TROCHUS. 11 



small, ovate, outer lip thick, crenulated within ; columella toothed 

 at base, subtruncated. Type, C. conicua Gray. 



Section ODONTOTROCHUS Fischer. 



Shell conical, elevated; periphery acutely carinated ; columella 

 toothed below, truncated. Type, C. chlorostomus Mke. 



Genus GAZA Watson, 1878. 



Shell trochiform, nacreous both on the surface and throughout ; 

 delicately sculptured, witli a reversed lip thickened internally by a 

 nacreous callus; the pillar twisted direct, in front angulated and 

 pointed, behind entirely parted from the lip, and in the umbilical 

 region spread out in a nacreous pad. ( Watson) Type, G. dsedala 

 Watson. Fiji Is. 



Submenus MICROGAZA Dall, 1881. 



Shell flattened, rotelliform, resembling a Gaza without reflected 

 lip or umbilical callus, brilliantly nacreous when fresh, and having 

 a distinctly scalariform umbilicus. (Dall) Type, M. rotelia Dall. 



Barbados. 



(Jcnus CALLOGAZA Dall, 1881. 



Shell resembling Gaza Watson, but with the umbilical pad re- 

 flected only partly over the umbilicus ; the pillar straight, passing 

 without notch or mucronation into the reflected basal margin of the 

 aperture ; nacreous layer in this shell covered with a thin non- 

 nacreous layer, which appears to be covered by a delicate epider- 

 mis. (Dall) Type, C. superba Dall. 



Genus BEMBIX Watson, 1878. 



Shell conical, high, carinated, tumid on the base, umbilicated, 

 thin, nacreous, covered with a thin membranaceous epidermis. ( Wat- 

 sou) Type, B. ajola. Japan. 



Genus CHLOROSTOMA Swainson, 1840. 



Shell conical, umbilicate or imperforate, solid ; spire elevated or 

 depressed ; aperture oblique, subrhomboidal, the outer lip smooth 

 within ; columella arcuate, above continued in a callus over or half- 

 way around the umbilicus, which when open shows one or more 

 spiral ribs inside ; base of columella with two or more denticles. 

 Type, C. argyrostomum Gin el. 



Chinese and Japanese Seas, W. Coast America, West Indies. 



