180 MAMMALIAN DENTITION 



those the diet of which is markedly omnivorous that the con- 

 dyle rises. In the purely flesh-eating Mammals the glenoid fossa 

 is a deep transverse groove permitting of no antero-posterior or 

 lateral movement but this feature may also be distinct in others 

 of the Carnivora which indulge in a more varied diet. 



The Mustelidae, called for the sake of simplicity the 

 Weasels in the earlier part of the chapter, include many and 

 varied genera which are very difficult to arrange. There are 



Fig. 63. — Dentition of Skunk (Mephitis mephitis, 9.7427-3). Note the peculiar 

 form of the single upper molar. The second right lower molar is missing in this 

 specimen. 



otter-like, badger-like and Aveasel-like forms. In this account 

 we can take only one and we choose therefore the common Skunk, 

 Mephitis mephitis (Fig. 63) a member of the second group. Al- 

 though because of the small size and fragility of the skulls of this 

 family the records of its history are by no means complete we 

 know from Oligocene ancestors that considerable changes 

 have occurred in the skull during the evolution of the Muste- 

 lidae and that the skull is now much shorter than it was. In 

 general the skulls of the Mustelinae are most like those of the 



