166 UROCOPTIS, S. G. IDIOSTEMMA. 



rest, uncata, intusmaUeata, geminata, fastigiata and inter- 

 rupta, have the same type of external sculpture, but they have 

 diverged widely in the sculpture of the axis. The relation- 

 ships of the species may be approximately represented by a 

 diagram : 



interrupt a 



uncata intusmaUeata fastigiata 



| geminata lateralis 



perlata 

 IcBvigata 



pilotensis 



39. U. UNCATA ('Gundlach' Pfr.). PL 44, figs. 31, 32, 33. 



Shell cylindric, slightly tapering above to a rather wide 

 truncation (or sometimes retaining a long, attenuated juve- 

 nile stage), rather thin, whitish. Surface lustreless, roughly 

 sculptured with coarse ribs, which are swollen above and below 

 near the suture, and are continuous from whorl to whorl; 

 these ribs are wider, more inflated on the upper than on later 

 whorls, and are hollow, usually in part broken; the intervals 

 very finely, irregularly striate. Whorls about 15 in normally 

 decollate shells, hardly convex, the last free in front, exca- 

 vated below the periphery, striate beneath, the neck tumid at 

 the periphery. Aperture transversely obliquely ovate. Peri- 

 stome narrowly reflexed. Axis rather stout in the cylindrical 

 portion, each whorl having two opposite pairs of swollen 

 hooks, one hook of each pair above, the other below, partially 

 adnate to the partitions. In the tapering whorls the axis is 

 slender and simple, and hooks are wanting in the later 1% 

 whorls (fig. 33). 



Length 1,9, diam. 4 mm. ; whorls 15. 



Length 17, diam. 3.8 mm. ; whorls IS 1 /^- 



Length 22y 2 , diam. 4 mm. ; whorls 22i/ 2 . 



Eastern Cuba: Yateras and Monte Libano, jurisdiction of 

 Guantanamo, under stones (Gundlach) ; Farallones, in south- 

 ern part of prov. Santiago (Chas. Wright). 



Cyl. uncata GUNDL., PFR., Malak. Bl., vi, 1859, p. 97 ; Novit. 



