Urogenital system of the 18-mm embryo.
Keywords: allantois, cloacal membrane (anal part), female duct, genital tubercle, gonad, mesonephric duct, mesonephros, metanephros, opening of female duct into peritoneal cavity, pelvic portion of urogenital sinus, phallic portion of urogenital sinus, rectum, suprarenal gland outline, tail remnant, urachus, ureter, urogenital sinus (bladder portion), urorectal septum
Source: Atlas of Human Embryos.