‘THE SCHOOL OF THE SHORE 39 
grappling-cells. Just as we draw back our 
finger from a hot plate without even willing 
it, because of a circuit between nerve-cells 
that feel, nerve-cells that command, and 
muscle-cells that obey, so the sea-anemone 
folds its tentacles about an incautious worm. 
This is called reflex action. The sea-anemone 
may be deceived by giving the tentacles a little 
roll of wet paper to catch; but after it has 
been cheated twice or thrice it has had enough 
and will not close up any more. Sometimes it 
catches too big an animal, like a periwinkle, 
which struggles hard and bursts through the 
enswathing tentacles. ‘The sea-anemone can 
flourish for a long time without more than 
microscopic food; it might be called an easy- 
going feeder. One has been known to live for 
sixty years. 
Right up to the high-tide mark on rocks, 
pillars of piers, stray pieces of wood, and even 
on living animals, like crabs, we see a crusting 
of rock-barnacles or acorn-shells. When the 
tide is out the roof of the rampart that encloses 
the animal is kept tightly shut; but as soon as 
the water, or even the salt spray, reaches it, 
the acorn-shell opens its four valves. When it 
is covered with water it begins to feed without 
