text:
Page:Darwinism by Alfred Wallace 1889.djvu/302

 exposed to the attack of the whole colony; whereas a hawk or falcon could carry off a sitting-bird or the young at a swoop, and entirely avoid attack. Moreover, each kind of covered nest is doubtless directed against the attacks of the most dangerous enemies of the species, the purse-like nests, often a yard long, suspended from the extremity of thin twigs, being useful against the attacks of snakes, which, if they attempted to enter them, would be easily made to lose their hold and fall to the ground. Such birds as jays, crows, magpies, hawks, and other birds of prey, have also been urged as an exception; but these are all aggressive birds, able to protect themselves, and thus do not need any special protection for their females during nidification. Some birds which build in covered nests are comparatively dull coloured, like many of the weaver birds, but in others the colours are more showy, and in all the sexes are alike; so that none of these are in any way opposed to the rule. The golden orioles have, however, been adduced as a decided exception, since the females are showy and build in an open nest. But even here the females are less brilliant than the males, and are sometimes greenish or olivaceous on the upper surface; while they very carefully conceal their nests among dense foliage, and the male is sufficiently watchful and pugnacious to drive off most intruders.

On the other hand, how remarkable it is that the only small and brightly coloured birds of our own country in which the male and female are alike—the tits and starlings—either build in holes or construct covered nests; while the beautiful hangnests (Icteridae) of South America, which always build covered or purse-shaped nests, are equally showy in both sexes, in striking contrast with the chatterers and tanagers of the same country, whose females are invariably less conspicuous than the males. On a rough estimate, there are about 1200 species of birds in the class of showy males and females, with concealed nidification; while there are probably, from an equally rough estimate, about the same number in the contrasted class of showy males and dull females, with open nests. This will leave the great bulk of known birds in the classes of those which are more or less protectively coloured in both sexes; or which, from their organisation and habits, do


text:
Page:Darwinism by Alfred Wallace 1889.djvu/303

 not require special protective coloration, such as many of the birds of prey, the larger waders, and the oceanic birds.

There are a few very curious cases in which the female bird is actually more brilliant than the male, and which yet have open nests. Such are the dotterel (Eudromias morinellus), several species of phalarope, an Australian creeper (Climacteris erythropus), and a few others; but in every one of these cases the relation of the sexes in regard to nidification is reversed, the male performing the duties of incubation, while the female is the stronger and more pugnacious. This curious case, therefore, quite accords with the general law of coloration.

We may consider a few of the cases of sexual colouring of other classes of vertebrates, as given by Mr. Darwin. In fishes, though the sexes are usually alike, there are several species in which the males are more brightly coloured, and have more elongated fins, spines, or other appendages, and in some few cases the colours are decidedly different. The males often fight together, and are altogether more vivacious and excitable than the females during the breeding season; and with this we may connect a greater intensity of coloration.

In frogs and toads the colours are usually alike, or a little more intense in the males, and the same may be said of most snakes. It is in lizards that we first meet with considerable sexual differences, many of the species having gular pouches, frills, dorsal crests, or horns, either confined to the males, or more developed in them than in the females, and these ornaments are often brightly coloured. In most cases, however, the tints of lizards are protective, the male being usually a little more intense in coloration; and the difference in extreme cases may be partly due to the need of protection for the female, which, when laden with eggs, must be less active and less able to escape from enemies than the male, and may, therefore, have retained more protective colours, as so many insects and birds have certainly done.

In mammalia there is often a somewhat greater intensity

license: Creative Commons - Attribution Share-Alike - https://creativecommons.org/licenses/by-sa/4.0/


text:
Page:Darwinism by Alfred Wallace 1889.djvu/304

 of colour in the male, but rarely a decided difference. The female of the great red kangaroo, however, is a delicate gray; while in the Lemur macaco of Madagascar the male is jet-black and the female brown. In many monkeys also there are some differences of colour, especially on the face. The sexual weapons and ornaments of male mammalia, as horns, crests, manes, and dewlaps, are well known, and are very numerous and remarkable. Having thus briefly reviewed the facts, we will now consider the theories to which they have given rise.

Among the higher animals it is a very general fact that the males fight together for the possession of the females. This leads, in polygamous animals especially, to the stronger or better armed males becoming the parents of the next generation, which inherits the peculiarities of the parents; and thus vigour and offensive weapons are continually increased in the males, resulting in the strength and horns of the bull, the tusks of the boar, the antlers of the stag, and the spurs and fighting instinct of the gamecock. But almost all male animals fight together, though not specially armed; even hares, moles, squirrels, and beavers fight to the death, and are often found to be scarred and wounded. The same rule applies to almost all male birds; and these battles have been observed in such different groups as humming-birds, finches, goatsuckers, woodpeckers, ducks, and waders. Among reptiles, battles of the males are known to occur in the cases of crocodiles, lizards, and tortoises; among fishes, in those of salmon and sticklebats. Even among insects the same law prevails; and male spiders, beetles of many groups, crickets, and butterflies often fight together.

From this very general phenomenon there necessarily results a form of natural selection which increases the vigour and fighting power of the male animal, since, in every case, the weaker are either killed, wounded, or driven away. This selection would be more powerful if males were always in excess of females, but after much research Mr. Darwin could not obtain any satisfactory evidence that this was the case. The same effect, however, is produced in some cases by constitution or habits; thus male insects usually emerge first from


text:
Page:Darwinism by Alfred Wallace 1889.djvu/305

 the pupa, and among migrating birds the males arrive first both in this country and in North America. The struggle is thus intensified, and the most vigorous males are the first to have offspring. This in all probability is a great advantage, as the early breeders have the start in securing food, and the young are strong enough to protect themselves while the later broods are being produced.

It is to this form of male rivalry that Mr. Darwin first applied the term "sexual selection." It is evidently a real power in nature; and to it we must impute the development of the exceptional strength, size, and activity of the male, together with the possession of special offensive and defensive weapons, and of all other characters which arise from the development of these or are correlated with them. But he has extended the principle into a totally different field of action, which has none of that character of constancy and of inevitable result that attaches to natural selection, including male rivalry; for by far the larger portion of the phenomena, which he endeavours to explain by the direct action of sexual selection, can only be so explained on the hypothesis that the immediate agency is female choice or preference. It is to this that he imputes the origin of all secondary sexual characters other than weapons of offence and defence, of all the ornamental crests and accessory plumes of birds, the stridulating sounds of insects, the crests and beards of monkeys and other mammals, and the brilliant colours and patterns of male birds and butterflies. He even goes further, and imputes to it a large portion of the brilliant colour that occurs in both sexes, on the principle that variations occurring in one sex are sometimes transmitted to the same sex only, sometimes to both, owing to peculiarities in the laws of inheritance. In this extension of sexual selection to include the action of female choice or preference, and in the attempt to give to that choice such wide-reaching effects, I am unable to follow him more than a very little way; and I will now state some of the reasons why I think his views are unsound.

Besides the acquisition of weapons by the male for the purpose of fighting with other males, there are some other


text:
Page:Darwinism by Alfred Wallace 1889.djvu/306

 sexual characters which may have been produced by natural selection. Such are the various sounds and odours which are peculiar to the male, and which serve as a call to the female or as an indication of his presence. These are evidently a valuable addition to the means of recognition of the two sexes, and are a further indication that the pairing season has arrived; and the production, intensification, and differentiation of these sounds and odours are clearly within the power of natural selection. The same remark will apply to the peculiar calls of birds, and even to the singing of the males. These may well have originated merely as a means of recognition between the two sexes of a species, and as an invitation from the male to the female bird. When the individuals of a species are widely scattered, such a call must be of great importance in enabling pairing to take place as early as possible, and thus the clearness, loudness, and individuality of the song becomes a useful character, and therefore the subject of natural selection. Such is especially the case with the cuckoo, and with all solitary birds, and it may have been equally important at some period of the development of all birds. The act of singing is evidently a pleasurable one; and it probably serves as an outlet for superabundant nervous energy and excitement, just as dancing, singing, and field sports do with us. It is suggestive of this view that the exercise of the vocal power seems to be complementary to the development of accessory plumes and ornaments, all our finest singing birds being plainly coloured, and with no crests, neck or tail plumes to display; while the gorgeously ornamented birds of the tropics have no song, and those which expend much energy in display of plumage, as the turkey, peacocks, birds of paradise, and humming-birds, have comparatively an insignificant development of voice. Some birds have, in the wings or tail, peculiarly developed feathers which produce special sounds. In some of the little manakins of Brazil, two or three of the wing-feathers are curiously shaped and stiffened in the male, so that the bird is able to produce with them a peculiar snapping or cracking sound; and the tail-feathers of several species of snipe are so narrowed as to produce distinct drumming, whistling, or switching sounds when the birds


text:
Page:Darwinism by Alfred Wallace 1889.djvu/307

 descend rapidly from a great height. All these are probably recognition and call notes, useful to each species in relation to the most important function of their lives, and thus capable of being developed by the agency of natural selection.

Mr. Darwin has devoted four chapters of his Descent of Man to the colours of birds, their decorative plumage, and its display at the pairing season; and it is on this latter circumstance that he founds his theory, that both the plumage and the colours have been developed by the preference of the females, the more ornamented males becoming the parents of each successive generation. Any one who reads these most interesting chapters will admit, that the fact of the display is demonstrated; and it may also be admitted, as highly probable, that the female is pleased or excited by the display. But it by no means follows that slight differences in the shape, pattern, or colours of the ornamental plumes are what lead a female to give the preference to one male over another; still less that all the females of a species, or the great majority of them, over a wide area of country, and for many successive generations, prefer exactly the same modification of the colour or ornament.

