Sea urchin tube feet
Ever wonder how sea urchins move? They have neat “tube feet” around their entire body, which extend using a water vascular system and have ends that attach to surfaces. The S. purpuratus urchins I work with are really good at attaching to surfaces, so whenever I move them, they leave lots of tube foot endings. So, of course, I took some pictures of the remnant feet under a microscope (each image is at a different depth, since these are 3-D entities).