As a SCUBA diver, I’ve had a lot of interaction with jellyfish and their “cousins”. They belong to the phylum (large group) “Cnidaria”. All in this group have specialized stinging cells. If you have ever come into contact with a “Cnidarian” you know about the stinging cells.
The Phylum “Cnidaria” contains the jellyfish and their cousins, the corals and anemones.
The stinging cells of the “Cnidaria” are called “nematocysts”. This is a coiled, venomous, thread-like harpoon that fires when touched. The nematocysts are contained on long tentacles that, in the case of the jellyfish, hang down from a “bell”. In the case of the corals and anemones, the animal is attached to the ocean floor and the tentacles float upward. When a small fish, or a SCUBA diver touches the tentacles, the harpoons fire a…