28o 



THE EVOLUTION OF SEX. 



offspring which remain associated with the parents ; the occur- 

 rence of genuine pairing beyond the Hmits of the sexual period : 

 the estabHshment of distinct families, with unmistakable affec- 

 tion between parents, offspring, and relatives; and lasdy, the 

 occurrence of animal varieties wider than the family, — mark 

 important steps in the evolution of both egoism and altruism. 



Ideal unity. 



society, 



family. 



offspring. 



mates. 



N V R 



Protoplasmic identity. 

 Diagrammatic Representation of the Relations between Nutritive, 

 Self-Maintaining, or Egoistic, and Reproductive, Species- 

 Regarding, or Altruistic Activities. 



The diagram sums up the important facts. There are two 

 divergent lines of emotional and practical activity, — hunger, 



