Clam Worms
Clam worms reproduce sexually. Fertilization is external and the sexes are separate. They do not have permanent gonads. During the reproductive season, sperm and eggs fill the body cavity. Clam worms are nautical worms and when they transform into a reproductive form called an epitoke, they swim to the surface of the ocean and swarm. They release their sperm and egg into the water. This reproductive swarming depends on the temperature, salinity of the water, and the lunar period.