CHLOROSTOMA. 179 



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

 prominent carina or angulation on the middle of the upper sui-face 

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

 rounded grains; base slightly convex, bearing about 8 concentric 

 crenulated lirre 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 thii'd denticle is situated at the junc- 

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

 smooth. Alt. 12, diam. 16 mill. 



West Indies {A. Ad.), 



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



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

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

 shade, the obtuse cai'ina 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 uppeT 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. qiiadricostatus Wood, Ind. Test. Suppl., t. 5, f 1(3.^ — Phtlippi, 

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

 i\ 2. — T. torulosus Phil., Abbild., i, Trochus, t. 2, f 12. — Monododa 

 catenifera FoT. et Mich., Galerie des Moll., i, t. 29, f. 12, 13 (not 7\ 

 catenifera Kiener, also a Chlorostoma). 



