OBSERVATIONS. 



This species is more transverse than usual in this ge- 

 nus ; it is altogether destitute of lateral teeth, and the pos- 

 terior muscular impression is remarkably slender. It is 

 superior in point of size to either the orbiculatum, or ra- 

 dicttiim, Nob., though proportionally somewhat thinner. 

 I obtained a specimen on the coast of Georgia, that is some- 

 what worn ; its colour is whitish, a little tinged with yel- 

 lowish. 



REFERENCE TO THE PLATE. 



The middle fgures represent the exterior, interior and dorsal aspects of the 

 ehell. 

 PLATE XXVIII. 



AMPHIDESMA iEQUALE. 



SPECIFIC CHARACTER. 



Left valve with remote grooves instead of lateral teeth. 



SYNONYM. 



A. JEquALE. Nobis. Jour. *Q.cad. Nat. Sc. vol. 2, p. 307. 



DESCRIPTION. 



>S^6// orbicular-triangular, a little oblique, polished, white, 

 with minute and numerous wrinkles towards the margin. 



