308 ESSAY ON CLASSIFICATION. 



not to speak of the lowest animals, which, from want of 

 knowledge of their internal structure, still remain in great 

 confusion. In this rapid sketch of the farther subdivi- 

 sions which the Classes Insecta and Worms of Linnaeus 

 have undergone under the influence of Cuvier, I have not, 

 of course, alluded to the important contributions made to 

 our knowledge of isolated classes by special writers, but 

 limited my remarks to the works of those naturalists who 

 have considered the subject upon the most extensive 

 scale. 



Thus far no attempt had been made to combine the 

 classes among themselves into more comprehensive divi- 

 sions, under a higher point of view, beyond that of divid- 

 ing the whole animal kingdom into Vertebrata and Inver- 

 tebrata, a division which corresponds to that of Aristotle, 

 into tya Ivaipa and &a avaijjia. All efforts were rather 

 directed towards establishing a natural series, from the 

 lowest Infusoria up to Man; which, with many, soon be- 

 came a favourite tendency, and ended in being presented 

 as a scientific doctrine by Blainville. 



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 results of 

 his investigations upon the more intimate relations of 

 certain classes of the animal kingdom to one another, 1 

 which had satisfied him that all animals are constructed 

 upon four different plans, or, as it were, cast in four dif- 



1 Ann. clu Museum d'Histoire Naturelle, vol. xix; Paris, 1812. 



