Moon Jellies, from the Monterey Bay Aquarium:
“These alien-looking creatures are named for their translucent, moonlike circular bells. Instead of long, trailing tentacles, moon jellies have a short, fine fringe (cilia) that sweeps food toward the mucous layer on the edges of the bells. Prey is stored in pouches until the oral arms pick it up and begin to digest it.”
Nikon D70, 18-55 f3.5-f5.6, 18mm, f5.6, 1/4 sec, ISO 400. 2-25-10, 3:17:19 PM PDT.