59_ 



epimeral parts of last segment scarcely produced behind. Tail (exclusive of the 

 terminal appendages) about the length of the anterior division, segments simple, 

 unarmed. Eye fairly well observable and somewhat convex. Superior antennae 

 of moderate length, the peduncle reaching somewhat beyond the tip of the pseu- 

 dorostral projection, its 1st joint about the length of the other 2 combined. 

 First pair of legs a little longer than the carapace, basal joint densely fringed 

 with setae and slightly spinulous in its distal part, the last 3 joints scarcely 

 differing in length; 2nd pair with the antepenultimate joint nearly twice the 

 length of the last 2 combined; 3rd and 4th pairs of moderate size and scarcely 

 spinulous. Uropoda with the outer ramus about half the length of the stem, 

 inner ramus somewhat shorter, and armed inside with about 8 spinules (4 on 

 the 1st, 2 on each of the last 2 joints), apical spine, as usual, strong, mucro- 

 nate, not defined at the base. Telson extending as far as the stem of the uropod;i, 

 proximal thickened part occupying about 1 / s of the length, distal part rather 

 narrow, and armed on each side with about 8 spinules, apical spinules of about 

 the same appearance as the lateral. Colour reddish brown. Length 10 mm. 



Adult male much more slender than the female, with the anterior division 

 of the body less strongly arcuate above. Carapace, as usual, less deep and more 

 tumid in its anterior part, exhibiting, however, the very same sculpture as in 

 the female; pseudorostral projection shorter and more obtuse. Last pedigerous 

 segment with the lateral corners very little produced, though clothed with the 

 usual plumose seta3. Tail unarmed. Inferior antennse remarkably short, scarcely 

 exceeding in length the anterior division of the body; the other appendages 

 transformed in the usual manner. Length 11 mm. 



Remarks. According to Dr. Stuxberg, the species generally known as 

 Diastylis CCuma) Edwardsii Kr0yer is without any doubt identical with the form 

 recorded by Lepechin as early as in the year 1778 as Oniscus scorpioides, and 

 the specific name proposed by that author ought accordingly to be retained for 

 this species. The Cum a brevirostris of Kroyer is unquestionably the adult male 

 of this species. It is an easily recognizable form, being at once distinguished 

 from the other northern species by the peculiar sculpture of the carapace, which 

 is equally distinct in both sexes. The shortness of the inferior antennaa in the adult 

 male is a unique character as regards the species of the present genus. 



Occurrence. I have found this form rather abundantly in several places 

 on the Finmark coast, as also off the Lofoten Islands. During the Norwegian 

 North Atlantic Expedition it was also taken in the inner part of the Saltenfjord; 

 but it has not yet been observed outside the polar circle. 



