540 Mr. P. L. Sclater on the Geoyraphical 



Coerebidfe. Bucconidae. 



Oxyrliamphidse. Rhampliastidse. 



Pipridas. Palainedeidee. 



Cutingida3, Cracidae. 



Phytotomida;. Opisthocomidae. 



Dendrocolaptidae. Eurypygidae. 



Formicariidaj. Cariamidse, 



Pteroptochidae. Psophiidfe. 



Steatoniithidte. Thinocoridae. 



MomotidiB. Tinamidae. 



Todidas. llheidae. 

 Galbulidae. 



Besides these, there are at least four other groups, of 

 full family value, which, though they extend more or less 

 abundantly into the Nearctic llegion, are specially charac- 

 teristic of the Neotropical, in which they probably originated ; 

 these are, the Tanagrida, Icteridee, Trochilidce, and Cathar- 

 tidce. But beyond all other forms of bird-life the Trochi- 

 lida are pre-eminently suggestive of the Neotropical Ornis. 

 Of more than 400 known species, about 20 only have yet 

 been registered as occurring within Nearctic limits, and 

 most of these only in the extreme southern portion of 

 that region. In many other families also, and, in the 

 case of the Passeres, in }iearly all the families, the Neotro- 

 pical genera are restricted to the region, so that there can, 

 in short, be no doubt that the Neotropical Avifauna is the 

 most peculiar and the most highly developed of any part of 

 the world^s surface. 



In the ' Nomenclator Avium Neotropicalium ' (93) com- 

 piled by Mr. Salvin and myself in 1873 we attributed 3565 

 species to the Neotropical Ornis. If to these we add the 

 discoveries of the past twenty years it is probable that at 

 least 4000 species of Neotropical birds have already been 

 described, and there is no doubt that matiy remain in the 

 unexplored recesses of South America to be added to the 

 list. It is probable, in fact, that more than one third of the 

 whole number of species ot existing birds are to be met with 

 within the limits of the Neotropical Region. 



(c) Sabrcyions. — In his great work on Geographical Distri- 



