Holotype of Exiteloceras jenneyi (USNM 12295). Original unmodified images provided by courtesy of the Smithsonian NMNH and adapted and presented here under a Creative Commons BY-NC 4.0 license (NMNH GUID http://n2t.net/ark:/65665/377c0bdaf-00c4-4afc-86a0-3924694a87af). Exiteloceras jenneyi from the Maastrichtian Pierre Shale Fm. of Niobrara County, Wyoming (YPM 32685).