BY CHARLES W. DE VIS, B.A. 405 



and in determining that relationship, he seems to have allowed 

 even more weight to the cranial that he had previously conceded 

 to the dental characters of the animal which he had then regarded 

 as less nearly allied to Phascolomys than Diprotodon appeared 

 to be. 



It is almost needless to say, that from the Nototherian type of 

 dentition, that of the Wombats, recent and extinct, differs to a 

 degree which in placental mammals would be considered extreme. 

 In Phascolomys the teeth have, as all are'aware, persistent pulps, 

 and therefore continuous growth. Professor Owen carefully points 

 this out to us at p. 286, where, after correlating Nototherium with 

 Macropus and Diprotodon with Phascolomys by virtue of the front 

 upper incisor, he goes on to say — " But in the number and 

 disposition of the upper incisors as in the bilophodont molars of 

 limited growth, both the larger extinct genera retain the poephagous 

 character as contradistinguished from the rhizophagous modification 

 shown by the Wombats among the existing marsupial herbivores." 

 and further, speaking of the lower incisors, says that in the adult 

 Nototherium, "this tooth is far from having the proportions and 

 depth of implantation which make it resemble in Diprotodon the 

 lower pair of scalpriform teeth of the Wombat." These quotations 

 are necessary to show Professor Owen's opinion of the affinities of 

 the several genera as determined by the teeth. We are clearly 

 taught that in their molars neither genus of the huge grazers is 

 allied to the Wombats, and that in the incisors Diprotodon indeed 

 resembles " approximates " Phascolomys, but that Nototherium 

 does not even this — in brief that the old dentition of the latter 

 differs widely from that of the Wombat, more widely than does 

 that of Diprotodon. Now bearing in mind that our safest concep- 

 tions of the structure of an extinct mammal are based upon its 

 dentition, bearing also in mind that Diprotodon was according to 

 its dentition a browsing beast of mighty bulk, and that we know 

 nothing of it contradictory of the general analogy of limb structure 

 in other such beasts, namely, that their long bones are little more 

 than pedestals of support, we are prepared to admit without 

 hesitation, the justness of Professor Owen's ascription to it of the 



