REPRODUCTION AND GROWTH 281 



parent butterfish it is then but a short step to the building 

 of a nest as in the case of the fifteen-spined stickleback. 



(e) The survival of shore forms with pelagic larvae is 

 not entirely fortuitous, but sensitiveness to light acting in 

 conjunction with the movements of the surface waters tends 

 to lead a larva towards the environment suitable to its adult 

 existence. 



