endophragma

from The Collaborative International Dictionary of English v.0.48

Endophragma \En`do*phrag"ma\, n. [NL., fr. Gr. 'e`ndon + fra`gma
   a fence.] (Zo["o]l.)
   A chitinous structure above the nervous cord in the thorax of
   certain Crustacea.
   [1913 Webster]