30 G. 0. SARS. CRUSTACEA. [norw. POL. EXP. 



The 2 anterior pairs of pereiopoda (figs. % 3) are quite normal in 

 structure. 



The 3 posterior pairs (figs. 4, 5, 6) are, however, distinguished by the 

 large size of the basal joint, as compared with the terminal part. The 

 last pair (fig. 6) especially, look rather different from those in the other 

 known species, being considerably shorter than the preceding pair, with the 

 terminal part not exceeding even half the length of the basal joint. The 

 latter is very large, laminar, and oblong quadrangular in form, with the 

 infero-posteal corner produced to an obtusely rounded lobe. The posterior 

 edge of this joint in all 3 pairs is coarsely serrate throughout. 



The branchial lamellae (see figs. 1 — 5) are rather large, but quite simple 

 in structure, without any lateral lobes. They are wanting on the last pair 

 of legs (fig. 6). 



The 2 anterior pairs of uropoda (figs. 9, 10) have the rami quite simple, 

 and mucronate, whereas in the type species, as shown by the present author, 

 the inner ramus of the 2nd pair is pecuHarly transformed. 



The last pair of uropoda (see figs. 8, 11) are comparatively short, scarcely 

 reaching beyond the others. In structure they resemble those in the type 

 species, both I'ami, but especially the outer one, being fringed with ciliated 

 setae in addition to the spinules. 



The telson (see figs. 8, 12) is rather large, laminar, and reaches to about 

 the end of the basal part of the last pair of uropoda. It is rounded 

 quadrangular in form, and sUghtly narrowed distally, with the terminal edge 

 distinctly insinuated in the middle, and armed on each side with a minute 

 denticle. 



Occurrence. Some adult specimens of this form, chiefly of the male 

 sex, were collected during the months March and April, 1894, in about 80^ 

 latitude, north of the New Siberian Islands. The specimens seem not to 

 have been taken by the aid of the tow-net, but on bait hung down from 

 the ship. Moreover, some young specimens of this species occurred in 

 a sample taken on the 4th February, 1896, and much farther west, near the 

 85th degree of latitude. 



