106 GIANT FISHES 



the snout is pointed. Further, in the young stage the lower 

 jaw is drawn out just like that of the adult Half-beak, and 

 shortens only as the fish grows up. Among the other Flying- 

 fishes two main types may be recognized : the so-called 

 " two winged " Flying-fishes, in which only the pectoral fins 

 are enlarged, and the " four-winged " Flying-fishes, in which 

 the pelvic fins are also much larger than usual and, like the 

 pectorals, play an important part as organs of flight. 



The actual mode of flying must be briefly considered, since 

 this has for many years been the subject of acute controversy. 

 The flights are made primarily as a means of escape from 

 enemies, or when the fish is alarmed by an approaching ship, 

 but at times they appear to be taken for no apparent reason. 

 It must be clearly understood that the flight is quite unlike 

 that of a bird or bat, since there is no actual movement of 

 the " wings " (pectoral fins), which are held rigid, and act 

 after the manner of the planes of a " glider ". 



In order to demonstrate the nature of the flight, the different 

 phases in a typical flight of a fish of the " four-winged " type 

 (the Flying-fish par excellence) may be described (see Fig. 37). 

 The fish first swims rapidly towards the surface, with both 

 its pectoral and its pelvic fins folded against the body. It 

 next breaks the surface of the sea, and the pectoral fins are 

 spread out to support the front part of the body, whilst 

 the pelvic fins remain folded. The fish then gains power for 

 the flight by " taxi-ing " or skimming along the surface, the 

 propulsive power fc r this movement being supplied by violent, 

 side-to-side movements of the tail, the long and strong lower 

 lobe of the caudal fin being kept in the water. During this 

 " taxi " movement, which is comparable to that of an aeroplane 

 just before it leaves the ground, the whole body of the fish 

 shakes, and the tips of the pectoral fins vibrate, giving a false 

 impression of a flapping of the " wings ". At the end of it 

 the fish is shot into the air at a speed which has been estimated 

 at not less than 35 miles per hour. The pelvic fins are now 

 spread out, thus lifting the tail from the water, and both pairs 

 of fins are held out rigid and motionless during the flight. 



The length of time occupied by each flight rarely exceeds 

 30 seconds, and in the majority of cases is much shorter. 

 During a flight the fish may cover as much as two or three 



