radial canal

1 :  one 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 :  one of the canals extending through the substance of the umbrella from the gastric cavity to the marginal circular canal in jellyfishes

3 :  a tube extending outward along each ambulacral area from the circumoral canal in most echinoderms