A spongocoel (/ˈspɒŋɡoʊˌsiːl/) is the 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.
The spongocoel is lined by a variety of cell types, each lending a unique function:
Porococytes--These cells line the pores of the sponge. They are the structure through which water is taken into the organism.
Choanocytes--These cells exhibit flagella that create inward currents of water for the sponge's stationary filter feeding mechanism.
Amoebocytes--These are motile cells that perform various digestive functions within the sponge by transporting/storing food and excreting waste.