288 SEXUAL SELECTION : MAMMALS. Part II. 



and the black spots on the ears, all much more dis- 

 tinct. We have seen that in this species the crests and 

 tufts of hair are likewise more developed in the male 

 than in the hornless female. The male, as I am 

 informed by Mr. Blyth, without shedding his hair, 

 periodically becomes darker during the breeding-sea- 

 son. Yonns: males cannot be distino-uislied from youns^ 

 females until above twelve months old; and if the 

 male is emasculated before this period, he never, accord- 

 ing to the same authority, changes colour. The import- 

 ance of this latter fact, as distinctive of sexual colouring, 

 becomes obvious, when we hear^* that neither the red 

 summer-coat nor the blue winter-coat of the Yiro-inian 



o 



deer is at all affected by emasculation. With most or 

 all of the highly-ornamented species of Tragelaphus the 

 males are darker than the hornless females, and their 

 crests of hair are more fully developed. In the male 

 of that magnificent antelope, the Derhyan Eland, the 

 body is redder, the whole neck much blacker, and the 

 w^hite band which separates these colours, broader, 

 than in the female. In the Cape Eland also, the male 

 is slio'htlv darker than the female.^^ 



In the Indian Black-buck (A. hezoartica), which belongs 

 to another tribe of antelopes, the male is very dark, almost 

 black; whilst the hornless female is fawn-coloured. We 

 have in this species, as Mr. Blyth informs me, an exactly 

 parallel series of facts, as w ith the Portax jyicia, namely in 

 the male periodically changing colour during the breed- 



-* Judge Caton, in ' Trans. Ottawa Acad, of Nat. Sciences,' 1868, 

 JD. 4. 



25 Dr. Gray, ' Cat. of Mamm. in Brit. Mus.' part iii, 1852, p. 134-142 ; 

 also Dr. Gray, ' Gleanings from the Menagerie of Knowsley,' in which 

 there is a splendid drawing of the Oreas derbianus : see the text on 

 Tragelaphus. For the Cape Eland (Oreas canna), see Andrew Smith, 

 ' Zoology of S. Africa,' pi. 41 and 42. There are also many of these 

 antelopes in the Zoological Society's Gardens. 



