\ MAI.ACOSTRACA. III. 



mrroiut Captured bv tin- "IiiRoir at a single station in the cold area. 

 South of Jan Mayen: Stat 113: Lat 69 e 3i' N., Long. 7o6' W-, 1309 fath.. temp. -4- it>; i pec. 



66. Nannoniscus affinis a sp. 

 (PI. X, figs. 3 a 3 c). 



Female (without marMipiuim. Closely allied to .V. sptnicornis and agreeing with it in most 

 features, above all in the antennulce, the shape of the antennal squama, and the anterior thoracic seg- 

 ments, thus in ini|H>rUiit character* separating JV. spinicornis and N. affinis from all other northern 

 species. It i* in reality sufficient to point out the three or four differences between N. affinis and 

 N. spinitornis. 



The keels on the head as in N. spinicornis without anteriorly protruding ends, and continued 

 in the convex anterior margin of the front area (fig. 3 a), but the keels converge considerably forwards. 

 so that the anterior margin of the area is much shorter than in .V. tpinic&rnu, being between one- 

 third and one-fourth of the breadth of the head. -- The ventral process on seventh thoracic segment 

 i fin- }o i.s much longer and stronger than in A', spinicornis. Thoracic legs -- first pair lost in the 

 main as in .V. r///<-0rj>, but the angle of fourth joint (fig. 3 b) terminates in a long, very strong, spini- 

 torm seta almost as long as the joint Operculum (fig. 3c) almost half as long again as broad, post- 

 eriorly conspicuously more produced than in M spinicornis, and terminating in a somewhat small, nearly 

 spiniform median process. 



Length of the largest specimen scarcely 1-3 mm. 



Remarks. It was only after some hesitation that I established N. a/finis as a species. I think, 

 however, that the differences pointed out between it and the preceding form will prove to be valid 

 specific characters; furthermore JV. affinis was secured at a pronounced warm-water station, while M 

 spinicornis was gathered at one of the deepest and most typical cold-water stations. 



Occurrence. Taken by the "Ingolf at a single station in the warm area. 



South-West of Iceland: StaL 78: Lat 6o37' N., Long. 2jS2' W., 799 fath.; temp. 4-5*; a'/, spec 

 (mutilated). 



Group IX. Desmosomatini. 



Body very oblong, moderately depressed. Head free; eyes wanting. Antennulsc dorsal, short, 

 with very few joints in the flagellum. Antennae moderately long, thicker in the males than in the 

 females; squama not perceptible. Mandibles with the incisive part, the movable lacinia, and the seUe 

 well or very moderately developed; the molar process reduced, rather short or short, tapering to the 

 narrow, setiferous end, and directed somewhat backwards; palp 3-jointed or wanting. Palp of the 

 maxillipeds nearly as in Nannoniscini ; epipod somewhat long. - Thoracic segments movable, divided 

 into two very different sections. The four anterior pain of thoracic legs inserted on the sides of the 

 segments, and at least second to fourth pairs with well developed epimera; first pur very different 



TW l^ITE.fiili. III. . 14 



