_Brachyteles_, Spix, Sim. et Vespert. Brazil, p. 36 (1823).
_Eriodes_, Is. Geoffr., Dict. Class., xv., p. 143 (1829).
The members of this genus resemble in general form the {225}Spider-Monkeys,
to be presently described, and they present also many resemblances to the
foregoing species of the Woolly Monkeys. Their limbs are long and slender,
and their body heavy, and covered with a woolly under-fur. Their head is
rounder than in the Capuchins. The face is flat, and the facial angle
large. The nose has the partition between the nostrils narrower than in the
other species of the family, and the nostrils are themselves more
approximated, circular in form, and directed more downward than outward,
thus showing some approach to the position of the nostrils in the Old World
Apes. Their fore-limbs are long and slender, and the thumb is often
entirely absent (as in the Guerezas of Africa), or there may be a very
rudimentary digit, which sometimes ends in a small nail. The nails of the
digits are, as in _Lagothrix_, very compressed and sharp. The tail is
longer than the body, naked on the under side, and sensitive at its
termination, and therefore prehensile.
The skull is globular, and the pre-maxillary bones articulate with the
nasal bones by a broad surface. The incisor teeth are equal in size; the
canines are small, and of the same length as the incisors, and the molars,
which are vertically higher than the canines, are thick and quadrangular.
The lower jaw is dilated behind, somewhat less than in _Lagothrix_.
The Woolly Spider-Monkeys are very rare, and little is known of their
habits. They are confined to the south-eastern coast forests of Brazil,
that region to the south of Cape San Roque, whence, as far as Rio Grande do
Sul, ever-verdant forests, as Mr. Wallace has described, clothe all the
valleys and hills of the lowland region, stretching as far west as the
higher mountain ranges parallel to the coast, and even up the valleys of
the larger rivers a long way into the interior of the country.
{226}THE BROWN WOOLLY SPIDER-MONKEY. BRACHYTELES ARACHNOIDES.
_Ateles arachnoides_, Geoffr., Ann. Mus., vii., p. 271 (1806); xiii., p.
90, pl. 9 (1809); xix., p. 106 (1812); Schl., Mus. Pays Bas, vii., p. 184
(1876, part.).
_Ateles hypoxanthus_, Desm., Mamm., p. 75 (1820); Neuwied, apud Kuhl,
Beitr. Zool., p. 25 (1820); Schl., t. c. p. 185 (1876, part.).
_Brachyteles macrotarsus_, Spix, Sim. et Vespert., Bras., p. 36, pl. 17
(1823).
_Eriodes hemidactylus_ and _E. tuberifer_, Geoffr., Mém. Mus., xvii., pp.
161, 163 (1828).
_Eriodes arachnoides_, Geoffr., Mém. Mus., t. c. p. 160 (1828).
_Brachyteles arachnoides_, Gray, Cat. Monkeys Brit. Mus., p. 45 (1870).
CHARACTERS.--MALE.--Size small; face nude, flesh-coloured; general colour
of body yellowish-brown, darker on the back of the head, with a few long
black hairs on the forehead; hairs of head short and directed backward;
buttocks, vent, base of tail and perineal region dark ferruginous-brown;
the thumb wanting or rudimentary. Length of body, 22 inches; tail, 26
inches.
FEMALE.--Ashy-brown, instead of yellowish-brown, in appearance.
YOUNG.--In some young specimens the general colour is dark brown, with the
sides of the face white.
Dr. Slack observes, in the "Proceedings of the Academy of Natural Sciences
of Philadelphia" for 1862, in reference to this species: "I had long
suspected that the three species of this genus described by Isidore
Geoffroy St. Hilaire, were in reality one and the same; no specific
characters are manifest in their coloration, or skulls, the supposed
differences being {227}based upon the development of the anterior thumbs,
this member being absent in _B. arachnoides_, replaced by a small nailless
tubercle in _B. tuberifer_, and surmounted by a nail in _B. hemidactylus_.
In the "Magazin" of Messrs. Verreaux, in Paris, I found specimens having
upon one hand the tubercle, and upon the other the nailed thumb, others
with the tubercle on one hand, but absent upon the other. St. Hilaire
himself, in his "Catalogue of the Primates," expresses a doubt as to
whether _B. arachnoides_ and _B. hemidactylus_ are really distinct. In
September and October, 1860, I was unable to find _B. hemidactylus_ in the
Paris Museum, all the _Brachyteles_ being labelled _Eriodes arachnoides_."
DISTRIBUTION.--Confined to the wooded region of the south-east of Brazil.
HABITS.--Arboreal, diurnal, and (it is supposed) gregarious, frequenting
the high forest trees, and subsisting on fruits.