PLATE LIII. 



PAGE 



Figs. 1-4. Coebula conteacta Say 193 



1. Interior of left valve. Wailes Bluff. X 5 



2. Interior of right valve. 



3. Exterior of left valve. 



4. Exterior of right valve. 



Figs. 5, 6. Mya arenaria (Linne) 194 



5. Interior of right valve. Wailes Bluff. 



6. Exterior of left valve. 



259 



