One day I heard three sounds which a native boy assured me were made by gorillas; they were in different directions from the cage. It was not a scream nor a howl, but somewhat resembled the human voice calling out with a sound like “he-oo!” These sounds were repeated at intervals, but did not appear to be in the relation of call and answer; and the animals making them did not approach each other while calling. The sounds were the same except in volume. One of them appeared to be made by an animal much larger than the animals that had made the two other sounds. I should state that this sound rarely occurred within my hearing during my stay in that part, and with one exception I never heard a gorilla make any loud sound during the day. Another interesting specimen came prowling through the jungle as if he had lost his way. He found a small opening, or tunnel, which I had cut through the foliage in order to get a better view. Turning into that, he came a few steps towards the cage before he discovered it. Suddenly he stopped and squatted on the ground. He did not sit flat down. For a few seconds he was motionless. So was I. He slowly raised one arm till his hand was above his head, in which position he sat for a few moments. Then he moved his hand quickly forward, as if to motion at me. He did not drop his hand to the ground, but held it for a short time at an angle from his face. Then he slowly let it down till it reached the ground. During this time he kept his eyes fixed on me. At length he raised the other arm and seized hold of a strong bush, by which he slowly drew himself to a half-standing position. Thus he stood for a few seconds, with one hand resting on the ground. Suddenly he turned to one side, parted the bushes, and disappeared. He uttered no sound whatever. Another came within about thirty yards of my retreat. When he discovered me he stopped and stared in a perplexed manner. He turned away to retreat, but, after going a few feet, turned round and sat down on the ground. He remained in that attitude for more than half a minute; then he rose and retired in the direction from which he had come.