cnidoblast

biology

Written by

The Information Architects of Encyclopaedia Britannica

Last updated

June 24, 2026

Quick Summary

A cnidoblast is a specialized cell found in cnidarians, such as jellyfish and sea anemones. These cells produce microscopic stinging capsules called nematocysts. Each nematocyst contains a coiled, barbed thread that can be explosively discharged when the cnidarian is stimulated. This thread, often containing venom, is used to capture prey or defend against predators. The nematocyst is a unique feature that distinguishes cnidarians from other animal phyla.

Summary created from Britannica articles using AI. AI can make mistakes, so verify using Britannica articles.

3 Britannica Sources

Ask Britannica AI about this topic

Britannica doesn't have a full article on this topic, so we've curated a list of our relevant coverage.

nematocyst
…a special cell called a cnidoblast and contains a coiled, hollow, usually barbed thread, which quickly turns outward (i.e., is everted) from the capsule upon proper stimulation. The purpose of the thread, which often contains poison, is to ward off enemies or to capture prey.
Read More
…a special cell called a cnidoblast and contains a coiled, hollow, usually barbed thread, which quickly turns outward (i.e., is everted) from the capsule upon proper stimulation. The purpose of the thread, which often contains poison, is to ward off enemies or to capture prey.
Read More