xii PROBLEMS OF FERTILIZATION 



PAGE 



FIG. 14. REACTION OF A SPERM SUSPENSION OF Nereis 

 TO A DROP OF i PER CENT Co 2 SEA- 

 WATER 105 



FIG. 15. DIAGRAM OF THE REACTION OF SPERMATOZOA OF 

 Nereis TO A DROP OF i PER CENT Co 2 IN SEA- 

 WATER 106 



FIG. 1 6. CURVE OF FERTILIZING POWER OF PERFECTLY 



FRESH SPERM SUSPENSIONS OF Arbacia . . 135 



FIG. 17. CURVE OF FERTILIZING POWER OF SPERM SUS- 

 PENSIONS OF Arbacia ABOUT 20 MINUTES OLD 137 



FIG. 18. IMBIBITION OF WATER BY Arbacia EGGS IN 



DILUTED SEA-WATER 150 



FIG. 19. CURVE OF FERTILIZATION SUPERIMPOSED UPON 



BUTYRIC ACID TREATMENT IN Arbacia . 168 



