to the operation of disease. The dark-skinned Hyperboreans are
found in the Frigid Zone ; regions most congenial to their nature, and
from which they cannot be enticed by more temperate climes. The
Mongols of Asia, and the aborigines of America, with their peculiar
types, are spread over almost all degrees of latitude.
I So is it with the whole range of Mammifers, as well as birds, and
other genera. The lightest and the darkest colors — the most gorgeous
and most sombre plumage, are everywhere found beside each
other ; though brilliant feathers and colors are commoner in the
tropics, where men are generally more or less dark.
Every spot on the earth’s surface, from pole to pole — the mountains
and valleys, the dry land and the water — has its organized
beings, which find around a given centre all the conditions necessary
for their preservation. These living beings are as innumerable as
the conditions of the places they inhabit; and their ÿfferent stations
are as varied as their instincts and habits. To consider these stations
under the simple point of view of the distribution of heat on their
surface, is absolutely to see hut one of,the'many secondary natural
causes that influence organized beings.
Amidst the infinitude of beings spread over the globe, the Class of
Mammifers stands first in organization, and at its head Zoologists
have placed the Bimanes (Mankind).. It is the least numerous, and
its généra and species are almost entirely known.
This class is composed of about 200 genera, which may he divided
into two parts. 1st. Those whose habitations are limited to a single
Zone. 2d. Those, on the contrary, which are scattered through all
the Zones. There would at first seem to he a striking contrast
between these two divisions ; on the one side, complete immobility,
and on the other, great mobility ; hut this irregularity is only apparent,
for when we examine attentively the différent genera, we find them
governed by the same laws. Those of the first division, whose habitat
is limited, are in general confined to a few species ; while those of
the second, on the contrary, contain many species, hut which are
themselves confined to certain localities, in the same manner as the
fewer genera of the first division. Thus we find the same law
governing species in both instances. "We will cite a single example
out of. many. The White Bear is confined to the Polar regions,
while other ursine species inhabit the temperate climates of the
mountain chains of Europe and America; and finally, the Malay
Bear, and the Bear of Borneo, are restricted to torrid climates.
We may then consider the different species of Mammifers as ranged
under an identical law of geographical distribution, and that each
species on the globe has its limited space, beyond which it does not
extend ; and that every country on the globe, whatever may he its
temperature, its analogies, or differences of climate, possesses ite
own Mammifers, different from those of -ether countries, belonging
to its region alone. There are apparent exceptions to this law, hut
they are all susceptible of explanation.15
A few species are really common to the two continents, hut only in
the1 Arctic region. America and Asia are there united by icy plains,
which may he easily traversed by certain animals ; and, while the
White Bear, the Wolf, the Red Fox, the Glutton, are common to
both, the continents and "climates may there he really considered as
one. We shall show, as we proceed, that with a few exceptions in the
Arctic region, the Faunae and Florae of the two continents are entirely
distinct, and that even the Temperate Zones of ISTorth and South
America do not present the same types, although they are separated
by mere table-lands, presenting none of the extremes of climate
encountered in the Tropic of Africa.
But this' immobility, imposed by nature on its creatures, is illustrated
in a still more striking manner if we turn to those Mammifers that
inhabit the ocean, where there are no appreciable, impediments, none
of those infinitely varied conditions which are seen upon land, even
in the same parallels of latitude. The temperature of the ocean
varies all but insensibly with degrees of latitude; and among the
immense crowd of animals that inhabit it, we find numerous families
of Mammifers. Although endowed with great powers of locomotion,
and notwithstanding the trifling obstacles opposed to them, they are,
like animals of the land, limited to certain localities. The genera
Qalocephalus, Stemmatopes and Morse, are peculiar to the FTorthern
Seas. In the Southern, on the contrary, we find the- genera Otarie,
Stenorynchus, Platyrynchus, &c. Other species inhabit only hot or
temperate regions.
The various species of Whales and Dolphins, despite their prodigious
powers of locomotion, are confined each to regions originally
assigned them ; and, while there is so little difference of temperature
in the ocean, that a human being might, in the mild season, swim
with delight from the Horth Temperate Zone to Cape Horn, along
eithei’ coast of America, there is no degree of latitude in which we
do not discover species peculiar to itself.
After a resumé of these and many kindred facts, M. Jacquinot
uses this emphatic language :
“ To recapitulate, it seems to us, after all we have said, that we may draw the following
conclusions, viz., that all Mammifers on the globe have a habitation, limited and circumscribed,
which they never overleap ; their assemblage contributes to give to each country its
particular stamp of creation. What a contrast between the Mammifers of the Old and
New World, and the creations, so special and so singular, of New Holland and Madagascar ! *
9