84 BRITISH MOLLUSKS. 



Zonites radiatus, Leach (1831), Turt. Man. p. 102. 



Discus rotundatus, Fitzinger (1833), Syst. Yerz. p. 99. 



Huryompliala rotundata, Beck (1837), Ind. Moll. p. 9. 



Patula rotundata, Held (1837), Isis, p. 916. 



Zonites rotundatus, Gray (1840), Turt. Man. p. 165. pi. T. f. 44. 



Helix (Delomphalus) rotundatus, Moquin-Tandon (1855), Hist. Moll. vol. 



ii. p. 107. pi. x. f. 9 to 12. 

 Hah. Throughout Europe. Azores. (Under stones and rums.) 



This and the following species have shells composed of narrow 

 subtubular whorls convoluted round an axis which leaves a wide 

 umbilicus open to the interior of the apex. S. rotundata is com- 

 mon throughout the British Isles and in all parts of Europe, and it 

 is very closely represented in the United States by a species in 

 which the whorls are still more openly convoluted, _H~. persjoectiva, 

 Say. H. Gueriniana, Lowe, a Madeiran species, and H. engonata, 

 Shuttleworth, a native of TenerifFe, are also of the same typical 

 form, with the shell more angled at the periphery. The whorls of 

 H. rotundata are obtusely produced, not to say angled, at the peri- 

 phery, and they are ribbed throughout with conspicuously raised 

 striae. The spire is faintly tessellated with brown, but sometimes 

 colourless and translucid, in which state it has been mistaken for a 

 Zonites. 



23. Helix rupestris. Sock Helix. 



Shell ; very largely perspectively umbiHcated, depressly orbicular, 

 brown horny, spire convex, sutures impressed, 

 whorls four to five, rounded, smooth or minutely 

 striated ; aperture small, lunar-rounded, lip simple. 



Helix rupestris, Studer (1789), Faun. Helvet. in Coxe, Trav. 

 Switz. vol. iii. p. 430 (without characters). 



Helix rupestris, Draparnaud (1801), Tail. Moll. p. 71. 



Helix pusilla, Vallot (1801), Hxerc. d'Hist. p. 5. 



Helix mnbilicata, Montagu (1803) , Test. Brit. p. 434. pi. xiii. 

 f. 2. 



Helix saxatilis, Hartrnann (1821), Syst. Gast. p. 52. 



Helicella rupestris, Eisso (1826), Hist. Nat. Hwrop. Merid. vol. iv. p. 69. 



Zonites rupestris, Leach (1831), Turt. Man. p. 103. 



Turbo Myrmecidis, Scacchi (1833), Osserv. Zool. vol. i. p. 11. 



Pyramidula rupestris, Fitzinger (1833), Syst. T'erz. p. 95. 



HuryompTiala umhilicata, Beck (1837), Ind. Moll. p. 9. 



Patida rupestris, Held (1837, Isis, p. 916. 



