I recently photographed Lesser cylinder-anemones, Synarachnactis lloydii at the Zeelandbrug, because they looked odd with short, withered tentacles and a few had even abandoned their tubes. In some of those photos I had a bycatch: hundreds of the horseshoe worm Phoronis psammophila! I had often looked for them without success, likely swimming right past them. During that dive at the Zeelandbrug, I had noticed a sort of downy layer on the seabed; it turned out to be tens of thousands of these horseshoe worms.
On the next dive I took a closer look, found and photographed them and collected a few specimens for study and photography. See HERE for the results. I suspect they are significant competitors for food with the Lesser cylinder-anemones.
