PLATE LXXXVI. 



PAGE 



Fig. 1. Cardium (Cerastoderma) laqueatum Conrad 31& 



1. Exterior of left valve. Jones Wharf. x % 



Fig. 2. Cardium (Cerastoderma) leptopleurum Conrad 320 



2. Exterior of right valve. Plum Point. 



Fig. 3. Cardium (Cerastoderma) craticuloide Conrad 320 



3. Exterior of left valve. Plum Point. 



Fig. 4. Cardium (Cerastoderma) calvertensium n. sp 321 



4. Exterior of right valve. Governor's Run (lower bed). 



Fig. 5. Cardium (Cerastoderma) patuxentium n. sp 322 



5. Exterior of right valve. White's Landing. 



Figs. 6a, 6b. Cardium (Fragum) medium Linne 322 



6a. Interior of right valve. St. Mary's River. U. S. National 



Museum. 

 6b. Exterior of the same valve. 



Figs. 7a, 7b. Cardium (L.^vicardium) mortoni Conrad 323 



7a. Exterior of right valve. Jones Wharf. U. S. National Museum. 

 7b. Interior of the same valve. 



