PLATE XXXVI. 



PAGIC 



Figs. 1-3. Protocakdia lenis Conrad 172 



1. Exterior of riglit valve. 1 mile southeast of Mason Springs, 

 la. Interior of same valve. 



2. Interior of left valve. Pamunkey Eiver, Va. Acad. Nat. Sci. Phila. 

 2a. Exterior of same valve. 



3. Exterior of right valve from same locality and in same collection. 



Fig. 4. DiPLODONTA MAKLBOROENSIS n. sp 173 



Exterior of left valve. Upper Marlboro. X 7/4 



Figs. 5, 5a, 6, 7. Diplodojs^ta hopkinsensis Clark J 74 



5. Exterior of left valve. Evergreen, Va. 

 5a. Interior of same valve. 



6. Exterior of right valve. Same locality. 



7. Hinge much enlarged. 



