Courtesy of Doiibleday, Page and Co. 

 STAGES IN THE EVOLUTION OF THE PROBOSCIDEA 

 Outlines of skull and head restored by Professor R. S. Lull, 

 a— Elephant, Pleistocene period, and still surviving in tropical regions; b — Mastodon. 

 Pliocene and Pleistocene; c - Trilophodon, Miocene: d - Pal^omaslodon, Oligocene- e 

 Mcerilhermm liocene and Oligocene. The two lower figures are on a larger scale, one 'six- 

 teenth natural size; the others are on a scale of one thirty -second 



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