The Collaborative International Dictionary of English v.0.48:

Monitorial \Mon`i*to"ri*al\, a.
   1. Of or pertaining to a monitor or monitors.
      [1913 Webster]

   2. Done or performed by a monitor; as, monitorial work;
      conducted or taught by monitors; as, a monitorial school;
      monitorial instruction.
      [1913 Webster]