31 t 



hitherto only seen female specimens of this form. The male may undoubtedly be 

 assumed to exhibit some difference from those of the 2 preceding species, at least 

 in the structure of the last pair of legs. 



Occurrence. Some specimens of this form were found in the same 

 plankton-proofs in which .C. obtusifrons occurred (Stats. 8 & 9 of the cruise of 

 the "Michael Sam"), and moreover at Stat. 34, located considerably farther north, 

 at some distance east of Jan Mayen, the depth at the last-named Station being 

 recorded to be from 500 to 1000 metres. Judging from the above-mentioned 

 occurrences, I think that the present species ought to be referred to the fauna of 

 Norway, an opinion which has been still further confirmed by recent investigations 

 of Mr. Nordgaard, who has found a solitary specimen in a plankton-proof taken 

 in the year 1899 in the Ofoten Fjord. 



Distribution. Not unfrequent at 6 different Stations in the Polar basin 

 explored by Nansen. At one of the Stations it occurred at the very surface of 

 the sea, at the others at some depth below the ice. 



Gen. 8. UndlnOpSiS, G. 0. Sars, 1884. 



Syn: Bradyidius, Giesbrecht, Scott. 



Generic Characters. Body in female comparatively robust, in male somewhat 

 more slender. Cephalosome, as in the other forms of this family, coalesced with 

 the 1st segment of metasome, front terminating below in a distinctly bifurcate 

 rostrum. Last segment of metasome produced on each side to a strong, posteriorly- 

 pointing projection. Urosome in female comparatively short, in male more slender, 

 with shortened anal segment. Caudal rami likewise short and of a structure 

 similar to that in Chiridius. $ye distinct, longitudinal. Anterior antennae in 

 female not very slender, 24-articulate, with the last articulation well defined, 

 bristles of the anterior edge unusually strong, partly annulated, and curved in 

 different directions, those at the tip more or less distinctly ciliated ; same antennae 

 in male comparatively more slender, with band-like sensory appendages on the 

 proximal part. Posterior antennae with the rami not very unequal in length. 

 Oral parts on the whole resembling 'those in Chiridius; posterior maxillipeds, 

 however, considerably more robust. Natatory legs very strongly built, inner ramus 

 of 1st pair uniarticulate, of 2nd pair biarticulate, of the 2 succeeding pairs 3- 

 articulate. Last pair of legs in male slender, more or less asymmetrical. 



. This genus was proposed many years ago by the present author, 



