X-rays of fish skeletons that scientists use to study evolutionary development are now displayed as art. A new exhibition at the Smithsonian's National Museum of Natural History will feature 40 x-rays of sea creatures laid out in evolutionary sequence. X-Ray Vision: Fish Inside-Out showcases the work of the museum’s scientists. X-rays allow researchers to study fish structures without dissections. The exhibition opens to the public on February 4 and runs until August 5.