The Collaborative International Dictionary of English v.0.48:

Endolymphatic \En"do*lym*phat"ic\, a. [Endo- + lymphatic.]
   (Anat.)
   (a) Pertaining to, or containing, endolymph; as, the
       endolymphatic duct.
   (b) Within a lymphatic vessel; endolymphangial.
       [1913 Webster]