222 THE DINGO. [CH. V 



The place of origin of the Marsupials. 



The Australian region offers difficulties which have 

 perhaps been passed over too lightly.- As is well known 

 the continent of Australia and some of the adjacent 

 islands to the northward are mainly characterised by 

 Marsupials. With the exception of the American 

 Opossums all the Marsupials are crowded into this com- 

 paratively limited tract of continent and island. In 

 addition to Marsupials there are of course the ubiquitous 

 bats, the Dingo dog and a few rodents, notably the genus 

 Hydromys, with more than one species. The Dingo has 

 been regarded as the feral descendant of a domesticated 

 dog introduced by man. M'Coy has however demon- 

 strated the existence of fossil remains of this Carnivore in 

 the Pliocene deposits of Australia, the remains of a period 

 when there were no human inhabitants of the continent. 

 On the other hand the proof has been strengthened by 

 investigations which approach the matter from another 

 side. Nehring denies that the osteological characters of 

 this dog are those of a feral animal, and affirms that it 

 presents all the features of a truly wild race. The 

 indigenous nature of the rodent inhabitants of Australia 

 have not been called in question. The line which 

 separates the Australian from the contiguous Oriental 

 region passes between the islands of Bali and Lombok and 

 between Borneo and Celebes, the last-mentioned island 

 being in each case within the Australian division. Lyell 

 shows in a sketch map of that part of the world that this 

 line (which has been called " Wallace's line ") nearly 



