148 



NOTOTHERWM 



discuses.^ The dental formula is I ^ C -^ Pm \ M -J- ; the last 

 premolar is a great blade-shaped tooth like that of Potorous. 



Nototherium was a creature smaller than Diprotodon, but still 

 of large size ; it is believed to have been a burrowing creature, 

 and to connect the Wombats with Diprotodon. More certainly 

 allied to the existing Wombat was Phase olo mis, a AVombat as 

 big as a Tapir. 



Of extinct American Diprotodonts the Epanorthidae, already 

 referred to in connexion with the living Ckienolestes, were the most 



Fig. 75. — Xototherium mitchelli. Side view of skull. 



(After Owen.) 



prominent forms. The genus Eixinorthus occurs in the Santa Cruz 

 formation of Patagonia, which is believed to be Miocene. The 

 incisors are three in the upper jaw ; and the single incisor of each 

 ramus of the lower jaw is a great chisel-shaped, cutting instrument. 

 Ahderites is also typicall}" Diprotodont by reason of the large 

 projecting incisors of the lower jaw. It has a large cutting 

 tooth in the lower jaw, which appears to be the last premolar, 

 and is thus comparable to the great cutting tooth of the lower 

 jaw and of the upper jaw of the extinct Phalanger, Thylacolco. 



^ Quite recently [Froc. Linn. Soc. N.S. JV. 1898, p. 1) the carnivorous eliaraeter 

 of Thylacolco has been reasserted by Mr. Broom. 



