Studies in the volution of Animals E.Bonavia, M.D. :;..,;• SIP STUDIES IN THE EVOLUTION OF ANIMALS ' The best that you can do is to write the book that it gives you the most pleasure to write, to put as much heart and soul as you have about you into it, and then hope as hard as you can to reach the heart and soul of the great multitude of your fellow-men.' The Man of Letters as a Man of Business, by W. D. HOWELLS, Scribner's Magazine, October 1893. EVOLUTION OF ANIMALS BY E. BON AVI A, M.D. BRIGADE SURGEON I.M.D. AUTHOR OF 'THE CULTIVATED ORANGES AND LEMONS OF INDIA AND CEYLON,' ' PHILOSOPHICAL NOTES ON BOTANICAL SUBJECTS,' 'THE FLORA OF THE ASSYRIAN MONUMENTS AND ITS OUTCOMES ' WITH ONE HUNDRED AND TWENTY-EIGHT IL LUSTRA TIONS ARCHIBALD CONSTABLE AND COMPANY PUBLISHERS TO THE INDIA OFFICE 14 PARLIAMENT STREET, S.W. MDCCCXCV [A U Rights rese rved] Edinburgh : T. and A. CONSTABLE, Printers to Her Majesty CONTENTS PAGE PREFACE, . . . . . . . . . . vii INTRODUCTION, ........ xv PART I. — Spotted and Striped Mammals (Horses excepted), . . i „ II. — Dappled and Striped Horses, and some other Mammals, . 57 „ ill. — Meaning of the Jaguar and Leopard Rosettes, and of the markings of other Mammals, . . . . 99 „ iv. — Further evidence in support of the theory that existing Mam- mals descended from carapaced ancestors, . . 135 „ V. — Researches and discussions to connect, more surely, Armour- plating with Skin-picturing, . . . .153 „ VI. — Probable meaning of some interesting features in Horses and other animals, ...... 165 „ vii. — Is Natural Selection the sole factor in the Coloration of Mammals ?...... 189 „ viii. — Probable cause of the loss of the Calcareous Armour in Mammals, ...... 199 „ ix. — Relationship between the Armadillo, the Rhinoceros, the Horse, the Giraffe, and the Zebu, . . . 213 vi STUDIES IN THE EVOLUTION OF ANIMALS PAGE PART x, — Explanation of the Callosities on the Legs of Equine Animals and others, . . . 229 „ xi. — The One Big Digit of the Horse, . . . . 241 „ XII. — Monstrosities as probable factors in the creation of species, . 273 GENERAL CONCLUSIONS, . . . 325 APPENDICES, . . 331 PREFACE Of what value would the objective facts alone have been, even if they were collected by millions, without a colligating theory which puts sou! into the scattered facts? They would be as soulless as heaps of bricks and mortar are before they are built up into a Cathedral. Theory founded on facls, as it should be, is of the greatest importance in forming a right conception of Nature. Theories cannot flash out in all perfection. They require to be mended, and time is needed for that. PREFACE THE genesis of these studies was the following :— Having completed the Flora of the Assyrian Monuments and its Outcomes, I was looking about for something to take up next as a subject of study. In the furriers' windows I was attracted by the Leopard and Tiger skins, which by degrees became objects of interesting study and speculation. Thinking over the rosettes of the Leopards, and more especially those of the Jaguar, and seeing spotted Horses constantly in the streets of London, some new ideas flashed across my mind regarding the origin of all this spotting and resetting in mammals. Keeping ' my eyes open/ so as to get some insight into the invisible, and making many researches for some tangible facts which would serve as a basis for my speculations, the subjects of the curious callosities on the legs of the Horse, its solitary big digit, its possible close relationship to the pair of digits in the ruminants, and various monstrosities, came under review, as well as several other collateral points, and so, each group, as it became interesting, was worked up into a separate study, followed up by that on the meaning of the rosettes on the Jaguar and allied animals, and of the dapples which are all but universal in Horses x STUDIES IN THE EVOLUTION OF ANIMALS —whether as a completely dappled surface, or as vestiges of an extensively spotted skin. Spotting and striping in mammals, or vestiges of such markings, are to be met with so extensively among these animals, that I came to the conclusion they must have a deeper meaning than may have hitherto been attributed to them by evolutionists. The reader should understand that a book like this is not written as a poem might be written, by sitting down in some suggestive surrounding, gazing into space, and letting the thoughts come rambling after each other, as if by inspiration. Not a few perhaps may think that the author just sat down and wrote it off! Few would consider what interminable searching for authorities was needed ; what hunting for facts and evidence to build upon ; what hunting for suitable skins and animals to be photographed, and for photographs of animals to be used as illustrations, were required. Nowadays, one might as well speak to the wind as produce a book of this sort without numerous illustrations. The value of an illustration is that it appeals to the mind at once, while a string of words used in a description, without an illustration, would only, in most cases, fatigue the reader's mind, and leave little or no impression. Everything must be made as easy as possible for the student and general reader, otherwise he or she will turn to something else. There is too much to distract the attention from making a serious effort to comprehend even a small portion of the work of creation. Moreover, this is the age of maga- zines, which mean a conglomerate, and most people prefer that. The arrangement of notes taken at all sorts of odd times and places ; the digesting and comparing of points, writing out PREFACE xi notions, tearing them up, and re-writing them, and a hundred other troubles, would all have been the most wearisome work had it not been backed by the stimulus and enthusiasm roused by the convic- tion that there was something interesting to be told. If the reader should feel a hundredth part of the interest, in reading these pages, that I felt in writing them, I am sure he ought to be a happy individual. In these pages there may be some things which scientists may have either overlooked as unimportant, or which they may not have cared to tackle, appearing to them as insoluble. I have also attempted to develop particular points in the sub- theories of the more general theory or doctrine of evolution. As Professor Huxley is stated to have declared at Oxford not long ago,1 even if Darwinism were swept away it would leave evolution untouched. The doctrine of * creation by the method of evolution ' has replaced all other doctrines, and it cannot be upset by mortals, for it is based on the every-day experience that a mother pro- creates children, and these other children, and these others, and so forth. No one yet has even attempted to upset that fact of nature. The study of the coloration of mammals is an intricate one ; and in the various parts of this discussion repetitions could hardly be avoided ; but although wearisome to the expert, the general reader, who may not be very conversant with the facts of evolution and natural selection — should he care to study this part of modern philosophy — may derive benefit from these 1 After the Inaugural Address of Lord Salisbury to the British Association, 8th August 1894. xii STUDIES IN THE EVOLUTION OF ANIMALS unavoidable though wearisome repetitions. Moreover, I am not aware that there is any particular sin in a little repetition. The reader after all is not so sacred a thing as not to be subjected on any account to a little tedium. Some little allowance then, I suppose, may be made for the ' personal equation ' of the writer ! I do not know a better method for fixing notions on the reader's convolutions — more especially if he or she is not easily convinced — than by ' hammering ' on the same subject in different ways, in order to make an impression. Few people who may be tempted to open a book do so with the spirit of the student who endeavours to master the meaning and points therein contained. The majority of persons who take up a book want to be amused, distracted, or somehow entertained, and few are the books on evolutionary studies which can satisfy either of these cravings. Inferences cannot be safely drawn from any particular speci- men ; the larger the number of specimens on which an inference is based, the more soundness will it be likely to possess. Where too much detail might seem tedious to the expert, I would note that it is intended for the general reader who may be tempted to dip into these subjects, and who may not have given much attention to such matters. If found tedious, whole pages may be skipped by the expert. I believe that this is the first time that any attempt has been made to study the markings of mammals in detail, with the view of reaching what seems to be the real, or at all events the proximate, cause of their existence. Mr. Tylor and Mr. Poulton, PREFACE xiii Dr. Wallace and Mr. Darwin have studied the coloration of animals ; but, as far as I am aware, no attempt has been hitherto made to account for certain markings which occur, as one might say, in a sort of plan, and in so many different animals. In these pages I have made an attempt to account, not only for their derivation, but also for their genesis, as far as this can be known. I need hardly mention that the figures of Horses were not selected for their beauty of outline, but for their dappling. Most of the outline drawings are reduced in size. My thanks are due to Professor J. M'Fadyean and Mr. P. D. Coghill of the Royal Veterinary College, for helping me with photographs of Horses ; and to Mr. James Poynter of the Horse department of the Great Northern Railway, and Mr. William D. Duff, manager of the London Road Car Company, for their kind permission to photograph some of the horses in the stables of their companies. I have to thank also Messrs. Jeffs and Harris, and Messrs. Back and Co., of Regent Street, for allowing me to have some of the skins in their stores photographed. Finally, my thanks are due to Miss Butcher for numerous out- line drawings of mammals, etc., in the Natural History Museum. Some apology is, I think, due to her for asking her to make drawings of those archaeological exhibitions of Taxidermy. As she remarked, it was difficult to know where their legs ought to be ! The recent specimens in that museum are, however, splendidly got up. E. BONAVIA. INTRODUCTION ' Evolution is the most striking feature of modern scientific thought, hence all that terms itself evolution must be scientific — such seems to be the logic of the average reviewer, and, we regret to say it, of some men of science who ought to know better. The fact is that the word " evolution " has been so terribly abused, first by the biologists, then by pseudo-scientists, and lastly by the public, that it has become a cant term to cover any muddle-headed reasoning, which would utterly fail to justify itself had it condescended to apply the rule of three. A variety of ill-described and ill-appreciated factors of change have all been classed together and entitled the theory of evolution.' Socialism and Natural Selection, by KARL PEARSON, Fortnightly Review, July 1894, p. I. ERRATA. p. 49, Note I., for Vol. II., read Plate II. p. 123, for in Fig. 62 (c), read Fig. 62 (c). p. 132, for ages in the 4th para., read stages. p. 192, for Fig. 73, read 76A. p. 193, for Fig. 73, read 76A. p. 287, for Gelasimus arenatus, read arcuahis. INTRODUCTION ' IT is not enough that a scientific truth should be the possession of a privileged few ; those who value the truth should try to spread it, and make it common intellectual property, and this can only be done when they realise that simplicity of language, and correct style, and a good arrangement, are essential to its propagation.' ' The British Association,' Nature ', i6th August 1894. ANY one who may think of devoting his attention to the study of the philosophy of life, based, not only on the materials he has himself observed and discovered, but also on those worked up by others, is met, at the outset, with a huge mountain of words. ' Words will govern us, if we do not govern them/ said Professor Max Miiller. Any one who tries to get at the bottom of facts, and at the bottom of the inferences resulting from those facts, has to grope his way through this maze of often utterly useless, if not mis- chievous, terminology. The essential truth may be obscured by the novel and difficult-to-be-remembered wording ; so that we often * cannot see the wood for the trees.' By way of introduction to the introduction, let us take a glance at what even leading scientists think of it all. If scientific men complain of the nuisance, what would you say the man in the street would think of it ? M. L. Guinard in his Precis de Teratologie, p. xvi., gives expres- sion to the feeling of distress caused by hasty and reckless additions to modern scientific nomenclature. He says : ' La multiplication des termes aurait fatalement la meme consequence que la multi- b xviii STUDIES IN THE EVOLUTION OF ANIMALS plication des langues ; celui qui songera a jeter les bases d'un edifice taxonomique par trop nouveau aboutira a 1'edification d'une tour de Babel. 