| Present in | Found in the outer layer of the sponge body | Found in the inner layer of the sponge body |
| Cell types | Flattened epithelial cells (pinacocytes) | Collar cells or choanocytes |
| Function | Protective layer, involved in maintaining the shape of the sponge | Choanoderm is involved in water filtration and feeding processes |
| Structure | Single layer of pinacocytes | Inner layer composed of choanocytes |
| Movement of water | Does not participate in water movement | Generates water currents through the movement of flagella on choanocytes |
| Role in feeding mechanism | Not involved in feeding processes | Actively involved in filter-feeding, capturing food particles from water |
| Cellular structure | Cells are flattened and form a protective barrier | Cells have a collar-like structure with a flagellum, creating water currents |
| Function in sponges | Protective and structural role | Essential for the sponge’s feeding and nutrient acquisition |
