CHAPTER LXIII: THE GLASSY SNAILS 



Family Vitrinid.^ 



Genus VITRINA, Drap. 



Shell thin, glassy, of few whorls; animal too large to be 

 withdrawn completely; tail short; mantle reflected over shell. 

 Jaw and radula simple. Species about one hundred, terrestrial, 

 living in moist situations in temperate or cold regions. These 

 mollusks live in moist situations on earth or stones, sometimes 

 crawling on snow. They are lively and jump when touched, and 

 wrap themselves for protection in the folds of the mantle. They 

 are herbivorous, but occasionally like the taste of flesh. 



PfeifFer's Glassy Snail (^. Pjeifferi, Newc.) looks like a slug 

 wearing a glassy, greenish, three-whorled shell much too small to 

 fit its body. The large, flaring lip is thin and plain. This snail 

 lives in high altitudes in the western states. Diameter, \ inch. 



Family ZoNiTiDy^ 



Shell a depressed spire, thin, transparent, with sharp, simple 

 peristome; umbilicus present; animal able to withdraw into the 

 shell. Foot with a mucus pore; jaw not ribbed; mantle lobed, 

 but rarely reflected. 



The glassy shells of these pitted snails, the presence of 

 the mucus pore, and the thin, plain lip, set them apart from 

 the Helicidre. They inhabit dark, damp situations, have an onion 

 odour and probably a taste disagreeable to birds. When first 

 hatched they exhibit cannibal tendencies. A hungry specimen 

 will eat a weaker brother, shell and all. They are numerous in 

 Europe and America. 



Genus ZONITES, Montf. 



A European and American group, less showy in size and 

 colouring than Nanina, and fewer in number of species. Epi- 



254 



