HELIX. 



13T 



Helijc albolabris. 



of the mouth, abruptly and very widely re- 

 flected ; umbilicus of the mature shell covered 

 by the reflected peristome, which is continued 

 to the base of the shell. Greater diam. 36, 

 lesser 26 ; height 17 mill. 



Helix albolabris, Say, Nich. Encycl. pi. i, f. 

 1 (1817, 1818, 1819); .Journ. Acad. Nat. 

 Sci. Philad. II, 161 (1821) ; American 

 Conch. No. 2, pi. xiii, (1831); Bin.nev's 



ed. 21, pi. Ixix, f. 1.— Cuenu, Bibl. Conch. Ill, 21, pi. iii, f. 3, a.— 

 Adams in Thompson's Vermont, I, 158, with wood cut. — lilATox, 

 Zool. Text-Book, 193 (1826).— Ferussac, Tab. Syst. 36 ; Hist. pi. 

 xliii, f. 1, 2, 3. — BiNNEY, Bost. Journ. Nat. Hist. I, 475, pi. xiii 

 (1837) ; Terr. Moll. II, 99, pi. ii.— DeKay, N. Y. Moll. 26, pi. ii, f. 

 12 (1843).— Gould, Invert. 170, f. 101 (1841).— Leidy, T. M. I, 252, 

 pi. vi (1851), anat. — Pfeiffer, Symb. II, 22, excl. y and J; Mon. 

 Hel. Viv. I, 290, excl. fi and y ; in Chemnitz, ed. 2, I, 81, pi. xv, f. 

 7, 8 (1847), excl. var. C and D, pi. x, f. 4, 5. — Potiez et Michafd, 

 Gal. I, 69. — Reeve, Con. kon. no. 624. — Deshayes in Fer. I, 137, 

 pi. xliii, f. 1, 2, 3, 5. — Billings, Canadian Nat. and Geol. 1857, II, 

 98, f. 2, 3.— Bland, Ann. N. Y. Lye. VI, 358 (1858).— W. G. Binney, 

 Terr. Moll. IV, 43.— Morse, Amer. Nat. I, 6, pi. i, f. 1-11 ; 96, f. 2 

 (1867). 



Helix nifa, DeKay? N. Y. Moll. 44, pi. iii, f. 30 (1843). 



Mesodon albolabris, Morse, Journ. Portl. Soc. I, 8, f. 7, pi. iii, f. 8 (1864). 

 — Tryon, Am. Journ. Conch. Ill, 39, 44, pi. vii, f. 5-7 (18G7). 



Canada to Arkansas, Georgia to Minne- Fig. 230. 



sota. Also in the postpleiocene of the 

 Mississippi Valley. 



Specimens of H. albolabris are some- 

 times found bcarinj^ a well-developed 

 parietal tooth. Such are very plenty in 

 the Alleghany Mountains in Pennsyl- 

 vania. One is here figured (Fig. 230). 



The saffron-colored jaw of ZT. albolabris 

 is arcuate, of uniform breadth 

 throughout ; ends blunt, smooth 

 on their anterior surface, the 

 balance of the jaw with stout 

 ribs, denticulating either margin. 



The lingual membrane has 123 

 rows of 44 — 1 — 44 teeth each; 

 centrals long, conical, with an acute ape.x ; laterals of same shape, 



Helix albolabrU, var. 

 Fir. 231. 



Jiiw of Helix albohbris. [Morse j 



