

CLAUSILIA. 



3. C. BIPLICA'TA*, Montagu. 



Turbo biplicatus, Mont. Test. Brit. p. 361, tab. ii. f. 5. C. biplicata, 

 F. & H. iv. p. 118, pi. cxxix. f. 4. 



BODY reddish-grey, dusky or almost black above and paler 

 on the sides and underneath; tubercles rather large, but 

 irregular : mantle minutely speckled with white : tentacles 

 dirty reddish-grey ; upper pair subcylindrical and finely sha- 

 greened, with slightly tumid bulbs ; lower pair conical : foot 

 long and rather narrow; tail depressed and bluntly rounded. 



SHELL subfusiform and slender, rather thin, but scarcely 

 semitransparent, having somewhat of a silky lustre, reddish- 

 or yellowish-brown, irregularly streaked with white lines, 

 which colour some of the striae and are often more conspi- 

 cuous near the suture, imparting a greyish hue to the shell, 

 strongly and closely striate in the line of growth, as in C. 

 Rolphii ; but the striae in the present species are straighter, 

 although slightly flexuous on the last whorl : periphery 

 obtusely angular: epidermis rather thick: whorls 12-13, 

 compressed, the last being very little more than one-fourth 

 of the shell and slightly narrower than the preceding 

 whorl ; the first whorl and a half are quite smooth and 

 glossy, and the second whorl is broader than the first : spire 

 slender and gradually tapering, obtuse at the point: suture 

 rather oblique, not very deep : mouth oval, angular, con- 

 tracted below, where a narrow but deep channel is formed ; 

 outer margin compressed and nearly straight ; teeth as in 

 all the foregoing species, but the interlamellar denticles on 

 the pillar seldom occur or are very slight : outer lip white, 

 expanded, prominent and detached, not so thick, as in the 

 last species : basal crest strong, nearly straight : umbilicus 

 broader than usual in this genus : clausilium nearly oval, 

 slightly curved, attenuated below. L. 0*65. B. 0'166. 



HABITAT : At the roots and in the bark of old willow- 

 trees ; Easton Grey, Wilts (Montagu) ; Clarendon, near 

 Salisbury (Bridgman) ; and banks of the Thames near 

 London, where this species is not uncommon. These 

 appear to be the only localities hitherto recorded or 

 known in this country. It has been found in a semi- 

 fossil state at Clacton and Grays in Essex. Its foreign 



* Having two folds. 



