After Aristotle, no epoch-making zoölogist arose until Linné was born. In England Linné was preceded by Ray, but binomial nomenclature and the first genuine attempt at the classification of animals dates back to the _Systema Naturæ_ of Linné, the tenth edition of which appeared in 1758. [Illustration: PORTRAIT OF LAMARCK] The contemporaries of Lamarck in biological science, in the eighteenth century, were Camper (1722-89), Spallanzani (1729-99), Wolff (1733-94), Hunter (1728-93), Bichat (1771-1802), and Vicq d'Azyr (1748-94). These were all anatomists and physiologists, the last-named being the first to propose and use the term "comparative anatomy," while Bichat was the founder of histology and pathological anatomy. There was in fact no prominent systematic zoölogist in the interval between Linné and Lamarck. In France there were only two zoölogists of prominence when Lamarck assumed his duties at the Museum. These were Bruguière the conchologist and Olivier the entomologist. In Germany Hermann was the leading systematic zoölogist. We would not forget the labors of the great German anatomist and physiologist Blumenbach, who was also the founder of anthropology; nor the German anatomists Tiedemann, Bojanus, and Carus; nor the embryologist Döllinger. But Lamarck's method and point of view were of a new order--he was much more than a mere systematist. His work in systematic zoölogy, unlike that of Linné, and especially of Cuvier, was that of a far higher grade. Lamarck, besides his rigid, analytical, thorough, and comprehensive work on the invertebrates, whereby he evolved order and system out of the chaotic mass of forms comprised in the Insects and Vermes of Linné, was animated with conceptions and theories to which his forerunners and contemporaries, Geoffroy St. Hilaire excepted, were entire strangers. His tabular view of the classes of the animal kingdom was to his mind a genealogical tree; his idea of the animal kingdom anticipated and was akin to that of our day. He compares the animal series to a tree with its numerous branches, rather than to a single chain of being. This series, as he expressly states, began with the monad and ended with man; it began with the simple and ended with the complex, or, as we should now say, it proceeded from the generalized or undifferentiated to the specialized and differentiated. He perceived that many forms had been subjected to what he calls degeneration, or, as we say, modification, and that the progress from the simple to the complex was by no means direct. Moreover, fossil animals were, according to his views, practically extinct species, and stood in the light of being the ancestors of the members of our existing fauna. In fact, his views, notwithstanding shortcomings and errors in classification naturally due to the limited knowledge of anatomy and development of his time, have been at the end of a century entirely confirmed--a striking testimony to