp or exopodite of those limbs. Though in a few cases this exopodite may assume a somewhat maxilla-like appearance, it presents 143 itself in the great majority of forms as an insignificant appendage turned backwards, or from the mouth, and attached in much the same manner as in other Copepoda. That this foremost pair of oral limbs, together with their palpiform appendage, cannot be regarded as the mandibles, but must represent, as justly opined by Thorell, the true maxillae, is evident not only from their place far behind the antennal area, but also from their relation to the oral aper- ture. The exact position of the latter is not always easy to determine, because it is more or less completely covered by a lamellar anterior lip; on a closer examination, however, it will invariably be found that the said I'mbs are not placed, like the mandibles, at the sides of that aperture, but decidedly behind it, turning their extremities more or less forwards, precisely as do the maxillae in other Copepoda. The armature also of these limbs is very different from that generally met with in the mandibles, and in some cases at least (Clausi- diidae) exhibits an unmistakable resemblance to that found in some of the gnathostomous Cyclopoida, for instance in those belonging to the family Cyclopidce. It will finally be noticed that whereas the mandibles in several cases are quite destitute of palps, these appendages are almost invariably found in the maxillae. Thorell describes all the oral limbs as maxillae (m' — m'); but, according to the usual terminology, the 2 posterior pairs should more properly be named maxillipeds. About the parasitic nature of the Copepods belonging to the present section there cannot be any doubt; but in many instances the hosts infested by them have not yet been ascertained. The parasitism is in every case, like that of most of the siphonostomous Cyclopoida, rather incomplete or merely temporary, the animals being able easily to change their place and to move freely through the water. Somewhat more sedentary are of course the habits of such forms as live in the branchial cavity of Ascidians or within the valves of different Mussels; though these forms also may at times be able to leave their hosts. Only a few forms are stated to be true fish- parasites, viz., the species of the genera Bomolochus, Ergasiliis and ThersUina; but by far the greater number seem to be confined to invertebrate animals belonging to many different groups e. g. Echinoderms, Worms, Mollusca, Tunicata. A number of forms belonging to this section lead a true pelagic life, being constantly found in the open sea, and probably at times infesting some of the larger pelagic animals. This is the case with all the known forms be- longing to the 3 families Oncceldce, Corycmdce and Sapphirlnidce.^) ') The parasitism of some species of Sapphirina on Salpoe has long been i&■ p-mm ;il 6. O. Sars, del. Oncasa borealis. 6. 0. Sars Oncaeidae— Corycaeidae Copepoda Cyclopoida PI. cix /■/*^r.2 w J 'a'/ '7,/ f \ /.?. J iff ^ M' 1 XJi \ ^ -^"o G O. Sars, del. 1. Oncaea similis, G. O. Sars 2. Corycaeus anglicus, Lubbock d" Corycaeidae Copepoda Cyclopoida PI. ex 6. O. Sars, del. CorycaBus anglicus, Lubbock ? Ergasilidae Copepoda Cyclopoida PI. CXI 6. O. Sars, del. Ergasilus Sieboldi, Nordm. Clausiidae Copepoda Cyclopoida PI. CXII ^'J^ ;f2 /' I — >v x"^- / t r~^ ItW v.^ ^0^ 'S ^. \ \ \. G. O. Sars, del. Conchocheres malleolatus, G. O. Sars Eunicicolidae Copepoda Cyclopoida PI. CXIII 6. O. Sars, del. Eunicicola Clausi, Kurz Oithonidas Copepoda Cyclopoida PI. cxiv 6. O. Sars, del. Paroithona parvula, Farran Cyclopjnidae Copepoda Cyclopoida PI. cxv . ^-^ 6. O. Sars, del. 1. Cyclopina euacaniha, G. O. Sars 2. „ pygmaea, 6. 0. Sars Ascomyzontidae Copepoda Cyclopoida PI. cxvi j^i.-'i'-'w ^/L\i V: 6. O. Sars, del. Scotiomyzon gibberum, (Scott) Lichomoigidae Copepoda Cyclopoida PI. CXVII G. O. Sars, del. Pseudanthessius dubius, 6. 0. Sars Copepoda LichomolgidzB— Oncaeidae CyClOpOJCla PI. CXVIII /Csv-'m" ' ' m\ ^^ u /? Ml ' / ! \ e. O. Sars, del. 1. Lichomolgella pusilla, 6. O. Sars 2. Onc«a minuta, 6iesbr. AN ACCOUNT OF THE CRUSTACEA OF NORWAY AN ACCOUNT OF THE CRUSTACEA OF NORWAY WITH SHORT DESCRIPTIONS AND FIGURES OF ALL THE SPECIES BY G. 0. SARS PROFESSOR OF ZOOLOGY AT THE UNIVERSITY OF CHRISTIANIA VOL. VII COPEPODA SUPPLEMENT WITH 76 AUTOTYPIC PLATES BERGEN PUBLISHED BY THE BERGEN MUSEUM SOLD BY ALB. CAMMERMEYER'S FORLAG, CHRISTIANIA 1921 BERGEN, A/S JOHN GRIEGS BOKTRYKKERI OG N. NILSSEN & S0N PREFACE. By the present Volume my Account of the 3 leading divisions of Copepoda, the Calanoida, Harpacticoida and Cyclopoida is finely concluded. Yet there still remains a considerable bulk of Copepoda of a more or less pro- nouncedly parasitic nature, the most familiar of which are the genuine Fish- parasites, the Caligoida and the Lemceoida. These 2 divisions have however recently been so carefully treated of in the excellent and beautifully illustrated work of Th. & A. Scott (British parasitic Copepoda), that a renewed account of these forms appears to be less needed. On the other hand, 2 other anomalous divisions of Copepoda, likewise in some measure parasitic in habits, but not included in the above mentioned work, viz., the Monstrilloida and the Notodelphyoida, may be more worthy of a careful reexamination. It is indeedmy purpose in the next Volume now in preparation to give an exhaus- tive account of the Norwegian forms referable to these 2 interesting divisions, which in some respects show relations partly to the free-living Copepoda, partly to the true parasites. I take the occasion again to express my most sincere thanks to the Direction of the Bergen Museum for the interest it has shown for my work and for the kindness in giving me an opportunity of still continuing it, in spite of the many obstacles which in these difficult times have arisen against the printing and publication. Q. O. Sars. INTRODUCTION. The considerable number of additional species observed during the latter years has induced me to publish a supplementary Volume to the Copepoda, containing descriptions and figures of these species, and embracing all the 3 leading divisions treated of in the 3 preceding Volumes. The far greater number of these species has been derived from the extensive division Har- pacticolda; but also of Calanoida and Cyclopoida several interesting forms are added in the present Volume. Most of the species here described have been picket up from bottom-samples taken at different times, and chiefly in 2 local- ities on our southern coast, viz., Korshavn and Riser, some also from mixed collections of Copepoda made in the same localities. It is evident that the study of the present order of Crustacea still remains to be a very promising one, and I do not doubt that continued investigations in other places of our extensive coast will reveal many additional forms worthy of note. 1 — Crustacea. Calanoida. Fam. Phaennidae. Gen. Xanthocalanus, Giesbr. Remarks.— Oi this genus, in addition to the 2 species originally recorded by Giesbrecht from the Mediterranean, several new forms have been described in recent time from the northern Ocean, some of them being, however, so nearly related, the ones to the others, that they, without a very close examina- tion, may easily be confounded. As moreover, owing to the great britlleness of the appendages, most specimens obtained are more or less defective, the determination of the species belonging to the present genus is connected with no small difficulty. I have myself formerly, under the name X. borealis, con- founded 3 different species. The one originally described by the present author under that name from the Nansen Expedition is a true arctic form, which does not occur off the coast of Norway. It has recently been identified, though with some doubt, by Mr. With with X. hirtipes Vanhoeffen. The Norwegian form recorded in Vol. IV of the present work as X. borealis is quite certainly not identical with the arctic species, differing, as it does, both by its much inferior size and by the rather unlike structure of the last pair of legs. I was seduced to this erroneous identification by the occurrence in my material of some few specimens, in which the last pair of legs, by the complete fusion of the 2 outer joints and the presence of only 3 apical spines, exhibited a certain resemblance to these appendages in the arctic form. These specimens I supposed to be young, not yet fully developed females, and that accordingly the last pair of legs changed their character according to age. This supposition has, however, turned out to be quite wrong. I have subsequently found fully adult specimens with the very same structure of the last pair of legs, and I have convinced myself that they are referable to a well defined species, which will be described below. For the other Norwegian species I propose the name X. fallax. A 3rd Norwegian species has been described in the present work as X. proplnqvus. The most reliable character for distinguishing the species of the present genus is unquestionably the structure of the last pair of legs. 1. Xanthocalanus minor, Giesbr. (PI. I). Xanthocalanus minor, Giesbrecht, Fauna und Flora des Golfes von Neapel: Pelagische Cope- poden, p. 286 (footnote), PI. 12, Fig. 32. Specific Characters. — Female. Body moderately slender, with the anterior division oblong oval in form, greatest width not nearly attaining half the length and occurring somewhat behind the middle; dorsal face only slightly vaulted. Cephalosome nearly as long as the exposed part of the trunk, and exhibiting behind the middle dorsally a distinct transverse suture; anterior extremity narrowly rounded. Rostral filaments of moderate length and abruptly reflexed. Last trunkal segment completely coalesced with the preceding one; lateral lobes triangularly produced, and extending somewhat beyond the middle of the genital segment. Urosome comparatively short, scarcely exceeding in length V4 of the anterior division; genital segment only slightly protuberant below, and about the length of the 2 succeeding segments combined; anal segment very small. Caudal rami scarcely longer than they are broad; apical setae well developed and somewhat divergent, the innermost but one, as usual, considerably longer than the others. Anterior antennae rather elongated, ex- tending, when reflexed, to the end of the caudal rami. Posterior antennae and oral parts almost exactly as in X. fallax. Natatory legs likewise of a very similar structure, though having the spinules of the inner ramus fewer in number. Last pair of legs, however, rather unlike those in the said species, the outer 2 joints being, as in X. borealis, completely coalesced to an elongated some- what curved piece armed at the end with only 3 comparatively short, subequal spines, edges of the piece nearly smooth, with only a few cilia at the outer curvature. Body in the living animal highly pellucid, with only a faint rosy pig- ment at the end of some of the segments. Length of adult female reaching to 2.70 mm. Remarks.— The figure given by Giesbrecht of the last pair of leg in his X. minor agrees pretty well with those appendages in the above-described form, and I think therefore that I am right in identifying both, though no other figures were given by Giesbrecht, nor any description of the species, The length of the body is said to be only 1.20 mm.: but I suppose that an exact measurement may have been rendered difficult by the bad condition of the solitary specimen observed by that author. As above stated, the present species was formerly confounded by me with X. fallax (at that time recorded as X. borealis), to which species it cer- tainly bears a close resemblance. It is however rather inferior in size and of somewhat more slender form of body, differing moreover in the greater length of the anterior antennae, and more particularly in the structure of the last pair of legs, which more resembles that in the arctic species, X. borealis. In the latter, however, these appendages are everywhere densely hirsute, and the apical spines are much stronger, nearly claw-like. Occurrence, — Adult female specimens of the present species have been found in 3 different localities of the Norwegian coast, viz., at Riser, Stavanger, and in the upper part of the Trondhjem Fjord. In all '3 localities it occurred only occasionaly and in comparatively shallow water. Distribution. — Mediterranean (Giesbrecht). Fam. Stephidae. Gen. Stephos, Scott. Remarks.— Two well-defined species of this genus have been de- scribed in Vol. IV of the present work. A 3rd species is now added, to be described below. 2, Stephos minor, Scott. (PI. II). Stephos minor, T. Scott, Tenth Ann. Report of the Fishery Board for Scotland, Part III, p. 245, PI. VIII, figs. 1—13. Specific Characters.— Female. Body resembling in shape that of S. Scotti G. O. Sars, the anterior division being regularly elliptical in outline and evenly vaulted dorsally; greatest width about half the length. Cephalic segment very large, with the front obtusely truncated and exhibiting no trace of rostral filaments. Lateral parts of last trunkal segment perfectly symmetrical and not lamellarly expanded. Urosome equalling in length about V3 of the anterior division; genital segment somewhat protuberant below, and about the length of the 2 'succeeding segments combined. Caudal rami scarcely longer than they are broad; apical setae rather slender, the innermost but one, as usual, the longest and considerably exceeding the length of the urosome. Anterior antennae comparatively shorter than in S. Scotti, scarcely extending, when reflexed, beyond the genital segment. Posterior antennae, oral parts and natatory legs of a structure very similar to that in S. Scotti. Last pair of legs rather small, with the distal joint conical in form, and only armed with a single denticle inside at some distance from the tip; outer edge with a small bristle opposite the denticle. Male much smaller than female, with the urosome more slender and 5-articulate. Last pair of legs built on the same type as in the other species, though exhibiting well-marked specific differences, as seen from the figure here given. Body in both sexes highly pellucid and without any obvious pigment. Length of adult female 0.73 mm., of male 0.60 mm. Remarks. — The present species, first described by Scott, is nearly allied to 5. Scotti G. O. Sars, but of much smaller size, and moreover well disting- uished by the somewhat storter anterior antennae and by the structure of the last pair of legs in both sexes. Occurrence. — Several specimens of this form were taken in a single place at Korshavn from a depth of about 15 fathoms. I have also found it occasionally at Ris0r in about the same depth. Distribution. — Scottish coast (Scott). Gen. Parastephos, G. O. Sars. Remarks.— Ih'xs genus was established in the year 1903 by the present author, to include a peculiar Copepod, of which at that time only a solitary male specimen was obtained. Subsequently Mr. Scott found also the female, and the perplexing characters distinguishing this sex fully prove the validity of the present genus. I have been fortunate enough to find a few female specimens off the Norwegian coast, and I am thus enabled to confirm th^ statements given by Scott about this sex, 3. Parastephos pallidus, G. O. Sars. (PI. III). Parastephos pallidus. G. O. Sars, Account of the Crustacea of Norway, Vol. IV, p. 65, Pi. XLIV. Specific Characters.— Female. Body very slender, with the two chief divisions sharply marked off from each other, the anterior one regularly oblong oval in form. Cephalic segment with a faint transverse suture behind the middle dorsally; front blunted, without any traces of rostral filaments. Last truncal segment completely fused with the preceding one, and having the lateral parts only slightly produced. Urosome very powerfully developed, equalling in length about 2/3 of the anterior division, its 3 anterior segments expanded behind to elevated circular ridges densely clothed with delicate recurved spinules; genital segment scarcely at all protuberant below and, as usual, the largest, though not much exceeding in size the succeeding segment; anal segment well developed and of sub-cylindrical form; without any elevated ridge behind. Caudal rami scarcely longer than they are broad; apical setae slightly divergent, the innermost but one on left ramus remarkably produced, being nearly twice as long as that on the right ramus. Anterior antennae of the very same structure as in the male, and extending, when reflexed, to the end of the genital segment. Posterior antennae and oral parts exactly as in the male. Natatory legs of quite normal structure and resembling those in the genus Stephos. Last pair of legs likewise built on the same type as in that genus, but of comparatively much larger size and pronouncedly asym- metrical, the left leg being considerably longer than the right; distal joint in both legs conically produced and armed outside with a row of 12 — 15 coarse denticles, the proximal of which is somewhat remote from the others and of larger size. Body in the living animal semipellucid, of an uniform whitish grey colour, without any obvious pigmentation. Length of adult female reaching to 2.20 mm. Remarks. — Of this form, as above mentioned, only the male sex was formerly observed by me. The female, as usual, is of considerably larger size, and exhibits a most anomalous appearance by the powerful development and peculiar armature of the urosome. The last pair of leg are also remarkable by their comparatively large size, and more particularly by their conspicuous asymmetry, also observed by Scott. Another asymmetry, not mentioned by that author, is found in the extraordinary length of one of the caudal setae on left side. On the other hand has the asymmetry described by the present author in some of the natatory legs of the male specimen at first obtained proved to be quite accidental, as no such asymmetry was found in another male subsequently obtained. Occurrence. — The originally described male specimen was taken at Skjerjehavn, outside the Sogn Fjord. I have subsequently obtained 3 additional specimens of this remarkable form, 2 adult females and one male. Of these the one female was taken at Kopervik, south west coast of Norway, the other female and the male specimen at Riser, the depth in both localities ranging from 50 to 100 fathoms. Distribution. — Scottish coast (Scott). Fam. Pseudocyclopiidae. Gen. Pseudocyclopia, Scott. Remarks.— Only a single species of this genus, P. stephoides Thompson, has hitherto been recorded from the Norwegian coast. I am now enabled to add 2 other species, both described at an earlier date by British authors, and it is very probable that also the remaining 2 species, P. minor and P. caudata Scott, will on a further investigation be found to belong to the fauna of Norway. 4. Pseudocyclopia 6lesbrechti, Wolfenden. (PI. IV, PI. V, fig. 1). Pseudocyclopia Giesbrechti, Wolfenden, Journal of the Marine Biological Association, Vol. VI, No. 3, p. 370, PI. IV. Specific Characters.— Female. Body rather short and stout, with the anterior division considerably vaulted above, and somewhat compressed, ex- hibiting in the dorsal aspect a narrow oblong form, with the greatest width scarcely attaining half the length. Cephalic segment very large and evenly curved in front; rostral prominence triangular, deflexed. Last truncal segment united with the preceding one and deeply emarginated behind in the middle, lateral parts obtusely rounded. Urosome about equalling in length Va of the anterior division; genital segment only slightly protuberant below and about the length of the 2 succeeding segments combined. Caudal rami short, being scarcely longer than they are broad, and somewhat obliquely truncated at the 8 end; apical sets rather strong and partly exhibiting a dense annulation. An- terior antennae only slightly exceeding half the length of the cephalic segment, and composed of 17 joints, the 1st of which, apparently formed by the junction of the 6 or 7 proximal joints, is very large, almost occupying half the length of the antenna. Posterior antennae with the terminal part (inner ramus) com- paratively shorter than in P. stephoides, though a little longer than the outer ramus; the latter 6-articulate, with the 2nd joint somewhat dilated, oval in form, and provided outside with 3 setae, the 3 succeeding joints very small. Oral parts of the structure characteristic of the genus. Natatory legs likewise built on the same type as in the other species, though the rami appear some- what more slender than in P. stephoides and more distinctly spinulose at the end of the joints, those of 4th pair being moreover densely covered with small prickles. Last pair of legs rather short and stout, with the last joint scarcely longer than the middle one and somewhat hand-shaped, terminating in 3 strong diverging digitiform spines of equal length, the outermost one distinctly defined at the base, whereas the other 2 form the immediate continuation of the joint; all 3 spines, as also partly the surface of the joint, coarsely spinulose. Male, as usual, smaller than female and having the urosome more slender and distinclly 5-articulate. Antennae, oral parts and natatory legs scarcely different from those parts in female. Last pair of legs, however, con- spicuously transformed and very asymmetrical; right leg long and slender, termi- nating in a somewhat flexuous point; left leg much shorter, but with the 1st joint considerably tumefied, nearly globular in form, 2nd joint tapered distally and provided at the end with a well-marked rudiment of an appendicular ramus, 3rd joint very narrow and armed at the end with a slender movable claw, outside which are attached a bundle of 3 delicate and closely superposed lamellae. Colour of the living animal not yet ascertained. Length of adult female reaching to 0.90 mm., that of male to 0.79 mm. Remarks. — The present species was first described by Mr. Wolfenden from a solitary female specimen taken off the Shetland isles. Subsequently T. Scott found the same species also off the Scottish coast, and has given a figure with some details of a male specimen. It may easily be distinguished from P. stephoides by the comparatively shorter and stouter form of the body and more particularly by the structure of the last pair of legs in bot sexes. As these appendages were somewhat damaged in the male specimen examined by Scott, the figure he gives of them has turned out to be rather imperfect. Moreover the right leg is described as the left, and vice versa. Occurrence. — Several specimens of this form have been picked up from bottom-samples taken at Korshavn from a depth of about 60 fathoms muddy sand. It also occurs occasionally at Ris0r in about the same depth. Distribution.— ^htWdiW^. (Wolfenden), Scotish coast (Scott). 5. Pseudocyclopia crassicornis, Scott. (PI. V, fig. 2). Pseudocyclopia crassicornis, T. Scott, Tenth Ann. Report of the Fishery Board for Scotland, Part III, p. 246, PI. VII, figs. 15—29. Specific Characters. — Female. Very like the preceding species, as to the general appearance of the body, but of much smaller size. Anterior antennae comparatively shorter, scarcely exceeding half the length of the cephalic segment, and rather thick at the base, being composed of 16 joints, the 1st of which is very large, fully as long as the remaining part of the antenna, and, in addition to the usual short marginal setae, provided with 3 comparatively large aesthetasks. Posterior antennae with the penultimate joint (1st joint of the inner ramus) somewhat dilated in the middle, subfusiform in shape, outer ramus resembling in structure that of the preceding species and a little shorter than this joint. Oral parts and natatory legs of the usual struc- ture. Last pair of legs with the middle joint very short, nearly circular in form; terminal joint much larger, occupying more than half the length of the leg, and armed at the somewhat obliquely truncated extremity with 3 slender spines, the innermost of which is much the longest and, like the middle one, not defined from the joint at the base. Spermatophore, attached to the genital segment, of unusually large size and curving upwards along the dorsal face of the urosome. Male of still smaller size than female, and differing from it in a similar manner to that in the preceding species. Last pair of legs, however, of a somewhat simpler structure; the left leg having no trace of an appendicular ramus at the end of the 2nd joint, and only a single lamella outside the apical claw, which is rather small. Colour in the living animal not yet ascertained. Length of adult female scarcely exceeding 0.71 mm.; that of male 0.68 mm. Remarks.— This form was described by T. Scott in the year 1892 as the type of his genus Pseudocyclopia. It is of much smaller size than the proceding species, and moreover easily distinguished by the shorter and thicker anterior antennae and by the somewhat different structure of the last pair of legs in both sexes. 2. — Crustacea. 10 Occurrence. — I have found this form in the same localities and at about the same depth as the preceding species. At Ris0r only one or two speci- mens were obtained, whereas at Korshavn this form seems to be rather abundant in some places. Distribution. — Scottish coast (Scott). % Fam. Platycopiidae. Gen. Platycopia, G. O. Sars, 1911. Generic Characters. — General form of body resembling that of Pseudo- cyclopia. Last trunkal segment, however, well defined from the preceding one, and urosome composed in both sexes of only 4 segments. Anterior antennae short and stout, though composed of rather a great number of articulations, and only slightly differing in the two sexes. Posterior antennae with the outer, ramus much larger than the inner. Oral parts considerably deviating in struc- ture from the usual Calanoid type. Anterior lip narrowly produced at the end. Mandibles with the masticatory part only slightly expanded, palp comparatively slender, with the outer ramus larger than the inner. Maxillae with the masti- catory lobe very coarsely built, palp comparatively less fully developed than in most other Calanoida. Anterior maxillipeds cyclopoid in structure, the outer joints being armed with stout unguiform spines. Posterior maxillipeds more resembling those in other Calanoids. 