The horned helmet usually attaches its egg masses to clumps of Halimeda algae that are held to the bottom by their holdfasts. Occasionally we have seen egg masses attached to pieces of dead coral rubble in the sand.
Looking carefully at the egg capsules in the upper part of the photo, you can see the individual eggs as multiple little dark spots within each one. It would appear that a helmet produces many thousands of eggs in each mass. Obviously most of these will not survive to adulthood or the atoll's lagoon would have long ago been filled up with helmet shells.
Created 10 January 2011