258 LITTLE FOLKS 
him. In the first place, he always lives in one house — the First of 
May is nothing to him. When he is a baby, about as big as a pea, 
the house is just big enough for him, and when he grows as big as 
an egg, the same house has to do for him. 
Of course, it has to be made bigger, and it isn't done as we 
make our houses larger, by adding wings, building a story higher, 
or an addition behind. He just goes to work and enlarges his 
house all over. Although it looks like a box, and seems to be made 
of one piece, like an eggshell, it is in fact, made of six hundred 
pieces, fitting so nicely together that one can scarcely see where 
they join. This curious little Sea Urchin finds lime in the sea 
water, and he takes it and enlarges his house at every joint, evenly 
and regularly, so that it is always exactly the right size for him. 
When he walks about, he has to take his house with him. 
Aren't you glad you don't have to carry your house about every- 
where you go ? If you did, you'd want it just to fit you, as the 
Urchin's house fits him. 
His back is covered with green and purple things like bristles, 
called spines, and he looks as much like a chestnut burr as anything. 
He is not a beauty, and by the side of some of the marvelous and 
exquisite creatures of the sea, he may seem dull and uninteresting, 
yet he is really one of the most wonderful creatures in the world. 
Every part of him is full of beautiful provision for his peculiar life. 
I have told you about his shell, but there are his spines quite 
as interesting. They are of a pea-green color, tipped with purple, 
and every one set upon his shell by a ball and socket joint, the most 
perfect joint known. And more than that, each one is under the 
direct control of the Urchin, so that he can raise them and lay 
them down at will. To do this, requires for every spine several 
muscles, and as the common Sea Urchin has at least twelve hun- 
dred spines, you can fancy the great number of muscles needed in 
that small body. 
But besides his twelve hundred prickly spines, Mr. Urchin has 
on the same body a great number of feet, little hollow sort of tubes, 
with suckers at the end. Of these useful little organs, he has 
the very respectable number of about a thousand, so you see he 
has no trouble to get on in the world. His feet come through 
holes, which are placed in rows all over his body, and he walks by 
turning over and over, like a ball. Sometimes his head — if he can 
be said to have a head — is up, and sometimes down. The 
