Cnidarians, like jellyfish, corals, and sea anemones, are known for their stinging cells called nematocysts. However, these stinging cells are primarily used for defense and capturing prey, not for locomotion.

Cnidarians use a variety of methods for movement, depending on the species:

1. Jet Propulsion: Jellyfish use a pulsating bell (the umbrella-shaped structure) to propel themselves through the water. They contract the bell, forcing water out and creating a jet of water that propels them forward.

2. Muscular Contractions: Some cnidarians, like sea anemones, use muscular contractions to move slowly across the seabed. They have a muscular foot, known as a pedal disc, which they use to anchor themselves and then contract muscles to move.

3. Water Currents: Some cnidarians, like corals, are sessile (attached to a surface) and rely on water currents to bring them food and oxygen. They can also move very slowly by shifting their positions slightly.

4. Tentacles: Some cnidarians use their tentacles for limited movement. They can use their tentacles to anchor themselves to a surface or to pull themselves along.

Stinging cells (nematocysts) play no direct role in locomotion for cnidarians. They are specialized structures located in the tentacles and used for:

* Defense: To deter predators and protect themselves.

* Prey Capture: To paralyze or subdue prey.

Therefore, while nematocysts are a defining characteristic of cnidarians, their primary function is not locomotion.