1 10 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 BULIMUS, as originally constructed by Bru- 

 guiere, 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 Linnaeus) Draparnaud has form- 

 ed the genus SUCCINEA. 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 aquae 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 VITRIXA. 



The fluviatile shells, included by Linnaeus in his genu& 

 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 LIMNEA, containing conical or turreted shells, 

 with the right lip joined to the left at the base, and folding 



