PLATE CV. 



Fig. 1. Arca (Scapharca) clisia Dall 



1. Interior of left valve. Nomini Cliffs, Virginia. 

 Museum. 56 mm. (After Dall.) 



PAGE 



386 



U. S. National 



Figs. 2-6. Arca (Scapharca) staminea Say 



2. Interior of left valve. Flag Pond. 



3. Interior of left valve of short variety. Same locality. 



4. Exterior of right valve. Same locality. 



5. Exterior of right valve. Dover Bridge. 



6. Interior of left valve. Peach Blossom Creek. 



387 



Figs. 7a, 7b. Arca (Scapharca) arata Say 



7a. Interior of right valve. St. Mary's River. 

 7b. Exterior of left valve. Same locality. 



388 



