Inner, water-filled cavity of members of phylum Porifera.
The spongocoel is not a body cavity but instead exists outside external to the tissue making up a sponge's body. This is just as or gastrovascular cavities too exist external to the tissues of other animals.
In sponges water flows into the spongocoel from in the sponge's body. Water then exits the spongocoel through the osculum, minus whatever particles that have been removed by these suspension-feeding animals.