In this preliminary report, I sketch a model of narrative organization for visual embryological representations and argue that such organization was twice constructed in 19th century embryology. These constructions were stimulated by shifts of theoretical attention that changed research programs and made embryology a locus of biological unification for heredity, development, evolution, and cytology. I describe these constructions of embryological time in terms of double movements connected with a broader shift of attention toward the cellular level of biological organization in the second half of the 19th century. In the first movement, research attention shifted backward in embryological time, toward the cellular origins of germ-layers—endoderm, ectoderm, and mesoderm. Once the backward shift of attention to the earliest developmental stages had been made, cell-lineage work from the 1870s to the 1920s facilitated a second movement, tracing forward in embryological time, from the egg and early cleavage cells to future structures in larvae and adult organisms. These studies identified the fates of cells and the timing of determination of fate in development. Their technical innovations produced two visual abstractions which were important to the emergence, in the 20th century, of distinct narrative forms in transmission genetics and developmental biology: the genealogical time of the geneticist and the deterministic temporal order of the developmental biologist.