242 MOLLUSCA. 
Mexico 3-6 13, without nearer indication of locality (Schiede’*; Hegewisch? ¥ ; 
Uhde!2; David, in coll. Dunker). 
Var. patriarcha. 
Bulimus patriarcha, Binney, Proc. Acad. Phil. 1858, p. 116” ; Terr. air-breath. Moll. of N. Am. 
iv. p. 180, t. 80. fig. 13°; Pfr. Monogr. Helic. Vivent. vi. p. 148 a 
Thaumastus patriarcha, Tryon, Am. Journ. Conch. iii. p. 171, t. 9 (18). fig. 15 *. 
Bulimulus patriarcha, Binney & Bland, Land and Fresh-water Shells of N. Am. i. p. 200, fig. 346” ; 
Binney, Terr. air-breath. Moll. of N. Am. v. p. 388, fig. 270 *° ; Manual of Am. Land-Shells, 
p. 396, fig. 431. 
Bulimulus (Thaumastus) patriarcha, Fisch. & Crosse, Miss. Scient. Mex., Mollusca, i. p. 564. 
Hab. Nortn America: Texas 7° 25 30 91, 
N.E. Mexico: Buenavista (N.W. of Linares, in the State of Nuevo Leon) (Ber- 
landiére 25 6 29 31, Couch ?°). 
Mexico, without nearer indication of locality *°. 
Pfeiffer 2 states that the shells of this species are pierced and strung by the peasants, 
and sold in Mexico. 
I have examined 352 specimens from various localities, 335 of which are from 
Tehuacan, collected either by Hége or Uhde, forty-six belonging to the larger and 
smoother variety ; none of them show the well-defined columellar tubercle of B. alter- 
natus. The greatest length of the shell is 30 millim., the greatest diameter 17, but 
these dimensions are not found united in any specimen ; the proportion of the diameter 
to the length of the shell in the same specimen varies from 1:27 to 1: 1%, that of the 
aperture to the whole length from 1:2 to 1:23. These differences are chiefly caused 
by the degree of involution: if the following whorl envelops a little more of the 
preceding, it extends nearer to the periphery, and the shell becomes broader and more 
ventricose, and the aperture larger; if the following whorl envelops a smaller portion 
of the preceding, it extends further downwards, and the shell becomes more elongate 
and the aperture proportionately smaller. The most elongated specimens somewhat 
approach B. callosus, Philippi, from Atacama; but they show neither the rough 
sculpture, the blunt apex, nor the thick parietal callus in the aperture of that species. 
I have figured some of the different forms, all collected at Tehuacan by Hoge. The 
colour externally is opaque white, without stripes, inside the aperture is generally 
ochraceous, more rarely white. 
The variety is on the average larger, with the shell more regularly ovate, though 
not very different in size and form; its surface is smoother, even a little shining, 
generally also equally white, but in some specimens with a few scattered, pale grey or 
even pale brownish stripes, inside of mouth more deeply brown. In most of these 
respects it approaches B. alternatus. I have seen forty-seven specimens of it from 
Tehuacan: the longest of them measures 36 millim. in length, the broadest 18 
