Notes on jellyfish and Hydras

1. Class ScyphozoaClass Scyphozoa (Bell Shaped animals)(Bell Shaped animals)
- The Jellyfishes- The Jellyfishes““Scyph”Scyph”
means bellmeans bell
and refers toand refers to
the jellyfish’sthe jellyfish’s
bell-shapedbell-shaped
animalanimal
(body).(body).

2. Class: ScyphozoaClass: Scyphozoa
• The largest jellyfish has a bell that canThe largest jellyfish has a bell that can
measure up to 13 feet across. The Lion’smeasure up to 13 feet across. The Lion’s
Mane Jellyfish has tentacles that mayMane Jellyfish has tentacles that may
extend as many as 75 feet below the bell.extend as many as 75 feet below the bell.

3. The jellyfish are
characterized by a body
that faces up and its
mouth and tentacles face
downward.
This body form is called
Medusa
They are free swimming
and move by opening and
contracting the bell.

4. Class Hydrozoa – Hydras and theClass Hydrozoa – Hydras and the
Portuguese Man of WarPortuguese Man of War
These Cnidarians have specialized cells in theirThese Cnidarians have specialized cells in their
mesoglea layer that distinguish them from othermesoglea layer that distinguish them from other
Cnidarians.Cnidarians.

5. Hydras look much likeHydras look much like
anemones and live inanemones and live in
freshwater.freshwater.
The Portuguese Man-of-War,The Portuguese Man-of-War,
however is quite unique. It ishowever is quite unique. It is
often mistakenly called aoften mistakenly called a
jellyfish but it isn’t one. It isjellyfish but it isn’t one. It is
actually a colony of polyps.actually a colony of polyps.

6. This Portuguese Man-of-War was carried up onto the beach by heavyThis Portuguese Man-of-War was carried up onto the beach by heavy
winds. It is not uncommon during such times to see thousands of themwinds. It is not uncommon during such times to see thousands of them
stranded on the beach. They can still sting and should be consideredstranded on the beach. They can still sting and should be considered
dangerous.dangerous.
The name comes from the colors of the uniforms worn by PortugueseThe name comes from the colors of the uniforms worn by Portuguese
marines during the 1500’s when they were sailing to South America.marines during the 1500’s when they were sailing to South America.
They wore pink and purple and must have appeared dreadfullyThey wore pink and purple and must have appeared dreadfully
fearsome adorned in such colors!fearsome adorned in such colors!

7. Class Cubozoa – Box JellyfishClass Cubozoa – Box Jellyfish
The bell of this group is cube-shaped. TheThe bell of this group is cube-shaped. The
venom from the Box Jellyfish is so potent that itvenom from the Box Jellyfish is so potent that it
is considered to be the second most venomousis considered to be the second most venomous
animal in the world.animal in the world.

8. The box jellyfishThe box jellyfish
inhabits the Greatinhabits the Great
Barrier Reef off theBarrier Reef off the
east coast of Australia.east coast of Australia.
Lifeguards protect themselves from the box jellyfish’ sting byLifeguards protect themselves from the box jellyfish’ sting by
wearing two pairs of panty hose. One is put on over their bathingwearing two pairs of panty hose. One is put on over their bathing
suit and the second is slipped on over their head. A hole is cut insuit and the second is slipped on over their head. A hole is cut in
the crotch for the lifeguard’s head to stick through and his or herthe crotch for the lifeguard’s head to stick through and his or her
arms go into the legs. The feet are cut off of the hose and glovesarms go into the legs. The feet are cut off of the hose and gloves
are worn. The reason it is effective is that the box jelly’s stingingare worn. The reason it is effective is that the box jelly’s stinging
threads are shorter than the diameter of the panty hose fibers.threads are shorter than the diameter of the panty hose fibers.
Even if the cnidocytes fire and the stinging threads are released,Even if the cnidocytes fire and the stinging threads are released,
they cannot penetrate the lifeguard’s skin to inject their venom.they cannot penetrate the lifeguard’s skin to inject their venom.