What is the system that permits movement and fixation to echinoderms?
The system that allows movement and fixation to substrates in echinoderms is known as the ambulacral system. In these animals water enters by a structure called madreporite, passes by channels and reaches the ambulacral feet in the undersurface of the body. In the ambulacral region in contact with the substrate, there are tube feet filled and emptied by water therefore acting as suckers