In holothuroids, the podia may be reduced or absent and the madreporite opens into the body cavity so that the circulating liquid is coelomic fluid rather than sea water.
12.
The animals apparently did not have an anus, but a madreporite was on the upper surface, surrounded by what appear to be genital pores for the release of gametes.
13.
According to a definition at biology-online . org, a Madreporic Plate ( also called a madreporite ) is a perforated plate in echinoderms, through which water is admitted to the ambulacral tubes.
14.
At this stage they become radially symmetrical, each one having a single central plate, a madreporite plate, five radial and five interradial plates, and five terminal plates which are the first stage in the development of the arms.
