CEDO INTERCULTURAL CENTER FOR THE STUDY OF DESERTS AND OCEANS
is a very amazing group to have down here. They don't mind me sending pictures of things I find on the beach that aren't in my books, and asking them "What is this?"
This was the latest. We had never seen one of these. So I sent the picture off to CEDO and their response is below.
We are pretty sure you took a photo of a cannonball jelly fish. Here is a scanned copy of the article the CEDO published on these critters back in 1994: