in either air or water, as, for instance, the sea-nettle and the
oyster. And of creatures that live in the water some live in the
sea, some in rivers, some in lakes, and some in marshes, as the frog
and the newt.

    Of animals that live on dry land some take in air and emit it,
which phenomena are termed 'inhalation' and 'exhalation'; as, for
instance, man and all such land animals as are furnished with lungs.
Others, again, do not inhale air, yet live and find their sustenance
on dry land; as, for instance, the wasp, the bee, and all other
insects. And by 'insects' I mean such creatures as have nicks or
notches on their bodies, either on their bellies or on both backs
and bellies.

    And of land animals many, as has been said, derive their
subsistence from the water; but of creatures that live in and inhale
water not a single one derives its subsistence from dry land.

    Some animals at first live in water, and by and by change their
shape and live out of water, as is the case with river worms, for
out of these the gadfly develops.

    Furthermore, some animals are stationary, and some are erratic.
Stationary animals are found in water, but no such creature is found
on dry land. In the water are many creatures that live in close
adhesion to an external object, as is the case with several kinds of
oyster. And, by the way, the sponge appears to be endowed with a
certain sensibility: as a proof of which it is alleged that the
difficulty in detaching it from its moorings is increased if the
movement to detach it be not covertly applied.

    Other creatures adhere at one time to an object and detach
themselves from it at other times, as is the case with a species of
the so-called sea-nettle; for some of these creatures seek their
food in the night-time loose and unattached.

    Many creatures are unattached but motionless, as is the case with
oysters and the so-called holothuria. Some can swim, as, for instance,
fishes, molluscs, and crustaceans, such as the crawfish. But some of
these last move by walking, as the crab, for it is the nature of the
creature, though it lives in water, to move by walking.

    Of land animals some are furnished with wings, such as birds
and bees, and these are so furnished in different ways one from
another; others are furnished with feet. Of the animals that are
furnished with feet some walk, some creep, and some wriggle. But no
creature is able only to move by flying, as the fish is able only to
swim, for the animals with leathern wings can walk; the bat has feet
and the seal has imperfect feet.

    Some birds have feet of little power, and are therefore called
Apodes. This little bird is powerful on the wing; and, as a rule,
birds that resemble it are weak-footed and strong winged, such as
the swallow and the drepanis or (?) Alpine swift; for all these
birds resemble one another in their habits and in their plumage, and
may easily be mistaken one for another. (The apus is to be seen at all
seasons, but the drepanis only after rainy weather in summer; for this
is the time when it is seen and captured, though, as a general rule,
it is a rare bird.)

    Again, some animals move by walking on the ground as well as by
swimming in water.

    Furthermore, the following differences are manifest in their
modes of living and in their actions. Some are gregarious, some are
solitary, whether they be furnished with feet or wings or be fitted
for a life in the water; and some partake of both characters, the
solitary and the gregarious. And of the gregarious, some are
disposed to combine for social purposes, others to live each for its
own self.

    Gregarious creatures are, among birds, such as the pigeon, the
crane, and the swan; and, by the way, no bird furnished with crooked
talons is gregarious. Of creatures that live in water many kinds of
fishes are gregarious, such as the so-called migrants, the tunny,
the pelamys, and the bonito.

    Man, by the way, presents a mixture of the two characters, the
gregarious and the solitary.

    Social creatures are such as have some one common object in view;
and this property is not common to all creatures that are
gregarious. Such social creatures are man, the bee, the wasp, the ant,
and the crane.

    Again, of these social creatures some submit to a ruler, others
are subject to no governance: as, for instance, the crane and the
several sorts of bee submit to a ruler, whereas ants and numerous
other creatures are every one his own master.

    And again, both of gregarious and of solitary animals, some are
attached to a fixed home and others are erratic or nomad.

    Also, some are carnivorous, some graminivorous, some omnivorous:
whilst some feed on a peculiar diet, as for instance the bees and
the spiders, for the bee lives on honey and certain other sweets,
and the spider lives by catching flies; and some creatures live on
fish. Again, some creatures catch their food, others treasure it up;
whereas others do not so.