The Smithsonian's National Museum of Natural History in D.C. gives visitors an "inside" look at fish with its visiting exhibit, X-Ray Vision: Fish Inside and Out.
Already, the Smithsonian's National Collection of Fishes amounted to the largest representation of fish specimen, with more than 70 percent of the world's species. Sometimes called the "fish library," the Smithsonian houses the 6.2 million specimens in its Museum Support Center.
While some species are represented by only one specimen, others are represented by males, females, larvae and eggs. The oldest of the collection dates back to the 1800s.
The x-ray exhibit was developed by the Smithsonian Institution Traveling Exhibit Service (SITES) and will travel to other venues following its time at the Museum of Natural History.
"The exhibit was produced by the Smithsonian and it features images that were made as part of the ongoing research projects at the National Museum of Natural History. Plus, the images are beautiful as well as informative. It was only natural that the exhibit be at the Smithsonian as part of its tour," Lynne Parenti, the curator of the exhibition wrote, in an email to The News-Letter.
Tucked in the back of the rooms devoted to aquatic and marine displays, X-Ray Vision fills a small room that makes economical use of its wall space. The majority of the exhibit are framed x-rays, though in the center are vials of preserved specimen.
These specimen serve as a focal point to the exhibit and also as a method of drawing people in, especially with the stark subject contrasting against the bold blue background of the room. Each x-ray is described with particular attention to the specimen, its discovery date, and often how the organism factors into the marine ecosystem.
The x-rays allow visitors to examine the specimen through black-and-white radiographs. This method of study prevents any cutting or other dissection that may alter the specimen. It also allows various specimens to be displayed in great detail, allowing focus on bone structure and diversity between the species. For specimen like the Monterey skate, or Raja montereyensis, the x-ray reveals the cartilage skeleton that exists in skates, rays, chimaeras and sharks.
Moreover, X-rays can also show any undigested food in the guts of the fish, allowing ichthyologists to understand the fish's role in relation to other critters in the environment.
The exhibit also includes a focus on the collection process and method of studying, including the x-ray process itself. Wilhelm Rontgen is credited with the discovery of x-radiation and took the first medical x-ray, which happened to be of his wife's hand, in December 1895. Scientists have since used this technique to study organisms or minerals in rock, and even far away stars.
The x-rays of 40 specimens are displayed, each explained by a panel that discusses the specimen as it relates to the environment, science or other fish species. For example, Dhiho's Seahorse measures a little over an inch, but the x-ray allows viewers to note features such as its characteristic head and tail at much greater detail.
The images are arranged in evolutionary sequence so one may examine the physiological changes throughout time. Visitors may simply examine the x-ray to note details such as the number of vertebrae or the placement of fins. However, the exhibit also features the conclusions scientists have drawn from studying these x-rays.
To better compare the fishes, radiographers limit each X-ray frame to one fish and made sure every fish faced the left. However, some specimen are captured in group shots to facilitate group comparison.
The winghead shark, or eusphyra blochii, is a T-shaped fish that one might recognize to be a hammerhead shark. Its eyes are set at the tips of its head, which scientists think allows it to have a greater field of view.
Amidst the other permanent displays in the museum, the x-ray exhibition features a unique combination of art and science. "The naturally beautiful x-rays were produced as part of research projects by Smithsonian scientists. The 40 images represent the evolution of fishes, from the primitive sharks and rays through to the spiny-finned perches and their relatives," Parenti wrote.
Public response has been positive and Parenti is enthusiastic that the mission of the exhibition is reaching a sizable audience. "The exhibit conveys the idea that we conduct research on the comparative morphology of fishes at the Smithsonian," Parenti wrote.
The X-Ray Vision exhibit will remain on display until Aug. 5, 2012.
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