Yeah, they look like by-the-wind-sailors (sorry, that's the name I know them by, that and Vellela). The web-like membrane on their backs can be raised like a sail, to catch the wind and move them about, or in this case strand them on the beach, poor things. They are actually colonies of micro-jellyfish, and have tiny stinger tentacles on the underside with which they catch plankton and such tiny stuff. Don't pick them up, some people are allergic, and while most human skin is resistant to their tiny stinging cells, getting them near your eyes and mouth may be unwise. We used to find them washed up on the beaches in the West of Ireland.