The Water-Vascular System
Coelom separated in two parts: perivisceral coelom = axocoel (circulation and excretion; papulae serve as “gills”) and hydrocoel (locomotion, feeding)
Hydrocoel = Water-vasuclar system: ring canal, radial canals, lateral canals, ampullae, tube feet
Water intake: madreporite, through stone canal into ring canal
Tiedemann’s bodies: filter vascular system with amoebocytes