Distribution.—Unknown.
THE WOOLLY MONKEYS. GENUS LAGOTHRIX.
Lagothrix, Geoffr., Ann. Mus., xix., p. 106 (1812).
The animals grouped under the genus Lagothrix are readily distinguished by having a heavy body, and a rounded head, with the muzzle much flattened, and the nostrils nearly circular, but not approximated. More conspicuous than any other external character is the woolliness of their under-fur.
The name Lagothrix was given by Humboldt to the first specimen he found, because of the similarity of its fur to that of the hare, and hence this name, from λαγώς, a hare, and θρίξ, τρῐχὸς, hair, was adopted for the new genus, which was afterwards established by Geoffroy St. Hilaire.
The hair of the crown is short and directed backwards; the tail is long and perfectly prehensile, being naked and sensitive for a considerable distance back from the tip. The limbs are moderately long, and the thumb and great-toe are well developed, the nails of the digits being compressed and pointed.
In regard to the skeleton, the skull of Lagothrix, as Dr. Slack points out, can be readily distinguished from that of the Capuchins by a broad, well-marked, articulation taking place between the pre-maxillary and the nasal bones at right angles to the suture between the latter, while in the Capuchins no true articulation takes place between these bones. The lower jaw is larger than in Cebus, approaching the size and form of Mycetes. The incisor teeth are small and unequal, the upper inner incisor being the largest; the canines are very large and grooved in front.
The Woolly Monkeys are slow in motion, gregarious, diurnal, and arboreal. The "Barrigudos," as they are called by the Portuguese colonists, live exclusively on fruits, and are larger and less active than the Capuchins. They are confined to the forests of the Ecuador district of the Upper Amazon Valley, and along the slopes of the Andes, north to Venezuela and south to Bolivia.
They are of a mild disposition, and, as Mr. Wallace remarks, they are the species "most frequently seen in confinement, and are great favourites, from their grave countenances, which resemble the human face more than those of any other Monkeys, their quiet manners, and the great affection and docility they exhibit."
I. HUMBOLDT'S WOOLLY MONKEY. LAGOTHRIX LAGOTHRIX.