AN HERMAPHRODITE ARBACIA

¹ From the Biological Laboratory, Princeton University, and the Marine Biological Laboratory, Woods Hole, Mass.

1. A rare case of perfect functional hermaphroditism in the sea urchin Arbacia punctulata is described. There were four red gonads predominantly female and one white gonad predominantly male; there were a few tubules of the opposite sex in all the gonads.

2. Fertilization occurred as soon as the sexual products were liberated in sea water.

3. The development of the self-fertilized eggs was absolutely normal, in time and morphology, and normal plutei were raised, nine days old.

4. There occurred about 1 per cent of giant eggs; these were twice the normal volume, and they also developed normally.

5. Both the eggs and the sperm also functioned perfectly normally with other normal males and females.