MAMMALIA 



499 



The skull is seen in side view in Fig. 343. Notice speci- 

 ally the continuation of the malar to the glenoid cavity, and 



Fig. 343. -Lateral View of Skull of a Young Kangaroo. 

 {Ad nat. ) 



I.acrymal Foramen. 



First Molar. 



Angle of Mandible. 



Paroccipital Process. 



Note the dentition with only two lower incisors, no canines and five cheek-teeth. 

 Also the Metatherian characters. 



Fig. 344. — Ventral View of 

 Skull of Kangaroo x \. 



{Ad nat.) 

 Incisor Teeth. 



the situation of the lacrymal 

 foramen outside the orbit, 

 the incomplete ossification 

 of the palate and the in- 

 flected angle of the lower 

 jaw\ 



The dentition is pecu- 

 liar. There are three upper 

 incisors, flat and chisel- 

 shaped, then a space or 

 diastema in which there are 

 no teeth. The canines are 

 absent, though occasionally 

 present in some kangaroos, 

 and there are five cheek- 

 teeth. But the true dental 

 formula of a kangaroo is 

 3.0.2.4, so that there should 

 be six cheek-teeth in all. 

 The reason for the discrepancy is that the first premolar 

 drops out at the same time that the second or last premolar 



