LAND SNAILS. 
103 
actively in motion at all times of tlie year, and 
not more frequently at other seasons than during 
the winter months. I, as well as many others, 
have seen this hardy creature creeping upon the 
snow. 
Bouchard-Chautereaux, a French conchologist, 
who made the habits of the land and fresh-water 
snails of his country objects of especial study, 
says that the eggs are not laid until towards the 
close of the year, and that the young attain their 
adult condition at the end of the eighth or tenth 
month ; and he is of opinion that they do not live 
longer than from twelve to fifteen months. 
Genus Helicella (diminutive of Helix, a Snail). 
The shells of this genus are thin, shining, and 
depressed (except in Hfulva) ; the peristome is 
sharp and not reflected, and the aperture obliquely 
crescent-shaped. 
The animal of Helicella has an elongated ex¬ 
tremely compressed foot, which extends far 
behind; the upper tentacles are long, the lower 
ones short, all terminating in a knob. The 
lingual dentition is somewhat intermediate be¬ 
tween Vitrina and Helix, and resembles Limax in 
the long projecting single apex to the edge teeth; 
the teeth, however, are not so numerous (see 
fig. 19). The jaw is, like that of Limax, Vitrina , 
