10 TROCHUS. 



Section Chlorodiloma Pilsbry. 



Shell like Diloma but rather more conical, less nacreous ; colora- 

 tion, variegated, consisting of fine lines of dark on a lighter ground ; 

 columella generally green ; umbilicus perforate or subperforate. 

 Type, M. crinita Phil. Australasia. 



Section Oxystele Philippi. 



Shell depressed conical, dark or variegated in color ; aperture 

 large, oblique ; columella concave, arcuate, thin-edged, perfectly 

 simple and curved below, above spread over the umbilical area as 

 a rounded, well-defined pad of callus. Type, M. merula Lam. 



S. Africa ; Japan. 



Genus CANTHARIDUS Montfort, 1810. 



Shell ovate-conic or pyramidal imperforate, smooth or spirally 

 sculptured outside, brilliantly iridescent within ; colors generally 

 bright and variegated ; aperture less than half the length of shell, 

 longer than wide, ovate; columella usually more or less folded or 

 toothed near the base. Australasian Seas. 



Subgenus Cantharidus Montfort. 

 Section Cantharidus (restricted.) 



Shell rather thin, ovate-pointed, whorls striated, or smooth ; col- 

 umella rather straight, simple, not toothed. Type, C. iris Chem. 



Section Phasianotrochus Fischer. 



Shell thick, solid, polished, ehmgated ; ovate-pointed ; aperture 

 ovate, longer than broad ; columella arcuate, bearing usually a tooth- 

 like projection in the middle. Type, C. badius Wood. 



Subgenus Bankivia Beck, 1848. 



Shell imperforate, elongated, narrow, conical, thin, but slightly 

 pearly ; aperture small, about one-third the length of shell ; col- 

 umella slightly twisted, subtruncated toward the' base. Type, C. 

 varians Beck. 

 Section Leiopyrga H. & A. Adams. 



Shell perforate, elongated, narrow, somewhat turrited, thin, the 

 whorls convex, rounded or carinated ; aperture oval, small, columel- 

 la arcuate, not truncated at base. Type, C. picturata Ad. 



Subgenus Thalotia Gray, 1840. 

 Shell imperforate, elevated-conical, thick, solid, granulated or 

 s])irally ribbed ; periphery rounded or obtusely angular ; aperture 



