HELICIDJE. 183 



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.) 



60. 2. BULIMUS obscurus. Dusky Twist Shell. 



(t. 6. f. 63.) Shell oval-oblong, brown, with 



the peristome white and reflected, forming a 



small umbilicus. 



Helix obscura. Mutter, Verm. 103.; Montagu, 



p. 391. t. 22. f. 5. 

 Turbo rupium. Da Costa, p. 90. ; List. Any. 



t. 2. f. 8. 

 Bulimus hordeaceus. Brug. E. M. 334. ; Lam. 



obscurus. Drap. 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. 

 Ena obscura. Leach, Mollusc, p. 113. 

 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 

 composed of six or seven raised volutions, slightly 

 striate longitudinally; aperture oblong-oval, with the 

 margin white and reflected, forming a slight um- 

 bilicus behind the pillar. The young shell conical, 

 pyramidical, with a subquadrangular mouth. 



Except in size, it is not easy to form a very dis- 

 tinctive character between this and the last species ; 

 but this is of a paler brown, with the volutions more 

 rounded, and the peristome is white. 



