EVOLUTION OF THE HORSE AND THE ELEPHANT 427 



From Lull's "Evolution of the Elephant " 



FIG. 200. Evolution of the group of elephants, e, Maeritherium (middle Eocene 

 of Egypt) ; d, Palaomastodon (upper Eocene of Egypt) ; c, Trilophodon (or 

 Tetrabelodon) angustidens (Miocene) ; b, Mastodon (or Mammut) americanus 

 (Pleistocene) ; a, Elephas columbi, the Columbian Mammoth (Pleistocene), related 

 to the living Indian elephant. 



