Bull. U. S. B. F., 1914. 



Plate LXXX 



Fig. 12. — Shells of mussels rt'arcd in a pund from clochidia artificially infected upon fish. The buttons were cut from the 

 shells within two years from the date of infection. The quality is cood, but the shells are yet too thiu for commercial uses. 

 (See text, p. 401.) 



-Ponds used for experiments in cultivation of fish and mussels. The mussels of ficure 12 were reared in tlie pond in 

 right foreground. Buftalolish are being reared in pond in left background. 



