CRUSTACEA MALACOSTRACA. Ill 29 



on the broad median dorsal surface. — The legs slender; first pair not prehensile and differing but 

 little from the second pair; the posterior pairs with seventh joint and the claw (fig. 2 f ) distinctly longer 

 and thinner than on the anterior pairs; the claw is somewhat or very long (figs. 2f and4c) and instead 

 of an accessory claw a couple of hairs. 



Abdomen about as broad as, or considerably broader than, long, and posteriorly truncate, with a 

 tooth or process at the end of each lateral margin. Operculum in the female (figs. 2I and4d) propor- 

 tionately small, broadly rounded posteriorly. — Median lamella of the male operculum (it is unknown 

 in H. armadilloides) broad a little from or at the base (figs. 2 h and 3 f), and tapering considerably to 

 somewhat from the end, its distal part is somewhat widened and peculiar in structure; the copulatory 

 organ of second pleopods produced into an extremely long thread (fig. 2I1, c\ fig. 3g). — Uropods very 

 small or nearly rudimentary, consisting of an oblong joint, and sometimes an exceedingly small proximal 

 joint can be discerned (fig. 2 1). 



Remarks. In his Account (p. 119) Sars says that Nannoniscus bicuspis G. O. S. "is scarcely 

 congeneric" with the type of the genus, N. oblougus G. O. Sars, and with N. caspius G. O. S., "differing, 

 as it does, considerably, in the structure of both the antennae and the oral parts, and also in that of 

 the caudal appendages." In 1908 Harriet Richardson established the genus Haploniscus with N. bicuspis 

 G. O. S. as the type, and described, besides, two new species. In 191 4 Vanhoffen added two antarctic 

 species. The "Ingolf" captured three species, two of them new. 



13. Haploniscus bicuspis G. O. Sars. 

 (PI. II, figs. 2 a— 2 1). 

 1877. Nannoniscus bicuspis G. O. Sars, Arch. f. Math, og Naturv. Vol. II, p. 352. 

 ! 1885. — G. O. Sars, North-Atl. Exp. p. 122; PI. 10, figs. 31—45. 



Description. Body rather depressed, in the female from two and a half to two and two- 

 third times as long as broad, in the male (fig. 2 a) about three times as long as broad. — Front margin 

 of the head nearly transverse with a minute protuberance at the middle (fig. 2 b). — The antennulae, 

 especially their two proximal joints, thicker in the male (fig. 2 b) than in the female (fig. 2 d), in both 

 sexes scarcely reaching the end of the penultimate joint in the antennal peduncles; flagellum in the 

 male 5-jointed, in the female 4-jointed. — Antennae somewhat less than half as long as the body; the 

 process on the third joint (figs. 2 b, 2 c, 2d) is robust, somewhat oblong-triangular, acute, projecting 

 upwards and a little or somewhat outwards from the middle of the upper surface of the joint; penul- 

 timate peduncular joint much thicker in the male (fig. 2 b) than in the female (fig. 2 d); last peduncular 

 joint without any tooth or process at the end; flagellum with 13 joints. 



The three posterior thoracic segments and the abdomen fused on the broad median part of the 

 dorsal surface (fig. 2 a); the limit between sixth and seventh segments generally perceptible, those 

 between fifth and sixth segments and between seventh segment and abdomen are only visible towards 

 the lateral margins. 



Abdomen in the female (fig. 2 1) a little broader than long, with the postero-lateral processes 

 only about one-third as long as the distance between them; uropods conspicuous, reaching to a little 



