are called the Pteroceras Scorpio; and three others besides, one
young and two grown up ones, which go by the name of Cypraea Exanthema.

He told Charley to put all these shells together in his Museum, because,
in certain particulars, they are alike, and all have, besides their own
special names, the same generic name of Gasteropoda. They are so called,
because they have something like a foot proceeding from the body which
they use for moving about. Some of them have a distinct head, furnished
with feelers, and eyes, and some means of smelling and hearing. Commonly
the shell has but one valve, but sometimes more. Their shell is
secreted or made out of their skin, which is called a mantle. I ought to
tell you also, that all these shell-fish have another name, still more
general, which is Mollusca, or Molluscs.

[Illustration: ADULT SHELLS. YOUNG SHELL.

CYPRAEA EXANTHEMA.]

The Scallop Charley must have read about before his uncle gave it to
him, for pilgrims to the Holy Land, many hundred years ago, used to wear
it, as a badge on their hats or caps. It has two valves, like the
oyster, which are united by a strong and very elastic hinge. It has also
a strong muscle, by which it can, as it pleases, open its valves or
keep them tightly shut. It helps to move itself about by rapidly opening
and closing its shell. It is found in the European seas and all along
the southern coasts of England.

[Illustration: SCALLOP.]

[Illustration: NAUTILUS]

"Here, Charley," said uncle Brown, "is a very beautiful shell for you,
called the Nautilus. The animal is very plentiful in the Mediterranean
Sea. It has several arms, which, people used to think, it stretched out
like the sails of a ship, and so skimmed over the water in its shell.
But this is a mistake, for it covers its shell with these arms, and in
fact makes the shell by a secretion from them. It pushes itself through
the water by throwing water from a tube, which it has.

"The shell is always elegant, but the colors of the living animal are
very beautiful."

"Oh uncle," cried Charley, "what wonderful and nice things you have
told me? Can I find such things in books."

"Certainly, you can," replied the uncle, "for it is there I got most of
what I have told you."

"Then," said, Charley, "I mean to read all the books, telling about
these things, that I can get, if father will let me, for I should like
to do that better, than to be a farmer or a merchant. Do you th