Chap. VIII.] SEXUAL SELECTION. 279 



distinct sections of the family and inhabiting different 

 regions, in which the stags alone bear horns, I find that 

 the horns first appear at periods varying from nine months 

 after birth in the roebuck to ten or twelve more months 

 in the stags of the six other larger species.^* But with 

 the reindeer the case is widely different, for as I hear from 

 Prof. Nilsson, who kindly made special inquiries for me 

 in Lapland, the horns appear in the young animals within 

 four or five weeks after birth, and at the same time in 

 both sexes. So that here we have a structure, developed 

 at a most unusually early age in one species of the family, 

 and common to both sexes in this one species. 



In several kinds of antelopes the males alone are pro- 

 vided with horns, while in the greater number both sexes 

 have horns. With respect to the period of development, 

 Mr. Blyth informs me that there lived at one time in the 

 Zoological Gardens a young koodoo (Ant. strepsiceros), 

 in which species the males alone are horned, and the 

 young of a closely-allied species, viz., the eland {Ant. 

 oreas), in which both sexes are horned. Now in strict 

 conformity with our rule, in the young male koodoo, al- 

 though arrived at the age of ten months, the horns were 

 remarkably small considering the size ultimately attained 

 by them : while in the young male eland, although only 

 three months old, the horns were already very much larger 

 than in the koodoo. It is also worth notice that in the 



^^ I am much obliged to Mr. Cupples foi' having made inquiries for 

 me in regard to the Roebuck and Eed Deer of Scotland from Mr. Rob- 

 ertson, the experienced head-forester to the Marquis of Breadalbane. In 

 regard to Fallow-deer, I am obliged to Mr. Eyton and others for informa- 

 tion. For the Cerj^ws a?ce5 of North America, see ' Land and Water,' 1868, 

 pp. 221 and 234 ; and for the C. Virginianus and strongyloccros of the 

 same continent, see J. D. Caton, in ' Ottawa Acad, of Nat. Sc' 1868, p. 

 13. For Cervus IJldl q{ Pegu, sae Lieut. Beavan, 'Proc. Zoolog. Soc' 

 ISGY, p. '762. 



