110 MOLLUSCA. 
projection of the last turn but one of the spire. The ani- 
mal is furnished with four tentacula, with eyes at the tips 
of the two longest. The H. pomatia is the type of the 
genus. 
The genus Butimts, as originally constructed by Bru- 
guiére, was faulty in the extreme, but Lamark has new 
modelled it so as to include those land shells which are tur- 
reted or conical, with the mouth larger than broad, and hav- 
ing, in general, the margin reflected with age. Like the 
Helices, they have no operculum, and possess four subu- 
lated tentacula. 
From the Helix succinea of Miiller (the putris of Mon- 
tagu and Donovan, not of Linnzeus) Draparnaud has form- 
ed the genus SuccrnEA. The mouth is large in propor- 
tion to the size of the shell, and effuse at the base with the 
outer lip thin, and the pillar attenuated. The H. succinea, 
although found in damp places, .is not amphibious. It 
never enters the water voluntarily. Indeed, Miiller says, 
“ Sponte in aquam descendere nunquam vidi, a contra quo- 
ties eum aque immisi, confestim egrediebatur.” The same 
remark is made by Montagu, and we have often witnessed 
its truth. 
The Helix pellucida of Miiller has been formed into a 
new genus by Daudebard, which he termed Helico-limax, 
but which Draparnaud, to avoid the use of a hybrid name, 
changed for the term Virrina. 
The fluviatile shells, included by Linnzus in his genus 
Helix, may, for the sake of present convenience, be con- 
sidered as forming two sections, viz. those with and those 
without an operculum. To the former belongs the very 
natural genus LimnrA, containing conical or turreted sheils, 
with the right lip joined to the left at the base, and folding 
