"You heard what I said," cried the King, turning to the Prime Minister. "Now go to the General Manager of the Sea Bottom Subway and inform him of my wishes. Also that he must have an express ready to start for the Caribbean Sea tomorrow morning without fail." The Prime Minister bowed respectfully and departed. "Whew!" exclaimed the King, smiling at Mary Louise and his daughter as soon as the three were again alone, "if that Star Fish wasn't a walking encyclopedia! He had everything at his five finger-ends!" "I think I'll take the same train as the little Star Fish," said Mary Louise, "for I've never been to the Caribbean Sea and I think it must be a lovely place." "May I go with Mary Louise?" asked the Mermaid Princess. "Well, I don't see why not," answered her father, after a pause, "only you must get back inside of a fortnight, for your mother will be home by that time." "I must see that my mother-of-pearl trunk is packed," said the Princess. "Come with me, Mary Louise." Then curtseying to the King, they swam up the water stairway to the room of the little mermaid. The next morning found Mary Louise and the Mermaid Princess waiting anxiously at the station for the Iceberg Express. On the platform they recognized among the passengers their little friend, the Star Fish. In a few minutes the express thundered into the station. "Watch your step!" yelled the Polar Bear Porter as he helped Mary Louise and the Princess on board. Then with a rush and a roar the Iceberg Express started on its journey for the Mountains of the Sea! The Wreck Mary Louise and the Mermaid Princess settled themselves back comfortably in their seats and looked about them. The Iceberg Express certainly had every convenience. Of course almost everything was made of ice. But, then, so is most everything in a Pullman car made of steel. There was really very little difference except that the ice was much prettier, it was so clear and white, and the moss cushions that covered the seats were soft and springy. The crystal chandeliers that hung from the ceiling were resplendent with little twinkling lights, and the curtains at the ice-paned windows were made of the thinnest spun ice threads. Even the little drinking cups that were packed in a column, one within the other, at the ice water tank, were made of thin ice. "I don't feel the least bit cold," said Mary Louise, turning with a laugh to her mermaid friend. "Do you?" "Not the least bit," she replied. "It's so different, though, from the first train we were on," continued Mary Louise. "It isn't anything like it really. Why, the first train was only an ordinary iceberg, don't you remember?" "That's because we never went inside," replied the mermaid. "We didn't have the opportunity, the explosion came so soon."