nematocyst

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.

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.

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

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.

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