Land and Fresh-water Vertebrates in Victoria. 53 



(J/, ualabatus and M. billardieri) and the Thylacine ranged in 

 the high woods of both regions. The two native cats, the 

 common and the ring-tailed Opossums, and the two Dormouse 

 Opossums (Dromia'a) are the representatives in Tasmania of an 

 arboreal fauna which is much more strongly developed in South 

 Victoria and Eastern Australia. The Flying Opossums and the 

 Koala, most specialised of all for life among the trees, are 

 wanting altogether in Tasmania. With the exception of the 

 common Opossum, a most enterprising and versatile animal,* 

 the Tasmanian forest forms are absent from north-west Victoria. 

 From the zoological facts we are able to arrive at some definite 

 conclusions as to the relative age of the two barriers, the Bass 

 Straits and the Dividing Range. The marked distinctness, 

 frequently extending to the genera, of the faunas of the north- 

 west plains and the well-watered south-east hill and coast 

 country points to the long persistence and ancient origin of the 

 Dividing Range. So, going on the zoological evidence only, it 

 seems clear that the Bass Straits were formed sufficiently to 

 serve as an effective barrier before the dingo and the most highly 

 differentiated tree-forms had reached southern Victoria, and after 

 the forests had been established and the streams stocked with the 

 existing fish, long after the separation or evolution of the two 

 Victorian faunas had taken place. During the process of 

 widening and deepening of the Straits, the dingo invaded 

 Victoria, the Thylacine and Tasmanian Devil disappeared, while 

 the Koala and the beautiful Flying Opossums came in from the 

 north along the eastern strip of Australia, and took possession of 

 the Gippsland forests along with a less desirable immigration of 

 the Fruit-eating Bats, and, speaking generally, the present distri- 

 bution of Vertebrates in Victoria has been effected. 



* In Kent Island this animal has in the total absence of trees taken to the ground and 

 lives among the grass tussocks. 



