rity, world
without end!

Sixthly, The cold-blooded animals, as the fish-tribes, which are furnished
with but one ventricle of the heart, and with gills instead of lungs, and
with fins instead of feet or wings, bear a great similarity to each other;
but they differ, nevertheless, so much in their general structure from the
warm-blooded animals, that it may not seem probable at first view, that the
same living filament could have given origin to this kingdom of animals, as
to the former. Yet are there some creatures, which unite or partake of both
these orders of animation, as the whales and seals; and more particularly
the frog, who changes from an aquatic animal furnished with gills to an
aerial one furnished with lungs.

The numerous tribes of insects without wings, from the spider to the
scorpion, from the flea to the lobster; or with wings, from the gnat and
the ant to the wasp and the dragon-fly, differ so totally from each other,
and from the red-blooded classes above described, both in the forms of
their bodies, and their modes of life; besides the organ of sense, which
they seem to possess in their antennae or horns, to which it has been
thought by some naturalists, that other creatures have nothing similar;
that it can scarcely be supposed that this nation of animals could have
been produced by the same kind of living filament, as the red-blooded
classes above mentioned. And yet the changes which many of them undergo in
their early state to that of their maturity, are as different, as one
animal can be from another. As those of the gnat, which passes his early
state in water, and then stretching out his new wings, and expanding his
new lungs, rises in the air; as of the caterpillar, and bee-nymph, which
feed on vegetable leaves or farina, and at length bursting from their
self-formed graves, become beautiful winged inhabitants of the skies,
journeying from flower to flower, and nourished by the ambrosial food of
honey.

There is still another class of animals, which are termed vermes by
Linnaeus, which are without feet, or brain, and are hermaphrodites, as
worms, leeches, snails, shell-fish, coralline insects, and sponges; which
possess the simplest structure of all animals, and appear totally different
from those already described. The simplicity of their structure, however,
can afford no argument against their having been produced from a living
filament as above contended.

Last of all the various tribes