a 
108 MONOGRAPH OF BRITISH LAND AND FRESHWATER MOLLUSCA. 
Sun-Genus Vitrea Fitzinger. 
Hyalinia crystallina (Miiller). 
1774 Helix crystallina Miiller, Verm. Hist., ii., p. 23, no. 223. 
1821 — eburnea Hartmann, Neue Alp., i., p. 234. 
1827 — witrea Brown, Edinb. Journ.,i., p. 12, pl. i, f. 12-14. 
1833 Vitrea crystallina Fitzinger, Syst. Verzeichn., p. 99. 
1837 Helicella crystallina Beck, Ind. Moll., p. 7. 
1837 Polita crystallina Held, Isis, p. 916. 
1840 Zonites crystallinus Gray, Turt. Man., p. 176, pl. iv., f. 42. 
1855 — (Aplostoma) erystallinus Moq.-Tand., Hist. Moll.,ii., p.89, pl. ix., ft. 26-29. 
1864 — _ eustilbus Bourguignat, Moll. Alg., i., p. 76, pl. iv., ff 11-16. 
1871 Hyalina (Euhyalina) erystallina Kobelt, Catal. Europ. Binnenconch., p. 5. 
1875 — erystallina Weinland, Weichth. Schwab. Alb., p. 37. 
1881 — cavanne Paulucci, Bull. Soe. Mal. Ital., p. 80, pl. 1, f. 3. 
1877 Hyalinia crystallina Westerlund, Faun. Eur. Moll. Extram., p. 26. 
ISTORY.— Hyalinia crystallina (crystal- 
linus, clear or like crystal) is the type 
of Fitzinger’s genus Vitrea, a group 
erected by him solely for H. crystallina, 
and which is characterized by its small, 
crystalline, and closely-coiled shell. 
Westerlund has divided Vitrea into 
four sections: Crystallus Lowe, and 
Anomphala, Hydatina, and Monadea 
Westerlund, the present species being 
regarded as the type of Crystallus. 
According to Mr. George W. Tryon, 
M. Mabille has described as new under 
the name of Hyalina secernenda, the 
figure of H/. crystallina in Alber’s Malac. 
Maderensis, but the illustrations in this 
work are often inaccurate, and do not 
afford reliable specific characters. 
ar ar eS) ‘he Algerian Z. eustilbus described 
& ee 2 . as differmg from //. crystallina by 
dé ¢€ée<e,  _) the rounder base, and the more rapid 
I 
eer ' increase of the whorls, does not seem 
Bew SEA E tee Pe222222€% to differ from typical British shells. 
The H. humulicola Mabille (Hist. Mal., 1870) described as narrowly 
perforate, with less convex whorls, a more convex base, and a rounded 
unlabiate aperture, would seem also to agree with the present species. 
H. crystallina was first noticed as British by Dr. Gray, who, in 1821, 
recorded the species in the “ Medical Repository.” 
This species is associated with the Marchioness Paulucci, the gifted 
authoress of many important and valuable works upon the shells of 
Italy, and who has devoted especial attention and study to the terrestrial 
conchological fauna of Sardinia and the province of Calabria. 
Diagnosis.—//. crystalline is distinguished from all its alles by the 
small size and greenish-white transparency of its shell, as also by the 
greater number and closer coiling of its whorls, which increase in size with 
remarkable slowness. 
