90 G. O. Sars. 



lines, lower edges finely ciliated in the middle, infero-posteal 

 corners without any traces of the usual serrations. Ocellus 

 rather large, though a little smaller than the eye, both widely 

 remote from the dorsal edge of the head. Antennulæ not 

 extending to the tip of the rostrum. Lip-plate rather large, 

 with the lower edge evenly curved. Caudal part of the usual 

 slender form, gradually tapering distally, supra-anal projec- 

 tion obtusangular, lower corner wanting, marginal denticles 

 well defined, numbering about 20 in each row, the outermost 

 somewhat larger than the others and somewhat remote from 

 the tip, caudal claws very slender, with a row of delicate 

 spinules extending from the basal denticle to about the middle. 

 Male exhibiting the usual secondary sexual characters, and 

 not very different in external appearance from the female. 

 Body in both sexes highly pellucid, with a faint yellowish 

 tinge, dorsal part of carapace in ephippial females, however, 

 considerably darkened. Length of adult female 0,83 mm., of 

 male 0,60 mm. 



Remarks. — In the peculiar and, as it were, blunted 

 shape of the rostrum, this form exactly agrees with the 

 European form described by Kurz as C. latirostris, and in- 

 deed, I at first believed the two to be identical. On a closer 

 examination, however, it is found to differ very markedly 

 in at least one character, viz., the entire absence of the 

 serrations constantly present in the European species at the 

 infero-posteal corners of the valves. I have examined numer- 

 ous specimens of the present form, but in none of them 

 could I detect even the slightest trace of such serrations. 

 As stated above, the 2nd South American species, C. aloni- 

 ceps Ekman, is quite destitute of these serrations; but these 

 2 species cannot be confounded with each other, as the shape 

 of the head is very different. 



