690 MR. F. CHAPMAN ON THE BARGATE BEDS OP SURREY. [Nov. 1 894, 



8. Cttheridea bicarinata, Jones & Sherborn. 



Proc. Bath N. H. & Antiq. F.-Club, vol. vi. (1888) no. 3, 

 p. 270, pi. iv. fig. 5 a-c. 



In this series there is only one specimen which can with some 

 certainty be referred to the above species ; this specimen, however, 

 is destitute of the tuberculations of the exterior of the hinge-line 

 such as are present on the specimens described from the Fuller's- 

 Earth clay of Midford, but probably not of specific value. 



One valve from clay of Bargate Pebble-beds, Littleton. 



9. Cttheridea bicarinata, Jones & Sherborn, var. nodulosa, nov. 



(PI. XXXIII. fig. 2 a, b, c.) 



This variety differs from the specific form, C. bicarinata, in 

 having the two ventral carina? terminating posteriorly in a nodulous 

 prominence; and it also has a median longitudinal, with a feebler 

 dorsal ridge ; these two ridges also end in a similar lumpy process in 

 the postero-dorsal region. 



Six valves from clay-seams in Bargate Pebble-beds, Littleton. 



10. Cttheridea vellicata, sp. nov. (PI. XXXIII. fig. 3 a, b, c.) 



Valve subovate, broad in front, tapering and blunt behind, with 

 a flanged posterior margin. Dorsal edge straight ; ventral margin 

 curved and steep, surmounted by a sharp keel running close to the 

 edge. The central area is occupied by a low ridge, and near the 

 postero-dorsal margin the surface is pinched up into a short keel 

 raised posteriorly into a blunt process. Length of valve J^ to t^j in. 

 (U-42 to 0-5 mm.). 



Two valves from clay-seams in Bargate Pebble-beds, Littleton. 



11. Cttheridea fenestrata, sp. nov. (PI. XXXIII. fig. 4.) 



Valve subovate, with a steep ventral margin sloping away to- 

 wards the front and back as in the above species C. vellicata, to 

 which, as to ridges and shape, it bears much affinity. The surface 

 is decorated on the dorsal side of the ventro-marginal ridge with 

 angular or square-shaped pittings arranged in two series. This 

 fenestrated surface of the test reminds one of Cyiheropteron fenes- 

 tratum, Brady 1 ; that species, however, has the fenestration con- 

 fined to one series of markings, besides being separated by generic 

 differences. Length of valve -^ in. (0'5 mm.). 



One valve from clay of Bargate Pebble-beds, Littleton. 



12. CrTHERiDEA CRATiciJLA, Jones & Sherborn. 



Proc. Bath N. H. & Antiq. F.-Club, vol. vi. (1888) no. 3, p. 272, 

 pi. iv. figs. 9 a-c and 10 a-c. 



The specimens originally described by the above authors were 

 from the Fuller' s-Earth clay of Midford. 



One valve from clay of Bargate Pebble-beds, Littleton. 



1 'Challenger' Report, Zoo!., vol. i. (1880), G. S. Brady, Ostracoda, p. 139 

 pi. xxxiv. fig. t5, a-d. 



