With an animals without fins, the viscous sponge does a very good job of collecting food. The sponge collects food by ventilating water through its pores. Food particles and bacteria get trapped in the pores in the sponge as it passes through. These pores filter the particles and go through the three layers of the sponges outside. There is the inner, middle, and outer layers and all of them do something different things. the outer layer just consists of flat epidermis cells. The medium layer consists of a gelatinous substance and ameoboid cells that migrate within the layer. The inner layer consists of flagellated cells and collar cells as well as choanocytes. As it is obvious, the sponge has no actual digestive system with organs and acids and enzymes. instead, they digest the nutrients in food and these nutrients are stored in food vacuoles which transfer them to the ameoboid and to cells in the middle wall. A photo of all of the different layers of the sponge is shown to the right.