V. S. GEOLOGICAL SURVEY 



MONOGRAPH 55 PLATE XLVIII 



Bunodont 



Bunoselenodont and 

 Brac/iyselcnodont 



SeLefwdont 



EXTINCTION OR SURVIVAL OF 23 FAMILIES OF EVEN-TOED ARTIODACTYL UNGULATES 



Note the extinilion of 13 families having bunodont and bunoselenodont grinding teeth, the survival of 3 bunodont famili 

 and the expansion of 7 selenodont famihes 



