230 LITTLE FOLKS 
could see him, because, whichever way he approached it with his 
hand, the creature's spines were instantly turned that way, as if for 
protection. 
The ways of the Sea Urchin are interesting, though it is only 
since he has been induced to live in an aquarium that men have 
been able to study them much. I have spoken of his droll way of 
walking, rolling over and over, and of his making for himself a safe 
hole in the rock, but some of them have another way of hiding. 
They dig holes in the sand with their spines, throwing the sand 
up violently as they work, and gradually sinking down, then using 
the spines on the back to draw the sand back over them, so as to 
hide them. But they have no idea of being buried alive, so they 
arrange a little hole with the same useful spines, through which 
they breathe and receive the sea water. 
A naturalist, who has studied them in his aquarium, tells of 
some odd habits of theirs. They are very fond of lifting up little 
stones, which lie on the bottom of the tank. One will attach some 
of his feet to a pebble, and holding it up over his back, will walk 
up on a rock, and stay there a long time, with his stone held up 
over him, like an umbrella. Sometimes he will carry three or four 
stones up, and again he will collect so many of them that he will be 
nearly covered with pebbles. What is the object of this perform- 
ance, no one can guess. 
Sea Urchins are sometimes called Sea Eggs, because they are 
good to eat. They are caught in wooden pinchers, from shallow 
water, or in a gloved hand. They are eaten raw, like oysters, or 
boiled, like eggs. They were a favorite dish among the Greeks and 
Romans, served with wine and parsley. 
There are other Urchins besides the common ones of which I 
have told you. On the opposite page is a picture of one which is 
very large and of a bright scarlet color. This picture is not as large 
as the creature himself, for he measures six inches across. He is 
not hard and stiff, like most of his family, but can flatten himself 
down, like a cake. He can do this because the hundreds of pieces, 
of which his shell is made, are not joined solidly, as in most Sea 
Urchins, but lap over each other, and are united by a sort of mem- 
brane, which is elastic, of course, and allows the shell to change its 
shape. 
There is one kind of Urchin called the Piper Urchin, and a 
whole family called Heart Urchins. These last, have very slendei 
