There may be crabs, fish, shrimps, and others in the pool.  If you look for a moment, and then walk to the next pool, your hunting will not have much result.  It is best to lie down and wait patiently, gazing into the clear water of the pool.  The little inhabitants are hidden in the dark corners under the rock ledges, or buried under stones and sand; or they may be hiding in those thick clumps of mussels—­a favourite lurking-place; or else tucked away in the friendly shelter of the seaweed.

Knowing their dodges, you will soon become clever at finding them.  Some seaside dwellers, such as prawns, are almost transparent in the water.  Others, like baby crabs, are green or brown like the weed in which they hide.  Even the sharp eyes of the seagulls must be deceived by this trick.

What a strange life they lead, these creatures of the shore!  At times they are deep under water, and they form part of the teeming life of the ocean floor.

Then the tide falls and uncovers them.  They are in the full light of day again, the sun shines on them.  Most of them cannot escape to the sea, and so must face the enemies which prowl along the shore looking for prey.  So, from one tide to the next, the rock-pool is like a prison containing prisoners of the strangest sort.

[Illustration:  Gulls. 1.  Common gulls. 2.  Lesser black gull. 3.  Glaucous gulls.]

EXERCISES

1.  How is the sand formed?

2.  Give the names of some of the animals to be found in the rock-pools.

3.  Where do these animals hide?

4.  Prawns and shore-crabs are not easily seen; why is this?

LESSON III.

BIRDS OF THE SHORE.

On some parts of our coast we find steep cliffs, with the sea beating wildly at their feet.  Elsewhere there is a sloping beach of sand and shingle with, perhaps, dark rocks showing at low tide.  We explored such a beach as that in our last lesson.  There are long, long stretches of sand and thin grass in other places, or else mile after mile of muddy, dreary, salt marshes.

Birds are to be found on every kind of coast.  Some, like the Seagull, wander far and wide.  Others keep to the cliffs, and many find all they need in the wide mud-flats.  Such an army is there of these shore birds, that we cannot even glance at them all in this lesson.  So we will take a few of them only—­the Black-headed Gull, the Cormorant, the Ringed Plover, the Oyster-catcher and the Redshank.

Out of all the many kinds of Gulls, you know the Black-headed one best.  If you live in London you can see and hear him, for he and his cousins have swarmed along the Thames of late years.  They find food there, and kind people enjoy feeding the screaming birds as they wheel in graceful flight over the bridges and Embankment.