186 HELICIDJE. 



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 stria? ; aperture 

 with three plaits, the margin white and detached 

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



Turbo bidens. Montagu, p. 357. t. 11. f. 7. (not 



Clausilia rugosa. Drop. p. 73. t. 4. f. 19, 20.; Leach, Syn. 

 Moll. 87. Turbo nigricans. Maton and Racket, Linn. Trans. 

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

 set. 46.; Tnrt. Diet. 225. Odostomia nigricans. Flem. Ed. 

 Ency. vii. 70. Helix perversa. Mutter , Verm. 118. Bu- 

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

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

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

 217.; Forbes and Hanley, B.M. iv. 121. t. 129. f. 1,2. 

 Clausilia roscida; C. cruciata. Studer, Schw. Conch. _20. 

 Clausilia perversa. Flem. B. A. 271. Strombifbrmis per- 

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

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

 33, 34. 



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

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

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

 Studer}. 



