IV 



scientific institutions in this city and elsewhere. 

 It is therefore a curious circumstance in the his- 

 tory of American Conchology, that this singular 

 evidence of the author's acumen, zeal and indus- 

 try, should thus have existed for more than eleven 

 years, while but four of the numerous species 

 discovered and described by him, are known by 

 his names, either in the works of American 

 authors or in our collections. 



You will perceive, that the definitions as to 

 positions of the parts of the animal, in relation 

 to its shelly covering, now understood and 

 adopted by several eminent naturalists, whose 

 knowledge and opinions of their anatomical 

 structure are esteemed authentic, have been em- 

 ployed by Mr. RAFINESQUE ; thus, when the shell 

 is held so as to bring the apices or beaks upper- 

 most, and the ligament between them and the 

 eye, it presents also the dorsal or hinge margin : 

 this is nearly the natural position of the shell ; 



