. 



86 THEORY OF THE EARTH. 



In order that the paws may be able to seize the 

 prey, there must be a certain degree of mobility 

 in the toes, and a certain degree of strength in 

 the claws, from which there will result determi- 

 nate forms in all the phalanges, and a correspond- 

 ing distribution of muscles and tendons. The 

 fore-arm, or cubitus, must possess a certain facility 

 of turning, from which there will also result deter- 

 minate forms in the bones of which it is composed. 

 But the bones of the cubitus being articulated to 

 the humerus, a change in the proportions of the 

 former, will necessarily induce a corresponding 

 change in the latter. The shoulder-bones must 

 have a certain degree of firmness in such animals 

 as make use of their fore-legs for seizing, and from 

 this there must also result a certain peculiarity in 

 their form. The play of all these parts will re- 

 quire certain proportions in all their muscles, and 

 the impressions made by these muscles so propor- 

 tioned, will determine still more particularly the 

 forms of the bones. 



It is easy to see that similar conclusions may be 

 drawn with regard to the posterior extremities 

 which contribute to the rapidity of the general 

 motions ; with regard to the composition of the 

 trunk, and the forms of the vertebrae, which exert 

 an influence upon the facility and flexibility of 

 these motions; and, lastly, with regard to the forms 

 of the bones of the nose, of the orbit, and of the 



