GONCHOLOGY. 



by writers as specifically distinct, are in reality of the same individual 

 species, and should be restored to this parent stock. We readily ad- 

 mit that at first view there may appear an obvious dissimilarity in 

 the aspect of these shells : a difference in their colours, in the form and 

 disposition of their bands, spots, and lineations, and other less 

 material points that may seem to justify their separation in the 

 minds of those who have not regarded with very minute attention the 

 sportiveness of nature in such particulars. But with so many advan- 

 tageous means of comparison as the more abundant species of terres- 

 trial Helices afford, in this and every other country, the experienced 

 Conchologist will be less likely to be deceived ; he will regard them 

 with due caution, and may perhaps be inclined to reduce the number 

 of the species, even where to common observation there may still 

 appear some necessity for constituting species in greater number 



Linnaeus has described the type of this species, his Helix 

 Perversa, as having the wreath of the whorls turning in the reverse 

 or contrary direction from that of other univalves. This is not, how- 

 ever, uniformly the case with Helix Perversa, for as they naturally 

 wreath spirally from the mouth, and that the mouth is sometimes 



* This is most amply demonstrated in several different kinds of the 

 striped or banded Helices. Helix Nemoralis, found throughout Europe 

 and in great abundance in Britain, is truly illustrative of this particular. 

 These vary from a white to a paler or deeper yellow, sometimes without 

 any band, sometimes with a single band, two bands, or a greater number to 

 the amount of five or more. Sometimes the lines are narrow ; at others 

 broad, and so closely placed that the yellow appears only in the form of ex- 

 tremely fine spiral lines, and even this in others is wholly wanting. Vide 

 Donovan's British Shells, vol. 2. tab. 13. Helix Zonakia, vol.2 t. 65, 

 affords us other interesting examples, and so likewise the varieties of Helix 

 Hortensis. Vide Donovan's Br. Shells. 



