Biology / Unit 10 Bio 2247 short lesson, about 20 seconds
Four Cnidarian Classes
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The idea
Cnidaria divides into four classes: Anthozoa, polyp-only, including corals; Scyphozoa, true jellyfish; Cubozoa, box jellyfish; and Hydrozoa, a varied group.
In practice
A reef-building coral is an anthozoan colony of polyps; a box jellyfish, a cubozoan, carries venom potent enough to matter medically.
Where people slip
Cubozoan venom potency varies sharply by species — not every box jellyfish poses the danger a few species do.
Your place on the trail
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