Chap. XY. 
SEXUALLY-LIMITED INHERITANCE. 
159 
success lias quickly followed the order. Now the lop- 
ping of the comb must be sexually limited in its trans- 
mission, otherwise it would prevent the comb of the 
male from being perfectly upright, which WDuld be 
abhorrent to every fancier. On the other hand the 
uprightness of the comb in the male must likewise be 
a sexually-limited character, otherwise it would prevent 
the comb of the female from lopping over. 
From the foregoing illustrations, we see that even 
with almost unlimited time at command, it would be 
an extremely difficult and complex process, though 
perhaps not impossible, to change through selection 
one form of transmission into the other. Therefore, 
without distinct evidence in each case, I am unwilling 
to admit that this has often been effected with natural 
species. On the other hand by means of successive 
variations, which were from the first sexually limited 
in their transmission, there would not be the least 
difficulty in rendering a male bird widely different in 
colour or in any other character from the female ; the 
latter being left unaltered, or slightly altered, or specially 
modified for the sake of protection. 
As bright colours are of service to the males in their 
rivalry with other males, such colours would be selected, 
whether or not they were transmitted exclusively to the 
same sex. Consequently the females might be expected 
often to partake of the brightness of the males to a 
greater or less degree ; and this occurs with a host of 
species. If all the successive variations were trans- 
mitted equally to both sexes, the females would be 
undistinguishable from the males; and this likewise 
occurs with many birds. If, however, dull colours were 
of high importance for the safety of the female during 
incubation, as with many ground birds, the females 
which varied in brightness, or which received through 