The evidence on this matter is very scanty, and in most cases not at all to the point. Some peahens preferred an old pied peacock; albino birds in a state of nature have never been seen paired with other birds; a Canada goose paired with a Bernicle gander; a male widgeon preferred a pintail duck to its own species; a hen canary preferred a male greenfinch to either linnet, goldfinch, siskin, or chaffinch. These cases are evidently exceptional, and are not such as generally occur in nature; and they only prove that the female does exert some choice between very different males, and some observations on birds in a state of nature prove the same thing; but there is no evidence that slight variations in the colour or plumes, in the way of increased intensity or complexity, are what determines the choice. On the other hand, Mr. Darwin gives much evidence that it is not so determined. He tells us that Messrs. Hewitt, Tegetmeier, and Brent, three of the highest authorities and best observers, "do not believe that


text:
Page:Darwinism by Alfred Wallace 1889.djvu/308

 the females prefer certain males on account of the beauty of their plumage." Mr. Hewitt was convinced "that the female almost invariably prefers the most vigorous, defiant, and mettlesome male;" and Mr. Tegetmeier, "that a gamecock, though disfigured by being dubbed, and with his hackles trimmed, would be accepted as readily as a male retaining all his natural ornaments." Evidence is adduced that a female pigeon will sometimes take an antipathy to a particular male without any assignable cause; or, in other cases, will take a strong fancy to some one bird, and will desert her own mate for him; but it is not stated that superiority or inferiority of plumage has anything to do with these fancies. Two instances are indeed given, of male birds being rejected, which had lost their ornamental plumage; but in both cases (a widow-finch and a silver pheasant) the long tail-plumes are the indication of sexual maturity. Such cases do not support the idea that males with the tail-feathers a trifle longer, or the colours a trifle brighter, are generally preferred, and that those which are only a little inferior are as generally rejected,—and this is what is absolutely needed to establish the theory of the development of these plumes by means of the choice of the female.

It will be seen, that female birds have unaccountable likes and dislikes in the matter of their partners, just as we have ourselves, and this may afford us an illustration. A young man, when courting, brushes or curls his hair, and has his moustache, beard, or whiskers in perfect order, and no doubt his sweetheart admires them; but this does not prove that she marries him on account of these ornaments, still less that hair, beard, whiskers, and moustache were developed by the continued preferences of the female sex. So, a girl likes to see her lover well and fashionably dressed, and he always dresses as well as he can when he visits her; but we cannot conclude from this that the whole series of male costumes, from the brilliantly coloured, puffed, and slashed doublet and hose of the Elizabethan period, through the gorgeous coats, long waistcoats, and pigtails of the early Georgian era, down to the funereal dress-suit of the present day, are the direct result of female preference. In like manner, female birds may be


text:
Page:Darwinism by Alfred Wallace 1889.djvu/309

 charmed or excited by the fine display of plumage by the males; but there is no proof whatever that slight differences in that display have any effect in determining their choice of a partner.

The extraordinary manner in which most birds display their plumage at the time of courtship, apparently with the full knowledge that it is beautiful, constitutes one of Mr. Darwin's strongest arguments. It is, no doubt, a very curious and interesting phenomenon, and indicates a connection between the exertion of particular muscles and the development of colour and ornament; but, for the reasons just given, it does not prove that the ornament has been developed by female choice. During excitement, and when the organism develops superabundant energy, many animals find it pleasurable to exercise their various muscles, often in fantastic ways, as seen in the gambols of kittens, lambs, and other young animals. But at the time of pairing, male birds are in a state of the most perfect development, and possess an enormous store of vitality; and under the excitement of the sexual passion they perform strange antics or rapid flights, as much probably from an internal impulse to motion and exertion as with any desire to please their mates. Such are the rapid descent of the snipe, the soaring and singing of the lark, and the dances of the cock-of-the-rock and of many other birds.

It is very suggestive that similar strange movements are performed by many birds which have no ornamental plumage to display. Goatsuckers, geese, carrion vultures, and many other birds of plain plumage have been observed to dance, spread their wings or tails, and perform strange love-antics. The courtship of the great albatross, a most unwieldy and dull coloured bird, has been thus described by Professor Moseley: "The male, standing by the female on the nest, raises his wings, spreads his tail and elevates it, throws up his head with the bill in the air, or stretches it straight out, or forwards, as far as he can, and then utters a curious cry." Mr. Jenner Weir informs me that "the male blackbird is full of action, spreads out his glossy wing and tail, turns his rich golden


text:
Page:Darwinism by Alfred Wallace 1889.djvu/310

 beak towards the female, and chuckles with delight," while he has never seen the more plain coloured thrush demonstrative to the female. The linnet distends his rosy breast, and slightly expands his brown wings and tail; while the various gay coloured Australian finches adopt such attitudes and postures as, in every case, to show off their variously coloured plumage to the best advantage.

Having rejected Mr. Darwin's theory of female choice as incompetent to account for the brilliant colours and markings of the higher animals, the preponderance of these colours and markings in the male sex, and their display during periods of activity or excitement, I may be asked what explanation I have to offer as a preferable substitute. In my Tropical Nature I have already indicated such a theory, which I will now briefly explain, supporting it by some additional facts and arguments, which appear to me to have great weight, and for which I am mainly indebted to a most interesting and suggestive posthumous work by Mr. Alfred Tylor.

The fundamental or ground colours of animals are, as has been shown in preceding chapters, very largely protective, and it is not improbable that the primitive colours of all animals were so. During the long course of animal development other modes of protection than concealment by harmony of colour arose, and thenceforth the normal development of colour due to the complex chemical and structural changes ever going on in the organism, had full play; and the colours thus produced were again and again modified by natural selection for purposes of warning, recognition, mimicry, or special protection, as has been already fully explained in the preceding chapters.

Mr. Taylor has, however, called attention to an important principle which underlies the various patterns or ornamental markings of animals—namely, that diversified coloration follows the chief lines of structure, and changes at points, such as the joints, where function changes. He says, "If we take highly decorated species—that is, animals marked by


text:
Page:Darwinism by Alfred Wallace 1889.djvu/311

 alternate dark or light bands or spots, such as the zebra, some deer, or the carnivora, we find, first, that the region of the spinal column is marked by a dark stripe; secondly, that the regions of the appendages, or limbs, are differently marked; thirdly, that the flanks are striped or spotted, along or between the regions of the lines of the ribs; fourthly, that the shoulder and hip regions are marked by curved lines; fifthly, that the pattern changes, and the direction of the lines, or spots, at the head, neck, and every joint of the limbs; and lastly, that the tips of the ears, nose, tail, and feet, and the eye are emphasised in colour. In spotted animals the greatest length of the spot is generally in the direction of the largest development of the skeleton."

This structural decoration is well seen in many insects. In caterpillars, similar spots and markings are repeated in each segment, except where modified for some form of protection. In butterflies, the spots and bands usually have reference to the form of the wing and the arrangement of the nervures; and there is much evidence to show that the primitive markings are always spots in the cells, or between the nervures, or at the junctions of nervures, the extension and coalescence of these spots forming borders, bands, or blotches, which have become modified in infinitely varied ways for protection, warning, or recognition. Even in birds, the distribution of colours and markings follows generally the same law. The crown of the head, the throat, the ear-coverts, and the eyes have usually distinct tints in all highly coloured birds; the region of the furcula has often a distinct patch of colour, as have the pectoral muscles, the uropygium or root of the tail, and the under tail-coverts.

Mr. Tylor was of opinion the primitive form of ornamentation consisted of spots, the confluence of these in certain directions forming lines or bands; and, these again, sometimes coalescing into blotches, or into more or less uniform tints covering a large portion of the surface of the body. The young lion and tiger are both spotted; and in the Java hog (Sus vittatus) very young animals are banded, but have spots over the shoulders and thighs. These spots run into stripes


text:
Page:Darwinism by Alfred Wallace 1889.djvu/312

 as the animal grows older; then the stripes expand, and at last, meeting together, the adult animal becomes of a uniform dark brown colour. So many of the species of deer are spotted when young, that Darwin concludes the ancestral form, from which all deer are derived, must have been spotted. Pigs and tapirs are banded or spotted when young; an imported young specimen of Tapirus Bairdi was covered with white spots in longitudinal rows, here and there forming short stripes. Even the horse, which Darwin supposes to be descended from a striped animal, is often spotted, as in dappled horses; and great numbers show a tendency to spottiness, especially on the haunches.

Ocelli may also be developed from spots, or from bars, as pointed out by Mr. Darwin. Spots are an ordinary form of marking in disease, and these spots sometimes run together, forming blotches. There is evidence that colour markings are in some way dependent on nerve distribution. In the disease known as frontal herpes, an eruption occurs which corresponds exactly to the distribution of the ophthalmic division of the fifth cranial nerve, mapping out all its little branches even to the one which goes to the tip of the nose. In a Hindoo suffering from herpes the pigment was destroyed in the arm along the course of the ulnar nerve, with its branches along both sides of one finger and the half of another. In the leg the sciatic and scaphenous nerves were partly mapped out, giving to the patient the appearance of an anatomical diagram.

These facts are very interesting, because they help to explain the general dependence of marking on structure which has been already pointed out. For, as the nerves everywhere follow the muscles, and these are attached to the various bones, we see how it happens, that the tracts in which distinct developments of colour appear, should so often be marked out by the chief divisions of the bony structure in vertebrates, and by the segments in the annulosa. There is, however, another correspondence of even greater interest and importance. Brilliant colours usually appear just in proportion to the


text:
Page:Darwinism by Alfred Wallace 1889.djvu/313

 development of tegumentary appendages. Among birds the most brilliant colours are possessed by those which have developed frills, crests, and elongated tails like the humming-birds; immense tail-coverts like the peacock; enormously expanded wing-feathers, as in the argus-pheasant; or magnificent plumes from the region of the coracoids in many of the birds of paradise. It is to be noted, also, that all these accessory plumes spring from parts of the body which, in other species, are distinguished by patches of colour; so that we may probably impute the development of colour and of accessory plumage to the same fundamental cause.

