CHLOROSTOMA. 179 



or smooth ; the periphery is obtusely angular ; and there is a slight 

 prominent carina or angulation on the middle of the upper surface 

 of the whorls ; on some specimens there is a subsutural row of 

 rounded grains; base slightly convex, bearing about 8 concentric 

 crenulated lirse similar to those of the upper surface, but more 

 separated, dotted with white, the interstices microscopically spirally 

 striate ; aperture oblique, outer lip slightly crenulated, or smooth 

 within ; columella short, arcuate, with a heavy white callus above, 

 connecting with a pearly callus which coats the parietal wall ; um- 

 bilicus rather large, deep, its edge formed by a spiral rib which 

 terminates in a tooth at the base of the columella ; immediately below 

 this is a smaller one, and a third denticle is situated at the junc- 

 tion of columella with the base ; basal margin thickened within, 

 smooth. Alt. 12, diam. 16 mill. 



West ladies (A. Ad.\ 



Phorcus semigranosus A. AD., P. Z. S., 1851, p. 157. 



This species may be known by the close, crenulated line, the 

 color which is a little too dark for umber but is more of a bistre 

 shade, the obtuse carina on the middle of the upper surface of each 

 whorl, etc. 



C. QUADRICOSTATUM Wood. PI. 28, fig. 49. 



Shell umbilicate, conical, solid, thick, blackish ; spire conoidal, 

 apex rather blunt, sutures canaliculate ; whorls 6, encircled by 4 

 coarsely tuberculose ribs on the upper surface ; the upper two con- 

 tiguous, sometimes coalescent ; base with 3 or 4 separated smaller 

 beaded ribs, the broad interstices both above and below densely, 

 finely spirally striate; periphery obtusely angular; base nearly flat; 

 aperture oblique, smooth within, columella sinuous, oblique, biden- 

 tate ; umbilicus surrounded by a white callus, bearing inside a strong 

 spiral rib which terminates in a denticle about the middle of the 

 columella. Alt. 23, diam. 25 mill. 



Coast of Chili. 



T. qaadricottatus WOOD, Ind. Test. Suppl., t. 5, f. 16. PHILIPPI, 

 Conchyl. Cab., p. 154, t. 25, f. 6. FISCHER, Coq. Viv , p. 104, t. 31, 

 f. 2. T. torulosus PHIL., Abbild., i, Trochus, t. 2, f. V2.Monodonta 

 catenifem POT. ET MICH., Galerie des Moll., i, t. 29, f. 12, 13 (not T. 

 catemfera Kiener, also a Chlorostoma). 



