e is dropped the embryo seed,
And quickly vegetates a vital breed.

We cannot wonder that such organisms were long regarded as belonging to
the vegetable kingdom. The cups which terminate the branches contain,
however, an animal structure, resembling a small Sea Anemone, and
possessing arms which capture the food by which the whole colony is
nourished. Some of these cups, moreover, differ from the rest, and
produce eggs. These then we might be disposed to term ovaries. But in
many species they detach themselves from the group and lead an
independent existence. Thus we find a complete gradation from structures
which, regarded by themselves, we should unquestionably regard as mere
organs, to others which are certainly separate and independent beings.

[Illustration: Fig. 2.--Bougainvillea fruticosa; natural size. (After
Allman.)]

Fig. 2 represents, after Allman, a colony of Bougainvillea fruticosa of
the natural size. It is a British species, which is found growing on
buoys, floating timber, etc., and, says Allman, "When in health and
vigour, offers a spectacle unsurpassed in interest by any other
species--every branchlet crowned by its graceful hydranth, and budding
with Medusae in all stages of development (Fig. 3), some still in the
condition of minute buds, in which no trace of the definite Medusa-form
can yet be detected; others, in which the outlines of the Medusa can be
distinctly traced within the transparent ectotheque (external layer);
others, again, just casting off this thin outer pellicle, and others
completely freed from it, struggling with convulsive efforts to break
loose from the colony, and finally launched forth in the full enjoyment
of their freedom into the surrounding water. I know of no form in which
so many of the characteristic features of a typical hydroid are more
finely expressed than in this beautiful species."

[Illustration: Fig. 3.--Bougainvillea fruticosa; magnified to show
development.]

Fig. 4 represents the Medusa or free form of this beautiful species.

[Illustration: Fig. 4.--Bougainvillea fruticosa, Medusa-form.]

If we pass to another great group of Zoophytes, that of the
Jelly-fishes, we have a very similar case. For our first knowledge of
the life-history of these Zoophytes we are indebted to the Norwegian
naturalist Sars. Take, for instance, the common Jelly-fish (Medusa
aurita) (Fig. 5) of our shores.

The egg is a pear-shaped body (_1_), covered with fine hairs, b