Jellyfish at Misawal, Japan

Round, clear jellyfish were found washing on the beach at Misawa, Japan. They were very thick, some had a purplish hue. It was the first time we ever saw jellyfish, so we are unsure what kind. Most did not have any tentacles, some had really short ones. They ranged from a couple inches in diameter to about a foot in diameter. They were very thick, some were about 4-6 inches thick. They were just washing ashore all over the place.