Vasa efferentia - Closed system 3. Mesonephric duct 4. Cloaca - below placental mammals 5. Thickening on floor of cloaca 2. Placental mammals 1.
Most placental mammals have extensions of uterine body, called horns, for multiple births.
The cloacal opening, or vent, received intestine and urogenital structures in all vertebrates except placental mammals. Return to BIO 3220 Homepage.