Usually containing openings for food intake and ejection of waste, protostomes and deuterostomes are the two divisions that contain it.  
Although its origins are unknown, some scientists theorize that it may have formed from gastric pouches of Cnidarian ancestors.  In annelids and mollusks, it is usually formed from splitting and hollowing of the mesodermal mass in embryonic development, while in humans, it develops between the somatic and splanchnic layers and can be divided into pericardial and peritoneal portions.  Usually containing openings for food intake and ejection of waste, protostomes and deuterostomes are the two divisions that contain it.  FTP, name this central body cavity only present in higher animal phyla.
Although its origins are unknown, some scientists theorize that it may have formed from gastric pouches of Cnidarian ancestors.  
coelom