Chap. V. MONKEYS. Ul 



knuckles; this was difficult as the flies buzzed about, 

 and at each attempt the lips were firmly compressed, and 

 at the same time slightly protruded. 



Although the countenances, and more especially the 

 gestures, of orangs and chimpanzees are in some re- 

 spects highly expressive, I doubt whether on the whole 

 they are so expressive as those of some other kinds of 

 monkeys. This may be attributed in part to their ears 

 being immovable, and in part to the nakedness of their 

 eyebrows, of which the movements are thus rendered less 

 conspicuous. When, however, they raise their eyebrows 

 their foreheads become, as with us, transversely wrinkled. 

 In comparison with man, their faces are inexpressive, 

 chieflv owing to their not frowning under anv emotion 

 of the mind — that is, as far as I have been able to ob- 

 serve, and I carefully attended to this point. Frown- 

 ing, which is one of the niost'important of all the expres- 

 sions in man, is due to the contraction of the corrugators 

 by which the eyebrows are lowered and brought together, 

 so that vertical furrows are formed on the forehead. 

 Both the orang and chimpanzee are said 18 to possess 

 this muscle, but it seems rarely brought into action, at 

 least in a conspicuous manner. I made my hands into 

 a sort of cage, and placing some tempting fruit within, 

 allowed both a young orang and chimpanzee to try their 

 utmost to get it out; but although they grew rather 

 cross, thev showed not a trace of a frown. Xor was there 

 any frown when they were enraged. Twice I took two 

 chimpanzees from their rather dark room suddenly into 

 bright sunshine, which would certainly have caused us 

 to frown; they blinked and winked their eyes, but only 



18 Prof. Owen on the Orang 1 , Proc. Zool. Soc. 1830, p. 

 28. On the Chimpanzee, see Prof. Macalister, in Annals 

 and Mag-, of Xat. Hist. vol. vii. 1871, p. 342, who states 

 that the corrugator supercilii is inseparable from the 

 orbicularis palpebrarum. 



