80 



ANIMAL LOCOMOTIOK, 



is not adapted for water, and, as a consequence, he requires 

 to abandon it and assume a horizontal one ; he requires, in 

 fact, to throw himself flat upon the water, either upon his 

 side, or upon his dorsal or ventral aspect. This position 

 assimilates him to the quadruped and bird, the fish, and 

 everything that swims ; the trunks of all swimming animals 

 being placed in a prone position. Whenever the horizontal 

 position is assumed, the swimmer can advance in any direc- 

 tion he pleases. His extremities are quite free, and only 

 require to be moved in definite directions to produce definite 

 results. The body can be propelled by the two arms, or the 

 two legs ; or by the right arm and leg, or the left arm and 

 leg ; or by the right arm and left leg, or the left arm and 

 right leg. Most progress is made when the two arms and 

 the two legs are employed. An expert ewimmer can do 

 whatever he chooses in water. Thus he can throw himself 

 upon his back, and by extending his arms obliquely above his 

 head until they are in the same plane with his body, can 

 float without any exertion whatever; or, maintaining the 

 floating position, he can fold his arms upon his chest and by 

 alternately flexing and extending his lower extremities, can 

 propel himself with ease and at considerable speed ; or, keeping 

 his legs in the extended position and motionless, he can pro- 

 pel himself by keeping his arms close to his body, and causing 

 his hands to work like sculls, so as to make figure-of-8 loops 

 in the water. This motion greatly resembles that made by 

 the swimming wings of the penguin. It is most effective 

 when the hands are turned slightly upwards, and a greater or 

 less backward thrust given each time the hands reciprocate. 

 The progress made at first is slow, but latterly very rapid, 

 the rapidity increasing according to the momentum acquired. 

 The swimmer, in addition to the foregoing methods, can 

 throw himself upon his face, and by alternately flexing and ex- 

 tending his arms and legs, can float and propel himself for long 

 periods with perfect safety and with comparatively little exer- 

 tion. He can also assume the vertical position, and by remain- 

 ing perfectly motionless, ox by treading the water with his 

 feet, can prevent himself from sinking ; nay more, he can turn 

 a somersault in the water either in a forward or backward 



