9 
with rather plentifully. Indeed, in the Arctic Ocean they seem to reach their maximum 
of development, the huge Diastylis Goodsiri being more than an inch in length. 
The occurrence of Cumacea in the Caspian Sea, as stated hy 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 Vaunthompsoniidee, 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 antennae 
with the flagella very short, the inner one, as a rule, rudimentary. Inferior an¬ 
tennae in female very small, scale-like, Inarticulate; 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 biartieulate, 
the inner uniarticulate or biartieulate. Telson wanting. 
Remarks. — 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 Vaunthompsoniidce. The family 
as yet comprises 6 genera, viz., Cuma, Ipliinoe, Cyclaspis, Cyclaspoides, Cumopsis 
and Stephanomma. Of these the first 3 are represented in the fauna of Norway, 
and will be characterised below. 
2 — Crustacea. 
