PREFACE TO THE FIRST EDITION. XVII 



To anticipate a remark which will naturally present itself 

 to many, I must observe that I have neither desired nor pre- 

 tended to class animals so as to form one single line, or so as 

 to mark their relative superiority. I even consider every at- 

 tempt of this kind impracticable. Thus, I do not mean that 

 the Mammalia or Birds which come last, are the most imper- 

 fect of their class ; still less do I believe that the last of the 

 Mammalia are more perfect than the first of the Birds, the 

 last of the Mollusca more so than the first of the Annulata or 

 of the Radiata, even restraining the meaning of this vague 

 word perfect to that of most completely organized. I re- 

 gard my divisions and subdivisions as the merely graduated 

 expression of the resemblance of the beings which enter into 

 each of them, and although in some we observe a sort of de- 

 gra'dation or passage from one species to the other, which can- 

 not be denied, this disposition is far from being general. The 

 pretended chain of beings, as applied to the whole creation, 

 is but an erroneous application of those partial observations, 

 which are only true when confined to the limits within which 

 they were made it has, in my opinion, proved more detri- 

 mental to the progress of natural history in modern times, 

 than it is easy to imagine. 



It is in conformity with these views that I have established 

 my four general divisions, which have already been made 

 known in a separate Memoir. I still think it expresses the 

 real relations of animals more exactly than the old arrange- 

 ment of Vertebrata and Invertebrata, for the simple reason, 

 that the former animals have a much greater resemblance to 

 each other than to the latter, and that it was necessary to 

 mark this difference in the extent of their relations. 



M. Virey, in an article of the " Nouveau Dictionnaire d'His- 

 toire Naturelle,'' had already discovered a part of the basis of 

 this division, and principally that which reposes on the ner- 

 vous system. 



The particular approximation of oviparous Vertebrata, in- 

 ter se, originated from the curious observations of M. Geoff"- 

 roy on the composition of bony heads ; and from those I have 

 Vol. I.~(3) 



