188 SI STRUM. 



R. MUTicA. Lam. Fl. 58, fig. -246. 



Brownish black; lip margined with dark chocolate, teeth white-, 

 columella and interior white or blnish. Ijength, -fio inch. 



Mozamhiqve ; Mauritius. 



Yerv distinct in form and coloring. 



R. DUMOSA, Conr. PI. ;")8, figs. 245, 243, 241». 



Yellowish externally; pnri)le, A-iolet or light cliocolate within. 



Leneth •fi5--8 inch Sandwich Isles ; Marquesas. 



There can be no doubt of" the identity' of Reeve's R. porphy- 

 rostoma Avith this s[)ecies, which is well fignred in connection 

 with the original description, and has nine years' priority. 



Mvrex Lieaardi, Crosse (tig. 249), from Mauritius has been 

 referred to R. fiacellum, Chemn., by Nevill (Jour. Asiatic Soc, 

 83, 1875) ; 1 am inclined to consider it very close to, if not iden- 

 tical with B. damoi^a. 



R. losTOMa, Reeve. PI. 58, lig. 248. 



The nodules of the revolving ribs are tinged with black; the 

 violet aperture is not contracted ; otherwise this species is closely 

 related to B. dmnosa. Length. 1 inch. 



Hab. unknown. 

 R. CANCELLATA, Quoy. PI. 58, figs. 242, 250. 



Externally whitish or grayish ; aperture yellowish or orange^ 

 brown. Length, •75-1-25 inches. Philippines to Sandwich Isles. 



Readily distinguished by the dee) spitted, square interstices 

 formed by the crossing of the longitudinal and revohnng ribs. 



R. nscELLUM, Chemn. PI. 58, figs. 251-257. 



White, yellowish or chocolate, the longitudinal ribs and the 

 pit-like depressions (defined by the crossing of the revolving ribs) 

 frequentlj' tinged with brownish or blackish ; violaceous within 

 the aperture. Length, -6-1 inch. Philippines to Sandwich Isles. 



The spire is much shorter and the whorls more shouldered 

 than in B. cancellata. The color of the aperture is different. 

 There are fewer longitudinal ribs, and the revolving ribs are com- 

 pound, composed of a bundle of smaller ones. The species has 

 been confounded especially with B. undata (= margariticola) 

 by some of the monographers, and considerable confusion of 

 synonymy has thereby resulted. 



