THE FORMATION OF GIANT POLAR BODIES IN CENTRIFUGED EGGS OF ILYANASSA

¹ From the Biological Laboratory, Princeton University

1. If the second maturation spindle of the egg of Ilyanassa is displaced from the animal pole by centrifugal force, a giant polar body may be formed. If the sperm nucleus is included in the giant polar body the latter, instead of the egg proper, may develop.

2. The close of the maturation division in centrifuged and elongated eggs is attended by the production of clusters of cytoplasmic lobes around the region where the achromatic figure lay. These lobes are distinct from the normal polar lobe.

3. In strongly centrifuged eggs five zones of substances are separated. These include two clear zones separated by a band of fine, colorless granules.