OF NAIADES. 399 



in his arrangement of the genera of shells ; but by generalizing 

 too much, in some instances he forced the barriers of Nature 

 and united genera that are totally distinct. The beautiful 

 simplicity of that great naturalist, however, was much more 

 favourable to the acquisition of knowledge than the endless 

 multiplicity of genera and species introduced by the moderns; 

 and the more we consider and scrutinise his arrangement, the 

 more does our wonder increase, that the same mind should 

 possess so vast a power of generalization, and such minute ac- 

 curacy in observing the details of specific difference. 



Note. — Since the foregoing observations were wTitten, a 

 paper on the Naiades by G. B. Sowerby, F.L.S., recommend- 

 ing a reunion of the whole family under one genus, and pro- 

 posing a new arrangement, has fallen under the observation of 

 the writer. The paper is in the Zoological Journal. Vol. I. 

 page 53, and is well worthy of perusal. 



vol. in. — 5 i 



