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. Blyth 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 afterbirth. 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 find on enquiry , 27 that 
25 Antilocaprct Americana. Owen, ‘Anatomy of Vertebrates,’ vol. 
iii. p. 627. 
26 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 horny 
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 6th, so 
that in this instance the development of the horns occurred at a later 
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