On Land-Birds in the Philippines. 411 



39. TuKTUR HUMiLis (Teuim.) ; Salvad. Cat. B. Brit. Mus. 

 xxi. p. 434 (1893). 



"Only a few seen." — J. W. 



40, Geopelia striata (Linn.) ; Salvad. Cat. B. Brit. ]\Ius. 

 xxi. p. 458 (1893). 



'^Common."— J. W. 



XXXVI. — On the Distribution of Genera and Species of 

 Nun-migratory Land- Birds in the Philippines. By J. B. 

 SteerBj Professor of Zoology and Comparative Anatomy 

 in the University of Michigan ^. 



In the years 1887-88 a party of naturalists from the Uni- 

 versity of Michigan visited the Philippines for the purpose of 

 scientific exploration. During this visit several important 

 facts relating to the distribution of birds in these islands 

 were noticed. As one island after another was explored 

 it was found^ as was to be expected^ that most of the genera 

 of the birds were continually recurring, thus giving a general 

 similarity to the avifauna of all the islands. 



Each genus was ordinarily represented by only a single 

 species in one place; so that the number of species and the 

 number of genera in any one locality were nearly equal. 

 This resulted from the fact that in a large number of genera 

 the islands possessed but a single widely distributed species of 

 each, while in a large number of other genera, though each 

 genus was represented in the islands by several species, each 

 of these species occupied a limited area of its own, consisting 

 of one or more adjacent islands. In this limited area it 

 existed by itself, sharply separated from the other species of 

 the same genus. 



This reappearance of genera in new specific forms in each 

 distinct area was so frequent with a large number of them 

 that the members of the party learned to expect and to look 

 for local species whenever a new island was reached. 



On making a study of the distribution of the genera and 



* A paper read before the American Association for the Advance- 

 ment of Science, at Indianapolis, Aug'ust 1890. 



2f2 



