madreporite
takes in water for water vascular system
ring canal
water from madreporite to radial canal
radial canal
water from ring canal through arms to ampullae
ampullae
water from radial canal to tube feet
tube feet
water taken from the water vascular system for locomotion
mouth
on the bottom
anus
on the top
stomach
around the ring canal
tube feet
(bottom) locomotion
gonads
(middle)
digestive gland
(top)