Notes from Donald Costello's lectures. Trinkaus concludes his notes on Costello's "Fertilization" lecture with information about fertilization theories from different scientists (Boveri, Loeb, Lillie, Chambers). Trinkaus begins notes on Costello's lecture (a "research lecture") with information on "Centrifugation of the Egg"Lecturer: D. P. Costello, Lecture "Fertilization."| Lecturer D.P. Costello, Lecture "Some effects of centrifugal force on the eggs of Asterias and of Nereis" (Information taken from the 1939 Embryology Course Book)Page 7 of 72 from the second 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