R HAP. XVIII. ORNAMENTAL COLOURS. 293 
yellow beard. “ Toutes les parties superieures de leurs 
euisses et le grand espace nu de leurs fesses sont 
' egalement colores du rouge le plus vif, avec un 
melange de bleu qui ne manque reellement, pas 
1 ^ elegance.” 31 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 
Hre most brilliant birds. Another most remarkable 
Peculiarity is that when the great canine teeth are fully 
developed, immense protuberances of bone are formed 
°n each cheek, which are deeply furrowed longitudinally, 
a rid the naked skin over them is brilliantly-coloured, as 
•i’rst described. (Fig. G7.) In the adult females and in 
lire 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. 
1 n the adult female, however, the nose at certain regular 
rtrtervals 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- 
I'Ts in a greater degree from the young of both sexes, 
ll'it as a reversed style of colouring is characteristic of 
Urn two sexes with some few birds, so with the Rhesus 
donkey ( Maeacus rhesus) the female has a large surface 
°f naked skin round the tail, of a brilliant carmine red, 
"Pick periodically becomes, as I was assured by the 
Peepers in the Zoological Gardens, even more vivid, 
an d her face is also pale red. On the other hand with 
!1 Gervais, 1 Hist. Nat. des Mammif eres,’ 1851, p. 103. Figures aro 
S'ven of the skull of the male. Desmarest, ‘ Mammalogie,’ p. 70. 
Geofiroy St.-Hilaire and F. Cuvier, ‘ Hist. Nat. des Mamm.’ 1821, tom. i. 
