REPORT ON THE OSTRACODA. 163 



Conchcecia and Halocijpris, I am unable to find any difi'erences sufficient, in my opinion, 

 to form grounds of generic distinction. These descriptions, owing, doubtless, to paucity 

 of material at the command of the author, are scarcely detailed enough to serve as stand- 

 ards of comparison now that our knowledge of allied forms has been so greatly ex- 

 tended. On the other hand, the very minute and careful description of the genus 

 Conchcecia, given by G. 0. Sars as the result of the dissection of numerous specimens, 

 leaves nothing to be wished for so far as that genus is concerned. Nor can I find any 

 material difference between the anatomy of Conchcecia as described by Sars and that of 

 Halocijpris, as shown by my own drawings in the plates of this monograph. It can 

 scarcely be doubted that the species taken during the cruise of the Challenger belong to 

 Dana's genus Halocypris ; but whether Sars is correct in referring his Norwegian speci- 

 mens to Conchcecia rather than to Halocypris, is, I think, questionable. In the struc- 

 ture of the mandible, where, according to Dana, one of the most important differences 

 lies, Sars' specimens seem to me to be more in agreement with the latter genus. But 

 if, on the contrary, the Norwegian specimens be rightly assigned to Conchcecia, then, as 

 I can see no reason why they may not with equal propriety come under Halocyp>ris, it 

 follows that one of the two generic names must lapse. Adopting this view, and seeing 

 that Halocypris is already perhaps the better known name, I have here used it to desig- 

 nate the genus. 



Halocyp)ris, Dana (1853). 

 Halocypris, Conchcecia, Dana ; Halocupris, Glaus, Lubbock ; Cunchmcia, G. O. Sars. 

 Valves usually elongated, and produced in front into a distinct beak-like process, with 

 an underlying notch ; surface of the shell more or less delicately striated in a concentric 

 or reticulated manner. Anterior antenuEe in the female small, indistinctly jointed, and 

 bearing at the apex four or five setae, of which three or four are small, and one very long ; 

 in the male the antennae is much larger, four-jointed, and mobile, bearing four apical 

 setae, one of which is very small, the other three very long, equal, transversely ringed, and 

 densely cihated, one of the three bearing a series of marginal appendages. Posterior 

 antennae very large and stout, the basal portion elongated, triangular, and about half as 

 long as the shell of the animal ; natatory branch seven or eight-jointed, the first joint 

 occupying about two-thirds of the entire length of the branch ; secondary branch 

 biarticulate, the first joint greatly dilated,' second very smaU, bearing in the female a few 

 long subequal setae, in the male a strongly .falcate claw, from the base of which spring a 

 few not very long unequal setae. Mandibles armed at the free extremity with a single 

 strong tooth, and along the crescentic margin with one or more series of much smaller 

 teeth ; palp very stout, four-jointed, the basal joint excessively stout, produced down- 

 wards as far as the extremity of the mandible, and divided at the apex into a series of 

 several small teeth. First pair of maxillae composed of two incisive lobes, which are 



