CLAUSILIA. 279 



whorls, as well as with a few indistinct spiral striae, the 

 intersection of which gives the surface a slightly granular 

 appearance : periphery angular or ridged : epidermis rather 

 thin : whorls 12-13, compressed, regularly increasing in 

 size, the last being equal in bulk to about one-third of 

 the shell, but somewhat narrower than the two or three 

 preceding whorls ; the first whorl nipple-shaped and quite 

 smooth : spire tapering to an obtuse point : suture rather 

 oblique, slight but distinct : mouth almost funnel-shaped, 

 compressed on the outer side, and having an effuse base, 

 like the lip of a water-jug ; teeth or folds as follows : two 

 on the pillar, the upper one of which is prominent and 

 oblique and forms one of the sides of a channel at the outer 

 angle, and the lower one is smaller and more sunk or deeply 

 seated, being also oblique and sometimes bifurcate, and 

 between these are occasionally from one to three smaller 

 folds or ribs ; one strong but deep-seated and not very dis- 

 tinct crescent-shaped fold (or lunella) on the pillar lip ; one 

 still more sunken and very slight spiral fold near the last ; 

 and occasionally one or two teeth (like those in Pupa) within 

 the outer lip : the outer lip is thick, white, and reflected : basal 

 crest sharp and angular, transversely ridged : umbilicus much 

 contracted by the intortion of the mouth : clausilium oval- 

 oblong, regularly curved, slightly dilated above. L. -5. B. 1 . 



Var. 1. albida. Shell greenish-white, with a few white 

 transverse lines. 



Yar. 2. Everetti, Miller. Shell smaller. 



Var. 3. gracilior. Shell longer and more slender. 



Var. 4. tumidula. Shell smaller, shorter, and more 

 ventricose. 



Var. 5. dubia. Shell larger and more ventricose. C. 

 dubia, Drap. Hist. Moll. p. 70, pi. iv. f. 10. 



Var. 6. dextrorsa. Shell resembling a Pupa in shape : 

 spire dextral. 



HABITAT : On old walls and rocks, as well as under 

 stones and on the trunks of trees, throughout these isles, 

 from Zetland to Guernsey. Var. 1. Dinton Hall, Bucks 

 (Goodall). Var. 2. Bristol (Miller); Whalsey Skerries, 

 Zetland ; Giant's Causeway and Co. Tyrone (J. G. J.). 

 Var. 3. Battersea marshes (J. G. J.). This last variety 

 appears to be the C. rugulosaof Ziegler. Var. 4. Brockley 



2c 



