2. There are, however, some variations even among birds; for the male sometimes unites with the female as she sits upon the ground, as the bustard and domestic fowl: in others, the female does not sit upon the ground, as the crane; for in these birds the male unites with the female standing up; and the act is performed very quickly, as in sparrows. Bears lie down during the act of intercourse, which is performed in the same manner as in those that stand on their feet, the abdomen of the male being placed upon the back of the female: in the hedgehogs, the abdomens of both sexes are in contact. 3. Among the large animals, the roe-deer seldom admits the stag, nor the cow the bull, on account of the hardness of the penis; but the female receives the male by submission. This has been observed to take place in tame deer. The male and female wolf copulate like dogs. Cats do not approach each other backwards, but the male stands erect, and the female places herself beneath him. The females are very lascivious, and invite the male, and make a noise during the intercourse. 4. Camels copulate as the female is lying down, and the male embraces and unites with her, not backwards, but like other animals. They remain in intercourse a whole day. They retire into a desert place, and suffer no one to approach them but their feeder. The penis of the camel is so strong, that bowstrings are made of it. Elephants also retire into desert places for intercourse, especially by the sides of rivers which they usually frequent. The female bends down and divides her legs, and the male mounts upon her. The seal copulates like retromingent animals, and is a long while about it, like dogs. The males have a large penis. CHAPTER III. 1. Oviparous quadrupeds with feet copulate in the same manner: in some, the male mounts upon the female, like viviparous animals, as in the marine and land turtle, for they have an intromittent organ by which they adhere together, as the trygon and frog, and all such animals. 2. But the apodous long animals, as serpents and murænæ, are folded together, with the abdomens opposite, and serpents roll themselves together so closely, that they seem to be but one serpent with two heads. The manner of the whole race of saurians is the same, for they unite together in the same kind of fold. CHAPTER IV. 1. All fish, except the flat selache, perform the act of intercourse by approaching each other with their abdomens opposite: but the flat fish, with tails, as the batos, trygon, and such like, not only approach each other, but the male applies his abdomen to the back of the female, in all those in which the thickness of the tail offers no impediment. But the rhinæ, and those which have a large tail, perform the act by the friction of their abdomens against each other, and some persons say that they have seen the male selache united to the back of the female, like dogs.