42 HELICIDiE. 



Shells, p. 58, f. 42. — Brown, Illust. Conch. G. B. p. 53, 

 pi. 18*. f. 7 — Drapar. Moll. Terr, et Fluv. France, p. 118, 

 pi. 8, f. 13 to 20. — C. Pfeif. Deutsch. Land und Siissw. 

 Moll. pt. 1, p. 46, pi. 2, f. 36. — Charpent. N. Denks. 

 Schweiz. Ges. Nat. vol. i. (1837), p. 13 (Hyalinia). — 

 Rossmassl. Iconog. Land und S'ussw. Moll. pt. 8, p. 37, 

 f. 531. — Morelet, Moll. Terr, et Fluv. Portugal, p. 55. — 

 Chemn. (ed. Kiist.) Conch. Cab. Helix, No. 555, pi. 88, 

 f. 27 to 30.— L. Pfeif. Monog. Helic. vol. i. p. 59. 



Helix ehurnea, Hartm. Neue Alpina, vol. i. p. 234. 



„ cristallina, Ferus. Prodrom. Moll. No. 223 (Helicella). — Miller, Ann. 

 Philos. new ser. vol. iii. (1822), p. 379. — Lam. (ed. Desh.) 

 vol. viii. p. 87. 

 „ vitrea, Brown, Edinb. Journ. Nat. and Geogr. Sc. vol. i. pi. 1, f. 12, 13, 

 14.— Isis, 1832, p. 11. 



Discus crystal! i?itis, Fitzing. Syst. Verz. Erzh. Weichth. p. 99. 



Polita crystallina. Held, Isis, 1837, p. 916. 



Helicella „ Beck, Index Moll. Mu3. Christ. Frid. p. 7. 



Zonites crystallinus, Gray, Manual L. and F. W. Shells, p. 176, pi. 4, f. 42. — 

 Macgil. Moll. Aberd. p. 92. 



Shell very small, orbicular, flattened, thin, of an uniform 

 pellucid white, with a slight tinge of green, polished, 

 smooth, or very slightly striated, not opaque beneath. 

 Spire scarcely raised, apex obtuse. Whorls five, defined, 

 yet scarcely convex, very narrow, enlarging very gra- 

 dually ; the last but inconsiderably broader than the 

 penult, and not shelving above, so that the circumference 

 is broadly rounded. Aperture nearly as high as it is 

 broad, obliquely crescent-shaped, not quite equal in width 

 to half the total diameter, produced beneath the basal 

 level. Peristome acute, simple, not reflected. Base convex, 

 umbilicus small, profound. Diameter not much exceeding 

 the eighth of an inch. 



The animal is white, with fine dark lines running along 

 the neck and tentacula. This pretty little snail is widely 

 distributed in all parts of Britain ; but owing to its minute- 

 ness is apt to be overlooked : it should be sought for in 

 damj) places, under stones and among moss. 



