has a bell that is at least as high as it is wide, with many (around
evenly-spaced, unbranched tentacles around the bell margin.
may be contracted to very short (especially when the animal is actively
swimming) or extended to twice the bell length (especially when the
is drifting). As with many hydromedusae,
it has a clearly developed velum.
the tentacles are not grouped into rings. Ocelli
(eyespots) around the bell margin, at the base of the tentacles, are
with red which can be clearly seen. It has 4 unbranched radial
canals which have many (15-25 pairs of) lateral diverticula.
may or may not have several short centripetal
The fingerlike or sausagelike gonads hang down from the subumbrellar
surface, under the radial
canals near the juncture of the stomach with the radial
canals, in 4 groups (photo).
are less than 15 gonads. The bell is transparent with white
but the gonads and some other internal organs may be yellow,
reddish-brown, or purple. The manubrium,
which is long and has 4 short frilly lips, hangs from a rounded
peduncle". Average size is 2-3 cm, and up to 5 (10) cm
Older individuals may have green algae growing on the exumbrella.
Common name(s): Red-eye jellyfish,
bell medusa, bell-shaped
|Polyorchis penicillatus from Rosario
Bay. About 3 cm long.
|(Photo by: Dave Cowles,
How to Distinguish from
Ptychogena lactea and Staurophora mertensi
are similar except
that their bells are much wider than high and their gonads do not hang
down into the
space. Polyorchis haplus does not have
on the radial
Range: Aleutian Islands,
Alaska to Sea of Cortez, Mexico
A coastal species (nearshore),
especially in bays.
This is a
along the west coast. It can often be seen in midwater but
swims near the bottom, especially around eelgrass. The jelly
amphipods and other small crustaceans which are common on
as well as worms and crustaceans from the bottom and small
Sexes are separate. The polyp stage of this species is either
small or unknown, and the medusa may develop directly from a planula
This species is large for a hydromedusa,
and some of the largest hydromedusae
are in this genus. The medusa is common in some years and
absent in others.
and Fairbanks, 1966
and Carlton, 1975
and Snook, 1955
et al., 1980
et al., 1985
and Mills, 1998
General Notes and
Observations: Locations, abundances,
In this closeup view the red spots at the ocelli, the pendant gonads,
the long manubrium
can be clearly seen. The lateral diverticula
are also visible on
several radial canals.
This freely swimming individual has its tentacles extended out farther
than the one above does. Photo by Dave Cowles, July 2008
Another individual, photographed 2012. Note the
gonads inside the bell.
Two individuals dancing in a planktonkreisel. Photo by Dave Cowles, July 2020
for a 1-minute movie of this species swimming in a planktonkreisel,
taken summer 2020. Some individuals are greenish-colored due to algae
adhering to their outer surfaces.
Authors and Editors of Page:
Dave Cowles (2006): Created original page