H. M. FucHS 267 



TABLE IV. (1.2.2.) 



(I) Water (2) Extract 

 Cross : D/c, C extract Weaker sperm 8 



Stronger sperm < 1 36 



In both parts of the experiment the fertilization percentage was 

 greater in egg-extract than in water. It will be shown later on that 

 this is not only the case for Ciona and Ascidia, but is the same for all 

 the forms tried. 



4. Gross-ferlilization of Ciona in ovary-extract. 



In the following experiment, a comparison was made between the 

 percentage of eggs fertilized (1) in plain sea- water and (2) in ovary- 

 extract, instead of egg-extract. 



Approximately equal amounts of A eggs were placed in (1) 12 cc. 

 water, and (2) 1^ cc. C ovary-extract. After 38 minutes each was 

 fertilized by the addition of one drop of b sperm-suspension. Besides 

 the usual control of unfertilized eggs A, some of the latter were also put 

 into C ovary-extract to guard against the accidental presence in this of 

 sperm from the testis of the same animal'. 



TABLE V. (20.L2,) 



(1) Water (2) Ovaiy-extraet 



Cross:_ Ajh, C extract ... 86 98 



As shown by Table V, the presence of the ovary-extract caused an 

 increase in the percentage of eggs fertilized. 



The next experiment was made on similar lines, but three different 

 concentrations of ovary-extract were used. 



Approximately equal amounts of eggs E were tried out into four 

 dishes containing respectively equal quantities of water and of three 

 different concentrations of D ovary-extract, as is shown in Table VI. 

 After 34 minutes, each was fertilized by the addition of one drop of _/ 

 sperm-suspension. 



TABLE VL (20. L2.) 



15 cc. water S cc. water 



16 cc. water 1 cc, extract 8 cc, extract 16 cc. extract 



Cross: £//, D extract 68 91 92 94 



As is seen from the above Table, this experiment was a confirmation 

 of the last. (The weakest extract was here almost sufficient to raise 

 the percentage of fertilization to the maximum.) 



' This was done in all other experiments in which o\ary-extract was used. 



