U. S. DEPARTMENT OF COMMERCE 
Daniel C. Roper, Secretary 
BUREAU OF FISHERIES 
Frank T. Bell, Commissioner 
ADAPTATION OF THE FEEDING MECHANISM 
OF THE OYSTER ( Ostrea gigas ) TO 
CHANGES IN SALINITY 
By A. E. Hopkins 
From BULLETIN OF THE BUREAU OF FISHERIES 
Volume XLVIII 
Bulletin No. 21 
UNITED STATES 
GOVERNMENT PRINTING OFFICE 
WASHINGTON : 1936 
For sale by the Superintendent of Documents, Washington, D. C. 
Price 10 cents 
