EFFECTS OF EXPOSING GERM-CELLS TO RAYS OF RADIUM 239 



In some of the experiments the ovary (egg-cell) only was exposed, 

 in others the anthers (sperm-cell) only; in a third set both egg- and 

 sperm-cells were treated. In each of these three cases the exposure 

 preceded pollination and was discontinued after pollination. In 

 still other cases exposure of the ovary was made after pollination 

 with unexposed pollen, and again exposure of the ovary was made 

 while it was maturing and the exposure continued after pollination 

 and until fertilization was presumed to have taken place, or in some 



Fig. 6S. Otiagra biennis. Functionally Asymmetrical Rosette. Close Pollina- 

 tion followed an exposure of both Ovary and Pollen to Rays from a Radium-coated 

 Rod of 10,000 Activity for four Days. Cf. figures 67, 69, and 70. 



