in that species the transverse stride are stated to be une- 

 qual, and its inner margin is not said to be of a different 

 colour ; a character which in our shell is very obvious. 

 Barnes read a description of it to the Lyceum of Natural 

 History of Nev\^ York in 1823 (see Silliman's Journal, Vol. 

 6, p. 364.) 



It does not reach the attributed magnitude of M. crena- 

 tus, Lam. a species v\^hich vv^as supposed by that author to 

 inhabit the coast of Carolina ; but if either of the different 

 figures of Lister, Sow^erby, or that of the Encyclopoedia 

 Methodique is a tolerably correct representation of it, I 

 have certainly not met with it. 



REFERENCE TO THE PLATE. 



The plate exhibits the inner and outer views of a valve. 

 PI. 50. 



