DISTRIBUTION IN SPACE 115 



of Magellan and the Falkland Islands. Many 

 of these Ducks are arctic or sub-arctic in their 

 distribution during summer. That containing 

 the Musk Duck (Erismaturinae) is distributed 

 over the Australian, Palaearctic, Ethiopian, Ne- 

 arctic, and Neotropical Regions ; that containing 

 among other forms the Swift Ducks of the Andes 

 (Merganettine) is confined to New Zealand, 

 Waigiu, and the Andes of the Neotropical 

 Region ; whilst that containing the Mergansers 

 and Smews (Merginae) is partly Nearctic and 

 Palaearctic, and also distributed over a portion 

 of the Neotropical and Oriental Regions together 

 with the Auckland Islands. Few other homo- 

 geneous groups are more erratically dispersed, 

 although the significance of such a distribution 

 is as yet little realised by ornithologists. 



The Gruiformes are another wide-ranging 

 order, although many of the species included 

 in it are considerably localised. The Typical 

 Cranes are represented in all the great zoo- 

 logical regions, with the exception of the Neo- 

 tropical Region, or at least only just entering 

 the extreme north of that area as winter migrants. 

 A considerable number of Cranes are found in 

 the Palaearctic Region, whilst others are found 

 in the Oriental and Ethiopian Regions ; the 



