1. One of the five radial areas on the undersurface of the starfish and similar echinoderms, from which the tube feet are protruded and withdrawn: These ambulacra usually have rows of locomotive suckers or tentacles, which protrude from regular pores so they can move (walk) around.
2. The suckers on the feet of mites: Mites use ambulacra as a means of walking on and hanging on to their victims.