The coronate scyphomedusae include some of the most stunning of all the jellies.  Within Monterey Bay this group is nearly entirely found only in deep midwater habitats, so you are not likely to see one at the surface.   Among the coronates, Periphylla periphylla is the only species known to be holoplanktonic without any kind of sessile polyp stage.  It also lacks the ephyra stage and does not produce planula larvae like other scyphozoans.  Like other coronates, Periphylla has a groove in the exumbrella (the coronal groove) that probably provides some flexibility to the relatively stiff bell.   The bell may reach up to 20 cm in height, has 16 lappets around the margin, and is topped off by a conical apical tip.  The tentacles are stiff and 12 in number, and often held in an upward position.  They form groups of three that alternate with the 4 rhopalia.  Through the transparent bell is seen a strikingly beautiful deep reddish-brown stomach area.  Presumably the brilliant pigmentation in this and other deep-water jellies masks the light produced by ingested bioluminescent prey.  Periphylla is a vertical migrator, rising to shallower depths at night to feed on copepods and other crustaceans.  It is found throughout the worlds oceans, typically below 900 meters in Monterey Bay and as deep as 7000 meters in other areas, but potentially at the surface in higher latitudes.  Periphylla may reach much larger sizes in Antarctic waters compared to temperate latitude populations.  This species may be the most abundant, widely distributed deep-water scyphozoan, and is commonly collected in midwater trawls by scientists.

All photographs © David Wrobel and may not be used or copied without permission!