FLYING-FISH. 



133 



The Half-beak, Hemirhamphus, 450, of most tropical seas, 

 instead of having the upper and lower jaws both prolonged to form 

 a beak, has only the lower jaw long. It feeds mostly on green 

 seaweeds. 



The Flying-fishes, Exoccetus (452, and fig. 62) do not have the 

 jaws prolonged ; the teeth are feeble and uniform, the pectoral fins, 



Half- 

 beak. 



Flying 

 fish. 



^^^^^^^^^ 



Fig. 62. — A Flying-fish, Exoccetus spilopterus. 



and in some species the pelvic fins also, and the lower lobe of the 

 tail are greatly enlarged. They live in shoals in tropical and 

 sub-tropical seas and are pursued by large fishes such as the Tunny 

 and Albacore. Exoccetus volitans is a small species, with short 

 pelvic fins, sometimes taken off the British coast j the largest 

 Flying-fish is the Californian species, which attains a length of 

 eighteen inches. 



Although called Flying-fish, the species of Exoccetus do not 

 really fly. They leave the water with great velocity by a powerful 

 movement of the tail, and then scud through the air until they 

 reach the water again, when another rapid movement of the tail 

 may start them afresh through the air without the whole of the 

 body entering the water. The pectoral fins are not moved as 

 organs of true flight. They may vibrate and quiver somewhat, 

 but the whole motive power is supplied by the strong tail. The 

 movements of the pectoral fins are in no way comparable with 

 these of the wing3 of a bird ; the fins act as a parachute only. 



The Sand-eels or Launces (family Ammodytidse) are small, Sand-eel. 

 silvery fishes swimming in shoals near the shore, and remarkable 

 for the manner in which by their sharp pointed snout they bury 



