THE P^ORERUNNERS OF THE HORSE 257 



from the adjacent column of the main body of the 

 crown, which are evidently remnants of the neck 

 of enamel connectino- the latter with the anterior 



o 



Front View of the Bones of the Right Fore (a) and Ilind (d) Feet of the 

 Extinct American Hipparion, \ natural size 



pillar in the more typical members of the family. 

 The grinding surface of the anterior pillar forms 

 a regular ellipse. Another feature of the hipparion 



R 



