On the other hand, some of the larger baboons were greatly terrified, and grinned as if on the point of screaming out. When I showed a little dressed-up doll to the _Cynopithecus niger_, it stood motionless, stared intently with widely opened eyes, and advanced its ears a little forwards. But when the turtle was placed in its compartment, this monkey also moved its lips in an odd, rapid, jabbering manner, which the keeper declared was meant to conciliate or please the turtle.
 Boston Journal of Nat. Hist. 1845---47, vol. v. p. 423. On the Chimpanzee, ibid. 1843-44, vol. iv. p. 365.
 See on this subject, `Descent of Man,' vol. i. p. 20.
I was never able clearly to perceive that the eyebrows of astonished monkeys were kept permanently raised, though they were frequently moved up and down. Attention, which precedes astonishment, is expressed by man by a slight raising of the eyebrows; and Dr. Duchenne informs me that when he gave to the monkey formerly mentioned some quite new article of food, it elevated its eyebrows a little, thus assuming an appearance of close attention. It then took the food in its fingers, and, with lowered or rectilinear eyebrows, scratched, smelt, and examined it,-- an expression of reflection being thus exhibited. Sometimes it would throw back its head a little, and again with suddenly raised eyebrows re-examine and finally taste the food.
In no case did any monkey keep its mouth open when it was astonished. Mr. Sutton observed for me a young orang and chimpanzee during a considerable length of time; and however much they were astonished, or whilst listening intently to some strange sound, they did not keep their mouths open. This fact is surprising, as with mankind hardly any expression is more general than a widely open mouth under the sense of astonishment. As far as I have been able to observe, monkeys breathe more freely through their nostrils than men do; and this may account for their not opening their mouths when they are astonished; for, as we shall see in a future chapter, man apparently acts in this manner when startled, at first for the sake of quickly drawing a full inspiration, and afterwards for the sake of breathing as quietly as possible.
 `Descent of Man,' vol, i. p, 43.
Terror is expressed by many kinds of monkeys by the utterance of shrill screams; the lips being drawn back, so that the teeth are exposed. The hair becomes erect, especially when some anger is likewise felt. Mr. Sutton has distinctly seen the face of the _Macacus rhesus_ grow pale from fear. Monkeys also tremble from fear; and sometimes they void their excretions. I have seen one which, when caught, almost fainted from an excess of terror.
Sufficient facts have now been given with respect to the expressions of various animals. It is impossible to agree with Sir C. Bell when he says that "the faces of animals seem chiefly capable of expressing rage and fear;" and again, when he says that all their expressions "may be referred, more or less plainly, to their acts of volition or necessary instincts." He who will look at a dog preparing to attack another dog or a man, and at the same animal when caressing his master, or will watch the countenance of a monkey when insulted, and when fondled by his keeper, will be forced to admit that the movements of their features and their gestures are almost as expressive as those of man. Although no explanation can be given of some of the expressions in the lower animals, the greater number are explicable in accordance with the three principles given at the commencement of the first chapter.
 `Anatomy of Expression,' 3rd edit. 1844, pp. 138, 121. CHAPTER VI.
SPECIAL EXPRESSIONS OF MAN: SUFFERING AND WEEPING.
The screaming and weeping Of infants--Forms of features-- Age at which weeping commences--The effects of habitual restraint on weeping--Sobbing--Cause of the contraction of the muscles round the eyes during screaming--Cause of the secretion of tears.