A new phase in the history of racial thought was inaugurated in the chronologically convenient year of 1800 by Georges Cuvier when he submitted a memorandum for a French expedition to the Pacific, advising on ‘the researches to be carried out relative to the anatomical differences between the diverse races of man’ (Stocking, 1968: 13–41). Cuvier's career prospered and under Napoleon he became one of the dominant figures in French science.

Cuvier was a Protestant who accepted the Biblical story of man's common descent but did not believe that Genesis provided a complete chronology. He took up the questions of Creation and classification in a more open-minded manner than his predecessors, believing that a scientist should concentrate on problems where sufficient evidence was available or could be accumulated, and should not concern himself with those that were for the time being beyond reach. Within zoology Cuvier continued Linnaeus' work by compiling a magisterial study of the animal kingdom. He distinguished four principal branches within this kingdom, the vertebrates, molluscs, articulates and zoophytes, which were further divided into genera and subgenera. Cuvier put great reliance on the concept of biological type, believing that if that had been grasped the essentials of the category could be understood. He emphasised the importance of type in opposition to those who considered that the various forms shaded imperceptibly into one another. Genera and species were both discrete, morphologically stable units, and therefore examples of types. In his extensive study of fishes each volume deals with one genus and the first chapter is devoted to a description of the specimen chosen to represent the type.