EXPLANATION OF PLATE IL 



OSTKEA VlKGINIANA (imel. (p. 27). 



Figs. 1, 2. Inner and outer surfaces of a narrow form. Upper valve. 

 .3, I. Similar view.i of a rurved form of upper valve. 

 5, (i. Interior and pnilile views of a lower valve of tbe ordinarv form. 



7. ('oi>y of Mr. (Jalib's figure of O. Maiirhiusi.'i IVom vol. 4, Jour. Acad. Nat. Sci.,.1'1. 67. 



Pi-XTEN Maiiisonus .Say (p. 30;. 



I"i(i. K. View of a fragment from a large .shell. 



(See other figures on PI. IV.) 



148 



