12 THE GEOGRAPHY OF MAMMALS 



although he makes many complimentary allusions to Mr. 

 Allen and his views, he employs in nearly all its entirety 

 the system adopted in this work, with the exception 

 that he recognises an Arctic Sub-region to include the 

 more northerly parts of both the Old and New worlds. 



Finally, Professor Newton, who has given us his views 

 on this subject as regards birds (7), adopts the method 

 of divisions followed here with the two following 

 exceptions. In conformity with the suggestion already 

 made to Professor Heilprin, he unites the Palsearctic and 

 Nearctic Regions under the title " Holarctic," and he also 

 separates New Zealand from Australia as an independent 

 region. 



The chief questions in dispute, therefore, seem to be as 

 follows : — 



(1) Whether the Palrearctic and Nearctic Regions are 

 to be recognised as separate ? 



(2) Whether Madagascar and New Zealand are to be 

 separated as independent regions from the Ethiopian and 

 Australian Regions respectively ? 



(3) Whether the Ethiopian and Oriental Regions should 

 be joined to form one region ? 



(4) Whether there are any good grounds for dividing 

 the Neotropical into two separate regions. 



The only way in which questions of this sort could be 

 settled would be by constructing accurate lists of the 

 families and genera of the various classes of the terres- 

 trial faunas of the regions in dispute, and then carefully 

 comparing them, in order to determine the percentage 

 of peculiar species and of absentees. The difficulty of 

 doing this satisfactorily is twofold. 



(1) The absence of any definite boundaries to most of 



