geographical surface, climate, and other conditions, for their existence.
And it is everywhere found that, however isolated a particular spot may
be with regard to these conditions,—as a mountain top in a torrid
country, the marsh round a salt spring far inland, or an island placed
far apart in the ocean,—appropriate plants have there taken up their
abode. But the torrid zone divides the two temperate regions from each
other by the space of more than forty-six degrees, and the torrid and
temperate zones together form a much broader line of division between the
two arctic regions. The Atlantic and Pacific Oceans, and the Persian
Gulf, also divide the various portions of continent in the torrid and
temperate zones from each other. Australia is also divided by a broad
sea from the continent of Asia. Thus there are various portions of the
earth separated from each other in such a way as to preclude anything
like a general communication of the seeds of their respective plants
towards each other. Hence arises an interesting question—Are the plants
of the various isolated regions which enjoy a parity of climate and other
conditions, identical or the reverse? The answer is—that in such regions
the vegetation bears a general resemblance, but the _species_ are nearly
all different, and there is even, in a considerable measure, a diversity
of families.
The general facts have been thus stated: in the arctic and antarctic
regions, and in those parts of lower latitudes, which, from their
elevation, possess the same cold climate, there is always a similar or
analogous vegetation, but few species are common to the various
situations. In like manner, the intertropical vegetation of Asia,
Africa, and America, are specifically different, though generally
similar. The southern region of America is equally diverse from that of
Africa, a country similar in clime, but separated by a vast extent of
ocean. The vegetation of Australia, another region similarly placed in
respect of clime, is even more peculiar. These facts are the more
remarkable when we discover that, in most instances, the plants of one
region have thriven when transplanted to another of parallel clime. This
would shew that parity of conditions does not lead to a parity of
productions so exact as to include identity of species, or even genera.
Besides the various isolated regions here enumerated, there are some
others indicated by naturalists as exhibiting a vegetation equally
peculiar. Some of these are isolated by mountains, or the interposition
of sandy wastes. For example, the temperate region of the elder
continent is divided about the centre of Asia, and the east of that line
is different from the west. So also is the same region divided in North
America by the Rocky Mountains. Abyssinia and Nubia constitute another
distinct botanical region. De Candolle enumerates in all twenty
well-marked portions of the earth’s surface which are peculiar with
respect to vegetation; a number which would be greatly increased if
remote islands and isolated mountain ranges were to be included.
When we come to the zoology, we find precisely similar results, excepting
that man (with, perhaps, some of the less conspicuous forms of being) is
universal, and that several tribes, as the bear and dog, appear to have
passed by the land connexion from the arctic regions of the eastern to
those of the western hemisphere. “With these exceptions,” says Dr.
Prichard, “and without any others, as far as zoological researches have
yet gone, it may be asserted that no individual species are common to
distant regions. In parallel climates, analogous species replace each
other; sometimes, but not frequently, the same genus is found in two
separate continents; but the species which are natives of one region are
not identical with corresponding races indigenous in the opposite
hemisphere.
“A similar result arises when we compare the three great intertropical
regions, as well as the extreme spaces of the three great continents,
which advance into the temperate climates of the southern hemisphere.
“Thus, the tribes of simiæ, (monkeys,) of the dog and cat kinds, of
pachyderms, including elephants, tapirs, rhinoceroses, hogs, of bats, of
saurian and ophidian reptiles, as well of birds and other terrene
animals, are all different in the three great continents. In the lower
departments of the mammiferous family, we find that the bruta, or
edendata, (sloths, armadillos, &c.,) of Africa, are differently organized
from those of America, and these again from the tribes found in the
Malayan archipelago and Terra Australis.” {255}
It does not appear that the diversity between the similar regions of
Africa, Asia, and America, is occasioned in all instances by any
disqualification of these countries to support precisely the same genera
or species. The ox, horse, goat, &c., of the elder continent have
thriven and extended themselves in the new, and many of the indigenous
tribes of America would no doubt flourish in corresponding climates in
Europe, Asia, and Africa. It has, however, been remarked by naturalists
unacquainted with the Macleay system, that the larger and more powerful
animals of their respective orders belong to the elder continent, and
that thus the animals of America, unlike the features of inanimate
nature, appear to be upon a small scale. The swiftest and most agile
animals, and a large proportion of those most useful to man, are also
natives of the elder continent. On the other hand, the bulk of the
edentata, a group remarkable for defects and meanness of organization,
are American. The zoology of America may be said, upon the whole, to
recede from that of Asia, “and perhaps in a greater degree,” adds Dr.
Prichard, “from that of Africa.” A much greater recession is, however,
observed in both the botany and zoology of Australia.
