V\hy are the denticulated Turbines, fuch ssfcxJentatiis, cmy^ 

 chmm,juneperi,.tridens, hidens, and otliers of tlie reverfed fpe- 

 cies of that genus, not removed to the genus Voluta ? 



The great refpe6l due to the abilities of the authors of the 

 tranfpofition of the fpecies here alluded to, will of courfe at- 

 tach very deferved merit to their labours in defining the 

 Li?mcvan fj^ecics of BritiJJj Tefiacea ; but how far they may 

 liave fully exemplified the Liniman definition in this inflance, 

 or in their divifion of Turbo and Helix muft, we believe, 

 Hill depend on private opinion. Where a Linncean Ipecies 

 has been clearly afcertained, the continuance of it in its ori- 

 ginal flation may be urged as abfolutely nccelTary, v/hethcr 

 it flri6lly conforms to the generic chara61;ers or not. But 

 it might be alked, would not this be fettering Icience ? It 

 mull; be obvious to every naturalifl; that the produ61:ions of 

 nature are fo varied, and yet fo interwoven, that all claflifica- 

 tion mull be arbitrary, fmce the fliades and gradations are fo 

 extremely nice. In fadt there is no podibility by the Liimaan 

 definition of thefe two genera, to afcertain to which many of 

 our fliells mod properly belong, and nothing can tend more 

 to prove this opinion to be well founded than the great dif- 

 ference obferved in the clafllfication of different authors, 

 fome placing thofe which have not the lead title to the cha- 

 radler of aperture contraEled, orbicular, intirc, in the genus 

 Tiu'bo and vice verja retaining in the Helix genus many with 

 the aperture as much or more intitled to thefe c]iara6lers. 

 If an intire aperture ( that is a detached marginal aperture ) 

 was fufficient to conftitute a Turbo without regard to fliape, 



and 



