[Illustration: THE SHRIMP.]

Some are Shrimps, and some are Prawns; how can we tell the difference?
When they are boiled the answer is easy. All the Shrimps turn brown and
the Prawns red. (The red "Shrimps" are near relations of the Prawn.) To
tell a live Shrimp from a Prawn, look at the long pointed beak which
juts out from the front of the head. That of the Prawn is toothed, like
a little saw. If the beak is quite smooth its wearer is a Shrimp.

Until Prawns are grown up, they haunt the sandy shallows with their
cousins the Shrimps. But the larger Prawns live in deeper water. They
are generally caught in traps, as are their relatives, the crab and
lobster.

Now look closely at a Prawn, and try to find how it swims. Turn it
upside down. It has ten legs; and, under each of the horny rings of its
body, you can see a pair of little paddles. They are fringed with hairs.
When the Prawn or Shrimp is not in a hurry, he swims slowly but surely
with the little paddles, or "swimmerets." If any danger threatens, he
uses his tail, in this way:--It is made of five fringed plates, which,
as you can see, spread out or close up, like a fan. As he doubles up his
body, the plates spread themselves out. They strike the water with great
force, and so send the Prawn or Shrimp quickly _backwards_. As the body
becomes straight again, the fan closes, ready for another stroke. To
move quickly, the Shrimp or Prawn merely bends his body, then
straightens it. The tail thus becomes a strong oar, driving him
backwards with rapid jerks.

Look now at the Prawn's long, hair-like feelers. There are two pairs. On
one pair are the ears, a special kind of ear for hearing in water.