SOUTH AMERICAN OBELISCUS. 253 



ered with a chestnut-tinged yellow or olive-yellow cuticle, 

 paler above and worn from the upper whorls. A narrow 

 sutural margin is conspicuous, but occasionally obsolete. 

 The spire remains thick until quite near the .apex. The outer 

 lip is decidedly arcuate in side view (fig. 58), but the aper- 

 ture is vertical, not oblique as in 0. major. Well-grown speci- 

 mens measure 67 x 16.8 mm., aperture 20 mm., and have 11 

 whorls. 



The columella in uterine young shells is distinctly trun- 

 cate obliquely, and this sinuation may be seen near the apex 

 in sections of adult shells. Elsewhere the axis is straight 

 and slender. A dried specimen opened by me contained 8 

 embryonic shells, the largest 4.7 mm. long, 3.6 wide, with 3 

 whorls. Like the adults, they are iniperforate (pi. 37, fig. 

 102). Miller mentions finding 12 embryos in a specimen he 

 opened. The synonymous B. fairmairianus is figured, fig. 59. 

 Figures 56, 57 are Pfeiffer's type of cuneus. 



Var. minor Miller. PI. 35, fig. 63. Whorls 10, length 36, 

 d'iam. 9, aperture 10 x 5 mm. ; only a trace of the subsutural 

 line; striation more distinct. With cuneus in the Val de 

 Pilaton. The name is preoccupied by Pfeiffer for a form of 

 0. riparius, and Miller's variety is probably referable to 0. 

 major. 



Var. RIPARIUS (Pfeiffer). PI. 35, figs. 61, 62. 



Shell imperforate, turrite, solid, striate, opaque, straw- 

 colored. Spire long, the apex rather obtuse; suture linear, 

 very closely crenulate, not margined. Whorls 11, slowly in- 

 creasing, flat, the last less than one-fourth the total length, 

 rounded 'basally. Columella slightly twisted, then vertically 

 descending. Aperture small, acuminate-oval ; peristome sim- 

 ple, unexpanded, the right margin lightly arcuate, columellar 

 margin a little reflexed. Length 53, diam. 11, aperture 

 12.5x6.5 mm. (P/Y.). 



Ecuador: banks of the Mira river (Bourcier) ; Baeza, San 

 Jose, among plants in very damp places (Martinez). 



Bulimus riparius PPR., Proc. Zool. Soc., 1852, p. 155; 

 Conchy!. Cab., p. 97, pi. 32, f. 13, 14; Monogr., iii, p. 391; 



