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

Derived forms: vitelline sacs

Type of: sac

• Carolina wren
• Carolinas
• Caroline
• Caroline Islands
• caroling
• Carolingian
• Carolingian dynasty
• Carolinian
• caroller
• carolling
• Carolus
• Carolus Linnaeus
• carom
• carotene
• carotenemia
• carotenoid
• Carothers
• carotid
• carotid artery
• carotid body
• carotid plexus
• carotidal
• carotin
• carousal
• carouse