X \- 1 1 1 , ] UA'CULA TA . 303 



inferior articular surface is very prominent. In all the 

 Perissodactyles there is a strongly marked third trochanter 

 (/'), in the form of a compressed ridge curving forwards. 

 This is entirely absent in all the known Artiodactyles. 



Fic. no. — Anterior aspect of right femur ot Rhinoceros {Rhinoceros indicus), \. 

 k head ; t great trochanter; t third trochanter. 



The fibula is subject to great variations among the 

 different members of the order. In the Rhinoceros, Tapir, 

 Pig, and Hippopotamus it is complete and distinct, though 

 slender in proportion to the tibia. In the Horse a mere 

 styliform rudiment of the upper end is present. 



In all Pecora and Tylopoda, a small distinct bone, having 

 a very definite form, articulating with the lower end of the 

 tibia, and forming the external malleolus, appears to 

 represent the distal extremity of the fibula (see Fig. iti). 

 There is occasionally in addition a slender styliform rudi- 



