WOMBAT, 393 



Macr. Atlas has the same remarkable size as the lower one displayed 

 in fig. 3, PL 101 ; the anterior end of the crown is irregularly- 

 notched, the inner surface uniform, and its margin entire ; the outer 

 surface is obliquely indented, forming a notched lobe posteriorly. 

 The outer surface of the lower premolar is more equally divided by 

 an oblique vertical fissure into two lobes. The relative size of this 

 tooth to the true molars is not only greater than in the Macropus 

 Titan, but also than in the existing true Kangaroos, {Macropus), 

 and clearly indicates a subgeneric type connecting these with the 

 Potoroos, (Hypsiprymnus) . The large procumbent flattened inferior 

 incisor displays the characteristic form of that tooth in the existing 

 Kangaroos, and has the same strengthening ridge along its inner 

 size, fig. 5. 



154. Rhizophaga. — In this tribe, the stomach is simple in out- 

 ward form, but complicated within by a large cardiac gland ; and the 

 coecum, which is short and wide, is furnished with a vermiform 

 appendage. 



Genus Phascolomys, (PI. 100, fig. 9.) — In its heavy shapeless 

 figure, large trunk, and short equably developed legs, the Wombat 

 offers as great a contrast to the Kangaroos as does the Koala, which 

 it most nearly resembles in its general outward form and w^ant of 

 tail. But in the more important characters affbrded by the teeth 

 and intestinal canal, the Wombat differs more from the Koala than 

 the latter does from either the Phalangers or Kangaroos. 



The dental system presents the extreme degree of that degrada- 

 tion of the teeth, intermediate between the front incisors and true 

 molars, which we have been tracing from the Opossum to the 

 Kangaroos : not only have the functionless premolars and canines 

 now totally disappeared, but also the posterior incisors of the upper 

 jaw, which we have seen in the Potoroos to exhibit a feeble degree of 

 development as compared with the anterior pair ; these in fact are 

 alone retained in the dentition of the Wombat, which is thus reduced 

 to that of the true Rodentia. 



Incisors - : canines - : premolars — ; molars — : = 24. 



2 ' ' -"^ 1—1 ' 4—4 



The incisors, moreover, are true denies scalprarii with persistent 



