The Sea Raiders sea monsters include Scylla and Charybdis of Greek mythology, and the kraken of medieval times which is thought to have been a giant squid. Previous fictional encounters with giant squids are described in chapter 59 of Herman Melville's "Moby-Dick" of 1851, and in Jules Verne's "Twenty Thousand Leagues Under the Sea" of 1870. The narrator describes a recent period when a new sort of giant squid, a species named "Haploteuthis ferox", became known. (This fictitious name can be compared with the genus name "Architeuthis" of the giant squid.) As a part of the survey of the period, including early encounters
Twenty Thousand Leagues Under the Sea not to a "depth", as 20,000 leagues (80,000 km) is nearly twice the circumference of the Earth. The greatest depth mentioned in the book is four leagues. The book uses metric leagues, which are four kilometres each. During the year 1866, ships of several nations spot a mysterious sea monster, which some suggest to be a giant narwhal. The United States government assembles an expedition in New York City to find and destroy the monster. Professor Pierre Aronnax, a French marine biologist and narrator of the story, who happens to be in New York at the time, receives a last-minute