Caption:
Sea urchins and their spines. Slate pencil urchin, Heterocentrotus mamillatus, Echinus mammillaris 8, long-spined urchin, Diadema setosum, Echinus setosa 10, cake urchins, Clypeaster species 12-17. Handcoloured copperplate drawn and engraved by Georg Wolfgang Knorr from his Deliciae Naturae Selectae of Kabinet van Zeldzaamheden der Natuur, Blusse and Son, Nuremberg, 1771. Specimens from a Wunderkammer or Cabinet of Curiosities of Johann Ambrosius Beurer.