MOLLUSCS 89 



only as chance visitors and their delicate shells seldom 

 survive contact with the beach. These unique sea snails 

 never willingly meet with any solid support, but live 

 floating lives in mid-ocean. Both shell and occupant 

 are of a lovely violet blue. The eggs are laid in spindle- 

 shaped capsules attached to the undersurface of a glistening 

 fairy-like raft composed of a viscid secretion filled with 

 air bubbles and varying from a few inches to a foot in 

 length according to the species. Violet Snails devour 

 jellyfish and when molested cloud the water with a quantity 

 of violet fluid. 



The allied Bulima have long, white, highly polished 

 shells and the animals are of interest as being parasitic 

 upon sea urchins and other echinoderms. Several forms 

 are native to our waters. 



The Carrier Shells instead of attaching themselves 

 contrive to affix stones and other shells to their own edifices, 

 the result being an effective if cumbersome camouflage. 



The Wind Shells (Strombus) are familiar ornaments of 

 the seafarer's home and in Victorian days were favourite 

 garden ornaments. The huge S trombus gigas of the West 

 Indies is in demand for the manufacture of porcelain, 

 over 300,000 being imported for that purpose to Liverpool 

 every year. The Wind Shells, like their nearest British 

 relative the Pelican's Foot Shell (Aporrhais pes-pelicani), 

 have the foot prolonged into a stout club by means of 

 which the animal progresses in a series of grotesque hops. 



Both the Fountain Shells and their allies the Helmet 

 Shells are of interest in that the shell is built up of a differ- 

 ently coloured layer. 



The related Glass Shells (Carinaria) have disproportion- 



