Yes, they do. Hydrostatic skeletons aren't bone, but fluid-filled cavities surrounded by muscles.
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Sharks have a cartilaginous skeleton.
yes
No bones, but they do have a hydrostatic skeleton.
slug worm jellyfish
They have a type of skeleton called a hydrostatic skeleton. This type of skeleton is a fluid filled sac which is surrounded by muscles.
Some animals have that a hydrostatic skeleton include jellyfish and earthworms. Additional examples include sea urchins and starfish. As a result of their flexibility, hydrostatic skeletons are particularly useful for locomotion.
A hydrostatic skeleton is found in many ectothermic, soft bodied animals that have a coelom surrounded by muscles. These include jellyfish, earth worms, sea urchins, and star fish.
Jellyfish have what is called a hydrostatic skeletal system. This means that it is not actually hard. It is more similar to a balloon filled with water. It allows the jellyfish to move in the water as well as allowing its body shape to change with the movement of the ocean and with the jellyfish's own movement without causing injury to the animal. This kind of flexibility is required for such a delicate animal to survive. It's really an amazing system. When the jellyfish contracts the muscles surrounding the pouch (its hydrostatic skeleton) it causes movement. Jellyfish are not the only animals with this kind of skeleton. For example, earthworms also have a hydrostatic skeleton. That is why they can be long and skinny one moment, and short and fat the next.
echinoderms (starfish, sea urchins), coelenterates (jellyfish), annelids (earthworms), nematodes, and other invertebrates (snails).
A hydrostatic skeleton is a type of skeleton many animals in the animal kingdom have.
The hydrostatic skeleton of a jellyfish is made up of various muscles that act as pumps which increase fluid pressure in the tubes that the skeleton is made of. As the pressure goes up, the pseudo skeleton hardens until it becomes rigid from fluid pressure.
a hydrostatic skeleton
worm
Animals that have a hydro-static skeleton have a fluid filled body cavity and a muscular body wall. This skeleton has no hard parts but a animal can squeeze the fluid from one area of the body to another under pressure to give him support.