898 HELIX. 



FONTANA. 25. Shell compressed, obtusely keeled, 

 convex on both sides, with three whirls, and 

 the base umbilicated. 



Helix fontana. Lightfoot in Phil. Trans. Ixxvi. t. 2. f. l 

 to 4. Montagu Test. p. 462. t. 6. f. 6. Maton and 

 Racket, in Lin. Trans, viii. p. 193. Dorset Cat. p. 53. 

 t. 19. f. 19. 

 Inhabits ditches in England. Lightfoot, S^c. 

 Shell about two lines in diameter, of a glossy horn-colour, ex- 

 tremely flat, and nearly equally convex on both sides, but 

 depressed in the center ; the keel is formed by the gradual 

 slope of the outer whirl on both sides ; externally it much 

 resembles Nautilus lacustris, but is flatter, and not so con- 

 vex on the upper side, and may be at once distinguished by 

 its want of any internal partitions. 



RINGENS. 26. Shell imperforate, slightly keeled 

 and convex; aperture turned upwards, and 

 toothed on both sides. 



Helix ringeus. Linnsiis Syst. Nat. p. 1243. Muller Verm. 



ii, p. 17. Schroeter Einl. ii. p. 130. Born Mus. p. 369. 



t. 14. f. 11 and 12. Chemnitz, ix. part 1. p. 86. 1. 109- 



f. 919 and 920. Gmelin, p. 3618. Shaw Nat. Misc.x. 



t. 374. 

 Tormigeres ringens. De Montfort Conch, ii. p. S59. 



Leach Zool. Misc. ii. p. 128. 1. 107. 

 Grew Mus. 1. 11. f. 8. Bonanni Rec. 3. f.330 and 331, 



and Kirch, f.331 and 332. Lister Conch, t.99. f. 100. 



Argenville, t.28. f. 13 and 14. Martini Berl. Mag. ii. 



t. 4. f. 42. Famnne, t. 63. f. F 10. 

 Inhabits Brazil ; and is a land shell. Humphreys. 

 Shell about three-quarters of an inch long, and an iiich and 

 three quarters broad, of a whitish colour, mottled and dotted 

 with yellowish brown ; the aperture is turned up, and the 

 number of its teeth is said to vary from four to eight. It is 

 a very scarce shell, and was first described in an account of 

 the curiosities belonging to the Royal Society, by Dr. Grew, 

 who says, " both of the corners of the mouth are placed on 

 the circumference of the utmost round, whereby, contrary 

 to all other shells I ever yet saw, it hath the turban or whirle 

 made before. The assertion of Aristotle, that the turban 

 always stands behind, is here proved false." Its usual name 

 is the Grinner. 



