CHAPTER IX. 
THE ORDER OF SUCCESSION OF THE REGIONS.—COSMOPOLITAN 
GROUPS OF ANIMALS.—TABLES OF DISTRIBUTION. 
HAVING discussed, in our First Part, such general and preliminary 
matters as are necessary to a proper comprehension of our 
subject ; and having made ourselves acquainted, in our Second 
Part, with the most important results of Paleontology, we now 
come to our more immediate subject, which we propose to treat 
first under its geographical aspect. Taking each of our six 
regions in succession, we shall point out in some detail the chief 
zoological features they present, as influenced by climate, vege- 
tation, and other physical features. We shall then treat each 
of the sub-regions by itself, as well as such of the islands or 
other sub-divisions as present features of special interest ; en- 
deavouring to ascertain their true relations to each other, and the 
more important changes of physical geography that seem neces- 
sary to account for their present zoological condition. 
Order of Succession of the Regions— We may here explain 
the reason for taking the several regions in a different succession 
from that in which they appear in the tabular or diagrammatic 
headings to each family, in the Fourth, and concluding part of 
this work. It will have been seen, by our examination of extinct 
animals (and it will be made still clearer during our study of 
the several regions) that all the chief types of animal life appear 
to have originated in the great north temperate or northern 
continents; while the southern continents—now represented by 
