Changes in red blood cell distribution and density in the embryo proper and yolk sac.

Embryos were dissected into embryo proper and yolk sac and dissociated into single cells, and total cells and erythroblasts (benzidine positive) were enumerated. (A) Absolute numbers of erythroblasts per tissue were plotted, and (B) percentages of total cells that were erythroblasts were plotted. Error bars indicate SEM (n = 5-13).