to distinct genera, have many features in common, and hence are grouped
together in an assemblage which is called a family. More distant
resemblances connect the lobster with the prawn and the crab, which are
expressed by putting all these into the same order. Again, more remote,
but still very definite, resemblances unite the lobster with the
woodlouse, the king crab, the water flea, and the barnacle, and
separate them from all other animals; whence they collectively
constitute the larger group, or class, 'Crustacea'. But the
'Crustacea' exhibit many peculiar features in common with insects,
spiders, and centipedes, so that these are grouped into the still
larger assemblage or "province" 'Articulata'; and, finally, the
relations which these have to worms and other lower animals, are
expressed by combining the whole vast aggregate into the sub-kingdom of
'Annulosa'.

If I had worked my way from a sponge instead of a lobster, I should have
found it associated, by like ties, with a great number of other animals
into the sub-kingdom 'Protozoa'; if I had selected a fresh-water polype
or a coral, the members of what naturalists term the sub-kingdom
'Coelenterata', would have grouped themselves around my type; had a
snail been chosen, the inhabitants of all univalve and bivalve, land
and water, shells, the lamp shells, the squids, and the sea-mat would
have gradually linked themselves on to it as members of the same
sub-kingdom of 'Mollusca'; and finally, starting from man, I should have
been compelled to admit first, the ape, the rat, the horse, the dog,
into the same class; and then the bird, the crocodile, the turtle, the
frog, and the fish, into the same sub-kingdom of 'Vertebrata'.

And if I had followed out all these various lines of classification
fully, I should discover in the end that there was no animal, either