Notes from Oscar Schotte's lecture. Trinkaus continues notes from the previous page on Runstrom's double gradient theory. Then begins notes on Horstadius and 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 103 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