The Collaborative International Dictionary of English v.0.48:

Ectolecithal \Ec`to*lec"i*thal\, a. [Ecto- + Gr. ? the yolk of
   an egg.] (Biol.)
   Having the food yolk, at the commencement of segmentation, in
   a peripheral position, and the cleavage process confined to
   the center of the egg; as, ectolecithal ova.
   [1913 Webster]