FAMILY COLIMACEA. 



101 



Of the four, species of Clausilia inhabiting Britain, this is the 

 only one of which the shell is nearly smooth. Beneath the lens it 

 is abundantly striated in the same order in which the shell of the 

 other three species is plicately wrinkled, but to the naked eye the 

 surface is smooth and glossy, rufous brown, and sometimes of a 

 delicate pellucid straw-colour. The soft parts, as seen in our vi- 

 gnette of the living animal, are mottled with reddish-brown at the 

 side, the upper portion of the body being of a dingy yellowish-grey. 



Clausilia laminata does not appear in the Scottish lists of mol- 

 lusks, and it is a rarity in Ireland. In England it is of general 

 occurrence, but infrequent and local, increasing towards the south. 

 It ranges throughout the Continent from Sweden southwards, es- 

 pecially in the central parts. Some confusion has attended the 

 naming of the species in consequence of its having been taken for 

 the Linnean Turbo bidens, which is a Continental species, C. papil- 

 laris, Draparnaud, not found in Britain. 



2. Clausilia biplicata. Two-plaited Clausilia. 



Shell ; elongately fusiform, dingy olive-brown, marked at inter- 

 vals nest the sutures with short whitish 

 hair lines, whorls twelve, flatly convex, 

 densely ridge-wrinkled throughout ; aper- 

 ture pyriformly ovate, lip continuous, cal- 

 lously expanded, columella strongly two- 

 plaited, with two or more fine straggling 

 thread-plaits within. 



Helix perversa pars, Miiller (1774), Verm. Hist. 

 part 2. p. 118. 



Turbo liplicatus, Montagu (1803), Test. Brit. 

 p. 361. pi. xi. f. 5. 



Clausilia plicata, Gartner (1813), Syst. Wett. 

 p. 22 (not of Draparnaud). 



Odostomia biplicata, Fleming (1814), Edin. Encyc. vol. vii. part ii. p. 77. 



Clausilia biplicata and ventricosa, C.Pfeiffer (1821), Deutsch. Moll, parti, 

 p. 61 and 63. pi. iii. f. 27, 29. 



Clausilia Montagui, Gray (1825) „^ww. Phil. p. 413. 



Clausilia similis, Charpentier (1835), Rossm. Icon. vol. i. p. 77. f. 30. 



Clausilia vivipara, Held (1837), Isis, p. 309. 