'Si j'insiste sur cette particularite, c'est que moi-meme j'ai ete souvent embarrasse par la diversite de noms et des classifications, et parce que actuellement, on voit la tendence dont je parle persister encore dans quelques travaux fort remarquables d'ailleurs.' Then Mr. Stebbing, in his interesting work on the Crustacea, p. 255, referring to Mr. Spence Bates' 'Report on the Challenger Macrural says, * But simplicity seems to be the very last thing considered in Spence Bates' terminology, and though such words as phymacerite, psalistoma, and stylamblys, may help to curtail the length of descriptions, they are only too likely also to curtail the number of those that read them.' And certainly this is one of the mischiefs wrought by unneces- sary coining of new terms to express ideas which might in many cases be conveyed in ordinary wording. Very recently another note of warning has been sounded in Natural Science of October 1893, under the heading of ' Scientific Linguistics ' : ' When a layman asks a naturalist why he invents and employs such a multitude of incomprehensible technical terms, the common reply is that exact ideas necessitate a precise and universally (!) understood nomenclature. We wonder how this explanation would apply to the terms of " Auxology," or " Bioplast- ology," just discussed by Professor A. Hyatt in the Zoologischer Anzeiger (concluded August 28, 1893). We should like to know how much scientific precision there is in the determination of the nepionic, metanepionic, gerontic, paragerontic, etc., stages of any organism, and what grain of solid fact, as compared with mere specu- lation, in the so-called definition of the phylonepionic, phyloneanic, phylogerontic, etc., phases of development in any group of animals. INTRODUCTION xix We may be enslaved by some prejudice, and our patience may have been ruffled in the attempt to decipher some recent writings of American authors on fossil shells ; but we cannot help uttering a protest against the clothing of a tissue of hypothetical fabrications in a garb of a precisely-defined scientific nomenclature.' In a note to p. 1366, Nicholson and Lydekker1 complain of the same trouble. Regarding the genera of Rhinoceroses of the American school, they say : ' From the writers' point of view the multiplication of generic terms, which, as our knowledge advances, must become less and less susceptible of exact definition, tends to drown the science in a sea of names, which form a great burden to the memory, and thus tend to destroy the very object of classification.' Classification is not the end of a science, but the means of facilitating the conception of creation by the method of evolution ; and if the whole conception be obscured under a heap of names, its object will be surely defeated. ' La haute science ' would appear to consist now in the faculty of inventing such names as the following : — ' ids,' ' idants,' ' idio- plasm,' ' somatic idio-plasm,' * morpho-plasm,' * apical-plasm,' as composing the 'sphere' of germ-plasm, and which the late Professor Romanes 2 compared to the nine circles of Dante's Inferno \ I ask again, if scientists are groaning under the grip of this ' demon ' of chaotic modern nomenclature, what should the poor beginner say, who would have to commit to memory such an amount of useless terms before he can understand what the professor is talking about. All this needless multiplication of terms is worrying and distressing to the ' grey matter ' of the brain 1 Manual of Paleontology. 2 Examination of Weismannism^. 118. xx STUDIES IN THE EVOLUTION OF ANIMALS of both professor and student, and to all earnest investigators, who wish to get to the bottom of creation by the method of evolution. As to the general reader, he may probably say : ' Non ragioniam di lor, guarda e passa.' This troublesome multiplicity of useless words has certainly become a formidable difficulty to those who may wish to pursue scientific investigations, and an obstruction to the progress of Science ; for if, before attempting to devote one's time to the study of the * Philosophy of the Sciences/ one has to learn a language as difficult as that of cuneiform inscriptions, it will deter many from embarking in such a pursuit. Is it any wonder that ordinary people do not think that scientific men are either so sensible and unselfish as they may think themselves to be ? The curious part is that tyros may perhaps think that these strange and unpronounceable words are the science, and may startle their friends with the extent of scientific knowledge they have acquired at the schools, colleges, or universities ! Are then the facts of the universe, and the discoveries made by scientific explorers, to remain the possession of the few, by being locked up in a language which only means ' hieroglyphics ' to most ordinary men and women ? It is truly touching to contemplate the helplessness of the human mind in face of the prodigious number of variations it has to deal with in studying organic forms. Mr. Stebbing, in the before-mentioned work, p. 43, says : ' It may here be mentioned that the full number of joints for a malacostracean trunk leg is seven. The afflicted naturalist has for many years had to deal with these seven under the following names, coxa, basis, ischium, merus, carpus, propodus, dactylus, which respectively signify hip, foot, socket of thigh joint, wrist, forefoot, and finger or toe. INTRODUCTION xxi ' Originally the names were longer, all being podites, from coxopodite to dactylopodite ; to the use of these the philosophic French still adhere, though the time-saving Anglo-Saxon has for the most part rejected them ! . . . The more reasonable plan is now to denote them by means of figures from first joint to seventh joint.' As the antennae of the Lobster are homologous with podites, it is a wonder that a hundred names had not been invented to designate their hundred or more distinct joints. Why not have had also a separate name for each hair on a man's head ? ! The followers of Galileo have had their revenge by pointing out the innumerable absurdities of the teachings of the Church ; but the turn of the Church may come, and it may have its revenge ! The mischief of all this is that the mass of mankind, even in the most civilised countries, both men and women, are wholly ignorant of the simplest facts of creation, and all these unnecessary difficulties only increase their reluctance to have anything to do with the wonders of nature. The craving for coining new words at every turn has already landed us in a sort of mental chaos, and earnest thinkers see that no advantage can come from this bewildering multiplicity of terms towards a simplification of science. It only burdens the memory of those who may be courageous enough to follow scientific pursuits, without in the least making things clearer. Mr. James Geikie x says : * When I attended school, the text- books used by my teachers were about as repellent as they could be.' And at p. 1 2 : ( Great care, however, should be taken to avoid wearying the youthful student with strings of mere names.' When we find professors making fun of this so-called scientific 1 Fragments of Earth Lore, p. I. xxii STUDIES IN THE EVOLUTION OF ANIMALS terminology, we begin to hope that the tide may turn, and that we and future generations may yet be released from the mockery which some may think a good substitute for science. The pursuits of the specialists no doubt were a great induce- ment to coining new names for every cell, for every joint, for every limb of a Milliped, and so forth. This, however, is what Dr. Burdon Sanderson has said, in his inaugural address to the British Association in 1893 : Specialism advances knowledge at the risk of deteriorating the man, and tends to exaggerate the importance of one set of phenomena, simply because the bearing of another set is not seen in the course of that division of labour. Taking a philosophical view of any set of phenomena does not mean that you have never attended to detail by close inspection ; but it means that you are able to withdraw your mind to a distance from the detail, and so take a broader view of the whole landscape, so as to include more of creation at one time, and thus obtain a comprehensive view of the relativity of the detail. John Hunter said — ( Don't think, try.' He however not only tried, but also thought. The bane of modern life seems to be that there is too much trying, and very little thinking of what may happen ! We should now say — ' Think, investigate, imagine, and also try.' And when you get an idea into your head follow it up. If it is worth anything, and if it has any truth in it, and if you get rid of your mental inertia, and keep your eyes and ears open, you will be sure sooner or later to come across evidence in support of your idea. You have also of course to read and ascertain, if you can, what others have thought and have written on the same set of subjects. These are all various ways of ascertaining the truth, and of making sure that it is truth you are dealing with. We have been for centuries ' hag ridden ' by monstrous fictions, and it is certainly a comfort to emerge from the pressure of this INTRODUCTION xxiii deep sea of unrealities, and take a look round upon the upper world of realities. At the back of the phenomenon we call a Horse, a Cat, or any other animal, there is a whole chain of phenomena — its evolution —which in ancient time was not suspected. All this chain of phenomena, leading up to what you actually see, has to be dis- covered by the aid of the imagination, which does not always tell the truth. Without a free use of the imagination a dog is a dog, a cat is a cat, a cloud is a cloud, and nothing more. They are facts, like so many soldiers scattered on a field of battle without discipline or organisation. The function of the imagination is to group these scattered units into companies, regiments, and armies, and fight imaginary battles with them, all manoeuvred by a general called ( Logic/ who has his eyes open, and insight to discover what is going on around him. What this general has to be particularly careful about is, not to let his imagination wander loosely, and see all sorts of things that are not justified by ascertained facts. Some persons pride themselves upon not possessing any power of imagination, as if it were so very meritorious a feature of their ' grey matter.' They say they deal exclusively with facts. They do not, however, see that through this deficiency they lose that insight which is the work of what we call the imagination, and so they fail to notice what is behind the facts. They may perhaps not be aware that a great deal of the charm of life consists in possessing a vivid imagination, provided the possessor of it is able to keep it under control. By this faculty we are enabled, in a way, to picture what would otherwise be a wholly invisible past world. To exercise the imaginative power is to cultivate a most useful implement of research. There is so much to learn in one's short life. Every branch of xxiv STUDIES IN THE EVOLUTION OF ANIMALS Science is being studied with such minuteness that the help of the imagination is largely needed, not only to understand the pheno- mena yourself, but to make them clear to the imagination of other people. But note this : the grey matter of the human brain is a very treacherous informer. It invents a lot of things which it preaches unhesitatingly as truths, and then, after-generations have the task of sifting the whole, and re-classifying the supposed phenomena into truths, sub-truths, and lies ! In the course of these pages I have mentioned that the colora- tion of the skin of animals may have been greatly influenced by the electricity of the brain-cells. You might naturally ask — What has electricity to do with the colouring of animals ? But just think of it, and tell me where electricity does not come in. The modern view of electricity is that you cannot touch anything, you cannot move anything, you yourself cannot move, or cannot think, or will, without the evolution of electricity. If I blow on my hand, the impression on my skin is electrical, and is conveyed through my nerves to my brain, and there either develops thought, or both thought and action. One should have heard Professor Oliver Lodge on the evening of the ist June ISQ4,1 at the Royal Institution, and have seen him make experiments to illustrate the Hertz waves, in order to realise how completely the nerve-centres of animals are in the grip of their surroundings, taking of course the visceral impressions as part of the surroundings. Just as one Leyden jar in action influ- ences another wholly disconnected with it, except through the means of the ether, but attuned to it, and sets it in motion ; just as one tuning fork in vibration sets another in action which is in unison with it ; just as one magnet influences another near it, so everything — light, heat, magnetism, electricity, gravity, etc., act on 1 Lecture printed in Nature of 7th June 1894, p. 133. INTRODUCTION xxv the sensitive nerve-matter of the nervous system of animals, and influence thought and all other nerve-action. Several branches of animals evolved from other animals which were not stationary, but were changing. While changing, they in turn were evolving others in various ' grooves ' of evolution. This would account for the fact that although their descendants have several characters in common with the ancestral stock, they are nevertheless widely distinct in other characters ; and the characters they mostly differed in were exactly those which depended on the influences of surroundings for their development, and therefore were greatly modified by them. There is another point about which zoologists seem to have no doubt. Mr. Herbert Spencer l says : * Zoologists are agreed that the Whale has been evolved from a mammal which took to aquatic habits, and that its disused hind-limbs have gradually disappeared.' Many others have also the same belief; for Mr. Hutchinson2 says : * Take for example the case of Whales and fishes ; the original land mammal from which Whales are descended has in o course of time become so fish-like in appearance that even in these modern days there are some who yet speak of them as fishes ! The shape of the Whale is fish-like; it has lost its hind-limbs through disuse : it has changed its fore-limbs into paddles, which have a certain fin-like aspect ; and its cousin, the Porpoise, has developed a big triangular fin on the back.' All this derivation of water mammals from land mammals alone may be true or untrue. In the words of Mr. Hutchinson : ' What right has any one, however great his knowledge or his ability, to dictate to Nature, and to say this or that is impossible ? ' 1 ' Rejoinder to Professor Weismann,' Contemporary Review, December 1893, P- 9°9- 2 Creatures of Other Days, p. 131. xxvi STUDIES IN THE EVOLUTION OF ANIMALS I confess that this theory which considers the fish-like mammals as having descended from land mammals which took to aquatic habits does not seem to me satisfactory. Zoologists would appear to have conceived a roundabout way of evolving a Whale. The fish is made first to evolve a land mammal, and then this takes to the water again and gets rid of its hind-legs. It seems clear to me that if the fish proper could evolve a land mammal, it could also evolve a water mammal, without the necessity of going through this roundabout performance. If a bird could lose its fore-limbs on land, it would appear that a Whale could lose its hind-limbs in the water. This notion presupposes the possibility of land mammals evolving from fishes, and the impossibility of water mammals evolving from the same fishes. And all this in face of all we know about the Ichthyosaurs and Plesiosaurs, with their dwindling hind- limbs ; in face of the shore and land fishes hopping about on their pectoral fins on land, so that they are difficult to catch ; in face of the fact that certain fishes proper can breathe either by gills or by lungs, according to circumstances ; and in face of the fact, which every one knows, that the Tadpole is first fish-like, and then evolves arms and legs without getting out of the water. Are we so sure, in spite of ' agreement among zoologists,' that the Whales are degenerated land animals, and that land animals are not further evolutions of fish-like animals which have taken to life on dry land, while the Whale, evolving from the same