134 PRIMITIVE ANIMALS 



nutrition, have given up the habit of carrying the 

 young in a pouch, as being too cumbrous, and have 

 accelerated the weaning of the young, which are 

 early provided with a milk dentition. 



The Marsupials have never attained to a very high 

 grade of development, and their achievements have 

 been practically confined to the Australian Continent 

 and its adjuncts, Tasmania and New Guinea ; the 

 Eutherian Mammals, on the other hand, with all the 

 rest of the world as their field of activity, have 

 branched out luxuriously into all the higher types 

 of animals which we know ; the fleetness of the horse, 

 the ferocity and strength of the lion and tiger, the 

 strength of the elephant and the sagacity of man are 

 the most finished and highest products of animal 

 evolution. 



All this latter development has taken place 

 within the period of Tertiary time, and we can trace 

 in the geological record the origin of all the great 

 groups of the higher Mammalia from their common 

 origin, the Condylarthra, in Eocene times. The 

 unravelling of this history has been the triumph of 

 palaeontological science and the vindication of the 

 theory of evolution, but we are not concerned with 

 it here, as the fossil forms which serve to link together 

 the divergent groups have left few direct survivals, so 

 that among the existing Mammalia we do not meet 

 with any very striking examples of primitive animals. 



