882 TURBO. 



broad, thin, of a white or pale flesh-colour, with t\v%> or 

 more transverse yellowish lines becoming obsolete towards 

 the summit ; it has ten whirls, which are not well defined by 

 the sutures, and the aperture is narrow, and contracted at 

 the interior angle. 



DECUSSATUS. 159. Shell subulate, decussated with 

 longitudmal and very minute transverse striae ; 

 aperture sub-oval, and contracted at both 

 ends. 



Helix decussatus. Montagu Test. p. 399- t. 15. f. 7. Ma- 

 ton and Racket, in Lin. Trans, viii. p. 209- Dorset Cat. 

 p. 55. t. 19. f. 17. 

 Inhabits the coast of Dorsetshire. Montagu. 

 Shell three-tenths of an inch long, and one-third as broad, and 

 is white and slender ; Mr. Montagu says that in shape it is 

 similar to T. politus, " except in the aperture which stands 

 rather more oblique, the outer lip more expanded in the 

 middle, and contracted at the lower angle." 



w w ^ ^ vr ^ 



Depressed. 



NAUTILEUS. 160. Shell flattish, with the whirls 

 annulated and crested on the back. 



Turbo Nautileus. Linnaus Si/st. Nat. p. 1241. Schroeter 



Fluss. p. 238, and Einl. ii. p. 60. Chemnitz, ix. part 2. 



p. 63. t. 123. f. 1077. GmeHn, p. 3612. Shaw Nat. 



Misc. xxii. t. 964. Maton and Racket, in Lin. Trans. 



viii. p. 169. t.5. f. 4. Dorset Cat. p. 50. t. 19- f. I6. 

 Nautilus crista. Linnaus S^st. Nat. (edit. 10.) p. 709- 

 Planorbis imbricatus. Mutter Ferm.ii. p. 165. 

 Helix Nautileus. Montagu Test. p. 464. t. 25. f. 5. 

 Helix carinata. Adams's Microscope, p. 635. t. 14. f. 10. 

 Helix spinosa. Adams's Microscope, p. 636. t. 14. f. 11, 



and t. 22. f. 39- 

 Le Planorbe tuille. Geoffroy, p. 97. t. 3. 

 Walker's Minute Shells, f. 20 and 2 1 . 

 Inhabits fresh water, on aquatic plants. Germany and Switz- 

 erland. LinncEus. France. Geojffroy. Denmark. Muller. 

 England. Walker, Sfc. 

 Shell about half an inch in diameter, of a pale transparent horn- 

 colour, and covered with a brown epidermis ; it is furnished 

 with distant annulations, or elevated transverse ribs, which 