1st pair of legs rather unlike the suc- ceeding ones, with both rami imperfectly developed and without true spines; the remaining pairs very strongly built, with the rami broad and flattened, the outer one the larger, and having 2 successive spines outside the 1st joint; natatory setae for the most part converted to short flattened spines. Last pair of legs built on the very same type as the preceding ones; those of male having the outer ramus slightly transformed and alike on both legs. Remarks. — This genus was established by the present author in the year 1911, to include a remarkable deep-water Calanoid, P. perplexa, the closer examination of which revealed a most perplexing mixture of char- acters tending on the one side to the genus Pseudocyclopia, on the other side to Pseudocy clops, though these 2 genera, according to the definition given by Giesbrecht, in reality belong to 2 very different sections of the Calanoida, the 11 first to the Amphascandria, the 2nd to the tieterarthrandria. I think that this premary division of the Calanoida proposed by Giesbrecht, and now generally accepted by carcinologists, may turn out to be a less natural one, and I am also now in doubt about the vaUdity of the 3rd intermediate section, Isoker- andria, added in my earlier account of the Calanoida (Vol. IV of the present work). Indeed, it seems to be very difficult to decide, to which of these 3 sections the present genus should be referred. i) Two nearly allied species of this remarkable genus will be described below. 6. Platycopia perplexa, G. O. Sars. (PI. VI, PI. VII, fig. 1). Platycopia perplexa, G. O. Sars, Archiv f. Mathem. & Naturvidenskab, Vol. XXXI, No. 7, p. 4, Pi. I & II. Specific Characters. — Female. Body short and stout, with the anterior division greatly vaulted above and somewhat compressed, the greatest width not fully attaining the hight and about equalling half the length. Cephalic segment very large, occupying nearly half the length of the whole body, and evenly curved in front; inferior edges somewhat bulging in their anterior part, rostral projection comparatively short and acutely pointed at the end. The 4 succeeding segments densely crowded and of about equal length, though diminishing somewhat both in height and width; last segment deeply emarg- inated behind in the middle and having the lateral lobes rounded at the end. Urosome scarcely exceeding in length Vs of the anterior division and narrow cylindrical in shape; genital segment comparatively small and only slightly dilated; penultimate segment the longest and produced at the end dorsally to 2 juxtaposed lanceolate lappets superposing the anal segment and apparently replacing the usual anal opercle; last segment much smaller than any of the others. Caudal rami short, being only slightly longer than they are broad; seta of outer edge small and attached somewhat in front of the middle; apical setae rather unequal in length, the innermost but one being, as usual, the 1) At this occasion I will mention another instance, which still more seems to debilitate the validity of Giesbrecht's arrangement. On a closer investigation of the Calanoida from the Monaco Expedition instituted in the latter years, I have to my great astonishment found, that in the male of Bathycalanus Richardi G. O. Sars, a form unquestionably nearly allied to Megaca- lanus, the right anterior antenna is very distinctly hinged. According to this character the genus Bathycalanus should of course, if the primary division proposed by Giesbrecht is accepted, not only be wholly removed from the family Calanidce (in the restriction here adopted), but transferred to quite another section of the Calanoida, the Heterarthrandria, an arrangement which in reality would be absolutely unreasonable. 12 longest. Anterior antennae scarcely exceeding half the length of the cephalic segment and gradually tapering distally, being composed of 23 well-defined joints, the 1st of which is much the largest, occupying in length about Va of the antenna, and provided anteriorly, at some distance from the end, with a peculiar strongly developed spiniform appendages curving outwards and ter- minating in a thin filament; the succeeding joints very short and clothed anteriorly with small bristles; terminal joint longer than the preceding ones and narrow linear in form. Posterior antennae of an unusually compact structure, with the outer ramus much larger than the inner and 5-articulate, the first 2 joints considerably dilated. 1st pair of legs much smaller than the others, and having the basal part quite naked; both rami short, biarticulate, with the proximal joint small and unarmed, distal joint of outer ramus carrying 6, that of inner ramus 3 curved setae. The 4 succeeding pairs of essentially equal structure and very coarsely built, though somewhat diminishing in size posteri- orly; 2nd basal joint very large and obliquely truncated at the end, being provided outside near the end with a short spine, inside with a coarsely ciliated seta, which however is wanting on the last pair; both rami distinctly 3-articu- late in all the pairs and rather unequal, the outer one being much the larger; number of spines and setae slightly differing in the different pairs. Male somewhat smaller than female, but very like it in the general outward appearance, though perhaps a little less robust. Anterior antennae with the number of joints somewhat reduced, being only 16-articulate, and moreover differing in the much fuller development of the aesthetasks, the number of which is about 8. Last pair of legs with the outer ramus slightly transformed, being only composed of 2 joints, the distal one rather elongated and somewhat constricted in the middle, with the inner edge quite smooth, the outer armed with 2 rather distant spines, end of the joint transversely truncated and carrying a thin partly ciliated lamella flanked by 2 unequal spines, the outer one of normal appearance, the inner long, styliform and quite smooth. Colour of the living animal not yet ascertained. Length of adult female reaching 0.95 mm., that of male 0.83 mm. Remarks. — This interesting Calanoid was described and figured by the present author in the above-quoted Journal as the type of a new genus and even of a new family. It is now redescribed and new improved figures given. The resemblance, as to the outward appearance, to the species of the genus Pseudocyclopia is rather striking, and may be accounted for as the result of 13 & convergent evolution caused by the adaptation to similar conditions of life. It is undoubtedly, like the species of the said genus, a true bottom-form. Occurrence. — Some few specimens of this remarkable form were picked [up from a bottom sample taken several years ago at Korshavn from a depth of about 60 fathoms, coarse muddy sand. I have not met with it in any other place of the Norwegian coast. 7. Platycopia pygmeea, G. O. Sars, n. sp. (PI. VII, fig. 2). Specific Characters .—Female. General form of body resembling that of the preceding species, though comparatively less robust. Anterior divi- sion considerably compressed and, viewed dorsally narrow oblong in out- line, with the greatest width scarcely exceeding Vs of the length. Urosome very narrow and nearly attaining half the length of the anterior division. Caudal rami much more elongated than in the type species, being more than 3 times as long as they are broad; seta of outer edge attached near the base of the ramus. Antennae, oral parts, and 1st pair of legs exhibiting a structure very similar to that in the type species. The 4 succeeding pairs of legs likewise built on the very same type, though differing in the inperfect segmentation of the inner ramus, its 2 outer joints being wholly coalesced in the 2nd pair and only slightly indicated in the 3 succeeding pairs. Male differing from the female in a very similar manner to that found in the preceding species. Anterior antennae, as in the male of P. perplexa, only composed of 16 joints, the outer 2 of which are rather elongated and narrow. Last pair of legs of a comparatively more compact structure than in the male of the preceding species, with both rami only composed of 2 joints, the outer one armed at the end of the broad, spatulate distal joint with 2 large, sabre-like spines, between which a thin hyaline lamella is attached. Colour of the living animal not yet ascertained. Length of adult female scarcely exceeding 0.60 mm. ; that of male 0.52 mm. Remarks. — The present form is nearly allied to the type species, but evidently specifically distinct, differing not only in its much inferior size, but also in some of the structural details, as pointed out in the above given diagnosis. Occurrence. — Only 3 specimens of this form, one female and 2 males, have as yet come under my notice. They were found in a bottom-sample likewise taken at Korshavn, but from somewhat shallower water, viz., about 30 fathoms, muddy bottom. 14 Fam. Pseudocyclopidae, Gen. Pseudocyclops, Brady. 1 Remarks. — Three species of this genus have as yet been recorded, one from the Mediterranean and 2 from the British coast. One of the latter, P. obtusaius Brady, is described in the 4th Volume of the present work, and I am now enabled to add to the fauna of Norway also the 2nd British species, to be described below. 8. Pseudocyclops crassiremis, Brady. (PI. VIII & IX). Pseudocyclops crassiremis, Brady, Nat. Hist. Trans. Northumberland and Durham, Vol. IV, p. 431, PI. XVII, figs. 1—8. Specific Characters. — Female. Body rather robust, with the anterior division evenly vaulted above and somewhat compressed, seen dorsally, oblong oval in outline and nearly of equal width throughout. Cephalic segment very large, almost occupying half the length of the body, and obtusely rounded in front, exhibiting behind the middle a rather faintly marked transverse suture, inferior edges somewhat expanded in their anterior part. Rostrum very strong, deflexed, and acutely pointed at the tip. Last trunkal segment deeply emar- ginated behind in the middle and partly confluent with the preceding one, being only defined from it by a slight sinus of the inferior edges; lateral lobes broadly rounded at the end. Urosome not nearly attaining half the length of the anterior division; genital segment somewhat larger than the succeeding segment and slightly protuberant below; anal segment very small. Caudal rami scarcely longer than they are broad, and somewhat obliquely truncated at the end; apical setae of moderate length. Anterior antennae about half the length of the cephalic segment, and composed of 17 joints rather densely clothed with comparatively short curved setae; 1st joint much the largest and rather broad, carrying, in addition to the setae, 3 slender aesthetasks. Posterior antennae and oral parts of essentially same structure as in P. obtusatus. Legs likewise rather similar; last pair, however, differing in the shorter and stouter form of the inner ramus, the joints of which, moreover, are almost wholly coalesced. Male somewhat smaller than female and easily recognisable by the more slender and distincly 5-articulate urosome. Rostrum, as in the male of I 15 P. obtusatus, sharply defined at the base, and somewhat smaller than in female. Right anterior antenna conspicuously hinged, with the middle joints rather tumefied, terminal movable part only composed of 3 joints, the 1st of which is produced at the end anteriorly to a slender spiniform process. Last pair of legs exceedingly strong and massive, being built on a similar type to that in the male P. obtusatus, though exhibiting some minor differences, as seen from the figure here given. Body in the living animal highly pellucid and nearly colourless; eye very conspicuous and of a light red colour. Length of adult female amounting to 0.86 mm., that of male to 0.80 mm. Remarks. — This form was first described by Prof. Brady in the above quoted journal, and was subsequently briefly recorded by the same author in his well-known Monograph of British Copepoda. It is nearly allied to P. obtusatus, but of somewhat larger size and more robust form of body, differing moreover in some of the anatomical details, as pointed out in the above diagnosis. Occurrence.— \ have only met with this form in a single locality of the Norwegian coast, viz., at Korshavn, where some few specimens were taken from a depth of about 30 fathoms, muddy bottom. Distribution. — British Isles (Brady). ' Fam. Acartiidae. Gen. Paracartia, Scott, 1894. Generic Characters. — General appearance somewhat resembling that of Acartia; sexual differences, however, much more conspicuously marked. Last trunkal segment in both sexes wholly coalesced with the preceding segment, and in female expanded on each side to a broad wing-like lappet; in male simple, not expanded. Urosome in female short, and composed of only 3 segments, the 1st of which (the genital segment) is much the largest and lamellarly expanded laterally; caudal rami broad, with one of the apical setae converted to a strong spine. Urosome of male slender and composed of 4 well-defined segments, the 1st of which is rather small; none of the caudal 16 setae spiniform. Front in both sexes provided with 2 slender recurved filaments. Anterior antennae in female resembling in structure those in Acartia; right antenna in male conspicuously transformed and strongly hinged. Posterior antennae, oral parts, and natatory legs nearly as in Acartia. Last pair of legs in female comparatively large and confluent at the base, terminal joint claw- like; those in male powerfully developed and very asymmetrical; right leg much the larger and terminating in a slender incurved claw. Spermatophore affixed to the genital segment of the female, accompanied by a thin plate folding upwards on each side of the segment. Remarks.— The name Paracartia was proposed in 1894 by Scott merely to designate a sub-genus of Acartia. I think, however, that the differences are greath enough to warrant this sub-genus to be raised to a true genus associated with Acartia in the family Acartiidce, as defined by the present author (see Vol. IV, p. 147). Scott records 2 supposed species of this genus, both found together in a plankton-sample taken in the bay of Guinea; but, as suggested by Giesbrecht, there can be no doubt that P, spinicaudata is the female and P. dubia the male of one and the same species, to which the latter name has been assigned by Giesbrecht. The Acartia laiisetosa of Kriczagin (= A. ver- rucosa Thompson) is apparently referable to the present genus, though differing in some particulars conspicuously from the species observed by Scott. On the other hand, is the Norwegian form described below very closely allied to that species. 9. Paracartia Grani, G. O. Sars. (PI. X & XI). Paracartia Grani, G. O. Sars, Bergens Museums Aarbog 1904, No. 4, p. 3, PI. I — IV. Specific Characters. — Female. Body comparatively slender, with the anterior division gradually narrowed in front. Wing-like expansions of last trunkal segment very large, triangular, each terminating in an acute point. Urosome scarcely exceeding in length V4 of the anterior division, and some- what constricted in the middle; genital segment fully twice as broad as it is long, forming on each side a lamellar expansion obliquely truncated at the end. Caudal rami conspicuously asymmetrical, the right ramus being considerably broader than the left; marginal setae comparatively short, 2 of them attached to the outer edge; middle apical seta an both rami spiniform, that on right ramus much stronger than that on left. Anterior antennae not fully attaining the length of the anterior division of the body, and apparently composed of 17 or 18 joints, some of the proximal ones being however less distinctly 17 defined. Last pair of legs comparatively strongly built, with the proximal parts completely coalesced in the middle, terminal parts claw-like and coarsely denticulated in their outer part, that on right side conspicuously larger than that on left side. Male of somewhat smaller size than female and very unlike it in its outward appearance. Anterion division regularly oblong oval in outline, with the last segment quite simple, without any lateral expansions. Urosome much more slender and narrow, cylindrical in form, with the 2nd segment the largest. Caudal rami comparatively small and quite symmetrical, marginal setas quite normally developed, none of them being spiniform. Right anterior antenna very strongly hinged and somewhat resembling in structure that in male Pontellidce ; proximal part of the middle section considerably tumefied and composed of 4 firmly connected joints, distal part of that section formed by a single elongated and highly chitinised joint movably articulated both with the proximal part and with the succeeding terminal section; the latter com- posed of 4 joints, the 1st of which is the largest and armed in front with a long, dark-coloured claw-like spine. Last pair of legs powerfully developed and very asymmetrical, the right leg being more than twice as long as the left and exhibiting inside 2 differently shaped lappets, apical claw very slender and abruptly curved inwards; left leg provided at the end with 2 peculiar appendages, the outer one somewhat lamellar and densely ciliated outside, the inner terminating in a styliform point. Colour of the living animal not yet ascertained. Length of adult female only slightly exceeding 1 mm.; that of male about the same. Remarks.— This form has been fully described and figured by the present author in the above-quoted journal, and its close relationship to the tropical species recorded by Scott pointed out. Indeed, after having had the opportunity of examining some specimens of the latter species kindly sent to me from Scott, I am now much inclined to regard it as merely a somewhat depauperated form of that species left behind from a far remote period, in which a considerably warmer climate and a more southern fauna prevailed in our country. Occurrence. — The present interesting form was found by Prof. H. Gran very abundantly in an oyster-bed (Espevigpollen) located at Tysnes, south of Bergen. It also occurred, though more sparingly, in another neighbouring bed (Sel0pollen). In both these beds the water holds during the summer a very high and uniform temperature amounting to no less than -\- 30° C, and also 3 — Crustacea. 18 in winter the temperature is comparatively high (up to -|- 10° C). It is evident, that by this exceptional temperature, in connection perhaps with the chemical constitution of the water, quite particular conditions of life are created, which may have favoured the continued existence of the present southern form in the above mentioned isolated basins. Harpacticoida. Fam, Longipediidae. Gen. Sunaristes, Hesse. 10. Sunaristes paguri, Hesse. (PI. XII). See Vol. V, p. 15, PI. VI & VII. specific Characters. — Male. Body still more slender than in female, with no sharp demarcation between the two chief divisions, the posterior seg- ments of the trunk being scarcely wider than those of the urosome and of simple cylindrical form, without any distinct epimeral plates. Urosome com- posed of 5 well defined segments, the 1st of which (the genital segment) is only slightly larger than the succeeding one, and somewhat protuberant at the end below; last segment, as in the female, much smaller than the others. Caudal rami of same appearance as in the female. Anterior antennae very strongly built, and pronouncedly subcheliform, each terminating in a power- fully developed hand, with a well-marked projecting angle in front defining the palmar edge, against which the clawshaped terminal joint, or daetylus, admits of being impinged. Posterior antennae and oral parts exactly as in the female. Natatory legs likewise very similar, with the exeption of the 2nd pair, the inner ramus of which is conspicuously transformed, its 1st joint being produced at the end outside to a very strong mucroniform process extending beyond the middle of the terminal joint. Last pair of legs still more rudimentary than in female, all the setae arising immediately from the corresponding segment, without any intervening lamella. Genital lobes closely approximate and of obtusely triangular form, each carrying outside near the end a slender seta. Length of the specimen examined 2.15 mm. Remarks. — Of this peculiar Copepod only the female sex was described in Vol. V. I now add the above short diagnosis of the male, and on PI. XII 20 give figures of the whole animal in dorsal and lateral aspects, and of some of the appendages more highly magnified. Occurrence. — The male specimen here described was kindly sent to me from Dr. Jules Richard. I have myself not met with this Copepod since I observed the solitary female specimen described in Vol. V and taken at Hval0r, outside the Christiania Fjord. Fam. Cerviniidae. Gen. Cerviniopsis, G. O. Sars. 11. Cerviniopsis clavicornis, G. O. Sars. (PI. XIII, fig. 1). Cfr. Vol. V, p. 22, Pj. XII, PI. XIII, fig. 1. specific Characters. — Male. General form of body closely resembling that of female. Rostral plate, however, comparatively larger and more pro- minent, and the 2 anterior caudal segment more sharply marked off from each other. Anterior antennae only slightly transformed, and scarcely at all prehen- sile, being apparently composed of 8 joints, the outer 4 of which, however, are less perfectly defined and together form a thinner terminal part bent back- wards at an angle to the proximal part; 2nd, 3rd, 4th and 6th joints each with a well-developed aesthetask; last joint very small and armed at the tip with a minute claw-like spine accompanied by some unequal setae. Posterior antennae, oral parts, and natatory legs exactly as in the female. Last pair of legs, however, conspicuously transformed, each leg being composed of 3 well- defined joints, the 1st of which, as in female, is quite short and produced outside to a digitiform process carrying a slender seta; middle joint armed at the end outside with a slender spine and about of same size as the terminal one, which carries 5 spines, one outside, 2 inside and 2 on the tip. Genital lobes rather remote, the one from the other, and of very small size, knob-like, each lobe carrying on the tip 2 slender setae. Length of the specimen examined 1.13 mm. Remarks.— 0\ this form also only the female sex has been described in Vol. V. The male, of which I now am enabled to give a diagnosis, is so very like the female in its outward appearance, that it easily may escape 21 ■attention. It is however of somewhat inferior size and moreover, on a closer examination, exhibits some well-marked sexual differences, especially as regards the structure of the anterior antennae and the last pair of legs. The imperfect )rehensile nature of the former appendages is very remarkable. p . Occurrence. — The present peculior Copepod was formerly only known from the Lofoten islands. I have in the latter years taken it rather abun- dantly at Riser, South coast of Norway, in depths ranging from 60 to 100 fathoms, muddy bottom. Among the numerous specimens collected only very few males were detected. Gen. Zosime, Boeck. Remarks. — Two well defined species of this genus, Z. typica Boeck and Z. incrassata G. O. Sars, have been described in Vol. V. In the present Volume 2 other species are added, both of which are closely allied to the typital one, though apparently distinct. 12. Zosime major, G. O. Sars, n. sp. (PI. XIII, fig. 2). Specific Characters. — Female. Very like Z. typiea in its outward appearance, but of considerably larger size and comparatively more slender form of body. Anterior segments of urosome, as in that species, expanded laterally to triangular recurved lamellae finely spinulose at the edges; penultimate segment simple, cylindrical in form, and armed along the hind edge dorsally with a dense and regular row of rather coarse denticles. Caudal rami rather produced, being fully 3 times as long as they are broad, and somewhat con- stricted at the base; anterior half of the outer edge finely spinulose, seta of same edge of moderate size and attached near the end of the ramus; apical setae only 3 in number on each ramus, that usually attached to the outer corner being wholly absent; innermost seta comparatively small, the other 2 rather strong and clothed in their outer part with small prickles instead of the tisual cilia. Antennae, oral parts, and natatory legs of a structure very similar to that in the type species. Last pair of legs, however, differing in the much , larger size of the inner expansion of the proximal joint, which is broadly rounded at the end and provided with 4 strong marginal setae; distal joint comparatively small, but well defined at the base, Colour whitish grey. 22 Length of adult female amounting to 0.70 mm. Remarks.— The present species is closely allied to the typical one, but of considerably larger size and somewhat more slender form of body, differing moreover conspicuously in the more produced caudal rami and in the structure of the last pair of legs. It is very probable, that the form recorded by British authors as Z. iypica Boeck is more properly referable to the present species. Occurrence.— I have met with this form occasionally in 2 different localities on the southern coast of Norway, viz., at Korshavn and Ris0r. It occurred in both places together with the typical species in depths ranging from 20 to 50 fathoms, muddy bottom. Only female specimens have as yet come under my notice. Distribution. — ? British Isles (Brady & Scott). 