[4] Aequoreids include Aequorea victoria, the organism from which the green fluorescent protein gene was isolated.

[6] The colonies are covered with chitinous periderm and can be either prostrate or erect with weak or sympodial branching.

[6] Young hydranths possess hydrothecae with a closing structure called operculum,[6] which consists of several relatively long triangular folds that meet together in the centre when a disturbed polyp contracts.

[6] Comparatively large cylindrical gonothecae are attached to the colony with a thin peduncle.

[6] Mature aequoreid medusae are diverse in shape, from lens-like to conical, and in size.