Poriferans don't have mouths; instead, they draw water through tiny holes in there outer shell. Cells in the sponge walls filter food from the water as the water is pumped through the body and out other larger openings. The beating flagella inside the sponge makes the flow of the water random, pushing it through canal like paths. Sponge cells perform a variety of bodily functions and appear to be more independent of each other than are the cells of other animals. There are approximately 5,000-10,000 species of prorifera.