13. Zosime valida, G. O. Sars, n. sp. (PI. XIV). Specific Caracters. — Female. Body of a more robust and compact form than in the preceding species, with the 2 chief divisions less sharply marked of from each other and nearly of equal length. Rostral plate rather prominent and sub-triangular in form, tip narrowly truncated and carrying the 2 usual sensory hairs. Lateral lobes of the anterior caudal segments far less prominent than in the preceding species; penultimate segment, as in that species, armed along the hind edge dorsally with a row of denticles, which however are much stronger and of a somewhat flattened form. Caudal rami comparatively broad, sub-lamellar, the greatest width considerably exceeding half the length; seta of outer edge remarkably strong and attached to a sharply defined ledge somewhat remote from the end; apical setae present in the usual number, that of the outer corner longer than that of the inner; the 2 middle setae well developed and of quite normal appearance. Anterior antennae apparently composed of 7 joints densely clothed with seta, most of which are coarsely ciliated. Posterior antennae, oral parts, and natatory legs exhibiting the structure characteristic of the genus. Last pair of legs with the distal joint wholly confluent with the proximal one; inner expansion of the latter com- paratively small, and only provided with 2 slender setae, both issuing form the narrowly truncated tip. Colour whitish grey. Length of the specimen examined 0.70 mm, 23 Remarks. — This form also is closely allied to the type species, though easily distinguishable both from it and from the preceding species by the comparatively more compact form of the body, and more particularly by the structure of the caudal rami and of the last pair of legs. Occurrence.— On\y a solitary female specimen of this form has hitherto come under my notice. It was taken last summer at Hval0r, outside the Chri- stiania Fjord, from a depth of about 20 fathoms, muddy bottom. Fam. Ectinosomidae. Gen. Ectinosoma, Boeck. Remarks. — This genus seems to be exceedingly rich in species. To the 13 species described in Vol. V I am now enabled to add 8 more, the number of Norwegian species thus arising to no less than 21 in all. The determination of these species is, however, in some cases not easy on account of the rather uniform outward appearance of the body, and the anatomical examination is moreover rendered rather difficult by the glossy and tough integuments and by the smallness and fragility of some of the appendages. The most reliable distinguishing character is derived from the structure of the last pair of legs, which is perfectly constant and in nearly every case exhibits some peculiarity characteristic of the species. 14. Ectinosoma proximum, G. O. Sars, n. sp. (PI. XV, fig. 1). specific Characters. — Female. Very like E. neglectum G. O. Sars, as to the general form of the body, but of somewhat smaller size. Rostral plate slightly prominent and, as seen dorsally, obtusely truncated at the end. Uro- some somewhat shorter than the anterior division and gradually tapered behind; anal segment scarcely more than half as long as the preceding segment and deeply incised behind in the middle. Caudal rami somewhat divergent, and almost twice as long as they are broad at the base; apical setae of moderate length. Anterior antennae comparatively rather short and stout, being apparently only composed of 5 joints densely clothed with strong curved setae. Posterior antennae, oral parts, and natatory legs exhibiting a structure very similar to 24 that in E. negledum. Last pair of legs, however, differing conspicuously in the shape of the distal joint, the outermost lobe of which is narrow digitiform and defined from the remaining part of the joint by a deep and narrow incision extending almost to the base of the joint; inner expansion of proximal joint comparatively shorter than in E. negledum, extending scarcely beyond the middle of the distal one; marginal setae of both joints coarsely ciliated and rather unequal in length, that issuing from the middle lobe of the distal joint being the longest and extending about to the end of the genital segment. Colour of the living animal not yet ascertained. Length of adult female scarcely exceeding 1 mm. Remarks. — The outward appearance of the present form looks so very like that of E. negledum G. O. Sars, that at first I was inclined to regard it as merely an accidental variety of that species. Having however subsequently obtained several specimens of this form from widely distant localities, and in all of them found the very same characteristic structure of the last pair of legs, I am now of opinion that it more properly ought to be regarded as specific- ally distinct. Occurrence. — I have found this form in 2 widely distant localities on the Norwegian coast, viz., at Bejan, outside the Trondhjem Fjord, and at Risar, in depths ranging from 20 to 50 fathoms. AH the specimens obtained were of the female sex. .15. Ectinosoma angulifrons, G. O. Sars, n. sp. (PI. XV, fig. 2). Specific Characters. — Female. Body comparatively slender, with the anterior division only slightly dilated. Rostral plate not much prominent and, as seen from above, terminating in an acute angle. Urosome much shorter than the anterior division and only slightly tapered behind; anal segment scarcely exceeding half the length of the preceding segment, and slightly incised behind in the middle. Caudal rami small, about as long as they are broad, and somewhat divergent; apical setae of moderate length. Anterior antennae resembhng in structure those in the preceding species, though com- paratively a little more slender. 1st pair of legs with the inner ramus, as usual, much larger than the outer, which scarcely extends beyond the middle joint of the former. Last pair of legs resembling in structure those in E. pro- pinqvum Scott, the distal joint being subquadrangular in form and somewhat unequally trilobed at the end; inner expansion extending beyond the middle Phaennidas Copepoda Suppl. Volume PI. I 6. 0. Sars, del. Xanthocalanus minor, 6iesbrecht. Stephids Copepoda Suppl. Volume PI. II h-^: *■ 6. O. Sars, del. Stephos minor, Scott Stephidae Copepoda SuppI, Volume PI. Ill :i;fa^-i-t|' ~\, i> Nil; *fx \V III 6. O. Sars, del. Parastephos pallidus, 6. O. Sars Pseudocyclopiidae Copepoda Suppl. Volume PI. IV ? y^tJ^^^ 6. O. Sars, del. Pseudocyclopia 6iesbrechti, WIfend. Copepoda Pseudocyclopiidaa Suppl. Volume PI. V 6. O. Sars, del. 1. Pseudocyclopia 6iesbrechti, WIfend. (continued) 2. Pseudocyclopia crassicornis, Scott PlatycopiidaB Copepoda Suppl. Volume a^^^ 5 /^ iTfir-' PI. VI G. O. Sars, del. Platycopia perplexa, 6. O. Sars PlatycopiidsB Copepoda Suppl. Volume PI. VII 6. O. Sars, del. 1. Platycopia perplexa, 6. 0. Sars (continued) 2. Platycopia pygmaea, 6. 0. Sars Pseudocyciopidae Copepoda Suppl. Volume PI. VIII I /. ■* )l ?L a^ OSl', //ifn. /-;,< %. /f 7//)'' 11 •^ I 6. O. Sars, del. Pseudobradya ambigua, 6. O. Sars EctinosomidaB Copepoda Suppl. Volume PI. XXVI 6. O. Sars, det. Bradya Scotti, 6. O. Sars Ectinosomidae Copepoda Suppl. Volume PI. XXVII G. O. Sars, del. 1. Bradya macrochaeta, 6. O. Sars 2. „ furcata, G. O. Sars Ectinosomidae Copepoda Suppl. Volume PI. XXVIII 6. O. Sars, del. 1, Bradya congenera, G. O. Sars 2. „ simulans, 6. O. Sars EctinosomidaB Copepoda Suppl. Volume PI. XXIX .^>f^ ilLMd J-n. 6. O. Sars, del. Halophytophilus spinicornis, 6. O. Sars HarpacticidaB Copepoda Suppl. Volume Pi. XXX III I'H t m. 6. O. Sars, del. Harpacticus tenellus, 6. 0. Sars IdyaeidaB Copepoda Suppl. Volume PI. XXXI I ^ym-^ I G. O. Sars, del. Idyaea graciloides, 6. O. Sars Idyaeidae Copepoda Suppl. Volume PI. XXXII G. O. Sars, del. Idyaea compacta, 6. O. Sars 53 Antennae and oral parts built on the very same type as in the 2 other known species. 1st pair of legs likewise of a very similar structure, the inner ramus being considerably longer than the outer, and only composed of 2 joints very sharply defined from each other, the distal one slightly shorter and much narrower than the proximal one, and armed at the tip with 2 exceedingly slender claw-like spines accompanied inside by a small bristle; inner edge of this joint carrying 2 somewhat larger setae. The 3 succeeding pairs with the basal part rather broad and flattened, rami slender and of nearly equal length. Last pair of legs very narrow, with the proximal joint simple cylindric in shape, not expanded inside, distal joint a little longer than the proximal one, and conically tapered, with 3 small setae on the tip and another somewhat larger seta inside near the base. Colour of the living animal not yet ascertained. Length of adult female 0.58 mm. Remarks. — The above-described form is unquestionably referable to the genus Idyella, as defined by the present author, exhibiting, as it does, a struc- ture of the several appendages very similar to that found in the 2 other known species. It is however of considerably larger size than either of them and also of a comparatively more robust form of the body. Occurrence.— k solitary female specimen only of this form has as yet come under my n.otice. It was found in a sample taken some years ago out- side Christiansand from a depth of about 30 fathoms. 42. Idyella exigua, G. O. Sars. See Vol. V, p. 101, Pi. LVIII, fig. 2. (PI. XXXIII, fig. 2). Remarks. — The female of this species has been described and figured in Vol. V from some specimens taken at Bukken, south west coast of Norway. I have subsequently found this form not unfrequently in several places on the south coast, Korshavn, Lillesand, Riser, in depths ranging from 20 to 60 fathoms. Male specimens are very rarely met with, and may also easily escape attention on account of their small size. On the accompanying plate I have given some detail-figures of such a specimen, elucidating the rather well-marked sexual differences in the structure of the anterior antennae and the 2nd and last pairs of legs. 8 — Crustacea. 54 Gen. Idyanthe, G. O. Sars. Remarks.— This name was proposed by the present author in 1909, to replace Idyopsls, the latter name having been preoccupied. 43. Idyanthe dilataia, G. O. Sars. See Vol. V, p. 98, PI. LVII, fig. 1. (PI. XXXIII. fig. 3). Remarks. — Of this form also only the female sex has been described. The male, of which a solitary specimen was obtained at Riser, differs from the female in a much similar manner to that found in Idyel/a. On the accom- panying plate the inner ramus of a leg of the 2nd pair from this male specimen is figured. Fam. Diosaccidae. Gen. Stenheliopsis, G. O. Sars. Remarks. — Three well-defined species of this genus have been recorded in Vol. V, and a 4th species, nearly allied to the typical one, is now added, and will be described below. 44. Stenheliopsis affinis, G. O. Sars, n. sp. (PI. XXXIV). Specific Characters. — Female. General form of body resembling that in 5. divaricaia, being comparatively rather short and stout, with the anterior division considerably broader than the posterior. Cephalic segment large and evenly rounded in front; rostral plate prominent, linguiform, blunted at the tip. Urosome about the length of the anterior division and quite smooth. Caudal rami still more abruptly divergent than in the type species, but comparatively less slender, scarcely exceeding in length the last 2 caudal segments combined, each ramus armed at the somewhat thickened base with a transverse row of small denticles; innermost but one of the apical setae very strong and closely annulated in the middle, curving abruptly outwards and forwards in a sigmoid 55 manner and crossing the neighbouring seta at some distance from its base. Anterior antennas composed of 5 joints, the first 2 of which are much the largest, outer part of the antenna, as in the type species, abruptly recurved and densely clothed with strong curved setae. Posterior antennae and oral parts built on the same type as in S. divarlcata. Natatory legs likewise rather similar in structure, the inner ramus being in all of them only composed of 2 joints. Last pair of legs resembling in shape those in the type species, though having the inner expansion more distinctly defined and the marginal setae considerably longer. Ovisacs small, each containing only a single ovum. Colour whitish. Length of adult female 0.63 mm. Remarks. — The present form is closely allied to the type species, S. divaricata G. O. Sars, but of somewhat larger size, differing moreover in the comparatively less slender caudal rami, as also somewhat in the structure of the anterior antennae and the last pair of legs. Occurrence. — Some specimens of this form, all of the female sex, were found at Risor in depths ranging from 30 to 50 fathoms, muddy bottom. Fam. Canthocamptidae. Gen. Attheyella, Brady. 45. Attheyella Schmeili, (Mrazek). (PI. XXXV). Canthocamplus Schmeilii, Mrazek, Beitrag zur Kenntniss der Harpacticidenfauna des Siisswassers. Zool. Jahrb. Vol. 7, p. 116, PI. 7, figs. 107-117. Specific Characters. — Female. Body comparatively slender and only slightly tapered behind, with all the segments distinctly denticulated along the hind edge dorsally. Cephalic segment about the length of the 3 succeeding segments combined, and broadly rounded in front, without any distinctly defined rostral projection. Urosome almost as long as the anterior division; genital segment somewhat shorter than the 2 succeeding segments combined; last segment well developed and of about same size as the preceding segment; anal opercle only slightly prominent, and obtusely truncated at the end, with the edge very finely denticulated. Caudal rami comparatively large, exceeding 56 somewhat in length the anal segment, and obpyriform in outline, being rather broad at the base and gradually tapered distally, inner edge considerably bulged at the base and, like the outer, coarsely ciliated; seta of outer edge attached far in front; dorsal seta well developed and issuing a little farther behind; apex provided with only a single well-developed seta flanked by 2 small bristles. Anterior antennae a little shorter than the cephalic segment, with the joints rather sharply marked off from each other, terminal part a little shorter than the proximal one. Posterior antennae with the outer ramus comparatively small, though distinctly biarticulate, distal joint short, carrying on the tip a stout spine and a short seta. Mandibles with the palp very small, uniarticulate, with 2 apical setae. Maxillae and maxillipeds of normal structure. 1st pair of legs with the inner ramus considerably longer than the outer, though only composed of 2 joints; middle joint of outer ramus wanting the usual seta inside. The 3 succeeding pairs of legs having the outer ramus rather strongly built, with the spines very coarse; inner ramus, as usual, poorly developed, biarticulate, with the distal joint very narrow and only carrying a single apical seta. Last pair of legs of moderate size, with the distal joint oval in form and edged with 5 setae, the middle one small and not ciliated; inner expansion of proximal joint narrow linguiform and not extending as far as the distal joint, marginal setae 5 in number. Male smaller than female and exhibiting the usual sexual differences, being moreover distinguished by the much smaller size of the caudal rami. Inner ramus of 2nd pair of legs comparatively larger than in female, extending about to the middle of the terminal joint of the outer; that of 3rd pair trans- formed in the usual manner, being distinctly 3-articulate, with the middle joint produced at the end outside to a strong mucroniform process. 4th pair of legs with the spine attached to the middle joint of the outer ramus very strong and somewhat twisted; inner ramus very small and tipped with a strong spiniform seta and a much smaller bristle. Last pair of legs, as usual, much reduced in size. Colour witish gray, with a faint yellow tinge. Length of adult female 0.63 mm. Remarks. — This form, first described by Mrazek as a species of Can- thocamptus, ought evidently to be referred to the present genus, as defined in Vol. V. It is easily recognised by the comparatively large size of the caudal rami, which however, unlike what is generally the case, exhibit a somewhat different appearance in the two sexes. 57 Occurrence. — Like the other known species of the present genus, this form is exclusively an inhabitant of fresh water. The only locality where I as yet have met with it, is the lake Vansje near Moss. It occurred here occasion- ally, together with Moraria brevipes G. O. Sars, in a depth of 3 — 6 fathoms, muddy bottom. Distribution.— Bohemia (Mrazek), British Isles (Scott), Sweden (Lilljeborg). Gen. Ameira, Boeck. 46. Ameira dubia, G. O. Sars, n. sp. (PI. XXXVI). Specific Characters.— -Female. Body comparatively slender, with the anterior division conspicuously dilated in its anterior part. Cephalic segment large, equalling tn length the 3 succeeding segments combined, frontal edge slightly angular, but without any distinctly defined rostrum. Urosome rather narrow, equalling in length about Vi of the anterior division; genital segment longer than the 2 succeeding segments combined; last segment fully as large as the preceding one. Caudal rami short, being only slightly longer than they are broad, and somewhat divergent; apical setae well developed. Anterior antennae fully as long as the cephalic segment and distinctly 8-articulate, ter- minal part exceeding half the length of the proximale one. Posterior antennae and oral parts of normal structure. 1st pair of legs imperfectly prehensile, the inner ramus being only slightly longer than the outer, with the 1st joint scarcely longer than the other 2 combined. The 3 succeeding pairs of legs of normal appearance, except that the terminal joint of the outer ramus in the 3rd and 4th pairs has inside 3, instead of 2 setae. Last pair of legs with the distal joint rather narrow, oblong in form, and somewhat constricted at the base, marginal setae 6 in number; inner expansion of proximal joint comparatively large, broadly linguiform, and extending beyond the middle of the distal joint; marginal setae rather strong and 5 in number. Colour not yet ascertained. Length of adult female 0.90 mm. Remarks. — This is a somewhat anomalous form, differing from the more typical species of the present genus by the imperfectly prebensile cha- racter of the 1st pair of legs and the greater number of setae on some of the succeeding pairs. In these respects it agrees with the aberrant species, A. simplex Scott, and should perhaps, together with this species, be included in a 58 particular genus intermediate between Ameira and Parameira. It is of rather large size, as compared with the other known species. Occurrence. — Two female specimens of the present form were found in a sample taken at Riser from a depth of about 30 fathoms. 47. Ameira exilis, Scott. (PL XXXVII). Ameira exilis. Scott, Twelfth Ann. Report of the Fishery Board for Scotland, Part III, p. 242, PI. X, figs. 1-12. Specific Characters.- Male. Body exceedingly slender and narrow, linear in form, with the anterior division scarcely broader than the posterior. Cephalic segment about the length of the 2 succeeding segments combined and obtusely blunted in front, rostral projection inconspicuous. Urosome fully as long as the anterior division, with the segments subequal in size and almost perfectly smooth. Caudal rami comparatively short, being scarcely more than half as long as the anal segment; apical setae of moderate length. Anterior antennae about the length of the first 2 body-segments combined, and very conspicuously hinged, the middle portion being considerably dilated; terminal part composed of 3 elongated joints, the last clothed with long curved setae. Posterior antennae with the outer ramus biarticulate, distal joint however very small and less distinctly defined at the base. Mandibles with the palp of unusual size, its proximal joint forming inside a broad lamellar expansion armed with 3 strong, spiniform setae; distal joint narrow, sublinear in form. Maxillae and maxillipeds of normal structure. 1st pair of legs distinctly prehen- sile, the inner ramus being much longer than the outer, with the last 2 joints bent inwards, and combined about the length of the 1st joint; middle joint of outer ramus with a well-defined seta inside, wanting in the other known species; spine issuing from the inner corner of the 2nd basal joint very strong and sub-hamate 'at the tip. The 3 succeeding pairs of legs of normal structure and rather slender, especially the 4th paii, the outer ramus of which is fully twice as long as the inner. Last pair of legs more fully developed than is generally the case in male specimens; distal joint oval in form and provided with 6 marginal setae, 4 of which issue from the obtusely blunted end, one of the latter (the innermost but one) very much elongated; inner expansion of proximal joint well developed and rather prominent, extending about to the middle of the distal joint, marginal setae 5 in number, the outermost but one the longest, 59 Colour whitish, pellucid. Length of the specimen examined 1.12 mm. Remarks. —The above described form is evidently referable to the large species recorded by Scott as A. exilis and observed by that author in both sexes. Mr. Scott states the length of the adult female to be no less than 1.40 mm., and the present form accordingly grows to a size far exceeding that in any ot the other known species of Ameira. Occurrence. — A solitary male specimen only of this form has as yet come under my notice. It was captured at Ris0r from a depth of about 20 fathoms. Distribution. — Scottish coast (Scott). Gen. Parameira, G. O. Sars. Remarks. — Of this genus 4 well-defined species have been recorded by the present author, 3 from the Norwegian coast and one from the Polar Islands North of Grinnels Land (2nd Fram Expedition). Two additional species, both of which have been previously observed by Scott, will be described below. 48. Parameira longiremis, (Scott). (PI. XXXVIII, fig. 1). Ameira longiremis, Scott, Twelfth Annual Report of the Fishery Board for Scotland, Part 111, p. 241, PI. V, figs. 29—32; PI. VI, figs. 1-5. Specific Characters. —Female. Body comparatively short and robust, with the 2 chief divisions rather sharply marked off from each other. Cephalic segment about the length of the 2 succeeding segments combined and evenly rounded in front, rostral projection inconspicuous. Urosome much shorter than the anterior division and almost of equal width throughout; genital segment large, exceeding somewhat in length the 2 succeeding segments com- bined; last segment scarcely shorter than the preceding one, with the anal opercle considerably prominent and narrowly rounded at the end. Caudal rami very small and remote from each other; apical setae of moderate length. An- terior antennae comparatively short and stout, not attaining the length of the cephalic segment, 2nd joint only slightly longer than it is broad. Posterior antennae with the outer ramus very small, uniarticulate, carrying 2 short setae, the one apical, the other lateral. Oral parts normal. 1st pair of legs with the inner ramus considerably longer than the outer, its 1st joint rather dilated _60_ and about the length of the terminal joint, middle joint comparatively short. The 3 succeeding pairs of legs exhibiting the structure characteristic of the genus. Last pair of legs with the distal joint exceedingly slender and narrow, sublinear in form, being fully 5 times as long as it is broad, and clothed on both edges with scattered hairs; marginal setae 5 in number, all issuing from the end of the joint; iimer expansion of proximal joint triangular in form and carrying 5 strong setae. ^ Colour not yet ascertained. Length of adult female 0.58 mm. Remarks. — Though rather inferior in size, the above-described form agress pretty well with the description and figures given by Scott of his Ameira longiremis, and its identity with that species seems to me therefore to be beyond doubt. It is unquestionably referable to the genus Pammeira, as defined by the present author, and may be recognised from the other species of that genus by the comparatively robust form of the body, and more par- ticularly by the very slender and narrow distal joint of the last pair of legs. Occurrence. — Some few specimens of this form, all of the female sex, were picked up from samples taken at Korshavn in depths ranging from 30 to 50 fathoms, muddy sand. 49. Parameira intermedia, (Scott). (PI. XXXVIII, fig. 2). Ameira longiremis, var. intermedia, Scott, Twelfth Annual Report of tlie Fishery Board for Scotland, Part 111, p. 242, PI. VI, figs. 6-14. Specific Characters,— Female. Body considerably more slender than in the preceding species, with the anterior and posterior divisions of nearly equal length. Last caudal segment a little shorter than the proceding one, with the anal opercle less prominent and evenly rounded at the end. Caudal rami a little longer than they are broad; apical setae of moderate length. Anterior antennae comparatively shorter than in the preceding species, other- wise of a very similar structure. * Posterior antennae with the outer ramus, as in that species, very small, uniarticulate, but rather narrower, with both setae issuing from the end. 1st pair of legs resembling in structure those in P. longiremis, inner ramus however comparatively shorter, with all 3 joints of about equal length. Last pair of legs with the distal joint not nearly so elongated as in the preceeing species and oblong oval in form; inner expansion 61 of proximal joint extending about to the middle of the distal joint, and having the marginal setae less unequal in length than in the preceding species. Colour not yet ascertained. Length of adult female 0.62 mm. Remarks. — The present form is considered by Scott to be only a variety of the preceding species. I think however that the differences indicated in the above diagnosis may suffice for warranting its specific distinctness. Occurrence. — Of this species also only a small number of specimens have as yet come under my notice. They were obtained from the same samples as the preceding species. Distribution. — Scottish coast (Scott). Gen. Pseudameira, G. O. Sars. Remarks. — This genus was established by the present author in the year 1911, to comprise 2 well defined species, both obtained at Korshavn. I am now enabled to add 2 new species of this genus from another locality of the Norwegian coast. 