194 



NEW SPECIES OF FOSSIL BEAR 



rear molars are perfect on one side and but little damaged on the other. 

 Both canines are present, and that of the right side is entire. The alveoli of 

 the false molars and incisors are distinct, although the teeth are wanting. 

 The only considerable deficiencies are in the posterior and lower parts of 

 the occiput, both zygomatic arches, and in the lower end of the nasals, where 

 a fissure extends across the face, on both sides towards the orbits. 



The chief peculiarities of the fossil are to be found in the teeth, 

 which are constructed more after the type of the higher Carnivora than any 

 other described species of the genus. Before entering upon these it will be 

 convenient, for comparison, shortly to refer to the dentary system of the 

 Bears generally. 



The number of the teeth varies more in the different species of the 

 Bears, than in any other genus of the Carnivora. The incisors, canines, 

 and the three posterior molars are constant in both jaws, in all the species. 

 The false molars are subject to great variation. They are usually entirely 

 wanting* in the upper jaw of the Ursus spelceus, or large fossil Bear of Eu- 

 rope, while in other species they amount to three on either side. The same 

 variation holds in the lower jaw. In the Ursus lahiatus-\ there are four false 

 molars on each side, while in the Ursus spelceus there is generally but 

 one present : so that while the number of teeth in the former extends in 

 both jaws to 42, it is commonly reduced in the latter to 30. This irregu- 

 larity in the number of the false molars, exists to a certain extent in differ- 

 ent individuals of the same species. In one skull of the Ursus Tihetianus 

 in our collection, which belonged to an old animal, there are three false 

 molars in the upper jaw on each side; while in the skull of a younger indi- 

 vidual with unworn teeth, there are but two. In another skull, there are 

 no false molars on the left side, while there is one on the right side : there 

 being at the same time three false molars on either side of the lower jaw. 



The characters depending on the form of the teeth are very constant 

 in the genus. The carnassier or ante-penultimate molar, in the upper 



* CuviER, Ossemens Fossiles, torn. 4. p 351. 



t This is constant in several skulls in our collection. 



