Protoceras; extinct genus of Artiodactyla; endemic to North America from the Oligocene through Miocene periods. Colour printed (chromolithograph) illustration by Heinrich Harder from 鈥楾iere der Urwelt' Animals of the Prehistoric World; 1916; Hamburg. Heinrich Harder (1858-1935) was a German landscape artist and book illustrator. From a series of prehistoric creature cards published by the Reichardt Cocoa company. Natural historian Wilhelm Bolsche wrote the descriptive text.