!34 The Descent of M aft. Part H 



would lead to their development in that sex alone, in which 

 they first appeared in the progenitor of the whole Family. Now 

 in seven species, belonging to 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, twelve or even more 

 months in the stags of the six other and larger species. 39 But 

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

 Prof. Nilsson, who kindly made special enquiries 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, 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. strepskeros), of which the males alone are horned, 

 aud also the young of a closely-allied species, the eland (Ant. 

 oreus), 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, con- 

 sidericg 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 antelorje, 40 

 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 development of the horns in other antelopes, and from what 



39 I am much obliged to Mr. tinent, see J. D. Caton, in 'Ottawa 



Cupples for having made enquiries Acad, of Nat. Sc. 1868, p. 13. For 



for me in regard to the Roebuck Cervits Ehii of Pegu, see Lieut, 



and Red Deer of Scotland from Mr. Beavan, ' Proc. Zoolog. Soc.' 1867, 



Robertson, the experienced head- p. 762. 



forester to the Marquis of Breadal- i0 Antilocapra Americana. I have 



bane. In regard to Fallow-deer, I to thank Dr. Canfield for informa- 



have to thank Mr. Eyton and tion with respect to the horns of the 



others for information. For the female: see also his paper in ' Proc. 



Cervus alces of N. America, see Zooiog. Soc.' 1866, p. 109. Alsc 



'Land and Water,' 1868, pp. 221 Owen, 'Anatomy of VertebrateB, 



and 254 ; and for the C. Yirginianus vol. iii. p. 627. 

 md strongyJoceros of the same con- 



