Source : Webster's Revised Unabridged Dictionary (1913)

Ectental \Ec*ten"tal\, a. [Gr. ? outside + ? inside.] (Biol.)
   Relating to, or connected with, the two primitive germ
   layers, the ectoderm and ectoderm; as, the ``ectental line''
   or line of juncture of the two layers in the segmentation of
   the ovum. --C. S. Minot.