The best time for visiting the reef is at low tide. The tides in the Society Islands differ from those in most parts of the world, by never varying from one day to another throughout the year. At noon and at midnight is the height of the flood, and at six o'clock morning and evening is the lowest of the ebb. Ordinarily the rise is about two feet; periodically twice a year there comes a tidal-wave that breaks over the reef with great violence, and sweeps across the lagoon to the shore.
Frank and Fred sought an explanation of this tidal peculiarity, but were unable to obtain a satisfactory one. A resident of Papéiti said the tides were so certain in their movements that many people were able to tell the time of day very nearly by a glance at the reef.
THE BOTTOM OF THE LAGOON.
To the student of marine life a coral reef is full of interest, and that of Tahiti is one of the finest in the world. Here are some of the curious things that were described by our friends:
"We saw," said Frank, "some enormous starfish with fifteen arms covered with sharp spines of a gray and orange color. These spines were on the top of the arms; the bottom had an array of yellow feelers like fingers, with suckers at the ends. The boatmen cautioned us not to touch these creatures, but their caution was not needed, as we all kept our hands at a respectful distance.
