Stock Photo: The Atlantic horseshoe crab (Limulus polyphemus) is a marine chelicerate arthropod. . . Colour printed illustration by Heinrich Harder from "Tiere 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.