162 MOLLUSCA. 
Helix (Arionta) mormonum (Pfr.), Fisch. & Crosse, Miss. Scient. Mex., Mollusca, i. p. 251°. 
Aglaia mormonum (Pfr.), Tryon, in Am. Journ. Conch. ii. p. 314, t. 22 (5). fig. 14°. 
Arionta mormonum (Pfr.), Binney, Terr. air-breath. Moll. N. Am. v. (Bull. Mus. Comp. Zodl. 
Harv. Coll. iv.) p. 866, fig. 2487; Manual of Am. Land-Shells, p. 140, fig. 120°. 
Hab. Nortu America: Mormon Island, California!~+; California®, San Joaquin 
Valley, north to Mt. Shasta47; Fresno County to Klamath Lake’ ®; between 
the Sierra Nevada and the Coast Range ®. 
This species has been erroneously ascribed to Mexico, by confounding Sonora in 
Tuolumne county, California, with the State of Sonora in Mexico ®. 
Helix stolephora. 
Helix (Helicella) buphthalmus, Férussac, Tabl. Syst. Moll. p. 42. no. 238°. 
Helix stolephora, Valenciennes, in Humboldt & Bonpland’s Obs. Zool. ii. p. 242, t. 56. figg. 4a, 6’; 
Pfr. Monogr. Helic. Vivent. i. p.52°; in Martini & Chemnitz, Syst. Conch.-Cab. ed. 2, 
Helix, i. p. 196, t. 82. figg. 1, 2°. 
Hab. New Spain !~4, 
A well-known species of Nanina, ascribed wrongly to Mexico by Valenciennes 2. 
Beck, Ind. Moll. 1838, p. 46, states correctly that it belongs to the Philippines. 
POLYGYRA. 
Polygyra, Say, in Journ. Acad. Phil. 1. 2, p. 277 (1817); v. Martens, in Albers’s Die Helic. ed. 2, 
p- 95; Pilsbry, Proc. Acad. Phil. 1889, p. 193, and 1891, p. 313. 
Dedalochila and Polygyra, Beck, Index Moll. p. 21 (1838). 
Aperture of the shell straightened by a conspicuous shelly prominence on the wall 
cf the penultimate whorl (parietal fold), and by one or more thickenings (teeth) on 
the external and basal margin; immediately behind the aperture the last whorl is 
distinctly constricted in its lower part. Whorls narrow, gradually increasing, rather 
numerous (93 or more). Coloration uniform, brownish, in worn specimens white. 
Sculpture consisting of prominent rib-like striae, which are parallel to the aperture, 
more distinct on the upper side, and generally increasing in strength near the aperture. 
Umbilicus present, in some species widely open, in others more or less filled up by the 
prominent lower part of the penultimate whorl, which conceals all others (umbilicus 
obstructus), Average size 8-12 millim. in diameter. Shell generally depressed. 
Jaw with stout vertical ribs. Genital organs very simple, without dart-sac, flagellum, 
or other appendages. [See Binney, Notes on Am. Land-Shells, ii. 2, p. 28, t. 5. fige. 3 
and 6, P. troostiana (1874). ] 
The head-quarters of this genus are the Southern States of North America and the 
northern parts of Mexico; the northernmost locality known hitherto is Kentucky R., 
opposite Cincinnati (P. dorfeuilleana, Lea). Southwards it does not reach the continent 
