URqCOPTIS, S. G. GONGYLOSTOMA. 281 



white ribs, which are hollow, rounded at their summits, and 

 parted by intervals of double their width. Whorls moderately 

 convex, the latter half of the last free, descending in a round, 

 contracted neck. Aperture slightly oblique; circular, brown, 

 the peristome being rather broadly reflexed, white above, 

 brown below. Axis straight, slender, encircled by a single 

 simple spiral cord, not spinose even in the upper whorls. In 

 some whorls a second very weak cord appears above it (pi. 64, 

 fig. 14). 



Length 12, diam. 2.9 mm.; whorls 13 (entire). 



Length 12, diam. 3 mm.; whorls 10 (truncate). 



Western Cuba: Pan de Guajaybon, Pinar del Rio (Gund- 

 lach, Wright). 



Cyl. blainiana Gundl. mss., PFR., Malak. BL, xi, 1863, p. 13 ; 

 Novit. Conch., p. 252, pi. 63, f . 30-35 ; Monogr., vi, p. 379. 

 ARANGO, Contrib., p. 119. C. scopulosa Gundl. on labels. 

 ? C. scopulorum GdL, SCHAUFUSS in Paetel's Catal., p. 68. 



This species presents the most extraordinary parallelism to 

 U. (Callonia) dautzenbergiana in the dull luster of the maroon 

 surface, set with snow-white, hollow riblets. The spire is 

 shaped as in Macroceramus, the postnepionic whorls not being 

 contracted as" in other species of this group. Figs. 5, 6 are 

 copied from Pfeiffer ; figs. 7, 8 are from Guajaybon examples. 

 I have not examined the dentition. 



Var. aurea Pils. (pi. 65, fig. 13) . Differs by its light golden 

 brown color, narrower and more widely-spaced ribs, and the 

 noticeably more slender form. 



Species of unknown systematic position. 



Probably all the following belong to Gongylostoma in the 

 wide sense, and if so are from western or perhaps central 

 Cuba: 



U. LUCENS ('Wright' Sowerby). Vol. XVI, PL 11, fig. 73. 



" Shell subpyramidal, narrow, whitish, semi-pellucid; 

 whorls 12, gradually increased, convex, last rather narrow, a 

 little unwound; aperture rather round, depressed above, 

 cuneate " (Sowb.). 