fish-plane, remained a water mammal ? In the amphibians alone we have ample evidence that a fish- like vertebrate can grow arms and legs without leaving the water ; and in the Ichthyosaurs we have again ample evidence that the hind-limbs were already undergoing degradation, and that in the Plesiosaurs both the hand and foot had become degraded to INTRODUCTION xxvii five digits, instead of the many digits of the Ichthyosaur form. I think no one has ever credited these extinct animals with having been first land animals which took to a water life. There is, more- over, some evidence in favour of considering them mammals. Professors and authors would seem to have stereotyped on our brain the words * normality/ ' anomaly,' ' monstrosity,' giving them certain arbitrary meanings. They perhaps may have thought that they had settled all matters regarding creation, as far as such phenomena were concerned. But let us imagine that anomalies and monstrosities may possibly have been ' factors in the origin of species.' Then we begin to see that the method of creation will appear under a somewhat different aspect from what books and professors have taught us. Under the heading of * Monstrosities,' I have discussed these particular phenomena, and have endeavoured to show that what we call monstrosities may have been more frequent factors in modifying the structure of animals than has been supposed. As the whole arm can be suppressed in one birth, so, I imagine, could the Archeopteryx have had its long tail shortened to the little stump of the modern bird in one birth. The objection to such a sudden transformation seems to rest only in the minds of those who have worked up into an unalterable dogma the notion that modifications in organisms are brought about solely by slow degrees. This dogma may possess no unalterability outside the brain of scientists. It might be said, if this were so, the long tail of the Archeo- pteryx would have revealed itself sometime by a sudden reversion. But reversions in some organisms either rarely happen, or do not happen at all, and if they do happen, sometimes they may escape notice. For instance, no botanist doubts that the leaf of the orange and xxviii STUDIES IN THE EVOLUTION OF ANIMALS lemon trees is the middle leaflet of some ancestral form with three leaflets, like that of Citrus Trifoliate/,'}- yet the one leaflet persists through millions of generations without reversions. In India, in my researches on the oranges and lemons, I sowed seeds of all kinds of Citrus, and only a. few seedlings gave any indication in their first leaves of having descended from a trifoliate ancestor.2 Evolutionists do not believe that modern birds evolved from the extinct Pterodactyle form. Yet what is more easy than for a pterodactyle wing-membrane to grow hair, like other parts of the body ; and for this to become exaggerated into feather-like hairs, and so on ; then for the wing-membrane to contract, perhaps even in one generation, so as to envelop the arm and finger-bones, while the feathers increased in size, and became the real flying apparatus ? All this seems certainly preposterous and fanciful to a person who may have looked upon monstrosities as ungodly phenomena, but as they do occur now, there is no reason to suppose they did not occur in past ages. The animal congenitally is given a certain bodily structure whether normal or abnormal. He, that is, his nerve-centres, must make the best of it, if he is to live at all. He has, moreover, to regulate his actions and habits by the growing structure of which he is possessed, until they become established by the completion of that growth in adult age. He is the sport of inheritance and surroundings. Inheritance tends to keep him on certain more or less fixed lines, but it does not at all follow that circumstances may not change his structure to a large extent in one birth, so as to shunt his descendants on to a new line. We know that all mammals are allied, for if they were not, 1 See Gardeners* Chronicle of i8th November 1893, p. 625. 2 See Oranges and Lemons of India and Ceylon^ pi. 246. INTRODUCTION xxix they would not have the same plan of skeleton, and the same apparatus for nursing their young. Besides nervous, circulatory, and other structural features, which mammals have also in common, there are dermic features which, I think, have not been hitherto sufficiently recognised by biologists as indications of derivation. I mean the markings on the exterior of mammals. Of course every one knows that Leopards and Spotted Cats are allied, but probably few suspect that the spots on Leopards may indicate a distinct derivation from animals which have no spots. I don't mean with Lions and Pumas and other individuals of the Cat tribe, but with animals wholly distinct from these, and even with certain extinct animals. In works of comparative anatomy, professors show that the internal structures of mammals — bone for bone, muscle for muscle —are identical. Then whence comes all this difference of ex- ternal surface? How comes it that the Leopard is rosetted, the Cheetah spotted, the Tiger and Zebra striped in one direction, while the Ocelot is striped in another direction, and so forth? Evolutionists declare that these external colours and markings have been brought about by adaptation to surroundings. In the following pages I have discussed what modification of this theory is, in my judgment, needed in order to make it conformable to all the facts that I shall place before the reader. When we first begin to study the spotting and striping of animals, they seem a chaos of markings, unregulated by any laws ; but by degrees we become aware that there is some method in the whole phenomenon, and the markings of one animal can be seen to be derived from those of another, just as in the skeleton we see each bone to be derived from that of an ancestor. If not all, most of the spotted and striped mammals, more especially the carnivora, are reducible more or less to one plan of origin. xxx STUDIES IN THE EVOLUTION OF ANIMALS The bibliography of spots and stripes is not very abundant, and biologists may perhaps have depended a little too much on natural selection, as being sufficient to explain the creation of everything. The scope of some of the following studies is to show that the spotting and striping of mammals, in their origin, are not purely the results of natural selection from beginning to end. I believe them to have been originally inherited features, coming from very remote ancestors, and altered in many ways by transmission from species to species, from genus to genus. So many persons are interested in Horses that to understand in some way the origin of their curious markings would add to the interest of these animals. Similarly it would add to the interest we take in our domestic animals, if we could satisfactorily account for the spotting and striping of our Cats and Dogs, and other mammals. Our surroundings would again become peopled with the remote and extinct ancestors from which those we now see have descended. The evolutionist with his * eyes open,' can find interest in Leopard skins, in the dapples of Horses, and in the markings of other animals ; in the coloration of the legs of Horses, Dogs, Cats, and in a hundred other things which the non-evolutionist would pass by as ordinary insignificant phenomena, and totally void of interest. Fifty lives would not suffice for the evolutionist to exhaust the interest of things he may see around him. It is all a study of the real method of creation. It is usual for people to think of the Horse as an animal fit for draught, for riding, hunting, racing, etc., but the evolutionist sees both in his internal structure and in his external coloration, relation- ships to animals which ordinary people think have nothing to do with the Horse. We shall see that rosetted animals must have been legions INTRODUCTION xxxi in past ages, and of all kinds and descriptions. The coloration of the skin is not a thing that can be fossilised, and so one has to put ' two and two together ' in order to discover an explanation for the varied markings of the mammals of our day. We not infrequently pass over the seeming, and go a-hunting after the obscure and the unlikely. It seems to me that the organs of animals which receive and store up impressions, which we call nerve-centres, are as much engaged in influencing the form and coloration of the markings of the skin as they are in moulding and modifying the skeleton and other parts of the body. They are the controllers and regulators of the whole life, not only of the individual but also of the race. And the individuals forming a race were after all part and parcel of the ancestral stock, and were at one time or other organically con- nected with it. I do not, however, pretend in these pages to account for every speck and coloured hair, but to give my view of what seems to have been the genesis of spots and stripes in mammals, and of the contrasted coloration we see in so many animals, which would indicate some sort of plan of coloration. I do not enter into the microscopy of the subject — into how pigment cells behave in fishes, and other small animals which change their coloration and spotting according to surroundings. We know that the Leopard, the Tiger, the Zebra, and others do not do so, and there- fore we have to account for the genesis of their more or less permanent spots or stripes. My suggestion would appear to be a ' vera causa ' of the markings of the Jaguar, the markings of all other mammals, in cases where these exist, being only a modifica- tion of such rosettes as those of the Jaguar, and its markings only a modification of vastly more ancient conditions. One of the problems to be solved is — How came the rosettes on xxxii STUDIES IN THE EVOLUTION OF ANIMALS the Jaguar, the stripes on the Tiger and Zebra, the dapples on the Horse into being? Undoubtedly they must have some reference to ancestral features. What ancestor or ancestors have these existing features been inherited from, for assuredly they present evidence of inheritance as much as the bones of their skeletons ? We should make a distinction between the general coloration of an animal and its spot or stripe colouring ; both are liable to vary independently. The Cheetah, the Dalmatian Dog, and certain Horses and other animals are black-spotted ; while certain Deer, Phalangers, and certain Horses are white spotted. Fossils certainly give us the structure of extinct animals, but I hope to show that they can also tell us something, if not so certainly, about the probable origin of certain markings we see on existing animals. But in order to see all this a good deal of the imaginative faculty will have to be brought into play. Probably zoologists may look upon the markings of animals as trivial and unimportant features, yet it would seem that markings, if not the general coloration, are important zoological features, and may tell a tale as interesting as that told by the teeth. Of course skin coloration and markings are more liable to change, because they have to adapt themselves perhaps more intimately to the surroundings in which the animals happen to move. Great importance among zoologists seems to be placed on the character of the teeth of animals in grouping them for the purposes of classification, as if these were absolutely the only characters that are inherited. The reason why so much importance has been given to teeth as a character indicating descent is that fossil vertebrates have rarely anything but their simple skeleton to show what they may have been like, and certainly the teeth may indicate their habits. The skin characters have usually wholly disappeared, and we have INTRODUCTION xxxiii nothing to guide us, in that direction, but the skins of existing animals. There is, however, some evidence which would tend to make us suspect that teeth may be liable to sudden changes, owing to con- traction of the jaws. Teeth, like other bones, it would appear, are subject to fusion or to dissociation, as the case may be. And the writer on Seals in the Royal Natural History quotes an interesting example of dissociation in teeth, which I have quoted more fully in another place, as I think it very instructive, and the inference to to be drawn from it important. The doctrine of evolution has replaced every other doctrine of creation, owing to the undeniable support that existing facts give it. This being unstintedly admitted by all modern scientists, and by many modern theologians also, there remains only to account, in some way, for the appearance on this earth of the innumerable creatures we see, including man himself, by the method of evolution. Lower down in the scale of life, beyond a certain stage, we cannot go, in this investigation, because breaks occur which are at present in no way filled up. Whether the gaps may or may not be filled up at some future period no one living can say. The evolution of the structure of one kind of animal from another has been made clear enough, but the evolution of the coloration of one kind of animal from another has not been made sufficiently clear. Probably this feature in evolution has been neglected, because it offered difficulties which perhaps looked like puzzles. It is this feature of evolution which I have tried to make clear in some of the following pages. With regard to drawing conclusions, Professor Huxley x remarks :— ' What in fact lay at the foundation of all Zadig's arguments 1 'On the method of Zadig,' Science and Hebrew Tradition, pp. 7 and 8. C xxxiv STUDIES IN THE EVOLUTION OF ANIMALS but the coarse commonplace assumption, upon which every act of our daily lives is based, that we may conclude from an effect to the pre-existence of a cause competent to produce that effect. ' Zadig was able to do this because he perceived endless minute differences (and likenesses) where untrained eyes discern nothing ; and because the unconscious logic of common sense compelled him to account for these effects by the causes he knew to be competent to produce them.' SPOTTED AND STRIPED MAMMALS (HORSES E X C E P T E D) ' VET, if he would be guided by the true spirit of scientific inquiry, he must maintain an unsettled opinion as long as the evidence is incomplete or contradictory ; he must adopt conclusions only where the evidence is complete and convincing ; he must ever hold his mind open to new evidence, even if it bring about the abandonment of accepted beliefs. He may, if desirable, quote the conclusions of others, and, if well read, he may thus become widely informed ; but he will fail to gain the best benefit that comes from careful study, if he does not reach opinions and conclusions for himself, forming them only as fast as the evidence that may support them is clearly understood.' Elementary Meteorology ', by