POLYGYRA. 169 
12. Polygyra ventrosula. (Tab. VII. figg. 10, 10 a-c, 11.) 
Heliz ventrosula, Pfr. P. Z. S. 1845, p- 131°; in Martini & Chemnitz, Syst. Conch.-Cab. ed. 2, 
Helix, i. p. 373. no. 385, t. 65. figg. 5, 6°; Monogr. Helic. Vivent. i. p. 417°; Reeve, 
Conch. Icon. vii., Helix, t. 118. fig. 687 (good) ‘; Binney, Terr. air-breath. Moll of N. Am. 
iv. p. 72, t. 77. fig. 14°; Bland, Ann. Lyc. N. York, vii. p. 444 (1861) °, and viii. pp. 24, 
32 (1863) "; Binney & Bland, Land and Fresh-water Shells of N. Am. i. p- 92. figg. 164 
(shell), 165 (jaw), 166 (radula) °; Tryon, Proc. Acad. Phil. 1863, p. 281°. 
Dedalochila ventrosula (Pfr.), Tryon, Am. Journ. Conch. iii. pp. 63, 80, t. 5 (10). fig. 39 (bad) 
(1867) **. 
Helix (Polygyra) ventrosula (Pfr.), Fisch. & Crosse, Miss. Scient. Mex., Mollusca, i. p. 274". 
Polygyra ventrosula (Pfr.), Binney, Terr. air-breath. Moll. of N. Am. v. (Bull. Mus. Comp. Zodl. 
Harv. Coll. iv.), p. 269. figg. 166, 167, and p. 263. fig. 157°; Manual of Am. Land-Shells 
(Bull. U. S. Nat. Mus. no. 28), p. 367. figg. 400, 401, and p. 360. fig. 391. 
Hab. Nort America: Texas 15 8 10-18, 
N.W. Mexico: Tres Marias Is. (Forrer); near Mazatlan (Rémond®11); Sierra 
Madre *; Colima, in the Sierra Madre, State of Jalisco (Xantus 1°); Tepic, State 
of Jalisco (fichardson); Mexico, without nearer indication of locality > 8 11 1218 
(Hinds \-4), 
Var. hindsi : minor. 
Helix hindsi, Pfr. P.Z.S. 1845, p. 182; in Martini & Chemnitz, loc. cit., Helix, i. p. 373. 
no. 386, t. 65. figg. 7, 8'°; Monogr. Helic. Vivent. i. p. 416"; Reeve, Conch. Icon. vii., 
Helix, t. 120. fig. 712"; Binney, Terr. air-breath. Moll. of N. Am. iii. p. 17", and iv. 
p. 92, t. 78. figg. 5,6,8"; Bland, Ann. Lyc. N. York, viii. p. 32 (1863); Binney & 
Bland, Land and Fresh-water Shells of N. Am. 1. p. 93”. 
Helix (Polygyra) hindsi (Pfr.), Fisch. & Crosse, loc. cit. p. 273 ”. 
Dedalochila hindsi (Pfr.), Tryon, Am. Journ. Conch. iii. pp. 63, 79, t. 5 (10). figg. 24, 44 (not 
good) (1867) *. 
Polygyra hinds: (Pfr.), Binney, Terr. air-breath. Moll. of N. Am. v. p. 269%; Manual of Am. 
Land-Shells, p. 368 *. 
Hab. Norra America: Texas 14717 21-25, 
? Mexico, without nearer indication of locality 21~*° (Hinds 14~1®). 
Easily recognizable by the two teeth on the lower margin of the aperture. According 
to Pfeiffer 14, his Helix (Polygyra) hindsi is not only much smaller (8 millim. in diam.) 
than P. ventrosala (13 millim. in diam.), but is also distinct by reason of its less inflated 
shell and more open umbilicus. He even places P. hindsi in the section “ pervio-umbili- 
cate” and P. ventrosula in another section “ oblique et impervie umbilicate”: in the 
figures given by himself? the umbilicus of P. ventrosula is distinctly narrower than 
that of P. hindsi, but also well rounded, not “rimato-perforata.” Of two specimens 
collected by Forrer on the Tres Marias Islands, the larger one (fig. 10), 12 millim. in 
diam., has the umbilicus as widely open and pervious as Pfeiffer’s figure of P. hindsi, 
BIOL. CENTR.-AMER., Terr. and Fluviat. Mollusca, Apri/ 1892. 22 
