138 LAND AND FRESH-WATER MOLLUSKS. 
lists. This species reaches a higher elevation 
than any other, being found high up on moun¬ 
tain-sides ; in the Alps it attains to the region 
of perpetual snow. At this great altitude the 
shell is smaller, and the spire more elevated, and 
is the variety alpina (PI. VII., fig. 62a). 
Heltx iulchella —(the Pretty or White Snail) 
(PI. VIII., fig. 67)—is another of the little-isms 
of molluscan life. The animal is milk-white, and 
its black eyes contrast strongly with the trans¬ 
parency of the upper tentacles. The shell par¬ 
takes of the colour of the animal, is rather opaque 
and depressed in form; there are three and a 
half rounded whorls, the last one exceeding the 
rest of the shell in size: the circular aperture 
has a very thick and strongly reflected margin, 
forming a complete peristome; the umbilicus is 
large and deep; the diameter is a tenth of an 
inch. 
_ =jg3 ; 3 in ^ The accompanying figure repre- 
^ sents the striated horny jaw of this 
Fi g- 22.^ Jaw of pttle beauty. The number of 
teeth far exceeds in number those 
of Helicella cellaria , which possesses a shell many 
times the size of this minute species; the dental 
formula is 15 OP " = 1860. 
o O 
It is widely distributed throughout Britain and 
Europe, and ranges to Siberia, and is found in 
Madeira and the Azores. 
