The Echinoid Directory
Pronucleolites orbicularis (Phillips); Lower Cornbrash (Bathonian), Middle Jurassic, Scarborough and Northhampton, England. Apical disc plating and phyllode plating. From Barras, C. G. 2006. British Jurassic irregular echinoids. Monograph of the Palaeontographical Society no. 625 (part of volume 159 for 2005), 1-168, pls 1-14.