554 SCLATER ON BIRDS OF THE NEOTROPICAL REGION. [Julie 17, 



is shrunk and depauperized in North Asia, Europe, and North 

 America, becomes at once intelligible, if we suppose that India and 

 South Africa had but a scanty mammalian 'population before the 

 Miocene immigration, while the conditions were highly favourable to 

 the new comers. It is to be supposed that these new regions offered 

 themselves to the Miocene Ungulates, as South America and Aus- 

 tralia offered themselves to the cattle, sheep, and horses of modern 

 colonists ; but after these great areas were thus peopled came the 

 glacial epoch, during which the excessive cold, to say nothing of 

 depression and ice-covering, must have almost depopulated all the 

 northern parts of Arctogaea, destroying all the higher mammalian 

 forms, except those which, like the Elephant and Rhinoceros, could 

 adjust their coats to the altered conditions." 



June 17, 1873. 

 The Viscount Walden, F.R.S., President, in the Chair. 



Mr. Sclater laid before the meeting the first sheets of a catalogue 

 of the birds of the Neotropical Region, prepared by himself and Mr. 

 Salvia, and shortly about to be published, under the title ' Nomen- 

 clator Avium Neotropicalium.' 



The subjoined list shows the proposed arrangement, which had 

 been based on Prof. Huxley's new classification ; and the numbers 

 appended to each order gave the number of species of the order known 

 to the authors as occurring in the Neotropical Region, which thus 

 appeared to contain not less than 3565 species : — 



Subordo I. Aves carinat^e. 



Subordo II. Aves ratit^e. 



20. Apteryges, 0. 



21. Struthiones, 3. 



During the revision of his collection, effected while this list was in 

 preparation, Mr. Sclater had found it necessary to make numerous 

 alterations in the nomenclature and arrangement of his Catalogue of 



