A jellyfish that carries its tentacles above the bell margin and hunts other jellies.
A small hydromedusa with a firm, solid-looking bell, a scalloped or lobed margin, and one character that settles the group: the tentacles leave the bell some way above the margin rather than at the rim, so they trail stiffly back over the top of the animal instead of hanging beneath it. There are no radial canals, and the stomach is a broad flat pouch rather than a hanging manubrium. Most are under 3 cm. Other small hydromedusae carry their tentacles at the rim, which is the quickest way to separate them. Identification is at the order or, in a few cases, the genus: Aegina with four thick tentacles, Solmundella with two, Solmaris with many and a simple margin, Cunina and Pegantha with lobed margins and more complex stomach pouches.
They eat other gelatinous animals. A narcomedusa swims with its tentacles held forward like a trawl and takes siphonophores, ctenophores and other medusae, frequently swallowing prey larger than itself, and a bell distended around something half-digested is a common sight. Several Cunina species go further: the larva develops on or inside the manubrium of another medusa, feeding on it, before leaving to complete its growth in open water.
They are also one of the more reliable places to find a hyperiid amphipod, which rides on the bell or sits in the stomach pouch. A narcomedusa with a rider, or with a recognisable meal inside it, is a better record than the medusa alone.
Ratings are per location: 1 means found on most dives that look for it, 5 means a handful of records. Where enough dives have been logged the figure is calculated from them; otherwise it is an editorial estimate, and says so. We publish habitat and destination, not the dive site.