There “we do not find, in the great masses of vegetation, either the
majesty of the virgin forests of America, or the variety and elegance of
those of Asia, or the delicacy and freshness of the woods of our
temperate countries of Europe. The vegetation is generally gloomy and
sad; it has the aspect of our evergreens or heaths; the plants are for
the most part woody; the leaves of nearly all the plants are linear,
lanceolated, small, coriaceous, and spinescent. The grasses, which
elsewhere are generally soft and flexible, participate in the stiffness
of the other vegetables. The greater part of the plants of New Holland
belong to new genera; and those included in the genera already known are
of new species. The natural families which prevail are those of the
heaths, the proteæ, compositæ, leguminosæ, and myrthoideæ; the larger
trees all belong to the last family.” {257}
The prevalent animals of Australia are not less peculiar. It is well
known that none above the marsupialia, or pouched animals, are native to
it. The most conspicuous are these marsupials, which exist in great
varieties here, though unknown in the elder continent, and only found in
a few mean forms in America. Next to them are the monotremata, which are
entirely peculiar to this portion of the earth. Now these are animals at
the bottom of the mammiferous class, adjoining to that of birds, of whose
character and organization the monotremata largely partake, the
ornithorynchus presenting the bill and feet of a duck, producing its
young in eggs, and having, like birds, a clavicle between the two
shoulders. The birds of Australia vary in structure and plumage, but all
have some singularity about them—the swan, for instance, is black. The
country abounds in reptiles, and the prevalent fishes are of the early
kinds, having a cartilaginous structure.
Altogether, the plants and animals of this minor continent convey the
impression of an early system of things, such as might be displayed in
other parts of the earth about the time of the oolite. In connexion with
this circumstance, it is a fact of some importance, that the geognostic
character of Australia, its vast arid plains, its little diversified
surface and consequent paucity of streams, and the very slight
development of volcanic rock on its surface, seem to indicate a system of
physical conditions, such as we may suppose to have existed elsewhere in
the oolitic era: perhaps we see the chalk formation preparing there in
the vast coral beds frontiering the coast. Australia thus appears as a
portion of the earth which has, from some unknown causes, been belated in
its physical and organic development. And certainly the greater part of
its surface is not fitted to be an advantageous place of residence for
beings above the marsupialia, and judging from analogy, it may yet be
subjected to a series of changes in the highest degree inconvenient to
any human beings who may have settled upon it.
The general conclusions regarding the geography of organic nature, may be
thus stated. (1.) There are numerous distinct foci of organic production
throughout the earth. (2.) These have everywhere advanced in accordance
with the local conditions of climate &c., as far as at least the class
and order are concerned, a diversity taking place in the lower
gradations. No physical or geographical reason appearing for this
diversity, we are led to infer that, (3,) it is the result of minute and
inappreciable causes giving the law of organic development a particular
direction in the lower subdivisions of the two kingdoms. (4.)
Development has not gone on to equal results in the various continents,
being most advanced in the eastern continent, next in the western, and
least in Australia, this inequality being perhaps the result of the
comparative antiquity of the various regions, geologically and
geographically.
It must at the same time be admitted that the line of organic development
has nowhere required for its advance the whole of the families
comprehended in the two kingdoms, seeing that some of these are confined
to one continent, and some to another, without a conceivable possibility
of one having been connected with the other in the way of ancestry. The
two great families of quadrumana, cebidæ and simiadæ, are a noted
instance, the one being exclusively American, while the other belongs
entirely to the old world. There are many other cases in which the full
circular group can only be completed by taking subdivisions from various
continents. This would seem to imply that, while the entire system is so
remarkable for its unity, it has nevertheless been produced in lines
geographically detached, these lines perhaps consisting of particular
typical groups placed in an independent succession, or of two or more of
these groups. And for this idea there is, even in the present imperfect
state of our knowledge of animated nature, some countenance in
ascertained facts, the birds of Australia, for example, being chiefly of
the suctorial type, while it may be presumed that the observation as to
the predominance of the useful animals in the Old World, is not much
different from saying that the rasorial type is there peculiarly
abundant. It does not appear that the idea of independent lines,
consisting of particular types, or sets of types, is necessarily
inconsistent with the general hypothesis, as nothing yet ascertained of
the Macleay system forbids their having an independent set of affinities.
On this subject, however, there is as yet much obscurity, and it must be
left to future inquirers to clear it up.
We must now call to mind that the geographical distribution of plants and
animals was very different in the geological ages from what it is now.
