The Collaborative International Dictionary of English v.0.48:

Sporocyst \Spo"ro*cyst\ (-s[i^]st), n. [Gr. ? seed + ? bladder.]
   1. (Zool.) An asexual zooid, usually forming one of a series
      of larval forms in the agamic reproduction of various
      trematodes and other parasitic worms. The sporocyst
      generally develops from an egg, but in its turn produces
      other larvae by internal budding, or by the subdivision of
      a part or all of its contents into a number of minute
      germs. See Redia.
      [1913 Webster]

   2. (Zool.) Any protozoan when it becomes encysted and
      produces germs by sporulation.
      [1913 Webster]