LARVAE OF ARBACIA PUNCTULATA 



413 



males and divided the eggs of each into five portions. The 

 sperm from five males was treated in the same way, and from 

 each portion of sperm, one division of eggs from each female was 

 fertilized. This resulted in 25 cultures which he observed for 

 three days and noted the variations in the different cultures. 



In the present experiment, since it was desired to take the 

 usual number of measurements in each culture every day, only 

 four males (I, II, III and IV), and four females (A, B, C and 

 D) were selected. In this way 16 cultures were procured and 

 observed for the usual five days. 



The following measurements were obtained: 



Experiment 21. June 27, 1915 



Plot 20 



A 



