RECENT BRITISH OSTRACODA. 



171 







teeth ; palp Particulate, first joint stout, bearing externally a short, bisetose branchial 

 appendage, last narrow, beset with long plumose seta?. Incisive portion of the first pair 

 of jaws small, forming a simple setiferous lobe ; palp very large, four-jointed, two-branched, 

 second joint bearing externally a long, narrow, and obsoletely biartieulate branch, which 

 is terminated by long setae. Second pair of jaws membranaceous, three-jointed; penul- 

 timate joint bearing externally a small branch which terminates in a single seta ; furnished 

 at the base with a large branchial plate. Postabdominal plates short, p< 

 shortly digitate and armed between the segments with acuminate claws. 



Animal 



jj 



ddl 



ming actively like the Lynceidse 



Sars thinks that there are probably several species of this genus, but he lias not been 

 able accurately to examine and determine more than one. The two species here described 

 I myself know only from their external characters, the few British specimens hitherto 

 found being apparently empty shells. 



1. Polycope orbicularis, G. O. Sars. (Plate XXXV. figs. 53-57.) 



Polycope orbicularis, G. O. Sars, loc. cit. p. 122. 



Shell of the female, as seen from the side, subcireular, greatest height 

 slightly less than the length ; anterior margin slightly narrowed and produced, portHtlOt 

 evenly rounded, superiorand inferior margins holdly arched. Outline, as seen from above, 

 ovate, tapering equally to each extremity ; greatest width in the middle, equal to mo* 

 than half the length. Valves finely punctate and divided by fine ret.cukmd nbs into 

 numerous polygonal areohe. Colour pale yellow, marked with patches rad.atn , 

 .tripes," Sars) of a darker red colour. « Basal joint of the upper antenna, ongerttan 

 the two others combined, densely hairy on the anterior »^"£££ 

 short seta, last joint ending in five long slender set, ; « IjjMJjkj -J- 

 eight-jointed, the last seven joints short and subequal ; the other tnee , I 



longer than x,he two following combined, bearing eight long partt^ ££££ J£ 

 dibles divided at the apex into five teeth, the most -j"^^ ^ 



nail. B Wo, +w «i« mandible itself, its last joint equal in icn w i 



palp shorter than the mandible 

 and bearing seven ciliated setae 



Secondary branch of the anterior 



and bearing seven ciliated seta?, seconucu j -" aiid ^ cm]r] 



little beyond the apex of the palp, and terminating in about «g ^ ^ c0|atod 

 setae. Branchial plate of the posterior maxil a3 narroj , > 1 ^^ ^ dcorcaginjr 

 marginal setse. Postabdominal plates armed witn six ^ rf ^ 



gradually in length backwards ; behind them two short set^ * 

 abdomen bearing three brushes of short hairs. Male unknot 



Length ^ in. 



Hab. Shetland and the Minch {Rev 



M. Norman 



shell-sand, Roundstone (Dr. Alcock). scu lpturing of different specimen 



There seems to be much difference in the amount o 1 - • h ^^ 



mere seems to oe mucn uiueicu^ — — perfectly smooth, tnougu iuum >j 



of P. orbicularis. In adults the shell is often f" 1 ^ from she n. san d at Jloundston. 

 bearing an obscure reticulated pattern; a singe othcr s]K > c i ni(m 



distinctly sculptured than any othcr „. 



(represented at figs. 56 & 57; is moi* — — - » - ticuli , tL , d 

 that I have seen. Young specimens are punctate but not 



