Geographical Distribution 373 



genera occur without the limits of the Sub-Region. There 

 live the Mohos {Drepanis), and quite a number of other 

 Passerine genera, such as Heterorhynchus, Loxops, Hima- 

 tione, Oreomyza, etc. 



E. THE NEARCTIC REGION. 



As with the Palaearctic Region, there seem to be a 

 number of Provinces which correspond in some degree with 

 those of the latter Region, but there is this difference 

 between them that, whereas in the Palaearctic Region 

 little attempt has been made to define the limits of the 

 various Provinces, in North America most careful work 

 has been done, and the natural zoological divisions have 

 been tabulated by Dr. C. Hart Merriam and Prof. J. J. 

 Allen. 



I. THE ARCTIC SUB-REGION. 



This corresponds to the Arctic Sub- Region of the Old 

 World, and the two together form a circumpolar Sub- 

 Region. It is the home of the Greenland Gyr- Falcon 

 (Hierofalco candicans), the Snowy Owl (Nyctea nyctea), 

 Ross' Gull {Rhodostethia rosea), and it is within this area 

 that the Knot (Tringa canutus) and the Sanderling (Calidris 

 arenarid) breed, as well as many Ducks and Sea-fowl. 

 The Snow-Bunting {Plectrophenax nivalis) is the most 

 characteristic Passerine bird. The limit of this Sub-Region 

 is from about the Arctic Circle on the west of North 

 America, to about 50 N. Lat. on the coast of Labrador, 

 and it includes the whole of Greenland. Two " faunae " 

 are recognized by Prof. Allen within its limits, viz. the 

 Barren Grounds and the Alaskan-Arctic. 



