THE SKELETON IN MAMMALIA. THE TEETH. 439 



as in the ^Eluroidea and Cynoidea. In the bears, Ursidae, 

 the molars have broad flat tuberculated crowns (fig. 85). The 



31 42 

 dental formula in Ursus is i - c pm ra , total 42. The 



upper carnassial (fig. 84, III.) differs from that of the 

 roidea and Cynoidea in having no inner lobe supported on a 

 third root. In the large group of Mustelidae there are gene- 

 rally two molars in the lower and one in the upper jaw. The 

 grinding teeth commonly have large, flattened, more or less 

 tuberculated crowns, and the upper molar may be as large or 

 much smaller than the carnassial. 



In the CREODONTA there are no specially differentiated 

 carnassial teeth. 



pm1 



3 



FIG. 86. LEFT MANDIBULAR RAMUS OF THE SEA LEOPARD (Ogmorhinus 

 leptonyx) WITH THE ROOTS OF THE TEETH EXPOSED x . (Ckmb. Mus.) 



1. condyle. pml, ^w4. first and fourth pre- 



2. coronoid process. molars. 

 i 3. third incisor. m. molar. 



c. canine. 



In the PINNIPEDIA the dentition differs considerably from 

 that of the Garni vora vera. The milk dentition is always 

 vestigial, and the teeth are frequently absorbed before birth. 

 There are four premolars and one molar, forming an uniform 

 series of cheek teeth, all of which except in the Walrus have 

 compressed and pointed, never flattened, crowns. There is 

 no special carnassial tooth, and the incisors are always fewer 

 than jj . In Otaria the dentition is 



* 9 c T P m 7 m - > tot&l 34 or 36. 



