This observation is for the brown things -- a nice group of solitary corals.

They were living on what looks like a piece of rock, but that is actually the outer surface of a thick old valve of a gryphaeid.

I am sure as I can be that the species of the bivalve is Hyotissa mcgintyi. In one of my publications I record that species from the Lesser Antilles for the first time -- prior to that it had never been recorded from the Lesser Antilles; within the West Indies it was know only from the Greater Antilles.

• Hewitt, Susan J. 2010a, Hyotissa mcgintyi (Bivalvia, Gryphaeidae) from two islands in the Leeward Islands, West Indies with notes on the genus, The Festivus, XLII (3): 31–34