ch. xiv PROOFS OF ORGANISING MIND 287 



The earliest fossil bird, the Archaeopteryx, had three 

 apparently free and movable digits on the fore limbs, each 

 ending in a distinct claw ; while the two bones forming the 

 forearm appear to have been also free and movable, so that 

 the wing must have been much less compact and less 

 effective for flight than in modern birds. This bird was 

 about as large as a rook, but with a tail of twenty vertebrae, 

 each about half an inch long and bearing a pair of 

 feathers, each four inches in length and half an inch broad, 

 while the wing feathers were nearly twice as long. The 

 almost complete disappearance of the unwieldy tail, with 

 the fusing together of the wing-bones, must have gone on 

 continuously from that epoch. In the Cretaceous period the 

 long tail has disappeared, and the wing-bones are much 

 more like those of living birds ; but the jaws are still 

 toothed. In the early Tertiary deposits bird-remains are 

 more numerous, and some of the chief orders of modern birds 

 seem to have existed, while a little later modern families and 

 genera appear. 



The important point for our consideration here is that, 

 in the very earliest of the birds yet discovered which still 

 retained several reptilian characteristics, true feathers, both 

 of wings and tail, are so clearly shown as to leave no doubt 

 of their practical identity with those of living birds. 



It is therefore evident that birds with feathers began to 

 be developed as early as (perhaps even earlier than) the 

 membranous-winged reptiles (Pterodactyles), and that these 

 two groups of flying vertebrates began on two opposite 

 principles. The birds must have started on the principle of 

 condensation and specialisation of the fore limb exclusively 

 for flight by means of feathers ; the other by the extension 

 of one reptilian digit to support a wing-membrane, while 

 reserving the others probably for suspension, as in the case 

 of the thumb of the bats. 



The Marvel and Mystery of Feathers 



Looking at it as a whole, the bird's wing seems to me 

 to be, of all the mere mechanical organs of any living thing, 

 that which most clearly implies the working out of a pre- 

 conceived design in a new and apparently most complex 



