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Chondrophoran medusae are very small, 3 mm tall by 2 mm wide, and therefore would be quite easy to miss. They also seem to be rare; they weren’t reported in the Atlantic until 1980 (Larson 1980). The chondrophorans are analogous to a floating, single hydranth of an athecate hydroid in structure and development as well as in some behavioral traits. For example, they exhibit whole‐organism contractile behavior known as concert behavior.

Velella medusae are brown in color due to high concentrations of zooxanthellae in the subumbrella. The presence of zooxanthellae and the fact that they were first collected in situ by blue‐water divers strongly suggest an epipelagic life habit for the medusa stage of Velella.

The medusa itself has sensory papillae on the exumbrella, four marginal bulbs, two with pairs of tentacles, one of each pair short, and a conical manubrium. The bell is cylindrical in shape with a flat apex (Larson 1980).