250 M. Marcel de Serres on the Distinctive Characters 



transverse diameter is less, other proportions being the same 

 than in the wolf; and thus the fox, in this particular, presents 

 a kind of mean between the other two. 



The form of the maxillary bones, and the arrangement of the 

 teeth, likewise supply very good distinctive characters. Thus 

 the intermaxillary portion which supports the superior incisors, 

 usually appears larger in the different races of the dog than in 

 the wolf; and, if this distinction is not so marked in the fox, it 

 may at least be noticed, that in it the superior-incisors are more 

 widely separated from each other than they are either in the 

 wolf or in any variety of the dog. 



The canine teeth of the dog are thicker and shorter than those 

 of the wolf and fox. The latter of these animals is particularly 

 distinguished by having its canine teeth very long, very acute, 

 and probably thinner than in the dog or wolf. Their length is 

 such, that when the incisors are in contact, the superior canines 

 descend lower than the level of the inferior maxillary, which 

 corresponds to them ; and, in the same way, the inferior ca- 

 nines, in ascending, mount up considerably above the level of 

 the floor of the nasal fossae ; appearances which are not witnessed 

 either in the wolf, or in any of the varieties of the dog. This 

 distinction is the more striking, as the canines in the fox have a 

 more decided curve than the same teeth in the dog and wolf. 

 In the young fox, the milk canine teeth are furnished, at the 

 base of their posterior aspect, with small tubercles, which are 

 not to be found on the permanent teeth. 



The molares of the fox also present some peculiarities. The 

 false molares so exactly cross each other, that when they are ap- 

 proximated, the point of the superior corresponds to the junc- 

 tion of the anterior and posterior edge of two inferior teeth. 

 Thus their points nearly fill the void spaces which separate the 

 teeth from each other. In consequence of this arrangement, 

 these teeth are, as it were, inserted into each other, an appear- 

 ance which is not presented in the dog or the wolf. In this last, 

 in fact, the point of the superior molares projects before and be- 

 yond the point or most elevated tubercle of the inferior false mo- 

 lares; so that, in consequence of the oblique direction of the 

 teeth of the upper jaw, there exists a considerable void space, 



