38 BUI.LETIN 5 3o8 



132 FOSSIL SHELLS. 



radiating striae, and numerous tubular processes : 

 apex inclinde towards the shorter side ; within livid- 

 brown, polished : ciip-shaped appendage brown near 

 the apex, margin pure white, and distinct from the 

 side as far as the submargin. 



Calyptr^E costata, nobis, Silliman's Journal, 

 vol. 2, p. 40, belongs to this genus. In Mr. Finch's 

 collection are fine specimens of this species. 



FISSURELIvA. 



F. redimicula. PI. viii. fig. r. Ovate-oval a lit- 

 tle oblong, conic-convex, with approximate longi- 

 tudinal striae ; foramen ovate-oval, inclined. 



Description. Longitudinal striae slender, nume- 

 rous, granulated, approximate ; the granulations of 

 the striae give the appearance of concentric obso- 

 lete lines : aperture, inner margin crenate ; thick- 

 ened inner margin of the foramen truncate at one 

 end. 



Longest diameter one inch and a half. 



I am not acquainted with the F. peruviana, Lam. 

 and the description of that shell will not enable 

 me to judge satisfactorily of its degree of affinity 

 with the present species. 



OSTREA. 



I. O. compressirostra. PI. viii. fig. 2. a. In- 

 ternal view. b. External view. Shell sinistral, 

 [J. A. N. S., Phila., ist Ser., Vol. IV, 1824.] • 



