Kitabı oku: «Mythical Monsters», sayfa 2

The vast treasures of ancient knowledge tombed in the ruins of Babylon and Assyria, of which the recovery and deciphering is as yet only initiated, may, to our surprise, reveal that certain secrets of philosophy were known to the ancients equally with ourselves, but lost through intervening ages by the destruction of the empire, and the fact of their conservancy having been entrusted to a privileged and limited order, with which it perished.³³

We hail as a new discovery the knowledge of the existence of the so-called spots upon the surface of the sun, and scientists, from long-continued observations, profess to distinguish a connection between the character of these and atmospheric phenomena; they even venture to predict floods and droughts, and that for some years in anticipation; while pestilences or some great disturbance are supposed to be likely to follow the period when three or four planets attain their apogee within one year, a supposition based on the observations extended over numerous years, that similar events had accompanied the occurrence of even one only of those positions at previous periods.

May we not speculate on the possibility of similar or parallel knowledge having been possessed by the old Chaldæan and Egyptian priesthood; and may not Joseph have been able, by superior ability in its exercise, to have anticipated the seven years’ drought, or Noah, from an acquaintance with meteorological science, to have made an accurate forecast of the great disturbances which resulted in the Deluge and the destruction of a large portion of mankind?³⁴

Without further digression in a path which opens the most pleasing speculations, and could be pursued into endless ramifications, I will merely, in conclusion, suggest that the same influences which, as I have shown above, affect so largely the very nature of a people, must similarly affect its traditions and myths, and that due consideration will have to be given to such influences, in the case of some at least of the remarkable animals which I propose to discuss in this and future volumes.

Chronological List of some Authors writing on, and Works relating to Natural History, to which References are made in the present Volume; extracted to a great extent, as to the Western Authors, from Knight’s “Cyclopædia of Biography.”

The Shan Hai King– According to the commentator Kwoh P’oh (A.D. 276-324), this work was compiled three thousand years before this time, or at seven dynasties’ distance. Yang Sun of the Ming dynasty (commencing A.D. 1368), states that it was compiled by Kung Chia (and Chung Ku?) from engravings on nine urns made by the Emperor Yü, B.C. 2255. Chung Ku was an historiographer, and at the time of the last Emperor of the Hia dynasty (B.C. 1818), fearing that the Emperor might destroy the books treating of the ancient and present time, carried them in flight to Yin.

The ’Rh Ya– Initiated according to tradition, by Chow Kung; uncle of Wu Wang, the first Emperor of the Chow dynasty, B.C. 1122. Ascribed also to Tsze Hea, the disciple of Confucius.

The Bamboo Books– Containing the Ancient Annals of China, said to have been found A.D. 279, on opening the grave of King Seang of Wei [died B.C. 295]. Age prior to last date, undetermined. Authenticity disputed, favoured by Legge.

Confucius– Author of Spring and Autumn Classics, &c., B.C. (551-479).

Ctesias– Historian, physician to Artaxerxes, B.C. 401.

Herodotus– B.C. 484.

Aristotle– B.C. 384.

Megasthenes– About B.C. 300. In time of Seleucus Nicator. His work entitled Indica is only known by extracts in those of Strabo, Arrian, and Ælian.

Eratosthenes– Born B.C. 276. Mathematician, Astronomer, and Geographer.

Posidonius– Born about B.C. 140. Besides philosophical treatises, wrote works on geography, history, and astronomy, fragments of which are preserved in the works of Cicero, Strabo, and others.

Nicander– About B.C. 135. Wrote the Theriaca, a poem of 1,000 lines, in hexameter, on the wounds caused by venomous animals, and the treatment. Is followed in many of his errors by Pliny. Plutarch says the Theriaca cannot be called a poem, because there is in it nothing of fable or falsehood.

Strabo– Just before the Christian era. Geographer.

Cicero– Born B.C. 106.

Propertius (Sextus Aurelius) – Born probably about B.C. 56.

Diodorus Siculus– Wrote the Bibliotheca Historica (in Greek), after the death of Julius Cæsar (B.C. 44). Of the 40 books composing it only 15 remain, viz. Books 1 to 5 and 11 to 20.

Juba– Died A.D. 17. Son of Juba I., King of Numidia. Wrote on Natural History.

Pliny– Born A.D. 23.

Lucan– A.D. 38. The only work of his extant is the Pharsalia, a poem on the civil war between Cæsar and Pompey.

