CLAUSILIA. 



183 



Moll. Franc, ii. 348. t. 23. f. 2 9. Turbo bidens. Chemn. 

 C. ix. 119. f. 960. n. 1.; Penn. B. Z. 131. Turbo per- 

 versus, var. Pulteney, Dors. 46. Pupa bidens. Drap. 

 TabL 61. Clausilia derugata. Jeffreys, Linn. Trans, xvi. 

 354. Clausilia lucida. Menke, Syn. 129. Clausilia 

 ungulata. Beck. Odostomia laminata. Flem. E. Ency. 

 vii. 67. 



In beech woods, among decayed leaves, and on 

 the bark of trees, especially in a chalky soil. 



Animal pale fulvous; upper tentacles long, cla- 

 vate. (Sturm, Fauna, t. .) 



Shell half an inch long, of a glossy reddish horn- 

 colour and nearly smooth ; spire composed of twelve 

 raised volutions ; aperture roundish-oval with a white 

 thick margin attached at the upper part of the body 

 volution, with two laminar folds, one of them straight 

 and placed near the top of the aperture and almost 

 central, the other curved and in the middle of the 

 pillar lip, frequently crenate ; and deep within the 

 mouth are three or four permanent ridges which are 

 visible on the back at the outside when held before 

 a strong light. 



Varies greatly in size, ventricoseness, and colour, 

 being sometimes greenish white and transparent. 



Montagu (Test. Brit. 359.) considered the white 

 variety as a shell deprived of its brown epidermis, 

 but the periostracum is as distinct on the greenish 

 white shell as on the brown specimen; both the 

 shell and the periostracum are differently coloured, 

 or rather uncoloured in that variety, from the ab- 

 sence of the colouring matter. 



Dr. Turton, by an oversight, first describes the 

 operculum as emarginate, and then makes his third 



N 4 



