434 REPRODUCTION OF SALP.E. 



rous individuals. These last are so unlike the individuals of the 

 separate race, that they might be regarded as distinct species. 

 Nevertheless it is found that the associated individuals produce 

 eggs, from which the solitary Salpus are developed ; and that 

 these in their turn produce chains of eggs, from which the riband- 

 like groups originate ; these last, again, giving birth to the 

 solitary race ; and so on alternately. Thus, a Salpa which 

 differs equally from its parent and its own progeny, resembles its 

 grand-parent, its grand -children, and its own brethren. 



