AUSTRALIAN MAMMALS. 431 



the marsupial pouch. The dental formula of Diprotodon 

 was i ^, c |, p J-=^, m ^~ = 28,* and, as in Macropus major, 

 the first of the grinding series (p) was soon shed; but the 

 other four two-ridged teeth were longer retained, and the 

 front upper incisor (i, i) was very large and scalpriform, as in 

 the wombat. The zygomatic arch sent down a process for 

 augmenting the origin of the masseter muscle, as in the 

 kangaroo. The foregoing skull, with parts of the skeleton, 

 of the Diprotodon Austrcdis, were discovered in a lacustrine 

 deposit, probably upper pliocene, intersected by creeks, in the 

 plains of Darling Downs, Australia. 



The same formation has yielded evidence of a somewhat 

 smaller extinct herbivorous genus (Noto- 

 therium), combining, with essential affi- 

 nities to Macropus, some of the characters 

 of the Koala (Phascolarcttis).^ The 

 writer has recently communicated de- 

 scriptions and figures of the entire skull Fl §'- 172 - 

 of the Rototherium Mitchdli to the Geo- ^fSSSSjf rfS 

 logical Society of London.? The genus ( nat - size )> Pleistocene, 



& J . Australia. 



Phascolomys was represented, at the plio- 

 cene period in Australia, by a wombat (P. gigas) of the 

 magnitude of a tapir, one of the grinding teeth of which is 

 figured, of the natural size, in fig. 172. 



The pliocene marsupial Camivora presented the usual 

 relations of size and power to the Herbivora, whose undue 

 increase they had to check. Fig. 173 represents an almost 

 entire skull, with part of the lower jaw of an animal rivalling 

 the lion in size, the marsupiality of which is demonstrated by 

 the position of the lacrymal foramen (I) in front of the orbit ; 

 by the palatal vacuity (p), by the loose tympanic bone, by the 



* See that of Macropus, explained in Ency. Brit., article Odontology, p. 449. 

 ■f " Eeport on the extinct Mammals of Australia," Trans, of Brit. Assoc, 

 1844. 



+ Quarterly Journal of the Geol. Soc, pt. iv., 1858. 



