326 the geography of mammals 



Deductions 



1. The Order of Marsupials consists of about 172 species 

 divided into thirty-nine genera and eight families. 



2. Six of these families (with thirty-six genera and 144 

 species) belong to the Australian Region ; the remaining two 

 families (with three genera and twenty-eight species) are 

 Neotropical. 



3. Two species of Phalanger have passed the northern 

 boundaries of the Australian Region into Celebes which is 

 in the Oriental Region (see Chapter V., p. 146). 



4. In a similar way a single form of Opossum (Didelphys) 

 is found in the southern part of the Nearctic Region. 



5. With these exceptions no Marsupials are found in 

 the Palsearctic, Nearctic, Oriental, and Ethiopian Regions. 



Section VI. — Distribution of Monotremes 



The geograpical limits of the fourteenth and last order 

 of mammals may be very easily pointed out, the Mono- 

 tremes (which are correctly regarded as a sub-class, Pro- 

 totheria) being absolutely restricted to the Australian 

 Region and found even here only in certain parts of it. 

 The Monotremes in these days are a failing group, con- 

 sisting only of about five species, which belong to three 

 genera and two families — the Echidnidaz or Echidnas, 

 and the Ornithorhynchidte or Duck-bills. Echidna, the 

 first-known genus of the former family, is somewhat 

 widely distributed from New Guinea over the whole of 

 Australia and Tasmania. The Papuan, Australian, and 

 Tasmanian forms of Echidna, which are closely related, 



