Dictionary.net

• The theory that certain portions of the ovum are predestined to develop into certain organs or parts.

1920 - A dictionary of scientific terms.
By Henderson, I. F.; Henderson, W. D.

• [Latin] The theory that certain portions of the ovum are predestined to develop into certain organs or parts (biol.).

1920 - A dictionary of scientific terms (6th edition)
By J.H. Kenneth