CLAUSILIA. 283 



3. C. biplica'ta"^j Montagu. 



Turbo bijplicahis, Mont. Test. Brit. p. 361, tab. ii. f. 5. C. hi/jpUcata, 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 irre- 

 gular : mantle minutely speckled with white : tentacles dirty 

 reddish-grey ; upj)er pair subcylindrical and finely shagreened, 

 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 G. 

 Rolpliii ; 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 haK 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, contracted below, where a narrow but 

 deep channel is formed ; outer margin compressed and nearly 

 straight ; teeth as in aU the foregoing species, but the inter- 

 lamellar 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 : hasal crest strong, nearly straight : 

 umhilicus broader than usual in this genus : clausilium nearly 

 oval, sHghtly 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. 



