radial canal

from Wiktionary, Creative Commons Attribution/Share-Alike License.

• noun 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
• noun any of the canals extending through the substance of the umbrella from the gastric cavity to the marginal circular canal in jellyfish
• noun a tube extending outward along each ambulacral area from the circumoral canal in most echinoderms