266 THE BIOLOGY OF THE SEASONS 



If the breeding-season be of long duration, the males must 

 greatly outnumber the females to secure this fortuitous 

 proximity ; but if all of the females swarm within a few 

 days, very much fewer males will suffice to accomplish 

 this purpose." 



" We have advanced beyond the period in the history of 

 biology when one had but to discover an advantage to 

 determine a cause ; but that some such cause may have 

 contributed to shorten the breeding-season in such animals 

 as the Atlantic, Pacific, and Japanese palolo worms is 

 shown by the fact that more eggs are fertilised when males 

 are near the female than when they are far away." 



Thus we find in the palolo a fine instance, on the one 

 hand, of evading the penalty so often imposed on repro- 

 duction, and, on the other hand, of securing prodigal 

 multiplication while economising reproductive expenditure. 



