138 



CJtETxiCl<:uL8 LAMELLlliKAAClllA. 



Descrqilion. — yiiell large, oval, convex, moderately inequilateral, anterior pari 

 produced. Antero-dorsal margin concave. Anterior margin rounded, ])assing 

 gradually into the convex ventral margin wliicli curves upward to join the 

 posterior margin. Posterior margin i-ounded, sometimes forming a large and 

 rounded angle with the ventral margin, but sometimes passing into it gradually. 

 Postero-dorsal margin convex. Postero-dorsal part of valves compressed, some- 

 times limited by an indistinct carina. Umbones prominent, curving forward and 

 inward. Lunule indistinctly limited. Escutcheon narrow, deep, with a sharp 

 edge. Ornamentation consists of growth-lines. 



Fm. 20. — Cijprina (Vcnilicardia) proUnsa, sp. nov. Lowi-r (JivcnsanJ (i'c)«u-)jud), AtliorCukl. 

 Socls""ick Museum. Kiirlit valvt'. x -J. 



Measurements 

 (1) 

 lOG 



84 



Leni>th 



o 



Height 



(2) (3) (4) 



105 . 103 . 99 



89 . 91 . 88 



(1—6) Perna-hcd. Atlu'ilifkl. 

 (0) Crackers, Atliorfiekl. 



AJfinUics. — The characters which distinguisli this species fVom (_'. (uujuhdii, 

 Sowerby, are : the umbones are less anterior and the shell is less inequilateral ; 

 the umbonal part of the shell is relatively smaller; the carina is less distinct; the 

 anterior part of the shell is more produced ; the posterior part is more I'oundcd ; 

 the ventral margin has a greater cui'vature; the shell is less inflated, so that the 

 marginal parts of the valves meet at a smaller angle. The anterior i)art of the 

 shell resembles that of C. tnuicafa, but tlie posterior part is more rounded, and 



