composed of bone-substance of about the size of a goose-egg, which is set in the hollow of the under jaw. It looks from without like a wen, and acts as a sounding-board to strengthen the voice to an almost incredible extent. The females have a similar apparatus, but only about an inch in size. I do not know what it is that prompts the animal to set up its great cry. It is believed in the colony that it cries out only when the flood-tide begins, but this is wrong, for these apes howl at all times of day, and quite as much in the interior of the country, where there can be no tide. There may be some atmospheric influence which provokes the males to howl, while the females join in with them. There can not be a sexual impulse in the matter, for that would not make old and young howl together. I have had opportunities to hear this howling a great many times, and to observe the howlers from a very close vicinity. Every time, there sat an old male up in a tree, supporting himself on his fore-feet, and having his long tail, naked of hair on the inside for about nine inches from the end, black and smooth as a hand, wrapped around a limb, while other males, females, and young sat beneath him in a variety of positions. All at once the old fellow would set up a horrible rattling "Rochu, rochu!" which, after five or six repetitions, passed into a bellowing in which all the others would join, and which was loud enough to make one afraid of losing his hearing. It is so loud that it can be heard on still nights two leagues off; and it lasts for about ten minutes, and then subsides. The roar of the tigers, which troubled Pichegru and his companions so much on their flight from Cayenne to Surinam, was evidently nothing else than the howling of these apes, which might well fill one, hearing it for the first time, and not knowing that it came from harmless monkeys, with fright. The howling ape is sluggish and melancholy, and jumps only when it is pursued, while at other times it climbs deliberately among the trees, always holding itself by the tail. When captured young it becomes tame and confiding, and will play with cats and dogs, but is usually quiet, and if the person to whom it is attached goes away, it indulges in a continual rattling and highly unpleasant cry.
I could never succeed in raising one of them. They have a peculiarly unpleasant odor, by which one can easily tell when he is near one. Like all the apes, they bring only one young into the world at a time. Their principal enemy is the tufted eagle (Falco destructor).
The quatta (Ateles panisciis) is as large as the howling ape, but slimmer and not so slow. It does not appear on the coast, but only in the higher lands, where it constitutes a choice game for the bush negroes. Its head, body, tail, and feet are clothed in bright black hairs, while its nearly bare, narrow, ruddy face is very like that of an old Indian woman. The tail, about three feet long, is, like the tail of the alouatte, bare on the under side for about nine inches. The tip of the tail is also the animal's most delicate organ of feeling, and commonly
