Mesoglea, also known as ectoplasma, is the clear, inert, jellylike substance that makes up most of the bodies of jellyfish, comb jellies and certain primitive sea creatures in the phylum cnidaria. It acts as the creatures' structural support in water, as they lack bones, cartilage or other more common means of support. Because mesoglea is a gel with such a high water content, these creatures tend to collapse on land.

See also

• Anatomy of corals