RECENT BRITISH OSTRACODA. 



395 



pecies, C. albomaculata, convexa, rubida, and pulchella, present intermediate 



and could not be included under either of the gener 



denned by Sars. The chief 



distinctive characters taken by him as the ground of separation are the length of the 

 urticatus seta of the lower antenna (which, in the females of " Cythereis" is exceeding] y 



short), the structure of the mandibular palp, and the abdominal 

 may be tabulated as follows : 



These 



Urticating seta of lower antenna 



Mandibular palp 



Cy there, Sars. 



of equal length in male and 

 female. 



composed of three joints, and 

 simply setose; two branchial 

 filaments. 



Cythereis, Sars. 

 ery short in the female. 



rami 



forming two obtuse lobes. 



composed of four joints, and 

 bearing three strong, curved 

 pectinate setae; five branchial 

 filaments. 



bearing two or more stout ciliated 

 setae. 



If the characters here ascribed to Cythereis could have been shown to be uniformly 



coincident 



ith the quadrangular and rugose forms of carapace for which the genua 



Cythereis was 



lly proposed, or even if they could have been applied with \ 



.- any group, without respect to shell-structure, they might perhaps, though dubiously, 

 have been allowed to form the basis of a distinct genus ; but seeing that we have form 



there seems no reasonable 



distinctly partaking of the characters of both generc 

 but that of uniting the two under one name. 

 C. albomaculata. with the shell-characters and urticating setae of Cyth 



has the 



mandibular palp and abdominal rami of Cytl 

 form of carapace, but much moi 



C. con rem is perhaps intermedial 



near to Cyth 



than to Cyth 



while the 



Both specios possess 



urticating seta and mandibular palp agree with those of Cyth 

 further characters (in the lower antenna,) which are, so far as I know, pem*« ^ them- 

 selves. The abnormal characters of C. rubida and pulchella will be panted out m 

 descriptions of those species. 



, Valves elongate or reform, punctate, not prominently rugose or spinas 

 * Mannar palp threejointet, simply setose; urticating seta long, eoual « the male^l- 



,«/«♦ ^TVTTI fi-s 47-56, and Plate XXXIX. fig. 2.) 



I. Cythere lute a, Muller. (Plate XXVIU. n a s. a/ • 



.-.._!....«_ ft A. Sars, Oversigt af Gorges mar. ustra. 

 Cythere lutea. Muller 



ere lutea, Muller, .untomosiraca, p. w, _~. ~ 



p. 28 , Zenker, Anat.-syst. Stud, iiber die Krebsthiere p. 88, 1* • 

 reniformis, Baird, Brit. Entom. p. 169, tab. xx. figs. , a f- 



Scandinavian type. Distribution : Recent 



Med 



I — Raised 



Carapace reniform, compressed 



^aiapace reniiorm, coiupicoocw. ~— - - i 



^d nearly equal ; the greatest height in the middle, equ a 



Baffin's Bay, North Sea, Baltie, Great BriUin, Ireland, 



In tU female the extremities are obliquely rounded 

 In tnejet % considerably more than 



half the length 



; the greatest ^^T^ arched , ventral deeply 

 Dorsal inar-m gently and evemv 



borders the extremities 



the 



i tengtn. juorsai margin 5 ^ v - - ^^ wMch borders tnc atnuui^ 



partial disappearance of a broad natte o ^.^ fa comprcsse d, oblong 



»st of the inferior margin. Seen from aDov , g ^ % 



