Cephalization is the
tendency of concentration the
nervous command central structures
in there are grouping neurons
(i.e, brain ganglia formation).
Evolutionarily cephalization process
begins the appearance of
(group of neurons) platyhelminthes
and reaches apex in vertebrates,
with a cranial to protect the
-developed brain.

With lateral the body can
divided into lateral , superior,
inferior, anterior posterior. These
portions be integrated and
in some manner this
need stimulated appearance of
ganglial and of beings a
head, a extremity of the
body where the central
command and sensory organs
are .