Diversity in Living Organisms — Science STD 9 — Question

Coelom is the body cavity present between the body wall and the gut wall. Presence or absence of coelom is very important basis of classification. Example:

1. Acoelomate: Coelom is absent, e.g., poriferous, coelentrates, ctenophores and flatworms.
2. Pseudocoelomate: The body cavity is not lined by mesoderm instead it is present as scattered pouches in between mesoderm and endoderm. e.g., round worms.
3. Eucoelomate: Presence of true coelom. True coelom is of two types.

• Schizocoelom Develops by splitting up of mesoderm.
• Enterocoelom The mesoderm arises from wall of embryonic gut.