CLASSES, ORDERS, ETC. 79 



it) Animal emitting an alliaceous smell. Shell amber or horn- 

 coloured, thin, upper surface smooth and darker than the lower 

 surface, which is not so white as in the other species ; whorls five, 

 the last not so large in proportion as in H. cellaria ; spire more 

 raised than in H. cellaria; umbilicus moderately large, exposing 

 the second whorl ; mouth narrow, crescent-shaped. Diameter \ 

 inch. Walls, gardens, woods. Slightly more local than H. cellaria. 



H. alliariap 



(d) Shell convex above, less convex below and only very 

 slightly marked with white, darkish horn-coloured ; whorls five to 

 five and a half, the body-whorl occupying about one-half of the 

 shell ; spire slightly produced, umbilicus narrow, deep, not dis- 

 closing the penultimate whorl, mouth forming three-fourths of y. 

 circle. Diameter fths inch. Woods and fields. Local. 



H. helvetica. 



(e) Shell subpellucid, dull waxy-coloured above, paler below, 

 clouded with opaque white round the umbilicus ; whorls four to 

 five, marked with irregular placed striae, which are interrupted by 

 the sutures and not continued from whorl to whorl ; spire slightly 

 produced; mouth semilunar; umbilicus very large. Diameter 

 fths to T V ns inch- Under stones and amongst moss on hedge- 

 rows and old walls. Common. H. nitidula.^ 



(/) Shell whitish or light horn-coloured, glossy, thin, with 

 numerous transverse circular striae ; whorls four, the body-whorl 

 occupying nearly one-half of the shell ; spire not much raised ; 

 suture deep, narrow; mouth roundish, oblique; umbilicus narrow, 

 deep, disclosing all the internal spire. Diameter Yijth to Jth inch. 

 Under stones and decayed leaves in woods and fields. Somewhat 

 local. H. pura:* 



(g) Somewhat like H. pura but more glossy, regularly striated, 

 horn-colour ; whorls four to four and a-half with the striae extend- 

 ing from whorl to whorl and not interrupted by the sutures as in 

 H. nitidula ; spire much depressed ; mouth semilunar ; diameter 



53 v. viridula, greenish-white. 



54 v. helmii, pearl-white ; v. nitcns, much smaller, lighter coloured, las 

 whorl expanded. 



65 v. margaritacea, pearl-white, nearly transparent. 



