PLATE 11. 



Page. 

 FlG. 1. OSTREA PATINA 18 



1, a. An internal view of an upper valve of the variety represented by lig. 3, e,f, of plate 10. 



1, b. An external view of same. 



Fig. 2. Gryfiuea vesicularis ? ^0 



■2, a. A side view of the under valve, showing convexity. 



2, b. Exterior of the upper valve of same. 

 U, c. Interior of last. 



Fig. 3. Ostrea patina, war. B 18 



3, «. An internal view of au under valve. 

 3,6. Exterior of same. 



Fig. 4. Ostrea patina, var. C 18 



4, «. An upper-side view of the type-specinieu of the var., with the two valves united. 

 4, b. Au under-side view of same. 