50. Pseudameira gracilis, G. O. Sars, n. sp. (PI. XXXIX). Specific Characters. — Female. Body much more slender and elongated than in either of the 2 previously described species, with the anterior division only slightly broader than the posterior. Cephalic segment equalling in length the 3 succeeding segments combined and rounded in front; rostral prominence small, but well defined, acuminate. Urosome about the length of the anterior division and nearly smooth; genital segment comparatively large, equalling in length the 3 succeeding segments combined, and distinctly subdivided in the middle; last segment much shorter than the preceding one. Caudal rami con- siderably produced, equalling in length the last 2 caudal segments combined, and narrow linear in form; apical setae not much elongated. Anterior antennae short and stout, not nearly attaining the length of the cephalic segment, but composed of 8 well defined joints, the 2nd of which is the largest and of rounded oval form, with the outer edge arcuate and clothed with stiff hairs; terminal part, comprising the 4 outer joints, short, scarcely exceeding the 2 preceding joints combined, and clothed with long curved setae. Posterior 9 — Crustacea. 62 antennae with ttie outer ramus very narrow, bisetose. Oral parts normal. 1st pair of legs with the inner ramus scarcely longer than the outer, its terminal joint somewhat exceeding the middle one in length. The 3 succeeding pairs of legs comparatively strongly built, and resembling somewhat in structure those in P. fiircata, the inner ramus being rather produced and extending beyond the outer, its 1st joint rather dilated and, as in P. fureata, armed inside near the base with a strong spine, replacing the usual seta, inner edge of the joint beyond the spine densely spinulose; middle joint produced at the end inside to a well developed spiniform process. 2nd basal joint of these legs armed inside with 4—5 coarse denticles. Last pair of legs of comparatively small size; distal joint oval quadrangular in form and remarkably constricted at the base, inner edge bulging and fringed with long cilia; marginal setae 5 in number, the 2 innermost ones rather slender; inner expansion of proximal joint short and broad, with 5 marginal setae. Male, as usual, smaller than female and easily recognisable by the distinctly hinged anterior antenna; none of the legs transformed. Colour whitish. Length of adult female 0.75 mm. Remarks. — The present form is nearly allied to P. fiircaia, but of considerably larger size, and moreover at once distinguished by the much more slender and elongated form of the body. It also exhibits some well-marked differences in the structural details, as indicated in the above diagnosis. Occurrence.— I have found this form not unfrequently at Ris0r in depths ranging from 30 to 60 fathoms, muddy sand. 51. Pseudameira mixta, G. O. Sars, n. sp. (PI. XL). Specific Characters.— Female. Body of a similar slender form to that of the preceding species, with the anterior division only slightly broader than the posterior. Rostral prominence well marked, but very small, acute. Urosome nearly as long as the anterior division, its last segment of about same size as the preceding one. Caudal rami less produced than in the preceding species, being scarcely longer than the anal segment; apical setse rather slender. Ante- rior antennae still shorter than in the said species and only composed of 6 joints, 2nd joint with the outer edge perfectly smooth. Posterior antennae with the outer ramus slightly widening distally and carrying 3 setae, 2 apical and one lateral. 1st pair of legs with the inner ramus distinctly longer than the 63 outer, its joints of about equal length. The 3 succeeding pairs of legs rather slender, with the inner ramus longer than the outer (at least in 2nd and 3rd pairs), its 1st joint moderately dilated, with the seta of the inner edge very small, not spiniform, and attached beyond the middle, being accompanied behind by a number of thin spinules; 2nd joint not produced at the end inside. Last pair of legs with the distal joint comparatively small, rounded oval in form, and only provided with 4 marginal setae; inner expansion of proximal joint more produced than in the preceding species, extending almost as far as the distal joint, and obtusely truncated at the end, marginal setae 4 in number. Colour whitish^. Length of adult female 0.60 mm. Remarks.— The present form looks rather like P. gracilis in its out- ward appearance, but is of much smaller size, and moreover at once distinguished by the comparatively less produced caudal rami. In the structure of the several appendages it exhibits a somewhat mixed character; hence the specific name here proposed. Occurrence. — Only very few specimens of this form have as yet come under my notice. They were taken at Ris0r from a depth of about 50 fathoms, muddy bottom. Gen. Stenocopia, G. O. Sars. Remarks.— Ihe type of this genus is the form described by Scott as Amelra longlcaudata, which however, as pointed out by the present author, must be discarded from the genus Amelra, as defined by Boeek. Two other well- defined species of the present genus have been recorded in Vol. V, and I now am enabled to add another species, to be described below. 52. Stenocopia minor, G. O. Sars, n. sp. (PI. XLI). Specific Characters. — Female. Body comparatively less slender than in the type species, with the anterior division slightly broader than the posterior. Cephalic segment about the length of the 3 succeeding segments combined, and projecting in front to a triangular rostral plate. Trunkal segments per- fectly smooth. Urosome (including the caudal rami) fully as long as the anterior division and only slightly tapered behind, its segments minutely denti- culate at the hind edge; genital segment of moderate size and imperfectly 64 subdivided in the middle; last segment considerably larger than the preceding one, with the anal opercle somewhat prominent and broadly rounded at the end. Caudal rami slender and narrow, though less elongated than in the other known species, scarcely exceeding in length the anal segment; apical setae moderately slender. Anterior antennae rather narrow, exceeding somewhat in length the cephalic segment, and composed of 9 well defined joints clothed with comparatively long curved setae; 2nd joint the largest and about equalling in length the 2 succeeding joints combined; penultimate and antepenultimate jonts very small, but distinctly defined. Posterior antennae with the outer ramus narrow, biartieulate, and only provided with 2 setae. Oral parts agreeing in structure with those in the other species. 1st pair of legs with the inner ramus very slender, being fully twice as long as the outer; terminal joint of the latter only armed with 4 spiniform setae. The 3 succeeding pairs of legs exhibiting the slender form characteristic of the genus; inner ramus however com- paratively shorter than in the other species, with the terminal joint less pro- duced and the number of setae somewhat reduced. Last pair of legs with the distal joint narrow oblong in form, and less exserted at the tip than in the other species; marginal setae rather unequal in length and 5 in number; inner expansion of proximal joint comparatively broad, but only very slightly pro- duced, and edged with 4 seta, the outermost one very small. Colour whitish grey. Length of abult female 0.70 mm. Remarks. — The present form is nearly allied to the type species, S. longicaudata (Scott), but is rather inferior in size, and moreover at once distinguished from that species by the comparatively less elongated caudal rami. In the structural details also some well-marked differences are found, as indi- cated in the above diagnosis. Occurrence.— Somt few female specimen of this form were taken at Ris0r from a depth of about 50 fathoms, muddy bottom. Gen. Cletomesochra, G. O. Sars, n. Generic Characters. — Body as a rule short and stout, with the anterior division more or less dilated. Cephalic segment of moderate size, and provided in front with a prominent triangular rostral plate defined behind by a well- marked transverse suture. Caudal rami small and widely apart. Anterior antennae comparatively short and stout, being only composed of 5 joints partly 65 clothed with pectinate setse, last joint large, conically produced at the end. Posterior antennae with the outer ramus distinctly biarticulate. Mandibular palp likewise biarticulate, with the outer ramus small or wanting. Maxillae with the exopodal lobe well defined, bisetose. 1st pair of legs with both rami 3-articulate, the inner one imperfectly prehensile, being far less produced than in Mesochra, and scarcely bent at the end; middle joint of outer ramus without any seta inside. The succeeding pairs of legs comparatively slender, with the outer ramus much longer than the inner, which is only composed of 2 joints. Last pair of legs with the distal joint more or less produced; inner expansion well developed. Remarks. — This new genus is established to include the form described in Vol. V, p. 395, as Mesochra exigua. The rather aberrant characters of this small species were noted in that plase, and it was therefore only with some doubt referred to the genus Mesochra of Boeck. Having now had an oppor- tunity of examining some other forms agreeing pretty well in the more general characters with the above-mentioned species, I think that the establishment of the present genus may be fully justified. The most conspicuous differences from Mesochra are found in the structure of the anterior antennae and in that of the 1st pair of legs. The generic name here proposed alludes to the agreement in structure of the anterior antennae to those in some of the Cleto- didce. 3 new species referable to the present genus will be descritred below. 53. Cletomesochra major, G. O. Sars, n. sp. (PI. XLII). Specific Characters. — Female. Body comparatively more slender than in the type species, with the anterior division only slightly broader than the posterior. Cephalic segment about the length of the 3 succeeding segments combined; rostral plate rather prominent and narrowly truncated at the tip. Urosome shorter than the anterior division and only very slightly tapered behind, its segments minutely denticulate at the hind edge; genital segment not fully attaining the length of the 2 succeding segments combined; last segment nearly as large as the preceding one, with the anal opercle broadly rounded and perfectly smooth. Caudal rami very small, quadrangular in form, with the apical setae comparatively short. Anterior antennae scarcely exceeding half the length of the cephalic segment; the first 3 joints rather thick and gradually somewhat diminishing in size, the other 2, representing the terminal part of the antenna, very unequal in size, the proximal one being quite short, 66 the distal one large and conically produced at the end. Posterior antennae with the basal part not subdivided, outer ramus provided with 4 setae, 2 apical and 2 lateral. Mandibular palp comparatively small, with the proximal joint not expanded and without any trace of an outer ramus. 1st pair of legs with the inner ramus only slightly longer than the outer, and having all 3 joints of about equal length; terminal joint of outer ramus with only 2 spines and 2 geniculated setae. The 3 succeeding pairs of legs agreeing in structure with those in the type species. Last pair of legs with the distal joint of com- paratively smaller size, oblong oval in form, and having the edges nearly smooth, marginal setae 5 in number; inner expansion of proximal joint rather broad and obtusely truncated at the end, extending beyond the middle of the distal joint; marginal setae rather strong and successively increasing in length outwards. Colour whitish grey. Length of adult female 0.57 mm. . Remarks. — The present species is unquestionably congeneric with C. exigua, but of considerably larger size and somewhat more slender form of the body, differing moreover somewhat in the structure of the 1st and last pairs of legs, as also in the less perfectly developed mandibular palp. Occurrence. — A solitary female specimen of this form was obtained last summer (1918) at Hvalor, outside the Christiania Fjord, from a depth of about 6 fathoms. _^ 54. Cletomesochra nana, G. O. Sars, n. sp. (PI. XLIII). Specific Characters.— Female. Body short and stout, resembling in shape that in the type species. Rostral plate somewhat less prominent than in C. major, but of a very similar form. Urosome much shorter than the anterior division, and of about equal width throughout. Caudal rami small, quadrangular in form, with the inner corner somewhat prominent. Anterior antennae almost exactly of same appearance as in the preceding species. Posterior antennae with the outer ramus slightly widening distally and carrying 5 setae, 3 apical and 2 lateral. Mandibular palp with the basal part rather narrow, but having outside a well-marked small joint tipped with a ciliated seta and representing the rudimentary outer ramus. 1st pair of legs with the inner ramus distinctly longer than the outer, its middle joint shorter than either of the other 2, which are of about equal length. The 3 succeeding pairs of _J7^ legs exceedingly slender, with the terminal joint of outer ramus narrower than in the preceding species and almost as long at the other 2 combined. Last pair of legs with the distal joint narrow oblong in form and slightly tapered towards the end, 2 of the outer-edge setae attached near the base of the joint at some distance from the 3 other setae; inner expansion of proximal joint short and broad, transversely truncated at the end, and scarcely extending beyond the middle of the distal joint; marginal setae rather slender, the outermost one the longest. Colour not yet ascertained. Length of adult female 0.41 mm. Remarks. — This form is still more closely allied to the type species, and may on the first sight easily be confounded with it. It is however of smaller size and, on a closer examination, exhibits also some well-marked differences in the structural details, as indicated in the above diagnosis. Occurrence. — Some few female specimens of this dwarfed species were picked up from samples taken at Risor in depths ranging from 30 to 50 fathoms. 55. Cletomesochra rostrata, G. O. Sars, n. sp. (PI. XLIV). Specific Characters.— Female. Body moderately slender, with the an- terior division conspicuously broader than the posterior. Cephalic segment comparatively large, occupying more than half the length of the anterior division; rostral plate greatly prominent and acutely produced at the end. Urosome somewhat shorter than the anterior division, with the segments rather sharply marked off from each other and distinctly spinulose at the hind edge; last segment of about same size as the preceding one and somewhat widening distally; anal opercle finely denticulate at the edge. Caudal rami oblong quadrangular in form, being somewhat longer than they are broad; apical setae rather slender. Anterior antennae of somewhat larger size than in the other species, though not nearly as long as the cephalic segment, 3rd joint remarkably produced at the end anteriorly. Posterior antennae with the outer ramus of moderate size and carrying 4 setae, 2 apical and 2 lateral. Mandi- bular palp with the basal part somewhat dilated and carrying outside a distinctly developed outer ramus. 1st pair of legs with the inner ramus slightly longer than the outer; terminal joint of the latter with 3 outer-edge spines. The 3 succeeding pairs of legs exceedingly slender, with the terminal joint of both rami narrow linear in form. Last pair of legs rather unlike those in the other species, distal joint narrow linear in form, with the 2 outermost setae much 68 longer than the other 3; inner expansion of proximal joint narrowly produced at the end and extending about to the middle of the distal joint; marginal setae only 4 in number. Colour not yet ascertained. Length of adult female 0.67 mm. Remarks. — This is a very distinct and easily recognisable form, differ- ing conspicuously from the other species both in the outward appearance and in the structure of some of the appendages, though, according to the structure of the antennae and of the 1st pair of legs, apparently referable to the present genus. Occurrence.— k solitary female specimen of this form was found in a sample taken at Risor from a depth of about 50 fathoms. Gen. Hemimesochra, G. O. Sars, n. Generic Characters.— Body sub-clavate in form, being conspicuously tumefied in its anterior part and attenuated behind. Rostral plate small and deflexed, not sharply defined behind. Segments of urosome coarsely spinulose at the hind edge. Caudal rami of moderate size. Anterior antennae short and stout, 5-articulate, with some of the setae on the proximal part coarsely pectinate, last joint comparatively large, but not conically produced at the end and with some of the setae ciliated. Posterior antennae with the outer ramus very small, uniarticulate. Mandibles very strong, with the cutting edge imperfectly dentate; palp well developed, but without any distinctly defined outer ramus. Maxillae with the exopodal lobe obsolete. 1st pair of legs not prehensile, the inner ramus being very short and only composed of 2 joints. The 3 succeeding pairs of legs of a structure similar to that in Mesochra. Last pair of legs likewise built on the same type as in that genus, the distal joint being very small, not produced at the end. Remarks.— This new genus is only founded on a single species, which however exhibits certain peculiarities in the structural details forbiding its reception into any of the known genera of the present family, though in some respects it would seem to approch somewhat the genus Cletomesochra. 69 56. Hemimesochra clavularis, G. O. Sars, n. sp. (PI. XLV). Specific Characters.— Female. Body moderately slender, with the anterior division conspicuously inflated in front, almost clavate in form. Cepha- lic segment large and tumid, evenly rounded in front, with the rostral plate abruptly deflexed, so as not being visible in the dorsal view of the animal. Urosome comparatively narrow and somewhat shorter than the anterior division, with the segments sharply marked off from each other and distinctly spinulose at the hind edge, the spinules being arranged in small groups; last segment nearly as large as the preceding one, and having the anal opercle small and perfectly smooth. Caudal rami about the length of the anal segment and somewhat divergent, edges partly spinulose; apical setae of moderate length. Anterior antennae scarcely half as long as the cephalic segment, with the first 2 joints comparatively short and combined scarcely longer than the 3rd; last joint rather large and clothed with long and slender setae. Posterior antennae with the basal part distinctly subdivided, outer ramus carrying 3 setae, 2 apical and one lateral. Mandibular palp with the basal joint rather large, though not much expanded, and provided in the middle of the outer edge with a strong ciliated seta replacing the outer ramus. 1st pair of legs much smaller than the succeeding pairs, with the inner ramus scarcely extending beyond the middle of the terminal joint of the outer, its proximal joint somewhat expanded and carrying inside the usual ciliated seta, distal joint of about same length, but much narrower, and armed at the tip with a strong spine accompanied inside by 2 unequal setae; outer ramus without any setae inside, terminal joint with only 2 outer-edge spines. The 3 succeeding pairs of legs well developed, with the inner ramus somewhat exceeding half the length of the outer and resembling in shape that in Mesochra. Last pair of legs with the distal joint very small, sub-quadrangular in form, and only provided ivith 4 setae, the innermost of which is much elongated, the other 3 com- paratively short; inner expansion of proximal joint extending far beyond the distal joint and obtusely truncated at the end; marginal setae 4 in number and of very unequal length, the outermost but one much the largest. Colour not yet ascertained. Length of adult female 0.53 mm. Remarks. — The present form may be easily recognised from any of the other known Canthocamptidce by the peculiar clavate shape of the body, a character which has given rise to the specific name here proposed. 10 — Crustacea. 70 Occurrence. — Two female specimens only of this peculiar form iiave as yet come under my notice. They were taken at Riser from a depth of about 50 fathoms, muddy bottom. Fam. Laophontidae. Gen. Laophonte, Philippi. 57. Laophonte brevifurca, G. O. Sars, n. sp. (PI. XLVI). Specific Characters. — Female. Body moderately slender and slightly attenuated behind, with all the segments well marked off from each other. Cephalic segment nearly half the length of the anterior division; rostral pro- minence comparatively short, triangular, and obtusely pointed at the end. Urosome shorter than the anterior division, and having the lateral expansions of the anterior segments well marked and densely spinulose at the edge; last segment about twice as broad as it is long, anal opercle rounded and distinctly denticulate at the edge. Caudal rami very short, being scarcely longer than they are broad dt the base; apical setae of moderate length. Anterior antennae comparatively short and only composed of 6 joints, the last 2 being con- fluent; 2nd joint rather broad, of rounded form, and without any projection of the outer edge. Posterior antennae and oral parts of normal structure. 1st pair of legs less strongly developed than usual, with the outer ramus distinctly 3-articulate and extending beyond the middle of the proximal joint of the inner. The 3 succeeding pairs of legs with the inner ramus scarcely half as long as the outer, and only provided with 3 setae at the end. Last pair of legs with the distal joint comparatively small, narrow sub-quadrangular in form, and carrying 5 marginal setae, all issuing from the nearly transversely trun- cated end, one of the setae (the innermost but one) much longer than the others; inner expansion of proximal joint rather produced, extending almost as far as the distal joint; marginal setae 4 in number. Colour whitish grey, with a faint yellow tinge. Length of adult female 0.70 mm. Remarks. — The above-described form, though not exhibiting any more prominent peculiarity in its structure, does not agree fully with any of the 71 numerous species of the present genus as yet known. It may be best recognised by the very small size of the caudal rami, a character which indeed has given rise to the specific name here proposed. Occurrence. — A solitary female specimen of this form was found last summer (1918) at Hval0r, outside the Christiania Fjord, in a depth of about 6 fathoms. 58. Laophonte tenera, G. O. Sars, n. sp. (PI. XLVII). Specific Characters. — Female. — Body rather slender and narrow, rapidly tapered behind, with the segments sharply marked off from each other. Cephalic segment large and tumid, occupying fully half the length of the anterior division; its postero-lateral corners produced in a peculiar manner and curved upwards; rostral projection rather prominent, triangular, and minu- tely bilobular at the tip. Urosome almost as long as the anterior division, and having the lateral expansions of the segments rather prominent and densely spinulose at the edges; last segment scarcely broader than it is long and slightly widening distally, anal opercle finely denticulate at the edge. Caudal rami about twice as long as they are broad and considerably divergent ; apical setae of moderate length. Anterior antennae more slender than in the preceding species, though not nearly attaining the length of the cephalic segment, and composed of 7 well defined joints; 2nd joint the largest and oblong oval in form, with a very small prominence of the outer margin. Posterior maxillipeds comparatively larger than in the preceding species. 1st pair of legs likewise more powerfully developed; outer ramus however rather small, not extending to the middle of the proximal joint of the outer, and only composed of 2 joints. The 3 succeeding pairs of legs of normal structure. Last pair of, legs with the distal joint well developed, broadly spatulate in form, and provided with 5 marginal setae, the innermost but one the longest and issuing from a digitiform process of the joint; inner expansion of proximal joint short and broad, obtusely rounded, and not extending to the middle of the distal joint; marginal setae 4 in number. Male of smaller size than female and having the anterior antennae very strongly hinged. 2nd pair of legs with one of the setae attached to the distal joint of the inner ramus transformed in a similar manner to that found in L. brevirostris and allied species. 3rd pair of legs, as usual, much more strongly built than in female, with the inner ramus distinctly 3-articulate and 72 having the middle joint acutely produced at the end outside. Last pair of legs' much reduced in size, distal joint rather narrow and only provided with 4 setae; inner expansion of proximal joint obsolete. Colour not yet ascertained. Length of adult female 0.60 mm. Remarks. — This form seems to be nearest allied to L. macera G. O. Sars, but is of somewhat larger size, and moreover at once distinguished by the less elongated caudal rami. The shape of the last pair of legs is also rather different. Occurrence. Several specimens of this form, both males and females, were picked up from samples taken at Korshavn at depths ranging from 30 to 50 fathoms. 