Barnacled

Went down to the shore at low tide to collect some mussels for a chowder.
The mussels have dwindled but the barnacles have multiplied, cemented in their millions head down on the rocks. When submerged again they'll open up their shuttered backsides and wave their legs in the water to capture the plankton that forms their diet.

Charles Darwin spent 8 years studying these marine crustacea, from great goose barnacles to microscopic parasitic ones. Working from home, his children were so accustomed to see him peering into his microscope day after day, dissecting, making drawings, taking notes and receiving soggy parcels, that one of his sons, given a tour of a school friend's house - the nursery, the parlour, the library - finally asked "So where does your father do his barnacles?"