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SPECIES LXIV. Tremesia patelloides. 



Principal valve rounded, somewhat conical, 

 striated concentrically, and tessellated by curved 

 oblique transversal striaB ; aperture round ; small 

 valves smooth ; inferior valve oblique, oboval ; 

 animal striated flexuously beneath, acute oppo- 

 site the inferior valve ; head truncated. 



Animal very singular ; which I announced in 

 the American Monthly Magazine, last year, 

 under the defective name of Notrema. It is 

 found in the lower part of the river Ohio, attach- 

 ed to the stones by the base, like the Patella ; 

 shell brownish fawn coloured ; opercular valve 

 brown, glossy, movable ; diam. about one inch, 

 height half an inch. 



SPECIES LXV. Mytilus recurvus. 



Shell oboval, cuneiform, recurved, with longitu- 

 dinal striae of three lengths ; epidermis blackish ; 

 nacre violet ; the beaks oblique, with a decurrent 

 angle on each side ; the inferior and interior bor- 

 der, striated, crenulated. Breadth T 7 2 - diam. fa 

 of the length. 



Found in the Mississippi near New Orleans 



