104 NATURAL SCIENCE. Aug., 



pagos Islands, following the Amazonian boundary to the Atlantic, 

 while it comprehends the islands of Trinidad and Tobago, as well 

 as those which lie on the northern coast of South America." (Cf. 

 Newton, t.c, p. 744.) 



C. — The Palaearctic Region. 



This may be divided roughly into three sub-regions, besides the 



Arctic Zone, 



which corresponds with the same zone in the New World, and becomes 



a circumpolar province. The greater part of the northern Palaearctic 



Region may be denominated the 



I. Eurasian Sub-Region, 



while the southern portion forms another sub-region, which may be 

 called the 



II. Mediterraneo- Asiatic Sub-Region ; 

 the one answering to Mr. Allen's " Cold Temperate Sub-Region," 

 and the other to his " Warm Temperate Sub-Region." 



A very good idea of the limits of the breeding areas of 

 the Western European birds has lately been given by Mr. 

 Henry Seebohm in his most useful introduction to his "Geo- 

 graphical Distribution of British Birds," and on discussing with 

 him the natural geographical divisions of the European Avi- 

 fauna, he suggests that the Scandinavian mountains must form part 

 of the Arctic Zone which should extend as far south as the Doorefjeld, 

 and this would correspond with the breeding range of several Arctic 

 species, such as the Snowy Owl, &c. The Yenesei Valley, as Mr. 

 Seebohm has before pointed out, is the natural boundary between the 

 Eastern and Western Palaearctic birds, the Urals being by no means 

 a strong natural boundary. Mr. Seebohm deprecates the division of 

 the Eurasian Sub-Region into provinces, and I admit that, with the 

 data at present in our hands, it is difficult to define the limits of 

 natural provinces, but I expect that we shall ultimately have to recog- 

 nise a Central Siberian, as well as an Eastern Siberian province. The 

 former will be the breeding home of such representative forms as 

 Motacilla leema instead of M. flava, Covone sharpii instead of C. comix, 

 Sturmis menzbieri instead of S. vulgaris, etc., while the Eastern 

 Siberian Province will probably extend from the water-shed of the 

 Lena to Kamtschatka. It will contain the breeding home of Euvino- 

 vhynchus pygmaus. Dr. Stejneger advocates the recognition of a distinct 

 Kamtschatkan province. On this and other points connected with the 

 distribution of Western Palaearctic birds, his admirable paper must be 

 consulted (Bull. U.S. Nat. Mus., no. 28). As in the case of the Palae- 

 arctic Region itself, the provinces will not be found to contain 

 different families or genera, but will be characterised by representa- 

 tive species alone. 



The following will, therefore, probably be found to be the natural 

 areas of the Palaearctic Region : — 



