A white cross hydromedusae, Staurophora mertensi, off the coast of New Jersey, USA. This hydromedusa is found from the Arctic to Rhode Island, along the coast. At night it rises to just below the surface. It feeds on other medusae and crustaceans. In the northern part of its range, it is seen spring through late summer. In the southern range, it is normally found spring to early summer. It can reach 12" wide and 2" high.