Ignatius– Either an early Patriarch, A.D. 50, or Patriarch of Constantinople, 799.

Isidorus– Isidorus of Charaux lived probably in the first century of our era. He wrote an account of the Parthian empire.

Arrian– Born about A.D. 100. His work on the Natural History, &c. of India is founded on the authority of Eratosthenes and Megasthenes.

Pausanias– Author of the Description or Itinerary of Greece. In the 2nd century.

Philostratus– Born about A.D. 182.

Solinus, Caius Julius– Did not write in the Augustan age, for his work entitled Polyhistor is merely a compilation from Pliny’s Natural History. According to Salmasius, he lived about two hundred years after Pliny.

Ælian– Probably middle of the 3rd century A.D. De Naturâ Animalium. In Greek.

Ammianus Marcellinus– Lived in 4th century.

Cardan, Jerome A.– About the end of 4th century A.D.

Printing invented in China, according to Du Halde, A.D. 924. Block-printing used in A.D. 593.

Marco Polo– Reached the Court of Kublai Khan in A.D. 1275.

Mandeville, Sir John de– Travelled for thirty-three years in Asia dating from A.D. 1327. As he resided for three years in Peking, it is probable that many of his fables are derived from Chinese sources.

Printing invented in Europe by John Koster of Haarlem, A.D. 1438.

Scaliger, Julius Cæsar– Born April 23rd, 1484. Wrote Aristotelis Hist. Anim. liber decimus cum vers. et comment. 8vo. Lyon, 1584, &c.

Gesner– Born 1516. Historiæ Animalium, &c.

Ambrose Paré– Born 1517. Surgeon.

Belon, Pierre– Born 1518. Zoologist, Geographer, &c.

Aldrovandus– Born 1552. Naturalist.

Tavernier, J. B.– Born 1605.

Păn Ts’ao Kang Muh– By Li Shê-chin of the Ming dynasty (A.D. 1368-1628).

Yuen Kien Léi Han– A.D. 1718.

CHAPTER I.
ON SOME REMARKABLE ANIMAL FORMS

The reasoning upon the question whether dragons, winged snakes, sea-serpents, unicorns, and other so-called fabulous monsters have in reality existed, and at dates coeval with man, diverges in several independent directions.

We have to consider: —

1. – Whether the characters attributed to these creatures are or are not so abnormal in comparison with those of known types, as to render a belief in their existence impossible or the reverse.

2. – Whether it is rational to suppose that creatures so formidable, and apparently so capable of self-protection, should disappear entirely, while much more defenceless species continue to survive them.

3. – The myths, traditions, and historical allusions from which their reality may be inferred require to be classified and annotated, and full weight given to the evidence which has accumulated of the presence of man upon the earth during ages long prior to the historic period, and which may have been ages of slowly progressive civilization, or perhaps cycles of alternate light and darkness, of knowledge and barbarism.

4. – Lastly, some inquiry may be made into the geographical conditions obtaining at the time of their possible existence.

It is immaterial which of these investigations is first entered upon, and it will, in fact, be more convenient to defer a portion of them until we arrive at the sections of this volume treating specifically of the different objects to which it is devoted, and to confine our attention for the present to those subjects which, from their nature, are common and in a sense prefatory to the whole subject.

I shall therefore commence with a short examination of some of the most remarkable reptilian forms which are known to have existed, and for that purpose, and to show their general relations, annex the accompanying tables, compiled from the anatomy of vertebrated animals by Professor Huxley: —

REPTILES CLASSIFIED BY HUXLEY.

The most bird-like of reptiles, the Pterosauria, appear to have possessed true powers of flight; they were provided with wings formed by an expansion of the integument, and supported by an enormous elongation of the ulnar finger of the anterior limb. The generic differences are based upon the comparative lengths of the tail, and upon the dentition. In Pterodactylus (see Fig. 2, p. 18), the tail is very short, and the jaws strong, pointed, and toothed to their anterior extremities. In Rhamphorynchus (see Fig. 8, p. 18), the tail is very long and the teeth are not continuous to the extremities of the jaws, which are produced into toothless beaks. The majority of the species are small, and they are generally considered to have been inoffensive creatures, having much the habits and insectivorous mode of living of bats. One British species, however, from the white chalk of Maidstone, measures more than sixteen feet across the outstretched wings; and other forms recently discovered by Professor Marsh in the Upper Cretaceous deposits of Kansas, attain the gigantic proportions of nearly twenty-five feet for the same measurements; and although these were devoid of teeth (thus approaching the class Aves still more closely), they could hardly fail, from their magnitude and powers of flight, to have been formidable, and must, with their weird aspects, and long outstretched necks and pointed heads, have been at least sufficiently alarming.

