{167}The frontal lobes of the brain are broad and much flattened, and not full and rounded as in the Orang. The olfactory bulbs project forward, slightly beyond the frontal lobes of the cerebrum; the occipital lobes are much reduced, while the large cerebellum projects distinctly backwards from below the cerebrum--characters in which this very highly organised member of the genus shows a retrogressive development, thus differing from all the other Man-like Apes, in all of which the cerebrum entirely covers both the olfactory lobes in front, and the cerebellum behind. The large laryngeal sac, communicating by two openings with the larynx, and formed by the extension of the thyro-hyoid membrane, distinguishes this from all the other Gibbons. DISTRIBUTION.--The Siamang is confined to the island of Sumatra. It has been recorded from Malacca and Tenasserim; but some doubt exists as to the accurate determination of the individuals referred to, no really authentic specimen having yet been obtained out of Sumatra. HABITS.--The Siamang is gregarious, frequenting the great forest-trees from 200 to 300 feet above the sea up to 3,000 or 4,000 feet. I made the acquaintance of this species in Southern Sumatra, and during my stay in that island had various opportunities of observing many of them in their homes. It was not uncommon to come suddenly on a colony of them both in the forest and among the tall isolated outliers, when they happened to be covered with fruit. The satiated members of the company {168}might then be often seen hanging by one arm from a bare branch, with perhaps eighty unobstructed feet between them and the ground, making the woods resound with their loud barking howls, uttered apparently for pure love of making a noise. On one occasion a young one, found clinging to its mother, which had been shot, was brought in alive. It had been only stunned by a pellet on the head, and had no bones broken. In a very short time it became a most delightful companion. The following observations in reference to it are taken from the writer's Journal: "Its expression of countenance is most intelligent and often very human; but in captivity it generally wears a sad and dejected aspect, which quite disappears in its excited moods. With what elegance and gentleness it takes with its delicate taper fingers whatever is offered to it! Except for their hairiness, its hands, and, in its youth at all events, its head, seem to me more human than those of any other Ape's. It rarely, however, brings its thumb into opposition with the other fingers, but usually clasps the whole hand, without that digit, on an object. It will never put its lips to a vessel to drink, but invariably lifts the water to its mouth, by dipping in its half-closed hand and then awkwardly licking the drops from its knuckles. It generally sits with its arms crossed over its chest, and its fingers overlaid behind its head. The