REPORT ON THE OSTRACODA. 155 



Cypridina, Milne-Edwards. 



Cypridina, Milne Edwards (1838), Baird (1840), Dana (1855), Claus (1865), Brady (1866-71), 



Sars(1865). 

 Gijprella, Bosqnet, 1847. 

 Daphnia, M'Coy, 1844. 



Shell smooth, thin, and nsually flexible ; notch shallow, shell above the notch curved, 

 and more or less sharply uncinate, rounded ofi" below ; j)Qsterior extremity rounded, or 

 slightly exserted. Anterior antennae seven-jointed, and bearing a few setse of moderate 

 length, the fifth joint, however, having one long apical seta ; natatory branch of posterior 

 antenna nine-jointed, each joint bearing a single long ciliated seta, except the first, which has 

 none, and the last which has four; secondary branch slender, two or three-jointed. Basal 

 joint of the mandibular foot (the mandible proper), bearing a subconical and densely 

 hairy process ; penultimate joint much elongated, and beset on the inner margin with 

 numerous ringed setae, last joint very short and almost obsolete. Outer lobe of the first 

 pair of jaws provided with a narrow membranous appendage ; second pair having two 

 strongly ungulate segments. Eyes widely separated and situated against the central 

 portion of each valve, deeply coloured, and much larger in the male than the female. 

 The oviparous foot is divided into unec[ual uncinate processes at the apex, and on its distal 

 half bears numerous long divaricating lateral setae, which are dentatecl towards the apex, 

 the teeth being opposite, and directed forwards, thus giving the appearance of a number 

 of inverted arrow-heads. The distinctive character of the restricted genus Cypridina 

 (as defined by G. 0. Sars, whose description is followed with some little modification in 

 the foregoing diagnosis) is the conical process attached to the base of the mandibular 

 foot. It is perhaps doubtful whether the type species, described by Milne-Edwards, 

 really belongs to the genus as thus restricted. Sars, however, excepts Cypi'idina luteola, 

 Dana, Cypridina messinensis, Claus, and Cypridina norvegica, Baird, as members of the 

 genus, and has himself described another species, Cypridina megalops} Probably also 

 Cypridina japonica,^ Brady, may be taken for a true Cypridina. 



1. Cypriditiaformosa (?), Dana (PL XLII. figs. 9-11). 



Cypridina formosa, Dana, Crustacea of the United States' Exjjloring Expedition, p. 1296, 

 pi. xci. fig. 5. 



Shell thin and flexible, reticulated in structure, dark brown in colour ; seen from the 

 side, broadly oval, height ecpal to about thi-ee-fourths of the length, notch of moderate 

 depth, and situated near the middle of the anterior margin ; posterior extremity broadly 

 rounded, and produced in the middle into a broad obtusely rounded prominence ; dorsal 

 and ventral margins boldly arched, ventral the more convex of the two ; seen from above 



1 Undersdgelser over Hardangerfjordlen's Fauna, 1871. - Trans. Zool. Soc, vol. v., 1865. 



