Classification of Animal Kingdom on basis of Nature of coelom
Coelom refers to a fluid filled body cavity present between the body wall and the intestine and is lined with mesodermal epithelium. It is present in bilaterally symmetrical
Organisms are classified into three categories based on the nature of coelom:
1. Acoelomates – Acoelomates are those which do not possess any coelom.
2. Pseudo-coelomates – Pseudo-coelomates are those which possess coelom but not lined by mesoderm. Instead mesoderm is present as scattered pouches.
3. True coelomates or Entero-coelomates – Coelomates are those which possess a proper fluid filled body cavity lined by mesoderm.
E.g: annelids, molluscs, arthropods, echinoderms, hemichordates and chordates.