UNIVALVE MOLLUSC A. 



453 



wath flexual lines of a yello^^^sh brown, with two brown bands, 

 combined with the fine yellowish tint of gold colour within. Oliva 

 porphyria, from the Brazil coast (Fig. 276), presents lines of a reddish 

 brown, regularly interlaced with spotted large brown marks, upon a 

 flesh-coloured ground. Oliva irisaiis (Fig. 277) is painted in zigzag 

 lines, close and brown, edged \A\\\ orange-yellow, and with two zones 

 of darker brown, and reticulated. Oliva Peruviana (Fig. 278) is 

 farrowed with regularly spaced bands. 



In the genus Cassis the shell is oval, convex, and the spire is 



Fig. 275. 



Oliva erythrostoma 



(Lamarck). 



not of considerable height. The longitudinal opening is narrow, 

 terminating in front in a short channel, which becomes suddenly 

 erect towards the back of the shell, as in Cassis gJauca (Fig. 279), a 

 fine shell from the Moluccas. The columella is folded or toothed 

 transversely, as in Cassis ri/fa, Fig. 280 ; the right edge thick, 

 furnished with a sort of pad externally, and dentate within. This 

 shell is from the Indian Ocean, and is of a fine purple colour, varied 

 with black above ; the edges of the opening being of a coral red 

 colour, the teeth alone being white. 



The head of the animal is large and thick, furnished with two 

 conical elongated tentacles, at the base of which are the eyes. The 

 mantle is ranged outside the shell, falling back upon the edges of the 

 opening, and terminating at its anterior extremity in a long cylindrical 

 channel, cloven in front, and passing by a hollow at the base into the 



