Chap. VIII. 
SEXUAL SELECTION. 
275 
led to the much more frequent development of secon- 
dary sexual characters in the male than in the female. 
But the development of such characters will have been 
much aided, if the conclusion at which I arrived after 
studying domesticated animals, can be trusted, namely, 
that the male is more liable to vary than the female. 
I am aware how difficult it is to verify a conclusion of 
this kind. Some slight evidence, however, can be gained 
by comparing the two sexes in mankind, as man has 
been more carefully observed than any other animal. 
During the Novara Expedition 15 a vast number of mea- 
surements of various parts of the body in different races 
were made, and the men were found in almost every 
case to present a greater range of variation than the 
women; but I shall have to recur to this subject in 
a future chapter. Mr. J. Wood, 16 who has carefully 
attended to the variation of the muscles in man, puts 
in italics the conclusion that “ the greatest number of 
“ abnormalities in each subject is found in the males. 5 ' 
He had previously remarked that “ altogether in 102 
“ subjects the varieties of redundancy were found to 
“ be half as many again as in females, contrasting 
“ widely with the greater frequency of deficiency in 
“ females before described. 55 Professor Macalister like 
wise remarks 17 that variations in the muscles “are 
“ probably more common in males than females. 55 
Certain muscles which are not normally present in man- 
kind are also more frequently developed in the male 
than in the female sex, although exceptions to this rule 
15 • ‘ Reise der Novara: Anthropolog. Theil/ 1867, s. 216-269. The 
results were calculated by Dr. Weisbach from measurements made by 
Drs. K. Scberzer and Schwarz. On the greater variability of the males 
of domesticated animals, see my ‘Variation of Animals and Plants 
under Domestication/ vol. ii. 1868, p. 75. 
16 ‘Proceedings Royal Soc.’ vol. xvi. July, 1868, p. 519 and 524. 
17 ‘ Proc. Royal Irish Academy/ vol. x. 1868, p. 123. 
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