78 PAbAEONTOGRAPHICA AMERICANA 78 



PI.ATE V 



Figure Page 



1. Area Adamsi (Shuttleworth) Smith; Miocene of the Natural Well, North Carolina; 

 X4; a well-preserved specimen. 



2. Area ovaliiia Dall 22 



"Oligocene of Bowden, Jamaica; 3.2 mm."; after Dall. 



3. Area ligniti/era Aldrich 23 



after Aldrich. 



4. Area ItgJiitifera Aldrich: after Aldrich 



5. Area Aldriehi Dall 23 



"Eocene of the Claiborne Sands; 8.2 mm." ; after Dall. 



6. Area taeniata Dall 23 



Pliocene of Shell Creek, Florida; X 2.3. 



7. Area taeniata Dall; Pliocene of Shell Creek, Florida; X 4. 



8, 9. Area asperula Dall 24 



"Macrodon asperula Dall; 8.5"; after Dall. 



10. Area sagrinata Dall •• 24 



"Longitude 6.0 mm."; after Dall. 



11. A rea profundieola Verrill and Smith 24 



"Type specimen; X 2"; after Verrill. 



12. Area profundieola \'errill and Smith; "The same. \'iew of the interior of a valve; 

 X2"; after Verrill. 



13. 14. Area ectoeomata Dall 24 



"46.0": after Dall. 



15, 16, 17. Area pterocssa E. A. Smith 24 



After Smith. The indicated dimensions of the figured specimen are: length 

 10 mm., height 55 mm. 



1 8. Area incile Say 25 



Miocene of Yorktown, Virginia; specimen with emarginate posterior. 



19. Interior of the same. The groove extending from the beak to the middle of the 

 hinge marks the posterior limit of the ligament. 



20. Area incile Say; Miocene of Kingsmill, Virginia: a less emarginate form. 



21. Interior of the same. 



22. Area ineile Say; Miocene of Yorktown, Virginia; emarginate form. 



23. Area ineile Say; Miocene of Kingsmill, Virginia; a specimen with no posterior 

 auriculation. 



24. Umbonal view of the preceding, showing the transverse grooves found in the cardi- 

 nal area in A^oetia. On this specimen the posterior boundary of the ligament area 

 does not show a marked groove. 



25. Anterior end of the same. 



26. Area limula Conrad 26 



Pliocene of the Croatan bed, North Carolina; typical form. This figure shows 

 the beaded interstitial ribs. 



