Between the ectoderm and endoderm a gelatinous supporting layer, termed the mesogloea, makes its appearance.
The medusoids have a muscular velum of ectoderm and mesogloea only.
The mesogloea is greatly developed in them and they are often of very tough consistency.
The mesogloea of the medusa is largely developed and of great thickness in the umbrella.
The corallum shaded with dots, the mesogloea represented by a thick line.