Let us help you identify that mysterious object you’ve found.
Currently in CHALLENGE mode: If you've got something obscure knocking about, post a picture, and let's see how we do. Please prefix such posts with "CHALLENGE:" so we know we've got a fighting chance.
What are these dotted ball shaped things I circled in yellow in the image?
I thought they may be sea urchin skeletons. Though the things in the image may be too many and too large?
They are in a mural in Brighton, England. The subject is "Protecting Costa Rican Wildlife", so I guess they are of some native species there.
Urchin shells
To be more specific on the terminology they are sea urchin tests: https://en.wikipedia.org/wiki/Test_(biology)
Yes, missing the spines.
Yes they look like sea urchin. However, the live ones look like the black shapes.
Not all urchins look like that, there's a lot of different types
Fun fact: we call them "sea hedgehogs" in Hungarian.
Jellyfish maybe?