CHAP. 87. (68.)—ANIMALS WHICH ARE BORN OF BEINGS THAT
HAVE NOT BEEN BORN THEMSELVES—ANIMALS WHICH ARE BORN
THEMSELVES BUT ARE NOT REPRODUCTIVE—ANIMALS WHICH
ARE OF NEITHER SEX.
Some animals, again, are engendered of beings that are not
engendered themselves, and have no such origin as those above
mentioned, which are produced in the spring, or at some stated
period of the year. Some of these are non-productive, the salamander, for instance, which is of no sex, either male or female; a distinction also, which does not exist in the eel and
the other kinds that are neither viviparous nor oviparous. The
oyster also, as well as the other shell-fish that adhere to the
bottom of the sea or to rocks, are of neither sex. Again, as to
those animals which are able to engender of themselves, if they
are looked upon as divided into male and female, they do engender something, it is true, by coupling, but the produce is imperfect, quite dissimilar to the animal itself, and one from which
nothing else is reproduced; this we find to be the case with
flies, when they give birth to maggots. This fact is better illustrated by the nature of those animals which are known as insects; a subject, indeed, very difficult of explanation, and one
which requires to be treated of in a Book [Note] by itself. We will,
therefore, proceed for the present with our remarks upon the
instincts of the animals that have been previously mentioned.