Intraembryonic Coelom

Some articles on coelom:

Body Cavity - Coelom
... A coelom is a cavity lined by an epithelium derived from mesoderm ... Organs formed inside a coelom can freely move, grow, and develop independently of the body wall while fluid cushions and protects them from shocks ... Arthropods and mollusks have a reduced (but still true) coelom ...