This sub-order comprises the Lemurs proper (Tarsius, Lemur, and other genera) and the Aye-Ayes (Chiromys).
Anthropoidea. The Anthropoidea are the most highly organized Primates. They are chiefly modified for an arboreal life. The body is hairy instead of furry, but only slightly so in man. The incisors do not exceed 2/2; the molars are 3/3, except in the marmosets, where they are 2/2. The upper, median incisors are in close contact. The orbital and temporal fossæ are separated by a broad vertical plate. The lachrymal foramen is situated inside the orbital fossa. All of the digits are provided with flat nails, except in the Hapalidæ, in which all except the big toe (hallux) are provided with a claw. In some the thumb (pollex) is rudimentary or absent. The clavicle is well developed. The cerebrum is usually richly convoluted, and more or less completely covers the cerebellum. The uterus has no horns. The placenta is deciduate and metadiscoidal.
The Anthropoidea are subdivided into the two following groups:
- Super-family 1.—Platyrrhinæ (New-World Monkeys).
- Super-family 2.—Catarrhinæ (Old-World Monkeys).
The Platyrrhinæ or New-World Monkeys are subdivided into the following families, viz.:
- Family 1.—Hapalidæ.
- Family 2.—Cebidæ.
The Catarrhinæ or Old-World Monkeys are subdivided into the following families, viz.:
- Family 1.—Cercopithecidæ.
- Family 2.—Simiidæ.
- Family 3.—Hominidæ.