_Midas ursulus_, Geoffr., Ann. Mus., xix., p. 121 (1812); Gray, Cat.
Monkeys Brit. Mus., p. 68 (1870).
_Midas tamarin_, Slack, Proc. Acad. Nat. Sc. Philad., 1861, p. 464.
_Hapale ursula_, Schl., Mus. Pays Bas, vii., p. 265 (1876).
CHARACTERS.--Body long, slender, covered with soft thick fur; ears large,
naked; the face haired. General colour black; nose and lips black; hinder
part of the body rather mottled or banded with reddish-brown or
greyish-white; the hands sometimes black and sometimes yellow. Length, 9
inches; tail, 15 inches.
DISTRIBUTION.--Found on the Lower Amazon, near Para. Mr. Bates says it is
not met with in the Upper Amazon Region, but in its stead a closely allied
species (_Midas nigricollis_), presents itself.[9]
{149}HABITS.--"The _Midas ursulus_ is never seen," writes Mr. Bates, "in
large flocks; three or four is the greatest number observed together. It
seems to be less afraid of the neighbourhood of Man than any other Monkey.
I sometimes saw it in the woods which border the suburban streets, and once
I espied two individuals in a thicket behind the English Consul's house at
Nazareth. Its mode of progression along the main boughs of the lofty trees
is like that of the Squirrels; it does not ascend to the slender branches,
or take wonderful flying leaps like those Monkeys whose prehensile tails
and flexible hands fit them for such headlong travelling. It confines
itself to the larger boughs and trunks of trees, its long nails being of
great assistance to the creature, enabling it to cling securely to the
bark; and it is often seen passing rapidly round the perpendicular
cylindrical trunks. It is a quick, restless, timid little creature, and has
a great share of curiosity, for when a person passes by under the trees
along which a flock is running, they always stop for a few moments to have
a stare at the intruder." In Para, the Negro Tamarin "is often seen in a
tame state in the houses of the inhabitants.... When first taken, or when
kept tied up, it is very timid and irritable. It will not allow itself to
be approached, but keeps retreating backwards when anyone attempts to coax
it. It is always in a querulous humour, uttering a twittering, complaining
noise; its dark, watchful eyes, expressive of distrust, are observant of
every movement which takes place near it. When treated kindly, however, as
it generally is in the houses of the natives, it becomes very tame and
familiar.... It is generally fed on sweet fruits, such as the banana; but
it is also fond of insects, especially soft-bodied spiders and
grasshoppers, which it will snap up with eagerness when within {150}reach.
The expression of countenance in these small Monkeys is intelligent and
pleasing. This is partly owing to the open facial angle, which is given as
one of 60°, but the quick movements of the head, and the way they have of
inclining it on one side, when their curiosity is excited, contribute very
much to give them a knowing expression.... In mobility of expression of
countenance, intelligence and general manners, these small Monkeys resemble
the higher Apes far more than they do any rodent animal with which I am
acquainted, notwithstanding their apparently low organisation in many
points."
This description of the habits of the Negro Tamarin may be taken as
representative of those of the various species of the genus, of whom only
glimpses can be caught in their homes, which are the safe altitudes of the
giants of the virgin forests of Brazil.
THE CAPUCHINS, HOWLERS, AND SPIDER-MONKEYS, &c. FAMILY CEBIDÆ.
This family embraces the typical Platyrrhine Monkeys, and to it belongs the
great majority of the American species. As already pointed out (p. 127)
their nose is flat, and the partition between the nostrils, which open
sideways, is very broad, and separates them widely. They are essentially
quadrupedal, and walk with the soles of both pairs of limbs flat to the
ground. The Spider-Monkeys occasionally, however, assume an erect posture.
"They all possess tails, and in some genera (_e.g._, _Ateles_) this organ
becomes very flexible and muscular, and the under surface of its curled
extremity is devoid of hair and highly sensitive. The tail thus modified is
a powerful prehensile organ and serves for a fifth hand." (_Huxley._) In
these {151}Monkeys there are no cheek-pouches, nor ischial callosities.
Except in the Spider-Monkeys the hind-limbs are longer than the fore-;
"while the thumb, even where it is best developed, is capable of but a
partial opposition to the other fingers, bending almost in the same plane
with the latter, so as to be more like a fifth finger." (_Mivart._)
Nevertheless, all its muscles, except the long flexor, are present. The
great-toe is large and can be moved from and to the side of the other
digits, but is not opposable to them.
The skull is smooth and has no muscular crests; the external bony tube to
the ear is not ossified. The two extremes in its form are presented by the
Howling Monkeys (_Alouatta_) and the Squirrel-Monkeys (_Chrysothrix_), as
pointed out by Professor Huxley in his "Anatomy of Vertebrated Animals":
"In the former the face is very large and prominent, with a low facial
angle. The roof of the brain-case is depressed; the plane of the _occipital
foramen_ [for the passage of the spinal cord] is almost perpendicular" to
the axis of the base of the skull. "In _Chrysothrix_, on the contrary, the
face is relatively small, with a high facial angle; the brain-case is
moderately arched;" and the plane of the _occipital foramen_ is horizontal.
The dentition of the _Cebidæ_ is very characteristic of the family. The
dental formula is I2/2, C1/1, P3/3, M3/3 and the teeth thirty-six in all--a
larger number than is found in any of the Old World forms, or in the
species of the last family (the _Hapalidæ_); for they possess an extra
pre-molar tooth above and below on each side. Their molar teeth are
four-cusped; and in the upper molars of the Spider-Monkeys (_Ateles_) and
of the Howlers (_Alouatta_) there is an oblique cusp, such as is found in
the molars of the _Lemuroidea_, joining the hind inner to the front outer
cusp. Among the _Cebidæ_ the brain varies {152}very much; the posterior
lobes of the main brain (or cerebral hemispheres, which are almost always
convoluted) are also almost always so large as to entirely cover over the
cerebellum (or hind brain), a relation which does not exist between these
two regions of the brain in the _Lemuroidea_. The cerebellum, however, in
the Howlers is slightly uncovered. The absolute size of the brain never, in
any Ape, approaches that of Man. None of the _Cebidæ_ attain the size of
even the medium-sized Old World Apes.
The _Cebidæ_ are all arboreal, and strictly confined to the forest regions
of Tropical America, from the southern part of Mexico to about the parallel
of 30° S. lat. They are divided into four sub-families, namely: The
Douroucolis, or Night-Monkeys (_Nyctipithecinæ_); the Saki Monkeys
(_Pitheciinæ_); the Howlers (_Mycetinæ_); and the Capuchin Monkeys
(_Cebinæ_).