94 
LAND AND FRESH-WATER MOLLUSKS. 
being worms and small beetles; yet, on the 
other hand, the larvae and imago of many beetles 
are the aggressors and not the victims. Snails 
also furnish food to the thrush, blackbird, star¬ 
ling, &c., the smaller species being swallowed 
entire; of the larger kinds the shell is broken 
on a stone, and the snail extracted. The do¬ 
mestic fowl will also feed upon them. 
The respiratory orifice is seen on the right 
side, beneath the margin of the shell, when the 
snail is in motion. The reproductive orifice , as 
in the slugs, is situated near the base of the 
right upper tentacle. The eggs of most of the 
Helicidce are globular in shape, and transparent 
or opaque; some are enveloped in a hard cal¬ 
careous shell. They are usually laid in the 
summer, and vary in number from ten to one 
hundred, according to the species, either isolated 
or united together into a mass. The young 
appear at the end of about fifteen to twenty 
days, and attain about a third of their full size 
before hybernating, and usually complete their 
shell on their attaining their first year. The 
Helices do not live to a venerable age, for the 
majority of the species apparently do not sur¬ 
vive the second winter. 
Mr. E. J. Lowe communicated to the Eoyal 
Society, in 1854, observations he made on the 
growth of shells of land snails. The facts arrived 
