U. 0. KATtONAL MUli 



ICO eo 



PROCEEDINGS. VOL. XXU PL. XVUI 



!■ 



IP'' 140 120 



100 80 60 40 20 



Map showing the Distribution 



JO 40 60 80 100 120 140 160 



^'«'-'' FrtESH-wATER Mussels 



