A spongocoel (), also called paragaster (or paragastric cavity), is the large, central cavity of

sponge Sponges or sea sponges are primarily marine invertebrates of the animal phylum Porifera (; meaning 'pore bearer'), a basal clade and a sister taxon of the diploblasts. They are sessile filter feeders that are bound to the seabed, and a ...

s. 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

choanocyte Choanocytes (also known as "collar cells") are cells that line the interior of asconoid, syconoid and leuconoid body types of sponges that contain a central flagellum, or ''cilium,'' surrounded by a collar of microvilli which are connected by ...

s, which have

flagella A flagellum (; : flagella) (Latin for 'whip' or 'scourge') is a hair-like appendage that protrudes from certain plant and animal sperm cells, from fungal spores ( zoospores), and from a wide range of microorganisms to provide motility. Many pr ...

that push water through the spongocoel, creating a current. The spongocoel is lined by a variety of cell types, each having a unique function: * porocytes – line the pores of the sponge and are the structure through which water is taken into the organism * choanocytes – exhibit flagella that create inward currents of water for the sponge's stationary filter feeding mechanism * amoebocytes – motile cells that perform various digestive functions within the sponge by transporting and/or storing food and excreting waste.

References

Sponge anatomy {{Animal-anatomy-stub