Prof. W. M. DAVIS. PART I SPOTTED AND STRIPED MAMMALS (HORSES EXCEPTED) A GLANCE at the living Mammals in the gardens of the Zoological Society, and at the mounted specimens in the Natural History Museum, will show us what a large number of Mammals of several orders and of many genera are either spotted or striped, or both spotted and striped. There is a large number of Mammals which may be said to have permanently lost their spots or stripes ; but there are not very many which, either in the childhood of the individual or in some of its species, either on the legs, on the tail, or on other parts, do not betray their descent by vestiges of either spots or stripes. In the Appendices I have given lists of various Mammals which show spotting or striping now, or show vestiges of descent from spotted and striped ancestors. Some of them have a plain body and spotted or striped legs ; while others have only a ringed tail to show what they came from. These tail rings, even when they are the sole markings, are in my opinion dis- tinct vestiges of either a spotted or striped ancestry. If one had a fuller acquaintance with the childhood and adulthood of all Mammals, under different conditions of climate and other surroundings, the probability is that these lists might be much lengthened, and we might perhaps then come to the conclusion that most Mammals, at least, had a spotted ancestry more or less remote, not even excluding the Marsupials of Australia. The earliest record that I have met with of a striped Mammal is that shown in Fig. I. It is the bone handle of a poignard of a prehistoric period. It represents some kind of deer which had partial broad stripes on its flanks, evidently ves- tiges of something like the FIG. i. — Cast of a handle of poignard found at , . , Bruniquel, on the river Aseyran, France. (Brit. zebra bands in the Same Mus. : Mammoth and Reindeer period. ) regions It might perhaps be thought, as an alternative, that these marks were not intended by the carver to indicate skin -stripes, but merely the projections of the ribs. If, however, we consider that, if the prehistoric savage knew anything, he must have known a great deal about the ribs of the animals he was continually hunting, cutting up, and feeding upon, we shall see that he must have known that the ribs of the deer did not extend to its haunches. Therefore, the transverse stripings on this ancient model of a deer can hardly be taken to have been meant to indicate the projections of the ribs, but are more likely to have been meant for skin-stripes. Moreover, if the reader will turn to Appendix A, Fig. 22, he will see an antelope with striping not very unlike that of this prehistoric relic. I shall, however, leave this point to be decided by archaeologists and palaeontologists, and proceed with my story. What causes the changes in the markings of different animals, and at different ages, I do not know. Presumably atomic changes in the nerve centres, initiated by surroundings, heredity, or what SPOTTED AND STRIPED MAMMALS 5 not, become reflected electrically on the skin, whether during the embryonic stage or afterwards, and cause aggregation or dissociation or other changes in pigment cells. Evolutionary biologists — and probably there are at present few or no biologists who have not accepted the doctrine of Evolution — seem inclined to consider that these markings in animals are the result of natural selection, acting cumulatively on some fortuitous variations that may have occurred, and do occur, in an infinity of ways. By natural selection is meant the weeding-out, generation after generation, of all those varia- tions which are insufficiently protected by their surroundings for either offence or defence, or both, and by keeping alive those which are most fit. Reproduction and heredity then maintain and improve this selection. Dr. Alfred Russel Wallace says l that ' Professor William H. Bremer of Yale College has shown that the white marks or the spots of domesticated animals are rarely symmetrical, but have a tendency to appear more frequently on the left side. This is the case with Horses, Cattle, Dogs, and Swine. . . . Among wild animals, the Skunk varies considerably in the amount of white on the body ; and this, too, was found to be usually greatest on the left side.2 A close examination of numerous striped or spotted species, as Tigers, Jaguars, Zebras, etc., showed that the bilateral symmetry was not exact, although the general effect of the two sides was the same. This is pre- cisely what we should expect if the symmetry is not the result of a general law of the organism, but has been, in part at least, produced and preserved for the useful purpose of recognition by 1 Note to p. 217, Darwinism. 2 I should say this is a sure indication that the difference does not depend on the skin, but on the unequal action of the two halves of the nerve centre. 6 STUDIES IN THE EVOLUTION OF ANIMALS the animal's fellows of the same species, and especially by the sexes and the young.' l Then on p. 199, quoting from Major Wai ford, a Tiger-hunter, Dr. Wallace says : ' There can be no doubt whatever that the colour of both the Tiger and the Panther renders them almost invisible, especially in a strong blaze of light, when among grass ; and one does not seem to notice stripes or spots till they are dead.' I suspect the 'strong blaze of light' had something to do with the invisibility on the part of Major Walford, for he says that natives could see the Tiger, which would seem to mean that their eyes are accustomed to strong light, and can adapt them- selves to it There cannot, however, be any doubt that the two sides of a spotted or striped animal are unsymmetrical. A glance at the Tiger and Leopard skins in the London fur-shops would be enough to convince any one of this. And it is, I think, due to a want of identical nervous action in both halves of the central nerve organ, to the atomic action of which I would attribute all skin colorations. One of the objects of these pages is to investigate how far the markings of animals are due to natural selection, and how far they are not. The innumerable variations in the markings of horses, which we see in the streets of London, will be made to contribute evidence in this interesting investigation. In many cases it will not be difficult to show that the striped animal is only a modification of the spotted animal. 1 The probability is that wild animals recognise their fellows more by scent than by sight : nevertheless, it is curious to note how dogs recognise dogs of any breed, at a distance ; they, however, complete their investigation by means of the nose. SPOTTED AND STRIPED MAMMALS 7 We shall first examine some of the most markedly spotted and best-known animals, viz., the Jaguar, the Leopard, the Cheetah, the Ocelot, and the Serval. For my purpose the Jaguar and Leopard, and also the Panther, may be considered as one animal, the others being differently marked. Mr. G. P. Sanderson l says : * The distinction between the Panther and Leopard is practically small, and lies chiefly in the inferior size of the Leopard. The markings, habits, and general appearance (except size) of the two animals are almost identical. But neither can be confounded with the Cheetah,, even by the most casual observer . . . the spots of the Panther and Leopard are grouped in rosettes, enclosing a portion of the ground colour ; 2 whereas those of the Cheetah are solid, and are separate from each other.' Mr. Blandford3 declares that there is no difference whatever between the Panther and Leopard, and Mr. Blyth was of the same opinion. He also states that black and ordinary Leopard cubs are often found in the same litter, and that an albino Leopard is figured in Buchanan Hamilton's drawings. Mr. Sanderson further states that the black Leopards from Java have all sorts of shades, from jet-black to light brown ; and that the black Leopard seems to be confined, at least in India, to heavy forest tracts, while the common variety in Mysore frequents open country, and also rocky localities. It should be here noted that in black Leopards, as in certain black Cats, the markings are often plainly visible in certain lights. The marking is persistent, and quite independent of melanism, or that condition which produces the general blackness of the skin. 1 Wild Beasts of India, p. 327. 2 Sometimes of a different shade from the ground colour. 3 Mammals of India, p. 68. 8 STUDIES IN THE EVOLUTION OF ANIMALS The Jaguar is only a South American Leopard, and black varia- tions of it are frequent also there. It may be interesting to note that the black Leopards of Africa differ somewhat from the black Leopards of Asia. The Royal Natural History, vol. i. p. 338, regarding the black African Leopards, states that in 1885 a black specimen, obtained near Grahamstown, was described by Dr. Giinther. Its ground colour was a rich tawny, with an orange tinge ; but the spots, instead of being of the usual rosette-like form, were nearly all small and solid, like those on the head of an ordinary Leopard. In the black Leopards of Asia the rosettes are retained, while in those of Africa they appear to lose their ocellus and become solid. The jet-black Leopards, like the jet-black domestic Cats, usually lose all traces of markings. Leopards and Jaguars are tree-loving animals, and therefore it seems obvious to evolutionists that their markings were the result of natural selection, acting cumulatively on favourable variations so as ultimately to harmonise them with a surround- ing of speckled lights and shades produced by the leaves of trees. Unlike the Lion and the Tiger, the Leopard of India is 'thor- oughly at home in trees, running up a straight-stemmed and smooth- barked trunk with the speed and agility of a Monkey ' ; * and Mr. Hunter remarks that in Africa ' the Leopard nearly always puts the remains of his " kill " up a tree/ 2 Then the Jaguar * is one of the most expert climbers among the larger Cats ' ; 3 and during inun- dations it is said that it will sometimes take to an arboreal life, preying upon Monkeys. So we see there is ample evidence to show that the Leopards 1 Roy. Nat. Hist., vol. i. p. 390. 2 Ibid. p. 392. 3 Jbid. p. 395. SPOTTED AND STRIPED MAMMALS 9 have their markings in harmony with the surroundings of an arboreal life. :m*ifcZi& * FIG. 2. — Jaguar, from a photograph by Gambier Bolton, F.Z.S. FIG. 3. — Leopard, from a photograph by Gambier Bolton, F.Z.S. A glance at the markings of the Jaguar and Leopard in Figs. 2 and 3 will show that a large number of their rosettes is made up of groups of small spots, each group forming an isolated and io STUDIES IN THE EVOLUTION OF ANIMALS irregular ring of small black spots with an enclosed space. This space may be either of the same colour as the general ground of the skin, or of a darker shade, and sometimes of a different hue. Moreover, on the Jaguar skin (Fig. 4) there are many rosettes which have one or more small black specks in the middle of the enclosed space, which in Leopards proper seem to be obliterated, owing perhaps to a contraction of the entire rosette. In the Tring Museum there is a fine specimen of a Jaguar. On its flank are very large polygonal rosettes, with from one to six specks in the enclosed space. If any one will take the trouble to look over the Leopard skins in the windows of the London furriers, he will be at once convinced that the rosettes even in the same skin vary immensely ; * and if different skins are compared it will be found that, although the general mapping may be similar, the detail shows that there are scarcely two skins alike. Indeed, the skins are as different as the faces one sees among the people in the crowded streets of London. It seems astonishing that, among the thousands of faces one sees, there should not be two alike. It is the same with the coloration of most animals. Then, if we examine the skins of Mammals which are sup- posed to be of different species, although of the same genus, we find astonishing modifications of what I consider the typical rosettes of the Jaguar. A very interesting monograph of the FelidcB by D. G. Elliot shows, by means of the beautifully coloured plates, not only the modifications of rosettes, but all manner of intermediate stages up to total obliteration of all markings. The transitions from rosettes to spots and stripes can there be readily seen. 1 A variety of Jaguar from Mexico is characterised by the distance at which the small spots which ordinarily constitute the rings are placed from one another, so that complete rings or rosettes of spots only occasionally occur. Roy. Nat. Hist., vol. i. p. 395. SPOTTED AND STRIPED MAMMALS n I can only give a small number of Cats in this superb mono- graph, to show the principal variations from the typical rosettes of the Jaguar. In Elliot's Jaguar (Felis onca\ which presumably was copied from nature, there are on the .flanks very distinct rosettes, made up of polygonal rings of black spots, more or less fused, and enclosing a space which is differently coloured from the inter- rosette ground ; and each rosette has a distinct black speck in the centre of the enclosed space. Then his Margay (F. tigrind] is of a Leopard-yellow colour, resetted in various ways, the rosettes being made up of three, four, and five black spots, which enclose a brown space. It is, more- over, distinctly barred on the shoulder and back. (See another variant on p. 418 of Roy. Nat. Hist., vol. i.) Fontanier's Spotted Cat (F. tristis] is something like a Jaguar, but its rosettes are distorted in various ways. From this we pass to his African Golden Cat (F. chrysostrix], which is either grey or brown trimmed with Leopard-yellow. Its spots are solid. The Serval (F. serval} is much the same ; only, in addition, it has fusions of spots into longitudinal streaks.1 The Rubiginous Cat (F. rubiginosd] is of a brownish-grey, with solid black spots arranged in longitudinal rozvs, preparatory to fusing in longitudinal stripes, like those on the back of the neck. We come then to the Pampas Cat (F. pajeros}. It has brown longitudinal bands on grey ground, in the manner of the Ocelots, and the legs are transversely banded. (See variant of this on p. 431, Roy. Nat. Hist.) The Clouded Tiger is very interesting (F. diardi]. It has a 1 The Serval is also subject to melanoid variations, and the spots are distinctly visible when viewed in certain lights. (Roy. Nat. Hist., vol. i. p. 414.) 