How are a cnidarian polyp and a medusa different?

Cnidarians exhibit two primary body forms, the polyp and the medusa, which differ significantly in structure, mobility, and life cycle role.12

Structural and Behavioral Differences

• Polyp: This form is typically cylindrical and sessile, meaning it is attached to a firm substratum at its lower end. Its mouth and surrounding tentacles face upward. Polyps can be solitary, such as sea anemones, or colonial, such as corals.312
• Medusa: Commonly known as a jellyfish, the medusa is bell- or umbrella-shaped and free-swimming. Its mouth is located at the tip of a stalklike manubrium hanging downward from the center, with tentacles typically suspended from the bell's margin.31

Life Cycle Roles

In species that alternate between both forms, the polyp is generally considered the juvenile stage, while the medusa is the adult stage. Polyps typically reproduce asexually to produce medusae, whereas medusae are responsible for sexual reproduction, releasing gametes into the water. Notably, members of the class Anthozoa exist only as polyps and lack a medusa stage entirely.142