LAND SNAILS. 
163 
aperture is furnished with from four to six folds 
—two or three on the pillar, and two or three on 
the outer lip. It is easily distinguished from 
the other Vertigos with dextral shells, by its form, 
the strong strise, and in the number and position 
of the teeth. 
It is a rare species, occurring chiefly in the 
North ; it has a wide distribution, though rare, 
in Ireland; and has a limited range in Europe. 
It occurs among decaying leaves in glens, but 
more usually under stones on the banks of lakes, 
and at the roots of rushes. It is abundant in a 
fossil state in the Oopford deposits. 
Vertigo pusilla —[the Wry-necked Whorl 
Shell) (PI. X., fig. 102) 1 .—The shells of this and 
the following species are sinistral and spindle- 
shaped; that of V. pusilla possesses six or seven 
folds within the aperture, which is subquadrate. 
It lives on old walls and dry banks, under 
stones, among leaves in woods, and is diffused 
throughout England, but is local and rare ; it is 
very rare in Ireland, and has been found in only 
a few localities in the North-east and West. It 
is a North and Central European species. 
Vertigo angustior —(the Narrow Whorl Shell ) 
(PI. X., fig. 111).—The shell of this species 
differs from the last in its much smaller size, 
in being proportionately narrower, and in pos¬ 
sessing only four to six teeth. The aperture is 
M 2 
