A 17th century ilIllustration of a narwhal

Illustration of a "fish with horny snout" from a Dutch edition of Kircher's Mundus subterraneus (De Onderaardse Wereld). The fifth chapter of this book, which starts on the verso of this sheet, discusses horns and investigates the possible existence of unicorns. The author reasons that known examples of long horns, in the possession of nobility or church, could not possibly come from land animals but rather originated from sea animals. Inhabitants of Greenland would have told explorers about fish with horns for snouts protecting them from whales. The illustration is made after a description of such a "fish".