186 
NATURAL HISTORY. 
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.* 
Buffon was a great admirer of this long-tailed, very human-headed little Monkey, and remarked 
that they wil] 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 as 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-fiftli 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 liuman-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.t 
Le Vaillant, in his introduction to his first voyage, gives the following curious instance of the exhi- 
bition of their instinct of clinging to their mother under extraordinary circumstances : — When living in 
* CalUtihrix sciurca. 
t It appears* to be a long-backed little thing, and this is not because it has more rib-bearing back-bones than the 
Monkeys of the Old World; on the contrary, they usually number only eleven. As regards the skeleton, the hips appear to 
be weakly joined on to the spine and to each other by one bone, instead of there being a long and strong sacrum to unite 
them. The breast-bone has only four pieces between the upper one (or the manubrium), and the cartilage at the lower end. 
