88 PLEKOCHEILUS-EURYTUS. 



somewhat inflated on the back, flattened toward the aperture, deeply 

 descending in front, subdilated beneath. 



Columella narrow, oblique, twisted inward, visible inside from the 

 base as far as the apex. Aperture ovate-acute, subdilated below, 

 three-fifths the length of the shell, within concolored ; peristome 

 simple, sometimes somewhat thickened, narrowly expanso-reflexed 

 throughout, purple-brown ; the terminations joined by a very thin 

 callus ; right margin well arched, columella slightly dilated above, 

 adnate. Alt. 38, diam. 23 mill. 



Baeza, Ecuador (Martinez). 



B. semipictas HID., Journ. de Conch., xvii, 1869, p. 188; xviii, 

 1870, pi. 6, f. 7 ; Moll. Viaje al Pacif., p. 95, pi. 6, f. 8, 9. 



In the majority of its characters, according to Hidalgo, this form 

 is like B. tricolor Pfr., but it differs in the more obtuse spire, larger 

 aperture, diverse direction of the columella, fewer color-lines and 

 lack of granulation on the last whorl, though with a high power lens 

 granulation is visible on the second whorl. 



P. ARIST^EUS Crosse. PI. 4, fig. 4. 



Shell nearly covered rimate, irregularly ventricose-oval, longitu- 

 dinally wrinkle-striate ; olive-chestnut, with sparse zig-zag streaks 

 and spots of blackish-brown, nearly disappearing on the last whorl. 

 Spire rather short, the apex obtuse ; suture well marked. Whorls 

 4?, somewhat convex, the nepionic H smooth and polished, violet- 

 purple; penultimate whorl strongly convex; last whorl deeply ob- 

 liquely descending, carried forward, large, inflated, much longer 

 than the spire. 



Columella perceptibly receding, white within ; aperture oval, sub- 

 piriform, moderately large, soiled white within ; peristome pale 

 chestnut whitish, somewhat thickened, narrowly reflexed, the mar- 

 gins somewhat converging, joined by a very thin callus; columellar 

 margin flat, slightly dilated. Alt. 48, diam. 27 mill. ; aperture 

 (with peristome) alt. 27, width 18 mill. (Crosse). 



Quito, Ecuador (Paz.). 



B. aristceus CROSSE, Journ. de Conch., xvii, 1869, p. 185; 1870, 

 p. 105, pi. 6, f. 5. 



Group of P. taylorianus. 



Ovate, imperforate, the lip and columella narrow, not expanded ; 

 suture abruptly descending in front, the whorl flattened there. 



