Peritonaeum

• (n.) Same as Peritoneum.
Found on http://thinkexist.com/dictionary/meaning/peritonaeum/

peritonaeum

peritonaeum (s), peritonea (pl), peritonaea (pl) The smooth serous membrane which lines the cavity of the abdomen, or the whole body cavity when there is no diaphragm, and, turning back, surrounds the viscera, forming a closed, or nearly closed, sac.
Found on http://www.wordinfo.info/words/index/info/view_unit/1610/16
No exact match found