#water vascular system

• Ambulacral — Belonging to the ambulacrum, relating to the ambulacrum or to the water vascular system of echinoderms (such as starfish or sea urchins). The term describes anatomical elements, perforated zones of the exoskeleton, or flexible hydraulic feet utilized by these marine organisms for locomotion, fixation, respiration, and food capture in their natural environment.
• Ambulacrum — An anatomical formation specific to echinoderms, represented by a groove, a perforated zone, or a radial band along the body, through whose openings the hydraulic (ambulacral) feet protrude. Also, the term can broadly designate the entire water vascular system, being the core structural element that differentiates this class of marine invertebrates within the animal kingdom.