• Parkway West High School

• SCIENCE 101

Cnidarians-A Coloring Worksheet

Cnidarians include corals, jellyfish, sea anemones, and hydra. Jellyfish (Figure 1) are fish-eating animals

that float in the sea - only a few jellyfish live in freshwater. They have soft bodies and long, stinging, poisonous

tentacles that they use to catch fish. Label and color the tentacles green. The tentacles hang down from an

umbrella-shaped medusa. Label the medusa. The jellyfish has two cell layers --- an outer ectoderm and an inner

endoderm. Label and color the ectoderm red and the endoderm orange. Between these layers is a jellylike

material called mesoglea. Label and color the mesoglea pink. The mouth is located on the underside in the center

of the tentacles. Label the mouth. The mouth opens into the gastrovascular cavity where their prey is digested.

Label and color the gastrovascular cavity tan.

Venom or a paralyzing poison is sent out through stinging cells called cnidocytes (Figure 2). Label and

color the cnidocyte yellow. Inside the cnidocytes, is a coiled, poisonous thread that can shoot out to paralyze prey

with poison. This harpoon-like structure is called the nematocyst (Figure 3). Cnidocytes have a trigger that when

touched shoot out the nematocyst. Label and color the nematocyst orange. Label the trigger on the cnidocyte