150 POKPHYKOBAPHE. 



a. Lip blunt, not expanded or reflexed, brown or white, the colu- 

 mella ami parietal callus pale ; profusely mottled, and with 

 several pale, bands; finely decussated. dennisoni, p. 158. 



n\ Lip expanded or reflexed, at least below. 



b. Parietal wall blackish brown ; lip usually colored ; spiral 

 striation when present rather finer than the longitudinal 

 wrinkling. 



c. Lip and columella purple; surface ashen or brown, 

 usually mottled or dappled. tsto>/ia, p. 150. 



c 1 . Lip and columella blackish ; surface striped and 

 black-varixed on a light ground. mttunnix, p. 153. 

 b l . Parietal callus white or bluish ; spiral striae separated, 

 irregularly cutting the surface wrinkles into long gran- 

 ules ; spire rather attenuated above. 

 c. Base rounded. 



d. Columella folded, lip yellow or pinkish, shell 

 purplish brown with light spots, sometimes 

 yellowish. irroradis, p. 155. 



d 1 . Columella hardly folded ; peristome and pari- 

 etal callus white; yellow, with .some brown 

 streaks and spots. grevi/lei, p. 156. 



c 1 . Base strongly carinated ; lip brown or white, pari- 

 etal callus white. iris, p. 157. 



GKOTP OK P. IOSTOMA. 

 P. IOSTOMA (Sowerby). PI. 49, figs. 17, IS, 19, 20, 21, 22. 



Shell ovate-conic, solid, varying from rather thin to thick. Color 

 (1) pale brownish or pink tinted, almost uniform or faintly mottled 

 with purplish flesh-tint, or (2) creamy or light brown copiously strewn 

 with dark brown or purplish-brown oblong spots, the spire with 

 ragged or /.ig/ag brown streaks, or (.'}) rarely pure white ; frequently 

 marked with a few dark .variceal streaks. Surface dull or somewhat 

 glo~~v, with coarse, usually irregular growth-wrinkles, more or less 

 strongly plicalulate below (he sutures, sometimes with a projecting 

 varix or two on the hist whorl ; a lens often showing close, fine, spiral 

 striation on tin- spire, or in smoother, thin-lipped shells, finely striated 

 spirally throughout. Apex obtuse, the earlier "2\ whorls forming the 

 smooth nepionie. shell. "NVhorls 5[, to <>, convex, the last well rounded. 



Aperture ovate, white within (sometimes showing the external 



