140 LIMNiEADiE. 



PHYSA. Draparnaud. 



Shell thin, spiral, ovate, oblong, subglobose, sinistral, 

 smooth, polished ; mouth with the base entire, the colu- 

 mella more or less contorted. 



Animal with two long subulate or setaceous tentacula ; 

 eyes at their inner bases. Foot lanceolate. 



The British species of this genus have been referred to 

 two genera, Physa and Aplexus. The animal of the former 

 has a dilated mantle with lobed edges ; that of the latter 

 has a simple mantle. We believe these to be specific, or 

 at best sectional distinctions ; they should at least be re- 

 garded as such until the characters of the animal in the 

 majority of exotic species have been carefully examined. 

 The genus Physopsis differs from Physa as Jchatina dif- 

 fers from Bulimus, having the base of the columella trun- 

 cated. It is South African : there are no European 

 species. Fossil Physa, closely resembling existing forms, 

 are common in the Purbeck strata in Dorsetshire. 



P. fontinalis, Linnseus. 

 Oval : spire very short and obtuse. 



PlateCXXII. fig. 8, 9. 



Bulla fontinalis, Linn. Syst. Nat. ed. 12, p. 1185. — Pitlt. Hutchins, Hist. 

 Dorset, p. 40.— Mont. Test. Brit. vol. i. p. 226; Suppl. p. 9b". 

 — Maton and Rack. Trans. Linn. Soc. vol. viii. p. 126. — 

 Rack. Dorset Catal. p. 43, pi. 21, f. 6. — Turt. Conch- 

 Diction, p. 26. — Dillw. Recent Shells, vol. i. p. 487. — 

 Wood, Index Testae, pi. 18, f. 37. 



Turbo adversus, Da Costa, Brit. Conch, p. 96, pi. 5, f. 6. 



Planorbis bulla, Muller, Verm. Hist. vol. ii. p. 167. 



Btilinus perla, Muller, Naturforsch. 1781, vol. xv. p. C, pi. 1. 



Physa fontinalis, Drap. Moll. Ter. et F]uv. France, p. 54, pi. 3, f. 8, 9. — 

 Fleming, Brit. Animals, p. 276. — Tort. Manual L. and 