12 STUDIES IN THE EVOLUTION OF ANIMALS yellowish-brown general colour, with broad transverse patches of a yellowish-grey, margined with black blotches or spots. The patches are evidently fusions of several rosettes of a similar colour. The haunches are resetted, and the tail has its rings double, which is also a vestige of a resetted body. There is another much like the foregoing, the little Marbled Tiger (F. mannorata).1 It is either Leopard-yellow or grey, with large clouded patches edged and spotted with black, while the general colour is paler. Its haunches and shoulders are spotted. The tail is either spotted or ringed. We come now to the Caffer Cat (F. caffra), which is of a bluish-grey, striped with black, Tiger-fashion. (See variant on p. 421, Roy. Nat. Hist.) From this we pass to the Tigers, which every one knows. We pass, then, to total obliteration of spots and stripes in the self-coloured Cats, like the Puma (F. concolor), which is also called Cougar, Panther, and American Lion. In the adult stage it is all plain, and of a rich brownish-grey, but its kittens are spotted. How astonished the Puma must be when she has cubs for the first time ! She looks at her husband's coat and at her own, and sees them of a uniform rich isabelline colour, and then she finds her kittens are born spotted all over like young leopards. Are these really my children ? Yes, your very own ! You have succeeded in shaking off your rosettes, but your kittens still masquerade in that antiquated dress, and prove to you that after all your pedigree is identical with that of the Leopard ! There are innumerable transition markings between rosettes, solid spots, and stripes, and many Cats have only vestiges of spots or stripes. The tails of most of these Felidce are ringed, and the 1 In the Roy. Nat. Hist, these are called Clouded Leopard and Marbled Cat. SPOTTED AND STRIPED MAMMALS 13 under surfaces of most of them are paler than the back and flanks, and in some cases wholly white. Elliot's monograph of the Felidce contains gradations, modifi- cations, and transformations of rosettes and spots, which can be studied with comfort within the compass of a book. It is like a museum of Cats. To facilitate the examination and comparison of Leopard and Jaguar rosettes, and to show both flanks at one glance, I have given in Figs. 4-7 some skins spread out ; and Fig. 59 gives a number of variations of single rosettes taken from numerous Leopard skins. It will be seen that on the Jaguar skin there is a large number of rosettes consisting of an irregular or polygonal ring of small spots enclosing a space, in the middle of which, as I said, there are one or more specks. At times the ring-spots are dissociated, as on the shoulder, and they appear like an irregular group ; at other times the ring-spots coalesce wholly or partially, and form a more or less continuous polygonal ring, as in those of Fig. 7, with or without the central specks. The rosettes of what are commonly called Leopards are usually without the enclosed specks. This continuous ring can best be seen on the Leopard skin of Fig. 7, already alluded to. Again, we see that on the abdominal surface the rosettes tend to coalesce further, with obliteration of the enclosed space, and, in the Jaguar, to form a sort of trefoil, quadrifoil, pentafoil, etc. I would here note that on the tails of these Leopards the rosettes, at first isolated, tend to coalesce and form transverse rings towards the tips, with obliteration of the enclosed space ; and that along the spine the rosettes tend to coalesce longitudinally, and to form a continuous dorsal line or band. All variations of Leopard rosettes would seem to be modifica- FIG. 4. --Skin of Jaguar, from a Photograph by Messrs. Dixon and Son, Skin lent by Messrs. Jeffs and Harris. FIG. 5. — Skin of Leopard — may be African ; from a Photograph by Messrs. Dixon and Son. Skin lent by Messrs. Jeffs and Harris. FIG. 6. — Skin of Leopard — probably Chinese ; from a Photograph by Messrs. Dixon and Son. Skin lent by Messrs. Jeffs and Harris. FIG. 7. — Skin of Chinese Leopard, from a photograph by Messrs. Dixon and Son. Skin lent by Messrs. Back and Co. B i8 STUDIES IN THE EVOLUTION OF ANIMALS tions of those on the flank of the Jaguar ; and Fig. 4 shows many intermediate forms between the Jaguar rosettes enclosing specks and the solid rosettes or spots of the abdominal region. In one particular Leopard skin l I noticed a very curious varia- tion, shown in Fig. 8. It appeared /n /Vj rpv> 0) x— ^\ as if the enclosed specks had been 0 o a ° a p extruded from the rosette ring. \)> o r^ In some regions it is not always easy to make out whether the FIG. s.— Occasional variants of jaguar rosettes are a coalescence or a dis- and Leopard rosettes. . . _ sociation ol spots/ Fig. 9 shows rosettes from the scapular regions of a Jaguar skin. Some look like a consolidation and others like a dissocia- I e? CD * - FIG. 9. —Various forms of rosettes from the scapular regions of a Jaguar skin. tion of spots. The groups shown in Fig. 59 (Nos. 30-32) are obviously a dissociation of the ring-spots. The Jaguar in the Science and Art Museum, Edinburgh, has the spaces enclosed by the rosettes of the whole skin of a deeper shade of fawn than the general ground colour ; and on the hind-legs 1 Shown to me at Messrs. Back and Co.'s. 2 Two Leopards, described by M. A, Milne Edwards, ' were remarkable for the circumstance that the markings on the flanks were more like rings than rosettes' (p. 390, Roy. Nat. Hist. vol. i.). SPOTTED AND STRIPED MAMMALS 19 it has fusions of the ring-spots into bigger spots or blotches, with a deeper shade of fawn colour between them than the general fawn colour. I have endeavoured to show this in No. 9, Fig. 59. Moreover, some Leopards, such as that of Fig. 6, have large solid rosettes of irregular shape on their haunches, while those on their flanks are ocellated. This, I think, is clear evidence that, in these cases at least, the haunch rosettes are mere contractions of the larger typical rosettes on the flanks. A glance at the Jaguar skin of Fig. 2 also shows distinctly that the enclosed spaces of the rosettes are of a deeper shade than the general colour between the rosettes. I mention these details because in these Mammals there appear to be three distinct colorations, viz., the colour of the inter-rosette spaces, of the rings, and of the enclosed space. All three may vary independently of the others, not only in colour, but also in form. The different colours of the inter-rosette spaces, of the spots, and of the enclosed spaces, would seem to indicate that each has a separate and distinct nerve-centre, as much localised as the centres of the different parts of the arm, the leg, the face, etc., and that each of these components of the whole surface may vary independently of the others. It seems curious that the spots of the Dalmatian Dog should be black on a white ground, and those of the Phalanger and Dasyure white on a black ground. The general coloration of Mammals seems of little importance, as it varies in almost every individual ; what is tan in one may be either black or white in another. But the * markings ' and the colorations, which are seen to be like a sort of ' plan/ are of much greater importance, as they more or less indicate, I think, something inherited from very remote ancestors. Let us now take a look at a very differently spotted Mammal. 20 Fig. 10 shows the picture of a living Cheetah, and Fig. 1 1 the skin of a similar animal (perhaps an older one) spread out to see both sides at once. In the Cheetah we find numerous solid circular spots, with minute specks interspersed among them. The large spots are disposed in transverse rows on the flanks (Fig. lo).1 The minute specks, however, in the figure of the skin are inter- spersed among the larger spots, apparently without any order ; FIG. 10. — Picture of a living Cheetah, from a photograph by Ottomar Anechiitz, Lissa(Posen). while in the figure of the living animal the minuter specks appear to be disposed in many places in rows also, alternating with the rows of the bigger spots. In the Cheetah it is not easy to make out whether the larger spots are consolidations of the entire Leopard rosettes, or dissocia- tions of the spots forming the rosette rings of the Jaguar. The 1 At the International Fur Stores, Regent Street, I was shown a Cheetah skin with some of the rows on the flank undergoing fusion, and forming beaded strings ; and several couples of spots were actually fused into one blotch. FIG. it. — Skin of a Cheetah— perhaps of an old one ; from a photograph by Messrs. Dixon and Son. Skin lent by Messrs. Back and Co. 22 STUDIES IN THE EVOLUTION OF ANIMALS spots on the Jaguar's shoulder (Fig. 4) are evidently dissociated rosettes, while the spots on its hind-quarters and abdomen are evidently fusions or consolidations of rosettes ; so that the Cheetah spotting may have had either the one or the other origin.1 Anyhow, it is evident that the transverse strings of spots on the fore-legs of the Cheetah (Fig. 10) are homologous with similar transverse marks on the fore-legs of the Jaguar and other Leopards. As to the minute specks, I have a suspicion that they may have possibly resulted from the specks enclosed within the Jaguar rosettes. In the modifications which these animals have under- gone, the specks may have been extruded, as we have almost seen them do in Fig. 8, and have become disseminated among the bigger spots. A close scrutiny of the Cheetah spots may lead one to detect something like dissociated rosettes, especially on the right shoulder and haunches of the skin figure ; but on the haunches and tail of the living-animal figure the spots look more like consolidations of whole rosettes. There is no good reason why the characteristic spotting of the Cheetah should not be a combination of both processes, viz., dis- sociation in some parts and consolidation in others ; for in the same animal — the Jaguar — we find typical rosettes on the flanks, dissociated rosettes on the shoulders, and consolidated rosettes on the abdomen and legs. In certain Leopards the enclosed specks become entirely obliterated, while in the Cheetah these little specks may form one of its characteristic features. Fig. 59 (No. 35) shows four groups from the flank of a Cheetah ; and on the haunch of a Cheetah in the Natural History Museum, 1 Of two Cheetahs in the Tring Museum, one has isolated spots on half its tail, while the other has, in the same part, rings with scolloped edges, indicating a fusion of spots. SPOTTED AND STRIPED MAMMALS 23 as shown in Fig. 12, there is a similar disposition of large round spots and minute specks. From this one might perhaps surmise that the circular spots in the Cheetah * * represent the modified enclosed space of the • '•&&'*• Jaguar rosettes, while the specks represent . » the dissociated ring of spotlets. The ^ "^ change of colour of the enclosed space from . • brown to black is not wholly imaginary, FIG. 12.— Group of Spots for in horses we find that the white Spots fom the haunch of a Cheetah (Nat. Hist. Mus.). of dappled animals are changed to black spots in the roan and to brown spots in the strawberry roan.1 I confess, however, that the Cheetah spotting is rather puzzling, for the individual spots are as round as a shilling, with a general equality of size, and they do not give any indication of a coalescence of minor spots like those on the abdomen of the Jaguar. Yet the consolidated rosettes on the paws of the latter animal are not unlike those of the Cheetah. They have, moreover, minute specks among them. As spots can be wholly obliterated, so, I suppose, they can diminish in size. In a Leopard skin there were here and there minute specks, like those of the Cheetah, interspersed among the usual rosettes. This is uncommon in Leopard skins ; but in the Natural History Museum (case 1 2) a Leopard among the consolidated rosettes of its fore-legs has a number of minute specks like those of the Cheetah ; and in the window of the International Fur Stores I saw a Leopard skin which had small and roundish spots on the back (shoulder region) which were not unlike the larger spots of the Cheetah. So that it is not improbable that the larger circular spots of the Cheetah may 1 We may have melanism or albinism or shades thereof on the entire surface, or changes of colour in certain parts only, as I shall endeavour to show in another place. In another place I have also indicated that black, tan, and white are interchangeable colours. 24 STUDIES IN THE EVOLUTION OF ANIMALS be, after all, consolidated Leopard rosettes further modified into circular spots. On the other hand, Fig. 12 shows conditions which would suggest that it is the enclosed spaces of the Jaguar rosettes which become the large round spots of the Cheetah, while the specks are the dissociated rings of spotlets ; only the enclosed space in this case would be, as I said, changed from irregular brown to circular black. A very young Cheetah in the Natural History Museum (case 16 — Gueparda jubata], from the Cape of Good Hope, shows a very interesting variation. It is brown with faint spots, but what is still more curious is the fact that its o S? o " o ^b^ back is grey like that of a badger ! It may be of some interest to show ^ o° 0 0 how much variation the Jaguar rosettes FIG. 13.