LOCOMOTION. 



79 



are developed, this intimate relation between the muscles 

 and the vertebras diminish- 

 es. The muscles are un- 

 equally distributed and are 

 concentrated about the 

 limbs, where the greatest 

 amount of muscular force 

 is required. For this rea- 

 son, the largest masses of 

 flesh in the higher verte- 

 brates are found about the 

 shoulders and hips ; while 

 in fishes they are concen- 

 trated about the base of the Fi gt 30. 

 tail, which is the part principally employed in locomotion. 



SECTION II. 



OF LOCOMOTION. 



163. One of the most curious and important applications 

 of this apparatus of bones and muscles is for LOCOMO- 

 TION. By this is understood the movement which an animal 

 makes in passing from place to place, in the pursuit of pleas- 

 ure, sustenance, or safety, in distinction from those motions 

 which are performed equally well while stationary, such as 

 the acts of respiration, mastication, &c. 



164. The means which nature has brought into action to 

 effect locomotion under all the various circumstances in 

 which animals are placed, are very diversified ; and the 

 study of their adaptation to the necessities of animals is highly 

 interesting in a mechanical, as well as in a zoological point 

 of view. Two general plans may be noticed, under which 

 these varieties may be arranged. Either the whole body is 



