FORM AND LOCOMOTION 



31 



American sea-anglers, is another fish famed for its leaping 

 powers, and its indulgence in this habit makes it necessary to 

 employ some skill and perseverance in its capture (Fig. 13B). 

 As Dr. Gill remarks: "Its frequent leaps into the air . . . seem 

 to be mostly in sportive manifestation of its intense vitality, and 

 not for food or entirely from fear." Opinions differ as to the 

 height to which these fishes are able to jump, but it is generally 

 agreed that seven or eight feet probably represents the Tarpon's 



Fig. 13. FISHES THAT LEAP. 



A. Devil-fish {Manta birostris), X about -V ; b. Tarpon (Megalops atlanticus), 

 X about ^V ; c. Salmon {Salmo salar), X yV ; D- Grey Mullet (Miigil sp.) X yV- 



limit, while the Salmon is only able to better this by one or 

 two feet. How are the jumps accomplished? Generally by 

 the fish swimming rapidly upwards through the surface of the 

 water into the air, giving a sharp flick with its tail as it leaves 

 the liquid medium. All the active propulsion is provided by 

 the muscular actions of the body while in the water, but the 

 passing into the relatively less dense air accelerates the speed 

 considerably and makes powerful leaps possible with a fairly 

 slight muscular effort. Both Tarpon and Salmon hold the 

 body in a curve while out of the water, and naturally fall to 



