The Collaborative International Dictionary of English v.0.48:

Manyplies \Ma"ny*plies\, n. [Many, adj. + plies, pl. of ply a
   fold.] (Anat.)
   The third division, or that between the reticulum, or
   honeycomb stomach, and the abomasum, or rennet stomach, in
   the stomach of ruminants; the omasum; the psalterium. So
   called from the numerous folds in its mucous membrane. See
   Illust of Ruminant.
   [1913 Webster]