Our British Snails 37 



but the last is much smaller than the others. 

 The tentacles in the first are long, and in the 

 third short ; while in Rogcrsi the upper pair 

 are long and the lower very short. It is also the 

 most glossy of all. If put in a box with other 

 small shells it will clean them by cannibalism. 



Vitrea {Polita) alliaria, i.e. smelling of garlic. — 

 Often confused by quite good conchologists with 

 the preceding species, but the bcdy is much darker, 

 and the shell smaller and less white below than 

 either cellaria or helvetica. The always present 

 smell is said to protect it from ants. Common, 

 but local, and often a pest in greenhouses and 

 ferneries. 



Vitrea [Polita) nitidula. — Common. Less glossy. 

 Marked expansion of the last whorl as it nears 

 the mouth. 



Vitrea (Polita) pura. — Like nitidula but smaller, 

 and edge of mantle white instead of dark. More 

 common in the north. Shell thin and dull white. 



Vitrea {Polita) radiatula. — Never abundant. 

 Striations on shell give it a radiated appearance 

 when magnified. Animal nearly black. 



Vitrea crystallina. — The smallest of the genus. 

 Shell transparent, pearly white. Umbilicus (i.e. 

 the opening in the centre of the underside 

 showing the whorls) very narrow. Subterranean 

 in habit. Whorls, four ; whereas H. pura has 

 five ; also more compressed. 



Euconulus fulvtis. — Distinctively pyramidal in 



