# Term Identifier embryo Body_part ectoderm Body_part yolk-sac Body_part umbilicus Body_part caudal folds Body_part head Body_part buccopharyngeal membrane Body_part head of the embryo Body_part fore-gut Body_part chorion Body_part mesoderm Body_part body-stalk Body_part caudal fold Body_part tail fold Body_part hind-gut Body_part umbilical vesicle Body_part duct Body_part