AURIS. 99 



Key to species and varieties of Auris. 



I. Parietal ivall and lip bearing an erect callous flange, 



a. Body-whorl with high, long oblique ridges separated by 



concave intervals, 

 b. Peristome white and yellow ; columella white, 



bilabiata. 

 bb. Peristome black and yellow ; columella black, 



v. melanostoma. 



aa. Ribs on body-whorl shorter, subobsolete ; form more 

 obese. 



b. Peristome and columella light, egregia. 



bb. Peristome and columella black, v. nigrilabris. 



II. No flange on parietal wall ; outer lip flattened or convex, 



a. Lip, columella and interior of mouth very dark ; a basal 



notch ; dark spots between ribs on spire, 

 b. Ground color white ; flange within outer lip long ; 

 a tooth at base of columella melastoma. 



bb. Ground color fleshy ; flange short, basal ; no tooth 

 on columella v. brachyplax. 



aa. Interior of aperture and the lip white or partly white, 

 b. Columella rather straight ; intervals between ribs 

 on spire white or gray ; surface not distinctly and 

 evenly granulate. 



c. A notch at base of columella ; columella and 

 lip white, golden-brown toward outer edge, 



chrysostoma. 



cc. No notch ; columella and flange on lip black, 



v. swainsoni. 



ccc. No notch ; columella and lip white ; sculp- 

 ture peculiar, bernardii. 

 bb. Columella twisted ; intervals between ribs on spire 

 dark ; surface very distinctly, evenly granulate, 



illheocola. 



A. BILABIATA Broderip & Sowerby. PL 39, figs. 10, 11, 12, 13. 



Shell perforate, ovate-conic, solid, opaque and calcareous. White 

 or pink, generally showing two dark clouds behind the lip, and 

 often irregularly spotted with brown on the body- whorl. Sculptured 

 with prominent obliquely descending ridges, generally seven to nine 

 on last whorl, and not extending to suture above, more or less obso- 



