290 THE PRINCIPLES OF Part II. 



the horns are developed later in life in this breed than 

 in ordinary sheep in which both sexes are horned. But 

 with domesticated sheep the presence or absence of 

 horns is not a firmly fixed character ; a certain proportion 

 of the merino ewes bearing small horns, and some of the 

 rams being hornless ; whilst with ordinary sheep hornless 

 ewes are occasionally produced. 



In most of the species of the splendid family of the 

 Pheasants, the males differ conspicuously from the 

 females, and they acquire their ornaments at a rather 

 late period of life. The eared pheasant (Crossoptilon 

 auritum), however, offers a remarkable exception, for 

 both sexes possess the fine caudal plumes, the large ear- 

 tufts and the crimson velvet about the head ; and I find 

 on enquiry in the Zoological Gardens that all these 

 characters, in accordance with our rule, appear very 

 early in life. The adult male can, however, be distin- 

 guished from the adult female by one character, namely 

 by the presence of spurs ; and conformably with our 

 rule, these do not begin to be developed, as I am assured 

 by Mr. Bartlett, before the age of six months, and even 

 at this age, can hardly be distinguished in the two 

 sexes. 28 The male and female Peacock differ con- 



period of life, conformably with our rule, than in the Welch sheep, in 

 which both sexes are horned. 



28 In the common peacock (Paro cristatus) the male alone possesses 

 spurs, whilst botli sexes of the Java peacock (P. muticus) offer the 

 unusual case of being furnished with spurs. Hence I fully expected 

 that in the latter species they would have been developed earlier in life 

 than in the common peacock ; but M. Hegt of Amsterdam informs me, 

 that with young birds of the previous year, belonging to both species, 

 compared on April 23rd, 1869, there was no difference in the develop- 

 ment of the spurs. The spurs, however, were as yet represented merely 

 by slight knobs or elevations. I presume that I should have been in- 

 formed if any difference in the rate of development had subsequently 

 been observed. 



