ABSTRACT
This chapter looks at the available studies of the development of locomotion in vertebrates from a comparative and evolutionary perspective. There is a remarkable diversity of modes of locomotion among adult vertebrates–swimming, walking, flying, to name just a few. The chapter considers the general plan of evolution of locomotion in adult vertebrates. Despite many degenerative changes that are found in adult lamprey as adaptations to their parasitic or scavenging life-style, their mode of locomotion appears to be primitive rather than degenerate and may provide insight into the ancestral vertebrate condition. It has been suggested that in sharks and in some teleost fish the early embryonic motility is myogenic rather than neurogenic. In all vertebrates studied so far, except in dogfish sharks, the C-coils occur at irregular intervals, but often at a higher frequency than the earlier head flexures. In dogfish sharks, the only species in which the movements have been shown clearly to be myogenic, the movements are rhythmical.
