A purple-spined sea urchin (Arbacia punctulata) at the Flower Garden Banks National Marine Sanctuary, l ocated 70 to 115 miles off the coast of Texas and Louisiana (NOAA picture).
Fore reef NE of Tareu Pass (Moorea, French Polynesia) from CalPhotos: A database of photos of plants, animals, habitats and other natural history subjects [web application]. BSCIT, University of California, Berkeley. Online at: http://calphotos.berkeley.edu/ used with permission
aboral, oral, lateral views and ambulacrum details from Cotteau, G. H. & Triger, J. 1857-1869. Échinides du département de la Sarthe, considérés au point de vue zoologique et stratigraphique. J.-B. Baillière et Fils, Paris, xv+457 pp.
Tripatagus pittsi Zachos, 2012; MMNS IP-103.1 (paratype). Marianna Limestone, Vicksburg Group, Rupelian, Oligocene of Marquette Cement Company quarry, near Brandon, Mississippi, USA. Apical view. Scale bar equals 10 mm. Image by Louis G. Zachos.