SEXUAL SELECTION. 
319 
Cb. 
Ap. VIII. 
m ore fertile pairs producing a larger number of off- 
ering, and these from their mere number will have the 
“est chance of surviving, and will transmit their ten- 
ancy to greater fertility. The only check to a con- 
tinued augmentation of fertility in each organism seems 
to be either the expenditure of more power and the 
heater risks run by the parents that produce a more 
’’Utnerous progeny, or the contingency of veiy numerous 
e Sgs and young being produced of smaller size, or less 
v *gorons, or subsequently not so well nurtured. To 
strike a balance in any case between the disadvantages 
"'hid, follow from the production of a numerous pro- 
geny, and the advantages (such as the escape of at least 
s °iue individuals from various dangers) is quite beyond 
,J ’ lr power of judgment. 
When an organism has once been rendered extremely 
Wtile, how its fertility can be reduced through natural 
Election is not so clear as how this capacity was first 
Squired. Yet it is obvious that if individuals of a 
8 Pecies, from a decrease of their natural enemies, were 
^ a bitually reared in larger numbers than could be sup- 
ported, all the members would suffer. Nevertheless the 
°%>ring from the less fertile parents would have no 
Effect advantage over the offspring from the more fer- 
tile parents, when all were mingled together in the 
district. All the individuals would mutually tend 
P' starve each other. The offspring indeed of the less 
|®rtile parents would lie under one great disadvantage, 
f ° 1 ' from the simple fact of being produced in smaller 
’(Umbers, they would be the most liable to extermina- 
tion. Indirectly, however, they would partake of one 
§ r eat advantage ; for under the supposed condition of 
Severe competition, when all ivere pressed for food, it is 
^treinely probable that those individuals which from 
^'Uie variation in their constitution produced fewer eggs 
