186 HELICID^E. 



Animal grey. 



Shell an inch long, of a greyish brown horn-colour, 

 tumid in the middle ; spire composed of ten or eleven 

 rather swollen volutions, which are marked with re- 

 gular raised longitudinal lines ; aperture roundish- 

 oval, sinuous at the upper and outer angle ; the 

 margin thick, white, detached all round, with four 

 or five plaits, two of which are much longer than the 

 rest. 



Like other species, it is sometimes found transpa- 

 rent and colourless. 



86. 4. Clausilia nigricans. Dark Close Shell. — 

 Shell slender, sub-opaque, black-brown, with 

 fine raised somewhat granular strife ; aperture 

 with three plaits, the margin white and detached 

 aU round, (t. 5. f. 58, 59. ; t. 12. f. 143.) 



Turbo bideiis. Montagu, p. 357. t. 11. f. 7. (not Linn.) — 

 Clausilia rugosa. L>7-ap. p. 73. t. 4. f. 19, 20.; Leach, Syn. 

 Moll. 87. — Turbo niixricans. Maton and Racket, Linn. Trans. 

 viii. 180.; Mont. T.B. Supp. 131.; Dillw. 375.; Pult. Dor- 

 set. 46.; Tnj-t. Diet. 225. — Odostomia nigricans. Flem. Ed. 

 Ency. vii. 70. — Helix perversa. Midler, Verm. 118. — Bu- 

 limus perversus. Brug. — Turbo perversus. Penn. Brit. 

 Zool. iv. t. 82. f. 116.; Pidteney, Dorset. 46., part. — Clausilia 

 nigricans. Jeffreys, Linn. Trans, xvi. 351.; Gray, Man. 

 217.; Forbes and Hanhy, B.M. iv. 121. t. 129. f! 1, 2.— 

 Clausilia roscida; C. cruciata. Studer, Schiv. Conch. 10. — 

 Clausilia perversa. Flem. B. A- 271. — Strombifonnis per- 

 versa, young. Da Costa, B. C. 187. — Clausilia rugosa, 

 and C. obtusa. C. Pfeiffer, D. Moll. i. 63. 65. t. 3. i. 30. 

 33, 34. 



Var 1., smaller, more slender (t. 5. f. 58.) : Clausilia parvnla. 

 Leach, MSS., B. M. ; lurton, Zool. Journ. ii. 556., Man. 

 ed. 1. 74. f. 58.; Jeffreys, Linn. Trans, xvl. 352. (not 

 Stnder). 