— Rosettes from a can undergo. Fig. 13 is taken from picture of the Jaguar in Griffith's j pictured in Griffith's Cuvier. C^lvlcrt p. 455, vol. n. » They may, perhaps, be closely matched from groups on the Cheetah skin of Fig. 1 1 . This much is clear to me, that the Cheetah and the Leopard are closely allied in habits and structure, and their spotting, how- ever modified it may have become, must have had one ancestral origin, not necessarily of course from the same individual, but from the same species of ancestor ; and that the difference in the existing animals comes from microscopical changes in the nerve- centres, which would result in pronounced differences on the skin. The student of animal markings would do well to study, as a previous training, the many-synonymed orchid — Odontoglossum crispum, and others of the same genus. Nothing is more interest- ing than a review of the variations of blotches on the petals of this genus. There are blotches of various sizes and forms ; there are cross-bars ; in some varieties there are single little spots on each SPOTTED AND STRIPED MAMMALS 25 petal ; and, finally, in others every trace of blotching or spotting disappears, and the whole flower is white, with a little lemon-colour on the lip. In the Dictionary of Gardening it is stated that ' it is a plant which varies to an almost endless extent, no two of the many thousands imported being perhaps exactly alike.' FIG. 14. — (a) Young and (&) Adult of Spotted Deer (Axis maculatus, Nat. Hist. Mus. ). Not impossibly, also, the stretching of the skin as the animal grows may, in some instances, tend to modify the grouping of the spots, and have something to do with dissociation. On the other hand, contraction of the skin in other regions may have something to do with consolidation of rosettes. Perhaps, in illustration of the former conditions, one might take the case of the Spotted Deer shown in outline in Fig. 14. The 26 STUDIES IN THE EVOLUTION OF ANIMALS young one (a) has its white spots close to each other, in some parts almost coalescing into blotches. Then as the animal grows the spots become more distinct, and in the adult they are separated by long intervals, as shown in (£). However this may be, we cannot ignore the fact that the whole physiology of the skin in Mammals, with its colourings and mark- ings, is under the control of the nerve-centres (perhaps as much as electro-plating is under the control of the battery or dynamo), and these again are under the various influences of heredity, age, varia- tions of temperature, climate, composition of the blood, and other surroundings, of which we know yet too little.1 In the various kinds of Leopards we see that not only the rosettes differ, but also the spaces between them differ much. These inter-rosette spaces run into each other, and form a sort of broad reticulation which is the ground-colouring of the skin. The Leopard of Kismaya, British East Africa,2 has its rosettes much closer than those of the Indian Leopard or of the American Jaguar, so that it seems much darker than they. The comparative smallness of this animal, supposing the number of rosettes to be equal, may, I think, sometimes account for the compactness of the rosettes, as well as for their elementary spotlets. At Mr. Rowland Ward's establishment, Piccadilly, I was shown a very small foetal Leopard, that is, in a stage before birth. It was closely spotted all over, but none of the spots were ocellated. Another young Leopard, but older than the preceding, had a com- mencing faint ocellus in some of its spots. On the other hand, a very 1 Orchids seem to undergo similar alteration in the spotting of their flowers, without any nervous influence that can be detected. Yet there must be some means of com- munication in the Dioncca between the bristles and the hinges of the leaf-blades, analogous to nervous or electric communication. 2 In the Zoological Society's Gardens. SPOTTED AND STRIPED MAMMALS 27 a Si •s young animal in the Natural History Museum (case 13), ticketed as a young Jaguar, has no spots at all, but is of a uniform brown. The variations in the disposition of the rosettes of Leopards are very considerable. In some specimens they are distributed irregu- larly, in others they occur in slanting rows, as in Fig. 1 5 (a). Where they are crowded, two or more fuse into an elongated ocellus, as in (£). The Fig. 59 shows how numerous are the variations in individual rosettes. We should make a distinction between the general colour and the spot or rosette colour ; both, as I said, are liable to vary inde- pendently. The Cheetah and the Dalmatian -p. 11 i , , i :Q' while the Deer is white- spotted. The ordinary Leopard has a general tan colour, the melanoid a general brown colour, and the Snow-leopard x a general white colour, although the rosettes remain black in all cases. 1 Of two Snow-leopards in the Tring Museum, one has ocellated rosettes, and the other has a large number of the rosettes solid, especially on the shoulders, haunches, and lower part of flanks. FIG. 15 — (Diagrammatic disposition of leopard mark- ings, both taken roughly from skins in furriers' windows. (a) Rows of rosettes, which might fuse into stripes. (b) Fusion of two or more rosettes. 28 STUDIES IN THE EVOLUTION OF ANIMALS In these variations we again find a parallel in Odontoglossum. Some species are pure zvhite, with maroon blotches, or spots, or bars, while others zxz yellow, with maroon blotching. The spots on the legs and tail of the Lion of Fig. 16 (a) leave no doubt that the ancestors of the Lion and Leopard were one. In adult Lions the rosettes become more and more obliterated, but in the young they cannot be mistaken for other than Leopard -spotting. The same may be said of the spots on the fore-leg of the Puma shown in Fig. 16 (V). In the Science and Art Museum of Edin- burgh there is a largish Cat, ticketed Puma, which may be a young one. It is of a light reddish-fawn colour,1 with distinct spots all over it of a deeper fawn. Its present general colour is not unlike that of the red domestic Cat. The Encyclopedia Britannica says : ' The young of the Puma, as in the case with the other plain-coloured Felidce, are, when born, spotted with dusky brown, and the tail ringed. These markings gradually fade, and quite disappear before the animal becomes full-grown.' Some varieties of Lynx, although their backs are plain, have spots on their abdomen and legs. These may be seen in the Natural History Museum. Then there is a large number of widely different animals, such as Racoons, Lemurs, and many others,2 which, although they have neither spots nor stripes on their bodies and legs, yet have distinct rings on their tails, like those of the Leopards and Tigers of our illustrations. Therefore, all these ring-tailed animals should, I think, be credited with either a spotted or a striped ancestry. In the Appendix I have given a list of animals, of very varied natures, which have ring-tails. They probably all descended from spotted ancestors, and the marks on their tails are the only vestige which now indicates the history of their ancestry. 1 Skins become faded in time. '-' See Appendix E. '.(*) FIG. 16. — (a) Lion, and (£) Puma, from photographs by Ottomar Anechiitz. 30 STUDIES IN THE EVOLUTION OF ANIMALS As to the markings of the Serval in Fig. 17, it is not likely that any one will take them for any other than consolidated Leopard rosettes placed widely apart, and in places arranged in longitudinal series.1 FIG. 17.— Serval, from a photograph by Ottoniar Anechiitz. In Fig. 1 8 is given a Marbled Cat, which, although ancestrally resetted, has its spotting undergoing obliteration, like the adult Pumas and Lions. We now turn to the numerous variations in the markings of Ocelots. 1 Note the black mark from the heel to the toes of hind-legs. It is an interesting feature, to which I shall refer in another place. FIG. 18. — Marbled Cat : on the flank it has distinct rosettes, and on the legs transverse stripes. From a photograph by Ottomar Anechiitz. 32 STUDIES IN THE EVOLUTION OF ANIMALS Fig. 19 (a) shows one variety in which the typical Leopard rosettes are plainly recognisable, only they are arranged in longi- FIG. 19. — Two distinct variations of Ocelots, from photographs by Ottomar Anechiitz. tudinal order, and on the flanks and shoulder the rosettes coalesce into parallel bands, with the enclosed spaces also continuous. It should be noted that on the shoulder of this Ocelot there is a tendency to dissociation of the rosette-spots. Then in Fig. 19 (b) we have an Ocelot in which the same character is intensified and further modified, the enclosed spaces being of a different colour from either the rings or the general ground-colour. In the Natural History Museum there are some Ocelots which show a further coalescence of the rosettes into more perfect longi- ir FIG. 20. — Diagrammatic sketch showing transformation of Ocelot rosettes into longitudinal bands : — (a) Rosettes arranged in longitudinal rows. (b] Their upper and lower segments fusing. (c\ The rows of rosettes completely fused into bands of a brownish colour, margined with black. (d) A row of rosettes from the flank of a Leopard skin ; these might readily fuse into twin stripes, as seen in Fig. 24. tudinal bands, in which the traces of the Leopard rosettes are almost wholly obliterated ; and it would not be easy to conceive how they originated, without knowledge of other varieties of Ocelots which indicate the steps leading to the longitudinally banded Ocelot. In Fig. 20 I have endeavoured to give a rough sketch of the passage from the Jaguar rosettes to the longitudinal parti-coloured bands of certain Ocelots. C 34 STUDIES IN THE EVOLUTION OF ANIMALS The shading of a, b, c is intended to show the brownish colour of the enclosed space, so different from the general ground- colour. In the same figure (d) I have given a row of rosettes taken from the flank of a Leopard skin, disposed diagonally. Like the Ocelot rosettes, they might readily coalesce into stripes. Indeed, there are many Tiger skins (Fig. 24) which have their stripes in pairs ; and many brindled Dogs have similar markings. These may have resulted from such a disposition of rosettes as that here shown. I have seen several Leopard skins with their flank rosettes disposed in slanting rows (Fig. 15, a). To understand the transformation of the Ocelot rosettes, we should bear in mind that the Jaguar rosettes are made up typically of a polygonal ring of spots enclosing a space which is of a darker colour than the zV/ter-rosette spaces, and that the enclosed space contains some minute black specks. We find all these elements in the Ocelot markings, only they are differently arranged.1 Reference to the Ocelot figure on p. 417 of the Royal Nat. Hist. will make the transformation of the Jaguar rosettes into Ocelot bands quite clear. In this figure the lower row of flank marks is made up of distinct rosettes composed of distinct spots, like those of some variations of the Jaguar. The next row above it is largely made up of fused rosettes, and the row above that again is one long band of fused rosettes, the rings becoming the black border of the band, and the central spots becoming a row of small spots in the middle of the band. The rest of the body is covered with patches of fused rosettes. The Ocelot is essentially a South American species, and like its close relative, the Jaguar, is said to be an expert climber. From the markings of the ocelot the transition is easy to those See Stuffed Animals, Natural History Museum — case containing Ocelots. SPOTTED AND STRIPED MAMMALS 35 of the Marbled Cat (F. marmoratd], and those of the Clouded Leopard (F; nebulosa), both of which can be seen on pp. 409 and 407 of the Roy. Nat. Hist. Besides the two variations of Ocelot which I have given, there are others which have longitudinal stripes that do not enclose any spaces, and are not unlike those on the shoulder of the light- coloured Ocelot in the foregoing figure (19). . There is a large number of spotted animals, and in the Appen- dix I have given as many as I could. The point the reader should note is that the rosettes of these spotted animals become dark rings on the tail, alternating with rings of the general ground-colour. Having studied these resetted Cats, we are now in a position to understand their relation to striped Cats. There are numbers of small Cats and Genets with their spots arranged in longitudinal order, and others, as may be seen in Fig. 27, with them arranged in transverse order. This happens frequently, not only in the Cat tribe, but in other animals also, as may be seen in Appendix A, Nos. 16, 17, 18, and others. I have said that it will not be difficult to show that the striped animal is only a modification of the spotted one. I have already shown that in the Ocelot spots run into longitu- dinal stripes and bands. Now I shall endeavour to show that the stripes of the Tiger are no other than the fusion of transverse strings of spots, so transformed as to have lost all semblance of their spot origin. The striped animals par excellence are the Zebras and Tigers,1 with the minor Tiger Cats. With the Zebras I shall deal in an- other place. Animal Kingdom of Baron Cuvier, Mr. Edw. Griffith, in vol. ii. p. 444, gives a pure white Tiger, with only a shading of stripes. STUDIES IN THE EVOLUTION OF ANIMALS Fig. 21 is the picture of a living Tiger, and Figs. 22 and 23 are the pictures of two very differently marked Tiger skins. It will be noted that on all three there are some spots which have not coalesced into stripes. A glance at the spots of the living Cheetah and of the Cheetah skin (Figs. 10 and u) will show that in many places they are arranged in transverse rows, viz., on the flanks and on the fore-legs ; the Leopard spots on the fore-legs are also arranged in rows. A ««•*,- FIG. 21. — Picture of a living Tiger, from a photograph by Ottomar Anechiitz. very little change will make the spots closer, and a further change will first amalgamate them into beady strings l and then turn them into bands, as we have seen occur in the Ocelots ; only in the Tiger and certain Cats the bands are transverse and their margins are sharp, while in the Ocelot they are longitudinal and their margins are scolloped. It is very strange that spots in certain animals, and in certain 1 In a previous note I mentioned having seen Cheetah spots run into beaded strings. SPOTTED AND STRIPED MAMMALS 37 parts of the same animal, very frequently show a tendency to arrange themselves in either longitudinal or transverse orders, and often coalesce into stripes. When irregularly disposed rosettes FIG. 22.— Tiger skin, from a photograph by Messrs. Dixon and Son. Skin lent by Messrs. Jeffs and Harris. coalesce, they form the large patches of the Clouded Tiger (F. diardi) of Elliot's monograph. What is still stranger is that the black rings of the rosettes FIG. 23. — Tiger skin, from a photograph by Messrs. Dixon and Son. Skin lent by Messrs. Jeffs and Harris. SPOTTEt) AND STRIPED MAMMALS 3$ coalesce with other black rings, and form a larger ring or band outside the amalgamation, and the brownish enclosed spaces FIG. 24. — Tiger skin showing twin stripes. Photograph obtained from Messrs. Russ and Winckler, of Edinburgh. coalesce and remain inside the patch or band, as in the Clouded Tiger and in the Ocelot. 40 STUDIES IN THE EVOLUTION OF ANIMALS Fig. 25 shows various degrees of transformation of spots into stripes and blotches on the legs of certain carnivora. On the other hand, we should not forget to note that on the legs of striped FIG. 25.