PLATE CIX. 
PAOE 
Figs. 1-3. DisciMiscA LuouBRis (Conrad) 402 
la. Exterior of dorsal valve. Jones Wharf. 
lb. Interior of the same. 
2a. Exterior of dorsal valve of another specimen. Same locality. 
2b. Interior of the same. 
3 Interior of ventral valve. Same locality. 
Pigs. 4, 5. Theonoa gi-omerata n. sp 406 
4a. Upper surface of a large specimen. St. Mary's River. x % 
4b. Another view of the same. x 16/5 
4c. Under surface of the same. x % 
5a. Upper surface of a small specimen. Same locality. X % 
5b. Another view of the same. x 16/5 
Figs. 6-8. Idmonea ( ?) expansa n. sp 404 
6. View of a young specimen. Cove Point. x 16 
7. View of another young specimen. Same locality. X 16 
8. A large specimen from the same locality and attached to the same 
shell, showing the pinnate arrangement of the zooecia adopted 
in later stages of growth. X 16 
