248 
PROFESSOR OWEN ON THE FOSSIL MAMMALS OF AUSTRALIA. 
was dieted on bread and milk. “ In its native grassy haunts its food consists of insects 
and their larvae, and the roots of trees and plants”*, for the mastication of which its 
broad flat grinders f are well adapted. Nevertheless the canines proper are separated 
in the upper jaw by not fewer than ten incisors, and in the lower jaw by six incisors^;. 
The cloven-footed Chceropus , equally polyprotodont, but with digital characters more 
closely resembling those of the Artiodactyle Ungulates than in any other marsupial 
genus, is not carnivorous. The condition of the molars associated with the “ three or 
more incisors followed by a canine on each side of the jaw,” clearly points to that fact. 
The accomplished naturalist and explorer of Australian haunts of animal life thus tes- 
tifies of Chceropus castanotis : — “As its dentition would indicate, its food consists of 
insects and their larvae, and of vegetable substances of some kind, probably the bark of 
trees and tuberous roots’’^. 
In fact the parallel and convergent modifications of all those structures which truly 
influence and indicate the food and habits of the animal have been noticed by all who 
have devoted the requisite attention to the Marsupial order. Gould well remarks, 
“ Hypsiprymni grub the ground for roots, and live somewhat after the manner of Pera- 
melides , with which, however, they have no relationship” || ; meaning within the ordinal 
limits — the one group being “diprotodont,” the other “polyprotodont,” with modifications 
of the two subordinal types bringing them to close similarity, if not identity, of locomo- 
tion, diet, and mode of obtaining food. 
In the case of a fossil mandible of either genus the palaeontologist, referring to the 
molar teeth, would be led to the like inference as to food and habits, although he would 
see in one a pair of large approximate incisors and no canines, in the other canines 
with small incisors interposed. 
Fig. 14. Fig. 15. 
.1 
l 
Mandible and teeth, Thylacoleo, reduced 
to one-fourth nat. size. 
Mandible and teeth, Plagiaulax, magnified 4 dia- 
meters. (After Falconek, Quarterly Journal of the 
Geological Society, vol. xiii. 1857, p. 280, fig. 14.) 
Thylacoleo (fig. 14) and Plagiaulax (fig. 15) more closely resemble each other in 
* Gould, tom. fit. ( Peragalea lagotis). 
t Cyclopaedia of Anatomy, vol. iii. (1841), Art. “ Marsupialia,” p. 274, fig. 96. 
+ lb. Art. “ Marsupialia,” ut supra. § Gould, ‘ Mammals of Australia,’ vol. i. ( Chceropus ). 
|| Id. ib. Introduction, p. xix. 
