Chap. XVIII. ORNAMENTAL COLOURS. 293 



yellow beard. " Toutes les parties superieures de leurs 

 " cuisses et le grand espace nii de leurs fesses sont 

 " egalement colores du rouge le plus vif, avec uii 

 " iiielauge de bleu qui ne manque reellement pas 

 " d'elegauce." ^^ When the animal is excited all the naked 

 parts become much more vividly tinted. Several authors 

 have used the strongest expressions in describing these 

 resplendent colours, which they compare with those of 

 the most brilliant birds. Another most remarkable 

 peculiaiity is that when the great canine teeth are fully 

 developed, immense protuberances of bone are formed 

 on each cheek, which are deeply furrowed longitudinally, 

 and the naked skin over them is brilliantly-coloured, as 

 just described. (Fig. G7.) In the adult females and in 

 the young of both sexes these protuberances are scarcely 

 perceptible ; and the naked parts are much less brightly 

 coloured, the face being almost black, tinged with blue. 

 In the adult female, however, the nose at certain regular 

 intervals of time becomes tinted with red. 



In all the cases hitherto given the male is more 

 strongly or brightly coloured than the female, and dif- 

 fers in a greater degree from the young of both sexes. 

 But as a reversed style of colouring is characteristic of 

 the two sexes with some few birds, so with the Khesus 

 monkey (Macacus rhesus) the female has a large surface 

 of naked skin round the tail, of a brilliant carmine red, 

 which periodically becomes, as I was assured by the 

 keepers in the Zoological Gardens, even more vivid, 

 and her face is also pale red. On the other hand with 



'' Gervais, 'Hist. Nat. des Mammiferes,' 1854, p. 103'. Figures are 

 given of the skull of the male. Desmarest, ' Mamnialogie,' p. 70. 

 Geoffroy St.-Hilaire and F. Cuvier, ' Hist. Nat. des Mamm.' 1824, torn. i. 



