Of the Ovulidæ, the most curious is the “Weaver’s-shuttle” (Radius volva), in which the shell is peculiarly beaked at both ends. It is found living on barked corals (Gorgoniidæ), and some of the smaller species exhibit differences of coloration, resembling the tints of the Gorgonias upon which they are found.
Cases 36–37.
The Naticas are mostly blind, and have a very large foot, suitable for burrowing in the sand when in quest of bivalves. They are very voracious. This is one of the groups of shells that have continued to exist from Palæozoic times.
Case 38.
The “Violet Snails” (Ianthinidæ) 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 Jelly-fish, and construct a gelatinous raft, filled with air-bubbles, beneath which the females attach their eggs.
Fig. 10.
Cypræa leucodon. Case 32.
Cases 38–41.
The Melaniidæ are freshwater Snails which abound in most tropical and subtropical countries; about 1000 species are known. They are mostly of dark colours, and are fond of muddy places.
Cases 42–43.