You must first make three little men to
dive in it before it can be said to be perfect; and that would be rather
difficult, I fear, for two of them would require to be philosophers.
But hallo! what's this?--I say, Ralph, look here! There's one o' your
crabs up to something uncommon. It's performing the most remarkable
operation for a crab I ever saw--taking off its coat, I do believe,
before going to bed!"

We hastily stooped over the tank, and certainly were not a little amused
at the conduct of one of the crabs which still survived its companions.
It was one of the common small crabs, like to those that are found
running about everywhere on the coast of England. While we gazed at it
we observed its back to split away from the lower part of its body, and
out of the gap thus formed came a soft lump which moved and writhed
unceasingly. This lump continued to increase in size until it appeared
like a bunch of crab's legs; and, indeed, such it proved in a very few
minutes to be, for the points of the toes were at length extricated from
the hole in its back, the legs spread out, the body followed, and the
crab walked away quite entire, even to the points of its nipper-claws,
leaving a perfectly entire shell behind it, so that, when we looked, it
seemed as though there were two complete crabs instead of one.

"Well," exclaimed Peterkin, drawing a long breath, "I've _heard_ of a
man jumping out of his skin and sitting down in his skeleton in order to
cool himself, but I never expected to _see_ a crab do it!"

We were, in truth, much amazed at this spectacle, and the more so when
we observed that the new crab was larger than the crab that it came out
of. It was also quite soft, but by next morning its skin had hardened
into a good shell. We came thus to know that crabs grow in this way,
and not by the growing of their shells, as we had always thought before
we saw this wonderful operation.

Now I considered well the advice which Jack had given me about preparing
my tank, and the more I thought of it the more I came to regard it as
very sound and worthy of being acted on. So I forthwith put his plan in
execution, and found it to answer excellently well--indeed, much beyond
my expectation; for I found that after a little experience had taught me
the proper proportion of seaweed and animals to put into a certain
amount of water, the tank needed no further attendance. And, moreover,
I did not require ever afterwards t