STUDIES OF FERTILIZATION* 



V. THE BEHAVIOR OF THE SPERMATOZOA OF NEREIS AND ARBACIA 

 WITH SPECIAL REFERENCE TO EGG-EXTRACTIVES 



FRANK R. LILLIE 



The Hull Zoological Laboratory, University of Chicago 



FIVE FIGURES 



CONTENTS 



I. Introduction 516 



II. Activation phenomena 519 



A. Nereis 519 



1. The aggregation reaction 519 



2. Individual movements of the sperm 522 



3. 'Freshness' 523 



4. Temperature 524 



5. Chemical constitution of the medium 525 



a. Acids 526 



b. Alkalis '. 528 



c. Alcohol and ether 529 



6. Hypo- and hyper-tonicity 530 



B. Arbacia 531 



III. Aggregation phenomena. 532 



A. Nereis 533 



1. Aggregation with reference to COa 533 



2. Interpretation of the aggregation reaction 538 



3. Reaction to other acids 541 



4. Behavior with reference to alkalis 541 



5. Reactions to other substances 542 



6. Thermotaxis 543 



7. Thigmotaxis 543 



8. Variations of reaction 544 



9. Chemotaxis to egg-secretions 546 



B. Arbacia 546 



1 The earlier studies of this series bore the general title "Studies of fertilization 

 in Nereis." 



515 



THE JOURNAL OF EXPERIMENTAL ZOOLOGY, VOL. 14, NO. 4 



