CONNECTING AND MISSING LINKS 



have come to a natural end at one time or another, so that we 

 now have but two, or at most three, terminal lines, repre- 

 sented by the true horses, the asses, and the zebras. The 

 lineage of each of these forms is apparently traceable back 

 through millions of years, until the lines ultimately merge. 



But it is with the lineage of Man that we are chiefly con- 

 cerned. Out of some unknown line of primitive mammals 

 arose those small beasts of prey whose lack of prowess 

 necessitated their feeding on such feeble folk as they could 

 overcome — worms, slugs, insects, and small lizards. These 

 beasts are represented in the living fauna by the Insectivora, 

 such as the shrew, the mole, and the hedgehog, which repre- 

 sent ancient lines of descent and display rather conservative 

 forms. As primitive offshoots of this group came on the 

 one hand the stronger feral animals, known as the Carnivora, 

 and a group of tree folk, the Primates. Where the original 

 home of the Primates was we do not know, but we strongly 

 suspect that it was some circumpolar region of salubrious 

 climate where extensive persistently green forests afforded 

 them asylum and an abundance of easily obtainable food. 

 Fossil plants of Eocene age comparable with those living in 

 Cuba today have been found in Greenland and Spitzbergen. 

 It is safe to assume, therefore, that the climate of those 

 lands was then also comparable. From early Eocene time 

 we have a definite fossil record of Primates in England and 

 in Wyoming, some of the American forms being well-nigh 

 identical with the living lemurs or half-apes of Madagascar, 

 an identity implying that these again are persistent types, or 

 "living fossils." In North America these early Primates 

 lingered throughout the Eocene but disappeared there when 

 a change of climate destroyed the tropical forests that had 

 been their home. They migrated through Central America 

 to South America, where their somewhat altered descendants 



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