[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
animal, and feel for yourself how hard they are.
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