Chap. VIII. SEXUAL SELECTION. 289 



provided with horns, whilst in the greater number both 

 sexes have horns. With respect to the period of de- 

 velopment, Mr. Blvth 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, although arrived at the age of ten 

 months, 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 worth notice that in the prong-horned antelope, 25 

 in which species the horns, though present in both 

 sexes, are almost rudimentary in the female, they do not 

 appear until about five or six months after birth. With 

 sheep, goats, and cattle, in which the horns are well 

 developed in both sexes, though not quite equal in size, 

 they can be felt, or even seen, at birth or soon after- 

 wards. 26 Our rule, however, fails in regard to some 

 breeds of sheep, for instance merinos, in which the rams 

 alone are horned ; for I cannot rind on enquiry, 27 that 



25 Antilocaiyra Americana. Owen, 'Anatomy of Vertebrates,' vol. 

 iii. p. 627. 



2fi I have been assured that the horns of the sheep in North Wales 

 can always be felt, and are sometimes even an inch in length, at birth. 

 With cattle Youatt says (' Cattle/ 1834, p. 277) that the prominence of 

 the frontal bone penetrates the cutis at birth, and that the homy 

 matter is soon formed over it. 



27 I am greatly indebted to Prof. Victor Cams for having made 

 inquiries for me, from the highest authorities, with respect to the 

 merino sheep of Saxony. On the Guinea coast of Africa there is a 

 breed of sheep in which, as with merinos, the rams alone bear horns ; 

 and Mr. Winwood Eeade informs me that in the one case observed, a 

 young ram born on Feb. 10th first showed horns on March Gth, so 

 that in this instance the development of the horns occurred at a later 

 VOL. I. U 



