go PALAEONTOGRAPHICA AMERICANA QO 



PlvATE XI 



Figure Page 



1. Area campyla Dall 47 



"Caloosahatchie beds; side view; Ion. 37 mm."; after Dall. 



2. Area campyla Dall; "Umbonal view, showing tortuosity of the valves; Ion. 37 

 mm."; after Dall. 



3. Area catnpyla Dall, var. aeretea Dall; "Pliocene of Shell Creek, Florida; 34 mm."; 

 after Dall. 



4. A^ca transversa Say 47 



Recent from Florida; showing the nodtilous anterior and flat central ribs of the 

 right valve, and the extension of the left valve beyond the right. 



5. Left valve of the same, showing the rounded, nodulous ribs. 



6. Interior of the left valve. 

 Area triphcra Dall 4^ 



"Caloosahatchie Pliocene; 18 mm."; after Dall. 

 A rea halidonata Dall 49 



"Oligocene of Bowden, Jamaica; 56 mm."; after Dall. 

 A rea consobrina Sowerby 49 



After Sowerby. 



10. Area consobrina Sovievhy; after Sowerby. 



11. Area inequilateralis Guppy SO 



After Guppy. 



12. Area iucquila/cralis Gvcp-py; after Guppy. 



13. Area aetinophora Dall SO 



"Oligocene of Monkey Hill, Panama Railway; 46 mm."; after Dall. 



14. Area donaeia Dall S^ 



"Oligocene of Bowden, Jamaica; 6.5 mm."; after Dall. 



15. Area Deshayesiil^^rA&y S o 



Recent from Guadeloupe. The peripheral part has been modified in the en- 

 graving process but the outline is approximately correct. 



16. Umbonal view of the same. 



17. Area Deshayesiil^QxA'e.y; young; recent from Jamaica. Figured to show the pos- 

 terior auriculation of the young. 



18. Umbonal view of the same. 



19. Area auriculata Lamarck 50 



Recent from Florida. The degree of auriculation varies. It is greater in the 

 young. 



