Io8 BULLETIN OF THE BUREAU OF FISHERIES. 



Page. 



VII. Investigations on the upper Mississippi River 187 



VIII. Economic applications 189 



Protective laws 189 



Selection and maintenance of a fish supply 190 



The best seasons for infections 191 



The mussel supply igi 



Rearing and distributing young mussels 192 



IX. Conclusion 193 



Bibliography 195 



Explanation of plates 198 



