Based on formation, the coelom is classified into two types: Schizocoelom and Enterocoelom.
Schizocoelom – It is present in the protostomes. The body cavity or coelom originates from the splitting of mesoderm. One part attaches to ectoderm and the other surrounds the endoderm. The space between them develops into the coelom. The blastopore forms mouth.
Examples of schizocoelous animals – Arthropoda and Annelida.
Enterocoelom – It is present in the deuterostomes. The coelom is formed from the fusion of the internal outgrowths of the archenteron, that pinches off and fuses together to form coelom lined by mesoderm.
Examples of Enterocoelom animals – Chordates and Echinodermata.