CASSIDARIA. CASSIS. 87 



the interior of the lip is pink. ^S*. Uneatus has 

 dark lines round the shell. S. vittatus has a 

 very long spire ; the colour is tawny, girded with 

 white : you may easily meet with this species. 



" The family Purpurifera is composed of 

 genera taken chiefly from the large Linnc^ean 

 genus Bucc'miim. 



" It is thus divided : 



" First, the genera with the canal ascending, 

 or turned towards the back of the shell — 



Cassidaria, i 



^ . \ BucciJium^ helmets. 



" Cassidaria is not a very common genus ; but 

 the helmets, Cassis, are both numerous and plen- 

 tiful in most collections. The straight aperture 

 slightly reminds you of a CyprcEa perhaps, but the 

 short canal, abruptly turned back, is a clear dis- 

 tinction ; the right-margin generally toothed ; the 

 columella folded, or wrinkled, transversely. 



" C. corniita, C, Jlummea, C. areola and 

 vibe/v, are all well-known species, C. cornuta 

 has large tubercles like horns round the tip of the 

 shell. C. areola is marked with chequers. C. 

 riifus, from the Moluccas, is a fine shell, with a 

 deeply coloured red aperture. 



" In the next division the canal is oblique, and 

 directed backwards. 



