170 MOLLUSCA. 
and the smaller one (fig. 11), 10 millim. in diam., has a similar umbilicus; both 
are somewhat more depressed than Pfeiffer’s figures, but it is probable that his 
P.. ventrosula has the appearance of being somewhat more inflated than the shell 
really was, as it is drawn not exactly in profile, but somewhat from below. 
‘Binney’s figures of P. ventrosula*’ 1218 give the general form of the shell very 
well. It appears that there is a large amount of variation in the size, and also to some 
extent in the comparative narrowness, of the umbilicus and in the elevation of the 
spire. | 
The teeth of the aperture are exactly similar in the three specimens now before 
me—the two collected by Mr. Forrer, and one “ P. hindsi” of 8 millim. in diam.— 
viz., a very distinct blunt one at the lower end of the outer margin of the aperture, and 
above it, separated by a small notch, a subvertical elongated compressed tooth, parallel 
to the margin, somewhat more feeble in the middle, and swelling towards both ends, 
the upper and the lower ; on the basal or lower margin two biunt teeth, the outer one 
larger than the other, the inner one broader than high. The plait on the inner side 
of the aperture is very distinctly two-branched ; but its ends are not contiguous with 
the insertion of the upper and lower end of the outer margin. In this respect there 
may be some variation, as in Pfeiffer’s drawing they are contiguous, and also his 
description says “‘ marginibus ... callo bicruri junctis” and “marginibus ... lamellas 
in ventre anfr. penultimi angulatim junctas emittentibus.” In all other respects 
Pfeiffer’s description, and his drawing of the teeth (fig. 5)2, agrees very well with our 
specimens. Less accurate is the drawing of the teeth in his figure 7 (hindsi) and 
in that of Tryon and Binney. Tryon’s fig. 35 (ventrosula)"™ and Binney’s fig. 167 
(hinds?) *!, repeated in his three works 23 24 25, are so incorrect with regard to the teeth 
of the aperture that I would not even quote them. 
13. Polygyra texasiana. 
Helix texasiana, Moricand, in Mém. Soc. d’hist. Nat. de Généve, vi. p. 538, t. 1. fig. 2 (1833)?; 
Deshayes in Lamarck’s Hist. Nat. d’anim. sans vert. ed. 2, vill. p. 183°; Pfr. Monogr. 
Helic. Vivent. i. p. 418°; in Martini & Chemnitz, Syst. Conch.-Cab. ed. 2, Helix, i. p. 85. 
no. 56, t. 10. figg. 11, 12*; Ferd. Romer, Texas, p. 455 (1849) °; Deshayes, in Férussac’s 
Hist. Nat. des Moll. terr. i. p. 74, t. 69 p. fig. 2 (good) °; Binney, Terr. air-breath. Moll. 
of N. Am. ii. p. 191, t. 45. fig. 17; Reeve, Conch. Icon. vil., Helix, t. 120. fig. 707°; 
Bland, Ann. Lyc. New York, viii. p. 32 (1863) °; v. Mart. in Malak. Blatt. xii. p. 22 
(1865) °; Binney & Bland, Land and Fresh-water Shells of N. Am. i. p. 93. fig. 168", and 
Suppl. i. p. 151” 
Dedalochila texasiana, Tryon, Am. Journ. Conch. iii. p- 62 (excl. fig.) (1867) *. 
Helix (Polygyra) texasiana (Moric.), Fisch. & Crosse, Miss. Scient. Mex., Mollusca, i. p. 279°. 
Polygyra texasiana (Moric.), Binney, Terr. air-breath. Moll. of N. Am. vy. (Bull. Mus. Comp. 
Zoél. Harv. Coll. iv.), p. 270, t. 6. fig. 9 (radula) *; Manual of Am. Land-Shells, p. 369. 
fig. 403° ; Strebel, Beitr. Mex. Land- und Siissw.-Conch, iv. p. 46, t. 15. fig. 13". 
