442 



NATURAL SCIENCE. 



June, 



PAL^ARCTIC. 



Columbida : 



loi. Turtur (8) 



Pteroclida : 



102. Pterocles (6) 



103. Syrrhaptes (2) 



BOTH. 



Falconida — [continued) : 



47. Astur (2.1) 



48. Accipiter (4.2) 



49. Elanus (i.i) 



50. Falco (17.8) 



51. Pandion (i.i) 



Columbida : 



52. Columba (14.3) 



NEARCTIC 



Cohtmbida : 



loi. Ectopistes (i) 



102. Zenaidura (i) 



103. Columbigallina (i) 



104. Scardafella (i) 



Turnicida : 



118. Turnix (3) 



By merely glancing over these lists we see at once how greatly 

 the genera in either the first or third column exceeds those in the middle 

 column. This tells us that the speciality of each region in relation 

 to the other is very much greater than their similarity. In order, 

 however, to bring out these differences and resemblances more 

 clearly, and to show what they imply, the facts are summarised 

 in the following table of the families, giving the distribution of their 

 genera and species in the same order as in the preceding lists : — 



