PHYSA. 225 



membrane is such that I have failed in ascertaining 

 either the form of the central tooth, or the curve of 

 the horizontal row. 



101. 1. 'PnYSAfontinalis. Stream Bubble Shell. — 

 Shell horn-colour, oval, with a very short 

 obtuse spire ; aperture dilated at the base, 

 (t. 9. t. 11. f. 110.) 



Bulla fontinalis. Zmn. Trails, viii. 126. t. 4. f. 1. (not de- 

 scription) ; Li7m. S. N. 1185.; Mont. p. 226. — Buli- 

 nus perla. O. F. Miiller, Naturforsche?; xv. 6. t. 1. — 

 Planorbis bulla. Miiller, Verm. ii. 167. — Bulimus fontinalis. 

 Brug. Jilncij. Meth. 306. — Bulla fluviatilis, Turton, Conch. 

 Diet. 27. -Helix bullajoides. Donovan, B. S. t. 168. f. 2.??; 

 Linn. Trans, viii. p. 126. t. 4. f. 1. — Physa fontinalis. Drap. 

 Hist. p. 54. t. 3. f. 8, 9. ; Brard, p. 167. t. 7. f. 7, 8. ; La- 

 marck, vi. ii. 156. ; Leach, Syn. Moll. 100. ; Jeffreys, Linn. 

 Trans, xy'i. S79. ; Turton, Man. ed. 1. 127. f. 110.; Forbes 

 and Hanley, B. M. iv. 140. t. 122. f. 8, 9. — Limnea fonti- 

 nalis. Gray, in Sowerby, Gen. f. 8. — Turbo adversus. Da 

 Costa, B. C. 96. t. 5. f. 6. — Physa (Bulinus) fontinalis. 

 3Ioq. Tand. Moll. F. ii. 451. t. 32. f. 9—13. 



Var. 1., spire longer ("t. 11. f. 110*.); Forbes and Hanley, B. M. 

 iv. 140. t. 122. f. 10: Physa acuta? J. Sowerby (not 

 Drap.). 



Var. 2., last whorl rather angular behind: Physa alba. Jenyns, 

 MSS. (not Turton). 



In rivers and streams, on aquatic plants. 

 Animal blackish grey ; tentacles paler ; the jaw 

 triangular, lower edge arched, crenulated (fig. 55.) ; 



Fig. 55. 



The upper Jaws of Physa acuta magnified. 



^i^i^^ 



The narrow non-striated part is implanted in the 

 flesh. 



teeth lanceolate ; strongly toothed on each side. See 

 Otto Goldfuss, 48. t. 6. f. m., and Weigman, Areh. 



