A BOOK OF BIRDS 



Well, one of two courses is open to us. Either we must believe 

 that birds were, as used to be held, specially created ; or that they 

 have inherited these common characters from a common ancestor, 

 which must have been some sort of a reptile. And in support of the 

 reasonableness of this latter view we may appeal to the evidence 

 which the rocks have preserved for us in the shape of the fossil remains 

 of ancestral birds. In these we have still further and more striking 

 proof of the descent of birds from reptiles. 



The earliest fossil bird yet discovered is that known as the 

 Archaeopteryx, and this differed from all other birds in one or two 



very important particulars. In 

 each case they serve to bridge 

 the gap between the reptiles 

 and the birds, though it must 

 be admitted many other links 

 are desirable to make the chain 

 absolutely complete. In the first 

 place, instead of the horny 

 sheaths which cover the beak 

 of living birds, we find the jaws 

 were provided with teeth, set in 

 sockets like those of the croco- 

 dile ; while in the second, the 

 tail was of great length, being 

 made up of a long row of bones, 

 as in the tail of reptiles. Each 

 bone supported a pair of feathers, as may be seen in our illustra- 

 tion, so that in this respect it was neither like that of the reptile nor 

 of the typical bird. In the latter, the tail is apparently fashioned after 

 a very different manner ; but in examining this it must be remembered 

 that what is commonly called the '' tail " is really only the outward 

 and visible sign of this appendage, for the feathers alone no more 

 make the tail than does the hair the tail of a dog. 



When we come, then, to examine the arrangement of the tail- 

 feathers, we find that they are set fan-wise about a plate of bone, 

 the last of a series of the eight separate tail-bones which form the 

 termination of the backbone. And if we examine this bony plate 



Fig. 3.— The First Known Bird, from 

 Restoration by W. P. Pycraft. 



