PLATE LX. 



PAGE 



Figs. 1-4. Aligena elevata ( Stimpson) 202 



1. Interior of left valve. Wailes Bluff. X 11 



2. Exterior of same. 



3. Interior of right valve. 



4. Exterior of same. 



Figs. 5, 6. Mytilus hamatus Say 203 



5. Exterior of valve. Wailes Bluff. X 1% 



6. Interior of a smaller valve. X 1% 



Figs. 7-11. Uisrio complaxatus (Solander) Dillwyn 203 



7. Interior of valve of Recent form. X l r \ 



8. Interior of right valve, mouth of Back River. 



9. Exterior of same. 



10. Interior of left valve. Same locality. 



11. Exterior of same. 



K,r, 



