266 



features. In outline C BlaTceana has some alliance with the recent 

 Cythere impluta, Brady (Challenger Eeport, 1880, p. 76, pi. xvi., 

 fig. 3), but this latter has a fuller ventral margin, and a more 

 sharply marked outline. 



Two examples ; Blue Fullers-earth Clay, Midford. 



40. CYTHERIDEA RENOIDES, sp. n. 



PI. iii., figs. 1 a, b, c. 



Subreniform, smooth, but pitted with large, shallow, scattered 

 holes. Ventral margin slightly incurved ; dorsal margin convex, 

 but with a distinct hinge-line. Ends rounded, the posterior 

 narrowest. Edge view, bluntly lanceolate ; end view, broad- 

 ovate. Hingement, like that of pi. i., fig. 2. 



G. S. Brady's figure of Ci/theridea papillosa, Bosquet (Trans. 

 Zool. Soc, vol. v., 1866, pi. Iviii., fig. 8), is almost identical la 

 outline with our figure, but it is broader (higher) than Bosquet's 

 species ; and neither of the two agrees with ours in the surface 

 ornaments and end view. 



Four examples from the Blue, and one from the Yellow Fullers- 

 earth Clay, Midford. 



41. CYTHERIDEA PULVINAR,* Sp. 71. 



PI. iii., figs. 2 a, h, c. 



A large and sub-oblong form, both ends broadly rimmed ; 

 semicircular in front, angular behind, and having both the 

 ventral and the dorsal margin sinuous and swollen. Surface 

 smooth ; transversely undulate to a slight degree, and marked 

 with large shallow scattered pits. Edge view, lanceolate, with 

 pinched ends ; end view, ovate, with blunt ends. Hingement, 

 as in pi. i., fig. 2. 



Three specimens , Blue Fullers-earth Clay, Midford. 



* A pillow. 



