Editing Body cavity (section)

==Other animals==
Organisms can be also classified according to the type of body cavity they possess, such as [[pseudocoelomates]] and [[protostome ]] [[coelomates]].<ref name="urlAnimals III — Pseudocoelomates and Protostome Coelomates">{{cite web |url=http://courses.bio.psu.edu/fall2005/biol110/tutorials/tutorial39.htm |title=Animals III — Pseudocoelomates and Protostome Coelomates |url-status=dead |archive-url=https://web.archive.org/web/20090406000959/http://courses.bio.psu.edu/fall2005/biol110/tutorials/tutorial39.htm |archive-date=2009-04-06 }}</ref>

=== Coelom ===
{{Main|Coelom}}
In [[amniote]]s and some [[invertebrate]]s, the  [[coelom]] is the large cavity lined by [[mesothelium]], an [[epithelium]] derived from [[mesoderm]]. Organs formed inside the coelom can freely move, grow, and develop independently of the body wall while fluid in the [[peritoneum]] cushions and protects them from shocks.

[[Arthropod]]s and most [[Mollusca|mollusc]]s have a reduced (but still true) coelom, the [[hemocoel]] (of an [[open circulatory system]]) and the smaller gonocoel (a cavity that contains the [[gonad]]s). Their hemocoel is often derived from the [[blastocoel]].