cu. 



f. 



The Ancestors of the Horse and its Relatives compared in size 



AND FORM with THEIR TYPICAL MODERN REPRESENTATIVE 



a, Hyracotheriuvi of the Lower Eocene ; b, Plagiolophus, or Orohippus, 

 of the Middle Eocene ; c, Mesohippus, of the Oligocene ; d, Merychippus, of 

 the Miocene ; e, Pliohippus, of the Pliocene ; /, the Horse, Equus caballus. 



