118 COLOUR AND DISTRIBUTION. [CH. II 



IV. The Novo-Zealanian sub-region comprising New 

 Zealand and some of the adjacent islands is described 

 in detail below. 



Some graphic Methods of presenting the facts 



of Distribution. 



In order to get a clear idea of the facts of Zoogeography 

 and to compare one series of facts with another it is 

 requisite to present them in a graphic fashion. The usual 

 method is to indicate the different Distributional regions 

 upon a map by the help of varied colour. The colour 

 might even be made to some extent appropriate ; the 

 Neotropical region Dendrogsea as Mr Sclater terms it 

 preeminently a region of forests and inhabited by so many 

 arboreal types, might be conveniently coloured green ; 

 those who accept the Holarctic realm of Prof. Newton 

 might suitably leave it white in order to suggest the 

 characteristic Arctic forms. Prof. Camerano has recently 

 attempted to show that there is a distinct relation between 

 colour and geographical range. He thinks that yellow is 

 the prevailing colour in Africa, grey in Asia and so forth. 

 This method of colouring the primary regions may com- 

 mend itself to some. A difficulty is offered by the 

 transitional tracts which combine the characters of the 

 two regions between which they lie. These transitional 

 areas are perhaps more marked between the Palaearctic 

 and the Ethiopian on the one hand and between the 

 Palsearctic and Oriental on the other. Prof. Mobius 1 

 colours these transitional areas with a paler hue of the 



1 Die Tiergebiete derErde &c. Archiv f. Naturg. 1891, p. 277. 



