thrown away outside the door.

Now comes the strangest thing of all. As a baby, the Barnacle is a free
swimming creature. It has three pairs of legs, a tail, a useful mouth,
and one eye. After kicking about in the sea for some time, and changing
its skin, it changes its shape entirely. It now looks more like a tiny
mussel. It has two little "shells," two eyes, legs, and feelers. Now its
swimming days are nearly over, and it must settle down. It gives up
eating, and roves about looking and feeling for a place to settle on.

Finding a suitable spot, the little animal stands on its head. Then a
kind of glue is formed, which fixes it for life to that place, head
down. The two shells and the two eyes are now thrown off. The Barnacle
quickly builds up a shelly house, and, after a life of adventure and
change, becomes a fixed Barnacle for the rest of its days.

For many years people knew little of this strange animal. All its
wonderful changes, and the way its body is made, tell us plainly that
the Barnacle is actually first cousin to the Crab, Lobster, Shrimp and
Prawn! It belongs to the class known as the _Crustacea_; but, for some
reason or other, it has chosen to live its grown-up life fixed to a
rock.


EXERCISES

1. How does the Shrimp swim?

2. Of what use are Shrimps and Prawns in the sea?