DOGS AND BEARS. 187 



together with some less typical forms, which need not 

 be further alluded to on this occasion. 



So wide, indeed, is the gap between these two groups, 

 that naturalists have not only placed them in distinct 

 families, but have even brigaded the family of the 

 bears, together with that of the weasels, badgers, otters, 

 &c., and that of the racoons, in a common section to 

 which they have given the name of the arctoid or bear- 

 like carnivores, while they rank the dogs in another 

 section of equivalent value, to which the name of the 

 canoid, or dog-like carnivores, is applied. That this 

 division is a perfectly natural one so far as regards the 

 animals existing at the present day there is no doubt ; 

 but when our investigations are carried back to the con- 

 sideration of the varied forms of carnivorous animals 

 whose remains occur in the rocks of the Tertiary, or 

 latest geological period of the earth's history, it has 

 been found that animals then existed which so com- 

 pletely bridge over this gap that there appear to be no 

 distinctive characters by which the bears and the dogs 

 can be absolutely separated from one another. It will 

 of course be apparent to the reader that when we have 

 to determine the mutual relations of extinct fossil 

 animals we have to depend solely upon the structure of 

 their bones and teeth, and we can therefore say nothing 

 as to the appearance of these old-world forms when 

 clothed with flesh and fur. Fortunately, however, in 

 the present, as in many other instances, the bones and 

 teeth are amply sufficient to give us a very fair idea 

 of the relationship of the fossil to the living forms, 



