82 Palaeontographica Americana 82 



PIRATE VII 



Figure Page 



1. Area trinitaria Gxxp'py 29 



"Exterior of left valve. Manzanilla, Trinidad"; after Gupp}'. 



2. Area trmtiaria Qu-p-py; " Posterior view of the shell with the valves united" ; after 

 Guppy. 



3. Area centrota Guppy 29 



"Pliocene, Trinidad"; after Guppy. 



4. Area bisulcata Lamarck 29 



Recent from Maranhao, Brazil. The inner margin of this valve is nearly smooth. 



5. Area bisulcata Lamarck; recent from Maranhao, Brazil; X 2; showing the toothed 

 margin of the young. 



6. Area rhomboidella Lea 30 



Claiborne Eocene of Claiborne, Alabama. 



7. Area rhomboidella Lea; Claiborne of Claiborne, Alabama; a full-grown specimen. 



8. Interior of the same. 



9. Area rhomboidella Lea; Claiborne Eocene of Claiborne, Alabama. 



10. Interior of the same. 



11. Area Vaughani Casey 31 



Claiborne Eocene of St. Maurice, Louisiana. The posterior margin is broken. 



12. Area Lesueuri Dall 32 



Oligocene of \'icksburg, Mississippi. This shows the double, beaded ribs of the 

 left valve. 



13. Interior of the same. 



14. Area Lesueuri Dall; Oligocene of Vicksburg, Mississippi; showing the beaded an- 

 terior and smoother central ribs of the right valve. 



15. Area Lesueuri Dall; Oligocene of Vicksburg, Mississippi. This shows the anterior 

 _^ sculpture as fig. 1 2 shows the posterior. 



16. Area Lesueuri DaW; Oligocene of Vicksburg, Mississippi; a large right valve. 



17. Area latidentata Dall 33 



Oligocene of Bailey's Ferry, Florida; old. 



18. Anterior end of the same; figured to show the convexity of old individuals. 



19. Area latidentata Dall; Oligocene of Bailey's Ferry, Florida: adult, slightly reduced. 



20. Area latidentata Dall; Oligocene of Bailey's Ferry, Florida; slightly reduced. 



21. Area aeompsa Dall 34 



"Oligocene of Alum Blufl, Florida; 20 mm."; after Dall. 



22. Area hypomela Dall 34 



Oligocene of Bailey's Ferry, Florida. 



23. Interior of the same. 



24. Area hypomela Dall; Oligocene of Bailey's Ferry, Florida; individual with narrow ribs. 



25. Umbonal view of the same. 



26. A rea lienosa S ay 35 



Miocene of Kingsmill, Virginia; a valve with arcuate ventral margin. 



27. Area lienosa Say; Miocene of North Carolina; a valve with the ventral margin 

 nearly parallel to the hinge. 



28. Interior of the same. 



