416 MOLLUSCA. 



Physa Draparnaud ; Planorbis Guettard, spire in same plane ; Ancylus GeofFroy, 

 river-limpet, visceral mass conical. 



Fam. 5. Chilinidae. Pulmonary aperture larger than in any other pulmonate. 

 Visceral commissure longer than usual. Chilina Gray, Chilian-snail. 



Tribe 2. STYLOMMATOPHORA. 



Two pairs of invaginable tentacles (except Athoracopliorus), the posterior being 

 oculiferous ; male and female openings united (except in Vaginuhis, Onchidium, 

 and Peronia) ; 110 osphradium. 



Fam. 1. Succineidae. Anterior tentacles reduced ; male and female openings 

 distinct, but contiguous. Succinea Draparnaud, amber-snail. 



The Athoracophoridae (Athoracqphorus Gould) are allied here. 



Fam. 2. Helicidae. Land-snails. Shell external, spire short ; genital organs 

 generally with a dart and multifid vesicles ; genital orifice under right tentacle. 

 Helix L. , over 1600 species; H. aspersa Miiller, hedge-snail; H. pomatia L., 

 Roman snail; Vitrinu, Drap., glass-snail; Bulimus Scopoli (1200 species); 

 HempTi/illia Binney and Bland. 



The Philomycidae (Philomycus), without shell, allied here. 



Fam. 3. Arionidae. Shell absent, or represented by calcareous granules in 

 mantle. Slug-like. Genital opening just below pulmonary. Arion Fer., land- 

 sole ; eggs of A. hortensis phosphoresce for 15 days after deposition. 



Fio. 332. Arion einpi I'irorum (regne animal). Al respiratory aperture. 



Fam. 4. Pupidae. Shell external, spire long ; male duct without multifid 

 vesicles. Pupa Lam., chrysalis shell ; Clausilia'Dia.ip.; Vertigo Miiller ; Zospeuin 

 Bourguignat ; Balea Prideaux ; Ferussacia Risso ; Caecilianella Fer. 



Fam. 5. Limacidae. Slugs. Shell small or absent, generally internal, may 

 be spiral ; tail often with mucous pore. Genital ducts without multilid vesicles ; 

 genital opening under right tentacle. Umax L., slug, mantle reduced, shell 

 internal, 51 species; Vltrina Drap., glass-snail (here or with Helix); Parma- 

 cella Cuvier ; Zonites Montf. ; Urocyclus Gray ; Orpiella Gould. 



Fam. 6. Testacellidae. Pharynx protractile ; jaw absent ; cervical region 

 elongated. Slug-like, or with visceral sac spirally coiled ; carnivorous. Glan- 

 dina Schumacher ; DaudebardmHaxtm.; TcstacclktCnv., slug-like, subterranean, 

 feeds on earthworms, S. Europe, Canaries, introduced into Britain. 



Fam. 7. Vaginulidae. Without shell ; male opening beneath the right 

 tentacle, female midway beneath the mantle ; respiratory and excretory orifices 

 at hind end. Vaginulus Fer.; Atopos Simroth. 



Fam. 8. Onchidiidae. Marine, without shell, mantle often warty, some- 

 times with eyes ; genital openings widely separate ; female opening posterior, 

 near anus ; anus and pulmonary opening as in Vayinulus. Onchidium 

 Buchanan ; Peronia Blainv. 



