File:Sea urchin Tube feet extended past the Spines.jpg - Wikipedia
Unique system of photoreceptors in sea urchin tube feet | PNAS
DK Nature: Echinoderms
Plasticity in the purple sea urchin (Strongylocentrotus purpuratus): Tube feet regeneration and adhesive performance - ScienceDirect
Oregon Coast Aquarium - Happy #Tubesday! Purple sea urchins have tube feet that aid in movement, feeding, and respiration. Sea urchins also possess unique mouth parts, referred to as an Aristotle's lantern.
Sea Urchin Regeneration May Help Us Understand Aging – Biomedical Beat Blog – National Institute of General Medical Sciences