EXPLANATION OF PLATE IX. 

 Cardita granulata Say (p. 56). 



1, 2. Opposite Bides of a left valve, natuial size. 



3, 4. Two views of ii right valve, natural size and enlarged. 



Carditamkra ahata Conrad (p. 57). 



5, 6. Opposite sides oi' the largest valve observed. 



Carditamera Act'LEATA Conrad (p. 58). 



7, 8. View of the type specimen, natural size and enlarged. 



MvsiA PARlLis Conrad (p. fil). 



9. View of the original type specimen. 

 10, 11. Two views, enlarged, of another specimen. 



12. View of the hinge of the left valve, looking at the inner edge to see the elevation ot 



the teeth, enlarged. 



13. A similar view of the hinge of a right valve, greatly enlarged. 



Ceiama congregata Conrad (p. 65). 



14, 15. Opposite sides of an upper valve. 

 16, 17, 18. Three views of a lower valve. 



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