16 
SHELL GALLERY. 
Case 38. 
voracious. This is one of the groups of shells that have continued 
to exist from Palseozoic times. 
The " Violet Snails " (Ianthinidce) are found floating about in 
every ocean, excepting in cold regions, with the spire of the shell 
downwards, and the bottom, being more exposed to the action of 
light, is more deeply tinted than the upper part. They feed upon 
Fig. 10. 
Cyprssa leucodon. Case 32. 
Jelly-fish, and construct a gelatinous raft, filled with air-bubbles, 
beneath which the females attach their eggs. 
