252 Studies in the Plijisiolofiji of Fertilization 



of the few larvae present in the Bjb culture settled down, and very few 

 in the Aja, whereas a large proportion fixed themselves in the cross- 

 fertilized lots. The next examination was made eight days afterwards, 

 when no individuals derived from self-fertilized c'ggs were found to have 

 survived, while those from cross-fertilizations were growing rapidly. 



The second experiment, made on the same lines as the first, is 

 recorded in Table XIII. 



In this case, of the self-fertilizations only C/c gave enough seg- 

 menting eggs to make observations on. The rate of early segmentation 

 was here slightly slower than in the crosses, and the time of hatching 

 was considerably later. Moreover the G/c larvae hatched out were not 

 so vigorous as those of the crosses, which were about equal to one 

 another in this respect. Eight days later one or two only of the self- 

 fertilized individuals which had fixed themselves were surviving, and 

 after 20 days these were found to have died ofi". 



It should be mentioned here that after the majority of the larvae 

 had settled down in their different dishes, the latter were washed in a 

 stream of sea-water to remove all larvae which had failed to fix them- 

 selves together with all that had settled on the surface-film'. The 

 dished were then sunk in a large tank of water, so that the different 

 cultures should be exposed to identical conditions during the growth of 

 the young animals. 



In the last column of Table XIII it will be noticed that after 

 20 days fewer of the crosses G/a and A/c were living than of B/c and 

 C/fc. Nevertheless, the former had shown a slighth' quicker rate of 

 early segmentation than the latter, and the time of hatching o{ A/c had 



' In later experiments, where a strict comparison between the states of development 

 in the various cultures was not wanted, the animals which settled on the surface-film were 

 not discarded. They were indeed in most cases found to grow more rapiilly than tliose on 

 the walls of the dishes. 



