DISTRIBUTION OF MARSUPIALS AND MONOTREMES 327 



are classed by some naturalists as species, and by others 

 as sub-species. It is preferable to place them in the 

 former category, as no intermediate forms are certainly 

 known. But in Papua, besides typical Echidna, the family 

 is also represented by its larger brother, Proechidna, with 

 a single well-known species (Proechidna bruijni) and per- 

 haps another species not yet certainly distinguished. 



The second family of Monotremes embraces only the 

 excessively anomalous aquatic and fossorial form commonly 

 known as the Duck-bill (Omithorhynchus anatinus). 

 The Duck-bill occurs in Northern Queensland, and spreads 

 southwards thence into New South Wales, Victoria, and 

 South Australia. It is likewise found in Tasmania, but so 

 far as we know has never yet been obtained in any part of 

 Western Australia. 



Table of the Order Monotremata, showing the distribu- 

 tion of the species. 



Deductions 



1. The Order of Monotremes contains five species 

 referable to three genera and two families. 



2. It is entirely restricted to the Australian Region. 



