Animals Without Blood
Flatworms: Flatworms don’t have blood because they lack red blood cells.
Nematodes: Nematodes have no circulatory system, they only have a nervous system.
Jellyfish: Jellyfish don’t have blood because they use hemocyanin instead of hemoglobin for oxygen transport.
Sea Anemones: Sea anemones do not have blood, they have cells called nematocysts that contain stinging cells.
Corals: Coral has no blood, but it does have a skeleton made up of calcium carbonate, which is similar to bone.
Sponges: Sponges does not have blood because they are made up of cells called mesenchymal stem cells.
Hydra: Hydra do not have blood because they are made up of cells called mesenchymal stem cells.