Down to a time not long antecedent to man, the same vegetation overspread
every clime, and a similar uniformity marked the zoology. This is
conceived by M. Brogniart, with great plausibility, to have been the
result of a uniformity of climate, produced by the as yet unexhausted
effect of the internal heat of the earth upon its surface; whereas
climate has since depended chiefly on external sources of heat, as
modified by the various meteorological influences. However the early
uniform climate was produced, certain it is that, from about the close of
the geological epoch, plants and animals have been dispersed over the
globe with a regard to their particular characters, and specimens of both
are found so isolated in particular situations, as utterly to exclude the
idea that they came thither from any common centre. It may be
asked,—Considering that, in the geological epoch, species are not limited
to particular regions, and that since the close of that epoch, they are
very peculiarly limited, are we to presume the present organisms of the
world to have been created _ab initio_ after that time? To this it may
be answered,—Not necessarily, as it so happens that animals begin to be
much varied, or to appear in a considerable variety of species, towards
the close of the geological history. It may have been that the
multitudes of locally peculiar species only came into being after the
uniform climate had passed away. It may have only been when a varied
climate arose, that the originally few species branched off into the
present extensive variety.
A question of a very interesting kind will now probably arise in the
reader’s mind—_What place or status is assigned to man in the new natural
system_. Before going into this inquiry, it is necessary to advert to
several particulars of the natural system not yet noticed.
It is necessary, in particular, to ascertain the grades which exist in
the classification of animals. In the line of the aves, Mr. Swainson
finds these to be nine, the species pica, for example, being thus
indicated:—
Kingdom Animalia.
Sub-kingdom Vertebrata.
Class Aves.
Order Incessores.
Tribe Conirostres.
Family Corvidæ.
Sub-family Corvinæ.
Genus Corvus.
Sub-genus, or species Pica.
This brings us down to species, the subdivision where intermarriage or
breeding is usually considered as natural to animals, and where a
resemblance of offspring to parents is generally persevered in. The dog,
for instance, is a species, because all dogs can breed together, and the
progeny partakes of the appearances of the parents. The human race is
held as a species, primarily for the same reasons. Species, however, is
liable to another subdivision, which naturalists call variety; and
variety appears to be subject to exactly the same system of
_representation_ which have been traced in species and higher
denominations. In canis, for instance, the bull-dog and mastiff
represent the ferocious sub-typical group; the waterdog is natatorial; we
see the speed and length of muzzle of the suctorial group in the
greyhound; and the bushy tail and gentle and serviceable character of the
rasorial in the shepherd’s dog and spaniel. Even the striped and spotted
skin of the tiger and panther is reproduced in the more ferocious kind of
dogs—an indication of a fundamental connexion between physical and mental
qualities which we have also seen in the zebra, and which is likewise
displayed in the predominance of a yellow colour in the vultures and owls
in common with the lion and his congeners.
It is by no means clearly made out that this system of nine gradations
over and above that of variety applies in all departments of nature. On
the contrary, even Mr. Swainson gives series in which several of them are
omitted. It may be that, in some departments of nature, variation from
the class or order has gone down into fewer shades than in others; or it
may be, that many of the variations have not survived till our era, or
have not been as yet detected by naturalists; in either of which cases
there may be a necessity for shortening the series by the omission of one
or two grades, as for instance _tribe_ or _sub-family_. This, however,
is much to be regretted, as it introduces an irregularity into the
natural system, and consequently throws a difficulty and doubt in the way
of our investigating it. With these preliminary remarks, I shall proceed
to inquire what is the natural status of man.
That man’s place is to be looked for in the class mammalia and
sub-kingdom vertebrata admits of no doubt, from his possessing both the
characters on which these divisions are founded. When we descend,
however, below the _class_, we find no settled views on the subject
amongst naturalists. Mr. Swainson, who alone has given a review of the
animal kingdom on the Macleay system, unfortunately writes on this
subject in a manner which excites a suspicion as to his judgment. His
arrangement of the first or typical order of the mammalia is therefore to
be received with great hesitation. It is as follows:—
Typical Quadrumana Pre-eminently organized for
grasping.
Sub-typical Feræ Claws retractile; carnivorous.
Natatorial Cetacea Pre-eminently aquatic; feet very
short.
Suctorial Glires Muzzle lengthened and pointed.
Rasorial Ungulata Crests and other processes on the
head.
He then takes the quadrumana, and places it in the following
arrangement:—
Typical Simiadæ (Monkeys of Old World.)
Sub-typical Cebidæ (Monkeys of New World.)
Natatorial Unknown
Suctorial Vespertilionidæ (Bats.)
Rasorial Lemuridæ (Lemurs.)
He considers the simiadæ as a complete circle, and argues thence that
there is no room in the range of the animal kingdom for man. Man, he
says, is not a constituent part of any circle, for, if he were, there
ought to be other animals on each hand having affinity to him, whereas
there are none, the resemblance of the orangs being one of mere analogy.
