PERIOD OF CUVIER. 309 



ferent moulds. A more suggestive view of the subject 

 never was presented before to the appreciation of investi- 

 gators ; and, though it has as yet by no means produced 

 all the results which certainly must flow from its further 

 consideration, it has already led to the most unquestion- 

 able improvements which classification in general has 

 made since the days of Aristotle ; and, if I am not greatly 

 mistaken, it is only so far as that fundamental prin- 

 ciple has been adhered to that the changes proposed in 

 our systems by later writers have proved a real progress, 

 and not so many retrograde 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 principes 

 que nous venons de poser, en se debarrassant des pre- 

 juges etablis sur les divisions anciennenient admises, en 

 n'ayant egard qu'a reorganisation et a la nature des ani- 

 maux, 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 generaux, si Ton 

 peut s'exprimer ainsi, d'apres lesquels tous les animaux 

 semblent avoir ete modeles et dont les divisions ulteri- 

 eures, de quelque titre que les naturalistes les aient de- 

 corees, ne sont que des modifications assez legeres, fondees 

 sur le developpement ou I'addition de quelques parties, 

 qui ne changent rien a 1'essence du plan." 



It is therefore incredible to me how, in presence of 

 such explicit expressions, Cuvier can be represented, as 

 he still is occasionally, as favouring a division of the ani- 

 mal kingdom into Vertebrata and Invertebrata. 1 Cuvier, 



1 EHRENBERG (C. G.), Die Corallenthiere des rothen Meeres ; Berlin, 1834, 

 4to., p. 30, note. 



