^600. 



142 SCLATER ON THE GENERAL DISTRIBUTION OE AVES. 



well acquainted with the ornithology of that continent ; but there 

 still remains New Guinea and the multitudinous adjacent islands, 

 which doubtless contain numbers of species as yet unknown to 

 science. Mr. Gould, in his ' Birds of Australia,' enumerates — 



1 . Accipitres 36-^ 



2. Passeres 311 



3. Scansores 36 



4. Columbae 23 



5. Gallinse 16 



6. Struthiones .... 1 



7. Gralte 78 



8. Anseres 99 J 



in all 600 species. 



The most characteristic forms of this region are perhaps the 

 Paradiseidce and Epimachidce (both peculiar to it) ; the Melipha- 

 gidce, one or two genera only of which are found externally, and 

 of which between 60 and 70 species occur in Australia alone ; the 

 genera Calyptorhynchus, Microglossa, Trichoglossus, Platycercus, 

 Nestor, Strigops, and many other forms amongst the Psittacidce, 

 besides a vast number of others. 



Taking 3,000,000 of square miles as the amount of dry land in 

 this region, and allowing 1000 species as peculiar to it, we have 

 one species to every 3000 square miles, showing us that this is 

 little inferior to the middle Palseotropical Region in intensity of 

 species. 



V. Nearctic or North- American Region (Regio Nearctica). 



Extent. — Greenland and North America down to centre of 

 Mexico — area of perhaps 6,500,000 square miles. 



Characteristic forms. — Trochilus, Sialia, Toxostoma, Icteria, 

 Vireo, Mniotiltince, Chamcea, Certhia, Sitta, Neocorys, Calamospiza, 

 Zonotrichia, Picicorvus, Gymnocitta, Meleagris. 



As is the case in the Old World, most of the genera belonging 

 to the northern part of the New "World are better represented in 

 its tropical than in its temperate portions. Northern America, 

 however, produces Sylvicolce and Zonotrichia in much greater 

 abundance than southern America, and these genera (which are 

 analogous to the Sylviince and Emberizce of the Old World) are 

 perhaps its most ordinary characteristic forms. I have already 



