SEXUAL SELECTION 653 



With the adult musk ox {Ovihos moschaius) the horns 

 of the male are larger than those of the female, and in the 

 latter the bases do not touch." In regard to ordinary 

 cattle Mr. Blyth remarks: "In most of the wild bovine 

 animals the horns are both longer and thicker in the 

 bull than in the cow, and in the cow-banteng {Bos son- 

 daicus) the horns are remarkably small, and inclined much 

 backward. In the domestic races of cattle, both of the 

 humped and humpless types, the horns are short and thick 

 in the bull, longer and more slender in the cow and ox ; and 

 in the Indian bufEalo they are shorter and thicker in the 

 bull, longer and more slender in the cow. In the wild gaour 

 {B. gaurus) the horns are mostly both longer and thicker in 

 the bull than in the cow." " Dr. Forsyth Major also informs 

 me that a fossil skull, believed to be that of the female Bos 

 etruscus, has beea found in the Val d'Arno, which is wholly 

 without horns. In the Rhinoceros sirnus, as I may add, the 

 horns of the female are generally longer but less powerful 

 than in the male; and in some other species of rhinoceros 

 they are said to be shorter in the female. " From these va- 

 rious facts we may infer as probable that horns of all kinds, 

 even when they are equally developed in the two sexes, 

 were primarily acquired by the male in order to conquer 

 other males, and have been transferred more or less com- 

 pletely to the female. 



The effects of castration deserve notice, as throwing light 

 on this same point. Stags after the operation never renew 

 their horns. The male reindeer, however, must be ex- 

 cepted, as after castration he does renew them. This fact, 

 as well as the possession of horns by both sexes, seems at 

 first to prove that the horns in this species do not constitute 

 a sexual character;" but as they are developed at a very 



'■* Bicbardson, "Fauna Bor. Americana," p. 278. 



« "Land and "Water," 1867, p. 346. 



'• Sir Andrew Smith, "Zoology of S. Africa," pi. xix. Owen, "Anatomy 

 of Vertebrates," vol. iii. p. 624. 



" This is the conclusion of Seidlitz, "Die Darwin'sche Theorie," 1871, 

 p. 47. 



