UROCOPTIS, S. G. IDIOSTEMMA. 173 



Length 17.6, diam. 2.5 mm. ; whorls 16. Yunque ; normally 

 truncate. 



Length 21.5, diam. 2.5 mm. ; whorls 19. Yunque ; normally 

 truncate. 



Length 27, diam. 2.3 mm. ; whorls 33. Spire complete. 



Eastern Cuba: Yunque de Baracoa, on rocks and stones 

 (Gundlach). 



Cyl. lateralis Paz mss., PFR., Malak. Bl. vii. 1860, p. 21; 

 Novit. Conch, p. 263, pi. 65, f . 26, 27 ; Monogr., vi, p. 376. 

 ARANGO, Contrib., p. 118. 



Related to U. fastigiata, but very distinct by its ribless sur- 

 face, tapering shape, many convex whorls and more slender 

 pillar. The typical form (figs. 55, 57, 58) is almost or quite 

 free from sutural and basal nodules, but specimens with 

 these vestiges of ribs (fig. 54) occur with them. Those illus- 

 trated are from the ''Yunque" of Baracoa, the only locality 

 yet known. 



The ribs on the internal pillar give the impression voiced 

 by Arango that the column is sinistrally plicate; but they 

 are of the same nature as the oblique ribs in other species of 

 this group, and further examples of homoplastic structure 

 occur in Ccelostemma, Ccelocentrum, etc. 



The nepionic whorls are vertically, delicately ribbed (pi. 

 46, fig. 59). 



Section MACEO Pils. & Van., 1898. 



PILSBRY & VANATTA, Proc. A. N. S. Phila. 1898, pp. 270, 

 275. Type and sole species U. interrupta Gundl. 



Urocoptis with a single stout axial lamella median in each 

 whorl, the rounded edge of which is closely crenulate or 

 "milled" (pi. 46, fig. 61). 



The single species is from eastern Cuba. Sectional name 

 to honor a Cuban patriot. 



While at first sight the axis is quite unlike that of Idio- 

 stemma, it is in reality only a modification of the type seen 

 in U. fastigiata, produced by the upper edge of the callous 

 band around the axis of that species becoming much more 

 prominent, and the lower edge diminishing. The fine crenu- 



