CREODONTA 607 



sections into which the order has now become broken up. By some 

 zoologists these have been supposed to be Marsupials, or at least to 

 show transitional characters between the Metatherian and Eutherian 

 subclasses. By others they are looked upon as belonging altogether 

 to the latter group, and as the common ancestors of existing 

 Carnivores and Insectivores, or perhaps rather as descendants or 

 relatives of such common ancestors, retaining more of the generalised 

 characters than any of the existing species. They shade off' almost 

 insensibly into numerous other forms less distinctly carnivorous, 

 to the whole of which, including the modern Insectivora, Cope 

 (to whom we are indebted for much of our knowledge of the 

 American extinct species) gives the name of BUNOTHERIA, those more 

 specially related to the existing Carnivora forming the suborder 



FIG. 278. Anterior portion of the skull of Ilycenodon leptorhynchua. (After Filhol.) 



Creodonta. These are instances, however, in which the application 

 of the principles of classification adopted in the case of existing 

 species, of which the entire structure is known, and which have 

 become divided into isolated groups by the extinction of inter- 

 mediate forms, is almost impossible. If the generally accepted view 

 of evolution is true, and the extreme modifications pass insensibly 

 into each other by minute gradations (a view the palaeontological 

 proof of which becomes strengthened by every fresh discovery), 

 there must be many of these extinct forms which cannot be 

 assigned to definitely characterised groups. There are, however, 

 some which stand out prominently from the others as formed on 

 distinct types, having no exact representatives at present living on 

 the earth. 



The more typical Creodonts appear, however, to be so closely 

 related to the true Carnivora through the extinct Miacidce (p. 539), 



