radial canal

Short definition from Wiktionary

Noun

1. 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. 2
   any of the canals extending through the substance of the umbrella from the gastric cavity to the marginal circular canal in jellyfish
3. 3
   a tube extending outward along each ambulacral area from the circumoral canal in most echinoderms