159 



than in the fonner species. The last juiut uf the maxillipeds and the terminal spine on the 

 pennltiniate joint in the specimen from B. Icevis are not very different from S. dispar, and 

 distally much less expanded than in the specimen from D. cornuta (fig. 4g), but this diiference 

 is scarcely of any value. The trunk is naked. The genital area, in botli specimens, is a 

 rather small, transverse plate of irregular shape, and for the most part very thin, which, in 

 the specimen from D. cornuta (fig. 4e) is about twice as broad as long, on the whole remin- 

 ding of a rectangle; in the specimen from D. Icevis (fig. 4d) it is comparatively a good deal 

 longer, somewhat heart-shaped, having a concave front margin, and an irregular, lobed 

 posterior margin; in both specimens the genital apertures are middle-sized, somewhat obliciue 

 and curved, anteriorly not far apart; the area is naked, caudal stylets wanting. (The 

 differences in the shape of the genital areas are indeed very consideiable, but in both spe- 

 cimens the plate is so irregularly shaped, so unsymmetrical and so feebly chitinised, that I 

 <1() not think its shape is of any importance; on the contrary, I expect that other specimens 

 of this species will exhibit other shapes of the plate. 



MALE. In proportion to the female, it almost exceeds medium size (fig. 4b : fig. 4a); 

 the specimen from D. Icevis (fig. 4b and fig. la — lb) is ■29 mm. long, the one from D. cornuta 

 (fig. Ic — Id) -31 mm. long. The specimen from D. Icevis is — seen from the side (fig. la) 

 — considerably thicker than the other specimen (fig. 1 d), however, this thickness seems to 

 be due to a swelling of the body which is scarcely normal. Otherwise there are no other 

 difterences between the two specimens than those wliich may be detected in comparing 

 fig. 1 b and fig. 1 c, viz. some slight deviations in the anterior part of the front and in the 

 hair-covering in front of the antennulse. — Seen from below, it bears great resemblance to 

 S. (JisjMir, but the greatest breadth of the body lies more backward, and it deviates especially 

 in the somewhat different shape of the fi-ont, and in the equipment of the maxillae and of 

 the sub-median skeleton. The distance from the antennulae to the narrowest part of the 

 frontal plate is shorter than in S. dispar; the expanded distal part is not circular, but 

 considerably broader than long, limited to the front by a regular arc, the third of a circle, 

 and decorated with processes as in S. dispar; the lateral angles are almost rectangular, 

 and posteriorly the dilated part is limited by oblique lines. From the base of this expansion, 

 backward along the lateral margin itself, runs a pretty good-sized keel (fig. 1 b, y), which is 

 also limited by an arc of a circle, and wliich is armed with setaceous processes similar to those 

 of the median expansion. In the middle of the ventral side of the expansion we find the 

 small cliitinous ring mentioned in the description of S. dispar, but in S. insignis the foui' 

 processes are prolonged and meet in the centre so as to form a cross within the ring. 

 Antennula;, mouth and maxillul* nearly as in S. dispar. Maxillae small; their basal joint 

 has on its posterior side proximally a row of tolerably small, rather clumsy, processes 

 directed backward, distally some much smaller processes; the third joint is well set ofi' and 

 acute. Basal joint of the maxillipeds scarcely as long as in »S'. dispar, its anterior side 

 furnished with several rows of haii's; the other joints nearly as in the preceding species. 



