Beachcombing on Isla Espiritu Santo near La Paz:

This white sand beach was the stunning backdrop for a natural display of a great variety of shells, gems of the sea. In addition to conch, cone, clam, scallop, sea urchin, sea biscuit and coral, some of our guests discovered a small number of Paper Nautilus (inset) shells. Aptly named, the shells are so fragile that the slight pressure from a pair of fingers will crush it.

These delicate shells are made by the pelagic octopus Argonauta. The female octopus produces the shell with two of her arms. After making the shell, she gently deposits fertilized eggs into it and then often rests in the opening until the eggs hatch. The young octopuses float away, as does the spent female. The empty shell floats on the waves until it comes to rest on the beach. Here the fragile shell sat nestled on the sand waiting for us.