FAMILY LYMNjEACEA. 



151 



spiration, but I have not succeeded in confirming this observation, 

 and have great doubts of its accuracy. 



One or two species of Physa of the ordinary P. fontinalis type 

 have been collected in Syria, China, Singapore, and the Philip- 

 pine and Sandwich Islands, and a single curiously turriculate 

 species with a delicate transparent glassy shell has been lately dis- 

 covered in Egypt, and at Benguela, south of the Congo River. At 

 Natal, in the same range of habitation, another singularly opposite 

 form of Physa occurs, short and globose, with the spire not at all 

 exserted, having the columella truncated at the end (Physopsis) ; 

 and a second species of this form has been lately collected at Port 

 Essington, North Australia. 



The British Physa are : — 



1. fontinalis. Shell sinistral, ovate, transparent, of four smooth 



whorls, the last of which is ventricosely inflated. 



2. hypnorum. Shell sinistral, fusiformly oblong, transparent, of 



five smooth whorls, convoluted attenuately. 



1. Physa fontinalis. Stream Physa. 



Shell ; sinistral, ovate, mostly subglobose, yellowish horny, very 



thin and transparent, almost glassy, 



spire short, rather obtuse, sometimes 



produced, whorls four, convex, smooth, 



moderately shining, faintly irregularly 



striated in the direction of the lines 



of growth, opakely margined at the 



sutures, last whorl inflated ; aperture 



pyriformly ovate, columella slightly 



callously twisted. 

 Bulla fontinalis, Linnaeus (1758), Syst. Nat. 10th edit. p. 727. 

 Planorbis bulla, Miiller (1774), Verm. Hist, part ii. p. 167. 

 Turbo adversus, Da Costa (1778), Test. Brit. p. 96. pi. v. f. 6. 

 Bulimus perla, Miiller (1781), Naturf vol. xv. p. 6. pi. i. 

 Bulimus fontinalis, Bruguiere (1789), JEnc. Meth. Vers, vol. 

 Physa fontinalis, Draparnaud (1801), Tall. Moll. p. 52. 

 Helix bullaoides, Donovan (1803), Brit. Shells, vol. v. pi. clxviii. f. 2. 

 Bulla fluviatilis, Turton (1819), Conch. Diet. p. 27. 

 Limnea fontinalis, Sowerby (1823) , Gen. Limn. f. 8. 

 Bulimus fontinalis, Beck (1837), Ind. Moll. p. 117. 



p. 308. 



