54 



BOOK OF SPECIES. 



oblique; the callus red, sub-divided, partly co- 

 vering the umbilicus ; diam. 2. 



N. ALBUMEN. Sub-orbicular, convex, de- 

 pressed, thickish, smooth, reddish fulvous, flat 

 beneath, milky ; spire very blunt, and oblique ; 

 the somewhat heart-shaped callus on the inner 

 lip partly concealing the umbilicus; diam. 1|. 

 W. 35. 17. 



N. MAMMILLA. Oval - vcutricosc, flattish 

 convex, thickish, brilliant white ; spire rather 

 prominent; the callus of the inner lip of the 

 adult entirely covering the umbilicus; diam. IJ. 

 W. 35. 19. 



N. MELANOSTOMA. Oval-couvcx, depressed, 

 ventricose, thin, fulvous, whitish, with a broad 



