254 SOUTH AMERICAN OBELISCUS. 



vi. p. 91, var. minor. HIDALGO, Journ. de Conch., 1870, p. 

 55 ; Viaje al Pacifieo, p. 98. 



This form, of which I reproduce the original description 

 and figures, is probably not separable from 0. cum ux. 

 Hidalgo and Miller have remarked on the great similarity, 

 the former adding that riparius is paler, with a proportion- 

 ally smaller aperture, obtuse apex, no subsutural line, and a 

 less convex last whorl. Pfeiffer, in Monographia VI, men- 

 tions a minor form, 29-30 mm. long, 8.5 wide, aperture 8 

 mm. long. 



10. 0. MAJOR (Miller). PI. 35, fig. 6-i. 



Whorls lli/o ; length 86, diain. 21, aperture 22 x 12 mm. 



Ecuador: Val -de Pilaton, about 3,000 meters above sea 

 level (Boetzkes). 



Obeliscus cum us var. major MILL., Malak. Bl., n. F., i, 

 1879, pi. 6, f. 3 b. 



Miller's figure seems to represent a form which differs 

 from 0. cuneus by the conspicuous attenuation or contraction 

 of the upper portion of the spire, the oblique aperture and 

 the concave, subsinuous columella. There is no subsutural 

 margining impressed line. I have figured a series from the 

 collection of the Academy, pi. 35, figs. 60, 65, 66, 67. 



The shell is imperf orate, rather thin, but moderately strong, 

 covered with a greenish-yellow, smooth and rather glossy 

 cuticle. The spire tapers slowly, but at the upper fourth 

 more rapidly, so that near the su))nnit it is distinctly atten- 

 uate. Whorls lli/2, the earlier ones convex, rather narrow 

 and slowly widening ; the last four whorls are very wide a.nd 

 a I most flat, the last whorl being a little more convex than the 

 preceding. Suture linear, quite oblique, pale-edged below, 

 slightly arched forward. Columella narrow, concave below, 

 ascending in a long, weak spiral, the edge reflexed and ap- 

 pressed above; parietal callous thin, transparent. Length 

 71.8, diam. 16, longlh of aperture 19.5 mm. 



Ecuador: Quito (purchased by R. Swift from John Cal- 

 vert, 167 Strand, London).' 



The contrast between this form and 0. cuneus in the shape 



