Noun
a cavity in the mesoderm of an embryo that gives rise in humans to the pleural cavity and pericardial cavity and peritoneal cavity
Source: WordNetAnimal Evolution: Interrelationships of the Living Phyla. 3rd ed. Oxford, UK: Oxford University Press, 2012, p. 78 Haemal and perihaemal systems are derived from the coelom and form an open and reduced circulatory system. Source: Internet
Aside from the water vascular system, echinoderms have a haemal coelom (or haemal system, the "haemal" being a misnomer), a perivisceral coelom, a gonadal coelom and often also a perihaemal coelom (or perihaemal system). Source: Internet
Eggs and sperm are released into the coelom, and sperm exit into the water through pores in the tips of some of the tentacles, and then are captured by the feeding currents of zooids that are producing eggs. Source: Internet
Egg brooding is quite common and usually takes place in special chambers on their oral surfaces, but sometimes the ovary or coelom is used. Source: Internet
In a very small number of species, the eggs are retained in the coelom where they develop viviparously, later emerging through ruptures in the body wall. Source: Internet
Excretory organs In almost every segment is a pair of excretory organs called nephridia, which are derived from coelom tissue. Source: Internet