346 FOSSIL OSTEEIDiE OF NORTH AMERICA. 



PLATE XL. 

 OsTREA DiLUViANA Linn»us. (Page 295.) 

 Fig. 1. — Lateral view ; natural size. For other views see next plate. 

 OSTHKA CRENULIMARGINATA Gabb. (Page 294.) 

 2. — Interior view of the lower valve; normal size. After Gabb. 



OsTRE A ISOBUSTA Conrad. (Page 300.) 

 3, 4.— Opposite views of Conrad's type specimen. After Conrad. 



OsTREA PRUDENTiA White. (Page 299. ) 

 5, 6. — Opposite views of one of the type specimens; natural size. 



