OF CONCHOLOGY. 201 



I replaced bj Sat/ana, in consequence of Brongniart having 

 named a shell 0. ? convexa, in " Des. Geolog. des Env. de Paris, 

 par Cuv. et Brong." The figure of this shell reminds us of the 

 genus Oyrena, especially as the specimens were associated with 

 fresh water shells. It is certainly not a Caryatis, to which genus 

 C. convexa. Say, belongs. No figure or description of the hinge 

 of Brongniart's species is given. 



The recent shell known by the name of 0. convexa is distinct 

 from the fossil shell of that name and was described by me under 

 the name of (7. Sayana, Sillm. Journ. vol. xxiii. It is easily 

 distinguished from the former, as it is larger, more elevated and 

 obtuse posteriorly. The fossil species, therefore, will stand as 

 Caryatis convexa, and the recent as Caryatis Sayana. This 

 genus of Roemer is a distinct and very natural group among the 

 Veneridae. 



C. ExmuA, Conrad. PI. 11, fig. 3. 



Subcordate, short and elevated, ventricose, thin in substance ; 

 summits prominent; posterior side truncated; lunule cordate, 

 indistinctly defined. 



Locality. Claiborne, Alabama. Rare. Eocene. 



