Page:Mammals of Australia (Gould), introduction.djvu/23

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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 Macropus, some of the characters of the Koala (Phascolarctos). The writer has recently communicated descriptions and figures of the entire skull of the Nototherium Mitchelli to the Geological Society of London. The genus Phascolomys 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 Herbivora 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 (Thylacoleo) 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 carnassial 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 Thylacoleo, which indicates that the canine may have terminated the dental series there, and have afforded an additional feature of resemblance to the Plagiaulax."

As might naturally be expected, the climate of a country which extends over more than 30 degrees of latitude is very much diversified. Cape York and Arnheim's Land are as near 11° south as possible, while Wilson's Promontory, in Victoria, reaches 39°, and the southern part of Tasmania 44½°. The parts of Australia approaching the Tropic differ very considerably from its southern portions; for, lying more to the north, the latter