146 LIMNiEADiE. 



P. acuta, Draparnaud. 



Phjsa acuta, Drap. Moll. Ter. et Fluv. France, p. 55, pi. 3, f. 10, 11.— Brown, 

 HI. Conch. G. B. pi. 14, f. 58, 59 (copied from Drap.).— Brard, 

 Coq. Envir. Paris, p. 69, pi. 7, f. 5, 6.— Michaud, Comp. Drap. 

 Moll. France, pi. 16, f. 19, 20.— D'Orbig. Moll. Canar. p. 74. 

 — Desh. Lam. Anim. s. Vert. (ed. Desh.) vol. viii. p. 403. — 

 Mermet, Moll. Pyren. p. 70. 

 „ subopaca, Lam. Anim. s. Vert. (ed. Desh.) vol. viii. p. 401 (teste Michaud). 



A southern Continental species, figured by Broivn for the P. 

 fontinalis, var. acuta. 



P. alba, Turton. 



Physa alba, Turt. Zool. Journ. 1825, vol. ii. p. 363, pi. 13, f. 3; Manual Land 



and F. W. Shells, p. 128, f. 1 1. — Jeffreys, Trans. Linn. Soc. 



vol. xvi. p. 521.) 



„ contorta, Michaud, Bull. Linn. Soc. Bordeaux, 1829, vol. iii. p. 368 (from 



which Esp. Nouv. Coq. 1829, p. 9, pi. 1, f. 15, 16; Comp. 



Drap. Moll. France, p. 83, pi. 16, f. 21, 22). 



Diastropha „ Gray, Manual Land and F. \V. Shells, p. 16, f. 11 1, as spurious 



(no description). 

 Phjsa fontinalis, Brown, 111. Conch. G. B. p. 30, pi. 14, f. 56, 57. 



A native of Southern Europe and Northern Africa, introduced 

 by Turton as from the river Torvin, in Wales. 



PLANORBIS. Muller. 



Shell spiral, discoid, dextral, of many whorls ; aperture 

 elliptical or semi-lunar, margin entire. 



Animal with a stout, broad, probosciditbrm head, flanked 

 by two setaceous, or subulate tentacula, with eyes at their 

 inner bases. Foot short, obtuse behind. Tongue with 

 transverse rows of numerous quadrate uncinated teeth. 



This very natural genus, representatives of which dif- 

 fering but slightly from species still living, are found in 

 fresh-water strata of even the oolitic epoch, has preserved 

 its form with great constancy, nor do the members 



