PLATE LXXXIX. 
PAGE 
Figs. 1-3. Aligena .'equ.'^ta (Conrad) 333 
1. Interior of left valve. Jones Wharf. 
2a. Interior of left valve. Miocene of Virginia. U. S. National 
Museum. (After Dall.) 
2b. Exterior of the same valve. (After Dall.) 
3. Interior of right valve. Miocene of Virginia. U. S. National 
Museum. (After Dall.) 
Pig. 4. Aligena .^quata var. nuda Dall 333 
4. Exterior of right valve. Plum Point. 
Figs. 5a, 5b. Aligena pustulosa Dall 334 
5a. Interior of left valve. Oligocene of Oak Grove, Florida. U. S. 
National Museum. (After Dall.) 
5b. Exterior of same specimen. (After Dall.) 
Figs. 6a, 6b. Diplodonta acclinis Conrad 334 
6a. Interior of right valve. Caloosahatchie beds. U. S. National 
Museum. (After Dall.) 
6b. Exterior of same valve. (After Dall.) 
Figs. 7, 8. Diplodonta shilohensis Dall 335 
7. Exterior of left valve. Jones Wharf. 
8. Interior of right valve. Same locality. 
Figs. 9, 10. Diplodonta subvexa (Conrad) 335 
9. Interior of right valve. Flag Pond. 
10. Exterior of left valve. Same locality. 
