More Anatomy

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...
Inside the giant squid's sharp beak is a tongue-like organ called the radula (shown in yellow). Covered with rows of tiny teeth, it rams bite size pieces of food down the squid's throat. The pieces...
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...
A right whale opens its mouth wide, revealing huge plates of baleen hanging from its upper jaw. There are between 200 and 270 baleen plates on each side of a right whale's upper jaw. They work like a...
The Palauan primitive cave eel ( Protanguilla palau ) has an evolutionary history that dates back some 200 million years . Because of this and the fact that it has retained some primitive features,...
The robust oval, spine covered body of a long-spined porcupine fish ( Diodon holocanthus ) is revealed in this X-ray image. To ward off predators, a porcupinefish inflates its body by pumping water...
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...
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...
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...
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...
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...
Dr. Clyde Roper discusses the fascinating anatomy of the giant squid ( Architeuthis dux) in this excerpt of "Eyeball to Eyeball," an episode of Errol Morris' First Person television series. Watch...
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...
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...
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...
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 .
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