POLYGYRA. 165 
S.W. Mexico: Isthmus of Tehuantepec (Sailé %). 
Yucatan : on the shore (Morelet } 28), 
Distinct from P. implicata by the upper external tooth being waved or folded 
(“complicatus”). The specific name signifies “ stopped” or “ locked up.” 
3. Polygyra dysoni. 
Helix dorfeuilleana, Pfr. Monogr. Helic. Vivent. i. p. 410'; in Martini & Chemnitz, Syst. Conch.- 
Cab. ed. 2, Helix, i. p. 377. no. 391, t. 65. figg. 25-28°; ? Reeve, Conch. Icon. vii., Heliz, 
t. 120. fig. 713 (not good’) (nec Lea). 
Helix dysoni, Shuttl. in Bern Mittheil. 1852 (Diagn. no. 2, p. 16), p. 196‘; Pfr. Monogr. Helic. 
Vivent. iv. p. 315”. 
Hab. Honvuras (Dyson '~). 
Parietal fold simple, as in P. plagioglossa; umbilicus widely open, and external 
teeth simple, as in P. ¢mplicata. 
4. Polygyra chiapensis. 
Helix chiapensis, Pfr. P. Z. 8. 1856, p. 377° ; Malak. Blatt. 1856, p. 230°; Monogr. Helic. Vivent. 
iv. p. 315°. 
Helix (Polygyra) chiapensis (Pfr.), Fisch. & Crosse, Miss. Scient. Mex., Mollusca, i. p. 281 '. 
Hab. Cutapas (Ghiesbreght 1~*). 
_ According to the description’, this species agrees with P. dysont and P. plagio- 
glossa by the simple, not two-branched, parietal fold; but the spire seems to be more 
elevated (‘* breviter conoidea ”), the umbilicus smaller, though open (“ pervius”), and the 
basal tooth very faint (‘* basali denticulo obsoleto ”). 
5. Polygyra mooreana. 
Helix (Polygyra) mooreana, Binney, Proc. Acad. Phil. ix. p. 184 (1857)*; Fisch. & Crosse, Miss. 
Scient. Mex., Mollusca, i. p. 275°. 
Helix mooreana, Binney, Terr. air-breath. Moll. of N. Am. iv. p. 80, t. 78. fig. 24°; Pfr. Monogr. 
Helic. Vivent. iv. p. 352°; Binney & Bland, Land and Fresh-water Shells of N. Am. i. 
p. 95, fig. 170°. | 
Dedalochila mooreana (Binn.), Tryon, Am. Journ. Conch, ii. pp. 64, 78, t. 3 (10). fig. 8 (1867) °. 
Polygyra mooreana, Binney, Terr. air-breath. Moll. of N. Am. v. (Bull. Mus. Comp. Zool. Harv. 
7 
Coll. iv.) p. 271, fig. 170, and t. 6. fig. Q (radula)*; Manual of Am. Land-Shells, pp. 360 
— (jaw), 370, fig. 405°. 
Helix texasiana, var. minor, in some collections. 
Hab. Nort America: Washington County !°%, Bosque County‘ *, Texas; ‘Texas 
(PF. Romer). 7 
N. Mexico: North Mexican States adjoining 'Texas?°7 6, 
?CentTRAL Mexico: Leon (Lieut. Blake *). 
