Considering the example of
it is observed that
makes the increasing of
complexity of the organisms be
accompanied by convergence nervous
cells to special for controlling
and commanding: ganglia and the
brain. simple invertebrates, like
cnidarians, nervous cells are not
but they are found
in the body. In
a beginning of
cephalization the anterior ganglion
concentrating is already
verified. In and arthropods the
existence a cerebral ganglion is
. In cephalopod molluscs the
is even greater and
brain commands the nervous .