59. Laophonte abbreviaia, G. O. Sars, n. sp. (PI. XL VIII). Specific Characters. — Female. Body quite unusualy short and stout, and pronouncedly depressed in its anterior part. Cephalic segment of very large size, far exceeding in length the remaining part of the trunk, being broadest behind and gradually somewhat contracted in front; rostral projection rather prominent and somewhat blunted at the end, which appears slightly bilobular. Urosome somewhat tapered behind, and about the length of the cephalic segment; lateral expansions of the segments comparatively small, but well difined and densely spinulose at the edges; last segment, as usual, not expanded and about twice as broad at it is long; anal opercle distinctly denticulate at the edge. Caudal rami of moderate size, about the length of the anal segment, and somewhat divergent; apical setae rather slender. Anterior antennae moderately long and composed of 7 well defined joints, the 2nd of which is the largest and oval in form, without any distinct projection of the outer edge. Posterior antennae with the outer ramus normally developed, somewhat widening distally and provided with 4 subequal ciliated setae. Posterior maxillipeds rather powerful. 1st pair of legs likewise comparatively strongly built, with the outer ramus distinctly 3-articulate, and extending consideratly beyond the middle of the proximal joint of the inner. The 3 succeeding pairs of legs of normal structure. Last pair of legs, however, rather peculiar; distal joint com.- paratively large and almost perfectly orbicular in outline, carrying 6 rather short setae, 2 of which are attached somewhat inside the edge; inner expansion of proximal joint quite short, with 5 marginal setae, the outermost one very small. Idyaeids Copepoda Suppl. Volume PI. XXXIII 6. O. Sars, del. 1. Idyella major, 6. O. Sars 2. „ exigua, 6. O. Sars 3. Idyanthe dilatata, 6. O. Sars Diosaccidas Copepoda Suppl. Volume PI. XXXIV 6. O. Sars, del. Stenheliopsis affinis, 6. O. Sars CanthocamptidaB Copepoda Suppl. Volume PI. XXXV 6. O. Sars, del. Attheyella Schmeili (Mrazek) Canthocamptidae Copepoda Suppl. Volume PI. XXXVI G. O. Sars, del. Ameira dubia, 6. 0. Sars Canthocamptidae Copepoda Suppl. Volume PI. XXXVII LLUy G. O. Sars, del. Ameira exilis, Scott Canthocamptidae Copepoda Suppl. Volume PI. XXXVIII 6. O. Sars, del. 1. Parameira longlremis (Scott) 2. „ intermedia (Scott) Canthocamptidae Copepoda Suppl. Volume PI. XXXIX G. O Sars, del. Pseudameira gracilis, 6. O. Sars Canthocamptidae Copepoda Suppl. Volume PI. XL 6. O. Sars, del. Pseudameira mixta, 6. O. Sars Canthocamptidae Copepoda Suppl. Volume PI. XLl G. O. Sars, del. Sienocopia minor, 6. 0. Sars Canthocamptidae Copepoda Suppl. Volume PI. XLII » 6. O. Sars, del. Cleiomesochra major, 6. O. Sars 1 Canthocamptidas Copepoda Suppl. Volume PI. XLIll G. O. Sars, del. Cletomesochra nana, 6. 0. Sars Canthocamptidae Copepoda Suppl. Volume PI. XLIV G. O. Sars, del. Cletomesochra rostrata, 6. 0. Sars Canthocamptidas Copepoda Suppl. Volume PI. XLV 6. O. Sars, del. Hemimesochra clavularis, G. O. Sars Laophontidae Copepoda Suppl. Volume PI. XLVI 6. O. Sars, del. Laophonte brevifurca, 6. O. Sars Laophontidae Copepoda Suppl. Volume PI. XLVII G. O. Sars, del. Laophonte tenera, G. 0. Sars LaophontidaB Copepoda Suppl. Volume PI. XLVIII 6. O. Sars, del. Laophonte abbreviata, 6. O. Sars 73 Colour not yet ascertained. Length of the specimen examined 0.55 mm. Remarks. This form may at once be distinguished from any of the other known species by its quite unusually short and stout body. In the structural details it seems to come nearest to L. litioraUs Scott, ^described in Vol. V, p. 255. On a closer comparison, however, some well marked diffe- rences are found to exist, especially as regards the outer ramus of the posterior antennae and the 1st and last pairs of legs. Occurrence. — A solitary, apparently fully grown female specimen of this form was found in a sample taken al Korshavn from a depth of about 30 fathoms. Gen. Harrietella, Scott, 1906. Generic Characters. — Body short and stout, with the anterior division pronouncedly depressed, the posterior much narrower. Rostral projection well defined and ciliated at the tip. Caudal rami comparatively short. Antennae and oral parts built on the same type as in Laophonte. The 3 anterior pairs of legs likewise of a very similar structure. 4th pair of legs, however, peculiarly developed, and much smaller than the 2 preceding pairs, with the number of joints in both rami reduced. Last pair of legs extended laterally; distal joint large, lamellar, proximal joint short and only very slightly expanded inside. 2 ovisacs present in female. Male unknown. Remarks.— Ihxs, genus was established in the year 1906 by Scott, to include a form previously described by him as a species of the genus Laophonte. Indeed, the affinity of this form to that genus is a very close one. Yet there are at least 2 characters which highly distinguish the present genus, and which alone seem to suffice for warranting its validity, viz., the peculiar structure of the 4th pair of legs and the presence in the female, as stated by Scott, of 2 ovisacs. Only a single species of this genus is as yet known. 60. Harrietella simulans, Scott. (PI. XLIX). Laophonte simulans, Scott, Twelfth Annual Report of the Fishery Board for Scotland, Part III, p. 248, PI. VII, figs. 24—32; PI. VIII, fig. 1. Specific Characters.— Female. Body remarkably short and broad, with the anterior division flattened. Cephalic segment very large and expanded' 11 — Crustacea. 74 occupying more than half the length of the anterior division, lateral edges finely ciliated; rostral projection rather prominent, with the tip narrowly rounded off and fringed with delicate cilia between the 2 usual sensory hairs. The 2 succeeding segments with the lateral parts lamellarly expanded and finely ciliated at the edges; the 3rd trunkal segment somewhat less broad, with the epimeral plates less fully developed; last segment very short. Urosome scarcely more than half as long as the anterior division and much narrower, tapered behind; genital segment nearly twice as broad as it is long and distinctly subdivided in the middle; the succeeding segments without any distinctly defined lateral expansions, but, like the genital segment, ciliated at the edges; last segment scarcely smaller than the preceding one and having the anal opercle well developed and minutely denticulate at the edge. Caudal rami about the length of the anal segment and somewhat divergent; apical setae moderately elongate. Anterior antennae rather slender, though n:t at- taining the length of the cephalic segment, and composed of 6 joints clothed with scattered rather long setae; 2nd joint somewhat dilated, but scarcely as long as the 3rd. Posterior antennae comparatively strongly built, with the spines attached to the terminal joint very coarse and somewhat curved at the tip; outer ramus small, uniarticulate, with 4 ciliated setae. Posterior maxillipeds very powerfully developed. 1st pair of legs also rather strongly built, with the inner ramus large and armed at the end with an unusually strong curved claw; outer ramus very narrow, 3-articulate, and extending a little beyond the middle of the proximal joint of the inner. The 2 succeeding pairs of legs of rather normale appearance. 4th pair of legs very unlike the preceding pairs and much smaller, 2nd basal joint produced outside to a long digitiform process ciliated on both edges and carrying on the tip the usual slender bristle; outer ramus only composed of 2 joints, the proximal of which is the shorter and provided outside with a thickish densely ciliated seta, distal joint of a somewhat irregular form and edged with 5 setae similar to that attached to the proximal joint, each seta springing off from a knob-like prominence of the edge; inner ramus composed of a single small joint carrying on the tip 2 setae. Last pair of legs with the proximal joint quite short and produced outside to a slender process tipped with a bristle, its inner part only very slightly expanded and provided with 3 marginal setae of about equal length; distal joint remarkably constricted at the base, but widening in its outer part to a broad hairy plate carrying 5 comparatively short marginal setae. Colour not yet ascertained. Length of adult female 0.51 mm. 75 Remarks.— The outward appearance of the present form is so peculiar that it cannot be confounded with any other member of the family Laophontldce, though there are a few species which exhibit a somewhat similar short and flattened shape of the body, for instance the form described in Vol, V, p. 273 as Laophoniodes expansus. This form is however otherwise very different. Occurence.— k single female specimen, only of this peculiar form has hitherto come under my notice. It was found in the bottom residue of a large collecting bottle containing several marine animals taken by Mr. Kjaer in the neighbourhood of Drebak from a depth of about 50 fathoms. The specimen was fully grown, but wanted the ovisacs. Distribution. — Scottish coast. Fam. Cletodidae. Gen. Cletodes, Brady. 61. Cletodes Sarsi, Scott. (PI. L). Cletodes Sarsii, Scott ; Twenty-third Annual Report of the Fishery Board for Scotland, Part III, p. 146, PI. XII, figs. 1—9. Specific Characters.— Female. Body very slender and gradually tapered behind, with all the segments sharply marked off from each other. Cephalic segment comparatively large, equalling in length the 3 succeeding segments combined ; rostral projection rather prominent and narrowly blunted at the tip. Urosome (including the caudal rami) nearly as long as the anterior division; genital segment not fully attaining the length of the 2 succeeding segments combined, and imperfectly subdivided in the middle; last segment comparatively small, with the anal opercle well marked and perfectly smooth. Caudal rami very slender and narrow, equalling about half the length of the remaining part of the tail, and slightly divergent; outer edge exhibiting at the end of the first Va of its length a well-marked notch, to which are attached 2 somewhat unequal bristles, another small bristle occurring near the end; dorsal seta issuing about in the middle; apical seta rather slender and flanked by 2 small bristles, the outer of which is partly connected with it at the base. Anterior antennae comparatively short and stout, scarcely exceeding half the length of 76 the cephalic segment, and composed of 5 joints, the 2nd of which is the largest and much longer than the 3rd; terminal joint oblong oval in form, with some of the setae distinctly ciliated. Posterior antennae and oral parts of the structure characteristic of the genus. Natatory legs rather poorly developed and not very dissimilar in structure; inner ramus in all of them considerably shorter than the outer and biarticulate; outer ramus without any setae inside. Last pair of legs with the distal joint long and narrow, sublinear in form, and provided with 4 marginal setae, 2 on the outer edge, one at the tip, and one on the inner edge, the latter very strong, spiniform; inner expansion of proximal joint forming a well defined narrow plate edged with 3 strong setae and extending about to the end of the first Va of the distal joint. Male resembling the female in the general form of the body, but easely recognisable by the strongly hinged anterior antennae. Inner ramus of 3rd pair of legs conspicuously transformed, being distinctly 3-articulate with the middle joint armed at the end outside with a strong spine; terminal joint small, with 2 slender setae on the tip. Colour not yet ascertained. Length of adult female 0.62 mm. Remarks. — The present species is easily recognised by the very slender and attenuated shape of the body, and more particularly by the structure of the last pair of legs and that of the caudal rami. Occurrence. — Some few specimens of this form were picked up from samples taken at Risor and Korshavn in depths ranging from 30 to 60 fathoms Distribiition.—Scoiiish coast (Scott). 62. Cletodes pusillus, G. O. Sars, n. sp. (Fl. LI). Specific Characters. —Female. Body of a similar slender and narrow shape to that in the preceding species, though somewhat less rapidly attenuated behind. Cephalic segment scarcely attaining the length of the 3 succeeding segments combined, and having the rostral projection less produced and blunted at the end. Urosome almost the length of the anterior division and nearly cylindrical in shape, with the last segment scarcely smaller than the preceding one. Caudal rami long and narrow, nearly attaining half the length of the remaining part of the tail; outer edge with a slight notch in front of the middle carrying a small bristle; dorsal seta issuing a little beyond this notch; apical seta about the length of the ramus. Anterior antennae comparatively 77 more slender than in the preceding species, though scarcely as long as the cephalic segment; 2nd joint of about same length as the 3rd, but somewhat broader. Posterior antennae with the outer ramus very narrow and only provided with a single seta issuing from the tip. Natatory legs comparatively more slender than in C Sarsi, with the setae of the inner ramus reduced in number. Last pair of legs with the distal joint less slender, oblong fusiform in outline, and carrying 5 marginal setae, 2 on the outer edge, 2 on the tip, and one inside near the end, none of the setae spiniform ; inner expansion of proximal joint very small, nodiform, with only 2 unequal setae; digitiform process issuing from same joint outside exceedingly long and slender. Male exhibiting the usual sexual differences from the female, the anterior antennae being conspicuously hinged, and the inner ramus of 3rd pair of legs transformed in a similar manner to that in the preceding species. Colour not yet ascertained. Length of adult female 0.51 mm. Remarks. — In the slender and narrow shape of the body this form resembles somewhat C. Sarsi. It is however rather inferior in size and, on a closer comparison, exhibits also several well-marked differences in the struc- tural details, as indicated in the above diagnosis. Occurrence.— 01 this form also only a small number of specimens have as yet come under my notice. They were found in samples taken at Risor from a depth of about 60 fathoms. 63. Cletodes leptostylis, G. O. Sars. (PI. LII). ? Syn : Cletodes longicaudata, Brady (not Boeck). Specific Characters.— Female. Body slender and attenuated, with the segments sharply marked off from each other. Cephalic segment about the length of the 3 succeeding segments combined; rostral projection of moderate size and terminating in 2 minute juxtaposed denticles. Urosome considerably exceeding in length the anterior division, and rapidly tapered behind; genital segment comparatively large and distinctly subdivided in the middle; last seg- ment much smaller than the preceding one. Caudal "rami exceedingly narrow and elongated, occupying more than Vs of the entire length of the body; outer edge with a well-marked notch near te base carrying 2 well-developed bristles and with another smaller bristle close to the end; dorsal seta attached considerably in front of the middle; apical seta shorter than the ramus, and, 78 as usual, flanked by 2 small bristles, the outer of which is connected with it at the base. Anterior antennae of moderate size, not fully attaining the length of the cephalic segment, with the first 2 joint comparatively short and combined scarcely longer than the 3rd. Posterior antennae with the outer ramus very small, bisetose. Natatory legs moderately slender, with the inner ramus in 1st pair nearly as long as the outer, in the succeeding pairs much shorter; outer ramus in the 2 anterior pairs without any setae inside, in the 2 posterior pairs with a well developed seta on the middle joint and 2 such setae inside the terminal joint, the latter joint unusually prolonged, exceeding in length the other 2 combined. Last pair of legs largely developed and highly chitinised; distal joint much elongated and provided with 5 exceedingly strong and densely plumose setae, 3 on the outer edge, one at the tip, and one on the inner edge near the end, each seta being attached to a well defined knob-like prominence; proximal joint with the outer digitiform process long and narrow, inner expansion of the joint produced in the form of a narrow, somewhat curved ramus densely ciliated inside, and extending along the distal joint until its posterior Vs part, outer part of the ramus armed with 4 slender spines. Colour not yet ascertained. Length of the specimen examined 0.55 mm. Remarks. — The above described form agrees in almost all its details so closely with the species recorded by Brady under the name of Cletodes longlcaudata, that I have been in much doubt, if it not more properly should be referred to that species, in spite of its much inferior size^). In any case the specific name longlcaudata cannot be retained for the present form, as this name had been previously assigned by Boeck to another species of the present genus (see Vol. V, p. 286). Occurrence.— k solitary, apparently fully grown female specimen of this form was found in a sample taken at Ris0r from a depth of about 30 fathoms. Distribution.— Ihniish Isles (Brady & Scott). 64. Cletodes perplexus, Scott. (PI. LIII). Cletodes perplexus, ScoU, Seventeenth Annual Report of the Fishery Board for Scotland, Part III, p. 257, PI. XI, figs. 12—20; PI. XII, fig. 1. Specific Characters.— Female. Body comparatively more robust than in any of the preceding species, and tapering somewhat behind. Cephalic 0 Brady gives the length to 0.79 mm., and Scott tp no less than 0.84 mm. 79 segment about the length of the 3 succeeding segments combined and broadly rounded in front; rostral projection rather prominent, and terminating in an acute somewhat recurved point. Last trunkal segment comparatively large and tumid. Urosome not fully attaining the length of the anterior division; genital segment fully as long as the 2 succeeding segments combined, and distinctly subdivided in the middle; last segment exceeding in length the preceding one and conspicuously contracted distally. Caudal rami rather slender and narrow, about half the length of the remaining part of the tail; outer edge with 2 successive small bristles in its anterior half; dorsal seta issuing at the end of the first Va of the ramus; apical seta rather slender. Anterior antennae com- paratively short and stout, scarcely exceeding half the length of the cephalic segment; 2nd joint much the largest, being nearly twice as long as the 3rd. Posterior antennae rather strongly built, with the terminal joint considerably dilated at the end, innermost apical seta remarkably strong and cloted on the outer edge with long cilia; outer ramus more fully developed than in the other species and provided with 3 marginal setae. Oral parts normal. Natatory legs likewise built in the usual manner, though comparatively rather small; outer ramus in all of them without any setae inside. Last pair of legs very peculiar and unlike those in any of the other known species; proximal joint without any bristle-bearing process outside, its inner part considerably expanded and highly chitinised carrying inside 2 successive spiniform setae and produced at the end to a long mucroniform process denticulated in its outer part and pointing obliquely backwards and outwards; distal joint very small and im- perfectly defined at the base, with 3 comparatively short setae. Male of about same size as female and very like it in its general appearance, though easily recognisable by the distinctly hinged anterior antennae. Last pair of legs scarcely different from those in female. Colour pale whitish grey. Length of adult female 0.55 mm. Remarks.— The highly remarkable structure of the last pair of legs is sufficient for at once distinguishing the present form from any of the other known species. In the other structural details it shows itself however to be a true member of the present genus. Occurrence.-- Two specimens only of this form, a female and a male, have as yet come under my notice. They were found last summer (1918) at Hvaler, outside the Christiania Fjord, in a depth of about 6 fathoms, muddy bottom. Distribuction. — Scottish coast (Scott). so Gen. Mesocletodes, G. O. Sars. Remarks.— 'This genus was established by the present author to include the form described by Scott as Cletodes irrasa, which I found differed in certain points so materially from the other members of the present family as more properly to be separated from them generically. The validity of this genus I am now -enabled to confirm by adding 3 other species which are evidently congeneric with the above-mentioned form. 65. Mesocletodes monensis, (Thompson). (PI. LIV). Cletodes monensis, I. C. Thompson, Proc. & Transact, of Liverpool Zool. Society, Vol. VII, p. 200, PI. XXXIV. Specific Characters. — Female. Body comparatively more slender than in the type species and about of equal width throughout; all the segments minutely denticulate at the hind edge. Cephalic segment about the length of the 3 succeeding segments combined and somewhat contracted in its anterior part; rostral projection well defined and slightly curved downwards, with the tip acutely pointed; dorsal face of the segment somewhat vaulted and ex- hibiting behind the middle a very conspicuous horn-like process curved back- wards. Urosome about the length of the anterior division; genital segment of moderate size and imperfectly subdivided in the middle; last segment nearly as large as the 2 preceding segments combined, and having the anal opercle some- what prominent and armed dorsally with 2 successive denticles, the posterior one rather coarse and pointing backwards. Caudal rami slender and narrow, though not nearly attaining half the length of the remaining part of the tail; outer edge with 2 small bristles, the one attached at a short distance from the base, the other close to the end; dorsal seta issuing somewhat in front of the middle; apical setae very unequal, the middle one much the largest and about as long as the ramus, the innermost extremely small. Anterior antennae rather slender, nearly attaining the length of the cephalic segment, and composed of 7 sharply defined joints clothed with comparatively short, partly spiniform setae; 2nd joint much the largest; antepenultimate joint about the length of the last 2 joints combined. Posterior antennae with the outer ramus very small, bisetose. Oral parts agreeing in structure with those in the type species. Natatory legs like- wise rather similar, though comparatively somewhat less slender; inner ramus very small, but, as in the type species, distinctly biarticulate. Last pair of legs confluent in the middle; distal joints narrow linear in form, not dilated 81 at the end, and provided with 6 marginal setae, 3 very small on the outer edge, and 3 on the tip; inner expansion of proximal joint more distinctly defined than in the type species, and carrying 3 well-developed marginal setae. Ovisac very small. Colour whitish grey. Length of adult female 0.87 mm. Remarks. — The present form, first described by I. C. Thompson, may at once be distinguished from the type species, M. Irrasus Scott, by the peculiar horn-like process springing off from the dorsal face of the cephalic segment. In the more general structural details it shows a near relationship to that species, though, on a closer comparison, some well-marked minor differences may be found to exist, especially as regards the mutual relations of the joints in the anterior antennae and the shape of the last pair of legs. Occurrence. — I have only met with this form in a single locality on the Norwegian coast, viz., at Ris0r, where it occurred occasionally in a depth of about 50 fathoms, coarse muddy sand. All the specimens obtained were of the female sex. Distribution. — Liverpool Bay (Thompson). 66. Mesocletodes abyssicola, (Scott). (PI. LV). Cletodes abyssicola, Scott, On some Entomostraca collected in the Arctic Seas by W. Bruce. Ann. Mag. Nat. Hist, sen 7, Vol. VIII, p. 347, PI. V, figs. 1—8. Specific Characters. — Female. Body comparatively a little less slender than in the preceding species, with the segments coarsely denticulate at the hind edge. Cephalic segment somewhat tumid, with the frontal part broadly rounded off; rostral projection very small, almost obsolete; dorsal face of the segment considerably vaulted and armed behind, as in the preceding species, with a strong spiniform process still more prominent and curved than in that species. Urosome, as in the other species of the present genus, nearly of uniform width throughout, with the last segment rather large; anal opercle tipped with a strong upturned tooth. Caudal rami very narrow and quite excessively produced, occupying more than Vs of the entire length of the body, each ramus provided in the middle with 2 small bristles, the one lateral, the other dorsal; apical setae very short. Anterior antennae comparatively slender, exceeding somewhat in length the cephalic segment, and, as in the preceding species, composed of 7 joints, the 2nd of which is rather broad, though 12 — Crustacea. 82 scarcely as long as the 3rd; the 4 outer joints very narrow and subequal in size, constituting together the terminal part of the antenna, as shown by the position of the aesthectask which is attached to the 3rd instead, as usual, to the 4th joint. Posterior antennae with the outer ramus very minute and only tipped with a single seta. Oral parts scarcely different from those in the other species. Natatory legs with the inner ramus very small, uniarticulate; outer ramus in the 3 posterior pairs exceedingly slender and narrow. Last pair of legs with the proximal joint scarcely at all expanded inside, and only provided with a single small seta on the posterior edge; distal joint narrow linear in form, with a small bristle outside beyond the middle, and with 3 unequal apical setae. Colour pale whitish grey. Length of adult female 0.84 mm. Remarks. — The near relationship of the present form to the preceding one is clearly shown by the presence of a quite similar spiniform process on the dorsal face of the cephalic segment. It is however at once distinguished from that species by the excessively prolonged and narrow caudal rami, as also by the very small rostral projection. Some aberrant characters, as to the struc- ture of the anterior antennae and legs, have moreover been indicated in the above diagnosis. Occurrence. — 2 or 3 female specimens only of this form have as yet come under my notice. They were found at Ris0r at the considerable depth of about 100 fathoms, muddy bottom. Distribution. — Arctic Sea (Scott). 