Among insects, the most brilliant and varied coloration occurs in the butterflies and moths, groups in which the wing-membranes have received their greatest expansion, and whose specialisation has been carried furthest in the marvellous scaly covering which is the seat of the colour. It is suggestive, that the only other group in which functional wings are much coloured is that of the dragonflies, where the membrane is exceedingly expanded. In like manner, the colours of beetles, though greatly inferior to those of the lepidoptera, occur in a group in which the anterior pair of wings has been thickened and modified in order to protect the vital parts, and in which these wing-covers (elytra), in the course of development in the different groups, must have undergone great changes, and have been the seat of very active growth.

Mr. Darwin supposes, that these have in almost every case been developed by the preference of female birds for such males as possessed them in a higher degree than others; but this theory does not account for the fact that these plumes usually appear in a few definite parts of the body. We require some cause to initiate the development in one part rather than in another. Now, the view that colour has arisen over surfaces where muscular and nervous development is considerable, and the fact that it appears especially upon the accessory or highly developed plumes, leads us to inquire whether the same cause has not primarily determined the development of these plumes. The immense tuft of golden plumage in the best known birds of paradise (Paradisea apoda and P. minor)


text:
Page:Darwinism by Alfred Wallace 1889.djvu/314

 springs from a very small area on the side of the breast. Mr. Frank E. Beddard, who has kindly examined a specimen for me, says that "this area lies upon the pectoral muscles, and near to the point where the fibres of the muscle converge towards their attachment to the humerus. The plumes arise, therefore, close to the most powerful muscle of the body, and near to where the activities of that muscle would be at a maximum. Furthermore, the area of attachment of the plumes is just above the point where the arteries and nerves for the supply of the pectoral muscles, and neighbouring regions, leave the interior of the body. The area of attachment of the plume is, also, as you say in your letter, just above the junction of the coracoid and sternum." Ornamental plumes of considerable size rise from the same part in many other species of paradise birds, sometimes extending laterally in front, so as to form breast shields. They also occur in many humming-birds, and in some sun-birds and honey-suckers; and in all these cases there is a wonderful amount of activity and rapid movement, indicating a surplus of vitality, which is able to manifest itself in the development of these accessory plumes.

In a quite distinct set of birds, the gallinaceae, we find the ornamental plumage usually arising from very different parts, in the form of elongated tail-feathers or tail-coverts, and of ruffs or hackles from the neck. Here the wings are comparatively little used, the most constant activities depending on the legs, since the gallinaceae are pre-eminently walking, running, and scratching birds. Now the magnificent train of the peacock—the grandest development of accessory plumes in this order—springs from an oval or circular area, about three inches in diameter, just above the base of the tail, and, therefore, situated over the lower part of the spinal column near the insertion of the powerful muscles which move the hind limbs and elevate the tail. The very frequent presence of neck-ruffs or breast-shields in the males of birds with accessory plumes may be partly due to selection, because they must serve as a protection in their mutual combats, just as does the lion's or the horse's mane. The enormously lengthened plumes of the bird of paradise and of the peacock can, however, have no such use,


text:
Page:Darwinism by Alfred Wallace 1889.djvu/315

 but must be rather injurious than beneficial in the bird's ordinary life. The fact that they have been developed to so great an extent in a few species is an indication of such perfect adaptation to the conditions of existence, such complete success in the battle for life, that there is, in the adult male at all events, a surplus of strength, vitality, and growth-power which is able to expend itself in this way without injury. That such is the case is shown by the great abundance of most of the species which possess these wonderful superfluities of plumage. Birds of paradise are among the commonest birds in New Guinea, and their loud voices can be often heard when the birds themselves are invisible in the depths of the forest; while Indian sportsmen have described the peafowl as being so abundant, that from twelve to fifteen hundred have been seen within an hour at one spot; and they range over the whole country from the Himalayas to Ceylon. Why, in allied species, the development of accessory plumes has taken different forms, we are unable to say, except that it may be due to that individual variability which has served as the starting-point for so much of what seems to us strange in form, or fantastic in colour, both in the animal and vegetable world.

If we have found a vera causa for the origin of ornamental appendages of birds and other animals in a surplus of vital energy, leading to abnormal growths in those parts of the integument where muscular and nervous action are greatest, the continuous development of these appendages will result from the ordinary action of natural selection in preserving the most healthy and vigorous individuals, and the still further selective agency of sexual struggle in giving to the very strongest and most energetic the parentage of the next generation. And, as all the evidence goes to show that, so far as female birds exercise any choice, it is of "the most vigorous, defiant, and mettlesome male," this form of sexual selection will act in the same direction, and help to carry on the process of plume development to its culmination. That culmination will be reached when the excessive length or abundance of the plumes begins to be injurious to the bearer of them; and it may be this check to the further lengthening of the peacock's


text:
Page:Darwinism by Alfred Wallace 1889.djvu/316

 train that has led to the broadening of the feathers at the ends, and the consequent production of the magnificent eye-spots which now form its crowning ornament.

The display of these plumes will result from the same causes which led to their production. Just in proportion as the feathers themselves increased in length and abundance, the skin-muscles which serve to elevate them would increase also; and the nervous development as well as the supply of blood to these parts being at a maximum, the erection of the plumes would become a habit at all periods of nervous or sexual excitement. The display of the plumes, like the existence of the plumes themselves, would be the chief external indication of the maturity and vigour of the male, and would, therefore, be necessarily attractive to the female. We have, thus, no reason for imputing to her any of those aesthetic emotions which are excited in us, by the beauty of form, colour, and pattern of these plumes; or the still more improbable aesthetic tastes, which would cause her to choose her mate on account of minute differences in their forms, colours, or patterns.

As co-operating causes in the production of accessory ornamental plumes, I have elsewhere suggested that crests and other erectile feathers may have been useful in making the bird more formidable in appearance, and thus serving to frighten away enemies; while long tail or wing feathers might serve to distract the aim of a bird of prey. But though this might be of some use in the earlier stages of their development, it is probably of little importance compared with the vigour and pugnacity of which the plumes are the indication, and which enable most of their possessors to defend themselves against the enemies which are dangerous to weaker and more timid birds. Even the tiny humming-birds are said to attack birds of prey that approach too near to their nests.

The various facts and arguments now briefly set forth, afford an explanation of the phenomena of male ornament,


text:
Page:Darwinism by Alfred Wallace 1889.djvu/317

 as being due to the general laws of growth and development, and make it unnecessary to call to our aid so hypothetical a cause as the cumulative action of female preference. There remains, however, a general argument, arising from the action of natural selection itself, which renders it almost inconceivable that female preference could have been effective in the way suggested; while the same argument strongly supports the view here set forth. Natural selection, as we have seen in our earlier chapters, acts perpetually and on an enormous scale in weeding out the "unfit" at every stage of existence, and preserving only those which are in all respects the very best. Each year, only a small percentage of young birds survive to take the place of the old birds which die; and the survivors will be those which are best able to maintain existence from the egg onwards, an important factor being that their parents should be well able to feed and protect them, while they themselves must in turn be equally able to feed and protect their own offspring. Now this extremely rigid action of natural selection must render any attempt to select mere ornament utterly nugatory, unless the most ornamented always coincide with "the fittest" in every other respect; while, if they do so coincide, then any selection of ornament is altogether superfluous. If the most brightly coloured and fullest plumaged males are not the most healthy and vigorous, have not the best instincts for the proper construction and concealment of the nest, and for the care and protection of the young, they are certainly not the fittest, and will not survive, or be the parents of survivors. If, on the other hand, there is generally this correlation—if, as has been here argued, ornament is the natural product and direct outcome of superabundant health and vigour, then no other mode of selection is needed to account for the presence of such ornament. The action of natural selection does not indeed disprove the existence of female selection of ornament as ornament, but it renders it entirely ineffective; and as the direct evidence for any such female selection is almost nil, while the objections to it are certainly weighty, there can be no longer any reason for upholding a theory which was provisionally useful in calling attention to a most curious and suggestive body of facts, but which is now no longer tenable.


text:
Page:Darwinism by Alfred Wallace 1889.djvu/318

 The term "sexual selection" must, therefore, be restricted to the direct results of male struggle and combat. This is really a form of natural selection, and is a matter of direct observation; while its results are as clearly deducible as those of any of the other modes in which selection acts. And if this restriction of the term is needful in the case of the higher animals it is much more so with the lower. In butterflies the weeding out by natural selection takes place to an enormous extent in the egg, larva, and pupa states; and perhaps not more than one in a hundred of the eggs laid produces a perfect insect which lives to breed. Here, then, the impotence of female selection, if it exist, must be complete; for, unless the most brilliantly coloured males are those which produce the best protected eggs, larvae, and pupae, and unless the particular eggs, larvae, and pupae, which are able to survive, are those which produce the most brilliantly coloured butterflies, any choice the female might make must be completely swamped. If, on the other hand, there is this correlation between colour development and perfect adaptation to conditions in all stages, then this development will necessarily proceed by the agency of natural selection and the general laws which determine the production of colour and of ornamental appendages.

