CHLOROSTOMA. 185 



above, and these are articulated with white ; the periphery is obtusely 

 subangular, and bears two more conspicuous lirje articulated with 

 white, between which there are several lirulse ; the base is rather 

 flattened, concave in the middle around the umbilicus, and white, 

 with about 6 rather strong concentric Yirse articulated with dark 

 spots ; the outer part of the base is encircled by a zone of very 

 minute spiral ribs ; aperture oblique, rounded-quadrate ; columella 

 sinuous, arcuate ; umbilicus white within, bordered by a strong 

 spiral rib which terminates in a tooth at the base of the columella, 

 beneath which is another smaller similar denticle. 

 Alt. 7, diam. 8 mill. 



C. IMPRESSUM Jonas. PI. 63, figs. 8, 9. 



Shell narrowly and profoundly perforate, rather thick, conoid, 

 dull cinereous, ornamented with castaneous radiating flammules ; 

 whorls 6, rather convex, spirally finely lirate, the lirfe 7 to 8 on the 

 penultimate whorl, 5 on the preceding ; last whorl rounded, com- 

 pressed below the suture above, somewhat convex beneath, and 

 provided with about 10 concentric lir?e; aperture slightly dilated, 

 ovate, the lip plicatulate within ; columella thin in the middle, 

 arcuate, concave, bearing 2 or 3 tubercles below ; columellar callus 

 thick, green, slightly impinging upon the umbilicus- 

 Alt. 13, diam. 13 mill. (Fischer.) 



W. coast S. America (J) ; Mazatlan (?). 

 Trochus impressus Jonas, in Philippi, Conchyl Cab., p. 318, t. 

 45, f. 6.— Fischer, Coq. Viv., p. 252, t. 85, f 2.— T. corviis Phil., 

 Zeitschr.f. MaL, 1849, p. 152. (Error). 



C. SCALARE Anton. PI. 29, figs. 70-73. 



Shell broadly, deeply umbilicated, conical, white, nearly uni- 

 colored, (1) articulated on the ribs with reddish or olive-brown 

 dots, (2) tinged with pinkish or olive all over and dotted with a 

 darker self-color on the ribs, (3) with broad radiating pinkish, 

 olivaceous or yellowish maculations above, maculated or speckled 

 on the base. Spire generally elevated, sometimes scalariform, 

 pointed, conical, the apex acute ; sutures deeply marked ; whorls 6 

 to 8, quite convex, obliquely striate, spirally lirate, the lir?e generally 

 rather low, but sometimss elevated, cord-like, and numbering from 

 7 to 12 on the penultimate whorl. The lirai are rather irregularly, 

 slightly crenulated ; they are unequal in size, one or two about the 

 middle of the upper surface generally being larger, causing a flight 



