What is the relationship between germinal layers and the formation of body cavity in case in of coelomate, acoelomates and pseudocoelomates ?

Explanation

(a) In acoelomates, either there is no mesoderm and coelom between entoderm and endoderm e.g. sponges and coelenterates, or a solid mesodermal parenchyma is is between the two e.g. flatworms. (b) In pseudocoelomates e.g. roundworms, coelomic, pouches are scattered in the mesoderm but no continuous cavity is present. (c) In eucoelomates, a mesodermal-lined body cavity, called coelom, is present between the body wall and gut wall. It is formed either by splitting of mesoderm e.g. schizocoelic coelom in annelids, arthropods and molluscs, or from enterocoelic pouches of archenteron e.g. enterocoelic coelom in echinoderms, hemichordates and chordates.