4. The elephant has a penis like a horse, but small and less in proportion to the size of its body; its testicles are not external but internal, and near the kidneys, wherefore also the work of copulation is quickly performed. The female has the pudendum in the same position as the udder of the sheep, and when excited with desire, it is lifted up outwards, so as to be ready for copulation with the male; and the orifice of the pudendum is very wide. Most animals have the penis in the same direction, but some are retromingent, as the lynx, lion, camel, and hare. In some males, as I have said, the direction of the penis is different, but all females are retromingent, for even in the female elephant the pudendum is placed under the thighs, as in other animals. 5. The penis is very different in different animals, for in some it is cartilaginous and fleshy, as in man; the fleshy part does not swell, but the cartilaginous portion is erected; in others it is sinewy, as the camel and the stag; in others it is bony, as the fox and the wolf, the weasel and the martin, for the martin also has a bony penis. 6. Again, man being a perfect animal, has the upper part of his body less than the lower part; the contrary is the case with other sanguineous animals: by the upper portion of his body we mean the portion of his body from the head to the anus, and by the lower, the parts from hence downwards. In those animals which have feet the hind leg is the lower part of the body in point of size; and in those without legs, the same relation is observed in their various kinds of tails. Such is the nature of perfected animals, but they differ in the development of their parts. Man in the young state has the upper part of his body greater than the lower; but as he grows the proportion of his parts changes, wherefore also he is the only animal which does not move in the same way when young and when grown up, for at first a child crawls like a four-footed animal. 7. Some animals grow in the same proportion throughout, as the dog--others when they are first born have their upper part proportionally less than the lower, but as they approach maturity, the upper parts increase in size, as in the lophuri, for in these animals the part from the hoof to the haunch never grows after their birth. 8. There is a great difference in the teeth of animals, both among themselves and from the human type; all viviparous and sanguineous quadrupeds have teeth; some have teeth in both jaws, which others have not; this is the first distinction. Those which have horns do not possess teeth in both jaws, for they have no front teeth in the upper jaw. There are others, as the camel, which, though it has no horns, has not teeth in the upper jaw.