Ohap. XVIII. Mammals — Ornamental Colours. 539 



" manque reellement pas d'el6gaiice."^' "When the animal is 

 excited all the naked parts become much more vividly tinted. 

 Several authors have used the Strongest expressions in de- 

 Boribing these resplendent colours, vfhich they compare wiih 

 those of the most brilliant birds. Another remarkable pecu- 

 liarity 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. 69.) In 

 the adult females and in the young of both sexes these protuber- 

 ances are scarcely perceptible ; and the naked parts are much 

 less bright 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 

 nrighter coloured than the female, and differs from the young of 

 both sexes. But as with some few birds it is the female which is 

 brighter coloured than the male, so with the Ehesus monkey 

 {Mucacus r/iesus) the female has a large surface of naked skin 

 round the tail, of a brilliant carmine red, which, as I was 

 assured by the keepers in the Zoological Gardens, periodically 

 becomes even yet more vivid, and her face also is pale red. On 

 the other hand, in the adult male and in the young of both sexes, 

 (as I saw in the Gardens) neither the naked skin at the posterior 

 end of the body, nor the face, shew a trace of red. It appears, 

 however, from some published accounts, that the male does occa- 

 sionally, or during certain seasons, exhibit some traces of the red. 

 Although he is thus less ornamented than the female, yet in the 

 larger size of his body, larger canine teeth, more developed 

 whiskers, more prominent superciliary ridges, he follows the 

 common rule of the male excelling the female. 



I have now given all the cases known to me of a difference in 

 colour between the sexes of mammals. Some of these may be 

 the result of variations confined to one sex and transmitted to 

 the same sex, without any good being gained, and therefore 

 without the aid of selection. We have instances of this with 

 our domesticated animals, as in the males of certain cats being 

 rusty-red, whilst the females are tortoise-shell coloured. Analo- 

 gous cases occur in nature : Mr. Bartlett has seen many black 

 varieties of the jaguar, leopard, vulpine plialanger, and wombat; 



^' Gervais, ' Hist. Nat. iles Mjim- Desmiirest, ' Mumm.ilogie,' ji. 70. 

 n.ifferes,' 1854, p. 103. Figures are Genllriiy St.-Hiliure :ui(l I''. Cuviei, 

 given of the skull of the niiJe. Also ' Hist. Niit. Jes Mamm.' 1824, ton . i 



