Transparent jellyfish on display in an aquarium.After
fertilization and initial growth, a larval form, called
a planula, develops from the egg. The planula larva is
small, and is covered with cilia. You could think of it
as looking like a tiny hairy football. The planula larva
settles onto a firm surface, and changes into a polyp.
The polyp resembles a tiny sea anemone— cup-shaped
with tentacles surrounding a single opening. Once the
polyp begins reproducing asexually by budding, it's called
a segmenting polyp, or a scyphistoma. New scyphistomae
may be produced by budding or new, immature jellies called
ephyra may be formed. These young jellies swim off and
grow up into adults. Like all other cnidarians, jellyfish
have stinging cells called cnidocytes which contains the
stinging nematocysts on their tentacles.
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