Mr. Swainson therefore considers our race as standing apart, and forming
a link between the unintelligent order of beings and the angels! And
this in spite of the glaring fact that, in our teeth, hands, and other
features grounded on by naturalists as characteristic, we do not differ
more from the simiadæ than the bats do from the lemurs—in spite also of
that resemblance of analogy to the orangs which he himself admits, and
which, at the least, must be held to imply a certain relation. He also
overlooks that, though there may be no room for man in the circle of the
simiadæ, (this, indeed, is quite true,) there may be in the order, where
he actually leaves a place entirely blank, or only to be filled up, as he
suggests, by mermen! {266} Another argument in his arrangement is, that
it leaves the grades of classification very much abridged, there being at
the most seven instead of nine. But serious argument on a theory so
preposterous may be considered as nearly thrown away. I shall therefore
at once proceed to suggest a new arrangement of this portion of the
animal kingdom, in which man is allowed the place to which he is
zoologically entitled.
I propose that the typical order of the mammalia should be designated
cheirotheria, from the sole character which is universal amongst them,
their possessing hands, and with a regard to that pre-eminent
qualification for grasping which has been ascribed to them—an analogy to
the perching habit of the typical order of birds, which is worthy of
particular notice. The tribes of the cheirotheria I arrange as follows:—
Typical Bimana.
Sub-typical Simiadæ.
Natatorial Vespertilionidæ.
Suctorial Lemuridæ.
Rasorial Cebidæ.
Here man is put into the typical place, as the genuine head, not only of
this order, but of the whole animal world. The double affinity which is
requisite is obtained, for here he has the simiadæ on one hand, and the
cebidæ on the other. The five tribes of the order are completed, the
vespertilionidæ being shifted (provisionally) into the natatorial place,
for which their appropriateness is so far evidenced by the aquatic habits
of several of the tribe, and the lemuridæ into the suctorial, to which
their length of muzzle and remarkable saltatory power are highly
suitable. At the same time, the simiadæ are degraded from the typical
place, to which they have no sort of pretension, and placed where their
mean and mischievous character seem to require; the cebidæ again being
assigned that situation which their comparatively inoffensive
dispositions, their arboreal habits, and their extraordinary development
of the tail, (which with them is like a fifth hand,) render so proper.
The zoological status thus assigned to the human race is precisely what
might be expected. In order to understand its full value, it is
necessary to observe how the various type peculiarities operate in fixing
the character of the animals ranked in them. It is easy to conceive that
they must be, in some instances, much mixed up with each other, and
consequently obscured. If an animal, for example, is the suctorial
member of a circle of species, forming the natatorial type of genera,
forming a family or sub-family which in its turn is rasorial, its
qualities must evidently be greatly mingled and ill to define. But, on
the other hand, if we take the rapacious or sub-typical group of birds,
and look in it for the tribe which is again the rapacious or sub-typical
group of its order, we may expect to find the qualities of that group
exalted or intensified, and accordingly made the more conspicuous. Such
is really the case with the vultures, in the rapacious birds, a family
remarkable above all of their order for their carnivorous and foul
habits. So, also, if we take the typical group of the birds, the
incessores or perchers, and look in it for its typical group, the
conirostres, and seek there again for the typical family of that group,
the corvidæ, we may expect to find a very marked superiority in
organization and character. Such is really the case. “The crow,” says
Mr. Swainson, “unites in itself a greater number of properties than are
to be found individually in any other genus of birds; as if in fact it
had taken from all the other orders a portion of their peculiar
qualities, for the purpose of exhibiting in what manner they could be
combined. From the rapacious birds this “type of types,” as the crow has
been justly called, takes the power of soaring in the air, and of seizing
upon living birds, like the hawks, while its habit of devouring putrid
substances, and picking out the eyes of young animals, is borrowed from
the vultures. From the scansorial or climbing order it takes the faculty
of picking the ground, and discovering its food when hidden from the eye,
while the parrot family gives it the taste for vegetable food, and
furnishes it with great cunning, sagacity, and powers of imitation, even
to counterfeiting the human voice. Next come the order of waders, who
impart their quota to the perfection of the crow by giving it great
powers of flight, and perfect facility in walking, such being among the
chief attributes of the suctorial order. Lastly, the aquatic birds
contribute their portion, by giving this terrestrial bird the power of
feeding not only on fish, which are their peculiar food, but actually of
occasionally catching it. {270} In this wonderful manner do we find the
crow partially invested with the united properties of all other birds,
while in its own order, that of the incessores or perchers, it stands the
pre-eminent type. We cannot also fail to regard it as a remarkable proof
of the superior organization and character of the corvidæ, that they are
adapted for all climates, and accordingly found all over the world.