286 



nally trenchant type of the premolar in existing Carpophagous and Pocphagous Marsu- 

 pials into the crushing character shown in the homologous tooth of the larger marsupial 

 Herbivores. The rest of the molar series in Nototherium differs from that in Diprotodon 

 by the smaller size and in the smoother enamel ; and, perhaps, in a little stronger indi- 

 cation of the production of the hind part, near the inner end, of the transverse lobes, 

 especially of the front one. 



In the incisor series the generic character of Nototherium is strongly marked by the 

 form, structure, and nature of the front upper incisor, as before described : and in this 

 character we see a nearer approach of Nototherium to Macropus, while the characters 

 of the front upper incisor in Diprotodon approximate that genus to Phascolomys. But 

 in the number and disposition of the upper incisors, as in the bilophodont molars of 

 limited growth, both the large extinct genera retain the poephagous character, as con- 

 tradistinguished from the rhizophagous modification shown by the Wombats among the 

 existing marsupial Herbivores. 



The lower incisor of Nototherium shows more of the scalpriform character, at least in 

 the young individual, than does the upper one ; but, in the full-grown animal, 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 Wombats. In Nototherium 

 the lower incisor differs from that in Diprotodon in being narrower, with the enamel 

 continued less far or high upon the inner side : this tooth in the young specimen increases 

 more rapidly as it sinks in the socket ; but this may be a repetition of an immature 

 character, which is shown, in a minor degree, in the jaw of the young Diprotodon described 

 and figured in the preceding section*. The widely open base of the growing incisor does 

 not, however, extend backward beyond the first molar ; and as this part contracts and 

 solidifies in the adult, the base of the tooth and its socket are moved more forward, and 

 in one species of Notothere (N. inerme) to the anterior half of the symphysis in advance 

 of the roots of the first molar. 



I have described, in former works, some detached bonesf which from their size 

 might, and probably do, belong to the genus Nototherium ; but I have since received 

 evidence of extinct species of nearly equal size, and more nearly akin to the Wombat 

 and Kangaroo families, to which some of the fossil limb-bones from Nototherian locali- 

 ties might possibly belong. I may venture to state that the olecranon of Nototherium 

 is as little produced as in the ulna of Diprotodon. 



* Pages 197, 203, Plate XXVII. fig. 5, i. 



t An astragalus, e. g., in " Eeport on the Extinct Mammals of Australia," op. cit. p. 233, plate 5. figs. 1-6. 



