More Anatomy

An X-ray image of grooved razorfish ( Centriscus scutatus ). Razorfish are encased in thin, transparent bony plates attached to their spines, which you can see in the X-ray. Also known as shrimpfish...
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 .
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...
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...
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...
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...
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...
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...
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...
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...
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...
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...
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,...
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...
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...
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...
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 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,...
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