8 Gr. O. Sars. 



with minute denticles, the number of which varies in different 

 individuals. The lateral lobes of the carapace, flanking the 

 sinus, terminate each in an acute point. On each side of 

 the carapace the shell-gland is fairly distinct, extending from 

 the cervical sulcus obliquely backwards. As to structure, 

 the carapace is very thin and flexible, semipellucid, and 

 exhibits a perfectly smooth and polished surface. 



The exposed part of the body is very slender, cylindric, 

 and fully as long as the carapace, exceeding the median 

 length of that part by about V3 of its length. It comprises 

 about 30 segments, the 16 anterior of which more properly 

 belong to the trunk or mesosome, as they are provided with 

 legs. But no distinct bundary exists between these seg- 

 ments and the 14 posterior, non-pedigerous segments, which 

 represent the caudal part of the body or the tail. All these 

 segments are very sharply defined, and each provided above 

 with a transverse row of short spinules, this row, in the 

 caudal segments, being also continued on the ventral side. 

 The last segment (see figs. 5, 6) is considerably larger than 

 the preceding ones, equalling in length about 3 of them com- 

 bined, and it is quadrangular in form, and somewhat flattened. 

 It exhibits dorsally on each side a nodiform prominence 

 clothed with a few small spinules, and has at the base of 

 the caudal filaments outside a few somewhat larger spines. 

 The posterior edge of its dorsal face is transversely truncated, 

 without any trace of a caudal plate, and that of the ventral 

 face (see fig. 6) appears deeply emarginated; between them 

 the fleshy lips bounding the anal orifice are seen to project. 



The caudal filaments are not particularly long, scarcely 

 attaining half the length of the body, and are, as a rule, 

 but little divergent. On a closer examination, they are 

 found to consist of numerous short and rather regular 



