Source : Webster's Revised Unabridged Dictionary (1913)

Episodic \Ep`i*so"dic\, Episodical \Ep`i*so"dic*al\, a. [Cf. F.
   ['e]pisodique. See {Episode}.]
   Of or pertaining to an episode; adventitious. --
   {Ep`i*so"dic*al*ly}, adv.

         Such a figure as Jacob Brattle, purely episodical
         though it be, is an excellent English portrait. --H.
                                                  James.

Source : WordNet®

episodically
     adv : in an episodic manner