PLEKOCHEILUS-EURYTUS. 87 



liquely descending. Coluraella oblique, narrow, twisting inward, 

 its spiral ascent to the apex being visible from below ; aperture am- 

 ple, ovate-acuminate, shining and pale blue tinted within, about five- 

 sevenths the shell's length. Peristome simple, narrowly expanded, 

 hardly reflexed, fleshy-brown ; the margins joined by a very thin 

 callus; right margin strongly arched, columellar margin narrow, 

 subreflexed. Alt. 75, diam. 47 mill. (Hid.*). 



San Jose, Ecuador (Isern). 



Bulimus gibbonius HID., Joum. de Conchyl., xviii, 1870, p. 54; 

 Moluseos del Viaje al Pacifico, pi. 5, f. 2, 3. B. jimenezi HID., t. c. 

 p. 93. 



Distinguished readily from B. gibbonius, coloratits, ampullaroides, 

 etc., by the narrow columella, the spiral trend of which to the apex 

 may be seen from the base. 



P. TRICOLOR Pfeiffer. PI. 35, figs. 74, 75. 



Shell subperforate, ovate, thin, striate and minutely granulate; 

 olive-brown, with oblique, interrupted lighting stripes of deep chest- 

 nut. Spire ventricose-conic, the apex red and rather acute; suture 

 denticulate-marginate. Whorls 4, the upper 2 rather flat, the last 

 ventricose, very obliquely descending at the latter part, attenuated 

 at base. Columella simple, arcuate; aperture small, slightly longer 

 than spire ; oblong-oval ; peristome reddish-fleshy, somewhat thick- 

 ened, slightly expanded, the columellar margin dilated and reflexed 

 above. Alt. 42, diam. 21 mill. ; aperture 22 mill, long, 13 wide. 



Gualea, Ecuador (Bourcier). 



B. tricolor PFR., P. Z. S., 1852, p. 154; Monogr., iii, p. 325; 

 Conchyl. Cab., p. 95, pi. 32, f. 17, 18. 



The following is evidently a variety of this, as Hidalgo himself 

 suspected. 



Var. SEMIPICTUS Hidalgo. Pi. 5, figs. 24, 25 ; pi. 8, fig. 41. 



Shell subimperforate, ovate, thin, subpellucid, but little shining, 

 rather smooth. Whitish, the earlier whorls with narrow oblique 

 " lightning " stripes, the last with sparse dots of the same color, van- 

 ishing toward the aperture; covered with an olivaceous cuticle. 

 Spire conic, apex rather obtuse, purple-brown ; suture simple, some- 

 times slightly creuulated. Whorls 4, subplanate, rapidly increasing, 

 the earlier 2 seen to be minutely wrinkled under a lens, the last 



