Four different forms of locomotion are used by invertebrates, depending on their type of skeleton, as well as the support structures it possesses.
1. Ameboid locomotion
Ameboid locomotion is used by some protozoans. The precise mechanism of ameboid locomotion is unknown, but the outer layer of the cell does extend outward in a projection called a pseudopodium. The inner parts of the cell then flow into the pseudopodium and the cell slowly moves forward. Ameboid cells use pseudopods for both locomotion and feeding.