DOMINATIONAL AND IMPREGNATIONAL INFIrUBNCES. 87 



overcome, and forestall rivals of the same species in taking possession 

 of mates or of resources and in seizing on opportunities. The import- 

 ance of conflict and rivalry between individuals of the same group in 

 gaining possession of resources and mates was discussed in my paper 

 on Intensive Segregation under the term that I now use. It has since 

 then been discussed by Karl Pearson in his "Grammar of Science," 

 under the terra "inter-group selection." The chief objection to his 

 term is that it ought naturally to include all the forms of what I have 

 called "reflexive selection;" but this is not in accordance with the 

 definitions he has given. 



Dominational selection is due to inherited powers for overcoming 

 rivals giving a larger share in propagation and survival through con- 

 trol of resources and mates. 



Dominational election is due to acquired powers for overcoming 

 rivals giving superior success and influence in the associating group. 

 As prepotence is determined entirely by inherited powers, domina- 

 tional election can have no influence on prepotence. Severe 

 competition with domination is a condition that gives importance 

 to isolation and partition, but these principles are not introduced 

 without other causes, such as migration or transportation. 



6. The Forms of the Impregnational Method of Influence. 

 Producing demarcation of racial Producing intensification of racial 



groups: groups: 



Impregnational isolation. Impregnational selection. 



Dimensional isolation. Dimensional interselection. 



Structural isolation. Structural interselection. 



Potential isolation. Potential selection. 



Segregate fecundity. Fecundal selection. 



Segregate vigor. 

 Segregate adaptation. 

 Segregate freedom from competition. 

 Segregate escape from enemies. 



The impregnational method of influence is due to the need of coor- 

 dination between the size, structure, sexual elements, and functions 

 of each sex and the related characters of the other sex, in any inter- 

 generating group, in order to secure a sufficient number of impreg- 

 nated germs with the least expenditure and waste. Inasmuch as 

 the influences shaping impregnation are inherited and not acquired, 

 their chief effects are on racial rather than habitudinal groups. We 

 therefore have no occasion to consider impregnational partition and 

 election. 



Of the forms of impregnational isolation, the first five as given above 

 were so fully considered in my paper on Divergent Evolution* that it 



* See Appendix I, where part of the paper is reproduced. 



