They are sea cucumbers. The body of the animal is hidden in the rocks, and what you are looking at is the feeding tentacles. If you look closely at the second picture, you will see that one of them is inserted into the animal's mouth -- they feed by capturing things in the "net" of tentacles, and then "licking their fingers". In fact, they even do it in the same order all the time, and it isn't necessarily going around the circumference. I like sea cucumbers; it's cool to watch them feed, and they add bright spots of color to the dive.