The three swam slowly along, quite enjoying the cool depths of the water. Every little while they met with some strange creature—or one that seemed strange to the earth people—for although Trot and Cap'n Bill had seen many kinds of fish, after they had been caught and pulled from the water, that was very different from meeting them in their own element, "face to face," as Trot expressed it. Now that the various fishes were swimming around free and unafraid in their deep-sea home, they were quite different from the gasping, excited creatures struggling at the end of a fishline or flopping from a net.  
Before long they came upon a group of large fishes lying lazily near the bottom of the sea. They were a dark color upon their backs and silver underneath, but not especially pretty to look at. The fishes made no effort to get out of Merla's way and remained motionless except for the gentle motion of their fins and gills.
 
"Here," said the mermaid, pausing, "is the most aristocratic family of fish in all the sea."
 
"What are they?" asked the girl.
 
"Codfish," was the reply. "Their only fault is that they are too haughty and foolishly proud of their pedigree."
 
Overhearing this speech, one codfish said to another in a very dignified tone of voice, "What insolence!"
 
"Isn't it?" replied the other. "There ought to be a law to prevent these common mermaids from discussing their superiors."
 
"My sakes!" said Trot, astonished. "How stuck up they are, aren't they?"
 
For a moment the group of fishes stared at her solemnly. Then one of the remarked in a disdainful manner, "Come, my dear, let us leave these vulgar creatures."
 
"I'm not as vulgar as you are!" exclaimed Trot, much offended by this speech. "Where I come from, we only eat codfish when there's nothing else in the house to eat."
 
"How absurd!" observed one of the creatures arrogantly.
 
"Eat codfish indeed!" said another in a lofty manner.
 
"Yes, and you're pretty salty, too, I can tell you. At home you're nothing but a pick-up!" said Trot.
 
"Dear me!" exclaimed the first fish who had spoken. "Must we stand this insulting language—and from a person to whom we have never been introduced?"
 
"I don't need no interduction," replied the girl. "I've eaten you, and you always make me thirsty."
 
Merla laughed merrily at this, and the codfish said, with much dignity, "Come, fellow aristocrats, let us go."
 
"Never mind, we're going ourselves," announced Merla, and followed by her guests the pretty mermaid swam away.
 
"I've heard tell of codfish aristocracy," said Cap'n Bill, "but I never knowed 'zac'ly what it meant afore."
 
"They jus' made me mad with all their airs," observed Trot, "so I gave 'em a piece of my mind."
 
"You surely did, mate," said the sailor, "but I ain't sure they understand what they're like when they're salted an' hung up in the pantry. Folks gener'ly gets stuck-up 'cause they don't know theirselves like other folks knows 'em."
 
"We are near Crabville now," declared Merla. "Shall we visit the crabs and see what they are doing?"
 
"Yes, let's," replied Trot. "The crabs are lots of fun. I've often caught them among the rocks on the shore and laughed at the way they act. Wasn't it funny at dinnertime to see the way they slid around with the plates?"
 
"Those were not crabs, but lobsters and crawfish," remarked the mermaid. "They are very intelligent creatures, and by making them serve us we save ourselves much household work. Of course, they are awkward and provoke us sometimes, but no servants are perfect, it is said, so we get along with ours as well as we can."
 
"They're all right," protested the child, "even if they did tip things over once in a while. But it is easy to work in a sea palace, I'm sure, because there's no dusting or sweeping to be done."
 
"Or scrubbin'," added Cap'n Bill.
 
"The crabs," said Merla, "are second cousins to the lobsters, although much smaller in size. There are many families or varieties of crabs, and so many of them live in one place near here that we call it Crabville. I think you will enjoy seeing these little creatures in their native haunts."
 
They now approached a kelp bed, the straight, thin stems of the kelp running far upward to the surface of the water. Here and there upon the stalks were leaves, but Trot thought the growing kelp looked much like sticks of macaroni, except they were a rich red-brown color. It was beyond the kelp—which they had to push aside as they swam through, so thickly did it grow—that they came to a higher level, a sort of plateau on the ocean's bottom. It was covered with scattered rocks of all sizes, which appeared to have broken off from big shelving rocks they observed nearby. The place they entered seemed like one of the rocky canyons you often see upon the earth.
 
"Here live the fiddler crabs," said Merla, "but we must have taken them by surprise, it is so quiet."
 
Even as she spoke, there was a stirring and scrambling among the rocks, and soon scores of light-green crabs were gathered before the visitors. The crabs bore fiddles of all sorts and shapes in their claws, and one big fellow carried a leader's baton. The latter crab climbed upon a flat rock and in an excited voice called out, "Ready, now—ready, good fiddlers. We'll play Number 19, Hail to the Mermaids. Ready! Take aim! Fire away!"
 
At this command every crab began scraping at his fiddle as hard as he could, and the sounds were so shrill and unmusical that Trot wondered when they would begin to play a tune. But they never did; it was one regular mix-up of sounds from beginning to end. When the noise finally stopped, the leader turned to his visitors and, waving his baton toward them, asked, "Well, what did you think of that?"
 
"Not much," said Trot honestly. "What's it all about?"
 
"I composed it myself!" said the Fiddler Crab. "But it's highly classical, I admit. All really great music is an acquired taste."
 
"I don't like it," remarked Cap'n Bill. "It might do all right to stir up a racket New Year's Eve, but to call that screechin' music—"
 
Just then the crabs started fiddling again, harder than ever, and as it promised to be a long performance, they left the little creatures scraping away at their fiddles as if for dear life and swam along the rocky canyon until, on turning a corner, they came upon a new and different scene.
 
There were crabs here, too, many of them, and they were performing the queerest antics imaginable. Some were building themselves into a pyramid, each standing on edge, with the biggest and strongest ones at the bottom. When the crabs were five or six rows high, they would all tumble over, still clinging to one another and, having reached the ground, they would separate and commence to build the pyramid over again. Others were chasing one another around in a circle, always moving backward or sidewise, and trying to play "leapfrog" as they went. Still others were swinging on slight branches of seaweed or turning cartwheels or indulging in similar antics.
 
Merla and the earth people watched the busy little creatures for some time before they were themselves observed, but finally Trot gave a laugh when one crab fell on its back and began frantically waving its legs to get right-side-up again. At the sound of her laughter they all stopped their play and came toward the visitors in a flock, looking up at them with their bright eyes in a most comical way.
 
"Welcome home!" cried one as he turned a back somersault and knocked another crab over.
 
"What's the difference between a mermaid and a tadpole?" asked another in a loud voice, and without a pause continued, "Why, one drops its tail and t............