After some more detective work

I couldn't leave it alone and kept digging through internet about the gelatinous balls and mysterious snails I saw this summer. 

I learnt that gelatinous balls belong to bristle worms or Polychaete or mnogoščetinci, they are their eggs. Some are attached at the end of bristle worm tunnel like this one.

I found almost exactly the same photos as these below and these eggs are supposed to belong to Lugworm or Sandworm (peščeni črv or Arenicola marina). While the photos from Assateague island (on East coast of USA) look almost identical to mine, sandworms typically live in shallow water and could be seen on the beach at low tide. As I remember, mine were't that shallow, but I will surely measure the depth next time. So I'm a tiny bit sceptical about that.

But all of these do belong to bristleworms, of which there are many species, so it is logical that there would be many different kinds of gelatinous balls. If you wish to learn some more about these truely fascinating animals, here is a great article to read: https://www.smithsonianmag.com/science-nature/14-fun-facts-about-marine-bristle-worms-180955773/

For now I'm happy to have figured out where the gelatinous balls generally come from.

There was also another mystery that was bugging me. It started with these two photos already last year, from which I concluded that this creature must be a mollusc. At the time it seemed to me that it was as big as my fist, but when searching for a clue what it might be, I couldn't find anything that would be that big. I was considering it being a limpet (strešica), but they are normally much smaller, or abalone (petrovo uho), but those are also not very big and not so symmetrical. So the mystery remained unsolved.

Sorry for this unsharp photo, but it is the only one I have of the whole animal.

This year I came across another one of these - again on very rugged and exposed shore. It was also overgrown with barnacles (morskimi želodki) and I found it close to the water line, as the one last year.

Once at home I decided I have figure this one out. Unfortunately I again didn't measure it, but again it appeared quite big to me. After much digging through internet I came to only plausible conclusion - it must be a Limpet (morska latvica), probably a common limpet or Patella vulgata. It is the only molusc of this shape that lives in such places and that has small tentacles around the fleshy body, but the real telltale were the patterns that it left on the rock on top right side of the photo, where it was scraping the algae off the rocks. Luckily I came across one photo of these marks, after reading through loads of different articles about limpets. But I again learnt lots of interesting facts, for example that limpets have almost 2000 teeth that are made of the toughest naturally made material, comparable to carbon fibre. They attach to the rocks not by suction, as was thought for long time, but with the special glue, it is still not clear how they can activate and deactivate it as quickly as they do. They wander around the rocks for feeding, but they return to their chosen spot on the rock to rest and with time they make a dent in the rock. Most sources state that they are 6 to 8cm long, so the ones I saw were either really big or my eyes deceived me and I only thought they were the size of my fist. Next time I see one of these grandmothers of limpets, I will surely measure it.