ADVERTISEMENT TO THE SECOND EDITION. 11 
splendid works, wherein new species are described and figured, and of which the 
authors have striven to detect their mutual relations, and to consider them in every 
point of view.* 
I have endeavoured to avail myself of these discoveries, as far as my plan permitted, 
by first studying the innumerable specimens received at the Cabinet du Roi, and com- 
paring them with those which served as the basis of my first edition, in order 
thence to deduce new approximations or subdivisions ; and then, by searching in all 
I the books I could procure for the genera or sub -genera established by naturalists, 
and the descriptions of species by which they have supported these numerous com- 
binations. 
The determination of synonymes has become much easier now than at the period 
of my first edition. Both French and foreign naturalists appear to have recognized 
the necessity of establishing divisions in the vast genera in which such incongruous 
species were formerly heaped together ; their groups are now precise and well-defined ; 
their descriptions sufficiently detailed ; their figures scrupulously exact to the most 
minute characters, and often of the greatest beauty as works of art. Scarcely any 
difficulty remains, therefore, in identifying their species, and nothing hinders 
' them from coming to an understanding with respect to the nomenclature. This, 
ji unfortunately, has been the most neglected ; the names of the same genera, and the 
' same species, are multiplied as often as they are mentioned ; and should this discord 
: continue, the same chaos will be produced that previously existed, though arising 
from another cause. 
I I have used every effort to compare and approximate these redundancies, and, forget- 
, ting even my own trifling interest as an author, have often indicated names which 
I seemed to have been imagined only to escape the avowal of having borrowed my divisions, 
j But thoroughly to execute this undertaking, — this pinax or rectified epitome of the 
■ animal kingdom, which becomes every day more necessary, — to discuss the proofs and fix 
the definitive nomenclature which should be adopted, by basing it on sufficient figures 
and descriptions, requires more space than I could dispose of, and a time imperatively 
j claimed by other works. In the History of Fishes, which I have commenced pub- 
lishing, with the assistance of M. Valenciennes, I purpose to give an idea of what 
' appears to me might be effected in all parts of the science. Here, I only profess to 
offer an abridged summary — a simple sketch ; — well satisfied if I succeed in rendering 
this accurate in all its details. 
Various essays of a similar kind have been published on some of the classes, 
and I have carefully studied them with a view to perfect my own. The Mammalogie 
of M. Desmarest, that of M. Lesson, the Treatise on the Teeth of Quadrupeds, by 
j M. Frederic Cuvier, the English translation of my first edition, by Mr. Griffith, 
enriched by numerous additions, particularly by Hamilton Smith ; the new edition 
I of the Manuel d' OrnitJiologie of M. Temminck, the Ornithological Fragments of 
I M. Wagler, the History of Reptiles of the late Merrem, and the Dissertation on the 
same subject by M. Fitsinger, have principally been useful to me for the vertebrated 
animals. The Histone des Animaux sans Vertebres of M. de Lamarck, the Malacologie 
of M. de Blainville, have also been of great service to me for the moUusks. To 
* See my discourse before the Institute on the Progres de Vhistoire naturelle depuis la paix maritime, published at the dose of the first 
volume of my Eloges. 