The condensed account which has now been given of the phenomena of colour in the animal world will sufficiently show the wonderful complexity and extreme interest of the subject; while it affords an admirable illustration of the importance of the great principle of utility, and of the effect of the theories of natural selection and development in giving a new interest


text:
Page:Darwinism by Alfred Wallace 1889.djvu/319

 to the most familiar facts of nature. Much yet remains to be done, both in the observation of new facts as to the relations between the colours of animals and their habits or economy, and, more especially, in the elucidation of the laws of growth which determine changes of colour in the various groups; but so much is already known that we are able, with some confidence, to formulate the general principles which have brought about all the beauty and variety of colour which everywhere delight us in our contemplation of animated nature. A brief statement of these principles will fitly conclude our exposition of the subject.

1. Colour may be looked upon as a necessary result of the highly complex chemical constitution of animal tissues and fluids. The blood, the bile, the bones, the fat, and other tissues have characteristic, and often brilliant colours, which we cannot suppose to have been determined for any special purpose, as colours, since they are usually concealed. The external organs, with their various appendages and integuments, would, by the same general laws, naturally give rise to a greater variety of colour.

2. We find it to be the fact that colour increases in variety and intensity as external structures and dermal appendages become more differentiated and developed. It is on scales, hair, and especially on the more highly specialised feathers, that colour is most varied and beautiful; while among insects colour is most fully developed in those whose wing membranes are most expanded, and, as in the lepidoptera, are clothed with highly specialised scales. Here, too, we find an additional mode of colour production in transparent lamellae or in fine surface striae which, by the laws of interference, produce the wonderful metallic hues of so many birds and insects.


text:
Page:Darwinism by Alfred Wallace 1889.djvu/320

 3. There are indications of a progressive change of colour, perhaps in some definite order, accompanying the development of tissues or appendages. Thus spots spread and fuse into bands, and when a lateral or centrifugal expansion has occurred—as in the termination of the peacocks' train feathers, the outer web of the secondary quills of the Argus pheasant, or the broad and rounded wings of many butterflies—into variously shaded or coloured ocelli. The fact that we find gradations of colour in many of the more extensive groups, from comparatively dull or simple to brilliant and varied hues, is an indication of some such law of development, due probably to progressive local segregation in the tissues of identical chemical or organic molecules, and dependent on laws of growth yet to be investigated.

4. The colours thus produced, and subject to much individual variation, have been modified in innumerable ways for the benefit of each species. The most general modification has been in such directions as to favour concealment when at rest in the usual surroundings of the species, sometimes carried on by successive steps till it has resulted in the most minute imitation of some inanimate object or exact mimicry of some other animal. In other cases bright colours or striking contrasts have been preserved, to serve as a warning of inedibility or of dangerous powers of attack. Most frequent of all has been the specialisation of each distinct form by some tint or marking for purposes of easy recognition, especially in the case of gregarious animals whose safety largely depends upon association and mutual defence.

5. As a general rule the colours of the two sexes are alike; but in the higher animals there appears a tendency to deeper or more intense colouring in the male, due probably to his greater vigour and excitability. In many groups in which this superabundant vitality is at a maximum, the development of dermal appendages and brilliant colours has gone on increasing till it has resulted in a great diversity between the sexes; and in most of these cases there is evidence to show that natural selection has caused the female to retain the primitive and more sober colours of the group for purposes of protection.


text:
Page:Darwinism by Alfred Wallace 1889.djvu/321

The general principles of colour development now sketched out enable us to give some rational explanation of the wonderful amount of brilliant colour which occurs among tropical animals. Looking on colour as a normal product of organisation, which has either been allowed free play, or has been checked and modified for the benefit of the species, we can see at once that the luxuriant and perennial vegetation of the tropics, by affording much more constant means of concealment, has rendered brilliant colour less hurtful there than in the temperate and colder regions. Again, this perennial vegetation supplies abundance of both vegetable and insect food throughout the year, and thus a greater abundance and greater variety of the forms of life are rendered possible, than where recurrent seasons of cold and scarcity reduce the possibilities of life to a minimum. Geology furnishes us with another reason, in the fact, that throughout the tertiary period tropical conditions prevailed far into the temperate regions, so that the possibilities of colour development were still greater than they are at the present time. The tropics, therefore, present to us the results of animal development in a much larger area and under more favourable conditions than prevail to-day. We see in them samples of the productions of an earlier and a better world, from an animal point of view; and this probably gives a greater variety and a finer display of colour than would have been produced, had conditions always been what they are now. The temperate zones, on the other hand, have recently suffered the effects of a glacial period of extreme severity, with the result that almost the only gay coloured birds they now possess are summer visitors from tropical or sub-tropical lands. It is to the unbroken and almost unchecked course of development from remote geological times that has prevailed in the tropics, favoured by abundant food and perennial shelter, that we owe such superb developments as the frills and crests and jewelled shields of the humming-birds, the golden plumes of the birds of paradise, and the resplendent train of the peacock. This last exhibits to us the culmination of that marvel and mystery of animal colour which is so well expressed by a poet-artist in the following


text:
Page:Darwinism by Alfred Wallace 1889.djvu/322

 lines. The marvel will ever remain to the sympathetic student of nature, but I venture to hope that in the preceding chapters I have succeeded in lifting—if only by one of its corners—the veil of mystery which has for long shrouded this department of nature.

In Nature's workshop but a shaving,
 * Of her poem but a word,

But a tint brushed from her palette,
 * This feather of a bird!

Yet set it in the sun glance,
 * Display it in the shine,

Take graver's lens, explore it,
 * Note filament and line,

Mark amethyst to sapphire,
 * And sapphire to gold,

And gold to emerald changing
 * The archetype unfold!

Tone, tint, thread, tissue, texture,
 * Through every atom scan,

Conforming still, developing,
 * Obedient to plan.

This but to form a pattern
 * On the garment of a bird!

What then must be the poem,
 * This but its lightest word!

Sit before it; ponder o'er it,
 * 'Twill thy mind advantage more,

Than a treatise, than a sermon,
 * Than a library of lore.


text:
The Natural History of Ireland/Volume 1/The Belted Kingfisher

BELTED KINGFISHER.

Alcedo alcyon, Linn.

Two individuals of this species have been met with about the same period.

They were thus noticed in a communication which I made to the Annals of Natural History, for December, 1845. "I have the pleasure to record the occurrence of this North American bird in Ireland; a specimen (as I learn by letter from T. W. Warren, Esq., of Dublin, dated Nov. 21, 1845,) having been shot by Frederick A. Smith, Esq., at Annsbrook, county of Meath, on the 26th of October last. It has fortunately been preserved, and on being shown to Mr. R. Ball, was identified as A. Alcyon : this gentle- man considers that the full strong plumage of the specimen denotes a truly wild bird, and not an individual that had escaped from confinement. According to the descriptions of Wilson and Richardson, it is a female, and not, at all events, in younger plumage, than that of the second year. Mr. Warren adds, that when at the shop of Mr. Glennon, the well-known bird- preserver, on the day before the date of his letter, the gamekeeper of Mr. Latouche of Luggela, county of Wicklow, called to mention that he had, within the last few days, seen a very large kingfisher, at a stream connecting the lake of Luggela with Lough Dan. He saw the bird very well, as it admitted of his approach within twenty yards : his description agreeing with the A. Alcyon, the specimen was shown to him, and he at once identified his bird as being of the same species. On his return to the country, he again met with and shot the bird, which proved to be A. Alcyon. It is now in the collection of Mr. Warren; the other was purchased for the museum of Trinity College, Dublin. This kingfisher, said to be the only species inhabiting North America, is migratory there, and like other birds which have visited Ireland and Great Britain from that continent, has appeared about the period of migration. As an American bird, it is fully treated of by Wilson,Footnote 1 Audubon,Footnote 2 and Richardson Footnote 3. The last author states, that in summer 'it frequents all the large rivers in the fur countries up to the 67th degree of latitude/ It retires to winter in the Southern States, and the West India islands (Wilson and Richardson). Audubon remarks, that 'it is extremely hardy, and those individuals winch migrate northward to breed, seldom return towards our Southern States, where they spend the winter, until absolutely forced to do so by the great severity of the weather/ vol. v.p. 548. Tins is, I believe, the first notice of the species being met with on the eastern side of the Atlantic."

 * Footnote 1 Sir W. Jardine's edit., vol. i. p. 348.
 * Footnote 2 Orn. Biog. vols. i. and v.
 * Footnote 3 Fauna Bor. Amer. p. 339.


text:
The Natural History of Ireland/Volume 1/The Kite

THE KITE.

Milvus regalis, Briss. Falco milvus, Linn.

Is known only as a very rare visitant.

The name of " Kite " appears commonly in the catalogues of birds given in the Statistical Surveys of the Irish counties, and elsewhere; but, as the larger species of the Falconida are in some places called Kite and Glead, as well as Goshawk or Goose- hawk, there can be no doubt that the buzzard, or some common species, was generally meant. The mere fact of rewards having been offered in the Irish Statutes Footnote 1 for the destruction of the " kite," as one of the birds of prey, does not prove anything with respect to the veritable species. Smith, in his History of Cork, completed in 1749, could hardly be mistaken, as he does not content himself with stating that " the kite is distinguished from all other birds of prey by its forked tail," but adds, " that it remains with us all the year." He remarks, however, what we should hardly have expected, that " these birds are so common as to need no particular description." But when the country was more richly wooded, and less populous than at present, it was much better circumstanced for the kite. With the exception of its being stated to have been seen by the Eev. Joseph Stopford, near Blarney, and at Ballincollig Castle, in 1827,Footnote 2 it is now unknown, not only in the county of Cork, but in the whole south of Ireland.

