2. All birds have claws and many divisions of the foot; in most of them the toes are quite separate; but the swimmers have their feet covered with a web, but even these have distinct and jointed toes. All birds that fly high in the air have four toes; and, generally, these are placed three forwards, and one backward, like a heel; a few birds have two toes turned forwards and two backwards, as the bird called jynx.[37] This bird is somewhat larger than the spize,[38] and is variegated in appearance. The formation of its toes is peculiar, and so is that of its tongue, which is like a serpent's. This it can project from its mouth, as much as the width of four fingers, and draw it in again. Like a snake it can turn its neck quite round, whilst the rest of its body is perfectly still. It has large claws, like those of the colius,[39] and it hisses with its voice. [37] Jynx torquilla, wry-neck. [38] Fringilla, finch. [39] Perhaps Corvus galgulus. 3. Birds have a mouth, but its construction is peculiar, for they have neither lips nor teeth, but a beak, and neither ears nor nostrils, but only passages for these organs, for the nostrils in the beak, and for the ears in the head. They have two eyes like other animals, without eyelashes; when heavy with sleep, they close their eyes with the lower eyelid; and all possess a nictitating membrane, which closes the eye. The owl-like birds also use the upper eyelid. The same is the nature of the scaly animals, as the saurians, and others of this class; all of them close their eyes with the lower eyelid, but they do not all wink like birds. Again, birds have neither scales nor hair, but feathers; all the feathers have a stem. 4. Birds have no tail, but a rump; in birds with long legs, or palmated feet, this is short, in others it is large. These last, when they fly, keep their legs close to the body, but the others stretch them out behind them. All birds have a tongue, but this differs in various kinds: some have it large, others small. Next after man, some birds articulate words better than any other animals; this is particularly the case with those with broad tongues. No oviparous animal has an epiglottis on its trachea: but it can close and open the passage, so as to prevent any heavy thing finding its way into the lungs. 5. Some tribes of birds have spurs; this is never the case with those which have crooked claws. Those with crooked claws are more active in flight; those which have spurs, are heavier in their make. 6. Some birds have a crest, mostly formed of erect feathers; the domestic fowl, alone, is peculiar, for its crest is neither flesh, nor very unlike flesh. CHAPTER IX.