Excerpts from Jim Conrad's
from the August 28, 2011 Newsletter
issued from Mayan Beach Garden
Inn 20 kms north of Mahahual, Quintana Roo, México
The other day several gelatinous, transparent discs turned up on the beach. You can see one bove. The first thought is that it's a jellyfish. However, all jellyfish I've seen are shaped like upside-down bowls, with tentacles hanging below. This was flat, and nothing hung below it.
Still, volunteer identifier Bea in Ontario and I figure that it's the remains of a jellyfish, probably the Moon Jellyfish, AURELIA AURITA. That species is common throughout most of the world's oceans, and Marcia says it's common here. Another name found for the species is Saucer Jelly (also Moon Jelly), so that sounds as if others have found such discs as ours.
I think that what we're finding here is dead Moon Jellyfish with their appendages and insides torn away by animals and/or wave action. Maybe what turns up on the beach is just the transparent cap of what once was a much handsomer, upside-down-bowl-shaped creature.