MONOGRAPH OF BRITISH LAND AND FRESHWATER MOLLUSGCA, 81 
Hyalinia pura (Alder). 
1822 Helix nitidosa Férussac, Tabl. Syst., p. 45 (nomen nudum), 
“ ’ 
1830 — pura Alder, Trans. Nat. Hist. Soc. Northumb., ete., vol. 1, p. 37 
1830 — nitidula 68 Jeffreys, Trans. Linn. Soe., vol. xvi., p. 340. 
1833 — nitidula var. a Jeffreys, Trans. Linn. Soc., vol. xvi., p. 511. 
1837 — Jlenticula Held, Isis, p. 304. 
1840 aldert Bean, MS. Gray’s Turton’s Manual, p. 171. 
1837 Polita nitidosa Held, Isis, p. 916. 
1837 Helicella nitidosa Beck, Ind. Moll., p. 6. 
1866 — pura Tate, Brit. Moll., p. 107, pl. 7, f. 55. 
1855 Zonites (Aplostoma) purus Moquin-Tandon, Hist. Moll., p. 87, pl. 9, ff. 22-25. 
1862 — purus Jeffreys, Brit. Conch., p. 164. 
1871 Hyalina (EKuhyalina) pura WKobelt, Catal. Eur. Binnenconch., p. 5. 
1876 =— pura Weinland, Weichth. Schwab. Alb., p. 37. 
1877 Hyalinia pura Westerlund, Faun. Eur. Moll. Extram., p. 25.4 
1891 Vitrea (Polita) pura Smith, Journ. of Conch., vi., p. 339. 
ISTORY.—AHyalinia pura (pura, 
clear), though apparently first 
discriminated and named by Férussae, 
was not described by that author, but 
im 1830 it was clearly described and 
the name pura applied to it by Mr. 
Joshua Alder, of Newcastle-on-l'yne, 
one of the most distinguished naturalists 
of his time, and with whom the species 
is here associated in respectful homage 
to his exceptional abilities and acumen, 
According to Dr. Kobelt, it is the 
HH. pilatica of Bourguignat, from the 
slopes of Mount Pilatus near Hergyswy], 
Switzerland, and also //. clara ot Held. 
The Helix viridula of Menke, Helix 
électrina of Gould, Helix vitrina of 
Férussac, and Helix nitidula var. B of 
Draparnaud, have all been erroneously 
referred to H. pura by various authors. 
Diagnosis.—''his species resembles 
Hyalinia nitidula in form, but differs 
in its much smaller size, and different 
sculpture. From H. radiatula it may 
be readily separated by its less depressed shape, wider umbilicus, and by 
the absence of the strong and regular radiate grooving characterizing the 
upper surface of that species. From //. crystallina it is also readily 
distinguished by its larger size, greater convexity, duller aspect, less 
closely coiled whorls, wider umbilicus, and reticulate sculpture. 
When the shell contains the living animal, Hyalinia pura is strikingly 
distinguished by the opaque-white margin of the mantle from its ally 
H. radiatula, in which the pallial-edge is usually dark. 
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Original Description. —‘‘ 1. pura mihi. Shell depressed, rather shining, trans- 
parent, white, slightly striated or wrinkled; with four flattish whorls set diagon- 
ally ; under side more shining than the upper, and without any appearance of 
opacity ; umbilicus rather large; diameter rather less than ,% ths or about {th of 
an inch. 
30/3/08 F 
