/¥ 



7 



Transactions of The Academy of Science of St. Louis, 



VOL. VII. No. 1. 



A STUDY OF THE UNIONID^ OF ARKANSAS, 

 WITH INCIDENTAL REFERENCE TO THEIR DIS- 

 TRIBUTION IN THE MISSISSIPPI VALLEY. 



By 



R. ELLSWORTH CALL. 



Issued January 3d, 1895. 



