Notes from Oscar Schotte's lecture. Trinkaus continues his notes on the development of the egg with information on 'internal potencies', 'visibles structure', and 'Invisible structure', then begins a new section on 'External Factors" with a diagram of a two-cell embryoLecturer: O. Schotte, Lecture "The Echinoderm egg, its structure and its relation to the orientation of the embryo. (2:00 P.M.)" (Information taken from the 1939 Embryology Course Book)Page 65 of 113 from the first notebook of lecture and laboratory notes that John P. Trinkaus took during his time as a student in the Marine Biological Laboratory Embryology Course in 1939 in Woods Hole, MA