The star-fish took passage on this train.  He didn’t start at the beginning of the road, but got in at one of the way-stations somewhere off Cape Cod, fell in with some friends going South, and had altogether a pleasant trip of it.  No wearisome stopping-places to feed either engine or passengers; for this train moves by a power that needs no feeding on the way, and the passengers are much in the habit of eating their fellow-travellers by way of frequent luncheons.

In the course of a few weeks, our five-fingered traveller is safely dropped in the Caribbean Sea; and, if you do not know where that sea is, I wish you would take your map of North America and find it, and then you can see the course of the journey, and understand the story better.  This Caribbean Sea is as full of mountains as New Hampshire and Vermont are; but none of them have caps of snow like that which Mount Washington sometimes wears, and some of them are built up in a very odd way, as you will presently see.

Now the star-fish is floating in the warm, soft water among the mountains, turning up first one eye and then another to see the wonders about him, or looking all around, before and behind and both sides at once,—­as you can’t do, if you try ever so hard,—­while his fifth eye is on the lookout for sharks, besides; and he meets with a soft little body, much smaller than himself, and not half so handsomely dressed, who invites him to visit her relatives, who live by millions in this mountain region.  “And come quickly, if you please,” she says, “for I begin to feel as if I must fix myself somewhere; and I should like, if possible, to settle down near my brothers and sisters on the Roncador Bank.”

CHAPTER II.  CORALTOWN ON RONCADOR BANK.

Where is Roncador Bank, and who are the little settlers there?  If you want me to answer this question, you must go back with me, or rather think back with me, over many thousands of years; and, looking into this same Caribbean Sea, we shall find in its south-western part a little hill formed of mud and sand, and reaching not nearly so high as the top of the water.  Not far from it float some little, soft, jelly-like bodies, exactly resembling the one who spoke to the star-fish just now.  They are emigrants looking for a new home.  They seem to take a fancy to this hill, and fix themselves on bits of rock along its base, until, as more and more of them come, they form a circle around it, and the hill stands up in the middle, while far above the whole blue waves are tossing in the sunlight.

[Illustration:  (Conical mound of coral under surface of water.)]