— a and b, fore- and hind-feet of a tiger ; c and d, fore-feet of two different leopards ; e and/, fore-feet of two different lynxes. From Coloration of Animals and Plants, by Alfred Tylor. animals sometimes all markings disappear. In the window of a furrier I have seen a young tiger with plentiful stripes on its hind- quarters and almost none on its shoulders and fore-legs ; and we know also that the Ouagga (Fig. 54) is plentifully striped on its front parts and has no stripes at all on its haunches and hind-legs. SPOTTED AND STRIPED MAMMALS I have seen a Leopard skin with crowded rosettes, several of which were fused into one oblong ocellus, as shown in Fig. 15, b. This fusion will afford some idea of how the parallel twin stripes of the Tiger skin of Fig. 24 may have originated. Fig. 26 gives a diagrammatic sketch of some spindle-shaped ocelli I saw on a Tiger skin. A row of Leopard rosettes, as shown in Fig. 20, d, may easily be transformed into a pair of twin and parallel transverse stripes. £Z/ FIG. 26. — Spindle-shaped ocelli on a Tiger skin; a — 3 represents the spinal line. We have already seen that similar twin bands do actually occur in the Ocelots from rosettes disposed longitudinally. The reader should especially note that in the figure of the living Cheetah the spots on the tail have gradually coalesced, and formed continuous rings towards the tip. These ringed tails occur whether the animal be spotted or striped, and in the figure of the living Tiger the rings on the tail are double, indicating their origin from rosettes ; and indeed in Fig. 24 almost all the stripes on the body are double. This may be considered conclusive evidence that the stripes of all Tigers, however modified they may be, 42 STUDIES IN THE EVOLUTION OF ANIMALS originated from rows of Leopard rosettes. We may note further that in the Jaguar skin (Fig. 4) the spots on the chest have FIG. 27. — Markings of different small Cats, from a photograph by Messrs. Dixon and Co. Skins lent by Messrs. Back and Co. coalesced into beady stripes, and we know that the separate ring- spotlets of the Jaguar rosettes in other Leopards, do coalesce into a continuous polygonal ring. SPOTTED AND STRIPED MAMMALS Then in Fig. 27 we have a striking series of transitions in the smaller Cats from spots to stripes. Some specimens show only spots on the flanks ; others, spots coalesced into wavy or beady stripes; and others show more finished stripes, like those of Fig. 28. In the British Museum enclosure there is a Domestic Cat which I often stop to look at. The posterior half of its body is spotted ; the anterior half is striped transversely ; the neck and head are striped longitudinally ; the legs are striped transversely, and also spotted. Then along its spine it has a broad black band, and its tail is ringed in its terminal half. Here we have a sort of general- ised marking, combining a little of each of the special features of distinct races of animals, the black band along the spine in some animals being possibly the only vestige of ancestral spotting ; while the ringed tail in the Racoon is the only vestige left to tell the tale of its ancestral markings. In the International Fur Stores I saw the skin of a Tiger which had a large ocellus towards the ventral region. This same skin had a modification of stripes on the lumbar region, as if the pigment were undecided whether it would run into separate stripes or form an ocellus. Then in another Tiger skin I saw on one side a curious rosette, and on the other a pair of parallel stripes. Both these abnormalities in the Tiger markings are given in Fig. 29 (No. i). They are not only curious, but very suggestive. FIG. 28. — Striped Cat, from a photograph by Messrs. Dixori and Son. Near the root of the tail it has a few rosettes. 44 STUDIES IN THE EVOLUTION OF ANIMALS If one had the opportunity of examining hundreds of skins of Leopards, Cheetahs, Tigers, and Cats, I have no doubt whatever that a perfect series might be picked out which would easily prove the transition from spots to stripes. The examples which I have given, I think, are sufficient to convince any one of the relationship of stripes to spots and rosettes. A word about the tadpole-shaped ocelli on both sides of the No. i. m JL.J mzggzP No. 2. FIG. 29, No. !.—(«) Large ocellus near ventral region of Tiger skin ; (b) combination of a curious ocellus and a pair of stripes ; (c] the spinal line. No. 2. — (at b, and c] Transitions from simple stripes to ocellated stripes of the Tiger, as seen in Figs. 22 and 23. a> Tiger skin of Fig. 23. I do not think that these are enlarged and spindle-shaped Leopard rosettes, although in Fig. 59, No. 5, I have given one which has turned into a beaked ocellus. I think that the Tiger marks in question have a different origin. Tiger stripes are sometimes parallel throughout their whole length, as seen in Fig. 24 ; but at other times the stripes are shifted so as to make one commence about the middle of the other, as in the lumbar region of Fig. 21. By approximation and partial fusion, two stripes thus shifted would make a spindle- SPOTTED AND STRIPED MAMMALS 45 shaped figure, with an ocellus in the middle ; if the ocellus were closer to one end, the figure would become not unlike the outline of a tadpole, like those on the Tiger skin of Fig. 23. No. 2, Fig. 29, is a diagram intended to show the transforma- tion from simple stripes to spindle-shaped ocelli. I think I have said enough (and perhaps more than enough) regarding the striping of Tigers to show that it is simply an extreme modification of the Jaguar and Leopard rosettes. But if the reader should have any doubts about the descent of stripes from spots, a glance at the small Cat skins of Fig. 27 ought to convince him that the view I have taken of the genesis of stripes, in the Cat tribe at least, is in all probability the right one. We see separate spots passing into beady stripes and finally into Tiger stripes on the hind-legs. On the shoulders of the small Cats the striping is so fine that it is rather a brindling. Then in the Natural History Museum, among the Cat family, there are numerous specimens which show simple spots, mixtures of spots and stripes, and simple stripes either transverse or longitudinal, and also transitions from the one kind of marking to the other. I might have dispensed with such a multiplicity of facts in support of what I said ; but to the general reader, who may not be in the habit of seeing at a glance the obviousness of a con- clusion, they may be useful in bringing home to him the truth that stripes are evolved f rout rosettes. If now we turn to other animals, such as the Deer and the Antelope, we shall find that spots and stripes are interchangeable and intermixable. Fig. 30 shows the spotted young one of a Deer in the Zoological Gardens ; the adult showing no spots whatever.1 1 In the Edinburgh Museum of Science and Art there is a good specimen of a young spotted Wapiti ( Cervus Canadensis). 46 Then if the reader will turn to the Review of Reviews of March I5> *893, where a character-sketch of the great African hunter, Mr. F. C. Selous, is given, he will find on p. 258 a Kudu Bull beautifully striped, with no spots, and on 'p. 260 an allied Antelope, the Bushbuck of the river Chobe, which is striped and also spotted. Of the latter a fine illustration is given in FIG. 30. — Shows the young of a Deer covered with spots, while the adult has none; taken from a photograph, Zoological Society's Gardens. the Roy. Nat. Hist., vol. ii. p. 277. See also Appendix A, Nos. 20, 21, 22, 23, and 25, of this book. The changes from spotting to nothing in the same individual, and from spotting to striping, or a mixture of both, in the same genus of Antelopes, is very remarkable. For some reason the spotting of the adult of Axis maculatus, shown in Fig. 14, is not obliterated, although in the Deer of Fig. 30 no sign of spotting remains in the adult. SPOTTED AND STRIPED MAMMALS 47 It will, however, be preferable to let Mr. F. C. Selous1 speak upon the question of spotting and striping in the Antelopes of Africa. It would appear that not only age, but the climate and food of a locality, may have a good deal to do with the changes in the markings of the skin. Of the Bushbuck ( Tragelaphus sylvaticus, Sparrm.) he says : * In the Cape Colony, the adult male is deep dark brownish-black, with two or three small white spots On the haunch, and one pr two on the shoulder ; the adult female is light reddish-brown, with white spots on the haunches, and sometimes a feW between the shoulders and flank ; the young males are reddish-brown, and more or less spotted. 1 On the Limpopo, however,: the adult males are £>r6wnish-grey, often without a sign of any spots ; and the young females are more spotted than old ones. The \adult females are of a dark red, with a few white spots; the young males" are a good deal spotted, with a few transverse stripes. 'On the tributaries of the Zambesi, east of the Victoria' Falls, the male Bushbucks are of the same colour as the young males found on the Limpopo, being dark red thickly spotted oil the haunches, shoulders, and sides, with small white spots, and with three or four faint white stripes down each side. The adult female is pale yellowish red, beautifully spotted, and with a few white stripes.' Then of the Bushbucks on the Chobe Mr. Selous says : ' The .adult males are of a very dark red colour, most beautifully spotted with large white spots, as many as fifty on each side in some Individuals, and in some cases as many as eight well-defined .stripes. In addition, they have a mane of white hair three inches long, from shoulder to tail, which can be erected. Young 1 A Hunter's Wanderings in Africa, p. 209. 48 STUDIES IN THE EVOLUTION OF ANIMALS males are of a pale red-yellow, with spots and stripes much more faintly marked than in the adult animal. The adult female is of a rich dark red, beautifully spotted with white, and with three or four faint white stripes on each side, and a dark spinal line. The young female is of a lighter red, and not so much spotted. In Cape Colony and on the Limpopo, young Bushbucks are more spotted than adults ; they gradually lose their markings as they become older; while on the Chobe and on the tributaries of the Zambesi this order of things is reversed. Adult animals are far more beautifully marked than young ones.' Then of Tragelaphus 6/te/£zV (Sclater) he says : ' A foetus had the skin striped and spotted yellowish-white, as in the adult Bushbuck of the Chobe. Another recently born had a lighter colour, and fainter spots and stripes ; the adult is of a uniform greyish-brown without either spots or stripes.' From all this it would appear that the spotting and striping of the Bushbucks does not depend on either age or sex, and that the individuals of this genus differ much in marking and colouring ; but, although differing so much as to become almost distinct species, physiologically they remained one species ; and, living together in the African bush, they must have crossed and have become mixed up, so that the life-history of one individual seems somehow to give successive photographs, as it were, of the life- history of the race. Anything more bewildering than the facts placed before the reader by this hunter-naturalist of Africa cannot well be imagined. It is impossible to read Mr. Selous' book and not feel convinced that these Antelopes, when living for months in waterless tracts, are at the mercy of their surroundings, not only for their life, but also for the physiology of their skins. For at p. 207 he says that in some parts of the country, for several months in the year, SPOTTED AND STRIPED MAMMALS 49 there is absolutely no water, and Elands, in common with Gems- buck and Giraffe, live and thrive there, and appear to do better than in well-watered parts of the country. He thinks that in the dry seasons these desert animals get the necessary amount of water by eating a watery melon, which is plentiful, and a white watery bulb, looking much like a turnip. Among Antelopes, we have the head of a Kudii with three white spots on its cheek.1 Then in Appendix A, No. 27, is shown one solitary broad stripe on the hind-quarters of the Waterbuck. These, like the ring-tails of many animals, I take to be simply vestiges of more extensive ancestral spotting and striping. Indeed, climate, food, and age may have a great deal to do with the retention or disappearance of spots and stripes. We see that in the Deer of Fig. 30 the spots wholly disappear with age, while in these two Antelopes all spots and stripes disappear, excepting, maybe, three cheek spots in the one and one haunch stripe in the other. Mr. Selous says : ' In the Mashura country every Eland cow is plainly striped. One had nine broad white 2 stripes on each side. Elands that are much striped have a whitish mark across the nose, like the Kudu. Old bulls have no stripes. Great variations occur in this respect.' Again turning to Dogs, we find that spotting and striping are found among them also. Fig. 3 1 shows a distinctly spotted Dog.3 Whether the Dog got 1 Shown in Mr. Selous' book, in vol. ii. figs. I and 2. 2 It should be noted that in certain mammals, such as the Tiger and Zebra, the stripes are black : while in these Antelopes the stripes are white. Both spots and stripes are liable to change from black to white, or vice versd ; that is, white becomes melanoid, and black becomes albinoid. 3 In the Natural History Museum there is a Phalanger — a marsupial — spotted much in a similar manner. In the Encyclop. Brit, the picture of a flying Phalanger is given with transverse stripes on its back. In Somerset I saw a sucking Pig which was spotted almost like some Dalmatian Dogs, but the spots were larger. D 50 STUDIES IN THE EVOLUTION OF ANIMALS this spotting from some mammal allied to the Cheetah, or not, I do not know. Canine and feline animals are rather closely allied. Moreover, both the Cheetah and the Dog want the retractile claws of the Cats proper.1 FIG. 31. — Dalmatian Dog, from a photograph by C. R. , 54. Fig. 32 shows the Dog-spots fused into blotches not unlike the consolidated rosettes on the abdomen of Leopards. In the Science and Art Museum of Edinburgh there is a large Boarhound with the Dalmatian spotting agglomerated into even larger blotches. 