Changes in the cellular composition of peripheral blood between E11.5 and E14.5 of mouse gestation. (A,C,E,G) Cell size distribution of circulating embryonic blood cells (black area). An independent sample of adult murine red cells (gray area) is superimposed on each Coulter analysis. The x-axis represents cell volume (femtoliters); y-axis, relative cell number. (B,D,F,H) Peripheral blood cells stained with May-Grünwald-Giemsa. Some of the small and large enucleated red cells are marked with arrows and arrowheads, respectively. The scale bar represents 10 μm.