A native bird, either in a wild state, or preserved in a collection, has not come either under my own cognizance, or that of any of my ornithological correspondents; but I have no doubt of the species having been seen in the following instances, as communicated to the Annals of Natural History, in April, 1838. Mr. Adams, the intelligent gamekeeper at Shane's Castle (the seat of Earl O'Neil, on the borders of Lough Neagh), informed me, that " in cold weather," about eight years before that period, he had seen a kite on two or three occasions, hovering over Glenarm Park (Antrim) ; and that in March, 1835, his attention was called to a strange bird, which appeared for three successive days in Shane's Castle park, that proved to be of this species. In both instances, the forked tail served for specific distinction : — neither bird was obtained. My informant knew thespecies well, from having taken it frequently in Northamptonshire: he described it accurately to me. I had before heard from an old gamekeeper, who had hived for many years at Shane's Castle, of a few kites " with tails forked like swallows" having been killed there My friend, William Ogilby, Esq., in one instance, many years ago, saw this species in the county of Londonderry.

Mr. Richard Langtry, when at Loch Awe in Argyleshire, early in the summer of 1833, procured from the nest two young kites, which proved a highly interesting addition to his aviary. They at once became very tame and familiar, and were so gentle in dis- position as to be most engaging. Every morning they had their liberty, and never flew far away, but soaring to a great height in the air, "in still repeated circles," displayed their peculiar and graceful flight. To either lure or " fist " they always returned when called. Mice were preferred by them to birds or any other food. When these kites were on wing, rats let ofP from the cage-trap were expertly caught by them. At the shooting- quarters of Aberarder, in Inverness-shire, a locality apparently well suited to the kite, only one bird was seen by the last-named gentleman during the three autumnal months of 1838 and 1839.

I have met with this most interesting bird amid fine scenery in the west of Scotland ; — in the deer-park at Inverary, and towards the head of the beautiful valley of Glenapp, Ayrshire. In the summer of 1826 I observed it in Switzerland and Italy; and in the celebrated Black Forest of Germany, it was particularly common, admitting there of a close approach without exhibiting any fear.

 * Footnote 1 11th Anne, ch 7 and 17 ; Geo. II. ch. 10.

 * Footnote 2 Communicated by that gentleman to Dr. Harvey of Cork.


text:
The Natural History of Ireland/Volume 1/The Scops-eared Owl

THE SCOPS-EARED OWL.

Scops Aldrovandi, Ray. Strix scops, Linn.

Has been obtained at least twice in Ireland.

The following notice of its first occurrence was communicated by me to the Zoological Society of London, in 1837, and appeared in the Proceedings of that year, p. 54 : — I have been informed by Robert Ball, Esq., of Dublin, that a scops-eared owl was shot in the month of July, a few years ago, by the gamekeeper at Loughcrew, county of Meath, the seat of J. W. L. Naper, Esq., in whose possession it now is. The specimen was kindly sent to Dublin for the examination of Mr. Ball, and proved similar to a Strix Scops in his collection. Mr. Joseph Poole, of Killiane, Wexford, wrote to me on the 19th of April, 1847, that a scops-eared owl, which had come under his notice, was killed a few days before that date, near Kilmore, in the south of the county.

In the month of August, 1826, I met with a bird of this species, perched in what had been a window, among the ruins of Otricoli, near Rome. It admitted of a close approach, and looked most contentedly at home. When proceeding from Malta to the Morea, in H.M.S. Beacon, on the 25th of April, 1841, and 135 miles eastward of Etna, and less than half that distance from Calabria (the nearest land), a scops-eared owl, on its northward flight, came on board. It was struck down and captured, just as it had clutched a lesser whitethroat (Sylvia curruca).

The little Owl (Strix passerina, Temm.), which has occasionally been obtained in England, cannot yet be included with certainty in the Irish catalogue ; — nor can it in that of Scotland. On the 22nd of April, 1841, one of these owls flew on board H.M.S. Beacon, when forty miles east of Malta, and remained for a short time. Others were seen during the next few days, as we sailed towards the Morea. Early in June one was shot at Paros ; and I saw another near Naussa.


text:
Page:Weird Tales volume 30 number 04.djvu/45

Rh and the more so to me because of what I knew of the spot. Refusing to flee, I watched it fade—and as I watched I felt that it was in turn watching me greedily with eyes more imaginable than visible. When I told my uncle about it he was greatly aroused; and after a tense hour of reflection, arrived at a definite and drastic decision. Weighing in his mind the importance of the matter, and the significance of our relation to it, he insisted that we both test—and if possible destroy—the horror of the house by a joint night or nights of aggressive vigil in that musty and fungus-cursed cellar.

4

, June 25, 1919, after a proper notification of Carrington Harris which did not include surmises as to what we expected to find, my uncle and I conveyed to the shunned house two camp chairs and a folding camp cot, together with some scientific mechanism of greater weight and intricacy. These we placed in the cellar during the day, screening the windows with paper and planning to return in the evening for our first vigil. We had locked the door from the cellar to the ground floor; and having a key to the outside cellar door, were prepared to leave our expensive and delicate apparatus—which we had obtained secretly and at great cost—as many days as our vigils might be protracted. It was our design to sit up together till very late, and then watch singly till dawn in two-hour stretches, myself first and then my companion; the inactive member resting on the cot.

The natural leadership with which my uncle procured the instruments from the laboratories of Brown University and the Cranston Street Armory, and instinctively assumed direction of our venture, was a marvelous commentary on the potential vitality and resilience of a man of eighty-one. Elihu Whipple had lived according to the hygienic laws he had preached as a physician, and but for what happened later would be here in full vigor today. Only two persons suspected what did happen—Carrington Harris and myself, I had to tell Harris because he owned the house and deserved to know what had gone out of it. Then too, we had spoken to him in advance of our quest; and I felt after my uncles going that he would understand and assist me in some vitally necessary public explanations. He turned very pale, but agreed to help me, and decided that it would now be safe to rent the house.

To declare that we were not nervous on that rainy night of watching would be an exaggeration both gross and ridiculous. We were not, as I have said, in any sense childishly superstitious, but scientific study and reflection had taught us that the known universe of three dimensions embraces the merest fraction of the whole cosmos of substance and energy. In this case an overwhelming preponderance of evidence from numerous authentic sources pointed to the tenacious existence" of certain forces of great power and, so far as the human point of view is concerned, exceptional malignancy. To say that we actually believed in vampires or werewolves would be a carelessly inclusive statement. Rather must it be said that we were not prepared to deny the possibility of certain unfamiliar and unclassified modifications of vital force and attenuated matter; existing very infrequently in three-dimensional space because of its more intimate connection with other spatial units, yet close enough to the boundary of our own to furnish us occasional manifestations which we, for lack of a proper vantage-point, may never hope to understand.

In short, it seemed to my uncle and


text:
Page:Weird Tales volume 30 number 04.djvu/46

430 me that an incontrovertible array of facts pointed to some lingering influence in the shunned house; traceable to one or another of the ill-favored French settlers of two centuries before, and still operative through rare and unknown laws of atomic and electronic motion. That the family of Roulet had possessed an abnormal affinity for outer circles of entity—dark spheres which for normal folk hold only repulsion and terror—their recorded history seemed to prove. Had not, then, the riots of those bygone seventeen-thirties set moving certain kinetic patterns in the morbid brain of one or more of them— notably the sinister Paul Roulet—which obscurely survived the bodies murdered and buried by the mob, and continued to function in some multiple-dimensioned space along the original lines of force determined by a frantic hatred of the encroaching community?

Such a thing was surely not a physical or biochemical impossibility in the light of a newer science which includes the theories of relativity and intra-atomic action. One might easily imagine an alien nucleus of substance or energy, formless or otherwise, kept alive by imperceptible or immaterial subtractions from the life-force or bodily tissue and fluids of other and more palpably living things into which it penetrates and with whose fabric it sometimes completely merges itself. It might be actively hostile, or it might be dictated merely by blind motives of self-preservation. In any case such a monster must of necessity be in our scheme of things an anomaly and an intruder, whose extirpation forms a primary duty with every man not an enemy to the world's life, health, and sanity.

What baffled us was our utter ignorance of the aspect in which we might encounter the thing. No sane person had ever seen it, and few had ever felt it definitely. It might be pure energy—a form ethereal and outside the realm of substance—or it might be partly material; some unknown and equivocal mass of plasticity, capable of changing at will to nebulous approximations of the solid, liquid, gaseous, or tenuously unparticled states. The anthropomorphic patch of mold on the floor, the form of the yellowish vapor, and the curvature of the tree-roots in some of the old tales, all argued at least a remote and reminiscent connection with the human shape; but how representative or permanent that similarity might be, none could say with any kind of certainty.

devised two weapons to fight it; a large and specially fitted Crookes tube operated by powerful storage batteries and provided with peculiar screens and reflectors, in case it proved intangible and opposable only by vigorously destructive ether radiations, and a pair of military flame-throwers of the sort used in the World War, in case it proved partly material and susceptible of mechanical destruction—for like the superstitious Exeter rustics, we were prepared to burn the thing's heart out if heart existed to burn. All this aggressive mechanism we set in the cellar in positions carefully arranged with reference to the cot and chairs, and to the spot before the fireplace where the mold had taken strange shapes. That suggestive patch, by the way, was only faintly visible when we placed our furniture and instruments, and when we returned that evening for the actual vigil. For a moment I half doubted that I had ever seen it in the more definitely limned form—but then I thought of the legends.

Our cellar vigil began at ten p. m., daylight saving time, and as it continued we found no promise of pertinent developments. A weak, filtered glow from the rain-harassed street-lamps outside, and a


text:
The Natural History of Ireland/Volume 1/The Two-banded Crossbill

THE TWO-BANDED CROSSBILL. European White-winged Crossbill.

