This slide shows several stained specimens of Amoeba proteus (Proteus  was a Greek god that could assume various forms).  These relatively large protozoans use mobile extensions of the cytoplasm called pseudopodia for movement and food capture.  Ingested food is surrounded by a food vacuole and digested by enzymes. Clear areas called contractile vacuoles collect excess water from the surrounding cytoplasm and discharge it to the outside of the body.  Also note the darkly stained nuclei, which contain granular chromatin and control the activities of these unicellular organisms.