6 INTRODUCTION. 



pleistocene, intersected by creeks, in the plains of Darling 

 Downs, Australia. 



" The same formation has yielded evidence of a somewhat 

 smaller extinct herbivorous genus {Nototherium), combining, with 

 essential affinities to Macrupus, some of the characters of the 

 Koala {Phascolarctos). The writer has recently conmmnicated 

 descriptions and figures of the entire skull of the Nutothcrium 

 Mitchdli to the Geological Society of London. The genus Phas- 

 culomys was at the same period represented by a Wombat (P. 

 gigas) of the magnitude of a Tapir. The pleistocene marsupial 

 Carnivora presented the usual relations of size and power to the 

 Ilerbivora whose undue increase they had to check.^' 



In another work, Prof. Owen represents an almost entire 

 skull, with part of the lower jaw, of an animal [Thi/lacolco) 

 rivalling the Lion in size, the marsupial character of which is 

 demonstrated by the position of the lacrymal foramen in front 

 of the orbit, by the palatal vacuity, by the loose tympanic bone, 

 by the development of the tympanic bulla in the alisphenoid, by 

 the very small relative size of the brain, and other characters. 

 " The carnassial tooth is 2 inches 3 lines in longitudinal 

 extent, or nearly double the size of that in the Lion. The 

 upper tubercular tooth resembles, in its smallness and position, 

 that in the placental Felines. But in the lower jaw the car- 

 nassial is succeeded by two very small tubercular teeth, as in 

 Plagiaulax; and there is a socket close to the symphysis of the 

 lower jaw of Tlujlaculco, which indicates that the canine may 

 have terminated the dental series there, and have allorded an 

 additional featiue of resemblance to the Plagiaulax^ 



As might naturally be expected, the clinnitc of a country 

 which extends over more than 30 degrees of latitude is very much 

 diversitied. Cape York and Arnheim's Land are as near 1 1° 

 south as possible, while Wilson's Promontory, in Victoria, reaches 

 39°, and the southern jjart of Tasmania 4 1|°. The parts of 

 Australia approaching the Tropic differ very consiileiably from 

 its southern portions; for, lying more to the north, the latter arc 