Loxia bifasciata, Nilsson.

Has once been obtained.

The first notice of the occurrence of this species in the British islands, is that of Templeton, who communicated to the Linnean Society of London a note of one having been " shot at Grenville, near Belfast, January the 11th, 1802 An extract at p. 276, in- forms us, that the common crossbill was particularly numerous in the southern half of Ireland that season. M. Le Baron De Selys Longchamps, in his excellent " Faune Belge," is of opinion, that the bird called L. leucoptera, in works on British Ornithology, is instead the L. bifasciata, which has been until lately confounded with it: he describes the differences between them (p. 77), and figures the heads and bills of the two species. The latter has been obtained during winter, in Sweden, Germany, and Belgium : the former is a North- American species, which has been killed in England within the last few years . Footnote 1 As Mr. Templeton made a coloured drawing of the specimen, I was desirous that this should be seen by M. De Selys, on his visit to Belfast in the autumn of 1844, but unfortunately it had been taken by Mr. Robert Templeton, along with many other delineations and papers of his father's to Ceylon. The drawing has, however, by the kind attention of my friend just named, been since sent to me from that island, and proves the Irish specimen to have been the L. bifasciata, as described and figured by M. De Selys : it represents the bird of a greenish-olive on the head and back, with dark-brownish markings ; rump yellow ; tail-feathers blackish, bordered with yellow ; entire under plumage yellow, with dark streaks ; two conspicuous white bands across the wings, and the wing-feathers generally (but not all) tipped with white. The form of the bill is identically that of L. bifasciata.

But few individuals of the white-winged crossbill have been obtained in England or Scotland.

Footnote 1 Noticed by Yarrell in the Zoological Proceedings, since the 2nd edit, of his Brit. Birds was published in 1845.


text:
The Natural History of Ireland/Volume 1/The Gold-vented Thrush

THE GOLD-VENTED THRUSH.

Turdus aurigaster, Vieillot.

chrysorhaus, Temm.

Hamatornis, „ Swains.

Has once been killed in Ireland.

By the kindness of Dr. Burkitt of Waterford, who possesses a collection of native birds, (or species killed in Ireland,) I exhibited an individual of this African thrush to the Natural History section of the British Association, held at Cork in 1843. It was purchased by that gentleman from a country -lad who brought it into Waterford in January, 1838, with a number of blackbirds (Turdus merula) and snipes, and who believed it to be a hen blackbird : he shot it at Mount Beresford, three miles and a half from Waterford. There can therefore be no doubt of the specimen having been killed in this country. It is the only individual known to have occurred in Europe. Le Vaillant described the species in his Birds of Africa, vol. iii. p. 46. pi. 107 (Paris 1802), under the name of Le Cudor, stating that it was dis- covered on the banks of the Groot-vis, a river of the Caffre country : little more is yet known respecting it. A. figure, taken from the specimen here noticed, has appeared in the 2nd edition of Yarrells British Birds, and in the Supplementary part to the 1st edition of the same work.

Mr. R. Ball of Dublin informed me in October, 1845, that three birds of a very nearly allied species, brought from Palestine — and called Palestine Nightingales — had been obtained for the aviary of the Zoological Garden, Phoenix Park. They were more of a slate-colour than the species under consideration.


text: User:Tpt/Books/The Original Fables of La Fontaine


text:
User talk:Ake.vastermark

— billinghurst  sDrewth  14:12, 25 June 2012 (UTC)

Uploaded files
Hi. You have uploaded files to English Wikisource without the addition of information relating to copyright. Also, we would normally upload such files to Commons if at all possible, so would you please be able to identify which files we cannot move, and the remainder will be moved over. — billinghurst  sDrewth  14:10, 26 June 2012 (UTC)
 * Ake, this looks like a self-authored work. Has it been published elsewhere?  I am concerned that the work does not fit within the framework as explained at What Wikisource includes.  Would you please explain how the added work fits within these criteria. Thanks. — billinghurst  sDrewth  14:40, 26 June 2012 (UTC)
 * Re copyright, it would be through one of the tags as appropriate at Help:Copyright tags — billinghurst  sDrewth  14:42, 26 June 2012 (UTC)
 * Removed the files. Thanks for the email. — billinghurst  sDrewth  09:03, 28 June 2012 (UTC)
 * I have been through the article and wikified it some more. Of the TIF files, if you know which of the pages had illustrations, then I am willing to pull the relevant files down, and extract the images. As the page at the link that you sent does not have copyright detail, I am going to need to request that you identify yourself as the author of the article using your university address to our OTRS queue.  Can I ask that you have a look at the process at Commons:OTRS and follow it.  The only differences are to note that the article is hosted at English Wikisource and give the relevant url. — billinghurst  sDrewth  11:28, 28 June 2012 (UTC)

title: User talk:Ake.vastermark


text:
User talk:Sriharid

— billinghurst  sDrewth  14:16, 25 June 2012 (UTC)

title: User talk:Sriharid


text:
User talk:Narendrapdange

— billinghurst  sDrewth  14:17, 25 June 2012 (UTC)

title: User talk:Narendrapdange


text: Darwinism (Wallace)/Chapter IX

title: Darwinism (Wallace)/Chapter IX


text: Darwinism (Wallace)/Chapter X

title: Darwinism (Wallace)/Chapter X


text: Darwinism (Wallace)/Chapter XI

title: Darwinism (Wallace)/Chapter XI


text:
The Natural History of Ireland/Volume 1/White’s Thrush

WHITE'S THRUSH.

Turdus Whitei, Eyton.

Has once occurred in Ireland,

As noticed by Mr. G. J. Allman (now Professor of Botany in Trinity College, Dublin,) in the 11th vol. of the Annals of Natural History, p. 78. The communication is dated Dec, 15th, 1842, and states that the writer is in possession of a specimen of this very rare bird, obtained about ten days previously in the neighbourhood of Bandon, county of Cork. It is said in the Pauna of Cork, that the gentleman at whose place the bird was obtained, saw what he believed to be another of the same species there ; but when, is not mentioned.

Two specimens, at most, of T. Whitei have been obtained in Great Britain, and both in Hampshire. The one which has served for the descriptions and figures of the species was shot by Lord Malmesbury in January, 1828. The Irish specimen is similar to it. The following notes upon this bird were made in Dublin in September, 1845, when a comparison was also drawn up between it and a thrush from Nepal, so far as the imperfect specimens would admit : — the Irish bird wants the head and neck j the Nepal one, the legs. The latter specimen was presented by Mr. Hodgson to the museum of Trinity College, Dublin, under the name of Oreocincla Whitei, and noted as a duplicate of one (and numbered 194), which he had presented to the British Museum collection.

[Gives wing feather measurements for Irish specimen and Nepal specimen Rmaking Fourth quill This trivial difference is exceeded by one half in the other wing of the same specimen. In the one wing, the third and fourth quills are of equal length ; in the other, the fourth exceeds the third by one-twelfth of an inch. ] see

The tail of the Irish bird in length and size generally, exceeds that of the Nepal one, as much proportionally as the wing. In colouring and marking the two birds are similar, — agreeing with the descriptions and figures of Eyton and Yarrell, — with the unimportant difference of the Irish one being the deeper in tint, owing, it may be presumed, either to its being killed sooner after moult, or being less exposed to the sun and weather than the Nepal bird. The mere disagreement in size between them is not, I consider, of any specific consequence -, but the discrepancy in the relative length of the quill feathers to each other may be so considered, should it prove to be a permanent character.


text:
Page:Darwinism by Alfred Wallace 1889.djvu/360

theory which we may now take as established—that all the existing forms of life have been derived from other forms by a natural process of descent with modification, and that this same process has been in action during past geological time—should enable us to give a rational account not only of the peculiarities of form and structure presented by animals and plants, but also of their grouping together in certain areas, and their general distribution over the earth's surface.

In the absence of any exact knowledge of the facts of distribution, a student of the theory of evolution might naturally anticipate that all groups of allied organisms would be found in the same region, and that, as he travelled farther and farther from any given centre, the forms of life would differ more and more from those which prevailed at the starting-point, till, in the remotest regions to which he could penetrate, he would find an entirely new assemblage of animals and plants, altogether unlike those with which he was


text:
Page:Darwinism by Alfred Wallace 1889.djvu/361

 familiar. He would also anticipate that diversities of climate would always be associated with a corresponding diversity in the forms of life.

Now these anticipations are to a considerable extent justified. Remoteness on the earth's surface is usually an indication of diversity in the fauna and flora, while strongly contrasted climates are always accompanied by a considerable contrast in the forms of life. But this correspondence is by no means exact or proportionate, and the converse propositions are often quite untrue. Countries which are near to each other often differ radically in their animal and vegetable productions; while similarity of climate, together with moderate geographical proximity, are often accompanied by marked diversities in the prevailing forms of life. Again, while many groups of animals—genera, families, and sometimes even orders—are confined to limited regions, most of the families, many genera, and even some species are found in every part of the earth. An enumeration of a few of these anomalies will better illustrate the nature of the problem we have to solve.

