This unidentified sea urchin fossil moved along the seafloor in the Mississippian Period. This fossil is on display on the first floor of the Indiana State Museum as of May 2012. More than likely it was found around Crawfordsville, Indiana. That is a some beautiful 3-D prep work!
Maybe it is a Lepidesthes colletti named by White in 1878. See this specimen at the The Natural History Museum web site.
Learn more about the Indiana State Museum at their web site.