How do you like this little circular town seen in the picture?  It is the beginning of Coraltown, just as the landing of the Pilgrims at Plymouth was the beginning of Massachusetts.  Now we will see how it grows.  First of all, notice this curious fact, that each settler, after once choosing a home, never after stirs from that spot; but, from day to day, fastens himself more and more firmly to the rock where he first stuck.  The part of his body touching the rock hardens into stone, and as the months and years go by, the sides of his body, too, turn to stone; and yet he is still alive, eating all the time with a little mouth at his top, taking in the sea-water without a strainer, and getting consequently tiny bits of lime in it, which, once taken in, go to build up the little body into a sort of limestone castle; just as if one of the knights in armor, of whom we read in old stories, had, instead of putting on his steel corselet and helmet and breastplate, turned his own flesh and bones into armor.  How safe he would be!  So these inhabitants of Coraltown were safe from all the fishes and other fierce devourers of little sea creatures (for who wants to swallow a mail-clad warrior, however small?); and their settlement was undisturbed, and grew from year to year, until it formed a pretty high wall.

[Illustration:  (Individual coral polyp.)]

But, before going any farther, you may like to know that these settlers were all of the polyp family:  fathers and mothers, brothers and sisters, uncles and aunts,—­all were polyps.  And this is the way their families increased:  after the first comers were fairly settled, and pretty thoroughly turned to stone, little buds, looking somewhat like the smallest leaf-buds of the spring-time, began to grow out of their edges.  These were their children, at least one kind of their children; for they had yet another kind also, coming from eggs, and floating off in the water like the first settlers.  These latter we might call the free children or wanderers, while the former could be named the fixed children.  But even the wanderers come back after a short time, and settle beside their parents, as you remember the one who met the star-fish was about to do.

It was not very easy for you or me to think back so many thousand years to the very beginning of Coraltown, nor is it less difficult to realize how many, many years were passing while the little town grew, even as far as I have told you.

The old great-grandfathers and great-grandmothers had died, but they left their stone bodies still standing, as a support and assistance to their descendants who had built above them; and the walls had risen, not like walls of common stone or brick, but all alive and busy building themselves, day after day, and year after year, until now, at the time of the star-fish’s visit, the topmost towers could sometimes catch a gleam of sunlight when the tide was low; and when storms rolled the great waves that way, they would dash against