Mostly limpets, I found when I got home. But these limpets seemed different:
The shells were decorated with a grainy icing, and this one seemed to have a crown.
Another encrusted shell, this one with hair.
And this one has tiny, calcified spirals.
On another, barely visible, even under the maginfying lens, I could see movement at the mouth of the spiral. I got out the microscope:
The tube end.
This fan pulled in, then spread out rhytmically, but much slower that a barnacle would. The lower orange oval seems to be the operculum, or trap door; it was closed on a couple of other tubes.
This is one of the dwarf calcareous tubeworms, Pileolaria sp. They are polychaetes, like my big 12-inch Nereis, but the tubes only grow to about 6 mm across. This one was probably about 1 mm. They build their tubes of calcium carbonate, like the shells of snails and clams; other tubeworms make soft tubes or encase themselves in mucus and sand. I have seen these tiny macaroni coils on rocks and shells many times, but this is the first live one I've observed.
An odd fact from the Marine Life Encyclopedia:
"... these worms breed their young in their trap doors! Once fertilization has occurred, the trap doors serve as brood chambers for the developing embryos. Depending on the species, these calicfied trap doors may be in the form of an open cup or helmet-shaped chamber that can be used for more than one brood."The grainy crust over the top of the limpet seems to be a bryozoan, too small and indistinct to identify without disturbing the limpets.
Like a mound of smashed glass goblets. The blue patches are reflections of the microscope's lighting system.
There were other critters, too. More on these, later.