Nematocysts

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Nematocysts
The name cnidarian derives from the Greek word knidos, meaning “nettle,” referring to the microscopic stinging structures known as nematocysts found on cnidarian tentacles. A cnidarian will stun a prey animal with its nematocysts and then use its tentacles to bring the prey to its mouth to swallow.

Each nematocyst contains a coiled tubule that shoots out like a harpoon with explosive force. There are about 30 kinds of nematocysts that work in different ways to stun prey. The tubules of some nematocysts wrap around prey. The tubules of other nematocysts stick to prey, while other tubules pierce the surface of small animals. The nematocysts of some cnidarians contain poison that can paralyze or kill prey.

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