Can you identify Marco Island, FL shells?

[marcoislander]

Please help me identify these shells I found in Marco Island, Florida. The grey and white shell is about 1cm across. In the second attachment, I am trying to identify the two bivalves at the bottom of the photo on the left and right of the spiny jewel box.

[wolfi]

Hi,
for me a little bit difficult to tell...... . Should be family Turbinidae, I think, Genus Astraea. Might be near to Astraea tecta. There are some subspecies with the spines/ribs sometimes more expressed, sometimes less. But it's just a guess......  :-\.
Kind regards: wolf

[dave r]

I would love to help but I can't see any photos, sorry.