C HAI>. VIII. 
SEXUAL SELECT IOX. 
257 
°f life, and tlie male has more highly developed sense 
° r locomotive organs than the female, it may be that 
those in their perfected state are indispensable to the 
’Hale for finding the female ; but in tl^e vast majority 
°f cases, they serve only to give one male an advan- 
tage over another, for the less well-endowed males, 
time were allowed them, would succeed in pair- 
ing with the females; and they would in all other 
Aspects, judging from the structure of the female, he 
dually well adapted for their ordinary habits of life. 
In such cases sexual selection must have come into 
notion, for the males have acquired their present struc- 
ture, not from being better fitted to survive in the 
struggle for existence, but from having gained an ad- 
jutage over other males, aud from having transmitted 
this advantage to their male offspring alone. It was the 
lr uportance of this distinction which led me to designate 
this form of selection as sexual selection. So again, 
h the chief service rendered to the male by his pre- 
luensile organs is to prevent the escape of the female 
before the arrival of other males, or when assaulted by 
them, these organs will have been perfected through 
8e Xual selection, that is by the advantage acquired by 
Cei 'tain males over their rivals. But in most cases it 
ls scarcely possible to distinguish between the effects 
°f natural and sexual selection. Whole chapters could 
eas dy he filled with details on the differences between 
the sexes in their sensory, locomotive, and prehensile 
? r gan s . As, however, these structures are not more 
mteresting than others adapted for the ordinary pur- 
poses of life, I shall almost pass them over, giving only 
a low instances under each class. 
there are many other structures and instincts which 
just have been developed through sexual selection — 
Sll ch as the weapons of offence and the means of defence 
vol. i. 
s 
