MAN'S COUSINS THE APES 45 



bare skin the monkeys stand alone among the Mammalia. 

 The hues displayed are remarkable for their brilliancy, 

 and this varies in intensity, waxing and waning with 

 the varying moods of their possessors, and attain- 

 ing their maximum during periods of sexual excite- 

 ment. Blue, green, red, and violet are the dominant 

 colours, and these are confined to the face, buttocks, 

 and genital organs. The same hues are commonly present 

 in both sexes, though in the female they are less 

 brilliant. Normally the male appears to be unconscious 

 of the conspicuous patches of colour, but when under 

 the irrepressible stimulus of sexual excitement he seems 

 to endeavour to make the utmost possible capital out of 

 such adornments, more especially presenting his buttocks 

 to his mate in an apparent endeavour to stimulate her 

 desire. In some species, as with the Baboons for example, 

 the naked area of this hinder part of the body is a much 

 more conspicuous feature in the female than in the male, 

 becoming enormously swollen and carunculated, and from 

 its vivid red colour presents a positively revolting appear- 

 ance, according to our standard of what is beautiful. 

 The most vividly coloured species of all is the Mandrill, 

 which, in this matter exceeds all other living Mammals. 

 The face, in the male, is produced forward to give the 

 head a dog-like shape, while the whole of the upper surface 

 of the muzzle has been transformed into a swollen, deeply- 

 fluted mass by the excessive inflation of the underlying 

 bone. The bare skin covering this is of a brilliant cobalt 

 blue, with lines of violet in the furrows, while the nose 

 is of a bright scarlet. The naked skin of the buttocks, 

 and the genital organs, are suffused with brilHant tints of 

 scarlet and blue. In spite of the purity and briUiance of the 

 coloration the effect is to make the creature really hideous. 



