19 



" sulcidens, Lam., 



" rarisulcata, " 



" Georgiana, " 



" glabrata, " 



" coarctata, " 



" carinifera, " 



" piirpurascens, " 



" purpureus, [to. Say, 



" JVEya complana- List., 



* I am indebted to Isaac Lea, Esq., of Philadelphia, for the advantage of 

 correcting my list of Naiades from his MS., " Synopsis of tlic family Naiades 

 of Lamarck," which he has been for some time engaged in, and which he has 

 recently communicated to the Ameiican Philosophical Soeicty. 



