1. Membranous structure that functions as the circulatory system in mammalian embryos until the heart becomes functional
   - yolk sac, vitelline sac, umbilical vesicle

Type of: sac

• Myrcia
• Myrciaria
• Myrciaria cauliflora
• Myrdal
• myriad
• myriagram
• myriameter
• myriametre
• myriapod
• Myriapoda
• Myrica
• Myrica cerifera
• Myrica gale
• Myrica pensylvanica
• Myricaceae
• Myricales
• Myricaria
• Myricaria germanica
• myringa
• myringectomy
• myringoplasty
• myringotomy
• Myriophyllum
• myristic acid
• Myristica