Graphic: An Encyclopaedia of New Zealand 1966.


This information was published in 1966 in An Encyclopaedia of New Zealand, edited by A. H. McLintock. It has not been corrected and will not be updated.

Up-to-date information can be found elsewhere in Te Ara.



This beautiful bright-blue member of the jelly-fish family is an immigrant from more tropical waters and is often washed up in large numbers on our northern west coast beaches. Unlike the common jellyfish, it is not a single individual, but a colony of organisms up to 6 in. long, the whole group floating by means of an air-filled bladder on the upper surface. From the under surface hang a number of long tentacles armed with powerful stinging cells which can paralyse quite large fish, and can also give human beings a very painful sting. Above the water surface projects a diagonally placed crest, very like the sail of a yacht and serving the same purpose. The sail may be either left- or right-handed or in yachtsman's terminology the man-of-war may be on either the “starboard or the port tack”. It is believed that the direction of the sail is related to the prevailing wind; thus it will usually be in opposite directions north and south of the equator. A similar but smaller species is the “By-the-wind-sailor” (Velella) which also has a raft and sail.

by Richard Morrison Cassie, M.SC.(N.Z.), D.SC.(AUCK.), Senior Lecturer in Zoology, University of Auckland.

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