70 BRACHYPODELLA, S. STR. 



embryonic ones smooth, paler, following ones costulate, sub- 

 compressed, slightly sub angular at the suture ; last whorl sub- 

 tetragonal, free in front, shortly drawn out, a little descend- 

 ing, angular at the side and carinate below, at its junction 

 with the external margin frequently costulate. Aperture 

 irregularly rounded-subquadrangular, somewhat channelled 

 at the base, whitish inside; peristome continuous, somewhat 

 thickened, a little expanded, subreflexed, glossy, white. Length 

 16, diam. 3 mm. ; aperture with peristome scarcely 2 mm. long 

 and wide (Crosse & Fischer). 



Northern Guatemala: walls of the cave Jobitsinal, near the 

 capital of Peten (Morelet). Yucatan: cave at Tabi, Ticul, 

 and between Sitilpech and Tunkas; a small form at Labna 

 (Heilprin exped.). 



Cyl. costulata MOREL., Testae. Noviss., ii, p. 12 (1851) ; not 

 of C. B. Ad., 1849. C. speluncce PFR., Zeitschr. f. Malak., 

 1852, p. 151 ; Monogr., iii, p. 577. FISCHER ET CROSSE, Miss. 

 Scient. au Mex. Moll., i, p. 410, pi. 17, f. 11. Holospira 

 speluncce v. MART., Biologia, p. 284. Cyl. speluncce PILSBRY, 

 Proc. A. N. S. Phila., 1891, p. 315, pi. 15, f. 15, 15a, with var. 

 dubia, p. 316, pi. 15, f. 14, Ua (Aug. 25, 1891). 



B. speluncce is closely related to B. morini, but it has fewer, 

 more widely-spaced riblets, the peristome is less reflexed and 

 more fragile, and the whorls are less convex. 



Crosse and Fischer's description of Morelet 's type is given 

 above, and their figures copied, pi. 6, figs. 17, 18. Their 

 measurement of diameter includes the lip of the shell, and 

 hence exceeds by a millimeter the measurement as taken in 

 this work. It is a common species in Yucatan. The first 

 three whorls, in entire specimens, have a sculpture of exces- 

 sively fine, close, vertical striae; then coarse riblets abruptly 

 set in (pi. 6, fig. 14, apex of a shell from Ticul). Fig. 13 is 

 drawn from a specimen taken at Tabi. 



An entire specimen taken from Ticul measures 14.3 x 2 mm., 

 with 22 whorls, and has 16 riblets on the penult, whorl. 

 Truncate shells from the cave at Tabi measure 10 to 12 mm., 

 with 12 to 13% whorls, with about 14 riblets. The slender 

 axis has a spiral lamella as in B. morini. 



