if they were of no value whatever. To my surprise, the broken "rays"
broke again while wriggling on the ground. This is a strange habit, is
it not? Perhaps the Brittle Star has found this dodge useful in escaping
from enemies. Anyhow, the loss of an arm or two matters little, for
others grow in their place.

Another cousin of the Starfish is the Sea-urchin, a round prickly
creature rather like the burr of the sweet-chestnut tree. This mass of
prickles is not a vegetable; he is very much alive. Nature has given
many plants and animals these prickles, like fixed bayonets, for a
defence against their enemies. You will at once think of the gorse and
the hedgehog, or urchin, as some people call it. Our little Sea-urchin
has prickles, like the hedgehog, but he is really unlike any other
living creature, except, perhaps, the Starfish.

If you were to roll up a Starfish into a ball, and then stick about
three thousand spines on the ball thus made, you would have a creature
looking rather like a Sea-urchin.

Beneath the mass of spines there is a hard _test_ or shell, made of
plates joined closely together; this is the skeleton of the Sea-urchin.
Sometimes you find this strange shell on the seashore, rather dirty, and
not always sweet-smelling. You might also find Sea-urchins half-dead,
washed into the rock-pools. The shells are wonderful objects, so you
should clean them in fresh water; they are well worth the trouble of
taking home.

All over the shell you will see little rounded knobs. These show where
the spines were fixed on; each spine fits into a hole in the shell, but
so loosely that it is able to move about. The Sea-urchin can walk by