Mr. Alder's Catalogue of Land and Fresh-water Shells. 37 



46. H. pura, mihi. 



Shell depressed, rather shining, transparent, white, slightly striated or wrinkled ; with 

 4 flattish whorls set diagonally ; under side more shining than the upper, and without 

 any appearance of opacity ; umbilicus rather large ; diameter less than 2 tenths or about 

 1 sixth of an inch. 



Animal white, with 2 black lines like the preceding ; cloak white, speckled with black. 

 A variety has the shell of a pale horn-colour, and the animal rather darker. 

 Uhder stones, decayed leaves, &c., in woods ; not unfrequent. 



This species somewhat resembles the preceding, but is readily distinguished from it 

 by being larger, more convex, and less shining ; the whorls less closely set, and the out- 

 er one larger in proportion to the rest. The umbilicus also is much larger. It has 

 sometimes been taken for a variety of H. nitidula, but differs from that species in being 

 scarcel)^ one third the size, of a different colour, and without any trace of opacity un- 

 derneath. 



White varieties of this tribe of shells undoubtedly sometimes occur, but these are ge- 

 nerally mere sports of nature, which, like similar varieties in the higher classes of animals 

 are not perpetuated without the aid of art or domestication ; such is not the case with 

 this species, which preserves its characters unchanged even when living in the midst of 

 its congenors. 

 4)7. H. cellaria. Mull., Lam. 

 H. nitida, Drap. 

 Shell flat, pale yellowish horn-colour, transparent, shining, very slightly wrinkled ; 

 with 5 or 5i whorls ; the under side clouded with opaque white ; umbilicus moderately 

 large, scarcely exposing the second whorl ; diameter 4 tenths of an inch. 

 Animal pale grey, white when young. 



In cellars and yards, and also under stones in fields and woods ; common. 

 This is the only species which is found in the habitations of man in the centre of 

 large towns. 

 48. H. alliaria, Miller, in Ann. Phil, new series, v. iii. p. 379. 

 H. foetida, Stark, in Elem. Nat. Hist. v. ii. p. 59. 

 H. nitida, Shep. in Linn. Trans, v. xiv. p. 160 ? 

 Shell nearly flat, slightly globular, thin, transparent, horn-coloured, very shining, 

 nearly smooth; whorls 4; underside sometimes slightly tinged with opaque white; 

 umbilicus rather large ; diameter i of an inch. 

 Variety of a transparent greenish white. 

 Animal black, emitting a strong smell of garlick. 

 Under stones, decayed leaves, and moss, in woods ; common. 



It differs from H. cellaria in being not above one-third the size, and more convex, in 

 having the aperture less oblique, the umbilicus larger, and the white on the under side 

 not so well defined. 



