“We argue that the entire adult sea urchin can act as a huge compound eye, and that the shadow that is cast by the animal’s opaque skeleton over the light-sensitive cells can give it directional vision,” says Dupont.
Details appear in a newly published study by Dupont and his colleagues:
“Unique system of photoreceptors in sea urchin tube feet,” Esther M Ullrich-Lüter, Sam Dupont, Enrique Arboledac, Harald Hausend, and Maria Ina Arnonec, PNAS 2011/04/26 .