xxvii. 6 THE DOGS 685 



triangular molars, unossified bulla, and separate carpal bones. There 

 was, however, a sign of the beginning of the fissipede carnassials, the 

 fourth upper premolar and first molar being elongated, the cusps 

 partly united to form a ridge. At the end of the Eocene and beginning 

 of the Oligocene early representatives of the various fissipede families 

 appeared and were presumably derived from these miacids. The dogs 

 (Canidae) (Fig. 449) appeared very early and have since changed 

 relatively little, the modern Canis being practically a survivor show- 

 ing us the Eocene stage of carnivore evolution. Numerous fossil dogs 



Fig. 449. Wolf, Canis. (From a photograph.) 



are known and the type has been a very successful one. The diet is 

 varied and partly herbivorous. The European red fox, for instance, 

 feeds on mice, hares, rabbits, and chickens, but also on snails, insects, 

 and berries. The type is not suited for climbing but for running in 

 open country, for which purpose long legs and a digitigrade habit 

 have been developed, the pollex and hallux being reduced (Fig. 354). 

 The teeth have remained unspecialized, with at least two post-carnas- 

 sial grinding molars and still distinct signs of the triangular form in 

 the carnassial (Fig. 450). Dogs, wolves, and foxes are found through- 

 out the world, including South America, but not in Madagascar or 

 New Zealand. So many types are known that the exact ancestry of the 

 various wolves and foxes has not been fully disentangled. 



The bears (Ursidae) (Fig. 451) were a Miocene offshoot from this 

 dog stock and here the tendency to non-carnivorous diet became 

 accentuated; there are no carnassials and the molars acquire bunodont 

 grinding surfaces. The gait is plantigrade. Various types are found 

 through the Holarctic region and South America. The raccoons 

 (Procyonidae) (Fig. 452) are a rather similar though smaller type 

 of animal, with dentition suited to an omnivorous diet, the upper 



