7i6 



MAMMALIA. 



Almost all have well-developed claws; there are never 

 fewer than four toes. The teeth are always rooted, except 



Fig. 318. — Lower surface of dog's skull. 



o.c, Occipital condyle; B.O., basioccipital ; T., tympanic bulla; 

 m.c, postglenoid process behind fossa for condyle of mandible ; 

 B.S., basisphenoid ; P.S., base of presphenoid ; V., vomer; 

 M.i, second molar; M.i, first molar; Pm.i-$, premolars, the 

 4th the large carnassial ; c, canine; /.1-3, incisors; Pmjc., 

 premaxilla ; mx., maxilla; Pal., palatine; J., jugal ; A.S., 

 alisphenoid ; Pt., pterygoid ; Sq., squamosal (the reference line 

 points to the glenoid cavity). 



in the case of the tusks of the walrus ; the canines are 

 strong and sharp ; some of the back teeth are generally 

 sharp, and specially adapted for cutting. 

 There are generally strong occipital and sagittal crests for 



