PLATE LXIV. 



PAGE 



Figs. 1-6. Arca (Noetia) ponderosa Say 205 



1. Interior of left valve. Wailes Bluff. 



2. Exterior of right valve. Same locality. 



3. Interior of same. 



4. Exterior of left valve. 



5. Interior of left valve of larger individual, same locality. 



6. Exterior of same. 



Figs. 7-10. Arca (Scapharca) transversa Say 206 



7. Interior of left valve. Wailes Bluff. X 2y 2 



8. Exterior of right valve. Same locality. X2y 2 



9. Interior of same. 



10. Exterior of left valve. 



