In the first division are the Squirrel Monkeys, the Sakis, and the Douroucoulis, forming respectively the genera Callithrix, Pithecia, and Nyctipithecus; and in the second there are the Marmosets and Tamarins, of the genera Hapale and Midas. The second division is distinctly separated from the other by some comparative anatomists, and forms the group of “Arctopitheci,” or Bear Monkeys.
GENUS CALLITHRIX[92]—THE SAIMARIS.
Callithrix means lovely hair, from κάλλος and θρίξ, and merely refers to the pretty fur of these Monkeys, and gives no insight into their peculiarities, and is a mere name. It includes the Squirrel Monkeys, which are distinguished by having good-sized canine teeth, and by the first crushing tooth being conical in shape, and having an extra tubercle on its base; on the other hand, there are other kinds in it which have short canine teeth, such as the Widow Monkey.
All have the peculiarities of the non prehensile-tailed group, but their front teeth do not project forwards. The tail is round and slender.
THE SQUIRREL MONKEY.[93]
Buffon was a great admirer of this long-tailed, very human-headed little Monkey, and remarked that they will always be admired more than any other of their American brethren, on account of their littleness, the gentleness of their movements, their brilliant colour, their large and striking eyes, and their little round faces. He noticed that although the tail was long it was not stout and muscular, as is the case in those which are prehensile; and he observed that they were fond of curling it around objects, and even around their own or their mate’s bodies. Their grey olive body-fur contrasts with their bright red arms and legs, whilst the muzzle is blackish, and these colours, on an active little creature whose body is about ten inches long, and whose tail is not quite fourteen, look very pretty.
Humboldt often had the opportunity of watching the Saimaris, and was much impressed with their affectionate disposition, and says that they readily wept if they were spoken to in a sad manner. When they are spoken to for some time they will listen with great attention, and then will place their little hands to the speaker’s lips. The attempt suggests the great trouble to catch the words as they come out of the mouth. They knew objects when they saw them in pictures, and even when they were not coloured, and when they represented their usual food, such as fruit and insects, they endeavoured to catch hold of them. They entertained a great desire to catch Spiders, and caught them with great skill, either with their hands or mouths.
They feel any sudden change in the temperature of their native woods very soon, and when there is a fall of some degrees in the thermometer, they collect in little troops, and huddle together for the sake of their mutual warmth. There is a vast deal of squabbling and fighting to see who shall get in the middle, and not be left out in the cold, and great is the whistling and squeaking. Unfortunately for the noisy creatures, the Indian hunters take advantage of their assembling in this manner, for when they hear the cries they shoot their arrows in the direction of the Monkeys, and often hit the chilly little group. It is said that when young they have a slight smell of musk.
The Squirrel Monkeys have a small face, and the brain-case behind it is moderately arched above, and sticks out behind very decidedly. This is because the head is placed on the spine differently to the Monkeys already described. In them the opening in the under part of the skull, for the passage of the spinal cord (the foramen magnum) is far back, but in the Squirrel Monkeys it is much further forward; so far forward, indeed, that there is enough room for brain matter behind it to allow the back part of the brain to be relatively larger than in man. Huxley remarks that in this Monkey the cerebral hemispheres (that is to say, the whole of the “brain proper”) project beyond the cerebellum to a greater relative extent than in any other Mammal nearly by one-fifth of their total length. But the fore part of the brain is small, and there are very few convolutions. On referring to the description of the Howlers, this great difference will be appreciated. Gervais, with a laudable desire to account for the great development of the back part of the head, insists on the great love the young show their mother, not leaving her even when she is dead. The orbits of this Monkey are large, and are close together; they are not perfectly separated by bone, for a membrane shuts one off from the other; and the cheek-bone has not the round hole in it which is observed in the Spiders and Howlers. As a whole, the head is very human-like, especially when it is young; but the forehead-bone is triangular, and projects upwards and backwards between the side bones of the head, and the chin is round and prominent. The forehead is narrow, and the muzzle is more protruding, however, than in man.[94]
Le Vaillant, in his introduction to his first voyage, gives the following curious instance of the exhibition of their instinct of clinging to their mother under extraordinary circumstances:—When living in Dutch Guiana, at Paramaribo, where he was born, and where he had already, though very young, formed a collection of insects, the future traveller and his party in one of their excursions had killed a female Monkey. “As she carried on her back a young one, which had not been wounded, we took them both along with us, and when we returned to the plantation, my Ape had not quitted the shoulders of its mother. It clung so closely to them, that I was obliged to have the assistance of a negro to disengage them; but scarcely was it separated from her, when, like a bird, it darted upon a wooden block that stood near, covered with my father’s peruke, which it embraced with its four paws, nor could it be compelled to quit its position. Deceived by its instinct, it still imagined itself to be on the back of its mother, and under her protection. It seemed perfectly at ease on the peruke. I resolved to suffer it to remain, and to feed it there with Goat’s milk. It continued in its error for three weeks, but after that period, emancipating itself from its own authority, it quitted the fostering peruke, and by its amusing tricks became the friend and favourite of the whole family;” though it is difficult to suppress a smile at the idea of a Monkey clinging to a full-bottom on a wig-block, and fancying it its mamma. The story, as it begins mournfully with the slaughter of the poor mother, ends tragically for her unhappy offspring. It died a terrible death—the result, indeed, of its own mischievous voracity, but in agonies frightful to think of. “I had, however,” continues Le Vaillant, “without suspecting it, introduced the wolf among my flock. One morning, on entering my chamber, the door of which I had been so imprudent as to leave open, I beheld my unworthy pupil making a hearty breakfast on my noble collection. In the first transports of my passion I resolved to strangle it in my arms; but rage and fury soon gave place to pity, when I perceived that its voraciousness had exposed it to the most cruel punishment. On eating the Beetles it had swallowed some of the pins on which they were fixed, and though it made a thousand efforts to throw them up, all its exertions were in vain. The torture which it suffered soon made me forget the devastation it had occasioned. I only thought of affording it relief; but neither my tears, nor all the art of my father’s slaves, whom I had called from all quarters with loud cries, were able to preserve its life.”