GAZA. 161 



screw thread. Pillar straight, thin, with no callus ; aperture 

 rounded except at the angle of the umbilical carina ; margin thin, 

 sharp, not reflected or thickened ; no callus on the body whorl in 

 the aperture ; shell whitish or greenish ; nacre less brilliant in dead 

 or deep-water specimens; with zigzag brown lines variously trans- 

 versely disposed and disappearing on the base. 



Alt. 4'0 maj. diam. 6'75 ; of umbilicus, l'7o; of aperture, 2*5 

 mill. (Dall) 



Of Barbados, in 100 fms. ; off Baliia Honda, Cuba, 220 fms. ; 36 

 miles S. J W. from Cape Hatteras, N. Carolina, in 124 fms. 



The operculum is like that of Gaza, and has six or seven whorls. 

 None of the specimens show any tendency to a reflected lip, yet it 

 is, of course, possible that no completely adult specimen was ob- 

 tained. The animal has a short stout foot, bluntly rounded at either 

 end. It is of a pinkish tint. The tentacula are very long and the 

 eyes large. The muzzle is rounded and not very long, its ex- 

 tremity plain. There are no frontal lobes. The epipodium has a 

 very small anterior lobe with a cirrus behind it, then a space with- 

 out cirri, a long process just in front of the opercular disk, and one, 

 shorter, under it on each side making three in all. There is no 

 posterior point to the epipodium, and only the above three cirri on 

 each side. The jaw is somewhat like that of Umbonium, but shorter 

 and broader. The radula, however, bears no resemblance to that 

 of Umbonium (Rotella Lam.). The teeth are very elegant. The 

 rhachidian tooth in general form (except the cusp) not unlike that 

 of Calliostoma granulata Born (Troschel, II, pi. xxiv, fig. 18), but 

 the central spur of the cusp is long and slender like a stiletto, ex- 

 tending considerably behind the posterior edge of the base of the 

 tooth. On each side of it are four stout sharp rather short denticles, 

 radiating as from the median point of the front edge of the cusp. 

 The laterals recall those of Gibbula divaricata (Troschel, loc. cit., 

 fig. 6), but have more, larger, and stronger denticles, all on the 

 posterior edge of the cusp, or the edge away from the rhachis, the 

 uncini are rather few in number, the cusps sword shaped, sigmoid, 

 the inner ones denticulated on both edges. The number of laterals 

 is five. The radula as a whole is very short and small. 



. The depressed form and marginated suture, as well as the kind 



of coloration, in this shell recall Umbonium. The texture of the 



shell and the character of its umbilicus are precisely as in Callo- 



gaza. The soft parts indicate its place to be in that vicinity. 



11 



