-PREFACE TO THE FIRST EDITION. XVil 
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- 
gradation 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 
Vor. I.—(3) 
