DISTRIBUTION IN SPACE 121 



monkeys that in other parts of the world 

 have unquestionably checked the increase and 

 development of birds in this order. As a proof 

 of the richness of this region in these birds we 

 may state that the number of known species of 

 Pigeons contained in it is nearly equal to that 

 in all other parts of the world combined. Many 

 of the genera are very local, confined to a single 

 island or group of islands. The most widely 

 ranging groups are the Typical Pigeons (Columba) 

 and the Turtle Doves (Turtur), the former of 

 these being nearly cosmopolitan with the excep- 

 tion of the Australian Region, the latter is not 

 represented in the New World, and is absent 

 from nearly the whole of the Australian Region. 

 Roughly speaking, the distribution of the five 

 families is as follows. The Fruit Pigeons (Trero- 

 nidae) are all natives of the Old World, common 

 to the Oriental and Ethiopian Regions. The 

 Typical Pigeons (Columbidae) are cosmopolitan 

 within the limits already indicated, as are also 

 the Ground Pigeons and Doves (Peristeridae). 

 The Crowned Pigeons (Gouridae) are very local, 

 confined to New Guinea and a few of the neigh- 

 bouring islands ; whilst the Tooth-billed Pigeon, 

 the sole member of its family (Didunculidae), 

 is the most local of all, and restricted to the 



