38 Mr. Alder's Catalogue of Land and Fresh-tioater Shells. 



From H. nitidula it differs in being smaller, and in its bright, glassy lustre and trans- 

 parency. 



The great peculiarity of this species, however, is the very strong odour which the ani- 

 mal never fails to emit when disturbed or irritated. 

 49. H. nitidula, Drap , Shep. in Linn. Trans, v. xiv, p. 160. 



Shell nearly flat, deep yellowish horn-colour, sub-pellucid, rather strongly wrinkled, 

 of a dull waxy appearance above, more shining below, except near the umbilicus, 

 around which it is of an opaque white ; whorls 4^ ; umbilicus large, exposing the second 

 whorl ; diameter 3 tenths of an inch. 

 Animal, dark lead-colour. 

 Under stones by hedge sides, &c. ; common. 



Differs from H. cellaria in being smaller, rather more convex above and more concave 

 beneath, of a duller lustre, darker colour, and more strongly wrinkled above ; the um- 

 bilicus is larger and the aperture set at a less oblique angle. The opaque white also is 

 not so much diffused over the base of the shell, but is confined to the margin of the 

 umbilicus. The animal is of a darker colour. 

 30. H. radiatula, mihi. 



Shell depressed, horn-coloured, rather shining, transparent, regularly striated ; with 

 3i or 4 whorls, flattened at their junction with the inner ones, over which the strise ap- 

 pear continuous and strongly marked, giving the shell a radiated appearance under a 

 magnifier, the outer whorl rather large in proportion to the rest; underside smooth 

 without any whiteness ; umbilicus moderately large ; diameter 1^ tenth of an inch. 

 Animal black. 



In wet moss ; not uncommon. 



This species may be distinguished from the young of the foreg^^ing, to which it bears 

 some resemblance, by the regular and more distinct strise, and particularly by the flat- 

 ness of the whorls at their junctions. The same characters also serve to divide it from 

 the young of the two following species. 



51. H. lucida, Drap. 



H. nitida. Lam. 

 H. tenuis, Dillw. 

 Shell depressed, rather convex, thin, brownish horn-colour, transparent, shining, finely 

 striated, whorls 4 J or 5 ; umbilicus large, exposing the second whorl ; aperture round- 

 ish ; diameter A of an inch. 



Animal, jet black, giving the shell a dark chocolate appearance when alive. 

 In moist ditches and marshy places ; rare. Heaton Dean. 



It differs from H. cellaria, alliaria, and nitidula, in being more convex, more regu- 

 larly striated, of a darker colour, and without any trace of opacity on the underside. 



52. H. excavata, Bean MSS. 



Shell sub-globular, depressed, shining, transparent, horn-coloured, regularly striated, 

 whorls 5^ or 6, rather rounded and closely set ; base much rounded ; umbilicus very 



