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]]
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 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 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.