Sea Nettle

There are 12 valid subspecies of the Sea Nettle (Chrysaora fuscescens), and they are found in abundance in oceans all over the world. The two most known about are Chrysaora quinquecirrha which is found in the Atlantic waters along the East coast of North America, and the second most common (pictured here) is the Chrysaora fuscescens found along the West coast of North America in the north east Pacific.

Their 'bell' gets about 6 - 8 inches wide and their long tentacles enable them to eat much larger prey than most jellyfish species.
The 12 subspecies of Sea Nettle are:
Chrysaora achlyos
Chrysaora chinensis
Chrysaora colorata
Chrysaora fulgida
Chrysaora fuscescens
Chrysaora hysoscella
Chrysaora lactea
Chrysaora melanaster
Chrysaora pacifica
Chrysaora pentastoma
Chrysaora plocamia
Chrysaora quinquecirrha

Aquariums that these jellies can be seen at are:

Hawaii region
Waikiki Aquarium  Honolulu, Hawaii features the Atlantic Sea Nettle (Chrysaora quinquecirrha)

Pacific region
Vancouver Aquarium  Vancouver B.C., Canada
 Monterey Bay Aquarium  Monterey, California features the Black Sea Nettle (?)
Aquarium of the Bay  San Francisco, California features the Pacific Sea Nettle (Chrysaora pacifica)
Aquarium of the Pacific  Long Beach, California
The Birch Aquarium  La Jolla, California