CONCLUSION. 



187 



(5.) In the further reduction of tlie Perissodactyl foot, the fifth digit, 

 bein"- shorter than the remaining three, next left the ground, and 



Figure 162. — Left fore foot of Eporeodon socialis, \farsh. 

 Figure 1 63. — Left hind foot of same. 



Both tigures are one-third natnral size. 



17 n 



Figure 16-1. — Left fore foot of JJippupotanius arnphibius, Linuaius. 

 Figure 1 (55. — Left hind foot of same. 



Both figures are one-eiglilh natural size. 



gradually disappeared. Of the tliree remaining toes, tlie middle, or axial, 

 one was the longest, and retaining its supremacy, as greater strength and 

 speed were required, finally assumed the chief support of the foot, while 



