Expansion of the area vasculosa of the chick after removal of the ectoderm.
D000818:Animals; D001485:Basement Membrane / Q000502:physiology; D001808:Blood Vessels / Q000196:embryology*; D002642:Chick Embryo; D004475:Ectoderm / Q000502:physiology*; D008648:Mesoderm / Q000254:growth & development*