3162. Digestive system. 32 Color Photomicrographs. 1. Amoeba proteus, digesting within food vacuoles 2. Paramaecium, food vacuoles stained 3. Hydra, l.s. hypostome and gastrovascular cavity 4. Hydra, l.s. with food 5. Intestinal wall of earthworm 6. Intes