HELIX. 



425 



Fig. 682. 



— Mrs. Gr.\t, Fig. of Moll. An. pi. 191, fig. 11, no dcscr. from Bost. Joiirn. — 

 Morse, Am. Nat. i. 99, figs. 6, 7 (18G7). — Not of Pfeiffer, Mou. llcl. Viv iii. 

 and iv. ; not of Chemnitz, ed. 2 (roemeri). 



Shell imperforate, flattened, convex on the upper surface, convex 

 below ; epidermis yellowish horn color, immacu- 

 late ; spire depressed ; whorls five, with delicate, 

 parallel oblique striae ; suture distinct, not deeply 

 impressed ; aperture contracted by the jjeristome, 

 flattened towards the plane of the base ; peristome 

 thickened, white, broadly and abruptly reflected ; 

 parietal wall Avith a prominent, white, tooth-like 

 process nearly parallel with the lower margin of 

 the aperture, not projecting towards the umbilicus ; 

 base convex. Greater diameter twenty-three, les- 

 ser eighteen, height ten millimetres. 



From Maine to Virginia and to Ohio. It prefers 

 mountainous country. 



Readily distinguished from the allied species by the very angular 

 and broad reflection of the peristome. 



H. clenlifera. 



Helix tliyroides. 



Fig. 108. 



Shell convex, yelloAvish horn color ; whorls five, delicately wrinkled ; aperture 

 rounded; lip Avhite, widely reflected; pillar with a single white tooth; umbilicus 

 partial. 



Helix thi/roidiis, Say, Nich. Encyc. (Amer. cd.) 1817, 1818, 1819; Journ. Acad. i. 123 

 (1817); Amer. Conch. (18.31) No. 2, pi. 13; cd. Binney, .33, pi. 13; cd. Ciienu, 

 Bibl. 3, 22, pi. 3, fig. 3. — E.\TOX, Zool. T. B. 193 (1826). — Ferussac, Hist.pl. 

 49 a, fig. 4 ; pi. 50 n, fig. 6 ? — Desiiayks, Encyc. Me'th. ii. 230 ( 1 830) ; in Lamarck, 

 An. sans "Vert. viii. 114; 3d ed. iii. 309; in Fer. i. 209. — Binney, Bost. Journ. 

 Nat. Hist. i. 488, pi. 18 (1837); Terr. Moll. ii. 129, pi. II. — Leidy, Terr. Moll. 

 U. S. i. 2.57, pi. 11, fig. 7-9 (18.51 ) anat. — De Kay, N. Y. Moll. 29, pi. 2, fig. 8.— 

 GoL'LD, Inv. 171, fig. 108 (1841). —Adams, Vermont Moll. 1.59 (1842). — Mrs. 

 Gray, Fig. Moll. An. pi. 291, fig. G, from Bost. Journ., no descr. 



Helix ihjiroidns, Pfeiffer, Mon. Hel. Viv. i. 345 ; in Chemnitz, 2d ed. i 331, pi. 58, 

 figs. 8, 9 (1850). —Reeve, Con. Icon. No. 677. — W. G. Binney, Ter. Moll. iv. 53. 

 — MoKSE, Am. Nat. i. 98, fig. 3 (1867). 



Anchistoma thi/roidi-'^, H. .nnd A. Adams, Gen. pi. 78, fig. 3, no descr. 



Mesodon thijroidcs, Tryon, Am. Journ. Conch, iii. 41, pi. 8, fig. 1 (1867). 



Shell rounded, convex, of a uniform yellowish-brown or russet 

 color ; whorls about five, convex, marked with delicate and parallel 

 lines of growth ; suture distinct; aperture broad, semi-lunar, con- 



