178 LAND AND FRESH-WATER MOLLUSKS. 
The favourite abode of this minute species is 
among decaying leaves in woods, among herbage 
on mossy banks, and in moist places; it feeds on 
Marchantia. It is commonly distributed through¬ 
out Britain and Europe. In North America it 
is represented by the closely-allied 0. exiguum , 
Say. 
Though these very little snails are terrestrial, 
yet, as they are attracted to the vicinity of water, 
their minute shells occur, often abundantly, in 
the alluvia of rivers. This species is common 
as a fossil of the Newer Tertiaries. Among the 
freshwater shells of the Purbeck beds at Yillers- 
le-Lac, Doubs, there is a single species of land 
shell, Carychium Brotianum , the prototype of 
the genus. 
Genus Oonovulus. 
Conovulus denticulatus —(i the Toothed Gono - 
vulus) (Plate XI., fig. 134).—The shell is 
oblong, brittle, smooth, and of a brown or 
reddish-glossy colour; the spire is acute, with 
fine hairs around the sutures of the higher 
whorls ; the aperture is oblong, rather thickened 
with three or five plaits or folds on the pillar, 
and a few denticulations on the outer lip; the 
length is about three and a half-lines, the width 
one and a-half. The lingual ribbon comprises 
