27. Knight restores Thespesius (Trachodon), 1901
Frederick Lucas was one of the first American paleontologists to write books for the general public on prehistoric life, including dinosaurs, and his Animals of the Past (1901) and Life Before Man in North America (1902) helped shape the public view of dinosaurs in the early twentieth century. Lucas employed for his principal illustrator the singular Charles Knight, who in his short career had already established himself as the country's premier dinosaur artist.
The animal depicted here by Knight is called by Lucas Thespesius. However, it is the same dinosaur that Marsh had called Claosaurus, and others would shortly identify with Trachodon. Lucas used the name Thespesius because he was convinced that several bones found by Leidy in 1856 were identical to those in Marsh's Claosaurus, and therefore Leidy's name had priority. The nomenclature confusion would get worse. Lucas himself later changed his mind and reverted to Trachodon, but in 1943 that name gave way to Anatosaurus, and today, we consider Knight's subject to be a species of Edmontosaurus.
The work exhibited is a little known paper by Lucas that announced his first book. It contains two other paintings by Knight, of a Triceratops, and a Stegosaurus. For more on the nomenclature problems that arose with the first hadrosaurs, see What's In a Name?
Source
Lucas, Frederick A. "The Dinosaurs or terrible lizards," in: Annual Report of the Board of Regents of the Smithsonian Institution, for the year ending June 30, 1901, pp. 641-647. This work was on display in the original exhibition as item 27.