madreporite

The madreporite, also known as the madreporic body, is a perforated or porous structure found at the end of the stone canal in echinoderms. This sieve plate is a crucial component of the water-vascular system, which is characteristic of echinoderms and functions in the movement of tube feet. The madreporite's primary role is to take in water from outside the body, which then flows through the system to extend the tube feet. In some echinoderms, like many holothurians, the madreporite is located internally and takes in fluid from the body cavity. The structure and location of the madreporite can vary among different groups of echinoderms.12