The bulb of the olfactory nerve is covered by
certain cerebral parts, in man, monkeys, and the
phocse ; but in the generality of mammiferous
animals and birds, it lies, altogether, anterior to
the cerebral hemispheres; nevertheless, no one
concludes that they, therefore, want the front
lobes. On the other hand, it is a great error to
assume with M. Serres *, as an axiom, that — " The
encephalon of all vertebral animals is constructed
after one uniform type, and with the same ele-
ments," or with M. Cuvierf, to say that — "The
brains of the mammalia have the same parts as
that of man."

In principle, I maintain that the cerebral he-
mispheres of animals are composed of a greater
or smaller number of parts, as different from each
other as the optic from the auditory nerves. The
existence of the posterior lobes of animals is not
to be doubted, seeing that the ganglion, out of
which they proceed (thalamus), is found in them.
