FLESH-EATING MAMMALS. 69 



they go tliey are sure to meet with herbivorous animals, on which they can 

 prey. Herbivorous animals, on the other hand, are generally more or less 

 completely dependent on one or more particular kinds of plants for susten- 

 ance, and are consequently unable to exist in regions where such plants do 

 not grow. 



In the same series with the wolves and jackals are included a number of 

 South American species, commonly spoken of as foxes, which they much 

 resemble in external aspect, although having wolf -like skulls. Among these 

 are Azara's dog (0. cnarae) and the crab-eating dog (0. cancrivorus). A much 

 larger South American form is the so-called maned wolf (0. jubatus) — a large 

 reddish-coloured animal. The so-called raccoon-dog (0. procyonides), which 

 has been generically separated as Nyctereutes, is distinguished by its long loose 

 fur, short ears, and abbreviated bushy tail, its general colour being dusky. 



Probably every Englishman thinks he knows a fox when he sees it ; and it 

 is not unlikely that he would be disposed to resent the suggestion that he 

 could not distinguish between foxes and certain other 

 members of the canine family, or that there could be any Fox-like Series, 

 hesitation in deciding whether any foxes he might be shown 

 were or were not specifically identical with the C(jmmon English kind. 

 Nevertheless, it is by no means easy to determine from external characters 

 alone whether a given canine animal is or is not a fox ; while the diiHculty of 

 deciding whether many of the lai'ger foxes of Asia and America should be re- 

 garded merely as varieties of the common fox, or as distinct species, has long 

 exercised the minds of naturalists. Indeed, the latter question has only 

 recently been decided by the leading zoologists of England in favour of the 

 former view ; and we are by no means sure that their opinions are accepted 

 by all American zoologists. 



Probably most people would say that a fox is sufficiently characterised by 

 his slight build, elongated body, short limbs, long ears, sharp muzzle, and 

 long bushy tail, of which the length always considerably exceeds half that of 

 the head and body. So far, indeed, as they go, these characteristics are ex- 

 cellent, and they will serve to distinguish a fox from a wolf or jackal. The 

 whole of them are, however, not applicable to all foxes, the Arctic fox having 

 comparatively short ears, while they will not serve to distinguish foxes from 

 the above-mentioned South American representatives of the family, such as 

 the so-called Azara's dog. The latter animals have, indeed, the general 

 build and appearance of foxes, their muzzles being sharp, their ears long, and 

 their tails of great length and thickly haired. The naturalist says emphati- 

 cally, however, that they are not true foxes, and it is, therefore, evident 

 that he has certain characteristics to rely on which are not included among 

 those just mentioned. 



A more careful examination of a fox will show that the pupil of the eye 

 forms merely a narrow vertical ellipse when seen in a strong light, whereas 

 that of wolves, jackals, and dogs is circular. Unfortunately, however, even 

 this character will not serve to distinguish foxes from the above-mentioned 

 South American species. Of more importance is the circumstance that 

 vixen foxes have but 6 teats, whereas the females of wolves, jackals, and 

 dogs generally have 10, but occasionally only 8 teats, while in the 

 Indian wild dogs the number is increased to 12 or 14. As usual, how- 

 ever, when he wants to find a feature which shall be absolutely 

 characteristic, the naturalist has recourse to the skull in order to definitely 

 separate foxes from all other members of the family. If, indeed, we examine 



