. A book of birds. Birds. 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 t
. A book of birds. Birds. 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. Plea
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Keywords: ., bookcentury1900, bookdecade1900, booksubjectbirds, bookyear1908
