SEXUAL SELECTION. 265 



horns, I find that the horns first appear at periods varying 

 from nine months after birth in the roebuck to ten, twelve 

 or even more moaths in the stags of the six other and 

 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 likewise common to both sexes in 

 this one species alone. 



In several kinds of antelopes only the males are provided 

 with horns, while in the greater number both sexes bear 

 horns. With respect to the period of development, Mr. 

 Blyth informs me that there was at one time in the Zoo- 

 logical Gardens a young koodoo (Ant. strepsiceros) of 

 which the males alono are horned, and also the young of a 

 closely allied species, the eland (Ant. ureas), in which both 

 sexos are horned. Now it is in strict conformity with our 

 rule that in the young male koodoo, although ten months 

 old, the horns were remarkably sm>iU, considering the size 

 ultimately attained by them; whila in the young male 

 eland, although only three months old, the "horns were 

 already very much larger than in the koodoo. It is also a 

 noticeable fact that in the prong-horned antelope f only a 

 few of the females, about one in live, have horns, and 

 these are in a rudimentary state, though sometimes above 

 four inches long; so that as far as concerns the possession 

 of horns by the males alone, this species is in an inter- 

 mediate condition and the horns do not appear until about 

 five or six months after birth. Therefcre in comparison 



* I am much obliged to Mr. Cupples for haviug" made inquiries for 

 me in regard to the Roebuck and Red Deer of Scotland from Mr. 

 Robertson, the experienced head-forester to the Marquis of Breadal- 

 bane. In regard to Fallow-deer, I have to thank Mr, Eyton and 

 others for information. For the Cervus dices of North America, see 

 " Land and Water," 1868, pp. 221, 254; and for the C. Vl v ginianus 

 and strongyluceros of the same continent, see J. D. Caton, in ''Ottawa 

 Acad. of Nat. Sc.," 1868, p. 13. For Cervus Eldi of Pegu, see Lieut. 

 Beavan, '-Proc. Zoolog. Soc.," 1867, p. 762. 



f A niilocapra Americana. I have to thank Dr. Canfield for infor- 

 mation with respect to the horns of the female; see also his paper in 

 " Proc. Zoolog. Soc.," 1866, p. 109. Also Owen, " Anatony of Verte- 

 brates," vol. iii, p. 627. 



