Noun
mesoglea (countable and uncountable, plural mesogleas)
A gelatinous material found between the epithelial cellular layers of jellyfish and coelenterates
However, a ring of muscle fibres is present within the mesoglea around the rim of the dome, and the jellyfish swims by alternately contracting and relaxing these muscles. Source: Internet
In 1881, it was proposed that Ctenophora and Bilateria were more closely related to each other, since they shared features that Cnidaria lack, for example muscles in the middle layer ( mesoglea in Ctenophora, mesoderm in Bilateria). Source: Internet
They also secrete the jelly-like mesoglea that separates the layers. Source: Internet