POTAMIDES. 571 
2. Potamides montagnei. 
Cerithium montagnei, d’Orbigny, Voy. Am. mér., Moll. p. 443, t. 63. figg. 3, 4 (1835-43) "; Kiener, 
Iconogr. p. 99, t. 50. fig. 1 (1842) 2; Menke, Zeitschr. f. Malak. 1850, p. 178°; Eydoux et 
Souleyet, Voy. Bonite, Moll. t. 39. figg. 6, 7‘; Sowerby, Thes. Conch. ii. p. 888, t. 186. 
figg. 284, 286 (juv.)°; Kobelt, in Martini & Chemnitz, Syst. Conch.-Cab. ed. 2, Cerithium, 
p. 54, t. 11. fige. 5, 6°. | 
Cerithidea montagnei, Carpenter, Catal. Mazatlan Shells, p. 3427; Report Moll. W. Coast of N. 
Am. p. 825 (1857)*°; Moll. W. N. Am. pp. 24, 27, 151 (1872)°; Reeve, Conch. Icon. xv., 
Cerithidea, t. 4. fig. 26°°. 
Potamides montagnei, Tryon, Manual of Conch. ix. p. 161, t. 33. fig. 57" (copied from Reeve) 
(not fig. 58). 
Cerithium reevianum, C. B. Adams, Ann. Lyc. Nat. Hist. N. York, v. p. 880 (1852) ”. 
Cerithidea reeveana, Mérch, in Malak. Blatt. vii. p. 19 (1861) ™. 
Hab. Lowsr Cattrornia: La Paz (Major Rich ®); Cerro Island (Dr. Ayres & Dr. Veitch®). 
N.W. Mexico: Mazatlan, common (Melchers*, Reigen"). 
W. Guatemata: Champerico ‘Champion). 
W. Costa Rica: Punta Arenas (Grsted }°). 
S. PanaMaA, not uncommon, half buried in muddy sand, under bushes, at high-water 
mark, near the mangrove thicket, 24 miles east of Panama (C. B. Adams). 
Ecvapor: Guayaquil, in brackish water of the river of that name, with P. varicosus 
(d’ Orbigny '). 
Full-grown specimens vary considerably in size, from 32-33 (1?) to 44 millim. (1°) in 
length, 154-25 millim. in the diameter of the last whorl, including the peristome, and 
12-18 millim. in the length of the aperture. 
Var. pulcher. 
Cerithium montagnei, Sowerby, Thes. Conch. ii. t. 185. fig. 285 ™. 
Cerithium pulchrum, C. B. Adams, Ann, Lyc. Nat. Hist. N. York, v. p. 380°; Kobelt, loc. cit. 
p. 98, t. Jl. figs. 7,8°°. . 
Cerithidea pulchra, Carpenter, Report Moll. W. Coast N. Am. p. 272.7; Moll. W. N. Am. 
p. 186°; Mérch, Malak. Blatt. vii. p. 80°; Reeve, Conch. Icon. xv., Cerithidea, t. 4. 
fie, 39”. 
Patamides montagnei, var. pulchra, Tryon, Manual of Conch. ix. p. 161, t. 34. fig. 50 (copied from 
Reeve)”. 
With one varix and the ribs somewhat nodulous by crossing the spiral strie. General form comparatively 
broader, and the peristome more darkly coloured, but these last-mentioned differences do not hold good 
in all specimens. Size the same as in the smaller full-grown specimens of the typical form. 
Hab. §. Panama, with the typical form (C. B. Adams '*~°°). 
At first sight, the var. pulcher seems to be sufficiently distinct. from P. montagne by 
the cancellated appearance of the sculpture and by the presence of a varix in the last 
five whorls, both characters bringing it near P. varicosus; but on a closer examination 
bs 