As examples of extreme diversity, notwithstanding geographical proximity, we may adduce Madagascar and Africa, whose animal and vegetable productions are far less alike than are those of Great Britain and Japan at the remotest extremities of the great northern continent; while an equal, or perhaps even a still greater, diversity exists between Australia and New Zealand. On the other hand, Northern Africa and South Europe, though separated by the Mediterranean Sea, have faunas and floras which do not differ from each other more than do the various countries of Europe. As a proof that similarity of climate and general adaptability have had but a small part in determining the forms of life in each country, we have the fact of the enormous increase of rabbits and pigs in Australia and New Zealand, of horses and cattle in South America, and of the common sparrow in North America, though in none of these cases are the animals natives of the countries in which they thrive so well. And lastly, in illustration of the fact that allied forms are not always found in adjacent regions, we have the tapirs, which are found only on opposite sides of the globe, in tropical America and the Malayan Islands; the camels of


text:
Page:Darwinism by Alfred Wallace 1889.djvu/362

 the Asiatic deserts, whose nearest allies are the llamas and alpacas of the Andes; and the marsupials, only found in Australia and on the opposite side of the globe, in America. Yet, again, although mammalia may be said to be universally distributed over the globe, being found abundantly on all the continents and on a great many of the larger islands, yet they are entirely wanting in New Zealand, and in a considerable number of other islands which are, nevertheless, perfectly able to support them when introduced.

Now most of these difficulties can be solved by means of well-known geographical and geological facts. When the productions of remote countries resemble each other, there is almost always continuity of land with similarity of climate between them. When adjacent countries differ greatly in their productions, we find them separated by a sea or strait whose great depth is an indication of its antiquity or permanence. When a group of animals inhabits two countries or regions separated by wide oceans, it is found that in past geological times the same group was much more widely distributed, and may have reached the countries it inhabits from an intermediate region in which it is now extinct. We know, also, that countries now united by land were divided by arms of the sea at a not very remote epoch; while there is good reason to believe that others now entirely isolated by a broad expanse of sea were formerly united and formed a single land area. There is also another important factor to be taken account of in considering how animals and plants have acquired their present peculiarities of distribution,—changes of climate. We know that quite recently a glacial epoch extended over much of what are now the temperate regions of the northern hemisphere, and that consequently the organisms which inhabit those parts must be, comparatively speaking, recent immigrants from more southern lands. But it is a yet more important fact that, down to middle Tertiary times at all events, an equable temperate climate, with a luxuriant vegetation, extended to far within the arctic circle, over what are now barren wastes, covered for ten months of the year with snow and ice. The arctic zone has, therefore, been in past times capable of supporting almost all the forms of life of our temperate regions; and we


text:
Page:Darwinism by Alfred Wallace 1889.djvu/363

 must take account of this condition of things whenever we have to speculate on the possible migrations of organisms between the old and new continents.

When we endeavour to explain in detail the facts of the existing distribution of organic beings, we are confronted by several preliminary questions, upon the solution of which will depend our treatment of the phenomena presented to us. Upon the theory of descent which we have adopted, all the different species of a genus, as well as all the genera which compose a family or higher group, have descended from some common ancestor, and must therefore, at some remote epoch, have occupied the same area, from which their descendants have spread to the regions they now inhabit. In the numerous cases in which the same group now occupies countries separated by oceans or seas, by lofty mountain-chains, by wide deserts, or by inhospitable climates, we have to consider how the migration which must certainly have taken place has been effected. It is possible that during some portion of the time which has elapsed since the origin of the group the interposing barriers have not been in existence; or, on the other hand, the particular organisms we are dealing with may have the power of overpassing the barriers, and thus reaching their present remote dwelling-places. As this is really the fundamental question of distribution on which the solution of all its more difficult problems depends, we have to inquire, in the first place, what is the nature of, and what are the limits to, the changes of the earth's surface, especially during the Tertiary and latter part of the Secondary periods, as it was during those periods that most of the existing types of the higher animals and plants came into existence; and, in the next place, what are the extreme limits of the powers of dispersal possessed by the chief groups of animals and plants. We will first consider the question of barriers, more especially those formed by seas and oceans.

It was formerly a very general belief, even amongst geologists, that the great features of the earth's surface, no less than the smaller ones, were subject to continual mutations,


text:
Page:Darwinism by Alfred Wallace 1889.djvu/364

 and that during the course of known geological time the continents and great oceans had again and again changed places with each other. Sir Charles Lyell, in the last edition of his Principles of Geology (1872), said: "Continents, therefore, although permanent for whole geological epochs, shift their positions entirely in the course of ages;" and this may be said to have been the orthodox opinion down to the very recent period when, by means of deep-sea soundings, the nature of the ocean bottom was made known. The first person to throw doubt on this view appears to have been the veteran American geologist, Professor Dana. In 1849, in the Report of Wilke's Exploring Expedition, he adduced the argument against a former continent in the Pacific during the Tertiary period, from the absence of all native quadrupeds. In 1856, in articles in the American Journal, he discussed the development of the American continent, and argued for its general permanence; and in his Manual of Geology in 1863 and later editions, the same views were more fully enforced and were latterly applied to all continents. Darwin, in his Journal of Researches, published in 1845, called attention to the fact that all the small islands far from land in the Pacific, Indian, and Atlantic Oceans are either of coralline or volcanic formation. He excepted, however, the Seychelles and St. Paul's rocks; but the former have since been shown to be no exception, as they consist entirely of coral rock; and although Darwin himself spent a few hours on St. Paul's rocks on his outward voyage in the Beagle, and believed he had found some portions of them to be of a "cherty," and others of a "felspathic" nature, this also has been shown to be erroneous, and the careful examination of the rocks by the Abbé Renard clearly proves them to be wholly of volcanic origin. We have, therefore, at the present time, absolutely no exception whatever to the remarkable fact that all the oceanic islands of the globe are either of volcanic or coral formation; and there is, further, good reason to believe that those of the latter class in every case rest upon a volcanic foundation.

In his Origin of Species, Darwin further showed that no true oceanic island had any native mammals or batrachia


text:
Page:Darwinism by Alfred Wallace 1889.djvu/365

 when first discovered, this fact constituting the test of the class to which an island belongs; whence he argued that none of them had ever been connected with continents, but all had originated in mid-ocean. These considerations alone render it almost certain that the areas now occupied by the great oceans have never, during known geological time, been occupied by continents, since it is in the highest degree improbable that every fragment of those continents should have completely disappeared, and have been replaced by volcanic islands rising out of profound oceanic abysses; but recent research into the depth of the oceans and the nature of the deposits now forming on their floors, adds greatly to the evidence in this direction, and renders it almost a certainty that they represent very ancient if not primaeval features of the earth's surface. A very brief outline of the nature of this evidence will be now given.

The researches of the Challenger expedition into the nature of the sea-bottom show, that the whole of the land debris brought down by rivers to the ocean (with the exception of pumice and other floating matter), is deposited comparatively near to the shores, and that the fineness of the material is an indication of the distance to which it has been carried. Everything in the nature of gravel and sand is laid down within a very few miles of land, only the finer muddy sediments being carried out for 20 or 50 miles, and the very finest of all, under the most favourable conditions, rarely extending beyond 150, or at the utmost, 300 miles from land into the deep ocean. Beyond these distances, and covering the entire ocean floor, are various oozes formed wholly from the debris of marine organisms; while intermingled with these are found various volcanic products which have been either carried through the air or floated on the surface, and a small but perfectly recognisable quantity of meteoric matter. Ice-borne rocks are also found abundantly scattered over the ocean bottom within a definite distance of the arctic and antarctic circles, clearly marking out the limit of floating icebergs in recent geological times.


text:
Page:Darwinism by Alfred Wallace 1889.djvu/366

 Now the whole series of marine stratified rocks, from the earliest Palaeozoic to the most recent Tertiary beds, consist of materials closely corresponding to the land debris now being deposited within a narrow belt round the shores of all continents; while no rocks have been found which can be identified with the various oozes now forming in the deep abysses of the ocean. It follows, therefore, that all the geological formations have been formed in comparatively shallow water, and always adjacent to the continental land of the period. The great thickness of some of the formations is no indication of a deep sea, but only of slow subsidence during the time that the deposition was in progress. This view is now adopted by many of the most experienced geologists, especially by Dr. Archibald Geikie, Director of the Geological Survey of Great Britain, who, in his lecture on "Geographical Evolution," says: "From all this evidence we may legitimately conclude that the present land of the globe, though consisting in great measure of marine formations, has never lain under the deep sea; but that its site must always have been near land. Even its thick marine limestones are the deposits of comparatively shallow water."

But besides these geological and physical considerations, there is a mechanical difficulty in the way of repeated change of position of oceans and continents which has not yet received the attention it deserves. According to the recent careful estimate by Mr. John Murray, the land area of the globe is to the water area as ·28 to ·72. The mean height of the land above sea-level is 2250 feet, while the mean depth of the ocean is 14,640 feet. Hence the bulk of dry land is 23,450,000 cubic miles, and that of the waters of the ocean 323,800,000 cubic miles; and it follows that if the whole of the solid matter of the earth's surface were reduced to one level, it would be everywhere covered by an ocean about two miles deep. The accompanying diagram will serve to render these figures more intelligible. The length of the sections of land and ocean are in the proportion of their respective areas, while the mean height of the land and the mean depth of the ocean are exhibited on a greatly increased


text:
Page:Darwinism by Alfred Wallace 1889.djvu/367

 vertical scale. If we considered the continents and their adjacent oceans separately they would differ a little, but not very materially, from this diagram; in some cases the proportion of land to ocean would be a little greater, in others a little less.

