nematocyst

[nem-uh-tuh-sist, ni-mat-uh-]

noun

Zoology.

1. an organ in coelenterates consisting of a minute capsule containing an ejectable thread that causes a sting.

nematocyst

/ nɪˈmætə-, ˈnɛmətəˌsɪst /

noun

1. a structure in coelenterates, such as jellyfish, consisting of a capsule containing a hollow coiled thread that can be everted to sting or paralyse prey and enemies

nematocyst

1. One of the minute capsules in the tentacles of cnidarians, such as jellyfish, hydras, or sea anemones, used for stinging. The capsule is produced by a special cell (called a cnidoblast) and contains a tightly coiled barbed thread that quickly shoots forth if the capsule's lid is disturbed. The thread often contains poison.

Other Word Forms

• nematocystic adjective

Word History and Origins

Origin of nematocyst¹

First recorded in 1870–75; nemato- + -cyst

Example Sentences

Now a team led by Matt Gibson and Ahmet Karabulut of the Stowers Institute for Medical Research in Kansas City, Mo., has used cutting-edge imaging technology to study nematocyst firing in very fine detail.

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The tentacles are carpeted with hundreds of thousands of specialized cells, each harboring a capsule called a nematocyst that can fire a microscopic harpoon at speeds of more than 60 kilometers per hour.

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The lid on Polykrikos’s nematocyst overlays a complicated, three-ringed structure not found in cnidarians that the scientists termed a “nozzle”.

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It contacts prey before the nematocyst and sits atop the nematocyst like the final stage of an Apollo rocket, connected to it by a newly discovered “linker” organelle.

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It does not appear that the nematocyst of Nematodinium actually fires like a Gatling gun, rotating, with only one barrel active at a time.

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