Barrel Sponge (Xestospongia testudinaria)
The barrel sponge is a demosponge (the most common sponge class that is made up of 95% of all sponges) found in the waters of Southeast Asia (which includes countries like Thailand, the Philippines, Indonesia, Malaysia, and Laos). The barrel sponge's size is big enough to fit a person inside (up to 6 feet tall). Like other sponges, the barrel sponges have no specific organ systems, but rather specialized cells called collar cells. These cells are used to draw water into the sponge's body, where food is filtered from the water and released through the osculae (the large openings around the sponge's body, particularly the top in this case).