The Latin name of this species, cruxmelitensis, refers to the arrangement of the white nematocyst capsules (stinging organs) in the distinctive pattern of a Maltese Cross.

It characteristically appears 'stalkless', although in fact it attaches to its location via a short stalk that terminates in a broad basal disc.

It appears to have the unusual capacity to hold itself very rigidly in this posture, even when subjected to agitation caused by tidal flow.

The septa walls contain the gonads, which are thick, linear and Y-shaped, joining at the base of the bell and then extending outwards to the arms.

[1] Gametes are produced from the gonads, which are located on the sepal walls, and shed into the surrounding water where fertilisation takes place.