PLATE LVII. 



PAGE 



Figs. 1, 2, 2a. Leda parilis (Conrad) 199 



1. Exterior of left valve. Upper Marlboro. 



2. Exterior of right valve. Same locality. 

 2a. Interior of same valve. 



Fig. 3. Leda parilis (Conrad) var 200 



Exterior of left valve. Probably from Woodstock. 



Figs. 4, 4a, 5. Leda Tvsoiyi n. sp 201 



4. Interior of right valve. Woodstock. 

 4a. Exterior of same valve. 



5. Exterior of smaller right valve. Woodstock. 



Fig. 6. NucuLA ovuLA Lea 202 



Exterior of left valve. Woodstock. 



Figs. 7, 7a, 8, 8a. Nucula potomacensis n. sp 202 



7. Interior of left valve. W^oodstock. 

 7a. Exterior of same valve. 



8. Exterior of right valve. Woodstock. 

 8a. Interior of same valve. 



309 



