Echinoderm Hybridization. 



147 



To facilitate comparison I combine all the statistics together in 

 Table VII. 



TA B LE VII . Comparison of results of cross-fertilisation. 



The first results of 1910 did not tend to confirm those of 1909. As 

 I have already stated, another indication of Hipponoe dominance made 

 its appearance, this being the basket. This character seemed especially 

 difficult to control. The use of a greater amount of acid brought the 

 results of the previous summer. One interesting thing in the work of 

 1910 was that the Toxopneustes $ X Hipponoe cT hybrids lived better in 

 sea-water of reduced alkalinity than in the normal sea-water. 



