106 PHYLLONOTUS. 



eventually they will be found to merge one into the other, when 

 numerous localities between their respective stations shall be ex 

 amined. If my surmise should prove correct, the species must 

 bear the name of radix. 



M. PRiNCEPS, Brod. PL 28, fig. 250. 



Pyriform, spire rather longer than in M. nitidus and with a 

 shoulder on the whorls ; varices five to eight, raised into distant 

 spines, of which a single series on the shoulder of the body, and 

 continuing on the spire is much more prominent. Whitish, ribs 

 and spines sometimes chestnut brown. 



Length, 2-5 to 4 inches. 



W. Coast Central Am- 



A beautiful species ; the operculum is not fimbriated like that 

 of M. 7-adix. 



M. TURBiNATUS, Lam. PI. 28, figs. 252, 251. 



Ovate-p3a-iform, somewhat angulated on the periphery and 

 flattened above it; with revolving raised ribs and six to eight 

 varices ; the latter tuberculate or shortly spinous on the angles of 

 the whorls. Whitish or yellowish, with brown bands, most prom- 

 inent on the varices; aperture white or pink, columella bright 

 pink. Length, 2*5 inches. 



Senegambia . 



The M.turhinatusfigwYQd by Sowerby (Thes. Conch., fig. 185), 

 is M. rosarium^ Chemn. M. spinosus, A. Ad., (fig. 257), is a 

 synonym of turbinatus, being merely a thickened variety. The 

 same form has been described by M. Tapparone-Canefri from sub- 

 fossil specimens under the name of M. KilMerianus. 



M. Beckii, Phil. PI. 28, fig. 249. 



Very like M. turbinatus, but wants the tuberculations on the 

 varices, whilst it is heavier and more spinous. Light brown ex- 

 ternally, pink within the aperture. Length, 3 inches. 



Hab. unknown. 



May be a form of M. turbinatus and also possesses characters 

 in common with M. spinicostata. 



