76 PLEKOCHEILUS-EURYTUS. 



Aperture very large, ovate, purple-brown with a pearly luster 

 within; peristome brown, well expanded throughout. Columella 

 widened and white above, brown and concave below, passing upward 

 in a long, gently convex fold. Parietal callus thin, whitish. 



Alt. 84, diam. 65 ; aperture, alt. 57, width 46 mill. 



Alt. 80, diam. 58 ; aperture, alt. 52, width 40 mill. 



U. S. of Colombia, between La Plata and Tocaima (Gibbon) ; 

 between Guaduas and Villeta (Bland) ; Quenden Mts. (Pfr.). 



Bulimm gibbonius LEA, Descr. New Freshwater and Land Shells, 

 Trans. Amer. Philos. Soc. vi, p. 85, pi. 23, f. 99 (1836) ; Obs. Genus 

 Unio, etc.. ii, p. 85, pi. 23, f. 99. PFR., Monogr.,ii, p. 51. REEVE, 

 C. Icon., pi. 32, f. 196. BLAND, in Ad., Contr. to Conch., No. 11, 

 p. 229. 



Differs radically from B. castaneus in sculpture; from B.jimin- 

 ezi in form of the columella, and from B. coloratus var. ampullar- 

 oides in the slenderer spire, widened, white columella, etc. 



P. EPISCOPALIS Pfeiffer. Unfigured. 



Shell narrowly umbilicated, ovate-conic, thin, longitudinally sub- 

 rugose-striate and minutely granulated, sometimes with transverse 

 grooves. Olivaceous-tawny, with irregularly scattered reddish spots. 

 Spire conic, rather acute. Whorls 4?, the upper slightly convex, 

 the last about two-thirds the shell's length, obliquely descending, 

 arcuately subascending at aperture, the base slightly attenuated. 

 Columella lightly, compressedly folded. Aperture angulate-oval, 

 lilac colored within ; peristome purple, expanded and narrowly re- 

 volute, the columellar margin subappressed. 



Alt. 58, diam. 27 mill. ; aperture 38 mill, long, inside 19 wide. 

 (P/n). 



Bogota (Cuming coll.). 



B. episcopalis PFR., P. Z. S., 1855, p. 115 ; Monogr., iv, p. 379. 



A smaller variety is mentioned by Pfeiffer, alt. 47, diam. 22 mill. 



Form like B. taylorianus Rve., but the rest of the characters ap- 

 proaching B. pulicarius Rve. ; differing in size, formation of the col- 

 umellar fold and the widely expanded peristome. 



P. CORTICOSUS Sowerby. PI. 3, fig. 8. 



Shell narrowly perforate, ovate-conic, solid, most minutely gran- 

 ulated throughout ; dark brown, with obscure scattered dots and 



