n8 THE STORY OF THE BIRDS 



its geographical distribution. Its representatives 

 are found almost as high in the Arctic Regions as 

 land is known, in every temperate zone, and 

 throughout the tropics and equatorial regions. 

 Many of the families and genera, however, are 

 limited in distribution, and some of the more 

 specialised or aberrant forms are extremely 

 local. These it may be as well to deal with 

 first. One of the most compact and geo- 

 graphically self-contained of these sub-groups 

 is the Curassows and Guans, which are distri- 

 buted over the Neotropical Region from Mexico 

 southwards. Their dispersal is largely depen- 

 dent upon forests, in which they love to dwell, 

 and their limits are practically confined between 

 the two tropics. Returning to the Old World 

 we have that other aberrant family, the Mega- 

 podes, which forms such a distinctive avine 

 feature of the Australian Region. Mound Birds 

 are distributed over most parts of Australia, but 

 do not inhabit New Zealand. Northwards the 

 family is well represented among the various 

 islands from New Guinea to the Philippines and 

 westwards to the Nicobars, the species inhabiting 

 the latter islands being, however, so isolated from 

 the others of the family and yet so closely allied to 

 some of them, that doubts have been expressed 



