EXPLANATION OF PLATE IX. 
CARDITA GRANULATA Say (p. 56). 
FIGs. 1,2. Opposite sides of a left valve, natural size. 
3,4. Two views of a right valve, natural size and enlarged. 
CARDITAMERA ARATA Conrad (p. 57). 
Fics. 5,6. Opposite sides of the largest valve observed. 
CARDITAMERA ACULEATA Conrad (p. 58). 
FIGs. 7,8. View of the type specimen, natural size and enlarged. 
MYSIA PARILIS Conrad (p. 61). 
Fic. 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 of 
the teeth, enlarged. E 
13. A similar view of the hinge of a right valve, greatly enlarged. 
CHAMA CONGREGATA Conrad (p. 65). 
Fics. 14, 15. Opposite sides of an upper valve. 
16, 17,18. Three views of a lower valve. 
