PPT Slide
- On the aboral surface is the opening of the water vascular system the madreporite (=sieve plate)
- Water enters the madreporite and goes through the stone canal canal to the ring canal
- Water then passes through a radial canal extending into each arm
- All along the length of these canals are lateral canals that terminate in a bulb-like structures called ampullae equipped with tube feet
- Tube feet line the grooves on the oral surface - ambulacral grooves