This bell-shaped hydromedusa
(usually just slightly broader than tall) has about 60-80 unbranched tentacles
which evenly spaced around the margin of the bell.
large rings of nematocycts
all along their length (photo),
and partway back
from the tip of each tentacle
is a larger adhesive knob or pad used for attachment to objects (photo).
to bend at the disk (photo).
bulbs at the base of the tentacles are yellowish-tan (photo)(photo).
The 4 radial
are unbranched and continue all the way to the margin of the
There are no centripetal
canals. Ruffled flaplike orange, red, violet (in
yellow-brown (in males) gonads hang down along the 4 radial
canals and form a clearly visible X shape (see photo above)(photo)(photo).
colored tan and hangs down about to the bell margin, with 4 slightly
lips(photo). The bell
may be clear or light green. (It is unusual for a hydrozoan medusa to
colored but the light green appears to be algae coating the outside of
the bell). Diameter to 2.5 cm.
Gonionemus vertens A. Agassiz,
Common name(s): Clinging jellyfish, Orange-striped jellyfish, Angled
Order Thecata (Leptomedusae)
|Gonionemus vertens, 2 cm
diameter, found on eelgrass in Padilla
Bay, WA. The 4 radial
canals with attached frilly gonads, and the hanging manubrium
|(Photo by: Dave
Cowles, July 2007)
How to Distinguish
from Similar Species:Eperetmus
typus is also deep bell-shaped and has nematocyst
rings on the tentacles
but it has no adhesive pads on the tentacles
and the radial
canals usually have many centripetal
Alaska to southern
California, Kamchatka, northern Japan, Arctic Ocean, N Atlantic to Cape
Cod. On our Pacific coast not common south of Puget Sound but some
have appeared farther south such as near Santa Barbara, CA.
Attached to kelp, eelgrass,
and other substrates (in summer); in at least partly protected waters.
on small crustaceans, especially copepods. The polyp
is seldom seen. The polyps
of this species found in Kamchatka are highly venomous but those along
our coast are not.
Older references list this species as a member of the
and Fairbanks, 1966
and Carlton, 1975
and McConnaughey, 1985
and Mills, 1998
Thomas L., 1985. Cost of Locomotion: Unsteady
Journal of Experimental Biology 119,149-164
Mills, C.E., 1993. Natural mortality
in NE Pacific coastal
hydromedusae: Grazing predation, wound healing and
Bulletin of Marine Science 53(1):
Singla, C.L., 1977. Fine structure of the
adhesive pads of Gonionemus
vertens. Cell Tissue Res. 181(3):395-402
Westfall JA., 1970. The nematocyte complex in
vertens. Z Zellforsch Mikrosk Anat. 110(4):457-470.
General Notes and
abundances, unusual behaviors:
In this view of a swimming individual the kneelike articulation of
several of the tentacles
at the adhesive pad can be seen. Note the tan color on the manubrium,
the gonads, and on the tentacle
This closeup of several tentacles
shows the distinct nematocyst
rings and also the adhesive pads.
In this closeup the velum
can be clearly seen along the margin of the bell. The manubrium
is at top center, a gonad is seen along a radial
canal down through the center of the photo,
and the bell margin with velum
and single row of tentacles
with tan tentacle
bulbs is visible across the bottom third.
In this view of the subumbrella,
the frilly lips of the manubrium
can be seen.
Another view of the subumbrella,
showing the manubrium
and gonads. Photo by Dave Cowles, June 2020
A closeup of the rim of the bell,
showing the tentacles
bulbs. Photo by Dave Cowles, June 2020
Authors and Editors of Page:
Dave Cowles (2007): Created original page
Jonathan Cowles (2007): Updated page with CSS