Blood islands
（重定向自Haemangioblast）
![Time-lapse movie of blood islands in a chick embryo. The large green fluorescently highlighted clusters are blood islands.](/Images/godic/202501/16/-Targeting-the-hemangioblast-with-a-novel-cell-type-specific-enhancer-1471-213X-11-76-S4.ogv4325.jpg")
Blood islands are structures around the developing embryo which lead to many different parts of the circulatory system. Blood islands arise external to the developing embryo on the umbilical vesicle, allantois, connecting stalk and chorion. They are also known as Pander's islands or Wolff's islands, after Heinz Christian Pander or Caspar Friedrich Wolff.