PLATE LXXXVI. 
PAGE 
Fig. 1. Cardium (Cekastoderma) laqueatum Conrad 319 
1. Exterior of left valve. Jones Wharf. x % 
Fig. 2. Cardium (Cerastoderma) leptopleurum Conrad 320 
2. Exterior of right valve. Plum Point. 
Fig. 3. CARMt'M (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. 
Pigs. 7a, 7b. Cardium (L-bvicardium) mortoni Conrad 323 
7a. Exterior of right valve. Jones Wharf. U. S. National Museum. 
7b. Interior of the same valve. 
