242 POPULAR SCIENCE MONTHLY. 



at all in the indigenous fauna of South America. These are the Car- 

 nivores (dogs, cats, etc.), the Artiodactyls (deer, bovines, camels, and 

 pigs), the Perissodactyla (horses, rhinoceroses and tapirs), and the 

 Cheiroptera (bats). Migration and animal intercommunication be- 

 tween North America and Eurasia was very frequent. The history of 

 these nine orders of mammals in North America and Eurasia developed 

 as follows : Certain families indigenous to North America both evolved 

 and remained here, others finally migrated into Europe and South 

 America. Similarly Eurasia had its continuous evolution into forms 

 which remained at home as well as into those which finally migrated 

 into North America and even into South America. 



Africa. — The most astonishing and gratifying features of recent 

 paleontological progress has been the revelation of what was taking 

 place in Africa at the same time (Andrews and Beadnell). This dis- 

 covery came with its quota of unthought of forms, also with the repre- 

 sentative of three orders which it had been prophesied would be found 

 there, namely, the Proboscidea (elephants and mastodons), the Sirenia 

 (manatees and dugongs), and the Hyracoidea (conies). The basis 

 of this prophecy was the anomalous fact that these animals suddenly 

 appeared in Europe in the Miocene and Pliocene fully formed and 

 without any ancestral bearings; it was certain that they had evolved 

 somewhere, and Africa seemed the most probable home, rather than 

 the currently accepted unknown regions of Asia. Thus by a sudden 

 bound paleontology gains the early Tertiary pedigree of the elephants 

 and of two if not three other orders. 



Africa in the early Tertiary, whether from the absence of land con- 

 nections or from climatic barriers, was a very independent zoological 

 region. Some predatory Cretaceous mammals (Creodonta or primitive 

 Carnivores) found their way in there, also certain peculiar artiodactyls 

 (Hyopotamids). Here also were two remarkable types of mammals 

 {Arsinoitherium, Barytherium) which have no known affinities else- 

 where, as well as the extremely aberrant Cetaceans or Zeuglodonts. 



The Outlook. 

 From all these continents we have, therefore, finally gathered the 

 main history during the Tertiary period of eighteen orders of mammals. 

 We have still to solve the origin of the cetaceans or whales, still to con- 

 nect many of these orders which we call ' modern ' with their sources 

 in the basal Eocene and Upper Cretaceous, still to follow the routes of 

 travel which they took from continent to continent. Encouraged by 

 the prodigious progress of the past twenty-five years, we are confident 

 that twenty-five years more will see all the present problems of history 

 solved, and judging by past experience we may look for the addition 

 of as many new and no less important ones. 



