Ml 



LOCOMOTION OF ANIMALS. 



LOCOMOTION OF ANIMAIA 



HI 



to support the bead U least in nun, and greatest in the onuig-outan. 

 Again, w see that the proportion* between the length of the arms 

 nJ ten we different in each ; the arm* are longMt ID proportion to 

 the height in the orang, shorter in the chimpanzee, and shortest in 

 man. The leg* are longest in man, lev in the orang, and least in the 

 rtiimnenmi In the orang we observe that the arms nearly reach the 



sole U much narrower and turns inwards, and the outer margin of the 

 foot only presses the ground. 



In man the heel projects a considerable distance behind the axis of 

 motion in the ankle-joint, and acts as a powerful lever in raising the 

 weight of the body on the toes, whereas the bone of the heel U shorter 

 in the chimpanzee, and shortest in the orang ; also in consequence of 



Flf . IS. Chlmpantet. 



Fig. 27 Man. 

 [Skeleton* of Man and Monkey*.] 



Fig. 19. Orang.OuUn. 



ground in Handing; also that in man the spine has three natural 

 curves, but in the other two. there U but one, the consequence of 

 which u, that the head is thrown forwards in front of the vertical 

 line x'r, and the heads of both orang and chimpanzee are supported 

 n the erect position at a mechanical disadvantage, proportional to the 



r 



the inward direction of the soles of the feet in the latter animal, the 

 muscles act on the heel with less effect than in man ; added to which 

 the muscles which raino the body on the foot are much smaller and 

 weaker than in man. But the greatest peculiarity in the hinder 

 extremities of the chimpanzee and orang-outan is, that the inner toe of 



Fi. II. Kknll of Oranr-Outan. 



Fl(t. JO. Skull of Man. 

 -Kiii: of Man and Monkej-n.] 



Fig. 31. Skull of Chimpanzee. 



line x i (Jig*. 28 and 89). Bat one of the greatest peculiarities existing 

 between nan and the other two animals i in the structure of the i 

 fewC In man the entire sole of the foot U either in contact with the 

 rro'ind. or. owing to iu arched figure, the weight of the whole body 

 i* equally distributed orer it ; but in the chimpanzee and orang the 



the foot is attached in an oblique manner, so as to move, like a 

 thumb, in a direction cxcentric to that of the other toes; whereby the 

 foot in these animals answers the double purpose of a foot and a 

 hand. In the performance of the latter function, the inversion of the 

 sole of the foot, which obstructs plantigrade movement, tends to 



