He describes the membranes with which some of the mollusca envelope their eggs, mentions the changes through which insects pass before they acquire the perfect state, and speaks with tolerable accuracy of the economy of bees and wasps. He states, however, that the former make wax from flowers, but gather their honey from a substance which falls from the air upon trees. The eggs of tortoises, he says, are hard, like those of birds, and are deposited in the ground. His remarks on those of lizards and the crocodile are also correct. He states accurately that some serpents bring forth their young enclosed in a soft membrane, which they afterwards burst; but that sometimes the little animals escape from the egg internally, and are produced free. Other serpents, he observes, bring forth eggs cohering in the form of a necklace. On the eggs of birds his observations are nearly as correct as those which we find in books at the present day. He was acquainted with their general structure, and the development of the chick, which he minutely describes. He remarks of the cuckoo, that it is not a changed hawk, as some have asserted; that, although certain persons have alleged that its young have never been seen, it yet certainly has young; that, however, it does not construct a nest, but deposites its eggs in the nest of other birds, after eating those which it finds there. He remarks that the cartilaginous fishes are viviparous, but that the other species bring forth eggs, and states correctly that they have no alantoid membrane. He then passes to the cetacea, with which he seems to be nearly as well acquainted as modern naturalists, and reverts to the oviparous fishes, respecting which he presents numerous details. He maintains, however, that the eel is produced spontaneously, and that no person had ever detected eggs or milt in it. Having discussed the subject of generation, he proceeds, in the eighth book, to treat of the food and actions of animals, their migrations, and other circumstances. The ninth consists of a multitude of topics without any direct relation to each other, but apparently treated as they had successively presented themselves to the author. Thus, at the commencement we find remarks on the peculiarities of disposition observed in the males and females of different animals, the combats of hostile species, the actions of animals, nidification, generation, and other matters. Several species of different classes are then described, such as the kingfisher, the black-bird, the cuckoo, the marten, eagles, owls, fishes, insects, and quadrupeds.