64 THE EVOLUTION OF LIVING BEINGS. 



of a specific chemical substance ;in suppport of this, one 

 might bring forward the estabUshed fact that different 

 „species" of fishes are characterised by specific prota- 

 mines in their male gametes. 



I wish it to be distinctly understood that I am neither 

 pleading for the view that a homozygous individual is 

 an entity, nor for the view that it is a complex of more 

 or less independant units ; I am simply stating the fact, 

 regrettable as it is, that we know nothing about it. 



