GUSTOIMAGES / SCIENCE PHOTO LIBRARY GUSTOIMAGES / SCIENCE PHOTO LIBRARY
Bird egg and embryo. X-ray of an egg with an 18-day-old bird embryo developing inside. This is a well-developed embryo near full term. The X-ray shows the bones of its skeleton, with the skull at upper left, the backbone at lower left, and the wing and leg bones at centre and right. Typical incubation periods for eggs such as those laid by chickens are around 20 days, though in other species the incubation period can range from 10 to 45 days.
Model release not required. Property release not required.