42 



SPECIES XXXIV. Obliquaria nodulata (Unia 

 nodulata.) 



Shell thick, ventricose, nodulated, sloped pos- 

 teriorly, and truncated vertically ; linear longitu- 

 dinal tubercles upon the posterior dilatation ; 

 epidermis almost smooth, reddish brown ; nacre 

 iridescent. Length | diam. f axis of the 

 breadth. Breadth one inch and an half. 



Found in the Kentucky, four separate nodo- 

 sities distant ; cardinal tooth thick, striated; mus- 

 cular impressions deep ; lamellar tooth carinated. 

 It resembles the obliquaria retusa; both have the 

 lamellar tooth very slightly curved. 



SPECIES XXXV. Obliquaria quadrula(Unio 

 quadrula*} 



Shell very thick, somewhat ventricose, with an 

 oblique longitudinal elevation ; oblique furrow 

 and sinus posteriorly; epidermis brown, wrinkled; 

 wrinkle? striated and tuberculated anteriorly ; 

 nacre white, roseate on the borders. Length f 

 diam. 4 axis | of the breadth. Breadth two to 

 three inches. 



Common in the Ohio ; with some oblong trans- 

 versal tubercles on the elevation ; shell somewhat 

 sinuous on the disk ; lamellar tooth short, thick* 



