Polyorchis penicillatus (Eschscholtz, 1829)
Common name(s): Red-eye jellyfish, bell medusa, bell-shaped jellyfish
|Synonyms: Polyorchis penicellata|
|Polyorchis penicillatus from Rosario Bay. About 3 cm long.|
|(Photo by: Dave Cowles, June 2006)|
How to Distinguish from Similar Species: 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 subumbrellar space. Polyorchis haplus does not have lateral diverticula on the radial canals.
Geographical Range: Aleutian Islands, Alaska to Sea of Cortez, Mexico
Habitat: A coastal species (nearshore), especially in bays.
Biology/Natural History: This is a
along the west coast. It can often be seen in midwater but more often
swims near the bottom, especially around eelgrass. The jelly eats
amphipods and other small crustaceans which are common on eelgrass,
as well as worms and crustaceans from the bottom and small plankton.
Sexes are separate. The polyp stage of this species is either very
small or unknown, and the medusa may develop directly from a planula larva.
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 nearly
absent in others.
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Johnson and Snook, 1955
Morris et al., 1980
Ricketts et al., 1985
Wrobel and Mills, 1998
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 long, dangling
gonads inside the bell.