CASTLE: EMBRYOLOGY OF CIONA INTESTINALIS. 209 
TABLE III. — ARTIFICIAL CLOSE FERTILIZATION. 
Cases. 
50 % fertilized 1 
NERA 2 Average for ten cases, 6% — proportion of 
TE 1 ee 
eges fertilized. 
M z | 988 
None “ 4 
Total 10 
TABLE IV. — ARTIFICIAL Cross FERTILIZATION. 
Cases, 
100 % fertilized 4 Average for five cases, 90% = proportion of 
0%“ 1 eggs fertilized. 
Total 5 
As the animals employed in the above experiment had been confined 
in the laboratory for some days, and the production of the sexual elements 
had in consequence considerably diminished, it was thought desirable to 
repeat the experiment on animals freshly collected. This accordingly 
was done with the following equally conclusive results. 
TABLE III. a. — ARTIFICIAL CLOSE FERTILIZATION. 
Cases. 
50% fertilized A 
124% “ 2 d 
TT ES 1 Average for ten cases, 9.4% = proportion of 
5% « 1 eggs fertilized. 
2% [1] 2 
None “ 3 
| Total 10 
TABLE IV.a.— ARTIFICIAL Cross FERTILIZATION. 
100% fertilized in every case! 
