FERTILIZATION OF NEREIS. 2OI 



was stopped by the end of the Nereis " Run" and as the observa- 

 tions in regard to maturation were complete it seems to me to be 

 best to present the work in its present form. 



TABLES. 



The headings are mostly self-explanatory. Under Polar Body 

 Formation and Cleavage a plus sign ( + ) indicates that the 

 process was observed and a minus ( ) the reverse. Control 

 No. i are eggs from the same lots as in the experiments fertilized 

 a few minutes before the experiment began from the sperm of 

 the same male used. Control 2 are eggs not operated on from 

 the coverslip and Control 3 are eggs of the same inseminated lot 

 mixed with chinese ink from which those placed on the cover 

 slip were taken. The plus sign ( + ) under Controls I and 3 

 indicates the practically 100 per cent, cleavage usually realized 

 with Nereis eggs. 



WESLEYAN UNIVERSITY, 

 January, 1920. 



LITERATURE CITED. 

 Just, E. E. 



'15 Initiation of Development in Nereis. BIOL. BULL., Vol. 28. 



Lillie, F. R. 



'n Studies of Fertilization in Nereis, I and II. Jour. Morph., Vol. 22. 



'15 Studies of Fertilization, VII. BIOL. BULL., Vol. 28. 



'ig Problems of Fertilization. University of Chicago Science Series. 