67. Mesocletodes inermis, G. O. Sars, n. sp. (PI. LVI). Specific Characters.— Female. Body resembling somewhat in shape that of M. monensis, though on the whole rather more robust. Cephalic seg- ment, as in that species, slightly contracted in front, with the rostral projection well defined and r-ather prominent, tridentate; dorsal face of the segment not much vaulted and without any trace of a spiniform process. Urosome about the length of the anterior division, with the last segment rather large; anal opercle not much prominent and edged with about 5 small denticles. Caudal rami only slightly longer than the anal segment, but of the usual narrow linear shape, with 2 small bristles, rather remote from each other, on the outer edge; dorsal seta issuing somewhat beyond the middle; apical setae comparatively 83 short. Anterior antennae rather slender, nearly attaining the length of the cephalic segment, and composed of 8 well defined joints, the 2nd of which is, as usual, the largest, though scarcely as long as the 2 succeeding joints combined, the 4 outer joints, composing the terminal part of the antenna, of about equal size. Posterior antennae comparatively small, with the outer ramus poorly developed, bisetose. Oral parts of the stucture characteristic of the genus. Natatory legs comparatively less slender than in the other species, and coarsely aculeate outside, inner ramus reduced to a minute nodiform prominence carrying in the 1st pair only one, in the other pairs 2 small bristles. Last pair of legs with the distal joint of the usual narrow linear form, and provided with 5 marginal setae, 3 apical and 2 lateral, the latter attached to the outer edge beyond the middle; inner expansion of proximal joint produced to a well defined narrow linguiform lamella carrying on the end 2 rather slender and distinctly ciliated setae accompanied outside by a very small spinule. Colour brownish grey. Length of adult female 0.86 mm. Remarks. — This new species is nearly allied to M. monensis, the general form of the body being rather similar, though somewhat more robust. It is however at once distinguished from that species by the absolute absence of any dorsal process on the cephalic segment. The specific name here pro- posed alludes to this want. As to the structural details, it moreover differs in the distinctly 8-articulate anterior antennae and in the rudimentary condition of the inner ramus of the natatory legs. Occurrence.—Several specimens of this form, all of the female sex, were found at Riser in depths ranging from 30 to 60 fathoms, coarse muddy sand. Gen. Eurycletodes, G. O. Sars. Remarks. — Of this genus 4 species have been described in Vol. V of the present work. To these are now added 4 others, increasing the number of Norwegian species of this genus to 8 in all. 68. Eurycletodes serratus, G. O. Sars, n. sp. (PI. LVII). Specific Characters.— Female. Body comparatively short and stout, of nearly equal width throughout, with all the segments coarsely denticulate at th^ hind edge. Cephalic segment scarcely as long as the 2 succeeding seg- 84 ments combined, and produced in front to a rather prominent acutely pointed rostral projection. Urosome about the length of the anterior division, with the 3 anterior segments produced on each side to well-marked spiniform pro- minences, giving that part a pronouncedly serrate appearance; last segment very large and, viewed from above, regularly quadrangular in outline; anal opercle edged with scattered strong denticles (about 5 in number). Caudal rami resembling in shape those in E. laticaudaias, being rather narrow and somewhat tapered distally; dorsal seta issuing from a knoblike prominence at a short distance from the end of the ramus. Anterior antennae not fully attaining the length of the cephalic segment and, as in the other known species, composed of 6 joints, 3 of which belong to the terminal part, 1st joint the largest, 2nd joint a little shorter than the 3rd; terminal part about the length of the 2 preceding joints combined, with the last joint rather produced. Posterior antennae without any trace of an outer ramus. Mandi- bular palp distinctly biarticulate. Posterior maxillipeds moderately strong. Natatory legs with both rami well developed; the inner one biarticulate and in 1st pair nearly as long as the outer, in the succeeding pairs rather shorter. Last pair of legs with the distal joint oblong oval in form and only slightly tapered distally, marginal setae 5 in number; inner expansion of prox- imal joint not much produced and carrying 3 subequal setae. Colour dark grey. Length of adult female 0.87 mm. Remarks. — The present form is nearly allied to the type species, E. laticaudatus (Boeck), agreeing with it rather closely in most of the structural details. It is however of considerably larger size, and moreover at once distinguished by the conspicuously serrated edges of the urosome, in which latter respect it more resembles E. latus (Scott). Occurrence.— ^Some few female specimens of this fine species were taken at Riser from a depth of 60 — 80 fathoms, muddy bottom. 69. Eurycletodes oblongus, G. O. Sars, n. sp. (PI. LVIII). Specific Characters. — Female. Body comparatively more slender than in the preceding species, oblong in form, with the segments less coarsely denticulated at the hind edges. Cephalic segment fully as long as the 3 suc- ceeding segments combined, and produced in front to a broadly triangular rostral projection. Urosome scarcely attaining the length of the anterior 85 division and somewliat less broad, with the anterior segments produced laterally to well defined, posteriorly-pointing acute projections; last segment very large, with the lateral edges somewhat arched and minutely denticulate; anal opercle edged with about 10 strong denticles. Caudal rami comparatively small, being only slightly longer than they are broad; dorsal seta issuing from a rather prominent tubercle somewhat in front of the middle; apical setae unusually short. Anterior antennae not nearly attaining the length of the cephalic seg- ment; 2nd joint shorter, but much broader than the 3rd; terminal part about the length of those joints combined. Posterior antennae rather small, with the outer ramus replaced by a simple seta. Posterior maxillipeds comparatively strong. Natatory legs with the inner ramus poorly developed, only consisting of a single joint, carrying in the 2 anterior pairs 4, in the 2 posterior pairs only 2 setae. Last pair of legs with the distal joint narrow oblon^^ in form and only provided with 4 setae, 2 apical and 2 lateral; inner expansion of proximal joint conically produced, and extending about to the middle of the distal joint, tip provided with 2 subequal setae. Colour whitish grey. Length of adult female 0.78 mm. Remarks. —In the structural details this form seems to approch nearest to E. major G. O. Sars. It is however rather inferior in size and moreover at once distinguished by the well-marked lateral armature of the anterior seg- ments of the urosome, as also by the less produced caudal rami. Occurrence. — Two female specimens only of this form have as yet come under my notice. They were taken at Ris0r from a depth of about 30 fathoms. 70.. Eurycletodes acuieatus, G. O. Sars, n. sp. (PI. LIX). Specific Characters. — Female. General form of the body somewhat resembling that in E. oblongus, though perhaps a little shorter and stouter. Cephalic segment scarcely longer than the 2 succeeding segments combined; rostral projection only slightly prominent and obtusely pointed at the end. Urosome about the length of the anterior division, and having the hind edges of the segments very coarsely dentate, the outermost tooth on the 2 anterior segments being much stronger than the others and projecting on each side. Last caudal segment large, with the lateral edges slightly convex and finely hairy; anal opercle broadly rounded off and edged with about 12 denticles of 86 moderate size. Caudal rami comparatively small, though somewhat longer than they are broad; dorsal seta issuing about in the middle from a well- marked knob-like prominence; apical setse of moderate length. Anterior antennae nearly attaining the length of the cephalic segment; 2nd joint rather short, scarcely more than half as long as the 3rd; 4th joint unusually pro- duced anteriorly. Posterior antennae, as in the preceding species, with the outer ramus replaced by a simple seta. Posterior maxillipeds moderately strong. Natatory legs with the inner ramus uniarticulate, largest on the 1st pair and successively diminishing in size on the succeeding pairs. Last pair of legs with the distal joint very narrow and somewhat tapered towards the end, car- rying 4 setae, the proximal one rather remote from the other 3, which issue from the outermost part of the joint; inner expansion of proximal joint only slightly produced and provided with 2 subequal setae. Colour whitish grey. Length of adult female 0.73 mm. Remarks. — The present form may be easily recognised by the unusu- ally coarse dentation of the caudal segments, a character which has given rise to the specific name here proposed. In the structure of the several appendages it seems to come nearest to E. oblongiis. Occurrence.— -Som^ female specimens of this form were obtained at Risor in a depth of about 50 fathoms, muddy bottom. It also occurs occasio- nally at Korshavn in about- the same depth. 7L Eurycletodes minutus, G. O. Sars, n. sp. (PI. LX). Specific Characters. — Female. Body short and stout, with the anterior division conspicuously broader than the posterior and somewhat depressed. Cephalic segment comparatively large, considerably exceeding in length the 2 succeeding segments combined, and gradually somewhat contracted in front; rostral projection only slightly prominent and obtusely pointed at the end. Urosome much shorter than the anterior division and narrower than usual, with the segments uniformly denticulated at the hind edges and the lateral corners not produced; last segment, as usual, of rather large size, with the lateral edges slightly convex and finely hairy; anal opercle quite smooth at the edge. Caudal rami about twice as long as they are broad and only slightly tapered distally; dorsal seta issuing about in the middle; apical setae of moderate length. Antennae and oral parts resembling in structure those in 87 the 2 preceding species. Natatory legs with the inner ramus still more reduced in size and apparently quite wanting on the 4th pair; outer ramus in this and the 2 preceding pairs very slender and narrow. Last pair of legs with the distal joint narrow linear in form and imperfectly defined at the base, marginal setse rather small and 4 in number; inner expansion of proximal joint very slightly produced and carrying 2 unequal setae. Colour whitish grey. Length of adult female 0.53 mm. Remarks. — This small species may be easily recognised by the some- what unusual shape of the body, the anterior division being, unlike what is generally the case, conspicuously broader than the posterior. In the structural details it shows itself however to be a true member of the present genus. Occurrence. — Some few specimens of this form, all of the female sex, were found at Riser in depths ranging from 30 to 50 fathoms, muddy bottom. Gen. Leptocletodes, G. O. Sars, n. Generic Characters. — Body of slender form, with very thin and fragile integuments. Rostral projection inconspicuous. Urosome narrower than the anterior division, with the segments scarcely denticulate behind; last segment comparatively large. Caudal rami narrow and rather far apart. Anterior antennae 7-articulate, with the terminal joint elongate. Posterior antennae small with the outer ramus imperfectly developed. Mandibular palp distinctly biarticu- late. Maxillae with a small exopodal lobe tipped with a single bristle. Max- illipeds normal. Natatory legs slender, with both rami well developed, the inner one shorter than the outer and biarticulate. Last pair of legs with the proximal joint scarcely expanded inside; distal joint long and slender. Male unknown. Remarks. — This new genus is only founded on a single species, which however cannot properly be referred to any of the hitherto known genera of the present family, though in some respects apparently approaching somewhat the genus Eurycletodes. The generic name here proposed alludes both to the comparatively slender form of the body and to the very thin and fragile integuments. 88 72. Leptocleiodes debilis, G. O. Sars, n. sp. (PI. LXI). Specific Characters.— Female. Body rather slender and narrow, with the anterior division only slightly dilated, though somewhat broader than the posterior. Cephalic segment exceeding in length the 2 succeeding segments combined, and somewhat vaulted dorsally; frontal margin slightly produced in the middle, though not forming any true rostrum. Last trunkal segment com- paratively small. Urosome not attaining the length of the anterior division, and rather narrow, cylindrical in form; genital segment fully as long as the 2 succeeding segments combined and imperfectly subdivided in the middle; last segment oblong quadrangular in outline, with the anal opercle broadly truncated at the end and perfectly smooth. Caudal rami widely apart, and narrow linear in form, not however attaining the length of the anal segment, both the outer and inner edge carrying beyond the middle a small seta; dorsal seta issuing near the end of the ramus; apical setae rather slender. Anterior antenna fully as long as the cephalic segment and composed of 7 well defined joints clothed with scattered comparatively short setae; the first 2 joints about equal in size, each of them equalling in length the 2 succeeding joints combined; terminal part of the antenna, composed of the 3 outer joints, almost as long as the proximal one, with the last joint rather large, fully as long as the other 2 combined. Posterior antennae rather feeble, with the outer ramus very small, uniarticulate, and tipped by a single seta. 1st pair of natatory legs, as usual smaller than the others, with the rami less unequal in length, the outer one being only slightly longer than^the inner and without any setae inside. The 3 succeeding pairs o| legs with the outer ramus very slender and narrow, inner one successively somewhat diminishing in length, extending in 2nd pair beyond the middle joint of the outer, in 4th pair only as far as the 1st joint of that ramus. Last pair of legs with the proximal joint produced outside to a long digitiform process tipped with a slender bristle, inner part of the joint not at all expanded, and only provided behind with a single seta arising from a knoblike prominence of the margin; distal joint greatly produced and narrow linear in form, though a little dilated in its outer part, and carrying 4 com- paratively small marginal setae, 2 lateral and 2 apical. Colour whitish pellucid. Length of adult female 0.63 mm. Remarks. — In its outward appearance this form somewhat reminds on Fultonia hirsuta Scott (see Vol. V, p. 341), which however otherwise is rather 89 different, and has been referred provisionally by the present author to another family, viz., the Tachidiidce. The great fragility of the animal renders its exact examination rather difficult, and has indeed given rise to the specific name here proposed. Occurrence. — Some specimens of this form, all of the female sex, were found at Ris0r in depths ranging from 50 to 100 fathoms, muddy bottom. Gen. Pseudodetodes, G. O. Sars, n. Generic Characters. — Body slender and attenuated, with strongly chitinised integuments, and all the segments distinctly denticulate at the hind edge. Cephalic segment peculiarly expanded below, and produced in front to a well defined rostral projection. Urosome with the segments somewhat expanded laterally; last segment .smaller than the preceding ones. Caudal rami somewhat produced and rather narrow. Anterior antennae of moderate size, but with the number of joints much reduced. Posterior antennae with the outer ramus well defined, uniarticulate. Mandibular palp likewise uniarticulate. Maxillae without any distinctly defined exopodal lobe. Anterior maxillipeds with 3 setiferous lobes inside the basal part. Posterior maxillipeds moderately strong. 1st pair of legs small, with both rami biarticulate; the 3 succeeding pairs with the outer ramus distinctly triarticulate and very slender, inner ramus biarticulate and shorter than the outer. Last pair of legs of rather a peculiar shape, the proximal joint being remarkably produced both outside and inside, distal joint comparatively small. Male unknown. Remarks. — This genus also is only founded on a single species, which however exhibits several very conspicuous peculiarities both as to the outward appearance and the structural details, preventing its reference to any of the hitherto known genera of the present family. 73. Pseudodetodes typicus, G. O. Sars, n. sp. (PI. LXII). Specific Characters. — Female. Body of rather slender form and gradu- ally attenuated behind, with the segments rather sharply marked off from each other. Cephalic segment of very large size, occupying rather more than half the length of the anterior division, and forming below on each side a broad 13 — Crustacea. 90 lamellar expansion covering at the sides the oral area; rostral projection con- siderably prominent, with the end narrowly produced and terminating in 2 small juxtaposed points. Urosome somewhat shorter than the anterior division, with the lateral parts of the segments slightly prominent and rounded off; genital segment comparatively large and distinctly subdivided in the middle; last segment shorter than the preceding one, with the anal opercle coarsely denticulate at the edge; all the caudal segments containing within their lateral parts a very conspicuous rounded opaque body of apparently glandular nature. Caudal rami slightly exceeding in length the anal segment and rather narrow, with 2 juxtaposed bristles on the outer edge at a short distance from the end; dorsal seta issuing a little farther behind; apical setae very slender. Anterior antennae nearly as long as the cephalic segment, and only composed of 4 distinctly defined joints clothed with scattered comparatively short and stout setae; 2nd joint produced behind in the middle to a strong claw-like projection; 3rd joint about the length of the first 2 joints combined, and exhibiting at the end, in addition to the projection carrying the usual aesthetask, a small conical process tipped with a seta, and apparently representing the remnant of a small joint originally intercalated between it and the succeeding (last) joint, but otherwise wholly coalesced with the former; terminal joint about as long as the 3rd, but much narrower. Posterior antennae of moderate size; outer ramus formed by a small, but well defined joint carrying on the tip 2 somewhat unequal setae. 1st pair of legs much smaller than the succeeding ones and, as usual, armed at the inner corner of the 2nd basal joint with a deflexed spine; inner ramus somewhat shorter and much narrower than the outer, with the distal joint comparatively small, and carrying on the tip a slender seta accompanied by a short bristle; outer ramus without any setae inside, its distal joint of about same size as the proximal one, and armed at the end with 3 slender spines followed by a somewhat longer ciliated seta. The 3 succeeding pairs of legs with the outer ramus very slender and narrow and without any seta inside the 1st joint; inner ramus in 2nd pair extending about to the end of the middle joint of the outer, in the 3rd and 4th pairs successively shorter. Last pair of legs with the distal joint very small, oval in form, and edged with 4 setae; proximal joint produced outside to a long digitiform process tipped with a slender bristle; inner expansion exserted to a long conical lappet extending far beyond the distal joint, and tipped with a slender seta accompanied outside by a very minute bristle. Colour pale yellowish grey. Length of adult female 0.62 mm. 91 Remarks. — In the slender and attenuated shape of the body this form bears a general resemblance to some species of the genus Cletodes. It is however at once recognised from them by the peculiar shape of the cephalic segment, as also by the rather different structure of the anterior antennae and of the 1st and last pairs of legs. Occurrence. — Some few female specimens of this peculiar form were found at Riser in depths ranging from 30 to 60 fathoms, coarse muddy sand. Gen. Nannopus, Brady. Remarks. — Two species only of this genus are as yet known, the one (the type), N. palustris Brady, occurring in brackisk water on the coasts of northern Europe and described in Vol. V, p. 307, the other having been recorded by the present author form the great fresh-water lake Tanganyika in Central Africa, under the name of Ilyophllus perplexus. I am now enabled to add a 3rd very distinct species, which, unlike the other two, is a true marine and deep-water form. 74. Nannopus abyss!, G. O. Sars, n. sp. (PI. XLIII). Specific Characters. — Female. Body short and stout, gradually tapered behind, with the segments not very sharply marked off from each other and perfectly smooth. Eye absent. Cephalic segment about equalling in length the 3 succeeding segments combined, and evenly vaulted above; rostral pro- jection abruptly deflexed, with the tip obtusely pointed and only provided on each side with a single sensory hair. Urosome scarcely longer than the exposed part of the trunk; genital segment comparatively large and imper- fectly subdivided in the middle; last segment much shorter than the preceding one, with the anal opercle very small. Caudal rami about twice as long as they are broad at the base, and , somewhat tapering distally, each ramus armed, inside the 2 juxtaposed bristles of the outer edge, with a short transverse row of small spinules; dorsal seta issuing near the base of the ramus; apical setae comparatively short, the middle one of quite normal appearance. Anterior antennae short and stout, scarcely exceeding half the length of the cephalic segment and, as in the other 2 species, composed of 5 joints clothed with rather strong, for the most part ciliated setae; the first 3 joints successively diminishing in size, the 3rd being rather produced at the end anteriorly, the 92 outer 2 joints, composing the terminal part of the antenna, abruptly much smaller and subequal in size, the last one carrying behind an unusually thick and coarsely ciliated seta. Posterior antennae very strongly built, with the terminal joint coarsely aculeate outside; outer ramus comparatively large, lamellar, with 6 strong marginal setae. Mandibular palp likewise very fully developed and distinctly biramous, with the basal part considerably expanded and provided at the prominent inner corner with 4 strong curved set«; both rami uniarticulate and of unequal size, the inner one being much the larger. Maxillae with both the exopodal and epipodal lobes well defined. Maxillipeds resembling in structure those in the other 2 species. 1st pair of legs well developed and coarsely aculeate outside; inner ramus biarticulate and a little shorter than the outer. The 3 succeeding pairs of legs without the slightest trace of an inner ramus; outer ramus normally developed and only sligtly longer than that of the 1st pair. Last pair of legs extremely small, though distinctly biarticulate, both joints simple, not expanded. Ovisac globular, with only a small number of comparatively large ova. Colour whitish grey. Length of adult female 0.68 mm. Remarks. — This is a very distinct form, differing in some points rather markedly from the 2 previously known species, though evidently referable to the same genus. The most prominent differences relate to the great reduction of the last pair of legs and the absolute absence of an inner ramus on the 3 posterior pairs of natatory legs. On the other hand are the antennae and the oral parts rather more fully developed than in those species, though built on the very same type Occurrence. — A solitary specimen only of this interesting form, an ovigerous female, has as yet come under my notice. It was found at Riser in the considerable depth of nearabout 100 fathoms, muddy bottom. Fam. Tachidiidae. Gen. Danielssenia, Boeck. Remarks. — This genus, which is identical with Jonesiella of Brady, comprises as yet 4 species, 2 of which are described in Vol. V of the present work, the other 2 being recorded from the Arctic Seas. I am now enabled to add a 5th well defined and rather large species, to be described below. Laophontjdas Copepoda Suppl. Volume PI. XLIX 6. O. Sars, del. Harietella simulans, Scott CletodJdae Copepoda Suppl. Volume PI. L :^. iS- ' ',!£- 6. O. Sars, del. Cletodes Sarsi, Scott Cletodidae Copepoda Suppl. Volume PI. LI G. O. Sars, del. Cletodes pusillus, 6. O. Sars Cletodidas Copepoda Suppl. Volume PI. Lll 6. O. Sars, del. Cletodes leptostylis, 6. O. Sars I Cletodidae Copepoda Suppl. Volume PI. Llll G. O. Sars, del. Cletodes perplexus, Scoii Cletodidae Copepoda Suppl. Volume PI. LIV -r^'. St ' ns: '%. / %. V G. O. Sars, del. Mesocletodes monensis, (Thomps.) Cletodidae Copepoda Suppl. Volume PI. LV 6. O. Sars, del. Mesocletodes abyssicola, (Scott) Cletodidae Copepoda Suppl. Volume PI. LVI •^K^^^^yf^^^\ 6. O, Sars, del. Mesocletodes inermis, G. O. Sars Cletodidae Copepoda Suppl. Volume PI. LVII 6. O. Sars, del. Eurycletodes serratus, 6. O. Sars Cletodidae Copepoda Suppl. Volume PI. Lvm 6. O. Sars, del. Eurycletodes oblongus, 6. O. Sars Cletodidae Copepoda Suppl. Volume PI. LIX X-^a^ G. O. Sars, del. Eurycletodes aculeatus, 6. O. Sars CietodJds Copepoda SuppL Volume PI. LX Tif^'' 6. O. Sars, del. Eurycletodes minutus, 6. O. Sars r CletodidaB Copepoda Suppl. Volume PI. LXI 6. O. Sars, del Leptocletodes debilis, 6. O. Sars Cletodidae Copepoda Suppl. Volume PI. LXII n-i, a,^. 