ON THE CAPACITY FOR FERTILIZATION AFTER 

 THE INITIATION OF DEVELOPMENT. 1 



CARL R. MOORE. 



I. AN ATTEMPT TO FERTILIZE SEA-URCHIN EGGS SUBSEQUENT 

 TO HYPERTONIC PARTHENOGENESIS. 



CONTENTS. 



I. Introduction 2 5& 



II. Material and Methods 261 



III. Observations of Living Material - 262 



1. Fertilization after Exposure to Hypertonic Sea-water 263 



2. Fertilizin and Fertilization . 275 



3. Conclusions of Section III 278 



IV. Observations from Preserved Material. ... 279 



1. Insemination Subsequent to an Exposure to the Weaker Solution 279 



2. Insemination Subsequent to an Exposure to the Stronger Solution 282 



(a) Penetration of the Spermatozoon 284 



3. Insemination of Pure Cultures of Isolated Blastomeres 285 



4. Conclusions of Section IV 287 



V. Discussion 289 



VI. Summary. . 293 



VII. Literature Cited. . . . 294 



I. INTRODUCTION. 



The purpose of the present paper is to present a part of the 

 results of a study of the capacity for fertilization of eggs of the 

 sea-urchin (Arbacia punctulata) after the initiation of develop- 

 ment by artificial agents. A previous paper 2 by the writer has 

 dealt with some of the phenomena encountered in an attempt to 

 fertilize the eggs of Arbacia after a treatment with certain arti- 

 ficial stimuli, e. g., butyric acid and heat. The ideas involved 

 resolve themselves into the question can eggs that have been 

 activated by artificial parthenogenetic agents, be fertilized by 

 spermatozoa of the same species; or does activation by hyper- 

 tonic sea-water preclude fertilization as in the case of sperm 

 activation ? 



iprom the Marine Biological Laboratory, Wood's Hole, Mass., and the Hull 

 Zoological Laboratory. University of Chicago. 



2 Moore, '16. 



258 



