PREFACE TO THE FIRST EDITION. 3 
twice among the Medusa and once among the Holothuria ? How are we to reassemble 
the Bijjhora, of which some are there called Dagysa, the greater number Salpa, while 
several are ranged among the Holothurice ? 
It did not therefore suffice, in order completely to attain the object aimed at, to 
review the species : it was necessary to examine their synonymes ; or, in other words, 
to re- model the system of animals. 
Such an enterprize, from the prodigious developement of the science of late years, 
could not have been executed completely by any one individual, even granting him 
the longest life, and no other occupation. Had I been constrained to depend upon 
myself alone, I should not have been able to prepare even the simple sketch which 
I now give ; but the resources of my position seemed to me to supply what I 
wanted both of time and talent. Living in the midst of so many able naturalists, 
drawing from their works as fast as they appeared, freely enjoying the use of the 
collections they had made, and having myself formed a very considerable one, ex- 
pressly appropriated to my object, a great part of my labour consisted merely in the 
employment of so many rich materials. It was not possible, for instance, that much 
remained for me to do on shells, studied by M. de Lamarck, nor on quadrupeds, described 
by M. GeofFroy. The numerous and new affinities described by M. de Lacepede, were 
so many data for my system of fishes. M. Levaillant, among so many beautiful birds 
collected from all parts, perceived details of organization which I immediately adapted 
to my plan. My own researches, employed and fructified by other naturalists, yielded 
results to me which, in my hands alone, they would not all have produced. So, also, 
M. de Blainville and M. Oppel, in examining the cabinet which I had formed of 
anatomical preparations on which I designed to found my divisions of reptiles, anti- 
cipated — and perhaps better than I should have done — results of which as yet I had 
but a glimpse, &c., &c. 
Encouraged by these reflections, I determined to precede my Treatise on Com- 
parative Anatomy by a kind of abridged system of animals, in which I should present 
their divisions and subdivisions of all degrees, established in a parallel manner upon 
their structure, both internal and external ; where I would give the indication of well- 
authenticated species that belonged, with certainty, to each of the subdivisions ; and 
where, to create more interest, I would enter into some details upon such of the 
species as, from their abundance in our country, the services which they render 
us, the damage which they occasion to us, the singularity of their manners and economy, 
their extraordinary forms, their beauty, or their magnitude, are the most remarkable. 
I hoped by so doing to prove useful to young naturalists, who, for the most part, 
have but little idea of the confusion and errors of criticism in which the most accredited 
works abound, and who, particularly in foreign countries, do not sufficiently attend to 
the study of the true relations of the conformation of beings : I considered myself as 
rendering a more direct service to those anatomists, who require to know beforehand 
to which orders they should direct their researches, when they wish to solve by com- 
parative anatomy some problem of human anatomy or physiology, but whose ordinary 
occupations do not sufficiently prepare them for fulfilling this condition, which is essen- 
tial to their success. 
Nevertheless, I have not professed to extend this twofold view equally to all classes 
of the animal kingdom ; and the vertebrated animals, as in every sense the most in- 
B 2 
