106 LAND AND FRESH-WATER MOLLUSKS. 
and aculeate”’ (see fig. 19)—Morse. 'The horny 
jaw of the cellar snail is represented in fig. 18, 
p. 104. 
Species of the genus Helicella are preyed upon 
by thrushes, blackbirds, and starlings, which may 
be found perfect in the stomachs of these birds. 
HELICELLA ALLIARIA—(the Garlic Snail) (PI. 
VIL., fig. 59)—is a widely-diffused species, but 
not so abundant as the last, and readily distin- 
guished from it and the other species of the 
genus by the diffusion of a garlic odour, which 
may frequently guide the collector to its retreat. 
The emission of the peculiar odour is not always 
obvious, but may generally be excited by press- 
ing the animal with a stalk of grass; or on 
immersion in hot water, those that may have 
retained it, do not generally fail to emit in death 
the yellowish fluid, which appears to be the 
source of this alliaceous smell. 
It frequents the same habitats as the last, and 
attains a great elevation on mountains. 
Shell flattened, with the spire very. little 
raised ; colour pale amber or horn, transparent, 
very shining; around the umbilicus there is a 
little opacity; upper surface smooth, or but 
slightly wrinkled ; whorls three and a half to 
four; umbilicus moderately large, scarcely ex- 
posing the second whorl; aperture crescent- 
shaped, not very oblique, rather broader than 
