160 THE OCEAN WORLD, 
it is opaline, and occasionally it is of a bright blue or pale rose 
colour. In certain species the central parts are of a lively red, blue, 
or violet colour, while the rest of the body is of a diaphanous hue. 
This diaphanous tissue, often decked in the finest tints, is so fragile, 
that when abandoned: by the wave on the beach, it melts and disap- 
pears without leaving a trace of its having existed, so to speak. 
Fig. 53.—Aurelia aurita (Lamarck). Cynea aurita (Cuvier). One-third natural size. 
Nevertheless, these fragile creatures, these living soap-bubbles, 
make long voyages on the surface of the sea. Whilst the sun’s rays 
suffice to dissipate and even annihilate their vaporous substance 
when cast on some inhospitable beach, they abandon themselves 
without fear during their entire life to the agitated waves. The 
whales which haunt round the Hebrides are chiefly nourished by 
Medusz which have been transported by the waves in innumerable 
