Stereocidaris hemigranosus sea urchin fossil on display at the Smithsonian National Museum of Natural History in Washington, DC.  The fos...

On the right is a Macrocrinus mundulus crinoid with its stem, calyx and anal tube intact.  The fossil on the left is an intact blastoid ...

After roaming the exhibits of the Smithsonian National Museum of Natural History I found a darkened case that contained fossils that I h...