448 ORDERS OF MAMMALIA. 



The Carnivora are distinguished by always possessing two 

 sets of teeth, which are simply covered by enamel, and are 

 always of three kinds incisors, canines, and molars differ- 

 ing from one another in shape and size. The incisors are 



generally - - (except in some Seals) ; the canines are always 

 3 3 



and are invariably much larger and longer than the in- 

 cisors. The prsemolars and molars are mostly furnished with 

 cutting or trenchant edges ; but they graduate from a cutting 

 to a tuberculate form, as the diet is strictly carnivorous, or 

 becomes more or less miscellaneous. In the typical Carnivores 

 (such as the Lion and Tiger), the last tooth but one in the 

 upper jaw, and the last tooth in the lower jaw, are known as 

 the " carnassial " teeth, having a sharp cutting edge adapted 

 for dividing flesh, and generally a more or less developed tu- 

 berculated heel or process. A varying number, however, of the 

 molars and praemolars 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. 



In all the Carnivora the clavicles are either altogether want- 

 ing, or are quite rudimentary. The toes are provided with 

 sharp curved claws. 



The order Carnivora is divided into three very natural sec- 

 tions : 



Section I. Pinnigrada 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. 366, B.) The hind-feet are placed very far back, nearly 

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

 tied down to the tail by the integuments. 



Section //. Plantigrada. This section comprises the Bears 

 and their allies, in which the whole, or nearly the whole, of the 

 foot is applied to the ground, so that the animal walks upon 

 the soks of the feet (fig. 366, A.) 



Section III. Digitigrada. This section comprises the Lions, 

 Tigers, Cats, Dogs, &c., in which the heel of the foot is raised 

 entirely off the ground, and the animal walks upon the tips of 

 the toes (fig. 366, C.) 



As regards their general distribution in time, if the little Mi- 