6. O. Sars, del. Pseudocletodes typicus, 6. O. Sars i Cletodidae Copepoda Suppl. Volume PI. LXIIi G. O. Sars, del. Nannopus abyssi, 6. O. Sars Tachidiidae Copepoda Suppl. Volume PI. LXIV 6. O. Sars, del. Danielssenia robusta, G. 0. Sars 93 75. Danielssenia robusta, G. O. Sars, n. sp. (PI. LXIV). Specific Characters.— Female. Body comparatively robust, with the anterior division rather dilated and evenly vaulted above. Cephalic segment nearly as long as the 3 succeeding segments combined, and produced in front to a thin rostral plate obtusely rounded and somewhat defexed at the end. Epimeral plates of the 3 succeeding segments somewhat produced behind. Last trunkal segment very small. Urosome comparatively short, scarcely attaining half the length of the anterior division, and only very slightly tapered behind, its segments minutely denticulate at the hind edges; genital segment about the length of the 2 succeeding segments combined; last segment some- what smaller than the preceding one. Caudal rami very short, being scarcely half as long as they are broad; apical set« rather slender. Anterior antennae, as in the type species, only composed of 4 joints, and exhibiting a very similar structure and armature. Posterior antennae likewise very similar. Man- dibular palp with the basal part considerably expanded, and carrying along the hind edge of the projecting inner part 4 strong ciliated setae. Maxillae and maxillepeds scarcely differing in their structure from these parts in the other species. Natatory legs likewise built on the same type, though differing in the inner ramus being somewhat more produced. Last pair of legs com- paratively of smaller size than in the other 2 Norwegian species, with the distal joint less broad and having the innermost seta spiniform; inner expansion of proximal joint far less produced, scarcely extending beyond the distal joint, and only provided with 3 marginal setae. Colour whitish grey, with a fainte rosy tinge. Length of adult female about 1 mm. Remarks.— The present form is nearly allied to the other 2 Norwegian species, through more robust in shape, and also of larger size than any of them. The structure of the several appendages agrees on the wole rather closely with that found in the said species, except the last pair of legs, which are of much smaller size and also conspicuously different in shape. Occurrence. — Several specimens of this large species, most of them of the female sex, were found at Riser in depths ranging form 30 to 60 fathoms, coarse muddy sand. 14 - Crustacea. 94 Gen. Psammis, G. O. Sars. Remarks. — This genus was established by the present author in the year 1911, to include a single species of which at that time only 2 female specimens had come under my notice. I have subsequently had an oppor- tunity of examining also a fully adult male specimen, and, as the sexual diffe- rences in this form are rather striking, both as regards the outward appearance and the structure of some of the appendages, I have found it advisable to give below a full description of the specimen accompanied by figures of the whole animal and of some of the structural details. 76. Psammis longisetosa, G. O. Sars. (PI. LXV). See Vol. V, p. 339, PI. CCXXV. Specific Characters. — Male. Body considerably more slender than in female and gradually tapered behind. Cephalic segment about occupying half the length of the anterior division, and provided in front with a well-defined and rather prominent rostral plate of regularly oval form, with 2 delicate sen- sory hairs on each side. Urosome about equalling in length ^U of the anterior division, and composed of 5 well defined segments, the 4 anterior of which are of about equal size; last segment considerably smaller and somewhat widening distally, with the anal opercle inconspicuous. Caudal rami consider- ably divergent, with the apical setae greatly prolonged. Anterior antennae very strongly built and conspicuously hinged, being apparently composed of 7 joints, the penultimate of which is strongly inflated, almost globose in form; terminal joint narrow unguiform and very mobile, admitting of being impinged against the anterior face of the preceding joint, both together forming a very powerful grasping organ. Posterior antennae and oral parts scarcely different from those in female. 1st pair of legs also rather similar, only differing in the shape of the spine issuing from the inner corner of the 2nd basal joint, this spine being not, as in the female, straight, but distinctly curved inwards. 2nd pair of legs with the inner ramus conspicuously transformed, each of the joints being produced at the end outside to a well defined acuminate process, that of the middle joint being much the largest, mucroniform, and extending almost to the end of the terminal joint. The 2 succeeding pairs of legs of the very same structure as in the female. Last pair of legs however very different, the distal joint being not, as in the female confluent with the proximal one, but 95 well defined, rounded in form and carrying 4 slender marginal spines; inner expansion of proximal joint comparatively small, scarcely extending beyond the middle of the distal joint, and only provided with 2 spines of somewhat unequal length. Length of the specimen examined 0.72 mm. Remarks. — The identification of the above-described form as the male of P. loiigisetosa cannot be contested, though some of the characters, especi- ally the structure of the last pair of legs, are not in accordance with the diagnosis previously given of the genus. Occurrence. — The above-described male specimen was, like the female, found at Farsund. I have not met with this form in any other locality on the Norwegian coast. Gen. Argestes, G. O. Sars. Remarks.— l\i\s is another genus originally founded only on a single species, A. mollis G. O. Sars, found at Bukken, south west coast of Norway. A slender Copepod recently found off the southern coast seems, according to the structural details, to be referable to the same genus, though in its outward appearance it looks rather different from the type species. A description of this form is given below. 77. Argestes tenuis, G. O. Sars, n. sp. (PI. LXVII). Specific Characters. — Female. Body slender and narrow, with the anterior division only slightly dilated, and the integuments very thin and pellucid. Cephalic segment somewhat exceeding in length the 2 succeeding segments combined, and without any distinctly defined rostral projection. Lateral parts of the 3 succeeding segments rounded off; last trunkal segment smaller than the preceding one. Urosome narrow cylindrical in form, and nearly attaining the length of the anterior division, its segments very finely den- ticulate at the hind edges, and clothed laterally with delicate adpressed spikes; genital segment comparatively large and conspicuously protuberant below in its anterior part; last segment somewhat larger than the preceding segment and quadrangular in outline, anal opercle very broad and perfectly smooth at the edge. Caudal rami about the length of the anal segment and narrow linear in form, with all the setae issuing from the slightly thickened extremity, the 2 middle apical setae very slender. Anterior antennae nearly as long as 96 the cephalic segment and, as in the type species, composed of 7 well defined joints clothed with rather strong finely denticulated setae; the first 2 joints much larger than the others, terminal part, composed of the 3 outermost joints, about half the length of the proximal one, with the last joint the largest. Posterior antennae comparatively feeble in structure, with the outer ramus rudimentary. Mandibular palp without any distinctly defined outer ramus, its place being occupied by a simple seta. Maxillae and maxillipeds scarcely different from those in the type species. Natatory legs, as in that species, well developed, with both rami distinctly 3-articulate, being in 1st pair of about equal size, in the succeeding pairs a little unequal, though less so than in the type species. Last pair of legs with the distal joint considerably pro- duced and of narrow linear form, carrying 5 comparatively small marginal setae, the proximal one of the outer edge rather remote from the others; proximal joint quite short, and not at all expanded inside, with only 2 small juxtaposed bristles on the hind margin. Male somewhat smaller than female, and resembling it in the general shape of the body, being however easily recognised by the more strongly built and distinctly hinged anterior antennae. • Colour whitish pelluid. Length of adult female 0.83 mm. Remarks. — In its outward appearance this Copepod bears a general resemblance to the form described above as Leptocletodes debills, exhibiting a rather- similar slender and narrow shape of the body and a similar week consistency of the integuments. On a closer examination, however, the structure of the several appendages, and more particularly that of the natatory legs, is found to be esentially different, and on the whole perfectly agreeing with that in Argestes mollis, with which species it accordingly must be assosiated in the same genus. Occurrence. — 1 have only met with this form in a single locality on the Norwegian coast, viz., at Riser, where some few specimens were taken from the considerable depth of 60 — 80 fathoms, muddy bottom. Gen. Euterpina, Norman, 1903. Syn: Euterpe, Clans (not Swainson). Generic Characters. ^Body subpyriform in shape, with no very sharply marked limit between the anterior and posterior divisions. Cephalic segment lar^e and acutely produced in front, Urosome comparatively small, with the 97 caudal rami not much produced, setae of the latter reduced in number. Anterior antennas in female of moderate size, and clothed with scattered simple setae; those in male much larger and very strongly hinged. Posterior antennae with the outer ramus well defined, though only composed of a single joint. Mandi- bles rather coarse, with the palp distinctly biramous. Maxillae without any distinctly defined exopodal and epipodal lobes. Anterior maxillipeds with 3 well defined setiferous lobes inside the basal part. Posterior maxillipeds ex- tremely slender and narrow. 1st pair of legs with both rami short, biarticulate* the 3 succeeding pairs with the rami distinctly 3-articulate, but of rather unequal size. Last pair of legs represented by two undivided juxtaposed plates, which in male are coalesced in the middle. Remarks. — As the name Euterpe, originally assigned to this genus by Glaus, had been preoccupied in Entomology, the above slight change of the name has been proposed by the Canon Norman. The genus is somewhat allied to Tachidius, differing however in some particulars rather markedly, especially as regards the structure of the posterior maxillipeds and the 1st pair of legs. It comprises as yet only a single species, to be described below. 78. Euterpina acutifrons, (Dana). (PI. LXVIII). Harpacticus? acutifrons, Dana, Crustacea of the Un. St. Expedition, p. 1192, PI. 83, figs. 11 a — b. Syn: Euterpe gracilis, Glaus. Specific Characters. —Female. Body comparatively slender, with the anterior division conspicuously broader than the posterior and evenly vaulted above. CephaHc segment occupying about half the length of the anterior division, and gradually exserted in front to a greatly prominent rostral pro- minence, acute at the tip. Lateral parts of the succeeding segments not expanded. Last trunkal segment much smaller than the preceding one. Uro- some not nearly attaining half the length of the anterior division and rather narrow, tapered distally, with the segments minutely denticulated at the hind edges; genital segment about the length of the 2 succeeding segments combined and imperfectly subdivided beyond the middle; last segment scarcely shorter than the preceding one, with the anal opercle finely denticulated at the edge. Caudal rami only slightly longer than they are broad and not at all divergent, each ramus provided near the base with a small subdorsal bristle and at the transversely truncated extremity with 2 rather strong setae of unequal length. Anterior antenna? about half -as long as the cephalic segment and rather narrow, 98 being composed of 7 well defined joints not much different in size, the terminal one however rather smaller than the others. Posterior antennae with the basal part distinctly subdivided, terminal joint with the spines and setae rather slender; outer ramus provided with 4 subequal ciliated setae. Posterior maxilliped with the hand scarcely at all dilated and about of same size and appearance as the basal joint, dactylus extremely slender, with scattered long hairs inside. 1st pair of legs rather small, and provided with the usual deflexed spine at the inner corner of the 2nd basal joint; rami of about equal size, with the distal joint somewhat larger than the proximal one. The 3 succeeding pairs of legs with the outer ramus rather strongly built and densely fringed outside with small spinules, spines attached to this ramus unusually coarse, 3 of them issuing close together from the end of the terminal joint; inner ramus shorter and much narrower than the outer. Last pair of legs consisting of 2 juxta- posed oblong quadrangular plates, contiguous at the base and fringed inside and at the end with short cilia, each plate having outside, at some distance from the base, a slender bristle and moreover 5 comparatively short and finely denticulated spines, one of them attached to the outer edge in about the middle, the other 4 to the transversely truncated end. Ovisac of moderate size and globular in form. Male of about same size as female, and not very different in the shape of the body. Anterior antennae however much more strongly built and pronouncedly hinged, being apparently only composed of 5 joints, the penulti- mate of which is very large and tumid, sub-pyriform in shape; terminal joint forming a slender and very mobile claw-like dactylus. Posterior antennae with one of the setae attached to the outer ramus much stronger than the others, almost claw-shaped. 1st pair of legs differing somewhat from those in the female in the shape of the inner ramus, the proximal joint of which is com- paratively more produced and forming with the distal one an abrupt geniculate bend. Last pair of legs rather unlike those in female, being represented by a single median plate, divided at the end by a short incision into 2 small lobules, each carrying 2 short spines. Genital lobes rather prominent, each armed with 2 coarse spines. Body in both sexes pellucid, without any conspicuous pigmentation. Eye in preserved specimens inconspicuous, but well observable in the living animal, and of a light red colour. Length of adult female reaching 0.67 mm. Remarks.— This form has by most anthors been recorded under the name Euterpe gracilis given to it by Glaus; but there cannot be any doubt 99 • that Giesbrecht was right in identifying it with the species previously recorded by Dana as Harpacticus acutifrons. It is an easily recognisable form, dif- fering also markedly in habits from most other Harpacticoida, being a true pelagic animal. Occurrence. — Some specimens of this widely distributed Copepod were found in a plankton-sample taken in the Skaggerak, about midways between the Norwegian coast and Skagen, and this occurrence may justify the reception of the present form within the Fauna of Norway. Distribution.— Norih Sea (at Helgoland), Atlantic Ocean, Mediter- ranean, Indian Ocean. Fam. Clytemnestridae. Remarks. — This family has recently been established by A. Scott, to include the genus Clynemnestra of Dana, which indeed in several points differs so markedly from the other Harpacticoida, that it scarcely can find its place in any of the other families of that division. No other genus referable to this family is as yet known. Gen. Clytemnestra, Dana, 1852. Syn: Goniopelte, Glaus. Goniopsyllus, Brady. Generic Characters. — Body more or less slender, tapering distally, with the anterior division conspicuously depressed, its segments, except the last one, being lamellarly expanded and projecting laterally to prominent triangular lappets. Cephalic segment very large, clypeiform, and produced in front to a well defined rostral prominence. Urosome much narrower than the anterior division, and sub-cylindrical in form. Caudal rami comparatively short, with the apical setae much reduced in size. Anterior antennae slender and attenuated, composed of 7 or 8 joints; those in male imperfectly hinged. Posterior antennae with the outer ramus replaced by one or 2 setae. Mandibles very small, with the masticatory part narrowly exserted and the palp obsolete. Maxillae much reduced. Anterior maxillipeds with only a single setiferous lobe inside the basal part. Posterior maxillipeds very slender, with the basal part 100 much produced; hand in female scarcely at all dilated, with the dactylus very small, in male somewhat more strongly developed. Natatory legs slender, with the inner ramus in all of them 3-articulate and longer than the outer, the later in 1st pair uniarticulate, in the succeeding pairs 3-articulate. Last pair of legs forming each a narrow biarticulate stem extended somewhat laterally. Remarks.— The present genus was established by Dana in the year 1852, to include a peculiar Copepod found in the Pacific. Neither Glaus nor Brady recognised Dana's genus, and the generic names proposed by these authors, Goniopelte and Goniopsyllus, are indeed only synonyms of that genus. The species of the present genus are readily recognised by the peculiar flat- tened and laciniate shape of the anterior part of the body, caused by the lamellar expansions of the segments, as also by the very short caudal setas. Of the structural details may be noted the poor development of the oral parts, and the rather anomalous structure of the legs, especially that of the 1st and last pairs. The genus comprises as yet only 2 nearly-allied species, both truly pelagic in habits. One of these species has proved to be referable to the Fauna of Norway, and will be described below. 79. Clytemnestra scuiellata, Dana. (PI. LXIX). Clytemnestra scutellata, Dana, Crustacea of the U. S. Explor. Expedition, p, 1194, PI. 83. Syn: Goniopelte gracilis, Claus. Specific Characters. — Female. Body moderately slender and rapidly tapered behind, with the anterior division conspicuously expanded and some- what flattened. Cephalic segment very large and broad, fully occupying half the length of the anterior division, with the postero-lateral corners triangularly produced; rostral projection rather prominent and obtusely pointed at the end. The 3 succeeding segments successively somewhat diminishing in size, each produced laterally to a prominent triangular lappet pointing obliquely back- wards. Last trunkal segment very small, without any lateral expansions. Uro- some scarcely attaining half the length of the anterior division and of narrow cylindrical form, though a little tapering in its outermost part; genital segment comparatively large and not subdivided in the middle; last segment about the size of the preceding one and transversely truncated at the end, with the anal opercle very small. Caudal rami fully twice as long as they are broad and somewhat incurved, with the outer distal corner conically produced; outer edge with 2 successive slender spines near the base and a short seta close to the 101 end; dorsal seta likewise attached near the end; apical setae 3 in number, the innermost very small, the middle one the longest, though only slightly exceeding the ramus in length. Anterior antennae very slender and attenuated, exceeding somewhat in length the cephalic segment,^and composed of 8 well defined joints clothed with scattered comparatively short setae, each antenna carrying more- over 5 well developed aesthetasks, one attached in the middle of the 4th joint, 2 to the end of the 5th joint, and 2 to the tip of the very slender terminal joint. Posterior antennae with the basal part- distinctly subdivided, terminal joint comparatively narrow, with the number of spines and setae reduced; outer ramus replaced by 2 juxtaposed ciliated setae of equal length. 1st pair of legs wanting the usual spine inside the 2nd basal joint; outer ramus imperfectly developed, only consisting of a single narrow linear joint, not even extending to the middle of the 2nd joint of the inner, and without any spines outside. The 3 succeeding pairs of legs with the 2nd basal joint bent outwards at an angle with the 1st; both rami distinctly triarticulate and very narrow, the inner one being the longer; 1st joint of outer ramus nearly as long as the other 2 combined and in 2nd pair wanting the usual spine outside. Last pair of legs with the distal joint about 3 times as long as the proximal one and very narrow, carrying 6 slender marginal setae, 2 on the outer edge and 4 on the apex. Colour (according to Giesbrecht) whitish grey, with a slight rosy tinge. Length of the specimen examined 1.24 mm. Remarks. — This is the species first described, and may accordingly be considered as the type of the present genus. It is closely allied to the form recorded by Brady from the Challenger Expedition under the name of Qonio- psylliis rostratus, which, as stated by Giesbrecht, is another species of the same genus, differing from the one here described in the comparatively shorter caudal rami, as also somewhat in the structure of the antennae. In Brady's species the anterior ones are only composed of 7 joints, and the posterior one have only a single seta in the place of the outer ramus. Occurrence. — A solitary female specimen of the present form was found in a sample taken, many years ago, in the upper part of the Christiania Fjord. This is the only instance of the occurrence of the present form off the coasts of Norway. I have never met with it subsequently. Distribution. — Irish Sea, Atlantic Ocean, Mediterranean, Gulf of Guinea, Indian and Pacific Oceans. 15 — Crustacea. CYCLOPOIDA. 6nathostoma. Fam. Cyclopinidae. Gen. Cyclopina, Glaus. Remarks.— On a careful examination of numerous specimens of Cyclo- pina taken in many different places of our coast, I am led to the conclusion that several nearly-allied species have hitherto been confounded, some of them agreeing more closely with C. gracilis Glaus, some others with C. longicornis Boeck. The supposed variability in the 2 said species of the caudal rami I am now not prepared to admit. In all other known Copepoda these appen- dages exhibit a perfectly constant appearance both as to form and relative size, and indeed furnish one of the best and most reliable characters for distinguishing nearly allied species. This I believe also applies to the species of the genus Cyclopina. If therefore any peculiarity in the structure of these appendages is found, this ought in my opinion to be regarded as an infallible indication of specific difference, unless quite gradual transitions could be stated to occur. But, according to my recent investigations, such transitions do not in reality exist. I have already in Vol. VI recorded 2 species closely agreeing with C. gracilis in the structure of the several appendages, but easily recognis- able by the different appearance of the caudal rami, and I now propose to distinguish 4 other species, 2 of which are likewise closely allied to that species, whereas the other 2 approash nearest to C. longicornis. 80. Cyclopina norvegica, Boeck. (PI. LXIX. Fig. 1). Cyclopina norvegica, Boeck, Oversigt over de ved Norges Kyster iagttagne Copepoder. Chr. Vid. Selsk. Forhandl. 1864, p. 247. Syn: Cyclops salinus, Brady. Specific Characters. — Female. Body resembling in shape that of C. gracilis, but of rather inferior size, and having the anterior division more 103 regularly oval in form, with the cephalic segment less contracted in front. Tail comparatively slender, with the genital segment about as long as the 3 suc- ceeding segments combined and very slightly dilated in its anterior part. Caudal rami much shorter than in C. gracilis, only slightly exceeding in length the anal segment, and scarcely more than 3 times as long as they are broad; seta of outer edge attached near the middle; innermost apical seta about twice as long as the outermost. Antennae, oral parts, and natatory legs of a structure very similar to that in C. gracilis. Last pair of legs likewise built on the same type as in that species, though, on a closer comparison, exhibiting slight differences in their form, the distal joint being more elongate and more strongly constricted at the base, with the outer apical spine fully twice as long as the inner. Ovisacs of moderate size and closely appressed to the sides of the tail. Colour uniformly whitish grey. Length of adult female scarcely exceeding 0.50 mm. Remarks. — The above described form is unquestionably that briefly announced by Boeck under the name of C. norvegica and also observed by several other authors, but regarded by them as identical with C. gracilis Claus. The latter species, originally described from the Mediterranean, has also been found by the present author on the Norwegian coast, and is figured in Vol. VI, PI. IV. Occurrence. — This is a pronouncedly littoral form, being only found close to the shores and frequently occurring in shallow pools left by the tide. I have met with it in many places, both of our southern and westeren coasts. Distribution. — British Isles, bay of Kiel, coast of France, Polar Sea. 81. Cyclopina brachystylis, n. sp. (PI. LXX; Fig. 2). Specific Characters. — Female. Body comparatively short and stout, with the anterior division broadly oval in form, greatest width occurring some- what behind the middle. Tail comparatively less slender than in the preceding species, with the genital segment scarcely longer than the 2 succeeding ones combined. Caudal rami very short, not even attaining the length of the anal segment and only sligthly longer than they are broad; seta of outer edge attached about in the middle; apical setae of moderate length, the innermost one a little longer than the outermost. Anterior antennae comparatively short and, as in the preceding species, only composed of 10 joints, the 6th of which is much the longest, though scarcely attaining the length of the 4 succeeding 104 joints combined. Last pair of legs resembling somewhat in shape those in the preceding species, but with the proximal joint comparatively less broad and the apical spines more unequal in length. Ovisacs very small and closely appressed to the sides of the tail. Colour, as stated in a specimen recently taken at Sandefjord, pale yellowish grey with slight darker yellow shadows; anterior antenna partly tinged with orange. Length of adult female scarcely exceeding 0.56 mm. Remarks. — By the very short caudal rami this form has a certain resemblance to C Schnelderl Scott (= C brevifiirca G. O. Sars), and may indeed on this account easely be confounded with that species. It is however much inferior in size, and moreover well distinguished by the structure of the anterior antennae, which are comparatively shorter and, as in the preceding species, only composed of 10 joints, whereas these antennae in C. Schneiderl are distinctly 12-articulate. The general form of the body also is somewhat different in the two species. Occurrence.