CLAUSILIA. 
187 
Yar. 2., shorter, fewer whorls : Clausliia Everettii. Miller^ 
Ann. Phil..f n. s., xix. 377. 1822. 
Yar. 3., larger, more ventricose (t. 12. f. 143.) : Clausilia dubia. 
Drap. Hist 70. t. 4. f. 10. ; Alder., Cat. Supp. 3., Mag. ZooL 
and Bat. ii. 111. ; Gray., Man, 216. t. 12. f. 143. — Clausilia 
crassula. Potiez and Mich. Cat. i. 180. t. 18. f. 8 — 10.? 
— Clausilia rugosa, Var. Alder., Cat. 32. ; Forhes and Hanley., 
Brit. Moll. 121.- — Clausilia similis. Gilbertson., MSS. B. 
M. (not Fer.). 
Common under stones and in old walls. 
Animal brown, corrugated, foot narrow. 
Shell about half an inch long, glossy black or 
grey, often marked with short cinereous streaks, with 
regular raised lines, which, when closely examined, 
appear a little granular; spire composed of from 
seven to ten rather raised volutions ; aperture oval, 
with the inner lip a little contracted, with three plaits, 
all on the pillar, the lower one interior and hardly 
distinguishable in the full-grown shell ; the margin 
thick and white, but not reflected, detached all 
round. 
This very common species varies greatly in size, 
in the slenderness and ventricoseness of the shell, and 
in the strength or slightness of the concentric striaB ; 
but in a large series all these varieties gradually and 
uninterruptedly pass into one another, and they may 
all be found in specimens collected from the same 
locality. It is also rarely found transparent and 
colourless. Mr. J effreys describes a distorted spe- 
cimen, with a prominent medial ridge down the 
whorls. 
Mr. Alder has kindly communicated to me a 
specimen of the shell he sent to Dr. Turton, which 
