Illustrated here is the hydromedusan Cigar Jelly (Olindias phosphorica), a cnidarian, class Hydrozoa. Hydromedusae may range in size from a few millimetres to several centimetres in diameter when fully grown. They vary in consistency from soft and gelatinous to firm and gristle-like. Although the jelly is usually transparent, the manubrium, tentacles, tentacle bulbs and gonads of living medusae may be delicately and variously coloured, as exemplified here. Certain deep-sea forms are heavily pigmented. In addition bioluminescence occurs in some species, such as Aequorea spp. Swimming is accomplished by rhythmic pulsations of the umbrella, resulting from the opposing forces of muscular contraction and mesogleal elasticity. A number of species are known to undergo vertical migrations daily.

This Cigar Jelly has a bell about 4-5 cm in diameter and the tentacles of which are retracted during the day (see above left). At night these appendages are fully extended, often up to lengths of ten metres or so, for feeding upon small fish and zooplankton (see above right). Their tips are jigged as a form of lure to attract their plankton prey. This species is commonly found in nearshore marine waters, over the continental shelf. This particular individual was photographed off Lizard Island on the Great Barrier Reef.