More Anatomy

Many sperm whales stranded on beaches or caught by whalers exhibit telltale circular scars like these. Only one thing could have made them: the strong suckers that line the giant squid’s eight arms...
Comb jellies (such as this Bolinopsis species) are named for their combs: the rows of cilia lining their bodies that propel them through the ocean. Read more about jellyfish and comb jellies .
In the X-ray image of this Viper Moray Eel ( Enchelynassa canina ), note the second set of jaws in the “throat”; these are the gill arches, which are present in all fish. Gill arches support the...
The clearly pictured spines, rays and snout make identifying this longnose butterflyfish ( Forcipiger longirostris ), which was collected in French Polynesia in 2004, straightforward in this X-ray...
This image from a scanning electron micrograph magnifies the tiny teeth that cover the surface of the giant squid’s tongue-like organ, or radula . Seven rows of sharp teeth help direct tiny pieces of...
The feathery strands at the back of this nudibranch’s ( Chromodoris willani ) body are no mere adornment: they’re its gills! Nudibranchs, shell-less snails or sea slugs, are named for these tufted...
Hundreds of powerful suckers stud the flattened club at the end of the giant squid’s long feeding tentacle. They help the squid capture and hang on tightly to its prey. They also leave deep scars in...
A mass of white muscle the size of a softball surrounds the dark brown beak of a giant squid. Learn more about this animal's oversized anatomy in our Giant Squid section .
Tropical hatchetfish ( Argyropelecus lychnus ), like the one shown in this X-ray photograph, live in the dark depths of the ocean ; this specimen was collected at about 2,789 feet (850 meters) in the...
Scientists in the Division of Fishes at the Smithsonian's National Museum of Natural History use X-ray imaging to study the complex bone structure and diversity of fish. This image gallery showcases...
Giant squid have the largest eye in the animal kingdom. At up to 10 inches in diameter, people often describe it as the size of a dinner plate -- or, in other words, as big as a human head. Here,...
This close-up photo shows the tough, serrated ring around the opening of a giant squid sucker. The ring is made of chitin—the same material that’s in your fingernails. Using suction, the sucker...
The elongated body, characteristic long and narrow snout, and small teeth make the slender snipe eel ( Nemichthys scolopaceus ) easily identifiable in this X-ray image. Snipe eels live at great...
These are fossil remains of archaeocetes, ancient whales, from the Paracas Formation of Peru's Pisco Basin . Smithsonian paleobiologist Nicholas D. Pyenson and a team of scientists discovered the...
Like octopods and cuttlefishes, giant squid have eight arms. But they use their two much longer feeding tentacles to seize prey. The tentacles have powerful suckers at the ends. More about the giant...
This common octopus ( Octopus vulgaris ) doesn't have a jetpack to help him zoom through the water, but he's got something pretty close: a siphon that shoots water. (It's the little orange/yellow cup...
The distinctive form of a winghead shark ( Eusphyra blochii ) is revealed by an X-ray image. The Winghead Shark, one of about ten species of hammerhead sharks, has its eyes set at the tips of its...
An X-ray image of a Monterey skate ( Raja montereyensis ) reveals a spine that extends like a tail out from the pelvic fin. The skeletons of skates, rays, chimaeras, and sharks are made of cartilage...
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