Childrens Illustrated Encyclopedia

147

JELLYFISH

The sea wasp jellyfish

uses its tentacles to

sting fish. Tentacles

contain venom that

is painful to humans

and can cause death.

CLOWN FISH

These fish live in

harmony with sea

anemones. The thick,

slimy mucus on their

bodies keeps them

safe from the stinging

cells. Clown fish keep

anemones clean by

feeding on particles

of food among their

waving tentacles.

CORAL SHAPES

The shape of a coral depends on the

arrangement and growing pattern of the

tiny polyps that build it. Corals can be

dazzling in color and extraordinary in

shape, resembling all kinds of objects. This

Carijoa coral looks like a branching tree.

Corals grow in shallow

water around an island.

Coral reef builds

up as island sinks.

Island disappears,

leaving an atoll.

ANEMONE

As a fish stops

struggling, the

anemone’s tentacles

shorten and pull it

into the mouth, through

to the stomach chamber in

the “body” of the anemone.

Any undigested remains

pass out the same way.

HYDRA

The tiny hydra is a freshwater

polyp that lives in ponds. It may

be green, brown, or gray in color.

Hydras feed on other tiny water

creatures that they catch with

their tentacles. Each tentacle

has stinging cells that contain

poison to paralyze the prey.

Hydras reproduce by growing

“buds” on their “stalk.” The

buds break off to form new

hydras. This is a form of

asexual reproduction.

HOW CORAL REEFS ARE FORMED

Corals live in shallow

water around an island

where bright sunlight

makes them grow.

As movements in

Earth’s surface make

the island sink, corals

form a reef. Finally, the

island disappears, leaving

a ring of reefs called an atoll.

Whip Common sea anemone

thrown

out

Stinging tip

Coiled

whip

Stinging cell body

Trigger

STINGING CELLS

Each jellyfish tentacle is armed with deadly weapons. If a fish

touches a tentacle, stinging cells containing tiny coiled-up

threads are triggered into action. They shoot out a hollow

whip like a harpoon, injecting paralyzing poison into the prey.

MAN-OF-WAR

The Portuguese man-of-war is not one jellyfish. It is a floating

colony of hundreds of jellyfish-like creatures known as polyps.

Some polyps form the float, which drifts on the water; others

bear stinging tentacles for paralyzing prey; still others digest

the prey and pass the nutrients through the body.

Clown fish

Anemone slowly engulfs

a trapped fish.

CORALS,

jellyfish Corals, anemones, and

IN THE WARM, TROPICAL SEAS surrounding coral islands

live some of the most fascinating sea creatures.

Despite being so different in appearance, corals,

jellyfish, and anemones belong to the same

family. The fabulous corals that make up coral reefs

are created by little animals called polyps, which look

like miniature sea anemones. Every polyp builds a

cup-shaped skeleton around itself, and as the

polyps grow and die, their skeletons mass together

to create a coral reef. Unlike coral-building

polyps, jellyfish can move around freely,

trailing their long tentacles below

their soft bodies as they swim. Some

jellyfish float on the surface and

are pushed along with the current.

Anemones anchor themselves to

rocks, where they wait for fish

to swim through their tentacles.

Carijoa coral

Find out more

Animals

Deep-sea wildlife

Ocean wildlife

Tentacles trail more
than 50 ft (15 m) from
a man-of-war.

Sea wasp