LAND SNAILS. bop 
margin of the aperture being expanded, reflected, 
and strengthened by a thick white external rib ; 
from which latter character it has received the 
name of P. marginata. Individuals living in 
moist and grassy places are light brown, and 
more or less glossy and transparent; those much 
exposed to the weather are often grey or whitish 
and opaque. This is equally the case with many 
other glossy shells. 
P. badia of Adams, a North American snail, 
is considered by some European authors to be 
identical with this species, and it, like its ally, 
is OVoviviparous. 
The species is common throughout Britain ; it 
is partial to dunes and sandy pastures, among 
grass and roots of Psamma arenaria, bordering 
the sea-coast, and among the rejectamenta of 
our tidal rivers ; inland it occurs on rocks, under 
stones, on walls, and among moss. 
Pura anatica—(the English Chrysalis Shell) . 
(Pl. IX., fig. 99)—This species was added to 
our molluscan fauna in 1822, by Mr. Bean, and 
was considered peculiar to England when de- 
scribed by Ferussac; hence its trivial name. It 
is found throughout the northern counties of 
England, the West of Scotland, and all Ireland ; 
it is by no means general, or, except in parti- 
cular spots, plentiful. 
Though a British species of a northern type, 
