spongeocoel 2011-04-22T07:05:15Z ATRIUM: "Preoscular cavity. This term is used specifically to designate the central exhalant cavity" [http://www.portol.org/thesaurus] PORO:0000037 atrium cjm cloaca gastal cavity large, central cavity of sponges. Water enters the spongocoel through hundreds of tiny pores (Ostia) and exits through the larger opening (osculum). Depending on the body plan of the sponge (which can be asconoid, syconoid, or leuconoid), the spongocoel could be a simple interior space of the sponge or a complexly branched inner structure. Regardless of body plan or class, the spongocoel is lined with choanocytes, which have flagella that push water through the spongocoel, creating a current. immaterial anatomical entity