URSID^. 501 



premolar in both jaws, but by the smaller size and more simple 

 structure of the true molar teeth, with the exception of the first 

 below (fig. 15, m 1), which still indicates the sectorial character by 

 the development of a sub-compressed pointed lobe on the outer side 

 of the crown. In the small size of the last true molars the Benturong 

 manifests its affinity with the Viverrida. In the Kinkajou (PL 129, 

 fig. 16, 17), the true molars more nearly approach in form and 

 proportions those of the Coati and Raccoon : the two fangs of 

 the first and second premolars in both jaws are connate. 



187. UrsidcB. — The essential characteristic of the dentition of 

 the true Bears is the development, in the lower jaw, of the true 

 molar teeth to their typical number in the placental Mammalia, and 

 their general manifestation, in both jaws, of a tuberculate grinding 

 surface. The premolar teeth are so reduced both in size and 

 number, that for the better understanding of the nature and ana- 

 logies of the molar series, I shall commence by the description of 

 the deciduous series of teeth. 



The immature or transitory dentition of the Bear, consists of : 



t. ^^% c. J^; m. ^: = 22. (PI. 130, fig. 1 & 2.) 



The molars {d. 1, 2, 3) increase in size in a geometric ratio from 

 the first to the last, which has a middle principal subcompressed 

 cone and an anterior and posterior basal talon. The change of the 

 teeth takes place at a very early period : before any of the deciduous 

 teeth fall, the first small permanent premolar {p. 1) cuts the gum, 

 as in the Dog, without any apparent predecessor. The second pre- 

 molar {p 2) pushes out the first of the deciduous series and is itself 

 soon shed, it has a single fang : the third premolar {p 3) is also 

 small, simple, and single-fanged, like its deciduous predecessor ; it 

 is commonly retained longer than the second premolar. The fourth 

 premolar (p 4) is developed for use, and is truly permanent ; it dis- 

 places the last tricuspid deciduous molar, and though with a larger 

 crown, yet has a more simple one viewed exteriorly ; the anterior 

 talon, for example, is wanting or very feebly indicated ; the large 

 middle and the smaller posterior subcompressed pointed cones repeat 

 the proportions of those in the deciduous tooth and represent the 



