282 THE MAMMALIA. 



Arctocyon (Pakeocyon blainville) ' has long since 

 been known as an animal with a brain approaching 

 that of the Marsupial type ; whereas its dentition, 

 which resembles the earlier form of pig-shaped 

 animals, Entelodon, points to the Omnivora, while it 

 has also something of the bear as a flesh-eater. 

 Further, we must mention the Hyanodon and 

 Pterodon, so often referred to, and usually defined 

 as ' mixed forms ' ; they appear somewhat later, it 

 is true, but, nevertheless, show resemblances to the 

 Marsupials for instance, in the form of their teeth 

 they are closely allied to the Thylacinse, though not 

 as regards their change of teeth. 



With these animals which are partly also 

 found in America Cope classes a whole series of 

 American genera of doubtful position mostly from 

 the Eocene ; he gives them the name of Creodonta, 

 and regards them as the ancestors of the subsequent 

 Carnivora proper. In their case the row of molars 

 is not separated definitely by a carnassial tooth, or 

 but imperfectly so : the jaws are lengthened, and 

 the muscles for chewing are placed in such a man- 

 ner that only a smaller degree of power can be 

 developed than in the subsequent true Carnivora ; 



1 Lemoine, 'Eecherches BUT les ossements fossiles deg 

 environs de Reims,' Annales des sciences nat., 1879. 



