Trinkaus’s first involvement with the Embryology Course at the MBL was as a student in 1939. His mentor at Wesleyan, H. B. Goodrich, was the Director of the Embryology Course during that time and assured Trinkaus that he would receive a scholarship to cover his tuition for the course during his junior year at Wesleyan (Trinkaus 2003, 37). The course in 1939 included about 35 students, five instructors, and two assistants. As is still the case today, each day started off with a lecture by an instructor or a guest lecturer, followed by lab work on the living embryos of marine organisms that spawned from the waters surrounding Woods Hole.
In his memoir, Trinkaus lists the impressive group of guest lecturers he was privileged to witness that year: “E.G. Conklin on ascidian development, F.R. Lillie on development of the feather, Mary R. Rawles on development of feather pigment patterns, A.H. Sturtevant on genes and cytoplasm, Caswell Grave on ascidian metamorphosis, William Duryée on the lampbrush chromosomes of the amphibian germinal vesicle, and Charles Packard, the Director of the MBL, on historical aspects of embryology” (Trinkaus 2003, 41-42). The instructors of the course that year were Viktor Hamburger and Oscar Schotté; two of the most prominent biologists of the twentieth century. Both Hamburger and Schotté had studied experimental embryology with Hans Spemann at the University of Freiburg in Germany. Trinkaus recalls that getting lessons from them was one of the “outstanding privileges” of his life (Trinkaus 2003, 42). He also recalls observing the development of meroblastic cleavage in fish embryos as his most memorable experience during the labs (Trinkaus 2003, 40).
In later years, Trinkaus continued to participate in the annual Embryology Course at the MBL as an assistant and, later, as an instructor and a guest lecturer. From 1953 to 1957, Trinkaus was an official instructor and staff member of the Embryology Course. His lecture notes are included in the MBL Archives (Trinkaus Archives, Box 11, Folder 27). They indicate the myriad topics in teleost development on which Trinkaus lectured, including the techniques for preparing and handling teleost embryos in experimental settings and detailed summaries of the morphogenetic movements during gastrulation. The files also include colourful illustrations of comparative vertebrate (chordate) gastrulation as well as several extensive bibliographies, listing the latest references for theoretical and experimental work in embryology.