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. PHYSA fontinalis. 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. Linn. Trans, viii. 126. t. 4. f. 1. (not de- 

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

 nus perla. O. F. Miiller, Naturforscher, xv. 6. t. 1. 

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

 Brug. Ency. Meth. 306. Bulla fluviatilis. Turton, Conch. 

 Diet. 27. -Helix bulheoides. 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- 

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

 Trans, xvi. 379. ; 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. 

 Moq. Tand. Moll. F. ii. 451. t. 32. f. 913. 



Var. 1., spire longer ft. 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. 



The narrow non-striated part is implanted in the 

 flesh. 



teeth lanceolate ; strongly toothed on each side. See 

 Otto Goldfuss, 48. t. 6. f. in., and Weigman y Arch. 



Q 



