HOW STAR-FISH WALK. 83 
weird life he leads, clinging to the wet roofs and sides 
of caverns, or hiding under large stones, or wandering 
over the sand at low tide with the water rippling 
gently over his body : the sea must appear to him 
in a very different light from what it does to the 
coral-builders or jelly-fish, as they wave about their 
soft tentacles and bathe them in the element they 
love. 
For the real interest of the star-fish is not in the 
.sea above, but in the solid ground below. He cares 
for the water only that he may get oxygen out of it 
to breathe, for though he can swim when it is neces- 
sary, yet he is really a creeping animal, and loves to 
climb over the rocks, or poke about the sandy bottom 
with his mouth down to the ground, feeding on mus- 
sels and other shell-fish wherever he can find them. 
No ghost could glide more smoothly or with less 
noise than he does as he wanders dreamily along, 
and when he comes to a wall of rock or a hollow in 
the sand he does not avoid them, but bends his body 
over the one or slides down the other, hugging the 
ground closely as he goes. And yet the machinery 
by which he moves is nowhere to be seen, nor will 
you be able to guess how it works, till you pick up the 
first living star-fish left upon the shore as the tide 
goes down, and put it into a glass pan or jar of salt 
water. Then you will be able to watch this curious 
movement through the glass. At first he will lie 
helplessly at the bottom, but very soon, although as 
you look down upon him you will not see any special 
part move, the whole body will begin to glide slowly 
along. Now lift the jar and look at the under part 
of the body. You will see hundreds of tiny trans- 
