HELIX. 423 



aperture greatly developed, so that the aperture is nearly closed by 

 the teeth and tlie stricture behind the lip ; the upper lip-tooth has 

 often two or three points, and the tooth on the inner lip extends 

 quite to the base of the shell, so as to unite with the extremity of 

 the lip. 



The middle one of the three lobes is smallest, and their outline 

 regularly arched, so as to resemble somewhat the ace of clubs. 



Helix albolabris. 



Fig. 101. 



Shell orbicular-conical, yellowish horn color ; whorls five or six, convex, marked 

 with the lines of growth, and minute revolving lines; Up white, broadly reflected; 

 umbilicus closed. 



Helix albolabris. Say, Nich. Encyc. pi. 1, fig. I (1817, 1818, 1810) ; J. A. N. S. ii. 161 

 (182.3); Amer. Conch. No. 2, pi. 1.3 (1831); Binney's ed. 21, pi. 69, fig. 1.— 

 Chexu, Bibl. Conch. 3, 21, pi. 3, fig. 3«. — Eato^, Zool. Text Book, 193 (1826). 



— Adams, in Thompson's Vermont, i. l.'iS, with woodcut. — Fkrussac, Tab. Syst. 

 36 ; Hist. pi. 43, figs. 1, 2, 3. — Binney, Bost. Journ. Nat. Hist. i. 475, pi. 13 (1837) ; 

 Terr. IVIolI. ii. 99, pi. 2. — De Kay, N. Y. Moll. 26, pL 2, fig. 12 (1843). — Gould, 

 Inv. 170, fig. 101 (1841). — Leidy, Terr. Moll. U. S. i. 252, \A. 6, anat. (1851).— 

 Pfeiffer, Symb. Ii. 22, excl. / andc^; Mon. Hel. Viv. i. 290, exel. ji and y ; in 

 Chemnitz, 2d ed. i. 81, pi. 15, figs. 7, 8 (1847), excl. var. C. and D. pi. 10, figs. 4, 5. 



— PoTiEZ et MiCHAUD, Gal. i. 69. — Reeve, Con. Icon. No. 624. — Deshayes, in 

 Feh. i. 137, pi. 43, figs. 1, 2, 3, 5. — Billings, Canadian Nat. and Geol. ii. 98, figs. 

 2. 3. — Bland, Ann. N. Y, Lye. vi. 358 (1858). —W. G. Binney, Terr. Moll, iv. 

 43. —Morse, Am. Nat. i. 6, pi. 1, figs. 1 - 11 ; p. 96, fig. 2 (1867). 



[Mix rnfa, I)e Kay? N. Y. MoU. 44, pi. 3, fig. 30 (1843). 



Mesodon albolabris, Morse, Jouru. Portl Soc. i. 8, fig. 7; pi. 3, fig. 8 (1864). — Tryon, 

 Am. Journ. Conch, iii. 39, 44, pi. 7, figs. 5-7 (1867). 



Shell orbicular, depressed-conical, thin, shining, of a yellowish- 

 brown or russet-color ; whorls five to six, 

 rounded, separated by a well-defined suture, 

 and forming a moderately elevated spire, reg- 

 ularly and distinctly wrinkled by the lines of 

 growth which are crossed by very numerous, 

 delicate, revolving hair lines, scarcely visil)le 

 without a magnifier ; aperture semi-elliptical, ^ aih^br,s. 



contracted by the lip, which is white, and very 



broadly reflected ; outer edge sharp, somewhat waved, and colored 

 orange on the back ; umbilicus covered by the extremity of the lip. 

 Diameter generally over one inch. 



The animal varies in color, sometimes being pure white, cream- 

 color, or grayish ; head brownish above ; tentacula dusky at tip ; 



