Self-Fertilization Induced by Artificial Means. 143 



were put into ether-solutions of 3, 2, i, 0.7, 0.5 per cent., and 

 were removed to sea-water after 10, 20 and 30 minutes. 



The table shows that eggs segmented in all of the solutions, 

 best however in the stronger solutions, although in one case the 

 eggs became so injured by the ether that they did not develop 

 further than the segmentation stages. In a check series, in which 

 the self-fertilized eggs were put into sea-water, about ten per cent, 

 of the eggs segmented. There may have been some source of con- 

 tamination, or else, and this seems more likely since the indi- 

 vidual had been isolated 20 hours, self-fertilization took place 

 on a larger scale than usual. 



Experiment IF. Eggs and sperm were mixed in ether-solutions 

 of 4, 2, I, 0.5 per cent. 



Ether 2 min. 4 min. 



4. o o ■ «*-,- 



2. 40 I 



I- 35 30 



0.5 5 I 



These results show that the 4 per cent, solution was too strong, 

 while the 0.5 per cent, solution appears to have been too weak. 

 The injurious action of the 4 per cent, solution appears to have 

 been mainly on the sperm rather than on the eggs, for these 

 eggs after they had been in sea-water 4 hours were capable of 

 being cross-fertilized, and 25 per cent, of them developed. 



Experiment V. Eggs and sperm were put into a 2 and into a 

 0.5 per cent, ether-solution and removed after 5 minutes. 



