the; sexual form of influence. 83 



groups, it will next be in place to consider the way in which each 

 method of influence acts and the different forms of action thai il 

 assumes in producing results under each principle. 



1. The Forms 0} the Conjunctional Method 0} each 0} the Four Principles. 



Producing demarcation of habit udinal Producing intensified divergence in 

 groups: habits of groups: 



Conjunctional partition. ( 'onjum tional < lection. 



Family partition. Sexual election. 



Social partition. Social election. 



Filio-parental election. 



Producing demarcation of racial groups: Producing intensified divergence in 



racial characters: 

 Conjunctional isolation. ( onjunctional selection. 



Sexual isolation. Sexual selection. 



Social isolation. Social selection. 



Filio-parental selection. 



The conjunctional method of influence is due to the need of coordi- 

 nation between one sex and the other in the intergenerating group, 

 between each member and the others in an associating group, and 

 between the parents and offspring in each family group. 



2. The Sexual Form of Selection, Election, and Isolation. 



Sexual selection is due to the necessity for coordination between the 

 sexual instincts and palpable qualities of the individual of either sex 

 and the instincts and palpable qualities of the other sex, in order to 

 secure propagation with survival in subsequent generations. It is 

 often assumed that in creatures lower than man sexual selection may 

 be effective in establishing the normal standards of prowess and dis- 

 play in the male sex, but that it avails very little in determining the 

 standards of attainment in the female sex. This is in a considerable 

 degree true of species in which the male is the party that seeks and 

 calls for a mate; but even in these species the answering call of the 

 female is often a necessary feature in the attainment of suitable mat- 

 ing; and the hen-bird that has lost her voice goes desolate. In some 

 species of insects the call for a mate comes from the male, and the part 

 of the female is to respond by leaving its distant hiding-place and com- 

 ing to the male. The methods of one such species are described in 

 my paper on Intensive Segregation, reproduced in Appendix II of this 

 volume. 



Sexual election is due to the necessity for coordination between the 

 acquired habits and standards of the individual of either sex and 

 the sexual instincts, as well as the acquired habits and standards of 



