Sea urchins are part of the phylum
Echinodermata. Their average size is
about 1.2 - 3.9 inches, although it
depends on the species. Sea Urchins
have radial symmetry, that means they
can be divided into 5 equal parts. The majority
of sea urchins have the colors either black, brown,
purple, red, or green. Sea urchins have five rows
of paired tube feet along the bottom part of their
body. They have spikes along their body to
protect their soft innershell. Some species can
have venom in their spikes.
