This confocal image shows a 13.5 days post coitum female mouse gonad at high magnification (x40). The developing ovary and mesonephros were fluoresently stained with an endothelial and germ cell marker called PECAM (platelet endothelial cell adhesion molecule). The long projections extending from the right are the endothelial cells migrating into the developing ovary from the adjacent mesonephros. The circular cells are the germ cells in the developing ovary.