The skeletal System of Cnidaria
Cnidaria is a pretty small phylum and includes about 10,000 species which are mostly marine animals. They contain a mesoglea which works as the endoskeleton. They also have a calcium carbonate or chitin which makes up the exoskeleton. They are both forms of protection for the cnidaria. A special feature is the cindocytes which are specialized cells that are used mainly for capturing prey.
The jelly use their gastrovascular cavity as a skeleton and also use few muscle-like cells for contraction and extension movements. The Gastrovascular cavity is where digestion takes place. Muscles and the gastrovascular cavity for form the exoskeleton. They do not really contain a skeletal system.
|
Mesoglea serves as an internal skeleton, supporting the body. Its elastic properties help restore the shape to the hydra after it is displaced. Mesoglea is non-living, jelly-like substance found between the two tissue's cell layers in the bodies of hydra.
|
Jelly fish do not contain a skeletal system. The purple jelly uses its nerves or nerve net inplace of the not present skeletal system to react at lightening fast speed. The fast reaction allows it to move quickly in the water to catch prey.
|