Plate I, 



FIG. 1.— AN UNDREDGEU PuRTIij[J UF THE KANKAKEE RIVER, FILLED WITH VALUABLE SPECIES 

 OF MUSSELS, SHOWING CONDITIONS UNDER WHICH THEY FLOURISH, 



."-^ 





fig. 2.— a dredged portion of the kafj.-.a... ££ r .ek ;,.l the mussels here were 

 Killed by dredging, and not one can live under the artificial conditions 

 here established. 



