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THE AMERICAN NATURALIST 



[Vol. XLV 



region or further north in the forest areas ; and under 

 the decidedly tropical climate which is evidenced by the 

 palms and ferns, crocodiles and primates themselves. 2 

 From this ancestral center the first primates, along with 

 other groups, migrated in all directions possible, climate 

 and land bridges being considered. This opened three 

 paths, one south into America, a second southeasterly 

 into England and France, and a third southwesterly into 

 Asia, thence ever southerly across China and India and 

 along the Indo-Madagascar isthmus (or chain of islands) 

 to Madagascar and Africa. 



The first primates, as indicated, separate into two 

 groups, first a group of long-headed (dolicocephalic) gen- 

 eral feeders with unspecialized teeth, which probably took 

 fruit, leaves, insects and small animals: and second a 

 group of short headed (brachy cephalic) fruit-eaters 

 with crowded and rather high pointed teeth. These are 



2 For a discussion of the climate see Wortman, Amer. Jour. Set, 1903, 

 Vol. 165, p. 417; and Wieland, same journal, Vol. 166, p. 401, 1903. 



