VERTEBRATA: MAMMALIA. 



735 





sharp cutting-edge ; whereas in other cases the corresponding 

 teeth are blunt and " tuberculated." Even in their most tren- 

 chant condition, the carnassial tooth commonly has a more or 

 less developed tuberculated process or heel, on the inside of 

 its cutting edge. In various Carnivores a number, or all, of 

 the praemolars and molars may be " tuberculate," their crowns 

 being adapted for bruising rather than cutting. As a general 

 rule, the shorter the jaw, and the fewer the praemolars and 

 molars, the more carnivorous is the animal. The jaws are so 

 articulated as to admit of vertical but not of horizontal move- 

 ments ; the zygomatic arches are greatly developed to give 

 room for the powerful muscles of the jaws ; and the orbits are 

 not separated from the temporal fossae. The intestine is com- 

 paratively short. 



In all the Carnivora the clavicles are either altogether ivanting, 

 or are quite rudimentary. The toes are 'provided with sharp { 

 curved claws. The teats are abdominal ; and the placenta is 

 deciduate and zonular. 



The order Carnivora is divided into three very natural sec- 

 tions : 



Section I. P'mnigrada or Pinnipedia. This section comprises 

 the Seals and Walruses, in which the fore and hind limbs are 

 short, and are expanded into broad webbed swimming-paddles 

 (fig. 424, B). The hind-feet are placed very far back, nearly 



irada, Foot of Bear ; 



Fig. 424. Foot of Carnivora (after Owen). A, Plantign 



B, Pinnigrada, Hind-feet of Seal ; C, Digitigrada, Foot of Lion. 



in a line with the axis of the body, and they are more or less 

 tied down to the tail by the integuments. 



Section II. Plantigrada. This section comprises the Bears, 