— \ have met with this form in several places, both on the southern and western coast of our country, and northwards at least to the Trondhjem Fjord (Bejan). It is found in moderate depths, from 10 to 50 fathoms, but never in the littoral zone. 82. Cyclopina littorah's, Brady. (PI. LXIX, fig. 3). Cyclopina Uttoralis, Brady, Nat. Hist. Trans. Northumberland and Durham, Vol. IV, p. 429. PI. XVII, figs 9—14. Specific Characters. — Female. Body comparatively slender, resembling in shape that of C. longicornis, but rather inferior in size. Tail, including the caudal rami, about the length of the cephalic segment and sligthly attenuated behind. Caudal rami much shorter than in C, longicornis, not nearly attaining the length of the 2 preceding segments combined, and scarcely more than 4 times as long as they are broad; seta of outer edge attached about in the middle; innermost apical seta more than twice as long as the outermost. Antennae, oral parts, and natatory legs of a structure very similar to that in C. longicornis. Last pair of legs, as in that species, composed of 3 well defined joints, the middle one rather large, with the outer corner conically produced and tipped with a long seta; terminal joint comparatively small and 1Q5 broadly rounded at the end, which carries 4 ciliated setae, the innermost of which is the shortest. Ovisacs of moderate size and slightly divergent. Body of a clear whitish colour and partly ornamented with a fine rosy pigment.^) Length of adult female scarcely exceeding 0.65 mm. Remarks.— li is possible that the form observed by Boeck more pro- perly may be referable to the present species. In this cas should consequently in strict law the form described in Vol. VI as C. longicornis Boeck have a new name. I think however it may be allowed to retain both these names in the sense here proposed. The 2 species are certainly very nearly allied, but may at once be distinguished by the different length of the caudal rami. I have failed to detect any transition in this respect. Occurrence. — The species occurs along our whole southern and western coast, from the Christiania Fjord at least to Molde. It is always found close to the shores among algae and sometimes, as stated by Brady, even in pools left by the tide, never, as is the cas with C. longicornis, at any consider- able depth. Distribution.— Bniish Isles (Brady), Mediterranean (Giesbrecht). 83. Cyclopina dilatata, n. sp. (PI. LXX, fig. 1). Specific Characters.— female. Body rather short and stout, with the anterior division unusually dilated and, viewed dorsally, of rounded oval form. Cephalic segment very large, about twice as long as the remaining part of the trunk, and quite evenly rounded in front. Tail comparatively narrow, and occupying nearly half the length of the body; genital segment about equalling in length the 2 succeeding segments combined and sligtly widening in front. Caudal rami resembling in shape and relative length those in C. littoralis; seta of outer edge, however, attached somewhat in front of the middle. Anterior antennae comparatively shorter and less attenuated than in the said species, but composed of 19 well defined joints clothed with comparatively short setae. Posterior antennae, oral parts, and natatory legs apparently of a structure similar to that in C. littoralis. Last pair of legs however, though built on the same type, of a somewhat different appearance, the terminal joint *) The colour as signed (in Vol. VI) to C. longicornis, applies in reality only to the present species. C. longicornis is of a much paler hue. 106 being of rather larger size, fully as long as the other 2 combined, and obliquely rounded at the end. Ovisacs wanting in the specimens examined. Colour of the living animal not yet ascertained. Length of adult female 0.56 mm. Remarks. —This form also is nearly allied to C. longlcomis, but may at once be distinguished both from this and the other known species by the unusually broad and expanded anterior division of the body. The structure of the anterior antennae and of the last pair of legs is also somewhat different. Occurrence. — Two female specimens only of this form have as yet come under my notice. They were both found in a sample taken at Kors- havn from a depth of about 40 fathoms. Fam. Cyclopidae. Gen. Euryte, Philippi. 84. Euryte minor, Scott. (PI. LXX, fig. 2). Eiiryie longicauda, var. minor, Scott, Twenty-third Annual Report of the Fishery Board for Scotland, Part III, p. 143, PI. X, figs 13, 14. Specific Characters.— Female. Very like E. longicauda Philippi, but rather inferior in size and of somewhat more slender form of the body. An- terior division, seen dorsally, rounded oval in outline, with the cephalic segment very large and broadly rounded in front. Rostrum strong and abruptly recurved. Tail including the last trunkal segment, occupying about half the length of the body; genital segment somewhat less broad than in E. longicauda, but, as in that species, armed on each side in the middle with a strong dentiform projection curving backwards; anal segment scarcely longer than the preceding one. Caudal rami resembling in shape those in E. longicauda, being rather narrow and elongated, diverging somewhat in their outer part. Antennae oral parts, and legs of a structure very similar to that in the type species. Ovisacs narrow oblong in form, and somewhat less strongly divergent than in E. longicauda. Male of smaller size than female and a little more slender of form, with the cephalic segment less broad in front and the tail composed of 107 5 well defined segments. Genital segment considerably dilated, almost quadrate in form, and, as a rule, containing on each side an oblong oval spermatophore. Caudal rami comparatively shorter than in female. Anterior antennae very strongly hinged. Colour whitish grey, with a very slight pale yellow tinge. Length of adult female scarcely attaining 1 mm.; that of male 0.78 mm. Remarks. — This form was considered by Scott and also "by myself as only a variety of E. longicaiida. I am however now of opinion that it should more properly be regarded as a separate, though closely allied species. Occurrence. — I have met with this form in many different places of our coast, and have always found its characters constant. It is, unlike E. longi- couda, a true deep-water form, occurring in depths ranging from 20 to 50 fathoms, never in the littoral zone. Distribution. — Scottish coast (Scott). Siphonostoma. Fam. Ascomyzontidae. Gen. Rhynchomyzon, Giesbr. 85. Rhynchomyzon faico, Giesbr. (PI. LXXI). Rhynchomyzon falco, Giesbreclit, Die Asterocheriden des Golfes von Neapel, p. 102, PI. 5, figs. 28—40. Specific Characters. — Male. Body comparatively robuste, with the anterior division rather broad in the middle and somewhat depressed. Cephalic segment very large, about twice as long as the remaining part of the trunk, and, seen dorsally, triangular in outline, being gradually contracted anteriorly, with the extremity narrowly truncated; lateral corners slightly produced, biden- tate. Rostrum very strong, falciform, and curved downwards. The 3 suc- ceeding segments, like the cephalic segment, somewhat raised dorsally at the hind edge, and having the lateral corners produced to triangular recurved lappets. Last trunkal segment, as usual, much smaller than the preceding ones, 106 and slightly produced on each side. Tail comparatively short, not attaining half the length of the anterior division, and composed of 5 segments, the 1st (genital) of which is broadly quadrangular in form and provided at the hind corners with 2 juxtaposed setae of unequal length; each of the 2 succeeding segments produced laterally to acute triangular lappets curved backwards; the last 2 segments firmly connected and without any lateral projections. Caudal rami comparatively short, being only slightly longer than they are broad, and somewhat divergent; apical setae not much elongated. Anterior antennae not nearly attaining the length of the cephalic segment, and scarcely at all hinged, being composed of 17 joints, the 1st of which is much the largest, the 9th imperfectly subdivided in the middle; proximal half of the antenna somewhat thickened and clothed in front with scattered rather strong spiniform setae, carrying moreover 8 very slender recurved aesthetasks; penultimate joint with a single such aesthetask behind near the end. Posterior antennae resembling in structure those in the 2 other known species. Oral cone, as in R. pur- purotinctiim, very massive and prominent, but not prolonged in any true siphon al tube. Mandibles rather strong, pronouncedly cultriform, and finely denticulated inside the extremity; palp very small. Maxillae, maxillipeds and natatory legs of the usual structure. Last pair of legs extremely small, biarticulate. Colour of the living animal not yet ascertained. Length of the specimen examined 1.25 mm. Remarks. — I think I am right in determining the above-described remark- able form as the hitherto unknown male of R. falco Giesbrecht. It may easily be recognised from the other 2 Norwegian species described in Vol. VI by the robust form of the body, by the strongly marked armature of the seg- ments, and by the comparatively short caudal rami. Occurrence. — The solitary specimen obtained was found in a sample taken at Riser from a depth of about 30 fathoms. Distribution.— QuW of Naples (Giesbrecht). 109 Fam. Acontiophoridae. Gen. Acontiophorus, Brady. 86. Acontiophorus ornatus, Brady. (PI. LXXII). Ascomyzon omatiim. Brady & Robertson, British Assoc. Report p. 197. Specific Characters. — Female. Body on the whole of a more robust appearance than in A. scutatus, with the anterior division broadly oval in form and somewhat depressed, greatest width considerably exceeding half the length and occurring behind the middle. Cephalic segment very large, nearly twice the length of the trunk, and narrowly rounded in front, lateral corners slightly produced. The 3 succeeding segments comparatively broad, with the epimeral plates somewhat expanded an distinctly angular behind. Last trunkal segment very small. Tail slightly exceeding in length Vs of the anterior division; genital segment about occupying half the length of the tail and almost of equal width throughout, lateral corners of this and the succeeding segment acutely produced behind. Caudal rami comparatively short, being scarcely longer than they are broad; apical setae well developed 9nd partly finely plumose. Anterior antennae much more slender and elongated than in A. scutatus, and composed of 16 well defined joints, the 3rd of vhich is much the largest; proximal part of the antenna only slightly dilated and clothed with strong partly ciliated setae. Posterior antennae likewise comparatively more slender than in the type species, though of rather similar structure. Siphonal tube scarcely extending beyond the anterior division of the body. Oral appendages and natatory legs on the whole built on the same type as in A. scutatus. Last pair of legs, however, af comparatively larger size, with the proximal joint very broad, lamellar, and irregularly indented behind; distal joint oval in form and provided with 5 ciliated setae of about equal length. Colour of the living animal not yet ascertained. Length of adult female 1.03 mm. Remarks. — This form was at first recorded by Brady and Robertson under the name of Ascomyzon ornatus, and was subsequently redescribed and figured by the first-named author in his well-known Monograph as Acontio- phorus armatus. As however the specific name ornatus is the older one; it must be retained for the present form. The differences between this species and A. scutatus are very pronounced, and at first I therefore believed them to 16 - Crustacea no be of generic value. I am however now disposed to include both species in the same genus. Occurrence.— k solitary female specimen only of this pretty form has as yet come under my notice. It was found in a sample taken at Riser in about the same place, where Rliyncomyzon falco occurred. Distribution.— Briiish Isles (Brady), Mediterranean (Giesbrecht). Poecilostoma. Fam. Lichomolgidae. Gen. Hermannella, Canu. 87. Hermannella dubia, n. sp. (PI. LXXIII, fig. 1). Specific Characters. — Male. Anterior division of body rather broad, sub-depressed, seen dorsally broadly oval in outline, with the greatest width equalling -/a of the length and occurring in front of the middle. Cephalic segment very large, fully twice as long at the 3 succeeding segments com- bined, and evenly rounded in front, exhibiting behind the middle a well- marked transverse suture. Last trunkal segment very small. Tail about equalling in length ^/a of the anterior division, and composed of 5 well defined seg- ments, the 1st of which (the genital segment) is very large and expanded, almost circular in outline, exhibiting on each side a roomy chamber for the reception of the spermatophores; the remaining segments narrow cylindrical in form, the last being the largest. Caudal rami about 3 times as long as they are broad and scarcely at all divergent; seta of outer edge attached in the middle; apical setae partly brocken in the specimen examined, but appar- ently normal. Anterior antennae less slender than in the other known species, scarcely exceeding half the length of the cephalic segment, and only composed of 6 joints. Posterior antennae not very strong, and composed of 4 well-defined joints, the 2nd of which is the largest; 3rd joint armed at the end anteriorly with a hook-like spine accompanied proximally by 2 small bristles; last joint of about same size and provided at the tio with 4 curved claws, 2 of which Ill are distinctly jointed in the middle; outside the latter a slender curved seta is attached. Maxillae with the masticatory lappet fusiform in shape and exserted to a very long and narrow setiform lash, inner edge armed with about 8 strong curved denticles, outer edge ciliated; palp of the usual appearance. Anterior maxillipeds with the distal joint gradually tapered and provided inside with a stout spine, terminal proces only slightly curved and armed outside with 4 — 5 unusually slender spinules. Posterior maxillipeds exhibiting the structure usual for male specimens. The 3 anterior pairs of natatory legs on the whole of normal appearance, with the rami comparatively broad and subequal in size; 4th pair however distinguished by the want of the outer-edge spines on the outer ramus, inner ramus scarcely narrower than the outer and having 2 setae inside the midle joint, terminal joint with 3 unusually slender spines at the end and with the inner edge smooth. Last pair of legs with the free joint narrow linear in form and carrying at the tip a slender spine and a some- what shorter seta, inner distal corner produced to a well-marked dentiform projection. Colour of the living animal not yet ascertained. Length of the specimen examined 0.70 mm. Remarks. — The above-described form cannot be referred to any of the hitherto known species, differing, as it does, conspicuously by the comparatively short 6-articulate anterior antennae, as also by the structure of the posterior antennae and that of the 4th pair of legs. In the broadly expanded anterior division of the body it somewhat resembles H. vallda G. O. Sars, but is otherwise very different from that species Occurrence. — The solitary male specimen obtained was found in a sample taken by Mr. Kjaer at Drebak from a depth of about 50 fathoms. Gen. Lichomolgeila, G. O. Sars. 88. Lichomolgeila pusilla, G. O. Sars. (PI. LXXIII, fig. 2). See: Vol. VI, p. 216, PI. CXVIII, fig. 1. Remarks. — This dwarfed form has been described and figured in Vol. VI from a solitary specimen taken at Skutesnaes, S. W. coast of Norway. On the accompanying plate I give new habitus-figures with some details of another specimen obtained on the south coast, at Lillesand. As seen from the figure, the lateral view of the body is rather characteristic by the unusually deep 112_ and boldly vaulted cephalic segment giving the animal in that situation a very extraneous appearance. The specimen, though fully adult, did not exceed a length of 0.40 mm. Gen. Pseudomolgus, G. O. Sars. 89. Pseudomolgus arenicola, Brady. (PI. LXXIV). Lichomolgus aienicolus, Brady, Monogr. of British Copepoda, Part ill, p, ^6, PI. LXXXVIII, figs 1—7. Specific Characters. — Female. General form of body very like that in P. leptostylis G. O. Sars^), though perhaps a little less slender, with the anterior division more regularly oval in outline, the greatest width occurring in the middle. Head very distinctly defined from the 1st trunkal segment and narrowly truncated at the extremity. Last trunkal segment remarkably narrow and elongated. Tail about equalling in length the head and 1st trunkal segment combined; genital segment fusiform in shape and distinctly subdivided in the middle by a transverse dorsal suture; anal segment only slightly longer than the preceding segment. Caudal rami much shorter than in P. leptostylis, not nearly attaining the length of the 2 preceding segments combined, and about of equal width throughout. Anterior antennae rather slender and, as in the 2 other species, composed of 7 joints, the somewhat oblique suture between the last 2 joint being distinctly marked. Posterior antennae very powerful, and agreeing both in form and armature with those in P. leptostylis. Anterior lip deeply insinuated in the middle. Maxillae with the 2 proximal denticles of the principal masticatory lappet somewhat lamellar in shape, their inner sharpened edge being divided into 3 or 4 fine spinules; palp of a somewhat irregular form, and having in the middle of the rounded extremity a well-marked narrow incision. Maxillipeds and legs almost exactly as in P. leptostylis. Body semipelluced, of a uniform whitish grey colour, with darker translucent ovaria. Eye well observable, with light reddish pigment. Length of the specimen examined L60 mm. Remarks. — I cannot doubt that the above-described form is identical with the British species recorded by Brady and by Scott, though the description- and figures given by those authors do not fully agree with those here given. The species is indeed still more closely, allied to P. leptostylis than I had 1) See Vol. VI, p. 182, PI. Clil. 113 formerly supposed by consulting the statements given by the said authors. Yet the species may at once be distinguished both from this and the other species (P. dilatatus) by the much shorter and stouter caudal rami. Occurrence.— X solitary fully adult female specimen of this form was taken last summer at Hvaler, outside the Christiania Fjord, from a depth of about 10 fathoms. Distribution. — British Isles (Brady, Scott). Fam. Sapphirinidae. Gen. Sapphirina, Thompson, 1829. Generic Characters. — Body more or less conspicuously depressed and rather unlike in the two sexes, that of male much broader than in female and blade-like, with the epimeral plates of both the anterior and posterior divisions lamellarly expanded, exhibiting moreover, in the living animal, a beautiful iridescent or opaline lustre. Head generally well defined from the 1st trunkal segment, and provided in front with 2 closely set cuticular lenses (conspicilla), behind which, as in Corycceus, at some distance 2 rod-like, pigmented strings occur, each terminating in a highly refractive body.^) Tail much narrower in female than in male, and in both sexes composed of 5 v^ell defined seg- ments. Caudal rami blade-like, with the marginal setae very small. Anterior antennae alike in the two sexes, and rather short, with the number of joints somewhat reduced. Posterior antennae distinctly prehensile, terminating in a short and stout claw. Oral parts built on the very same type as in the Lichomolgidce. Natatory legs »vell developed and more or less incurved, with both rami 3-articulate. Last pair of legs very small, uniarticulate, extended laterally. Remarks. — This genus was established by I. V. Thompson as early as the year 1829, when our knowledge of the marine Copepoda was still very imperfect. The species observed by that zoologist (S. indicator) cannot be identified; but it is evident that he has had before him male specimens of some species belonging to the present genus, the brillant iridescence of their bodies having at once attracted his attention. — The genus comprises numerous ') As to the significance of this apparatus, I may refer to the note given in Vol. VI, p. 195, 114 species, chiefly occurring in the equatorial parts of the Oceans, thougii some- times by currents thrown more or less out of their true home. They are all pronouncedly pelagic animals, being as a rule met with in the open sea, near the surface of the water. As is the case with the other poecilostomous Cyclopoida, they are semiparasitic in habits, the females being at times found within the pallial cavity of various pelagic Timlcata (Salpae, Pyrosoma etc.). More generally however they are taken free in the sea, and this is always the case with the males. 90. Sapphirina iris, Dana. (PI. LXXV & LXXVl). Sapphirina iris, Dana, United States Explor. Expedition, Crustacea, p. 1239, PI. 87, figs. 1 ad Syn: Sapphirina salpa-, Glaus. „ gemma, Brady (not Dana). Specific Characters. — Female. Body elongate, gradually tapered behind, with all the segments sharply marked off from each other. Head defined from the 1st trunkal segment by a distinct, somewhat flexuous suture, and obtusely rounded in front; conspicilla well marked and closely approximate. Epimeral plates of the 3 middle trunkal segments distinctly prominent and obtuse-angular behind. Last trunkal segment much smaller than the preceding ones, but well defined. Tail rather narrow, exceeding somewhat half the length of the anterior division, and composed of 5 sharply defined segments, the genital segment being distinctly subdivided in the middle; lateral corners of this and the 3 succeeding segments angular behind; anal segment exceeding in size the preceding segment and quadrangular in form. Caudal rami rather large, attaining the length of the 2 preceding segments cotribined, and oblong oval in outline, with the inner edge much more curved than the outer and slightly angular at the end; seta of outer edge attached about in the middle, dorsal seta placed much nearer the extremity. Anterior antennae comparatively short and stout, gradually tapered distally, being composed of 5 joints, the 2nd of which is much the largest, occupying about half the length of the antenna. Posterior antennae rather strong, with the terminal part (composed of the last 2 joints) much shorter than the pre- ceding joint; apical claw short and stout, accompanied in front by 2 small bristles. Natatory legs with both rami well developed and of nearly equal size. Last pair of legs represented on each side by a small conical joint tipped with 2 unequal bristles. Ovisacs very long and narrow, almost cylindric in shape, and containing numerous ova. 115 Male rather unlike the female in its outward appearance, the body being very thin, blad-like, and broadly oval in outline, with the epimeral plates of all the segments, except the last trunkal and the last caudal one, lamellarly expanded and closely contiguous. Last trunkal segment very small and almost wholly concealed by the neighbooring segments. Last caudal segment likewise much smaller than in female. Conspicilla less sharply marked, and somewhat remote from the frontal margin. Posterior maxillipeds, as usual, more fully developed than in female, with the apical claw long and slender. Body of female (according to Giesbrecht) of a somewhat opaque yellowish grey colour, with pale reddish ovaria and ovisacs; that of male highly pellucid and, in the living state, brillantly iridescent. Length of female attaining 7.40 mm.; that of male 7.10 mm. Remarks.— This is much the largest of the known species, and in the adult state it may thereby be easily recognised. In the general form of the body, however, as also in the structure of the several appendages it agrees very nearly with some of the other species, for instance S. gemma Dana, with which it was indeed identified by Brady. The S. salpce of Glaus is quite cer- tainly the present species. Occurrence.— Ih^ present form, it is true, has not yet been recorded from the Norwegian coast, nor have I myself ever met with it here. I think, however, that it notwithstanding ought to be included in the Norwegian fauna as an occasional visitor. For it not seldom happens that shoals of Salpce (S, runcinata, Chamissoj by heavy gales and currents are thrown from the open sea to certain points of our western coast, and, as the present copepod is a constant companion of Salpae, it is very likely to believe that it also in such cases has been associated with these pelagic Tunicata ^). The figures here given are drawn from specimens taken during the Monaco Expeditions in the North Atlantic Ocean. Distrihiilion. — North and South Atlantic, Mediterranean, Indian Ocean, Pacific. '), My iate father once witnessed such an influx of Salpc-e at Fieri), where he at that lime was settled as a pastor, and on a drawing made by him of a Saipa a parasit was indeed sl