THE BEGINNINGS OF FLIGHT 



By courtesy of the New York Zoological Society 

 White-winged dove four days old. with wing and 

 leg extended, the latter to show the feathers of the 

 "pelvic wing" 



been fleveloped at all, and we are as 

 much in the dark as ever regarding the 

 manner of this. Archa'opirriix is very 



reptile-like; but for its feathers it might 

 be a reptile, and so far there is not the 

 slightest hint of an intermediate stage 

 between scale and feather. 



But to come back to the question of 

 flight: there are two principal theories 

 as to its origin, one that it was brought 

 about by jumping up, the other that it 

 was brought about by jumping down. 

 According to one view, the aV)out-to-be 

 l)irds ran along the ground, or jumped 

 into the air waving their fore limbs vig- 

 orously, until the time came when 

 the wings were sufficiently developed to 

 raise their owner into the air. Those 

 who hold the other view consider that 

 flight began by animals leaping from 

 trees and instinctively spreading their 

 limbs to catch at anything convenient 

 to break their fall. 



Advocates of the first theory cannot 

 bring forward a single creature that 

 today habitually runs along the ground 

 before taking flight; the best they can do 

 is to adduce the flying fish which is not 



By courtesy of the New York Zoological Society 

 "Pelvic wing" of the squab of the white-winged dove, consisting of twelve flight feathers and six coverts. 

 These feathers develop on the young bird while the body is yet bare except for the flight feathers of wing and tail 



