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SPECIES XXIII. Obliquaria lineolata (Unio 

 lineolata.) 



Shell nearly round, thick, slightly ventricose, 

 somewhat truncated posteriorly ; epidermis red- 

 dish, slightly wrinkled, with brown lines ; nacre 

 white. Length diam. ^ axis ^ of the 

 breadth. Apices somewhat prominent. 



Found at the falls of the Ohio ; breadth about 

 two inches ; posterior portion truncated, plane, 

 narrow; muscular impressions deep rugose; la- 

 mellar tooth short, thick, carinated, rugose, almost 

 straight. 



Second Sub-genus^- ELLIPSARIA. 



Axis extramedial ; lamellar tooth straight ; 

 ligament straight ; shell elliptical. 



SPECIES XXIV. Obliquaria ellipsaria (Unio 

 ellipsaria.] 



Shell elliptical, with a posterior diagonal angle; 

 epidermis somewhat wrinkled, reddish olive; 

 nacre white ; axis almost lateral. Length 

 diam. | axis j of the breadth. 



Var. l.fusca entirely brown ; breadth 

 about five inches ; no fossule ; found in 



