The extrinsic ocular muscles in birds are derived from the prechordal plate.
D000818:Animals; D002642:Chick Embryo; D004625:Embryo, Nonmammalian / Q000502:physiology; D009132:Muscles / Q000637:transplantation; D009801:Oculomotor Muscles / Q000196:embryology* / Q000637:transplantation; D011784:Quail; D014183:Transplantation, Heterologous