Mr. T. R. Jones on some fossil Eutomostraca. 25 



III. — Desaiption of the Entomostraca of the Pleistocene Beds 

 of Newbury, Copford, Clacton, and Grays. By T. Rupert 

 Jones, Esq. 



[With a Plate.] 



The history of the recent British Entomostraca has lately been 

 completed by Dr. Baird, and the Entomostraca of the " Carbo- 

 niferous," " Permian," and " Cretaceous " formations of Britain 

 have been described by Mr. M'Coy and myself : some progi-ess 

 has thereby been made towards the completion of a general 

 history of the British Entomostraca, recent and fossil. Still 

 however a great proportion of the fossil species remain unde- 

 scribed, and the following account of the pleistocene Entomo- 

 straca is intended as a contribution towards the filhng up of this 

 deficiency. 



Family Cypridid^, Baird (Brit. Entom. p. 14). 



Entomostracous crustaceans, minute, aquatic ; animal inclosed 

 in a bivalved carapace. 



1. Genus Cypris, Miiller. 



Gen. Char. Animal swimming, provided with two pairs of plumed 

 antennae, and two pairs of feet. Inhabiting fresh-water. 



1. Cypris setigera, nobis. Length Jy inch. PI. III. fig. 3 a, b, c. 



Carapace ovate, somewhat pear-shaped. Valves convex ; ellip- 

 tical on the dorsal and nearly straight on the ventral border ; 

 narrower and slightly flatter anteriorly ; covered with fine spines ; 

 bordered anteriorly and posteriorly by narrow, rounded, marginal 

 ridges. Right valve narrower, straighter on the dorsal, and more 

 incurved on the ventral margin than the left valve. 



Dorsal aspect acute- oval ; anterior oval. 



This species approaches Cypris aurantia, Jurine (Baird, Brit. 

 Entom. p. 159. n. 15. tab. 19. fig. 13) ; but it differs from it in 

 being smaller and less gibbous, and in having spines, anterior 

 marginal ridge, and a perfectly different pattern of lucid spots. 



Plentiful in the peat-beds of Newbury, Berks. 



2. Cypris Browniana, nobis. Length -^-^ inch. PI. III. fig. I ar, 



b, c, d. 



Carapace short and broad, somewhat square. Valves convex, 

 depressed anteriorly, smooth. Left valve subquadrangular, ob- 

 liquely rounded anteriorly, semicircular posteriorly; slightly 

 arched on the dorsal and ventral borders. Right valve smaller 

 than the left, subreniforra. 



Dorsal aspect elongate-oval ; anteiior obtusely ovate. 



