416 MOLLUSC A. 



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

 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 A thoracophorus), the posterior being 

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

 and Peronia) ; no osphradium. 



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

 distinct, but contiguous. Succinea Draf>arnaud, amber-snail. 



The Athoracophoridae (Athoracophorus 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; Vitrina Drap., glass-snail; Bulimus Scopoli (1200 species); 

 HempMllia 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. 



FIG. 332. Arion empirico-rwm (regne animal). Al respiratory aperture. 



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

 vesicles. Pupa Lam. , chrysalis shell ; Clausilia Drap. ; Vertigo Miiller ; Zospeum 

 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 multifid vesicles ; 

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

 internal, 51 species; Vitrina 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 ; Daudebardia, Hartm. ; Testacella Cuv. , slug-like, subterranean, 

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



Fain. 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 Vaginulus. Onchidium 

 Buchanan ; Peronia Blainv, 



