LARVAE OF ARBACIA PUNCTULATA 



415 



Plot 23 



of the sperm is, however, also evident, since in all the sets, the 

 order of the cultures as to size is identical, IV, I, II, III, except 

 in C where III and II are reversed. This may be ascribed to 

 experimental error in handling or measuring since no other 

 explanation can be offered. At the close of the experiment, 

 however, the order of all the sets is the same, being I, II, III, IV. 

 In all combinations except C (Plot 23), cultures I, II and III 



Figs. 146 to 152 Experiment 21. Eggs from different females fertilized with 

 sperm from different males. 



Fig. 147 21 AI, figure 148 21 All, figure 149 21 AIII, figure 150 21 AIV, 24 

 hrs. Specimens showing the tendency for appearance of four rods in place of 

 three on the left side of a large number of larvae of all the cultures from eggs of 

 Female A. 



Fig. 151 21 Bill, 24 hrs. Specimen with unusually widely spread arms. 

 Present in a large proportion of all the cultures fertilized with sperm from Male 

 III. 



Fig. 152 21 Bill, 24 hrs. Specimen with anal arms and body-rods parallel. 

 This type appeared in about 1 per cent of all cultures from Male III. 



