The Collaborative International Dictionary of English v.0.48:

Polygastrica \Pol`y*gas"tri*ca\ (-tr[i^]*k[.a]), n. pl. [NL. So
   called because they were supposed to have several stomachs,
   or digestive cavities.] (Zool.)
   The Infusoria. [Obs.]
   [1913 Webster] Polygenesis