White moon Jellyfish

Positively a jelly fish. An Aurellia Arita (spelling?) aka, white moon jelly fish

It's probably a piece of something like this.. http://www.projectnoah.org/spottings/7100338 which I have no idea which kind of jellyfish it is!

This to me looks like a very dead jellyfish. They can get broken up by boat propellors, or even just the waves. Eventually all the tissue degrades, leaving just the jelly behind. Be careful though, there may still be some stinging cells in there, which will still fire! It looks like all the tissue is gone, but better safe than sorry right? :) I think itm ight be impossible to ID the jellyfish from this! But a cool thing to find on the beach

if it's not a jellyfish, it may be an egg mass of some sort of marine snail?