What role does the mesoglea play in a cnidarian body?

The mesoglea is a largely noncellular, jellylike layer sandwiched between the outer ectoderm and inner endoderm of a cnidarian. It is permeated by a complex network of elastic fibers that provide essential structural support.1

The specific role of the mesoglea varies by body form:

• In medusae: The mesoglea comprises the bulk of the animal and functions as a resilient skeleton. Because it is elastic, it acts as a recovery mechanism; after circular muscles contract to force water out for jet propulsion, the mesoglea’s elasticity allows the body to re-extend, returning the bell to its original shape.1
• In polyps: The mesoglea works in concert with the water-filled coelenteron, which acts as a hydrostatic skeleton, to maintain the animal's form.1

In both forms, the mesoglea provides the necessary structural integrity to support the animal's movement and shape.12