CRUSTACEA MALACOSTRACA. III. 



part extremely thickened, oblong-oval and as long as the four following slender joints combined (the 

 end of flagellum lost). 



Thoracic segments, excepting as to the breadth mentioned, nearly as in the female; the ventral 

 posterior protuberances scarcely as high as in that sex. - - The three posterior pairs of legs (fig. i a) 

 with about four long setae on the upper margin of fifth joint, and a good number of very or extremely 

 long setae on sixth joint. 



Abdomen posteriorly nearly as produced as in the female, but rather gradually (fig. 6 h), so 

 that the distal third of the lateral margins is flatly and feebly concave, while the end is more narrowly 

 rounded than in the female. Operculum conspicuously longer than broad; the median lamella a 

 little widened near the end, with the distal outer angle a little produced, triangular, while most of 

 the terminal part of the lamella constitutes a kind of rounded lobe, divided of course in the median 

 line. Uropods about as in the female, excepting that their peduncles are a little longer. 



Length 2-1 mm. 



Remarks. The female is instantly separated from all other species by the shape of the post- 

 erior part of abdomen, while the male may be distinguished by some features taken together: the 

 breadth of the frontal emargination, the somewhat short antennal squama, the shape of the abdomen 

 and of the median lamella of the operculum. 



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



Davis Strait: Stat. 24: Lat. 63o6' N., Long. 56oo' W., 1199 fath., temp. 3-4; numerous spec. 



(16 # and at least 50 $). 



58. Nannoniscus laticeps n. sp. 

 (PI. IX, figs. 3 a- 3 d). 



Young Female (with seventh pair of legs not fully developed). -- Body (fig. 3 a) about three 

 and a half times as long as broad. Head and the two anterior segments about two-thirds as broad 

 again as sixth segment and abdomen; third segment not much narrower than the second, and some- 

 what broader than the fourth, which has its lateral margins converging extremely backwards. 



Head (fig. 3 b) fives times as broad as the distance between the anterior ends of the cephalic 

 keels, and the anterior margin of the front area slightly concave. Antennulae (fig. 3 c) with first 

 joint a little longer than broad; second joint distinctly longer than the first, somewhat thick, with the 

 terminal protuberances rather short; the process from fourth joint reaches conspicuously beyond the 

 middle of the uncommonly small, oblong vesicle. Antennal squama marked off, short, much shorter 

 than the diameter of third peduncular joint. 



Antero-lateral angles of second segment terminate in distinct spines (fig. 3 b), while the angles 

 of first and third segments terminate in fine setae. The posterior median part of the ventral side 

 considerably vaulted. 



Abdomen (figs. 3 a and 3 d) conspicuously longer than broad, posteriorly very broadly rounded, 

 and the lateral margins nearly parallel. -- Operculum somewhat longer than broad, with the posterior 

 margin considerably convex and, besides, almost angular, as a small median part is feebly produced; 

 a spiniform, moderately small process projects on the ventral surface somewhat near the base, and at 



