PLATE -tO. 



Page 



Fig. 1. Ostisea subtkigoxai.is ? 510 



I, a. An internal view of an upper valve. 



1, b. Interior of a lower valve. 



1, c. Exterior of a lower valve. 



1,(7. Exterior of an upper valve united to an imperfect lower valve. 

 FlG. 2. OslKl'.A GLABRA 509 



2, it. External view of a lower valve (type-specimen). 

 2, b. Interior of same. 



2, c. An upper view of another specimen, consisting of the two valves united. 

 2,d. An under-side view of last. 



Fig. 3. Cobbula subtrigonalis 529 



3, n. A dorsal view of a left valve (type-specimen). 



3, b. An outside view of same. 



Fig. 4. CoiiBULA pkhuxdata 530 



4, a. An outside view of a left valve (type-specimen). 

 4,6. The same of a smaller specimen. 



4, c. The same of a right valve. 



4, d. A hinge and internal view of a weathered left valve. 



Fig. 5. Corbicula cythekikormis , 520 



5, a. A left-side view of type-specimen. 



5, b. An opposite view, a more rounded specimen. 



5, i: A posterior view of the type-specimen. 



5, rf. A right-side view of a smaller, more rounded specimen. 



5, e. A large, imperfect specimen, probably of this species. 



Fig. C. Corbicula occidektalis 521 



i'i, (I. A right-side view of the type-specimen. 



6, /;. An anterior view of same, the two valves being accidentally compressed together, so as 



to appear too acuminate below, 

 li, c. A left view of an internal east, showing muscular and pallial impressions and the beak of 

 the opposite valve projecting above. 



