Once we found a whole acre of sea-bed covered with a great swarm of sea-hares, their royal-purple, egg-shaped bodies with a neat pleated frill along the edge and two strange protuberances on the head looking, in fact, extraordinarily like the long ears of a hare. There were hundreds of them gliding over the rocks and across the sand, all heading towards the south of the island. They did not touch each other or display any interest in each other, so I assumed it was not a mating gathering, but some form of migration.
