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SPECIES XLVIII. Obovaria pachostea ( Unio 

 pachostea.) 



Shell extremely thick, ventricose, rounded 

 and attenuated or flexuous inferiorly; apices 

 somewhat prominent ; epidermis brown, slightly 

 wrinkled ; nacre pale violet colour ; border flexu- 

 ous. Medial breadth T 9 5 diam. f^ of the 

 length ; oblique axis f of the breadth. 



A remarkable species, with an interior cavity, 

 very small and wrinkled ; broad cavity under the 

 tooth ; this species approaches the sub-genus 

 Sintoxia, genus Obliquaria, its axis being 

 somewhat oblique, or having a slight posterior 

 dilatation. Found in the Kentucky. Length 

 three to four inches ; lamellar tooth short, vertical, 

 obtuse ; cardinal tooth very large and broad, fur- 

 rowed ; fossule visible. 



SPECIES XLIX. Obovaria stegaria (Unio 

 stegaria.) 



Shell thick, ventricose, rounded inferiorly, 

 slightly imbricated, by the large separated wrin- 

 kles ; apices slightly prominent; epidermis brown ; 

 nacre white ; inferior breadth i-| o f the length, 

 diam. f of the breadth ; axis medial. 



