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.