1.86 SISTKUM. 



R. TUBERCULATUS, Blainv. PL 57, figs. 218, 220. 



Very variable in outline, some specimens being much shoul- 

 dered, with short spire, others ovate with longer spire. Closely 

 allied at first sight to R. morus but dark olive-brown, the tuber- 

 cles darker or black, and surface closely covered with revolving 

 striae instead of the single small rib between each row of tuber- 

 cles as in E. morus. The aperture is dark brown or black, the 

 teeth and columella partially white. Length, *75-l inch. 



Japan; Philippines to Sandwich Isles. 



The external resemblance of this species to Purpura musiva, 

 Kiener, is very great ; the genuine purpuroid aperture of the 

 latter will serve to distinguish them. 



The animal is described by Gould in the Mollusca of Wilkes' 

 Exped. as being deep grass-green ; with the mantle, locomotive 

 disk and tentacles light sea-green finely dotted with white. 



R. ANAXERES, Duclos. PI. 51, fig. 219. 



The coloration is the reverse of that of R. tuberculatux ; that 

 is, the shell is dark and the nodules light frequently nearly 

 white. Length, -4--5 inch. 



Natal; Solomon" s Isles ; Australia; Paumotus. 



Is possibly not adult, and is related in sculpture to R. morux, 

 but otherwise more closely to R. tuberculatu*. 



R. MARGINATRA, Blainv. PI. 57, figs. 221, 222, 225-229. 



Shell very variable in outline, cancellated by revolving and 

 longitudinal ribs, by which the surface is broken up into tuber- 

 cles ; most prominent as revolving series and usually ineisely cut 

 by revolving stride which, in the interstices of the nodular series 

 become scabrous. Brownish, the nodules usually darker. Aper- 

 ture bluish within, with revolving raised chocolate lines which 

 terminate in four or five white or fulvous tubercles upon the 

 thickened lip ; lip and columella stained with chocolate. 



Length, '75-1 inch. Australia; Central Polynesia. 



The type (fig. 225) is a young shell; tlie adult \sPurpura 

 marginalbum , Blainv. (figs. 221, 226). I cannot distinguish P. 

 cancellata, Kiener (fig. 227) nor Ricimda fus<-a, Kiister (fig. 222). 

 Pease acknowledges the difficulty of separating his Sistrum 

 affine (fig. 228). and von Martens has already considered it a 