We need go no farther than these in search of creatures which would realise the popular notion of the winged dragon.

The harmless little flying lizards, belonging to the genus Draco, abounding in the East Indian archipelago, which have many of their posterior ribs prolonged into an expansion of the integument, unconnected with the limbs, and have a limited and parachute-like flight, need only the element of size, to render them also sufficiently to be dreaded, and capable of rivalling the Pterodactyls in suggesting the general idea of the same monster.

It is, however, when we pass to some of the other groups, that we find ourselves in the presence of forms so vast and terrible, as to more than realise the most exaggerated impression of reptilian power and ferocity which the florid imagination of man can conceive.

We have long been acquainted with numerous gigantic terrestrial Saurians, ranging throughout the whole of the Mesozoic formations, such as Iguanodon (characteristic of the Wealden), Megalosaurus (Great Saurian), and Hylæosaurus (Forest Saurian), huge bulky creatures, the last of which, at least, was protected by dermal armour partially produced into prodigious spines; as well as with remarkable forms essentially marine, such as Icthyosaurus (Fish-like Saurian), Plesiosaurus, &c., adapted to an oceanic existence and propelling themselves by means of paddles. The latter, it may be remarked, was furnished with a long slender swan-like neck, which, carried above the surface of the water, would present the appearance of the anterior portion of a serpent.

To the related land forms the collective term Dinosauria (from δεινός “terrible”) has been applied, in signification of the power which their structure and magnitude imply that they possessed; and to the others that of Enaliosauria, as expressive of their adaptation to a maritime existence. Yet, wonderful to relate, those creatures which have for so many years commanded our admiration fade into insignificance in comparison with others which are proved, by the discoveries of the last few years, to have existed abundantly upon, or near to, the American continent during the Cretaceous and Jurassic periods, by which they are surpassed, in point of magnitude, as much as they themselves exceed the mass of the larger Vertebrata.

Take, for example, those referred to by Professor Marsh in the course of an address to the American Association for the Advancement of Science, in 1877, in the following terms: – “The reptiles most characteristic of our American cretaceous strata are the Mososauria, a group with very few representatives in other parts of the world. In our cretaceous seas they rule supreme, as their numbers, size, and carnivorous habits enabled them to easily vanquish all rivals. Some were at least sixty feet in length, and the smallest ten or twelve. In the inland cretaceous sea from which the Rocky Mountains were beginning to emerge, these ancient ‘sea-serpents’ abounded, and many were entombed in its muddy bottom; on one occasion, as I rode through a valley washed out of this old ocean-bed, I saw no less than seven different skeletons of these monsters in sight at once. The Mososauria were essentially swimming lizards with four well-developed paddles, and they had little affinity with modern serpents, to which they have been compared.”

Or, again, notice the specimens of the genus Cidastes, which are also described as veritable sea-serpents of those ancient seas, whose huge bones and almost incredible number of vertebræ show them to have attained a length of nearly two hundred feet. The remains of no less than ten of these monsters were seen by Professor Mudge, while riding through the Mauvaise Terres of Colorado, strewn upon the plains, their whitened bones bleached in the suns of centuries, and their gaping jaws armed with ferocious teeth, telling a wonderful tale of their power when alive.

The same deposits have been equally fertile in the remains of terrestrial animals of gigantic size. The Titanosaurus montanus, believed to have been herbivorous, is estimated to have reached fifty or sixty feet in length; while other Dinosaurians of still more gigantic proportions, from the Jurassic beds of the Rocky Mountains, have been described by Professor Marsh. Among the discovered remains of Atlantosaurus immanis is a femur over six feet in length, and it is estimated from a comparison of this specimen with the same bone in living reptiles that this species, if similar in proportions to the crocodile, would have been over one hundred feet in length.

But even yet the limit has not been reached, and we hear of the discovery of the remains of another form, of such Titanic proportions as to possess a thigh-bone over twelve feet in length.

Fig. 5. – Monster bones of extinct gigantic Sauriansfrom Colorado, showing relative proportionsto corresponding bone in the Crocodile (A).

(From the “Scientific American.”)

