Sorry but I can't get in touch with the person who gave me that photo for a while now, I really have the feeling those things are c.a. 10cm long when I look at that picture, but that's only my feel about it.
Methinks they are sea squirts - one of the life forms grouped under the subphylum Tunicata ('tunicates').
Tunicates come a wide range of shapes and colours. They can be relatively solitary 'sacs', with an obvious pair of openings (siphons). But many are more colonial, like yours (if I am right). They can anchored or free. Here's a grey colonial one, though rather more shapeless than yours - http://www.bbc.co.uk/news/uk-wales-north-west-wales-15671705.
Yes, thanks indeed, I have little doubt now that those are some sort of colonial tunicates.
The genus Didemnum got my attention as many species whithin it seem to show a similarly dotted "outer skin".
Didemnum molle in particular shows striking resemblance regarding this "outer skin", but I am bothered by the fact that no sort of opening can be seen anywhere on this photo.
Maybe someone can tell whether those could be juvenile (again, just guessing here) or if I am taking a wrong road.
Thanks a lot for your answer!
No - I don't think they're juvenile.
Didemnum molle is a good condidate.
I suspect with yours:
- as in this photo, the siphons are sparse, or shall we say not very prominent -
- because yours is out of water, the siphons are closed.