268 



wrinkles or undulations; not pitted; with a few limited 

 flattened areas in the anterior and posterior regions. Hingement, 

 as in pi. i., fig. 2. 



One specimen ; Yellow Fullers-earth Clay, Midford. 



45. CYTHERIDEA VISCERALIS,* Sp. n. 



PL iii., figs. 6 a, h, c. 



Oblong with oblique ends, subrhomboidal ; truncate in front, 

 angular behind. Surface punctate, swollen into irregular lumps, 

 and having a short depression in the antero-ventral region, and 

 a flattened area along the postero-ventral border. 



One specimen; Blue Fullers-earth Clay, Midford. In Mr. 

 Walford's collection, there is a specimen from the base of the 

 Fullers-earth Oolite between Notgrove and Bourton, which we 

 regard as an immature specimen of this form. It difl'ers from the 

 figured individual in being smaller, and in having the postero- 

 ventral swelling more prominent ; thus giving the valves a more 

 triangularly sagittate edge view. 



46. CYTHERIDEA STRIBLITA,t sp. U. 



PI. iii., figs. 7 a, b, c. 



Sub-oblong, with rounded anterior margin, and angular 

 posterior margin ; sloping on the postero-dorsal margin, and 

 flattened at its extremity. Surface smooth, with a few pits; 

 irregularly swollen, and partially crossed by a sulcus, it looks 

 like a dough cake. The hingement is as in pi. i., fig. 2. 



Two specimens ; Blue Fullers-earth Clay, Midford 



47. CYTHERIDEA IGNOBILIS, sp. n. 



PI. iii., figs. 9 a, h, e. 

 Neatly sub-oblong, convex ; rounded in front, straight at 



* Like bowels. t A twisted cake. 



