SUMMARY(1)Zoösporogenesis in resistant sporangia is not normally initiated until the resistant sporangia have been dried and/or placed in fresh water or nutrient solution.(2)Thenumberof R. S. zoöspores per resistant sporangium is approximately 4 times as great as the number of female gametes produced in the female gametangium, a structure of approximately the same volume.(3)Thevolumeof R. S. zoöspores at cleavage is approximately one-fourth as great as the volume of female gametes at cleavage.(4)Thevolumeof R. S. zoöspores at cleavage is approximately one-fourth as great as their volume when swarming.