It means having two germ layers - ectoderm and endoderm.
Porifera is diploblastic.
The sponge is another name for poriferans.
Porifera consists primarily of marine creatures with a few freshwater species tossed in for good measure. Their bodies are asymmetrical.
Cylindrical, vase-like, spherical, or sac-like body forms are all possibilities. Because they have two layers, one on the exterior and one on the inside, they are diploblastic.
The poriferans are characterized by an unusual feeding technique in which water is drawn through minute holes or pores in their exterior walls.
Cells in the sponge walls filter out the good material as water circulates through the body and out of the other larger openings.
Sponge cells appear to be more self-contained than other animal cells and perform a wide range of biological processes.