The Gibbons, or long-armed apes, forming the genus Hylobates, (7 species) are found in all the large islands of the Indo-Malayan sub-region, except the Philippines; and also in Sylhet and Assam south of the Brahmaputra river, eastward to Cambodja and South China to the west of Canton, and in the island of Hainan.

The Siamang (Siamanga syndactyla) presents some anatomical peculiarities, and has the second and third toes united to the last joint, but in general form and structure it does not differ from Hylobates. It is the largest of the long-armed apes, and inhabits Sumatra and the Malay peninsula.

Family 2.—SEMNOPITHECIDÆ. (2 Genera, 30 Species.)

General Distribution.
Neotropical
Sub-regions.		Nearctic
Sub-regions.		Palæarctic
Sub-regions.		Ethiopian
Sub-regions.		Oriental
Sub-regions.		Australian
Sub-regions.
— — — —— — — —— — — 41. 2 — —1. 2. 3. 4— — — —

The Semnopithecidæ, are long-tailed monkeys without cheek-pouches, and with rather rounded faces, the muzzle not being prominent. They have nearly the same distribution as the last family, but are more widely dispersed in both Africa and Asia, one species just entering the Palæarctic region.

The Eastern genus Presbytes or Semnopithecus (29 species), is spread over almost the whole of the Oriental region wherever the forests are extensive. They extend along the Himalayas to beyond Simla, where a species has been observed at an altitude of 11,000 feet, playing among fir-trees laden with snow wreaths. On the west side of India they are not found to the north of 14° N. latitude. On the east they extend into Arakan, and to Borneo and Java, but not apparently into Siam or Cambodja. Along the eastern extension of the Himalayas they again occur in East Thibet; a remarkable species with a large upturned nose (S. roxellana) having been discovered by Père David at Moupin (about Lat. 32° N.) in the highest forests, where the winters are severe and last for several months, and where the vegetation, and the other forms of animal life, are wholly those of the Palæarctic region. It is very curious that this species should somewhat resemble the young state of the proboscis monkey (S. nasalis), which inhabits one of the most uniform, damp, and hot climates on the globe—the river-swamps of Borneo.

Colobus, the African genus (11 species), is very closely allied to the preceding, differing chiefly in the thumb being absent or rudimentary. They are confined to the tropical regions—Abyssinia on the east, and from the Gambia to Angola and the island of Fernando Po, on the west.

Family 3.—CYNOPITHECIDÆ. (7 Genera, 67 Species).

General Distribution.
Neotropical
Sub-regions.		Nearctic
Sub-regions.		Palæarctic
Sub-regions.		Ethiopian
Sub-regions.		Oriental
Sub-regions.		Australian
Sub-regions.
— — — —— — — —— 2 — 41. 2. 3 —1. 2. 3. 41 — — —

This family comprehends all the monkeys with cheek pouches, and the baboons. Some of these have very long tails, some none; some are dog-faced, others tolerably round-faced; but there are so many transitions from one to the other, and such a general agreement in structure, that they are now considered to form a very natural family. Their range is more extensive than any other family of Quadrumana, since they not only occur in every part of the Ethiopian and Oriental regions, but enter the Palæarctic region in the east and west, and the Australian region as far as the islands of Timor and Batchian. The African genera are Myiopithecus, Cercopithecus, Cercocebus, Theropithecus, and Cynocephalus; the Oriental genera, Macacus, and Cynopithecus.