69 



straight, wrinkled \fossule visible ; cardinal tooth 

 striated. 



SPECIES LXVIII. Obliquaria atroviolacea 

 (Unio atroviolacea.) 



Shell somewhat thick, convex, elliptical, oval, 

 and posteriorly attenuated ; epidermis blackish, 

 almost smooth ; nacre very deep violet colour ; 

 border dull brown. Length ^ diam. axis ^ 

 of the breadth. This species belongs to the 

 sub-genus Ellipsaria, Vide page 35. 



A handsome species with a fine nacre; breadth 

 three inches found in the Kentucky, &c. la- 

 mellar tooth carinated straight jfossule confluent; 

 muscular impressions deep ; teeth wrinkled. 



SPECIES LXIX. Obliquaria Cliffordiana 

 (Unio Cliffordiana.) 



Shell thick, ventricose, oval, rounded ; very 

 long posteriorly ; sloped posteriorly ; nacre nearly 

 smooth, blackish, pale purple. Length diam. 

 f- -axis i of the breadth. This species belongs 

 to the sub-genus Plagiola. Vide page 32. 



In the museum of Mr. Clifford ; found in the 

 Kentucky. Breadth three inches ; lamellar tooth 

 7 



