290 
THE PRINCIPLES OF 
Paht 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 ( Grossoptilon 
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 ( Pavo cr [status) the male alone possesses 
spurs, whilst both 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. 
