The followers of Linnæus are divided into two classes, explorers and compilers. To the first class belonged his own students and others who ransacked all lands for species to be added to the lists of the "Systema Naturæ." Those men, mostly Scandinavian and Dutch, worked with wonderful zeal, enduring every hardship and making great contributions to knowledge, which they published in more or less satisfactory forms. To these men we owe the beginnings of the science of geographical distribution. Among the most notable of these are Pehr Osbeck and Fredrik Hasselquist, already noted; Otto Fabricius (1744-1822), author of an excellent "Fauna of Greenland"; Carl Peter Thunberg (1743-), successor of Linnæus as rector of the University of Upsala, who collected fishes about Nagasaki, intrusting most of the descriptive work to the less skillful hands of his students, Jonas Nicolas Ahl and Martin Houttuyn; Martin Th. Brünnich, who collected at Marseilles the materials for his "Pisces Massiliensis"; Petrus Forskål (1736-63), whose work on the fishes of the Red Sea ("Descriptio Animalium," etc.), published posthumously in 1775, is one of the most accurate of faunal lists, and one which shows a fine feeling for taxonomic distinctions scarcely traceable in any previous author. Georg Wilhelm Steller (1709-45), naturalist of Bering's expedition, gathered amid incredible hardships the first knowledge of the fishes of Alaska and Siberia, his notes being printed after his tragic death, by Pallas and Krascheninnikov. Petrus Simon Pallas (1741-1811) gives the account of his travels in the North Pacific in his most valuable volumes, "Zoographia Russo-Asiatica"; Johann Georg Gmelin (1709-55) with Samuel Theophilus Gmelin (1745-84), and Johann Anton Güldenstädt (1745-91), like Steller, crossed Siberia, recording its animals. Johann David Schöpf (1752-1800), a Hessian surgeon stationed at Long Island in the Revolutionary War, gave an excellent account of the fishes about New York. Still other naturalists accompanied navigators around the globe, collecting specimens and information as opportunity offered. John Reinhold Forster (1729-98), with his son, John George Adam Forster (1754-94), and Daniel Solander (1736-81), a student of Linnæus, and Sir Joseph Banks (1743-1820), sailed with Captain James Cook. Philibert Commerson (1727-73) accompanied the explorer, Louis Antoine de Bougainville, and furnished nearly all the original material used by Lacépède. Other noted travelers of the early days were Pierre Sonnerat and Mungo Park. Still other naturalists, scarcely less useful, gave detailed accounts of the fauna of their own native regions. Ablest of these was Anatole Risso, an apothecary of Nice, who published in 1810 the "Ichthyologie de Nice," an excellent work, afterward (1826) expanded by him into a "Histoire Naturelle de l'Europe Méridionalé."