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.