In the year 1901 New Zealand annexed a number of islands of the Pacific. Among them were the Cook Islands and the Island of Rarotonga, from where, according to Maori belief, New Zealand got its first Polynesian settlers. The Cook Islands are of volcanic origin but thereupon we leave the volcanic belt and get into the midst of the coral islands.
These are formed by little marine organisms, the Anthozoa or “flower-animals” which die but whose assembled skeletons are responsible for the thousands of reefs and islets which dot this part of the Pacific Ocean. These polyps are fussy creatures. They can only live in fresh salt water of a certain temperature. A single frost will kill them. They cannot descend lower than about 120 feet. Whenever we find coral deposits lower than that we know that the bottom of the ocean must have sunk from its original level. But they have been building their little islands for millions of years and their work is more enduring than that of the best masons. As they depend upon a constant supply of water-in-motion, the polyps who live in the center of the edifice are apt to die off first The edges then continue to grow and finally they form a so-called atoll, an island consisting of a narrow ring of solid material with a circular lagoon in the center. There is usually a single entrance to such a lagoon and it is always away from the prevailing winds as the waves on the other side provide the polyps with a more abundant food supply and therefore make them grow faster.
A number of such atolls which grow coconuts and produce copra now belong to New Zealand and the German share of Samoa was given to the dominion as a mandate in recognition of the excellent services of the New Zealand troops during the Great War. What they are going to do with it I do not know.