XIX.] 



UNGULA TA. 



3'9 



tyle foot of the Rhinoceros and the monodactyle foot of 

 the Horse are met with in extinct species of the Perisso- 



dactyla. 



Fig. 118. — Dorsal surface of right tarsus 

 of Rhinoceros (Rhinoceros sumatren- 

 sis, \. 



Fig. 119— Dorsal surface of right tarsus 

 of Horse [Egnus caballus), \. 



In the Artiodactyla the third and fourth digits are nearly 

 equally developed, and their ungual phalanges are flattened 

 >n their contiguous sides, so that together they constitute a 

 rmmetrical form. The second and fifth toes, when present, 

 re also equal, but smaller than the others. A line drawn 

 lough the centre of the foot has on its tibial side the 

 lird digit and metatarsal, the external cuneiform, the 

 ivicular, and half the astragalus ; and on its fibular side 

 le fourth digit and metatarsal, the cuboid and the other 

 ilf of the astragalus. The distal articular surface of the 



