84 Palaeontographica Americana 84 



PIRATE VIII 



Figure Page 



1 . Area protrada Rogers 36 



After Rogers. 



2. Area protraeta Rogers; after Rogers. 



3. Area secticostata Reeve 36 



Recent from Florida; interior of a right valve. The fluting of the ventral mar- 

 gin is obscured by the illumination. 



4. Area seetieostata Reeve; recent from Florida; umbonal view. 



5. Area seetieostata Reeve; recent from Florida; a specimen with arcuate ventral margin. 



6. Area dodotia Dall 37 



Oligocene of Oak Grove, Florida. The ventral margin is fluted. 



7. Area dodona T>a\\; Oligocene of Oak Grove, Florida: left valve of a large specimen. 



8. Right valve of the same. 



9. Umbonal view of the same. Because of the age of the individual the cardinal 

 grooves are unusually numerous. 



10. Area dodona Dall; OHgocene of Oak Grove, Florida; exterior of a valve whose cen- 

 tral ribs are beaded. 



