Ulmaridae Family of Jellyfish

One Jellyfish of the UImaridae Family can be found in this website:

Pacific Moon Jellyfish, Aurelia labiata. A representative of the Ulmaridae Family of Jellyfish.

The Ulmarid Jellyfish of the Ulmaridae Family, like coral polyps and sea anemones are in the Phylum Cnidaria. This is indicative that they have radial symmetry with their bodies consisting of an inner layer (endoderm) and an outer layer (ectoderm). Both layers are separated by a jelly-like mesoglea.

The Ulmarid Jellyfish of the Ulmaridae Family are in the Class Scyphozoa indicative that they spend the majority of their life in the medusa stage (bell or umbrella shape) form. Their bells can be fairly large, and are often colorful. As Scyphozoans, these jellyfish lack a vellum (shelf-like structure around the inside margin of the bell) and, usually, lack a ring canal (canal lined with gastrodermis that runs around margin of bell). The margins of the bell are often scalloped with lobes or lappets. Tentacles or other sensory organ may be located between these lappets.

The Ulmarid Jellyfish are in the Order Semaeostomeae. They have the classic jellyfish appearance, with long frilly oral arms extending below the center of the bell, and shorter tentacles extending from the margins of the bell. Family members are not easily recognized without looking closely at their anatomy. Keys include simple or branched radial canals and a ring-canal; with or without subgenital pits. Some species of Ulmarid Jellyfish have a bell with a maximum diameter of 40 cm (16 inches), and some have oral arms that can reach 7.0 m (23 feet) in length.

The Ulmarid Jellyfish are generally found in open water. They propel themselves through the water by opening and closing their bell. Their swimming ability is limited, and they are largely at the mercy of ocean currents. Some species in this family are found near the surface, but others are found at depths of at least 1,500 m (4,920 feet). They feed on small crustaceans, ctenophores, mollusks, tunicates, and other jellyfish. In turn they are preyed upon by parasitic crustaceans, fish, sea birds, sea turtles and other jellyfish. They feed by trailing their tentacles and oral arms through the water. When they contact prey, the nematocysts (stinging cells) are triggered, and the envenomation paralyzes the prey. The oral arms then move the prey to the mouth.

The Ulmarid Jellyfish of the Ulmaridae Family are found worldwide, in tropical, temperate, and polar waters. While they are generally a pelagic species, currents can push them into bays and estuaries. This is a small family with forty-one members. Two family members are found in Mexican waters along the Pacific Coast