Identify this round, slimy, creature?

[beckywaller108]

Recently me and my husband went to the Bahamas and brought back some large conk shells he found in the ocean. I'm guessing it had some hitch hikers on it and I am just curious to know what they are and if they are safe to be in my tank. In the first pick is the slimy, jelly looking thing, about the size of my pinky nail. Top is white and looks like lace on the edges but its under belly is clear and you can see its internals (as shown in pic). It recently started randomly moving all over the tank and I would see it in a different spot every day. I never actually saw it moving, I would just notice it in different spots. Well, for the last 3 days it has been at the top of the tank completely out of the water (as shown in pic). I just don't know if I need to remove it since its there or put it back in the water or leave it be? The other pic is of a flowery looking thing hiding on the inside of the conk shell. If a fish comes close it will close up then open back up. Just curious as to what they are? Thanks!
***FYI, the string looking thing in the first 2 pics is just something on the glass, its not attached to the round creature thingy even though it looks like it is***

 

[badbreath]

Looks like a flatworm to me... I'm interested to learn more for the experts.

 

[smtank]

Limpet perhaps.
Sabellid


http://www.lionfishlair.com/hitchhiker/hitchhiker.shtml

 

[beckywaller108]

It does resemble a Limpet, but it doesn't have the 2 antenna looking things at all. It might be a flat worm? I don't know anything about flat worms, but I am thinking when I get home tonight that I am just going to remove it to be on the safe side.

 

[pagojoe]

I think the first one is a Cup-and-Saucer snail. They get lumped in with the limpets, but it's neither a true limpet nor a keyhole limpet.

Cheers,



Don