392 OHIO STATE ACADEMY OF SCIENCE. 



Quadrula cicatricosa (Say, Unio), varicosa Lea. 



Ohio River. 

 Quadrula pilaris (Lea, Unio). 



Ohio River at Cincinnati. 

 Quadrula ebena (Lea, Unio). 



Ohio River. 

 Quadrula pyramidata (Lea, Unio). 



Ohio River and tributaries; large and heavy specimens in 

 the Tuscarawas River. 

 Quadrula plena (Lea, Unio). 



Ohio River. 

 Quadrula obliqua (Lamarck, Unio). 



Ohio River, and some tributaries. 

 Quadrula solida (Lea, Unio). 

 Ohio River; Scioto River. 



These last four species are closely related to each other, and 

 should be revised. 

 Quadrula trigona (Lea, Unio). 



Both drainages, not common. 

 Quadrula rubiginosa (Lea, Unio). 



Over the state, generally common. — In some specimens from 

 various rivers (Ohio, Tuscarawas, Tiffin), where the 

 gonad was for the most part a testis ("males"), a few 

 acini were found to be ovarian, containing ova. 

 Quadrula coccinea (Conrad, Unio). 



Over the state, variable. In the Tuscarawas River is a form 

 higher than the "typical" one, resembling kirtlandiana 

 in shape, but with the soft parts quite different, and 

 usually with a few undulations in the middle of the 

 disks; it may represent a variety. 

 Quadrula coccinea paupercula Simpson. 



St. Lawrence drainage; probably in the state. 

 Pleurobema clava (Lamarck, Unio). 



Both drainages; e. g. in the Maumee; not in the Cuyahoga 

 River, t. Dean. 

 Pleurobema bournianum (Lea, Unio). X 



Scioto River; Ohio River at Cincinnati (Byrnes). 

 Unio crassidens Lamarck. 



Ohio River, common ; Scioto River. 

 Unio gibbosus Barnes. 



Over the state, common and variable in regard to size, shape 

 and color of the nacre: dark purple to salmon to white 

 (the latter = arctior Lea) ; a very small form, with the 

 beaks more anterior, is in Lake Erie. 

 Unio tetralasmus camptodon Say. 



Ohio River at Cincinnati; Great and Little Miami Rivers. 



