the type of body cavity found in all echinoderms is a true
They are true coelomates in which the coelom is lined both on the inside of the body wall as well as around the gut by mesoderm. Animals with a true coelom also have mesenteries, which suspend the body organs within the coelom.Animals higher to round worms such as annelids, arthropods, mollusks, echinoderms and chordates fall in this category. Tue coelomates are of the following types.(i) Schizocoelomates are true coelomates in which the body cavity originates by splitting of mesodermal tissue at the time of gastrulation.. Pseudocoelomates, in which a body cavity exists in addition to alimentary canal, but it is lined by mesoderm only on the outer body wall side and not around the gut. Examples are round worms (Nemathelminthes) and some minor phyla grouped under Aschelminthes. 3. Coelomates or Eucoelmates.