412 helicidj:. 



Shell discoidal, globose, or conoid, aperture transverse, oblique, 

 lunate, or rounded, margins distinct. 



Jaw arcuate, vertically ribbed, margins crenulated. 



Lingual membrane broad, teeth numerous, centrals tricuspid, lat- 

 erals l»icuspid, uncini denticulated or serrated, centrals and laterals 

 sometimes simply conical with an acute tip. 



Helix alternata. 



Fig. 114. 



Shell orbicular, depressed, fawn colored, barred with ol^llque, zigzag lines of 

 dusky; whorls five or six. with prouiiueut wrinkles at the lines of growth ; lip 

 simple ; umbilicus large and deep. 



Helix alternate, Say, Nieh. Encyc. iv. pi. 1, fig. 2, 1817, 1818, 1819 ; Joiini. Acad. ii. 161, 

 1821 ; Binney's cd. 6, 21, pi. 69, fig. 2. — Eaton, Zool. Text Book, 193 (1826).— 

 BiNNEY, Bost. Jouni. Nat. Hist. iii. 428, pi. 25 (1840) ; Terr. Moll. ii. 212, pi. 24. 



— Gould, Inv. 177, fig. 114 (1841). — Leidy, Terr. Moll. U. S. i. 2.53, pi. 7, figs. 

 2-5 (1851), anat. — De Kay, N. Y. Moll. 29, pi. 2, fig. 9 (1843). —Adams, Ver- 

 mont Moll. 162, figure (1842). — Ferussac, Tab. Syst 44; Hist. pi. 79, figs. 8, 9, 

 10. — Potiez and Michaud, Galerie, 104. — Chemnitz, i. 2d ed. 181, t. 24, figs. 17, 

 18. — Pfeiffer, Mon. Hel. Viv. i. 102. — Deshayes, in Fer. Hist. i. 89. — Reeve, 

 Con. Icon. 670 (1852). —Billings, Canad. Nat. ii. 99, figs. 4, 5 (1857). — W. G. 

 Binney, Terr. Moll. iv. 98. — Bland, Ann. N. Y. Lye. vii. — Morse, Am. Nat. 

 i. 187, figs. 17, 18 (1867). 



Angulspira alteriHita, Morse, Journ. Portl. Soc. i. 11, fig. 15 ; pi. 4, fig. 16 (1864). — Try- 

 on, Am. Journ. Conch, ii. 261, pi. 4, fig. 47 (1866). 



Helix scabra, Lamarck, An. sans Vert. vi. part 2, 88. — Deshayes, Encyc. Mc'th. ii. 

 219 (18.30) ; in Lam. viii. 66; 3d cd. iii. 292. — Ciienu, 111. pi. 6, fig. 11. 



Helix Irifecta, Parreys MS. — Pfeiffer, Mai. Bl. 1857, 86 ; Mon. Ilel. Viv. iv. 91, non 

 Reeve. 



Helix stromv/hdes, Vffavfer, Proc. Zool. Soc. 1854, .53 ; Mon. Hel. Viv. iv. 91. — Reeve, 

 Con. Icon. 1296 (1854). — Vide W. G. Binney, Terr. Moll. iv. pi. 77, fig. 8. 



Helix mordax, Shuttleworth, Bern. Mitt. 1852, 195. — Gould, in Terr. Moll. iii. 19. 



— W. G. Binney, Terr. Moll. iv. 99. — Pfeiffer, Mon. Hel. Viv. iii. 635.— 

 Bland, Ann. N. Y. Lye. vii. (and var. feir/nsoni). 



Helix diibia, Sheppard, Tr. Lit. Hist. Soc. Quebec, i. 194. — McCulloch, (where?) 

 teste Binney, Terr. Moll. i. 192. 



Shell orbicular, depressed, slightly convex above and below ; gen- 

 eral tint a light fawn color, which, on the upper surface, alternates 

 in about equal proportions, with oblique, zigzag bars of dark-brown ; 

 these bars grow narrower and lighter on the lower surface as they 

 converge to the umbilicus ; they are generally interrupted l)y a light 

 colored zone which issues from the middle of the inner margin of 

 the aperture ; whorls five to six, flattened above, coiis))icuously 

 plaited at the lines of growth so as to produce a rough surface 



