INOCERAMUS. 



301 



Nou 1882. Inoceramus cardissoides, H. Schroder. ZeitscLr. d. deutsch. geol. 



Gesellsch., vol. xxxiv, p. 271, 

 pi. xvi, fig. 1. 



Description.— Shell very inequilateral, oblique, moderately convex, with the 

 anterior marginal part sloping rapidly. Height considerably greater than length. 



Fig. 57. 



Fig. 58. 



\ 



$,j 



IV 



7 



%i. 



ma 



Fig. 57. — Inoceramus cardissoides, Goldf. Upper Chalk (probably zone of Actinocamax quadratus), near 



Speeton. Sedgwick Museum. Left valve. Posterior wing missing. Natural size. 

 Fig. 58. — Inoceramus cardissoides, Goldf. Upper Chalk, probably Kent. British Museum, No. 98209. 



Part of left valve. Natural size. 



Ventral margin convex; anterior margin slightly curved. A broad concave 

 depression extends from behind the umbo to the postero-ventral extremity, and is 

 limited posteriorly by a straight, sharp ridge, behind which is a wing-like part of 

 the shell. 



Ornamentation consists of strong, widely separated concentric ribs, with a steep 

 ventral slope and a more gentle dorsal slope; in the interspaces are small con- 

 centric ribs, which are crossed by small radial ribs giving a more or less distinctly 



40 



