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



III. — Description of the Entomostraca of the Pleistocene Beds 

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

 Jones, Esq. 



[With a Plate.] f''"^^ ""^'''^ 



1)/T« .ft98«iUH 



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 progress 

 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 filling 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 plumei 

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



1. Cypris setigera, nobis. Length Jy inch. PI. III. fig. 3 a, 6, c. 



Carapace ovate, somewhat pear-shaped. Valves conYtx ; elHp- 

 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 difi'ers from it in 

 being smaller and less gibbous, and in having sj)ines, anterior 

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



Plentiful in the peat-beds of Newbury, Berks. .,> _n 



2. Cypris Browniana, nobis. Length ^^^ inch. PI. III. fig. 1 a, 



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, subreniform. 



Dorsal aspect elongate-oval ; anterior obtusely ovate. 



