Protosaurus [Protorosaurus] speneri from Das Buch der Geologie. Naturgeschichte der Erde in allgemein verständlicher Darstellung für alle Freunde dieser Wissenschaft [The Book of Geology: The Natural History of the Earth in a Generally Understandable Presentation for All Friends of the Science] by Rudolph Ludwig (1861, Otto Spamer Publishing House, Leipzig), volume II.
https://babel.hathitrust.org/cgi/pt?id=uc1.b4349889&seq=355&view=1up









