Editing Sea cucumber (section)

===Digestive system===
[[File:Holothuroidea (Sea cucumber feeding).jpg|thumb|right|A sea cucumber atop gravel, feeding]]
A [[pharynx]] lies behind the mouth and is surrounded by a ring of ten [[calcareous]] plates. In most sea cucumbers, this is the only substantial part of the skeleton, and it forms the point of attachment for muscles that can retract the tentacles into the body for safety as for the main muscles of the body wall. Many species possess an [[oesophagus]] and [[stomach]], but in some the pharynx opens directly into the [[intestine]]. The intestine is typically long and coiled, and loops through the body three times before terminating in a [[cloaca]]l chamber, or directly as the [[anus]].<ref name=IZ/>