As to the parts

internal and external that all animals are
furnished withal, and further as to the senses, to voice, and sleep,
and the duality sex, all these topics have now been touched upon. It
now remains for us to discuss, duly and in order, their several
modes of propagation.

These modes are many and diverse, and in some respects are like,
and in other respects are unlike to one another. As we carried on
our previous discussion genus by genus, so we must attempt to follow
the same divisions in our present argument; only that whereas in the
former case we started with a consideration of the parts of man, in
the present case it behoves us to treat of man last of all because
he involves most discussion. We shall commence, then, with testaceans,
and then proceed to crustaceans, and then to the other genera in due
order; and these other genera are, severally, molluscs, and insects,
then fishes viviparous and fishes oviparous, and next birds; and
afterwards we shall treat of animals provided with feet, both such
as are oviparous and such as are viviparous, and we may observe that
some quadrupeds are viviparous, but that the only viviparous biped
is man.