HELIX. 



GENERIC CHARACTER. 



Shell univalve, free, subglobular, convex or somewhat 

 conic. Aperture entire, wider than long, more or less ob- 

 lique, a little contracted by receiving a part of the convex- 

 ity of the preceding volution, which also widely separates 

 the lips. 



Animal hermaphrodite with four retractile tenticula, 

 which are filiform or cylindrical : anterior pair short ; pos- 

 terior pair much longer, oculiferous at tip : spiracle on 

 the right side of the neck, near the anus, and another pore 

 which contains the organs of reproduction : they respire 

 air only. 



OBSERVATIONS. 



Tliis is a universal, and if I may use the expression, a 

 cosmopolite genus. The species are exceedingly nume- 

 rous ; in favoumble situations some of them are multiplied 

 almost to infinity, and become very destructive to cultiva- 

 ted plants. So formidable are they in this respect in some 

 parts of Europe, that many devices are practised to destroy 

 them. In North America they do not multiply to an inju- 

 rious extent and I have never known a garden or an or- 

 chard, in w^hich their depredations attracted the preven- 

 tive attention of the cultivator. 



They attain to their greatest magnitude and beauty in 



PLATE XIII, 



