In scyphozoan jellyfish, the free-swimming medusa form is the dominant stage, with the sessile polyp form found only during larval development.

自由游泳见于各海洋，包括常见沿海岸线漂流盘形动物(甲壳动物)。

In the adult, or medusa stage of a jellyfish, they can reproduce sexually by releasing sperm and eggs into the water, forming a planula.

在海蜇成体或体阶段，它们通过将精于释放到中形成浮浪幼体而进行有性繁殖。