metasternum

from The Collaborative International Dictionary of English v.0.48
Metasternum \Met`a*ster"num\, n. [Pref. meta- + sternum.]
   1. (Anat.) The most posterior element of the sternum; the
      ensiform process; xiphisternum.
      [1913 Webster]

   2. (Zool.) The ventral plate of the third or last segment of
      the thorax of insects.
      [1913 Webster] Metastoma
    
from The Collaborative International Dictionary of English v.0.48
Xiphisternum \Xiph"i*ster"num\, n.; pl. {Xiphisterna}. [NL., fr.
   Gr. xi`fos a sword + sternum.] (Anat.)
   (a) The posterior segment, or extremity, of the sternum; --
       sometimes called {metasternum}, {ensiform cartilage},
       {ensiform process}, or {xiphoid process}.
   (b) The xiphiplastron. -- {Xiph"i*ster"nal}a.
       [1913 Webster]
    

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