150 PORPHYROBAPHE. 



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

 mella and parietal callus pale ; profusely mottled, and with 

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



a 1 . 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. iostoma, p. 150. 



c 1 . Lip and columella blackish ; surface striped and 

 black-varixed on a light ground. saturnus, 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. irroratus, p. 155. 



d l . Columella hardly folded ; peristome and pari- 

 etal callus white ; yellow, with some brown 

 streaks and spots. grevillei, p. 156. 



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

 etal callus white. tm, p. 157. 



GROUP OF P. IOSTOMA. 



P. IOSTOMA (Sowerby). PI. 49, figs. 17, 18, 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 zigzag brown streaks, or (3) rarely pure white ; frequently 

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

 glossy, with coarse, usually irregular growth-wrinkles, more or less 

 strongly plicatulate below the sutures, sometimes with a projecting 

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

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

 spirally throughout. Apex obtuse, the earlier 2-J whorls forming the 

 smooth nepionic shell. Whorls 5^ to 6, convex, the last well rounded. 



Aperture ovate, white within (sometimes showing the external 



