Echinoderms

Who are they?

A strictly marine group of invertebrates including five major classes (Crinoidea, Asteroidea, Ophiuroidea, Holothuroidea and Echinoidea) with over 6000 species.

Characteristics

• Radially symmetrical

• No head, brain or tail end

• Calcareous skeleton of plates under skin

• Water vascular system

• Tube feet

• Ability to regenerate body parts