778 MAMMALIA. 



(3) ARCTOIDEA Bear-like Carnivores 



The tympanic bulla shows no trace of an internal septum ; the 

 paroccipital process of the exoccipital is quite apart from the 

 bulla, and widely separated from the mastoid process of 

 the periotic. The limbs are plantigrade or sub-plantigrade, 

 and always bear five toes. There is no caecum. 



Family Ursidse Bears. The molars have broad tuberculated crowns 

 used for grinding. The three anterior premolars are usually 

 rudimentary. The auditory bulla is depressed. In relation to 

 the character of the teeth, it should be noted that the diet is at 

 least in part vegetarian ; even the polar bear eats herbs in the 



summer. Ursus, ^H? 9 absent from Ethiopian and Australian 



regions, represented in the Neotropical region by only one 



species, elsewhere widespread. 

 Family Procyonidse The Himalayan Panda (AZlurus fulgens), the 



American raccoon (Procyon). 

 Family Mustelidse The otter (Lutra), the sea-otter (Latax lutrts), 



the skunk (Mephitis}, the badger (Me/es), the ratel (Mellivora], 



the marten, sable, polecat, stoat, weasel (Muslela). 



CREODONTA (extinct) 



In Eocene and early Miocene strata, in Europe and America, there 

 are remains of what seem to be generalised Carnivora, ancestral to the 

 modern types, and apparently related to Insectivora as well. Those 

 included in the sub-order Creodonta have strong canines but no single 

 carnassials, while the molars are often like those of Marsupials. The 

 brain seems to have been small. 



Examples. Hyanodon, Proviverra^ Arctocyon. 



Order PINNIPEDIA. Seals, Eared Seals, and Walruses 



Marine Carnivores, unable to move readily on land, but coming 

 ashore for breeding purposes. They feed for the most part on fish, 

 molluscs, and crustaceans. Absent from the tropics, they are repre- 

 sented on most of the coasts in temperate and Arctic zones. Many are 

 markedly gregarious. 



The upper parts of the limbs are included within the skin and general 

 contour of the body. There are five well-developed digits connected 

 by a web of skin. In the hind-foot the first and fifth toes are generally 

 stouter and longer than the rest. There are no clavicles. The tail is 

 very short. 



The small milk-teeth are absorbed before or immediately after 



birth. The incisors are always fewer than ^ ; there are no carnassials ; 



the back teeth have pointed cusps, often sloping slightly backwards. 



The cranial cavity is rounded ; there is a characteristic interorbital 

 constriction. 



The brain is large and well convoluted. The eyes are large and 

 prominent, with a flat cornea. The external ear is small or absent. 



