MAMMALIA OF EOCENE PERIOD. 87 
It appears that the animal kingdom was thus 
early established, on the same general prin- 
ciples that now prevail ; not only did the four 
present Classes of Vertebrata exist ; and among 
Mammalia, the Orders Pachydermata, Carni- 
vora, Rodentia, and Marsupialia ; but many of 
the genera also, into which living families are 
distributed, were associated together in the same 
system of adaptations and relations, which they 
hold to each other in the actual creation. The 
Pachydermata and Rodentia were kept in check 
by the Carnivora — the Gallinaceous birds were 
controlled by the Accipitres. 
'* Le R^gne Animal, k ces ^poques reculees, 
etait compose d'apres les memes lois ; il com- 
prenoit les memes classes, les memes families 
que de nos jours ; et en effet, parmi les divers 
syst^mes sur I'origine des etres organises, il n'en 
est pas de moins vraisemblable que celui qui en 
fait naitre successivement les differens genres 
par des developpemens ou des metamorphoses 
graduelles." (Cuvier, Oss. Foss. t. 3, p. 297.) 
This numerical preponderance of Pachyder- 
mata, among the earliest fossil Mammalia, be- 
yond the proportion they bear among existing 
quadrupeds, is a remarkable fact, much insisted 
on by Cuvier ; because it supplies, from the 
relics of a former world, many intermediate 
forms which do not occur in the present distri- 
bution of that important Order. As the living 
genera of Pachydermata are more widely sepa- 
