There was something rather curious lurking the bottom of the Elmhurst Public Library’s aquarium. Upon further inquiry I found it was a brittle starfish. Here’s some interesting factoids:
Its five equal segments contain a duplicate set of various internal organs. They have no heart, brain, nor eyes, but some brittle stars seem to have light sensitive parts on their arms. Their mouth is situated on the underside and their anus on top. It can regenerate and grow a new arm when they lose on to a hungry predator.