I am indebted to the politeness of Mr. Poulson, for 

 an opportunity to consult his library and collection, 

 in order to prepare the following Table of the spe- 

 cies of Naiades, inhabiting the North American 

 rivers. Most of those which have been described by 

 RAFiNEsauE, have been added by that author to Mr. 

 Poulson's valuable collections, with the names at- 

 tached to each] but I have considered some of these 

 as merely appertaining to varieties, and have given 

 them among the synonymes of the different species, 

 to which I think they properly belong. Mr. Poulson 

 deserves the thanks of Conchologists for the pains- 

 he has taken to rectify the confused nomenclature 

 of American Naiades, a task which has been attend- 

 ed with considerable labour and expense. 



