xX PREFACE TO THE FIRST EDITION. 
every thing? By what name shall we speak of the Velella, 
which figures there twice among the Medusz and once among 
the Holothurie ? How are we to bring together the Biphore ; 
some of which are called there Dagyse, the greater number 
Salpe, and several placed among the Holothuriz. 
In order, therefore, completely to attain the object, it was 
not suflicient to review the species—it was necessary to re- 
view their synonymes, or in other words to remodel the sys- 
tem of animals. 
Such an enterprise, from the prodigious development of 
the science in late years, could not have been executed com- 
pletely by any one individual, even supposing him to have no 
other employment and to live the longest possible term of 
years; had I been constrained to depend upon myself alone, 
I should not have been able to prepare even the simple sketch 
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—enjoying the use of their collec- 
tions as freely as themselves—and having formed a very con- 
siderable one myself especially appropriated to my object; a 
great portion of my labour consisted merely in the employ- 
ment of so many rich materials. It was not possible, for in- 
stance, that much remained for me to do on shells studied by 
M. de Lamarck, or on quadrupeds described by M. Geoffroy. 
The numerous and new aflinities observed by M. de Lace- 
pede were so many traits for my system of fishes. Among so 
many beautiful birds, collected from all parts of the world, 
M. Le Vaillant perceived details of organization, which I im- 
mediately adapted to my plan. My own researches, employed 
and multiplied by other naturalists, yielded those fruits to me, 
which, in my hands alone, they would not, all, have produced. 
Thus, by examining, in the cabinet I have formed, the ana- 
tomical preparations on which I designed to found my division 
of reptiles, M. de Blainville and M. Oppel anticipated (and 
perhaps better than I could have done) results of which as 
yet I had but a glimpse, &€., &e. 
