moving its spines, tilting its body along from one place to another on
the bed of the sea. It can do much more than that. Like its cousin the
Starfish, it has numerous tube-feet, so you would not be surprised to
see this prickly ball walk up the face of a rock.

The tube-feet, or sucker-feet, are fixed to the shell in much the same
way as the spines. They can be bent this way or that. If the Urchin is
on a rock he clings tightly with these sucker-feet; then, if he wishes
to move away, you will see the long thin tubes stretch out and bend
about. They fix themselves to the rock, and the animal is drawn along.

[Illustration: TEST OR SHELL OF A SEA-URCHIN.]

Besides these spines and suckers, the Sea-urchin owns another set of
tools. Scattered over it, among the spines, are many tiny rods tipped
with little teeth or pincers. You will not be able to see them, except
under a magnifying glass. Of what use are these strange little pincers
or rods? It is thought that the Urchin uses them in several ways. They
may help in capturing small prey, or they may be used when the creature
has to fight a larger enemy. They are also certainly of use as cleansing
tools. That is to say, they can pick off tiny scraps of weed or dirt
which settle on the animal's body. Some Starfishes also own pincers of
this sort, but they are not so perfect as those of the funny little
Urchin. We must not forget that all these spines, tube-feet, and pincers
are worked by a set of muscles.

In the centre of the Urchin's shell is its mouth. The Starfish, we
found, had a terrible mouth, but that of the Urchin is worse still. Not
only is it of great size, but it is fitted with strong jaws and five
long, sharp teeth, You may see them poking out from the mouth of the