birds' flight, and birds' wings. 67 



the ancestors of these birds were strictly dwellers 

 in trees, and that the existing representatives of 

 these have since become dwellers on terra-firma. 

 Thus then we get from those two small points a 

 whole flood of light illuminating the past history 

 and the evolution of the whole group. 



We shall find even more convincing evidence 

 of this later on in these pages. 



There is one other point in connection with 

 birds' wings which should certainly receive men- 

 tion here. It has puzzled and baffled all attempts 

 at explaining it for the past twenty years. 



Exactly so many years ago, one Gerbe, a 

 Frenchman, discovered that in certain birds, such 

 as pigeons, gulls and parrots, for instance, one of 

 the quill-feathers of the forearm appeared to be 

 missing — No. 5. Ten years later, this same fact 

 was re-discovered and this time by an English- 

 man named Wray. Like Geibe, he held that 

 the particular quill in question was actually 

 missing, and sought amongst all orders of birds 

 hoping to find some sort of a vestige of it, but 

 in vain. The reason for assuming a lost quill 

 lay in the fact that in these wings every pair 

 of greater coverts of the wing embraced a quill 

 between them save the fifih pair, between which 

 was no quill. 



The word diastataxic has been coined to 

 signify the absence, and eutaxic the presence, of 

 this quill. 



It has since been shown that there really is 

 no quill missing, but that it has changed its re- 

 lations with the neighbouring feathers. Exactly 

 how this is done would be too long and too 



