Notes from Oscar Schotte's lecture. Trinkaus begins notes on the 'Visible Polarity in the Echinoderm Egg' with two labeled diagrams and notes on the history of research on the topic.Lecturer: O. Schotte, Lecture "Development of the Echinoderm egg according to Horstadius" (Information taken from the 1939 Embryology Course Book)Page 71 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