STRUCTURE OF THE VERTEBRATES 



85 



Walrus (Carnivora) 



Seal (Carnivora) 



Fig. 33. Carnivora. Aquatic or partially aquatic carnivores (Pinnipedia). 



A comparison of the Sea Lion and Seal shows the latter's increased 



specialization for water life. 



Order Carnivora. The carnivores, or flesh eaters, are distin- 

 guished by the enlargement of the canine or ''eye" teeth. The 

 posterior teeth (premolars and molars) are usually modified for 

 cutting, and the animal is able to tear and cut his food. The 

 order is divided into two large groups. (A) The land carnivores 

 include the dog family, the cats (lions, tigers, pumas, and the 

 smaller cats), the hyenas, the bears, and a few others which 

 will be unknown to most students. (B) The carnivores modified 

 for swimming form the second group: the sea-elephant, sea- 

 lion, walrus, and the Atlantic seals. The last are the most highly 

 modified for aquatic life. 



Order Rodextia. The rodents are gnawing animals and have 

 the two median incisor teeth of both jaws highly developed. The 

 posterior teeth are modified for grinding. The animals were orig- 

 inally herbivorous, although the rats and others are omniv- 

 orous. In this order are the mice, rats, guinea-pigs, and the 

 large South American capybara which is the size of a hog. By 

 some anatomists the rabbits are included in another order, due 



