30 Instinct and Intelligence 



swim about in the water until they meet with one 

 of the female cells, into which they pass ; fertili- 

 sation takes place by changes similar to those 

 which characterise the reproduction of the germ 

 cells of the higher orders of plants and animals. 

 From our point of view the interesting feature 

 in reference to the life-history of some of the 

 Volvocinse is the evidence it affords that, with 

 structural modifications in their protoplasm, 

 there is a corresponding alteration in the nature 

 of the work it performs. 



