PLATE CVI. 



Figs. 1, 2. Arca (Scapharca) idoxea Conrad . 



1. Interior of left valve. St. Mary's River. 



2. Exterior of right valve. Same locality. 



PAGE 



389 



Figs. 3, 4. Arca (NoisTiA) incile Say 390 



3. Exterior of right valve. Darlington, South Carolina. Johns 



Hopkins University. 



4. Interior of left valve. Same locality. 



Figs. 5, 6. Arca (Barbatia) centexaria Say 391 



5. Interior of right valve. Jones Wharf. 



6. Exterior of left valve. Same locality. 



Fig. 7. Arca (Barbatia) marylaxdica Conrad 392 



7. Exterior of right valve. Plum Point. U. S. National Museum. 



Pig. 8. Arca (Barbatia) virgini.e Wagner 392 



8. Exterior of left valve of type specimen. Miocene of Virginia 



(Nansemond River?) 84 mm. Wagner Free Inst. Sci. (After 

 Ball.) 



