SEXUAL, SELECTION. 229 



periods, varying from nine months after birth In the roebuclc, to 

 ten, twelve or even more months in the stags of the six other 

 and larger species.'" But with the reindeer the case is widely dif- 

 ferent; for, as I hear from Prof. Nilsson, who kindly made special 

 inquiries for me in Lapland, the horns appear in the young ani- 

 mals 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 like- 

 wise common to both sexes in this one species alone. 



In several kinds of antelopes, only the males are provided with 

 horns, whilst 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 Zoological Gardens a young koodoo 

 (Ant. strepsiceros), of which the males alone are horned, and also 

 the young of a closely-allied species, the eland (Ant. oreas), in 

 which both sexes 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 small, considering the size ultimately 

 attained by them; whilst 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," only a few of the females, about one in five, 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 intermediate condition, and 

 the horns do not appear until about five or six months after birth. 

 Therefore in comparison with what little we know of the develop- 

 ment of the horns in other antelopes, and from what we do know 

 with respect to the horns of deer, cattle, &c., those of the prong- 

 horned antelope appear at an intermediate period of life, — that is, 

 not very early, as in cattle and sheep, nor very late, as in the larg- 

 er deer and antelopes. The horns of sheep, goats, and cattle, 

 which are well developed in both sexes, though not quite equal in 



•™ I am much obliged to Mr. Cupples for having 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 alces of N. America, see 

 'Land and Water,' 1868, pp. 221 and 254; and for the C. Virginian us 

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

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

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



*> Antilocapra Americana. I have to thank Dr. Canfield for in- 

 formation with respect to the horns of the female: see also his paper 

 in 'Proc. Zoolog. Soc' 1866, p. 109. Also Owen, 'Anatomy of Verte- 

 brates,' vol. iii. p. 627. 



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