I am indebted to the politeness of Mr. Pqulson, 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 
Rafinesoue, 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. 
