68 CONTRIBUTIONS 



C. minima. Plate 2. Fig. 45. 



Description. Shell subrotund, angular above, subequi- 

 lateral, concentrically and very minutely striate ; lunule 

 large, elliptical ; beaks somewhat elevated, pointed, com- 

 pressed ; cavity of the shell deep and rounded, margin 

 entire. 



Diam. .... Length .1, Breadth .1, of an inch. 



Observations. A single valve only of this little Cytherea 

 has been observed by me. It may possibly be the young 

 of the trigoniata. This specimen is, however, more equila- 

 teral and the striae are more minute. 



Of this genus three species have been observed in Great 

 Britain, one of which is from the London Clay. In M. 

 Deshayes's Tertiary Tables we find fifty-nine species. 

 Twenty-two of these are from the Paris basin, and eigh- 

 teen from Dax (Miscene period). Mr Say has described 

 two species from the Tertiary of Maryland, and Mr Conrad 

 one from the same state. 



GENUS VENERICARDIA. Lamarck. 



V. transversa. Plate 2. Fig. 46. 



Description. Shell very transverse, elliptical, inflated, 

 very inequilateral ; obliquely ribbed ; substance of the 



