Just one note concerning Janthina. They are supposed to live in rather large numbers in Mare Sargassum, an area in the Atlantic Ocean which has little movement of its waters, allowing surface plants and animals a place to live from which they will not be torn by air and water currents. I imagine there has been some work published on the inhabitants of this area. It would be interesting to know what sea- weeds live there and what mollusks live on the weeds. Art