Notes from Oscar Schotte's lecture. Trinkaus continues his notes from the previous page on recombination experiments for the different cell stages (with diagrams)Lecturer: O. Schotte, Lecture "Experimental embryology of Echinoderms I" (Information taken from the 1939 Embryology Course Book)Page 105 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