All animals, simple or complex, are able of performing necessary bodily functions. One of these functions is Locomotion. Motility is one of the characteristics and basic attributes of all forms of life. It is a common property of protoplasm. Intracellular streaming movement of cytoplasm, Chromosome movement throughout cell division, special kinds of cell motility within the body of metazoans, like movement of intestinal villi, transport of substances in the axons, and ciliary beating in the respiratory tubes, etc. are all instances. Though, locomotion involves movement of the body like a whole from place to place. This is brought about in different animals in different ways and includes different structures in various animals. In this unit you will study the several types of locomotion exhibited and the structural components of the locomotory machinery between different non-chordate animals.