82 PULMONIFERA.—~- AURICULADZ. 
them. There is an umbilicus behind the pillar ; 
the operculum is hard, horny externally, and marked 
with a single, depressed, spiral line. 
This Mollusk lives on vegetable matter, like the 
snails, and is found in damp places, on a chalky 
soil. It is not very generally distributed, but is 
said to be abundant on the warm chalk hills, 
covered with brushwood, at Caversham, near 
Reading, in Berkshire. It is common also in 
the Isle of Portland, where I have seen it numerous 
in April, crawling on the twigs of shrubs, with the 
operculum carried behind, in a curious manner. 
FAMILY AURICULADZ. 
The characters of this family are the following :— 
The animal has a lengthened foot, a lengthened 
ringed muzzle, two somewhat cylindrical tentacles, 
with eyes near their bases on the inner side. The 
body is spiral, placed on the centre of the foot, and 
invested with a thin mantle, with a thickened edge. 
There is an ample spiral shell, the pillar of which is 
plaited at all periods of its life. 
Mr. Gray observes of these Mollusca, which are 
feebly represented in Britain by some three or four 
small species comprised in three genera, that they 
appear, by their habit and character, to be exactly 
intermediate between the land and the fresh-water 
Univalve Mollusca. They have the sessile eyes 
of the Pond-snails, placed behind instead of 
in front of the tentacles, and the subcylindrical 
tentacles of the Land-snails; but the tentacles are 
not retractile under the skin of the neck. In the 
same manner, the Carychia and the Acmea are ter- 
restrial, living in damp moss; the Conovuli live in 