From these considerations it is evident that, on account of the dimensions usually assigned to them, no discredit can be attached to the existence of the fabulous monsters of which we shall speak hereafter; for these, in the various myths, rarely or never equal in size creatures which science shows to have existed in a comparatively recent geological age, while the quaintest conception could hardly equal the reality of yet another of the American Dinosaurs, Stegosaurus, which appears to have been herbivorous, and more or less aquatic in habit, adapted for sitting upon its hinder extremities, and protected by bony plate and numerous spines. It reached thirty feet in length. Professor Marsh considers that this, when alive, must have presented the strangest appearance of all the Dinosaurs yet discovered.

The affinities of birds and reptiles have been so clearly demonstrated of late years, as to cause Professor Huxley and many other comparative anatomists to bridge over the wide gap which was formerly considered to divide the two classes, and to bracket them together in one class, to which the name Sauropsidæ has been given.³⁵

There are, indeed, not a few remarkable forms, as to the class position of which, whether they should be assigned to birds or reptiles, opinion was for a long time, and is in a few instances still, divided. It is, for example, only of late years that the fossil form Archæopteryx³⁶ (Fig. 4, p. 19) from the Solenhofen slates, has been definitely relegated to the former, but arguments against this disposal of it have been based upon the beak or jaws being furnished with true teeth, and the feather of the tail attached to a series of vertebræ, instead of a single flattened one as in birds. It appears to have been entirely plumed, and to have had a moderate power of flight.

Fig. 6. – Sivatherium (restored), from the Upper Miocenedeposits of the Siwalik Hills. (After Figuier.)

On the other hand, the Ornithopterus is only provisionally classed with reptiles, while the connection between the two classes is drawn still closer by the copious discovery of the birds from the Cretaceous formations of America, for which we are indebted to Professor Marsh.

The Lepidosiren, also, is placed mid-way between reptiles and fishes. Professor Owen and other eminent physiologists consider it a fish; Professor Bischoff and others, an amphibian reptile. It has a two-fold apparatus for respiration, partly aquatic, consisting of gills, and partly aerial, of true lungs.

So far, then, as abnormality of type is concerned, we have here instances quite as remarkable as those presented by most of the strange monsters with the creation of which mythological fancy has been credited.

Fig. 7. – Skeleton of Megatherium. (After Figuier.)

Among mammals I shall only refer to the Megatherium, which appears to have been created to burrow in the earth and to feed upon the roots of trees and shrubs, for which purpose every organ of its heavy frame was adapted. This Hercules among animals was as large as an elephant or rhinoceros of the largest species, and might well, as it has existed until a late date, have originated the myths, current among the Indians of South America, of a gigantic tunnelling or burrowing creature, incapable of supporting the light of day.³⁷

CHAPTER II.
EXTINCTION OF SPECIES

In reviewing the past succession of different forms of ancient life upon the globe, we are reminded of a series of dissolving views, in which each species evolves itself by an imperceptible gradation from some pre-existing one, arrives at its maximum of individuality, and then slowly fades away, while another type, either higher or lower, evolved in turn from it, emerges from obscurity, and succeeds it on the field of view.

Specific individuality has in all cases a natural term, dependent on physical causes, but that term is in many cases abruptly anticipated by a combination of unfavourable conditions.

Alteration of climate, isolation by geological changes, such as the submergence of continents and islands, and the competition of other species, are among the causes which have at all times operated towards its destruction; while, since the evolution of man, his agency, so far as we can judge by what we know of his later history, has been especially active in the same direction.

The limited distribution of many species, even when not enforced by insular conditions, is remarkable, and, of course, highly favourable to their destruction. A multiplicity of examples are familiar to naturalists, and possibly not a few may have attracted the attention of the ordinary observer.

For instance, it is probably generally known, that in our own island, the red grouse (which, by the way, is a species peculiar to Great Britain) is confined to certain moorlands, the ruffs and reeves to fen districts, and the nightingale,³⁸ chough, and other species to a few counties; while Ireland is devoid of almost all the species of reptiles common to Great Britain. In the former cases, the need of or predilection for certain foods probably determines the favourite locality, and there are few countries which would not furnish similar examples. In the latter, the explanation depends on biological conditions dating prior to the separation of Ireland from the main continent. Among birds, it might fairly be presumed that the power of flight would produce unlimited territorial expansion, but in many instances the reverse is found to be the case: a remarkable example being afforded by the island of Tasmania, a portion of which is called the unsettled waste lands, or Western Country. This district, which comprises about one-third of the island upon the western side, and is mainly composed of mountain chains of granites, quartzite, and mica schists, is entirely devoid of the numerous species of garrulous and gay-plumaged birds, such as the Mynah mocking-bird, white cockatoo, wattle bird, and Rosella parrot, though these abundantly enliven the eastern districts, which are fertilized by rich soils due to the presence of ranges of basalt, greenstone, and other trappean rocks.

