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POPULAR CONCHOLOGY. 



41. Helicina. — Shell flattened ; mouth 

 semicircular, closed by a horny operculum ; lip 

 thickened, and columella often also thickened. 



Animal, having a head furnished with a pro- 

 boscis, and two tentacula, with eyes at the base 

 on tubercles; foot rather short. — There are 

 19 species recent, and 1 fossil. 



Some species feed on trees, and others on 

 the ground ; they are natives of the West In- 

 dies and other countries of the torrid zone. 

 The operculum, which is permanently attached 

 to the foot, is not spirally formed, but in con- 

 centric layers.— The //. viridis, from St. Do- 

 mingo, is of a smooth shining green colour. 



42. Pupa. — Shell cylindrical ; 

 spire long; aperture irregular, 

 toothed, with the lips thickened, 

 and unconnected at the upper part, 

 the plaits on the left lip interven- 

 ing. Animal like the Helix. — 

 There are 56 species recent, and 2 fossil. 



