POLYGYRA. 171 
Helix (Tridopsis) tridonia, Beck, Index Moll. 1888, p. 22”. 
Helix (Polygyra) tamaulipasensis, Lea, Proc. Acad. Phil. 1857, p. 102°; Obs. Gen. Unio, xi. t. 24. 
fig. 113°’. 
Hab. Nortu America: Fort Gibson, Indian Territory 1°; Texas 1-8 17! 19, 
N.E. Mexico: State of Tamaulipas (Lieut. Couch ' 14). 
tHE. Mexico: Vera Cruz, only a dead shell (Uhde}°); Mexico, without nearer 
indication of locality (ége). 
Variable in size, like other species of the genus Polygyra. 
14. Polygyra behri. 
Helix (Polygyra) behrii, Gabb, Am. Journ. Conch. i. p. 208, t. 19. figg. 5-9 (good) (1865) '; 
Fisch. & Crosse, Miss. Scient. Mex., Mollusca, i. p. 276°. 
Heliz behriit (Gabb), Pfr. Monogr. Helic. Vivent. v. p. 424°. 
Dedalochila behrii (Gabb), Tryon, Am. Journ. Conch. iii. pp. 64, 80, t. 5 (10). figg. 40, 41, 43 
(1867) *. 
Hab. N.W. Mexico: Guaymas, State of Sonora (Gabb '~*). 
Aperture and umbilicus like those of P. tewasiana, but size larger, spire quite flat, 
and whorls less narrow. 
15. Polygyra ariadne. 
Helix ariadne, Pfr. in Zeitschr. fiir Malak. 1848, p. 120°; in Martini & Chemnitz, Syst. Conch.- 
Cab. ed. 2, Helix, i. p. 872. no. 3844, t. 65. figg. 29-31°; Monogr. Helic. Vivent. iii. 
p. 266°, and iv. p. 318°; Binney, Terr. air-breath. Moll. of N. Am. iv. p. 76, t. 78. figg. 1, 
3, 4°; Bland, Ann. Lyc. N. York, viii. pp. 24, 33 (1863) °; v. Mart. in Malak. Blatt. xii. 
p. 22 (1865); Binney & Bland, Land and Fresh-water Shells of N. Am.i.p. 104, fig. 180°. 
Anchistoma ariadne (Pfr.), H. & A. Adams, Gen. Moll. ii. p. 103°. 
Dedalochila ariadne (Pfr.), Tryon, Am. Journ. Conch. iii. pp. 66, 78, t. 5 (10). figg. 15, 16, 18 
(1867) *. | 
Helix (Polygyra) ariadne (Pfr.), Fisch. & Crosse, Miss. Scient. Mex., Mollusca, i. p. 287, t. 12. 
figg. 8, 8a-c”’. 
Polygyra ariadne (Pfr.), Binney, Terr. air-breath. Moll. of N. Am. v. (Bull. Mus. Comp. Zodl. 
Harv. Coll. iv.) p. 280, fig. 179; Manual of Am. Land-Shells, p. 376, fig. 411; Strebel, 
Beitr. Mex. Land- und Siissw.-Conch. iv. p. 50, t. 3. fig. 3". . 
Helix (Polygyra) couchiana, Lea, Proc. Acad. Phil. 1857, p. 102 *; Obs. Gen. Unio, xi. p. 139, 
t. 24. fig. 112”. 
Hab. Norta America: Texas 16, in the region of the Rio Grande ® 12, 
N.E. Mexico: Tamaulipas ?2 (Dr. Berlandier®"; Lieut. Couch®); Matamoros *". 
E. Mexico: only dead shells, on the shore of Vera Cruz (Uhde", Strebel M4), 
In this species the umbilical region is filled up by a part of the penultimate whorl, 
and is therefore only marked by an arcuate slit, with a very minute point-like hole. 
22" 
