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Rh The enumeration of orders above given will enable the reader to form some conception of the progress of knowledge relating to the lower forms of life during the fifty odd years which intervened between Linnaeus and Lamarck. The number of genera recognized by Lamarck is more than ten times as great as that recorded by Linnaeus.

We have mentioned Lamarck before his great contemporary Cuvier because, in spite of his valuable philosophical doctrine of development, he was, as compared with Cuvier and estimated as a systematic zoologist, a mere enlargement and logical outcome of Linnaeus.

The distinctive merit of G. L. Cuvier (1769–1832) is that he started a new view as to the relationship of animals, which he may be said in a large measure to have demonstrated as true by his own anatomical researches. He opposed the scala naturae theory, and recognized four distinct and divergent branches or embranchemens, as he called them, in each of which he arranged a certain number of the Linnaean classes, or similar classes. The embranchemens were characterized each by a different type of anatomical structure. Cuvier thus laid the foundation of that branching tree-like arrangement of the classes and orders of animals now recognized as being the necessary result of attempts to represent what is practically a genealogical tree or pedigree. Apart from this, Cuvier was a keen-sighted and enthusiastic anatomist of great skill and industry. It is astonishing how many good observers it requires to dissect and draw and record over and over again the structure of an animal before an approximately correct account of it is obtained. Cuvier dissected many Molluscs and other animals which had not previously been anatomized; of others he gave more correct accounts than had been given by earlier writers. Another special distinction of Cuvier is his remarkable work in comparing extinct with recent organisms, his descriptions of the fossil Mammalia of the Paris basin, and his general application of the knowledge of recent animals to the reconstruction of extinct ones, as indicated by fragments only of their skeletons. It was in 1812 that Cuvier communicated to the Academy of Sciences of Paris his views on the classification of animals. He says:—

“Si l’on considered le règne animal d’après les principles que nous venons de poser, en se debarassant des préjuges établis sur les divisions anciennement admises, en n'ayant égard qu’ à l’organisation et à la nature des animaux, et non pas à leur grandeur, à leur utilité, au plus on moins de connaissance que nous en avons, ni à toutes les autres circonstances accessoires, on trouvera qu’il existe quatre formes principales, quatre plans généraux, si l’on peut s'exprimer ainsi, d’après lesquels tous les animaux semblent avoir été modelés et dont les divisions ultérieures, de quelque titre que les naturalistes les aient décorées, ne sont que des modifications assez légères, fondées sur le développement, on l’addition de quelques parties qui ne changent rien à l’essence du plan.”

His classification as finally elaborated in Le Règne Animal (Paris, 1829) is as follows:—

The leading idea of Cuvier, his four embranchemens, was confirmed by the Russo-German naturalist Von Baer (1792–1876), who adopted Cuvier’s divisions, speaking of them as the peripheric, the longitudinal, the massive, and the vertebrate types of structure. Von Baer, however, has another place in the history of zoology, being the first and most striking figure in the introduction of embryology into the consideration of the relations of animals to one another.

Cuvier may be regarded as the zoologist by whom anatomy was made the one important guide to the understanding of the relations of animals. But the belief, dating from Malpighi (1670), that there is a relationship to be discovered,and not merely a haphazard congregation of varieties ofstructure to be classified, had previously gained ground.Cuvier was farniliar with the speculations of the “Natur-philosophen,” and with the doctrine of transmutation and filiation by which they endeavoured to account for existing animal forms. The noble aim of F. W. J. Schelling, “das ganze System der Naturlehre von dem Gesetze der Schwere bis zu den Bildungstrieben der Organismus als ein organisches Ganze darzustellen,” which has ultimately been realized through Darwin, was a general one among the scientific men of the year 1800. Lamarck accepted the development theory fully, and pushed his speculations far beyond the realm of fact. The more cautious Cuvier adopted a view of the relationships of animals which, whilst denying genetic connexion as the explanation, recognized an essential identity of structure throughout whole groups of animals. This identity was held to be due to an ultimate law of nature or the Creator’s plan. The tracing out of this identity in diversity, whether regarded as evidence of blood-relationship or as a remarkable display of skill on the part of the Creator in varying the details whilst retaining the essential, became at this period a special, pursuit, to which Goethe, the poet, who himself contributed importantly to it, gave the name “morphology.” C. F. Wolff, Goethe and Oken share the credit of having initiated these views, in regard especially to the structure of flowering plants and the Vertebrate skull. Cuvier’s doctrine of four plans of structure was essentially a morphological one, and so was the single-scale doctrine of Buffon and Lamarck, to which it was opposed. Cuvier’s morphological doctrine received its fullest development in the principle of the “correlation of parts,” which he applied to palaeontological investigation, namely, that every animal is a definite whole, and that no part can be varied without entailing correlated and law-abiding variations in other parts, so that from a fragment it should be possible, had we a full knowledge of the laws of animal structure or morphology, to reconstruct the whole. Here Cuvier was imperfectly formulating, without- ecognizing the real physical basis of the phenomena, the results of the laws of heredity, which were subsequently investigated and brought to bear on the problems of animal structure by Darwin.

Sir Richard Owen (1804–1892) may be regarded as the foremost of Cuvier’s disciples. Owen not only occupied himself with the dissection of rare animals, such as the Nautilus, Lingula, Limulus, Protopterus, Apteryx, &c., and with the description and reconstruction of extinct reptiles, birds and Pearlymammals—following the Cuvierian tradition—but gave precision and currency to the morphological doctrines which had taken their rise in the beginning of the century by