Wiktionary
radial canal
n. 1 any of the numerous minute canals lined with choanocytes which radiate from the paragastric cavity in some sponges and end just below the surface of the sponge 2 any of the canals extending through the substance of the umbrella from the gastric cavity to the marginal circular canal in jellyfish 3 a tube extending outward along each ambulacral area from the circumoral canal in most echinoderms