J__ ^ ^ _ — — 
2 PREFACE TO THE FIRST EDITION. 
I was necessitated then, — and the task occupied considerable time, — I was com- 
pelled to make anatomy and zoology, dissection and classification, proceed beforehand ; '*j 
to seek, in my first remarks on organization, for better principles of distribution ; ' ; 
to employ these, in order to arrive at new remarks ; and in their turn the latter, to i 
carry the principles of distribution to perfection : in fine, to elicit from the mutual 
reaction of the two sciences upon each other, a system of zoology adapted to serve as 
an introduction and a guide in anatomical researches, and a body of anatomical doctrine 
fitted to develope and explain the zoological system. 
The first results of this double labour appeared in 1795, in a special memoir upon a ' 
new division of the white-blooded animals. A sketch of their application to genera, 
and to the division of these into sub-genera, formed the object of my Tableau 
Elementaire des Animaux, printed in 1798, and I improved this work, with the assistance 
of M. Dumeril, in the tables annexed to the first volume of my Lecons d’ Anatomie 
Comparee, in 1800. 
I should, perhaps, have contented myself with perfecting these tables, and proceeded 
immediately to the publication of my great work on anatomy, if, in the course of my ^ 
researches, I had not been frequently struck with another defect of the greater number 
of the general or partial systems of zoology ; I mean, the confusion in which the want 
of critical precision had left a vast number of species, and even many genera. 
Not only were the classes and orders not sufficiently conformed to the intrinsical 
nature of animals, to serve conveniently as the basis to a treatise on comparative 
anatomy, but the genera themselves, though ordinarily better constituted, offered but 
inadequate resources in their nomenclature, on account of the species not having 
been arranged under each of them, conformably to their characters. Thus, in placing 
the Manati in the genus Morse, the Siren in that of the Eels, Gmelin had rendered any 
general proposition relative to the organization of these genera impossible ; just as by 
approximating in the same class and in the same order, and placing side by side, the 
Cuttle and the fresh-water Polypus, he had made it impossible to predicate anything 
generally of the class and order which comprised such incongruous beings. 
I select the above examples from among the most prominent ; but there existed 
an infinitude of such mistakes, less obvious at the first glance, which occasioned incon- 
veniences not less real. 
It was not sufficient, then, to have imagined a new distribution of the classes and 
orders, and to have properly placed the genera ; it was also necessary to examine all 
the species, in order to be assured that they really belonged to the genera in which ; 
they had been placed. i 
Having come to this, I found not only species grouped or dispersed contrary to all rea- | 
son, but I remarked that many had not been established in a positive manner, either | 
by the characters which had been assigned to them, or by their figures and descriptions. 
Here one of them, by means of synonymes, represents several under a single name, 
and often so different that they should not rank in the same genus : there a single 
one is doubled, tripled, and successively reappears in several sub-genera, genera, and 
sometimes different orders. 
What can be said, for example, of the TrichecJius manatus of Gmelin, which, under 
a single specific name, comprehends three species and two genera, — two genera differing 
in almost everything ? By what name shall we speak of the Velella, which figures 
