part of part_of part of part_of develops_from develops from embryonic structure embryonic structure 胚胎结构 somatopleure undifferentiated genital tubercle genital tubercle phallic tubercle the embryonic anlage of the external genitalia, which emerges as paired swellings ventral to the cloacal membrane, is proposed to be derived from all three germ layers, and gives rise to the penis, clitoris, scrotum, labia, and foreskin tuberculum genitale tuberculum phallicum undifferentiated genital tubercle indifferent external genitalia indifferent external genitalia 未分化外部生殖器