Adult echinoderms, along
cnidarians, are the that present
radial , i.e., their body
are distributed around
center. Theradial symmetry
echinoderms however is secondary
radial symmetry, their larval stage
bilateral symmetry and radial
pattern appears in adult individuals
( are some few echinoderms
with lateral ). All other
animals lateral symmetry with
of poriferans (no is
defined for ).

Echinoderms do not
cephalization and they a diffuse
network nerves and neurons of
a neural around the mouth of
radial nerves ramify to follow
pentaradial structure of body.