Now, if we try to imagine a process of elevation and depression by which the sea and land shall completely change places, we shall be met by insuperable difficulties. We must, in the first place, assume a general equality between elevation and subsidence during any given period, because if the elevation over any extensive continental area were not balanced by some subsidence of approximately equal amount, an unsupported hollow would be left under the earth's crust. Let us now suppose a continental area to sink, and an adjacent oceanic area to rise, it will be seen that the greater part of the land will disappear long before the new land has approached the surface of the ocean. This difficulty will not be removed by supposing a portion of a continent to subside, and the immediately adjacent portion of the ocean on the other side of the continent to rise, because in almost every case we find that within a comparatively short distance from the shores of all existing continents, the ocean floor sinks rapidly to a depth of from 2000 to 3000 fathoms, and maintains a similar depth, generally speaking, over a large portion of the oceanic areas. In order, therefore, that any area of continental extent be upraised from the great oceans, there must be a subsidence of a land area five or six times as great, unless it can be shown that an extensive elevation of the ocean floor up to and far


text:
Page:Our Philadelphia (Pennell, 1914).djvu/217

Rh law. Members of a Protestant church might dispute among themselves to the point of blows, but they never thought of interfering with the members of any other church, except the Catholic, against which they could all cheerfully join. There were times when the Friends, most tolerant of men, were influenced by this general hostility, and I rather think the worst moment in Penn's life was when he was forced to protest against the scandal of the Mass in his town of Brotherly Love.

The marvel is that Catholics ventured out of their hiding-places as soon as they did. They had emerged so successfully by Revolutionary times that the stranger in Philadelphia could find his way to "the Romish chapel" and enjoy the luxury of knowing that he was not as these poor wretches who fingered their beads and chanted Latin not a word of which they understood. The Jesuits have the wisdom of their reputation. When they built their church the Colonies had for some years been the United States, and hatred was less outspoken, and persecution was more intermittent, but they believed discretion to be the better part of valour and the truest security in not challenging attack. That is why they built St. Joseph's in Willing's Alley where the visitor with a dramatic sense must be as thrilled by it as by the secret chapels and underground passages in old Elizabethan mansions and Scott's novels. Philadelphia gave the Jesuits a proof of their wisdom when, within a quarter of a century, Young


text:
Page:Darwinism by Alfred Wallace 1889.djvu/368

 above the surface could occur without an equivalent depression elsewhere. The fact that the waters of the ocean are sufficient to cover the whole globe to a depth of two miles, is alone sufficient to indicate that the great ocean basins are permanent features of the earth's surface, since any process of alternation of these with the land areas would have been almost certain to result again and again in the total disappearance of large portions, if not of all, of the dry land of the globe. But the continuity of terrestrial life since the Devonian and Carboniferous periods, and the existence of very similar forms in the corresponding deposits of every continent—as well as the occurrence of sedimentary rocks, indicating the proximity of land at the time of their deposit, over a large portion of the surface of all the continents, and in every geological period—assure us that no such disappearance has ever occurred.

When we speak of the permanence of oceanic and continental areas as one of the established facts of modern research, we do not mean that existing continents and oceans have always maintained the exact areas and outlines that they now present, but merely, that while all of them have been undergoing changes in outline and extent from age to age, they have yet maintained substantially the same positions, and have never actually changed places with each other. There are, moreover, certain physical and biological facts which enable us to mark out these areas with some confidence.

We have seen that there are a large number of islands which may be classed as oceanic, because they have never formed parts of continents, but have originated in mid-ocean, and have derived their forms of life by migration across the sea. Their peculiarities are seen to be very marked in comparison with those islands which there is good reason to believe are really fragments of more extensive land areas, and are hence termed "continental." These continental islands consist in every case of a variety of stratified rocks of various ages, thus corresponding closely with the usual structure of continents; although many of the islands are small like Jersey or the Shetland Islands, or far from continental land like the Falkland Islands or New Zealand. They all


text:
Page:Darwinism by Alfred Wallace 1889.djvu/369

 contain indigenous mammalia or batrachia, and generally a much greater variety of birds, reptiles, insects, and plants, than do the oceanic islands. From these various characteristics we conclude that they have all once formed parts of continents, or at all events of much larger land areas, and have become isolated, either by subsidence of the intervening land or by the effects of long-continued marine denudation.

Now, if we trace the thousand-fathom line around all our existing continents we find that, with only two exceptions, every island which can be classed as "continental" falls within this line, while all that lie beyond it have the undoubted characteristics of "oceanic" islands. We, therefore, conclude that the thousand-fathom line marks out, approximately, the "continental area,"—that is, the limits within which continental development and change throughout known geological time have gone on. There may, of course, have been some extensions of land beyond this limit, while some areas within it may always have been ocean; but so far as we have any direct evidence, this line may be taken to mark out, approximately, the most probable boundary between the "continental area," which has always consisted of land and shallow sea in varying proportions, and the great oceanic basins, within the limits of which volcanic activity has been building up numerous islands, but whose profound depths have apparently undergone little change.

The two exceptions just referred to are Madagascar and New Zealand, and all the evidence goes to show that in these cases the land connection with the nearest continental area was very remote in time. The extraordinary isolation of the productions of Madagascar—almost all the most characteristic forms of mammalia, birds, and reptiles of Africa being absent from it—renders it certain that it must have been separated from that continent very early in the Tertiary, if not as far back as the latter part of the Secondary period; and this extreme antiquity is indicated by a depth of considerably more than a thousand fathoms in the Mozambique Channel, though this deep portion is less than a hundred miles wide between the Comoro Islands and the


text:
Page:Darwinism by Alfred Wallace 1889.djvu/370

. Madagascar is the only island on the globe with a fairly rich mammalian fauna which is separated from a continent by a depth greater than a thousand fathoms; and no other island presents so many peculiarities in these animals, or has preserved so many lowly organised and archaic forms. The exceptional character of its productions agrees exactly with its exceptional isolation by means of a very deep arm of the sea.

New Zealand possesses no known mammals and only a single species of batrachian; but its geological structure is perfectly continental. There is also much evidence that it does possess one mammal, although no specimens have been yet obtained. Its reptiles and birds are highly peculiar and more numerous than in any truly oceanic island. Now the sea which directly separates New Zealand from Australia is more than 2000 fathoms deep, but in a north-west direction there is an extensive bank under 1000 fathoms, extending to and including Lord Howe's Island, while north of this are other banks of the same depth, approaching towards a submarine extension of Queensland on the one hand, and New Caledonia on the other, and altogether suggestive of a land union with Australia at some very remote period. Now the peculiar relations of the New Zealand fauna and flora with those of Australia and of the tropical Pacific Islands to the northward indicate such a connection, probably during the Cretaceous period; and here, again, we have the exceptional depth of the dividing sea and the form of the ocean bottom according well with the altogether exceptional isolation of New Zealand, an isolation which has been held by some naturalists to be great enough to justify its claim to be one of the primary Zoological Regions.

If now we accept the annexed map as showing us approximately how far beyond their present limits our continents may


text: Page:Darwinism by Alfred Wallace 1889.djvu/371


text:
Page:Our Philadelphia (Pennell, 1914).djvu/218

198 America, in a playful moment, burnt down as much as it could of St. Michael's and St. Augustine's; churches which had been built bravely and hopefully in open places. Young America believed in a healthy reminder to Catholics, that, if they had not been disturbed for some time, it was not because they did not deserve to be.

Philadelphia had got beyond the exciting stage of intolerance before I was born. There were no delicious tremors to be had when I heard Mass at St. Joseph's or went to Vespers at St. Mary's. There was no ear alert for a warning of the approach of the enemy, no eye strained for the first wisp of smoke or burst of flame. With churches and convents everywhere—convents intruding even upon Walnut Street and Rittenhouse Square—with a big Cathedral in town and a big Seminary at Villanova, Catholics were in a fair way to forget it had ever been as dangerous for them as for the early Christians to venture from their catacombs. Their religion had become a tame affair, holding out no prospect of the martyr's crown. Only the social prejudice survived, but it was the more bitter to fight because, whether the end was victory or defeat, it appeared so inglorious a struggle to be engaged in.

One good result there was of this social ostracism. I leave myself out of the argument. Religion, I have often heard it said, is a matter of temperament. As this story of my relations to Philadelphia seems to be resolving itself into a general confession, I must at least confess my


text: Page:Darwinism by Alfred Wallace 1889.djvu/372


text:
Page:Darwinism by Alfred Wallace 1889.djvu/373

 have extended during any portion of the Tertiary and Secondary periods, we shall obtain a foundation of inestimable value for our inquiries into those migrations of animals and plants during past ages which have resulted in their present peculiarities of distribution. We see, for instance, that the South American and African continents have always been separated by nearly as wide an ocean as at present, and that whatever similarities there may be in their productions must be due to the similar forms having been derived from a common origin in one of the great northern continents. The radical difference between the higher forms of life of the two continents accords perfectly with their permanent separation. If there had been any direct connection between them during Tertiary times, we should hardly have found the deep-seated differences between the Quadrumana of the two regions—no family even being common to both; nor the peculiar Insectivora of the one continent, and the equally peculiar Edentata of the other. The very numerous families of birds quite peculiar to one or other of these continents, many of which, by their structural isolation and varied development of generic and specific forms, indicate a high antiquity, equally suggest that there has been no near approach to a land connection during the same epoch.

Looking to the two great northern continents, we see indications of a possible connection between them both in the North Atlantic and the North Pacific oceans; and when we remember that from middle Tertiary times backward—so far as we know continuously to the earliest Palaeozoic epoch—a temperate and equable climate, with abundant woody vegetation, prevailed up to and within the arctic circle, we see what facilities may have been afforded for migration from one continent to the other, sometimes between America and Europe, sometimes between America and Asia. Admitting these highly probable connections, no bridging of the Atlantic in more southern latitudes (of which there is not a particle of evidence) will have been necessary to account for all the intermigration that has occurred between the two continents. If, on the other hand, we remember how long must have been the route, and how diverse must always have been the conditions between the more northern and the more southern portions of the American and Euro-Asiatic continents, we shall not be