Editing Onychophora (section)

===Locomotion===
[[File:Peripatoides 226306189.gif|thumb|''[[Peripatoides]] aurorbis'' walking|300x300px]]
Velvet worms/Onychophora move in a slow and gradual motion that makes them difficult for prey to notice.<ref name=Read1987/> Their trunk is raised relatively high above the ground, and they walk with non-overlapping steps.<ref>{{cite book |first=Teresa |last=Zielinska |chapter=Biological Aspects of Locomotion |chapter-url=https://books.google.com/books?id=zzUojfLneW4C&pg=PA1 |pages=1–29 |doi=10.1007/978-3-7091-2772-8_1 |editor1-first=Friedrich |editor1-last=Pfeiffer |editor2-first=Teresa |editor2-last=Zielinska |year=2004 |title=Walking: Biological and Technological Aspects |isbn=978-3-211-22134-1}}</ref>
To move from place to place, the velvet worm crawls forward using its legs; unlike in arthropods, both legs of a pair are moved simultaneously. The claws of the feet are used only on hard, rough terrain where a firm grip is needed; on soft substrates, such as moss, the velvet worm walks on the foot cushions at the base of the claws.{{Citation needed|date=January 2021}}

Actual locomotion is achieved less by the exertion of the leg muscles than by local changes of body length. This can be controlled using the annular and longitudinal muscles. If the annular muscles are contracted, the body cross-section is reduced, and the corresponding segment lengthens; this is the usual mode of operation of the hydrostatic skeleton as also employed by other worms. Due to the stretching, the legs of the segment concerned are lifted and swung forward. Local contraction of the longitudinal muscles then shortens the appropriate segment, and the legs, which are now in contact with the ground, are moved to the rear. This part of the locomotive cycle is the actual leg stroke that is responsible for forward movement. The individual stretches and contractions of the segments are coordinated by the nervous system such that contraction waves run the length of the body, each pair of legs swinging forward and then down and rearward in succession. ''Macroperipatus'' can reach speeds of up to four centimetres per second,<ref name=Read1987/> although speeds of around 6&nbsp;body-lengths per minute are more typical.<ref name="doi10.1111/j.1096-3642.1950.tb01699.x">{{cite journal |doi=10.1111/j.1096-3642.1950.tb01699.x |title=The evolution of arthropodan locomotory mechanisms - Part&nbsp;I. The locomotion of peripatus |journal=Journal of the Linnean Society of London, Zoology |volume=41 |issue=282 |pages=529–570 |year=1950 |last1=Manton |first1=S.M.|doi-access=free }}</ref> The body gets longer and narrower as the animal picks up speed; the length of each leg also varies during each stride.<ref name="doi10.1111/j.1096-3642.1950.tb01699.x"/>