



with rather plentifully. Indeed, in the Arctic Ocean they seem to reach their maximum 

 of development, the huge Dlastylis Goodsiri being more than an inch in length. 

 The occurrence of Cumacea in the Caspian Sea, as stated by the present author, 

 is of considerable interest. The fauna of this large basin also exhibits in other respects 

 a pronounced marine character, and undoubtedly has originally been derived from 

 the Ocean, when long ago an open communication existed. 



Of the 9 families into which the Cumacea are divided, all, except one. 

 the Vaunfhompsomidce, are represented in the fauna of Norway, and will be 

 treated of below. 



Fam. 1. Cumidae. 



Characters. Body in some cases rather short, in others very slender, 

 with no sharp demarcation between the anterior and posterior divisions. Carapace 

 comparatively large, with a distinct notch on each side below the pseudo-rostral 

 projection; the latter more or less distinct, in some cases wanting. 1st pedigerous 

 segment more or less concealed. Eye distinct or wanting. Superior antenna? 

 with the flagella very short, the inner one, as a rule, rudimentary. Inferior an- 

 tenna? in female very small, scale-like, biarticulate ; in male well developed, with 

 the flagellum filiform and composed of numerous, short articulations. Oral parts 

 normal. Branchial apparatus well developed, with the gill-elements leaf-like and 

 densely crowded together in a straight series. 3rd pair of maxillipeds generally 

 very large, with the joints more or less expanded. The 4 posterior pairs of legs in 

 both sexes simple, without natatory exopodites. Pleopoda in male present on all 

 the caudal segments except the last. Uropoda with the outer ramus biarticulate, 

 the inner uniarticulate or biarticulate. Telson wanting. 



Remark*. This family is prominently distinguished by the absence in 

 both sexes of natatory exopodites on the 4 posterior pairs of legs. The male, on 

 the other hand, is provided with 5 well-developed pleopoda, a number which is only 

 found in one of the other families, viz., the Vaimthompsoniidw. The family 

 as yet comprises 6 genera, viz., Cumci, Iphinoe, Cydaspis, Cyclaspoides, Cumopsis 

 and Stephanomma. Of these the first 3 are represented in the fauna of Norway, 

 and will be characterised below. 



2 Crustacea. 



