76 GASTEROPODA. HELICID. 
Helix nitida, Drap. Hist. des Moll. 117. pl. 8. figs. 23-25. 
Animal cerulescente-nigricans, lateribus szepius cinereis. Ten- 
tacula czerulescente-grisea. 
Habitat in locis humidis sub lapidibus, passim. 
Shell pellucid, shining, whorls five, transversely striated 
finely, luteous horn-coloured on their right side, whitish on 
their left. Longitudinal diameter rarely exceeding half an inch. 
Shell, with its apex depressed. Epidermis, in very fine spe- 
cimens, elevated into very little, hard scales. Suture between 
the whorls distinct. 
This beautiful species inhabits wet fields, beneath stones, 
and is very common. 
5. ZONITES CRYSTALLINUS. 
Z. testa subviridescente-hyalina, nitida, anfractibus 43 trans- 
versim tenuissimé strigosis. 
Helix crystallma, Mill. Verm. Hist. 223; Drap. Hist. des 
Moll. 118. pl. 8. figs. 13, 14. 
Habitat in pratis humidis, frequens. 
Shell pale greenish, transparent, shining, with four whorls 
and a half, which are very finely striated transversely. 
Inhabits wet meadows: is not uncommon. 
Longitudinal diameter one-eighth of an inch. 
This species, which has been confounded by most of our col- 
lectors with the young of Z. lucidus, has lately been distin- 
guished from it by several conchologists, who have supplied me 
with specimens from several parts of Britain. It is very abun- 
dant around London; and is by no means uncommon amongst 
the rejectamenta of the Thames, between Eton and Battersea. 
Genus 30. CHILOTREMA. 
Testa depressa, eequilateralis. Umdbilicus centralis, apertus. 
Peritrema perfectum, reflexum, tenue. Tentacula superiora 
elongata: inferiora breviuscula, tenuia. 
Shell depressed, equilateral. Umbilicus central, open. Pe- 
ritreme perfect, reflected, slender. Upper tentacula elongate ; 
under tentacula rather short, and slender. 
