45 



author as Cuma aiigtduta, is, according to my opinion, in which I am supported by 

 Dr. Hansen, the adult male of this species. It is one of our largest and tinest 

 species, and in the polar sea it attains a still larger size. I have examined 

 some specimens kindly sent to me by Dr. Stuxberg from the Siberian polar sea, and 

 which had a length of no less than 26 mm. It is, moreover, easily recogni/rd 

 from our other species by its comparatively slender form and by the large spini- 

 form processes formed by the lateral parts of the last pedigerous segment. The 

 species which most closely resembles it is D. Bradiji Norman (not yet found off 

 the Norwegian coast), and indeed some forms of D. Rathkei exhibit by their more 

 spiny carapace, as it were, a transition to this species. 



Occurrence. I have met with this form along the whole coast of Norway, 

 from the Christiania Fjord to Vadso, and in some places in great abundance. 

 It is generally found in moderate depths varying from 10 to 30 fathoms, especi- 

 ally where the bottom consists of very loose mud, in which it buries itself with 

 great dexterity. Sometimes I have found it rather abundantly on a bottom covered 

 with a thick layer of putrid dark mire avoided by most other Crustacea. Although 

 young males are nearly as frequent as females, I have not yet met with any 

 sexually mature male specimen (= ; Cuma angulata Kr.), probably owing to the 

 circumstance that the existence of such specimens is limited to certain short 

 periods of the year. 



Distribution. Kattegat (Meinert), Bay of Kiel (Moebius), Pommerian 

 coast (Zaddach), the Baltic (Lindstr0m), Heligoland (Ehrenbaum), Dutch coast 

 (Hoek), British Isles (Sp. Bate), Atlantic coast of North America (Verrill), Green- 

 land (Hansen), Spitsbergen (Norw. North Atl. Exp.), Franz Joseph Land (Heller), 

 the Barents Sea (Hoek), the Kara Sea (Hansen), the Siberian Polar Sea (Stuxberg). 



2. Diastylis cornuta (Boeck). 



(PI. XXXV & XXXVI). 

 Cuma cornuta, Boeck, Christiania Vid. Selsk. Fork. 1863, p. 190. 



Syn: Diastylis bispinosa, G. O. Sars (not Stimpson). 

 bicornis, Sp. Bate. 



Specific Characters. Female: Body less slender than in the preceding 

 species, with the anterior division rather tumid and oval in form. Carapace 

 comparatively large, about twice as long as the exposed part of the trunk, and 

 somewhat vaulted above, surface rather uneven, owing to numerous unequal spiniform 

 projections, some of which are very conspicuous, 2 of them especially, issuing one 

 on each side of the frontal lobe, being distinguished by their size, looking like a 



