BULIMUS. 151 



and reflected, forming an umbilicus behind the 

 pillar. 



The shell varies considerably in size and ventri- 

 coseness; also in colour, being sometimes whitish 

 horn colour, and semitransparent, arising, as in other 

 varieties of the kind, from a disordered state of the 

 animal preventing the secretion of the colouring and 

 chalky matter. 



It appears to grow slowly ; for Montagu observes 

 that scarcely one in ten of the shells he found had 

 their mouths perfected ; when young the shell, as in 

 the next, is short, conic, and trochus-like, with a 

 sub-quadrangular mouth. (T. B. 395.) 



65. 2. BULIMUS obscurus. Dusky Twist Shell. 

 Shell oval-oblong, brown, with the peristome 

 white and reflected, forming a small umbilicus, 

 (t. 6. f. 63.) 



Helix obscura. Mutter, Verm. 103.; Gmelin, S. N. 2661.; 

 Montagu, F. B. p. 391. t. 22. f. 5. Turbo rupium. Da 

 Costa, p. 90., from List. Ang. t. 2. f. 8. Bulimus hordea- 

 ceus. Brug. E. M. 334. ; Lam. Hist. viii. 236. Bulimus 

 obscurus. Drap. Moll. Franc, p. 74. t. 4. f. 23.; Brard, 

 p. 97. t. 3. f. 19. ; Turton, Man. ed. 1. 81. f. 63. ; Jeffreys, L. 

 T. xvi. 343. ; Rossm. Icon. vi. f. 387. ; Forbes and Hanley, 

 B. M. iv. 90. t. 128. f. 7. Lymnea obscura. Flem. Edinb. 

 Ency. vii. 78. Bulimus obscurus (3. Hartm. N.Alp. i. 222. 

 Merdigera obscura. Held. Isis, 1837, 917. Bulimulus 

 obscurus. Beck, Ind. 71. Helix stagnorum. Pulteney, 

 Dorset. 49 (?). Ena obscura. Leach, Moll. Syn. 81. 



In woods and old walls, under stones or moss. 



Animal rosy grey ; foot thick, paler ; upper ten- 

 tacles subulate. 



Shell half an inch long, and about a third as much 

 broad, brown or horn-colour, semitransparent ; spire 



L 4 



