CHAPTER XII 



HISTORY OP THE fTOXODONTIA (OR fNOTOUNGULATA) 



It is a regrettable circumstance that, while the successive 

 Tertiary faunas are very fully represented in South America, 

 approximately complete skeletons have, as yet, been obtained 

 from only a few of the various stages; from the others the 

 known material is very fragmentary and largely made up of 

 teeth and jaws. No doubt, the history of fossil-collecting in 

 North America will, in due course of time, be repeated in the 

 southern continent and more and more complete and satis- 

 factory specimens be obtained. At present, however, it is not 

 possible to trace the modifications of structure in any given 

 series with such detail as in those which were developed within 

 the limits of Arctogsea. No such story as that of the horses, 

 the rhinoceroses or the camels, can yet be told of the South 

 American groups, whatever futm-e exploration may teach us. 

 Nevertheless, much has already been learned concerning the 

 strange creatures that once inhabited the Neotropical region 

 and long ago vanished completely, leaving no trace in the 

 modern world. 



As was mentioned in Chapter VI, on the present geographi- 

 cal distribution of mammals. South America is to-day the 

 richest and, after Australia, the most peculiar zoologically of 

 all the regions. All of the modern hoofed animals found in 

 that continent at present, the tapirs, peccaries, llamas and 

 deer, are immigrants derived at a comparatively late date 

 from the north, but throughout the Tertiary and the Pleisto- 

 cene there were several indigenous types of ungulates, and of 

 these the largest and most varied assemblage was that included 



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