THE TEETH OF MAMMALS 



127 



the canines are feeble in most species, 

 garoos (Fig. 41) have the formula, — 



The Kan- 



3-3 



l-i 



0-0 

 0-0 



p.m. 



1-1 

 1-1 



m. 



4-4 

 4-4 



28. 



The upper central incisors are large cutting teeth ; 

 the lower centrals are large and chisel-shaped, 

 and project forward horizontally with an interval 

 between them (Fig. 41-A). The two halves of the 



Fig. 41-A. — Roentgenogram of teeth of Kangaroo (Macropus gigan- 

 teus). (By Dr. E. H. Skinner.) 



lower jaw are separate and movable, for shearing 

 grass with the horizontal lower incisors. The ca- 

 nines are absent, and the premolars are shaped 

 for cutting and well developed. The molars have 

 tubercular ridged crowns. The Bandicoots have 

 canines and more incisors than the Kangaroos, 

 with the molar series more cuspidate. The 

 American Opossum has the formula, — 



