These delicate X-rays were made by a Smithsonian scientist for research purposes but tell a stunningly visual story of evolution and diversity. The photographs will be on display at the National Museum of Natural History until Aug. 5.

An X-ray of a hammerhead shark, or Eusphyra blochii, on exhibit at the National Museum of Natural Science. “X-ray Vision: Fish Inside Out,” organized by the Smithsonian’s National Museum of Natural History and the Smithsonian Institution Traveling Exhibition Service, is an exhibit traveling to museums across the country through 2015. Sandra J. Raredon/Division of Fishes, NMNH