PHOCIDiE. 505 



The above remarkable modification of the crowns of the molar teeth 

 of the lower jaw indicates this great extinct Bear to have been more 

 * carnassial' and ferocious than the Ursus spelceus or any of its 

 existing congeners. It differs essentially from all the small Sub- 

 ursine Plantigrades in the full complement of true molar teeth in the 

 lower jaw ; and is still more removed from the genus Hy^sna, in 

 which only the first true molar is present below and under its 

 true sectorial form : the term Hycsnarctos sivalensis has, however, 

 been provisionally assigned by its Discoverers to the extinct species, 

 which, from the modification of the molars, ought to be regarded as 

 subgenerically distinct from the true Ursi. 



188. PhocidcB. — We have seen a tendency to deviate from the 

 ferine number of the incisors in the most aquatic and piscivorous 

 of the Musteline quadrupeds, viz : the Sea-otter {Enhydra) , in which 

 species the two middle incisors of the lower jaw are not developed in 

 the permanent dentition. In the family of true Seals, the incisive 

 formula is further reduced, in some species even to zero in the 

 lower jaw, and it never exceeds lEf. All the Phocidce possess power- 

 ful canines ; only in the aberrant Walrus are they absent in the lower 

 jaw, but this is compensated by the singular excess of development 

 which they manifest in the upper jaw. In the pinnigrade, as in the 

 plantigrade, family of Carnivores we find the teeth which correspond 

 to true molars more numerous than in the digitigrade species, and 

 even occasionally rising to the typical number, three on each side ; 

 but this, in the Seals, is manifested in the upper and not, as in the 

 Bears, in the lower jaw. The entire molar series usually includes 

 five, rarely six teeth on each side of the upper jaw, and five on 

 each side of the lower jaw, with crowns, which vary little in size 

 or form in the same individual : they are supported in some genera 

 as the Eared Seals {Otarice), and Elephant Seals {Cystophora PI. 132, 

 fig. 7), by a single fang; in other genera (ib. fig. 1-4) by two fangs, which 

 are usually connate in the first or second teeth : the fang or fangs of 

 both incisors, canines and molars are always remarkable for their 

 thickness, which commonly surpasses the longest diameter of the 

 crown. The crowns are most commonly compressed, conical, more 

 or less pointed, with the ' cingulum' and the anterior and posterior 



