The Collaborative International Dictionary of English v.0.48:

Endosarc \En"do*sarc\, n. [Endo- + Gr. ?, ?, flesh.] (Biol.)
   The semifluid, granular interior of certain unicellular
   organisms, as the inner layer of sarcode in the am[oe]ba;
   entoplasm; endoplasta.
   [1913 Webster]