Earliest of those is Antoine Gouan, whose "Historia Piscium" was published in Paris in 1770. In this work, which is of fair quality, only genera were included, and the three new ones which he introduces into the "System" (_Lepadogaster_, _Lepidopus_, and _Trachypterus_) are still retained with his definition of them. Johann Friedrich Gmelin (1748-1804), a relative of the explorers of Siberia, published in 1788 a thirteenth edition of the "Systema Naturæ" of Linnæus, adding to it the discoveries of Forskål, Forster, and others who had written since Linnæus' time. This work was useful as bringing the compilation of Linnæus to a later date, but it is not well done, the compiler having little knowledge of the animals described and little penetration in matters of taxonomy. Very similar in character, although more lucid in expression, is the French compilation of the same date (1788), "Tableau Encyclopédique et Méthodique des Trois Règnes de la Nature," by the Abbé J. P. Bonnaterre. Another volume of the "Encyclopédie Méthodique," of still less merit, was published as a dictionary in Paris in 1787 by Réné Just Haüy. Another dictionary in 1817 even poorer was the work of Hippolyte Cloquet. In 1792, Johann Julius Walbaum (1721-1800), a German compiler of a little higher rank, gathered together the records of all known species, using the work of Artedi as a basis and giving binominal names in place of the vernacular terms used by Schöpf, Steller, Pennant, and Krascheninnikov. Far more pretentious and more generally useful, as well as containing a large amount of original material, is the "Ichthyologia" of Mark Eliezer Bloch, published in Berlin in various parts from 1782 to 1785. It was originally in German and divided into two portions--"Oeconomische Naturgeschichte der Fische Deutschlands" and "Naturgeschichte der auslandischen Fische." Bloch was a Jewish physician, born at Anspach in 1723, and at the age of fifty-six began to devote himself to ichthyology. In his great work is contained every species which he had himself seen, every one which he could purchase from collections, and every one of which he could find drawings made by others. That part which relates to the fishes of Germany is admirably done. In the treatment of East Indian and American fishes there is much guesswork and many errors of description and of fact, for which the author was not directly responsible. To learn to interpret the personal equation in the systematic work of other men is one of the most delicate of taxonomic arts. After the publication of these great folio volumes of plates, Dr. Bloch began a systematic catalogue to include all known species. This was published after his death by his collaborator, the philologist, Dr. Johann Gottlob Schneider. This work, "M. E. Blochii Systema Ichthyologia," contains 1519 species of fishes, and is the most creditable compilation subsequent to the death of Linnæus.