566 THE OCEAN WORLD. 
having left their native element ; for on watching them I have often 
seen them fall much below the elevation at which they first rose from 
the water ; nor have I ever in any instance seen them rise from the 
height to which they first sprang, for I conceive the elevation they 
take depends on the power of the first spring. 
Fig. 372.—The Flying-fish (E. exiliens); 
The most common species is Z. volitans. Its brilliant colouring 
would seem designed to point it out to its enemies, against whom it 
is totally defenceless. A dazzling silvery splendour pervades its 
surface. The summit of its head, its back, and its sides, are of azure 
blue ; this blue becomes spotted upon the dorsal fin, the pectoral fin, 
and the tail. This fish is the common prey of the sea-birds and 
the more voracious fishes, such as the shark ; its enemies abound in 
the air and water. If it succeeds in escaping the Charybdis of the 
