“These are the hermit crabs,” said one of the mermaids.  “They steal these shells and live in them so no enemies can attack them.”

“Don’t they get lonesome?” asked Trot.

“Perhaps so, my dear.  But they do not seem to mind being lonesome.  They are great cowards, and think if they can but protect their lives there is nothing else to care for.  Unlike the jolly crabs we have just left, the hermits are cross and unsociable.”

“Oh, keep quiet and go away!” said one of the hermit crabs in a grumpy voice.  “No one wants mermaids around here.”  Then every crab withdrew its head into its shell, and our friends saw them no more.

“They’re not very polite,” observed Trot, following the mermaid as Merla swam upward into the middle water.

“I know now why cross people are called ‘crabbed,’” said Cap’n Bill.  “They’ve got dispositions jes’ like these ’ere hermit crabs.”

Presently they came upon a small flock of mackerel, and noticed that the fishes seemed much excited.  When they saw the mermaid, they cried out, “Oh, Merla!  What do you think?  Our Flippity has just gone to glory!”

“When?” asked the mermaid.

“Just now,” one replied.  “We were lying in the water, talking quietly together when a spinning, shining thing came along and our dear Flippity ate it.  Then he went shooting up to the top of the water and gave a flop and—­went to glory!  Isn’t it splendid, Merla?”

“Poor Flippity!” sighed the mermaid.  “I’m sorry, for he was the prettiest and nicest mackerel in your whole flock.”

“What does it mean?” asked Trot.  “How did Flippity go to glory?”

“Why, he was caught by a hook and pulled out of the water into some boat,” Merla explained.  “But these poor stupid creatures do not understand that, and when one of them is jerked out of the water and disappears, they have the idea he has gone to glory, which means to them some unknown but beautiful sea.”

“I’ve often wondered,” said Trot, “why fishes are foolish enough to bite on hooks.”

“They must know enough to know they’re hooks,” added Cap’n Bill musingly.

“Oh, they do,” replied Merla.  “I’ve seen fishes gather around a hook and look at it carefully for a long time.  They all know it is a hook and that if they bite the bait upon it they will be pulled out of the water.  But they are curious to know what will happen to them afterward, and think it means happiness instead of death.  So finally one takes the hook and disappears, and the others never know what becomes of him.”

“Why don’t you tell ’em the truth?” asked Trot.

“Oh, we do.  The mermaids have warned them many times, but it does no good at all.  The fish are stupid creatures.”

“But I wish I was Flippity,” said one of the mackerel, staring at Trot with his big, round eyes.  “He went to glory before I could eat the hook myself.”

“You’re lucky,” answered the child.  “Flippity will be fried in a pan for someone’s dinner.  You wouldn’t like that, would you?”