All those animals that are viviparous produce their young with the head first, the young animal about the time of yeaning turning itself round in the womb, where at other times it lies extended at full length. Quadrupeds during the time of gestation have the legs extended, and lying close to the belly; while, on the other hand, man is gathered up into a ball, with the nose between the knees. With reference to moles, of which we have previously[1] spoken, it is supposed that they are produced when a female has conceived, not by a male, but of herself only. Hence it is that there is no vitality in this false conception, because it does not proceed from the conjunction of the two sexes; and it has only that sort of vegetative existence in itself which we see in plants and trees.

(65.) Of all those which produce their young in a perfect state, the swine is the only one that bears them in considerable numbers as well; and, indeed, several times in the year a thing that is contrary to the usual nature of animals with a solid or cloven hoof.