Another equally striking instance is given by my late father, Mr. J. Gould, in his work on the humming-birds. Of two species, inhabiting respectively the adjacent mountains of Pichincha and Chimborazo at certain elevations, each is strictly confined to its own mountain; and, if my memory serves me correctly, he mentions similar instances of species peculiar to different peaks of the Andes.

Limitation by insular isolation is intelligible, especially in the case of mammals and reptiles, and of birds possessing but small power of flight; and we are, therefore, not surprised to find Mr. Gosse indicating, among other examples, that even the smallest of the Antilles has each a fauna of its own, while the humming-birds, some of the parrots, cuckoos, and pigeons, and many of the smaller birds are peculiar to Jamaica. He states still further, that in the latter instance many of the animals are not distributed over the whole island, but confined to a single small district.

Continental limitation is effected by mountain barriers. Thus, according to Mr. Wallace, almost all the mammalia, birds, and insects on one side of the Andes and Rocky Mountains are distinct in species from those on the other; while a similar difference, but smaller in degree, exists with reference to regions adjacent to the Alps and Pyrenees.

Climate, broad rivers, seas, oceans, forests, and even large desert wastes, like the Sahara or the great desert of Gobi, also act more or less effectively as girdles which confine species within certain limits.

Dependence on each other or on supplies of appropriate food also form minor yet practical factors in the sum of limitation; and a curious example of the first is given by Dr. Van Lennep with reference to the small migratory birds that are unable to perform the flight of three hundred and fifty miles across the Mediterranean. He states that these are carried across on the backs of cranes.³⁹

In the autumn many flocks of cranes may be seen coming from the North, with the first cold blast from that quarter, flying low, and uttering a peculiar cry, as if of alarm, as they circle over the cultivated plains. Little birds of every species may be seen flying up to them, while the twittering cries of those already comfortably settled upon their backs may be distinctly heard. On their return in the spring they fly high, apparently considering that their little passengers can easily find their way down to the earth.

The question of food-supply is involved in the more extended subject of geological structure, as controlling the flora and the insect life dependent on it. As an example we may cite the disappearance of the capercailzie from Denmark with the decay of the pine forests abundant during late Tertiary periods.

Collision, direct or indirect, with inimical species often has a fatal ending. Thus the dodo was exterminated by the swine which the early visitors introduced to the Mauritius and permitted to run wild there; while the indigenous insects, mollusca, and perhaps some of the birds of St. Helena, disappeared as soon as the introduction of goats caused the destruction of the whole flora of forest trees.

The Tsetse fly extirpates all horses, dogs, and cattle, from certain districts of South Africa, and a representative species in Paraguay is equally fatal to new-born cattle and horses.

Mr. Darwin⁴⁰ shows that the struggle is more severe between species of the same genus, when they come into competition with each other, than between species of distinct genera. Thus one species of swallow has recently expelled another from part of the United States; and the missel-thrush has driven the song-thrush from part of Scotland. In Australia the imported hive-bee is rapidly exterminating the small stingless native bee, and similar cases might be found in any number.

Mr. Wallace, in quoting Mr. Darwin as to these facts, points the conclusion that “any slight change, therefore, of physical geography or of climate, which allows allied species hitherto inhabiting distinct areas to come into contact, will often lead to the extermination of one of them.”

It is the province of the palæontologist to enumerate the many remarkable forms which have passed away since man’s first appearance upon the globe, and to trace their fluctuations over both hemispheres as determined by the advance and retreat of glacial conditions, and by the protean forms assumed by past and existing continents under oscillations of elevation and depression. Many interesting points, such as the dates of the successive separation of Ireland and Great Britain from the main continent, can be determined with accuracy from the record furnished by the fossil remains of animals of those times; and many interesting associations of animals with man at various dates, in our present island home and in other countries, have been traced by the discovery of their remains in connection with his, in bone deposits in caverns and elsewhere.

