254 OUTLINES OF E VOLUTION AEY BIOLOGY 



IV 



FIG. 109. Feet of Ungulates 

 belonging to the extinct 

 group Litopterna, from 

 Lower Tertiary deposits of 

 Patagonia. (From Smith 

 Woodward's " Vertebrate 

 Palaeontology," after 

 Ameghino.) 



A, B, Theosodon lydekkeri; right fore and hind feet, x J. 



C, Proterotherium intermixtum ; right fore foot, x . 



D, E, Thoatherium crepidatum ; left fore and hind feet, 



