[Illustration: Fig. 34. The Adjutant Bird. Showing the foot resting from heel to toe upon the ground.] Already, then, we see that the bird is using the same bones as a reptile, though he uses them in a different way; and besides these resemblances between the skeletons of birds and reptiles there are two special ones easy enough for us to understand. We saw in the snakes and the lizards that they have a separate bone (9, Figs. 23 and 26) joining the lower jaw on to the head; now you will find this same bone in the sparrow and in all birds (see Fig. 33), but in quadrupeds this bone is not to be found, the part representing it being changed into one of the bones of the ear. Again, the sparrow’s skull is joined to his backbone by a single half-moon-shaped knob, which fits into a groove in the first joint or vertebra. This also we find in reptiles, while all higher animals have two such knobs, so that although they can nod the head upon these, they cannot turn it upon them, and consequently the first joint turns with the skull upon the second vertebra. These, then, are some of the reasons why Professor Huxley tells us that though frogs and reptiles look in many ways so like each other, yet in truth the frogs must be grouped with the gill-breathing and fish-like animals;[88] while the cold-blooded reptiles, when we come to look closely into them, are linked with such different looking creatures as the bright and merry birds.[89] But we have also another and stronger reason for thinking that reptiles and birds are distant connections; for in those far bygone times (see p. 92), when the huge land-lizards browsed upon the trees, the birds living among them were much more like them in many ways than they are now. From their skeletons and feathers which we find, we know that the strange land birds[90] which then perched on the trees had not a fan-shaped tail made of feathers, growing on one broad bone as our birds have now (_p_, Fig. 33), but they had _a long tail of many joints like lizards_, only that each joint carried a pair of feathers, and like lizards too they had _teeth in their jaws_, which no living bird has. They must have been poor flyers at best, these earliest known birds, for their wings were small and the fingers of their hand were separate more like lizard’s toes, two of them at least having claws upon them, while their long hanging tail must have been very awkward compared to the fan-shaped tail they now wear. For some time they were the only birds we know of, but later on we come upon the bones of water-birds[91] telling the same story. For some about the size of small gulls,[92] though they flew with strong wings and had fan-shaped tails, still had teeth in their horny jaws, set in sockets like those of the crocodile, while their backbones had joints like those of fishes rather than birds; and with them were other and wingless birds[93] rather larger than our swans, but more