MODULUS. 261 



M. LENTicuLARis (Chemii.), Auct. PI. 48, figs. 91, 92. 



Flattened above, with distant radiating ribs, periphery acutely 

 carinated, defined by a rib, convex below, everywhere minutely 

 spirally corded, spire-whorls often exserted sufficiently to show the 

 carina ; whitish, articulated with reddish chestnut. 



Diara. 15-18 mill. 



West Indies. 



Distinguished at once from the preceding species by the flatter 

 top, and stronger carina, It is M. modulus, Linn., and M. filosus, 

 Helbling. 



M. DiscuLus, Phil. PI. 48, figs. 98, 94; PI. 49, fig. 95. 



Spire conical, more elevated than in the preceding species, the 

 distant radiating ribs forming by their terminations a series of tu- 

 bercles on the sharply carinated periphery; base flatly convex, with 

 close, subnodulous spiral cords ; white, tessellated with chestnut at 

 the suture and periphery, aperture violaceous. Diam. 10 mill. 



Acajndco, Mazatlan. 



M. dorsuosus, Gould, (fig. 95), and perhaps M. I'widus, Phil., are 

 synonyms. 



M. CERODES, A. Ad. PI. 49, figs. 96, 97. 



Depressed, distantly radiately ribbed, the ribs projecting at the 

 carinate periphery, where they are cut by two or three impressed 

 spiral lines, base with several revolving riblets, two of which are 

 larger and tuberculate. Diam. 12 mill. 



Mozambique (Cuming), Gulf of California (Carpenter.) 



The two series of tubercles often unite into one. 



M. UNiDENs (Lister), Auct. PI. 49, figs. 98-100. 



Conical, whorls flattened, obsoletely, radiately, distantly ribbed 

 above the angulated periphery, everywhere closely spirally corded ; 

 white, the cords minutely punctate with reddish chestnut. 



Diam. 15 mill. 



Wext Indies, West Coast of N. America, Philippines, etc. 



The synonymy includes 31. angulatus, C. B. Ad., M. Sayi (Nut- 

 tall), A. Ad., M. irocMformis, Eyd. et Soul. (fig. 100), M. perlatus, 

 Dillw., M. Carchedonicus, Lam., M. catennlatus, Phil. 



M. MoRELETi, Fischer. PI. 49, figs. 1, 2. 



Narrowly subperforate, rather thick, spirally lirate, carinate, the 

 body whorl bicarinate ; lip thick, sub-bilabiate ; whitish, tlie upper 



