The Nautilus has a beautiful spiral mother-of-pearl shell, and when on
a voyage it uses part of its body as a sail, and the long tentacles
about its mouth help it in swimming. It spends a good deal of its time
on the bottom of the ocean near the coral reefs, and can creep along
very quickly, supporting itself with its head and tentacles. The head
is flat and muscular and acts as a defense to the opening of the
shell, and the Nautilus also possesses very strong jaws which it makes
good use of in crushing crabs and other shell-fish on which it feeds.

Sammy found it rather difficult at first to come to a friendly
understanding with the Nautilus, for the gallant little mariner was
somewhat shy of strangers, and would frequently show his distrust by
suddenly drawing in his tentacles, upsetting his shell, and dropping
to the bottom of the Lagoon, thus effectually cutting short any
conversation. But this was only his way of protecting himself; after a
time he grew bolder, and being a true sailor spun many a wonderful
yarn about his voyages.

To the Nautilus Sammy was indebted for a most important piece of
information. It happened in this wise. He had now spent several weeks
in Coral-Land. He knew the Lagoon thoroughly from end to end, the best
feeding and hiding-places, the delightful caverns and caves in the
reefs, and was on friendly terms with almost all its inhabitants. But
a fish is a restless creature, and, strange to say, Sammy was daily
growing more and more weary of this peaceful Lagoon. It was all very
wonderful to be sure, the beautiful coral in its lovely colors and
fantastic shapes, the gay flowers and plants, the strange shells, and
the brilliant, sparkling fish; but then the warm water _was_
certainly enervating, and the mountain stream that he called home had
many charms, now that he was no longer there.