HISTORY OF THE ARTIODACTYLA 



383 



5. ^AgriochoeridcB. \ Agriochoerids 



This family, one of the strangest and most aberrant of 

 ungulate groups, was very closely allied to the foreodonts and 

 by many authorities is included in the same family. The his- 

 tory of the successive steps of discovery, by which the struc- 

 ture of these extraordinary animals was gradually made plain, 

 is much the same as in the case of the even more peculiar 

 perissodactyl family of the fchalicotheres (p. 356). The 

 various parts, found scattered and at long intervals of time, 

 had been referred to no less than three different mammalian 



Fig. 205. — Skull of \Agnoch(Erus lalifrons, White River. (After Wortman.) 



orders ! for, until the discovery of fchalicothere skeletons gave 

 the clue, no one imagined that such discordant parts could 

 belong to the same animal. 



The fagriochcerids had a very much shorter career than the 

 allied family of the foreodonts, extending only through the 

 upper Eocene and the Oligocene (Uinta to John Day, inclusive) ; 

 and only two genera of the family are yet known, \Agriochoerus 

 of the John Day and White River, and "fProtagriochoerus of the 

 Uinta. In the former the teeth were not in a continuous, 

 closely crowded series, but there were open spaces behind the 

 upper canine and first lower premolar ; the same exceptional 

 character of the lower teeth which was found in the foreodonts 

 was repeated in the present family, the canine assuming the 



