oscis, all full of sharp teeth, with which they bore through
the shells of other mussels and eat up the creatures inside.

"Persons who collect shells and form cabinets of them for their
amusement," said Mr. Brown, "are not naturalists. They care nothing
about the animal which lived in the shell, when it was in the sea. All
they wish for, is to have a pretty and complete collection, containing
as many different kinds and as rare shells as possible."

"I should like to have a pretty collection," said Charley.

[Illustration: MIDAS'S EAR.]

"So you will," said Mr. Brown, "but I hope you will learn as much as you
can of the natural history of the animals, to whom the shells wore once
attached."

"I will try," said Charley.

"Now here is one," said Mr. Brown taking the shell from his pocket,
"called the Bulla Ampulla." Observe it.

It is shaped much like an egg, though somewhat round, and is beautifully
spotted with white, plum-color and reddish. It is said to exist in both
the Indian and American Oceans. What you see here is only the empty
shell or covering of the animal.

[Illustration: BULLA VELUM. (TWO VIEWS.)]

It once contained a living animal, and the shell was formed by the
hardening of the soft material of its body. It grew just as your hard
finger nails grow. Here is another Bulla. This is the Bulla Velum. You
see its general shape is much like the other; but the markings are
different.

"How beautiful it is!" said Charley. "Dear uncle, I can never repay you
for your kindness in giving me such elegant things as these. And some of
them are very costly too."

"They cost me nothing," said Mr. Brown. "They were brought and presented
to me by sea captains, and supercargoes in my service. Even that
Wentle-trap was a sea captain's gift; and when I told its real value, he
insisted the more on my keeping it But most of the shells are
cheap.--But that is of no consequence.

"I will tell you, Charley," continued Mr. Brown, "how you can repay and
gratify me. It is by industry and good conduct.

"I wish you to grow up to a first-rate man, you must begin by being a
first rate boy. When I am out here, and happen to remember any thing
that has, in any way, done me good in my life time, I will tell it to
you, if you will promise to try to keep it in mind and to act upon it.
Will you promise?"

"Oh yes, uncle, I will promise to try to remember and do what you tell
me."

"Well, then, I'll tell you one thing now,