Conversely, most valuable deductions are drawn by the zoologist from the review which he is enabled to take, through the connected labours of his colleagues in all departments, of the distinct life regions now mapped out upon the face of the globe. These, after the application of the necessary corrections for various disturbing or controlling influences referred to above, afford proof reaching far back into past periods, of successive alterations in the disposition of continents and oceans, and of connections long since obliterated between distant lands.

The palæontologist reasons from the past to the present, the zoologist from the present to the past; and their mutual labours explain the evolution of existing forms, and the causes of the disparity or connection between those at present characterizing the different portions of the surface of the globe.

The palæontologist, for example, traces the descent of the horse, which, until its reintroduction by the Spaniards was unknown in the New World, through a variety of intermediate forms, to the genus Orohippus occurring in Eocene deposits in Utah and Wyoming. This animal was no larger than a fox, and possessed four separated toes in front, and three behind. Domestic cattle he refers to the Bos primigenius, and many existing Carnivora to Tertiary forms such as the cave-bear, cave-lion, sabre-tiger, and the like.

The zoologist groups the existing fauna into distinct provinces, and demands, in explanation of the anomalies which these exhibit, the reconstruction of large areas, of which only small outlying districts remain at the present date, in many instances widely separated by oceans, though once forming parts of the same continent; and so, for the simile readily suggests itself, the workers in another branch of science, Philology, argue from words and roots scattered like fossils through the various dialects of very distant countries, a mutual descent from a common Aryan language: the language of a race of which no historical record exists, though in regard to its habits, customs, and distribution much may be affirmed from the large collection of word specimens stored in philological museums.

Thus Mr. Sclater, on zoological grounds, claims the late existence of a continent which he calls Lemuria, extending from Madagascar to Ceylon and Sumatra; and for similar reasons Mr. Wallace extends the Australia of Tertiary periods to New Guinea and the Solomon Islands, and perhaps to Fiji, and from its marsupial types infers a connection with the northern continent during the Secondary period.

Again, the connection of Europe with North Africa during a late geological period is inferred by many zoologists from the number of identical species of mammalia inhabiting the opposite sides of the Mediterranean, and palæontologists confirm this by the discovery of the remains of elephants in cave-deposits in Malta, and of hippopotami in Gibraltar; while hydrographers furnish the supplemental suggestive evidence that an elevation of only fifteen hundred feet would be sufficient to establish two broad connections between the two continents – so as to unite Italy with Tripoli and Spain with Morocco, and to convert the Mediterranean Sea into two great lakes, which appears, in fact, to have been its condition during the Pliocene and Post Pliocene periods.

It was by means of these causeways that the large pachyderms entered Britain, then united to the continent; and it was over them they retreated when driven back by glacial conditions, their migration northward being effectually prevented by the destruction of the connecting arms of land.

Some difference of opinion exists among naturalists as to the extent to which zoological regions should be subdivided, and as to their respective limitations.

But Mr. A. R. Wallace, who has most recently written on the subject, is of opinion that the original division proposed by Mr. Sclater in 1857 is the most tenable, and he therefore adopts it in the very exhaustive work upon the geographical distribution of animals which he has recently issued. Mr. Sclater’s Six Regions are as follows: —

1. —The Palæarctic Region, including Europe, Temperate Asia, and North Africa to the Atlas mountains.

2. —The Ethiopian Region, Africa south of the Atlas, Madagascar, and the Mascarene islands, with Southern Arabia.

3. —The Indian Region, including India south of the Himalayas, to South China, and to Borneo and Java.

4. —The Australian Region, including Celebes and Lombok, Eastward to Australia and the Pacific islands.

5. —The Nearctic Region, including Greenland, and North America, to Northern Mexico.

6. —The Neotropical Region, including South America, the Antilles, and Southern Mexico.

This arrangement is based upon a detailed examination of the chief genera and families of birds, and also very nearly represents the distribution of mammals and of reptiles. Its regions are not, as in other subsequently proposed and more artificial systems, controlled by climate; for they range, in some instances, from the pole to the tropics. It probably approaches more nearly than any other yet proposed to that desideratum, a division of the earth into regions, founded on a collation of the groups of forms indigenous to or typical of them, and upon a selection of those peculiar to them; with a disregard of, or only admitting with caution, any which, though common to and apparently establishing connection between two or more regions, may have in fact but little value for the purpose of such comparison; from the fact of its being possible to account for their extended range by their capability of easy transport from one region to another by common natural agencies.⁴¹