136 BULLETIN NO. VII. 



others which are nearly confined to a vegetable diet, interme- 

 diate conditions linking these extremes. 



There are from forty-two to thirty-six teeth and two molars 

 are always present in the upper and lower jaw, while in Ursus 

 a third molar is found in the lower jaw. The crowns of the 

 molars are tuberculate, the prominences in some cases being 

 high and sharp, but in true bears are low and the crown is also 

 marked by various wrinkles and elevations. These teeth are 

 in many respects not unlike the molars of swine. There are 

 normally four pre-molars in each jaw as in Ursus, Ailuropus, 

 Procyon, Nasua and Bassaris. In Ailurus there are but three 

 in the upper jaw, while a like reduction is also found in the 

 lower jaw of Arctictis and Cercolepies. 



There is a tendency to reduce the number of pre-molars with 

 age. In the true bears these teeth are reduced in size and 

 have conical crowns, while the smaller members of the family 

 have sharp triangular middle lobes. The incisors and canines 

 have the form common to Carnivora and are often of great size. 



The nearest relatives now living are the Civet cats which 

 some of the smaller forms greatly resemble. The plantigrade 

 walk, which is perhaps the most marked peculiarity of bears, 

 is also found among certain Viverridce, while there are a few 

 of the Ursidce which have retractile claws. 



The two sub -families are well marked and distinct groups. 

 The Subursince include the long-tailed, small-bodied forms, 

 almost confined to America. The number of teeth is never 

 more than forty (except in the aberrant ^Eluropus. ) 



The Ur since, include, besides Ursus proper, several species 

 of tropical bears. 



The Prochilus labiatus inhabits Ceylon and India and is char- 

 acterized by its long, flat head, overhanging lips and protrusi- 

 ble snout and the long, curved claws. It is arboreal and lives 

 largely upon honey. 



A still better climber is the sun bear, which inhabits the 

 Sunda Islands, etc. , and is vegetarian in habit and is particu- 

 larly partial to the cocoanut. 



SUBFAMILY SUBUKSIN^E. 



This group is composed of several genera of small animals 

 represented in North America by the raccoons or lavatory 

 bears. The genera are more strictly localized than in the 

 larger division of the Ursidce, but as a whole the group is 



