29 



abundance in almost all our deep fjords, from the Christiania Fjord up to the 

 Vestfjord, but only in greater depths than 100 fathoms. It is accordingly, at any 

 rate off the coast of Norway, a pronounced deep-water form, though it is very 

 probable that in more northern latitudes it may ascend nearer to the surface. 



Distribution. Though 1 am much inclined to believe that this form is 

 of arctic origin, the statements about its occurrence in the Arctic Ocean cannot be 

 regarded as fully reliable, as it may very easily be confounded with the succeeding 

 species. In the Polar basin investigated by Nansen, the present species did 

 not occur. 



10. Chiridius obtusifrons, n. sp. 



(PI. XVII.) 



Chiridius armatus. G. O. Sars. The Norw. North Polar Expedition. Crustacea, p. 64, PI. XVII 



(not Boeck.) 



Specific Characters. Female. Very like the preceding species, though 

 perhaps a little more slender of form. Front without any trace of a rostrum. 

 Lateral corners of last segment of metasome, as in C. armatus, drawn out to 

 comparatively short and slightly divergent acute projections. Urosome rather 

 slender, attaining almost half the length of the anterior division; caudal rami 

 somewhat more produced, exceeding in length the anal segment, and but slightly 

 diverging. Anterior antennae scarcely longer than the anterior division of the 

 body. Posterior antennae with the inner ramus rather short and stout, outer one 

 fully twice its length. First pair of legs about as in C. armatus. Inner ramus 

 of 2nd pair uniarticulate, of 3rd and 4th pairs imperfectly 3-articulate, the 2 

 basal joints being partly confluent. Male much smaller than the female, but 

 otherwise resembling that of C. armatus. Last pair of legs, however, much more 

 slender, and without any trace of an inner appendage to the 2nd joint. Length 

 of adult female 4.20 mm., of male 2.90 mm. 



Remarks. As stated above, this form was at first regarded by the present 

 author as identical with Boeck's species, to which it certainly bears a perplexing 

 resemblance. On a closer comparison, I have however found that in reality it 

 differs in some points so very markedly, that it ought more properly to be re- 

 garded as a distinct species, for which the specific name obtusifrons is here proposed, 

 derived from the fact of the total absence of any rostral projection on the front. 

 Moreover, the urosome appears considerably more elongated in the female, and 

 the caudal rami are likewise somewhat more produced. On the other hand, the 

 anterior antenna} are comparatively shorter, and in the 2nd pair of legs the inner 

 ramus is uniarticulate, as in the 1st pair, without any trace of a subdivision. 



5 Crustacea. 



