418 FOSSIL OSTREID^ OF NORTH AMERICA. 



PLATE LXXVI. 



Fig. 4. — Diagram of the soft parts of the Amcricau oyster, showiug the extent of the 

 generative organ Gen, and the courses of the efferent ducts of the left side, 

 the main duct opening at the point ov below the adductor muscle miia ; ii, 

 heart; mt, mantle; P, palps; G, gills. 



5. — Twenty days' old spat of the American oyster viewed from above, natural 

 size. 



C. — Forty-four days' old spat, natural size. 



7. — Forty-eight days' old spat, natural size. 



8. — Young spat oyster, seventy-nine days old. 



9. — Young spat oyster, eighty-two days old. 



10. — Young oyster, 2^ to 3 months old, from inside of a wreck at Cape May, New 

 Jersey. 



