Eucoelomate

Eucoelomate
("yoo-see-lem-ate") A triploblastic organism that has a true coelom (fluid-filled body cavity) that surrounds the gut and is lined on both sides with 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.

The eucoelom in arthopods  and most molluscs  is reduced and t heir principal body cavity is the  hemocoel  of an open cirulatory system  often derived from the blastocoel.

Examples:

 * Annelida
 * Echinoderms
 * Molluscs
 * Arthopoda (marine and terrestrial)
 * Chordates

See also: Development & Tissues