Cincinnati Society of Natural History. 



terior cicatrices distinct, well impressed, that of the retractor pedis 

 being more distinctly marked than the posterior adductor, and impressed 

 at end of lateral teeth ; pallial cicatrix faintly impressed and some- 

 what sinuous ; cavity of the beaks shallow and rounded, with numer- 

 ous, linear, minute muscular impressions posterior to the base of the 

 cardinals and often upon them ; epidermis straw yellow or honey 

 brown in color, the young specimens occasionally found with hair like 

 green rays which are, however, confined to the umbonal slope ; nacre 

 pure white and somewhat irridescent posteriorly. 



Geographical distribution. — This shell ranges from western 

 Pennsylvania to the Alabama river, Alabama and westward to Iowa 

 and Minnesota. In the rivers of the middle Ohio drainage and in 

 Iowa it is a common and beautiful species. The animal is of a deep 

 salmon color, which character should assist in separating it from its 

 congeners. 



Cincinnaii, January 26, 1896. 



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