Chap. III. PERIOD OF CUVIER. 193 



SECTION IV. 



PERIOD OF CUVIER, AND ANATOMICAL SYSTEMS. 



The most important period in the history of Zoology begins, however, with the 

 year 1812, when Cuvier laid before the Academy of Sciences in Paris the residts 

 of his investigations upon the more intimate relations of certain classes of the 

 animal kingdom to one another,' which had satisfied him that all animals are con- 

 structed upon four different plans, or, as it were, cast in four different moulds. 

 A more suggestive view of the subject never was presented before to the appre- 

 ciation of investigators; and, though it has by no means as yet produced all the 

 results which certainly are to flow from its further consideration, it ha.s already led 

 to the most unquestionable improvements which classification in general has made 

 since the days of Aristotle, and, if I am not greatly mistaken, it is only in as 

 far as that fundamental principle has been adhered to that the changes proposed 

 in our systems, by later writers, have proved a real progress, and not as many retro- 

 grade steps. 



This great principle, introduced into our science by Cuvier, is expressed by him 

 in these memorable words: "Si Ton considere le regne animal d'apres les prin- 

 cipes que nous venons de poser, en se debarrassant des prejuges etablis sur les 

 divisions anciennement admises, en n'ayant egard qu'a I'organisation et a la nature 

 des animaux, et non pas a leur grandeur, a leur utilite, au plus ou moins de 

 connaissance que nous en avons, ni a toutes les autres circonstances accessoires, on 

 trouvera qu'il existe quatre formes principales, quatre plans gen^raux, si Ton pent 

 s'exprimer ainsi, d'apres lesquels tous les animaux semblent avoir ete modeles et 

 dont les divisions ulterieures, de quelque titre que les naturalistes les aient deco- 

 rees, ne sont que des modifications assez legeres fondees sur le developpement ou 

 r addition do quelques parties, qui ne changent rien h 1' essence du plan." 



It is therefore incredible to me how, in presence of such explicit expres.sions, 

 Cuvier can be represented, as he is still occasionally, as fiivoring a division of 

 the animal kingdom into Vertebrate and Invertebrata.^ Cuvier, moreover, was the 

 first to recognize practically the inequality of all the divisions he adopts in his 

 system ; and this constitutes further a great and important step, even though he 

 may not have found the correct measure for all his groups. For we must remem- 

 ber that at the time he wrote, naturalists were bent upon establishing one con- 



* Ann. du Museum d'llistoire Naturelle, vol. xix., ' Eiiuexberg, (C. G.,) Die Corallenthiere des 



Paris, 1812. rothen Meercs, Berlin. 1834, 4to., p. 30, note. 



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