150 CARNIVORES. 



THE PRIMITIVE CARNIVORES. 



No account of the Carnivores would be complete without some reference, 

 however brief, to a number of peculiar species occurring in the Miocene and 

 Eocene formations of Europe and America, which differ so remarkably from all 

 living terrestrial representatives of the order, as to render it imperative to refer 

 them to a totally distinct group. These extinct primitive, or, as they are techni- 

 cally called, Creodont Carnivores, differ from modern land Carnivores in the 

 absence of a distinct flesh-tooth in either jaw ; all the molar teeth of each jaw 

 being constructed on the same plan, and the whole of those in the lower jaw being 

 frequently like the single flesh-tooth of other Carnivores. As a rule, the crowns 

 of the upper molar teeth are triangular in form, and of the type noticed on p. 340 

 of the first volume. And whereas in all existing Carnivores the two bones in the 

 upper row of the wrist, technically known as the scaphoid and lunar, are com- 

 pletely welded together, in nearly all the Creodonts they remain quite distinct. 

 These and other characters indicate that these primitive Carnivores are a much 

 more generalised group than the modern land Carnivores, of which they may have 

 been the direct ancestors. Moreover, the teeth of many of these extinct forms are 

 so like those of the carniyorous Marsupials (although agreeing generally in number 

 with the modern carnivorous type, as exemplified by some of the dogs), that there 

 is considerable probability that in these animals we have a direct connecting link 

 between the Marsupials and the existing land Carnivores. The best known repre- 

 sentatives of this group in Europe have been described under the names of Hyceno- 

 don and Pterodon ; and while some of the species were no larger than a fox, 

 others attained dimensions nearly or fully equal to those of a brown bear. There 

 is little doubt that from some of these primitive Carnivores and more especially 

 the North- American forms known as Miacis the majority of the existing land 

 Carnivores are descended. It is noteworthy that an American and European genus 

 known as Palceonictis shows a remarkable gradation in the structure of its teeth 

 towards the cats, although it is rather difficult to believe that the cats are directly 

 derived from this primitive form. 



