Those weird marine organisms were found by me last summer in a shallow sea in Chalkidiki of northern Greece. I have met them before. The one is a branched reddish-brown sessile organism which resembles an algae, a sponge, I don't know, and I have found it many other times covering rocks. It attaches itself with a holdfast, branches a lot from the base and all over, with tiny structures at its tops. It is hard and difficult to cut. Some, like the one piece of the three of the photo, bear some filaments in the middle. Have they something to do with reproduction?
As for the second, I remember finding it one other time, and much smaller. The current one was attached firmly on the inside of a crack of a rock. It has a smooth dark leathery exterior with no slime like a mollusc or worm, and bears scattered warts. The underside is concave and probably functions as a big sucker. I cut a small part of the organism, but nothing came out. I didn't open it, though. Both of them had a marine smell to them. What could they be? … 014009.jpg … 014010.jpg … 014011.jpg
I don't believe they are mediterranean endemics, they were found in very shallow waters, so they must be common and widespread. Thank you very much in advance.

And another question. Are there any brachiopods in the costal zone anywhere in Greece, or at least generally in north-eastern mediterranean?

the first photo is too out of focus to be sure, but it looks like a mixture of algae, corraline algae and possible bryozoans all encrusting on the stem of another larger marine plant or algae.