1 Among Hyosnas there are species which are distinctly spotted, and others distinctly striped ; although in Hyoenas the claws are well developed, they are non-retractile. SPOTTED AND STRIPED MAMMALS Probably this is only a preliminary step to piebalding, which is so common in Dogs. It is conceivable that if this attraction of black spots for each other increased, we should soon get the piebald colouring of the Fox-terrier and other breeds. At Worthing I saw a curious hybrid between a Bloodhound and a Dalmatian Dog — at least, its owner so stated. Its legs were white with well-defined tan spots ; its back and flanks were white and thickly spotted with black ; and those on the flanks were grouped in threes and fours, not unlike the consoli- dated rosettes on the abdomen of the Jaguar and Leopard ; while its head was white, spotted with tan. It showed a curious persistence of spot- ting ; but where the tan colour of the Bloodhound came in, the spotting of this Dalmatian hybrid became tan-coloured ! Then in the streets of London I saw another Dog of the Dalmatian breed. A large number of the dorsal spots amalgamated into a large black patch ; half its face was spotted as usual, and the other half wholly black. On another occasion I met two Dogs of this same breed, pro- bably brothers. One was almost wholly black, with some re- maining white inter-spots, and half its tail was spotted with black ; FIG. 32. — Blotched Danish Boarhound, from a photograph by Messrs. Dixon and Son. 52 STUDIES IN THE EVOLUTION OF ANIMALS while its companion had the black spots quite close to each other, though much more distinct. Then in Hyde Park one day I saw a curious Toy- terrier. It was of the black-and-tan, short-haired breed ; but the parts that are usually wholly black, -in this case were grey, blotched and striped FIG. 33. — Brindled Dog, from a photograph by C. R., 847. with black. It was not unlike the black-backed Jackal of the Zoological Gardens. Fig. 33 is that of a Brindled Dog. Here the stripes are unlike those of the Tiger — that is, not so decided, but more like the brindling on the shoulders of the small Cats in Fig. 27. The stripes of the Dog are much finer and dissociated ; but in the streets I have SPOTTED AND STRIPED MAMMALS 53 seen brindled Bull-terriers which had closer and broader stripes, with some which were broken up into fine lines ; and in some cases many of the stripes were distinctly in pairs, suggesting some origin similar to those on the Tiger skin of Fig. 24, and presumably there- fore the twin stripes in the Dog must have been caused by a similar modification of rosettes. Mr. Rawdon B. Lee, in his book on Modern {Sporting} Dogs, gives a good figure of a Danish Boarhound with conspicuous stripes. In brindled Dogs we have to note that the stripes on the limbs follow the direction of the limbs, and are not transverse to them, as in Cats, Zebras, and striped Hyenas. In some Tigers I have seen a tendency to a similar disposition of the limb stripes. This, how- ever, need not embarrass us, as we have already seen that, in the Cats, spots may group themselves into stripes either longitudinally, or transversely, or diagonally. Brindled Dogs are to be found in various races — in Greyhounds, Boarhounds, Bulldogs, etc. In the Viverridce there is presented a similar study. We see large spots breaking up into numerous small ones, or perhaps the reverse 1 — that is, small ones agglomerating into large ones ; also spots stringing themselves into stripes, longitudinally on the body, and transversely on the legs. In several species of the Mungoose a complete intermixture of pigments seems to have occurred, so as to produce a sort of grizzly- grey coat ; while in the Zebra-Mungoose and in the banded Mun- goose, both of East Africa, the spots have arranged themselves in stripes and bands transversely (see App. A, No. 15). In Galidea, however, we see a wholly brown surface, with a few black rings on the tail, as a vestige of ancestral striping or spotting. What we have to note very particularly is that the Indian Civet 1 See Appendix A, Nos. 9 to 12. 54 STUDIES IN THE EVOLUTION OF ANIMALS ( Viverra zibetha) in the Science and Art Museum of Edinburgh has Leopard rosettes on its haunches, simple spots on its shoulders, and marblings on its flanks ! and that the Spanish Lynx (Felis pardina, Oken) has Leopard rosettes on its haunches, and simple spots over the rest of its body. After having passed in review so many spotted and striped mammals, we may perhaps be in a position to divide their markings into — (a) Spots and groups of spots forming rosettes, or solid blotches. (b) Stripes or bands of various breadth, either transverse, diagonal, or longitudinal. (c) Marbled or clouded markings, like those of some Cats. (d) Piebald markings, like those of Dogs, Cattle, Horses, etc. And finally we have (e) Self-coloured animals, which present a total obliteration of spotting and striping. These may be subdivided into pure selfs, without a speck of any other colour; selfs with vestiges of spotting ; selfs with ringed tails ; and selfs with points of other colours, such as we see in Horses, Dogs, etc. The dun-coloured Cat, with black points, is a very interesting variation. It is seen in exhibitions. From the study of all the foregoing, I have come to the con- clusion that each ancestral rosette, originally composed of a ring of isolated spots, has in time undergone the following marked modifications, some of which are found in the same animal, and others in distinct individuals :— (a) The isolated spots have fused into continuous rings, or segments of rings, as in many Leopards. (£) The ring has contracted into a large spot, with obliteration of the enclosed space, as in the Serval and others. SPOTTED AND STRIPED MAMMALS 55 (V) The rosettes, sometimes many of them, have fused either into large bands or patches, as in the Ocelot and marbled Cat. (d) The consolidated spots, after arranging themselves into rows, either transversely, diagonally, or longitudinally, have fused themselves further into stripes, as in the Tiger, the c Tabby Cat,' the Pampas Cat, and certain Civets. (e) The rings on the tail have followed the same course of modification ; the consolidated spots have fused into rings, or the rosettes have fused into twin rings, as in the Margay ; these, in some descendants, have then amalgamated into broad bands. (/) Finally, the resetting, spotting, or striping has been entirely obliterated from the adults of certain species, such as the Lion, the Puma, the Caracal, jet-black and albino Cats, and others, while in the young of some the spotting remains distinct.1 The rusty- spotted Cat 'is quite peculiar among spotted Cats in having the tail without either spots or rings ;' while in some mammals, as in the Racoon and the cunning Bassaris, the only vestiges of ancestral spotting or striping are the * rings on the tail.' 1 Young Lion cubs are usually spotted ; but Mr. Edward Griffith, in The Animal Kingdom of Baron Cuvier, vol. ii. p. 447, gives two Lion-Tiger cubs, three months old, striped like Tigers. AND SOME OTHER MAMMALS ' The first master strikes out a luminous idea, and writes a great book which promises speedy results ; but after his own generation has been dazzled by it, comes the criticism of the next : exceptions, and violations of his laws, are discovered ; the large views.which he stated with convincing clearness become misty and obscure ; and men set themselves to rediscover, in some new way, generally with poor and shabby minuteness, and with many modifications, what was once an accepted theory.' The Present Position of Egyptology, by Professor MAHAFFY, Nineteenth Century, Aug. 1894, p. 269. PART II DAPPLED AND STRIPED HORSES AND SOME OTHER MAMMALS FOR my purpose, under the term Horse I include all animals that come under the denomination of the genus Equus. In the Leopards and Tigers it was easy to show the derivation of stripes from spots or rosettes. There is, however, a domestic animal which is differently marked from Leopards. I mean the dappled grey Horse shown in Fig. 34. He has a congener — the Zebra — in which the stripes are quite phenomenal. In these animals it is not so easy to trace the striping from spotting, although, I think, it can be done. There are three distinct varieties of fully dappled Horses like that shown in Fig. 34, viz., the white Horse reticulated with grey, the dun Horse reticulated with black, and the brown Horse also reticulated with black.1 The markings of the dun or sponge- coloured Horse are very striking. They are all called dappled Horses in the trade — grey, dun, brown. I have called the darker pigment reticulation, because it appears as if a net were thrown over the fully dappled Horse, leaving the meshes filled with either white, dun, or brown. The dappling or spotting of the domestic Horse is so persistent, 1 Not improbably the dun and the brown dappled Horses are melanoid variations of the grey dappled Horse. SL c 15 XJ c o o "a rt bJO T3 ^OJ n O. c3 Q DAPPLED AND STRIPED HORSES 61 that we see it, more or less, going through all the changing colours of Horses ; and it would be almost as hopeless to give distinct names to all the variations of colour in Horses, as it would be to name all the shades of colour in domestic Pigeons. The very fact that the dappling is so persistently inherited, either wholly or vestigially, would indicate that it comes from the very foundations of Horse evolution. I have not been able to dis- cover that any existing species of the genus Equus, in the wild state, is dappled. The earliest record of a dappled Horse, in a state of domestication, that I can find is taken from a Spanish MS. of the eleventh cen- tury. The quaintness of its mark- ing is shown in Fig. 35, and the author thinks it was of the Arabian breed. The markings are most conspicuous in the grey dappled Horse, because the colours are in black and white ; but the dappling is traceable in the bay, the chestnut, the brown, the black, the roan, the cream, the dun, etc. etc. The pure white, the pure black, and other pure self- coloured Horses may be free from traces of dappling ; but the vast majority of Horses are either fully dappled, or have traces of dappling, and these are most persistent on the hind-quarters, round the root of the tail. The Horses of the '2nd Life Guards are either black or nearly so. I noticed that those which took FlG. 35. — Spanish Horse, from Horses of Antiquity, by Ph. Ch. Berjean (p. 23, MS. xi. Cent.). 62 part in the escort at the opening of the Imperial Institute were almost all dappled on the hind-quarters, round the root of the tail. In dun l or sponge-coloured Horses, the dappling in this par- ticular region is often amalgamated into a sooty-black patch on FIG. 36. — Dappled grey Cart-horse, from a photograph by Mr. Stanborough, of Bexhill- on-the-Sea. each side of the tail-root ; a similar sootiness results from the fusion of dappling along the upper ridge of the neck. Some grey Horses are very distinctly and strongly dappled, such as those given in Figs. 34 and 36. I think it very beautiful 1 Mr. Darwin defines dun as ranging from ' between brown and black to a close approach to cream-colour' (Origin of Species, 1888, p. 200). DAPPLED AND STRIPED HORSES 63 to see a pair of finely shaped grey carriage- Horses prettily spotted. Should any of them die, their skins would make pretty rugs. Unfortunately, for some reason, spotted Horses are not fashionable, and do not appear to be kept for breeding purposes. In some instances the dark reticulations are all over the body, but more conspicuous on the flanks, the dappling on other parts being often modified. The white dapples of the grey Horse can be seen to vary from irregular patches to small spots. In some regions, such as on the fore- and hind-legs of Fig. 36, the smaller dapples seem to have amalgamated into large fern-like patches. In other cases, such as those on the fore-leg of Fig. 34, the dapples have degenerated into star-shaped marks, which often dwindle into minute specks like those on the flank of Fig. 39, all the rest of the ground being of a dark grey, and in some cases almost black. Indeed, we might say that the two extremes of the grey dappled Horse series were — (a) a white Horse with traces of grey reticulations, and (b) a blackish horse with traces of white spots. In other words, the grey reticulations that isolate the white dapples of the grey Horse can be obliterated, either wholly or partially, and the Horse made either wholly white, or white with vestiges of dappling. On the contrary, the white dappling may be obliterated, and the Horse made either wholly dark grey or dark grey with vestiges of white spotting. The star-marks on the fore-legs of Fig. 34 should be compared with those of Fig. 36. The invasion of the white dapplings by the grey reticulations is partially seen in Fig. 37. Few, I venture to say, have any notion how much may be learnt from Horses of all sorts which are to be seen by thousands in the streets of the Metropolis. They are ready-made experiments for scientists to take up and theorise about. Unless pure white, 64 STUDIES IN THE EVOLUTION OF ANIMALS chestnut, or flea-bitten, there is scarcely a Horse which does not bear vestiges, more or less pronounced, of dappling. In Fig. 38 is given a spotted Horse, which shows the dappling on the flank disposed in slanting rows ; and Fig. 34 shows that on the neck the dark colour tends to form bands. FIG. 37. — Grey dappled Pony, from a photograph by C. R., 922. Note that on the groin of both Horses of Fig. 38 the dapples are being broken up into minute specks. When this occurs all over the surface, it probably gives rise to what is called a ' flea-bitten ' Horse, with either black or brown specks. DAPPLED AND STRIPED HORSES 65 I would ask the reader to note particularly the rows of slanting dapples on the flank of the upper Horse of Fig. 38. I have already referred to similar slanting rows of rosettes in certain Leopard skins (Fig. 15, a), and shall have to refer to them again. No one, I think, will doubt that these spots in this Horse are vestiges of the larger dapples, like those of Fig. 34. If a full-blown dapple or rosette can be reduced to a mere point, as we see it in certain Horses and other animals, it stands to reason that it can be much modified otherwise. We do not know what atomic conditions of the nerve-centres are requisite to produce this minute specking, but it is evident that a more complete intermingling of the pigmented hairs with the white ones would give rise to a roan or a strawberry roan. On the other hand, when the pigments agglomerate in separate large patches, we get the same piebald conditions seen in Cattle, Dogs, Pigs, etc. I am not here going to enter into the intricate question of how the dappling of the young Horse commences — whether by minute spotting becoming larger, or by large patching dwindling eventually into minute spotting. It is a difficult question to unravel, and there does not seem to be any accurate information on this point. As to how the dappled Horse originally came into being at all, there would not seem at first any means of finding out. Fossils in no way record the coloration and markings of the skins of extinct animals. Nevertheless, I hope to throw some light on this point of evolution later on. The existing wild congeners of the Horse are either striped, like the Zebra, or self-coloured, like the Kiangor wild Ass. The coloration of the latter is a sort of tan or fawn colour, while in the domestic Ass mouse-grey is a common colour. The person who originally invented the names for the colours of Horses must have been colour-blind, for how could he have called E FIG. 38. — Two Cart-horses, from photographs by Mr. P. D. Coghill of the Royal Veterinary College, taken by kind permission of Mr. J. Poynter, Horse Department, Great Northern Railway Company. DAPPLED AND STRIPED HORSES 67 ' chestnut ' the colour of a Horse, which, if it were a Cow, would be ' red.' And to call a Horse tan-coloured would be simple heresy. Nevertheless, what is called a golden-bay is nothing but a rich tan- colour, which in other individuals shades off into the dun, the sponge- colour, the cream, and the white ; while in another direction this tan shades off into the chestnut, the bay, the brown, and the black. All the experts whom I have consulted agree in saying that the Horse, when recently foaled, is never dappled, but is of a uniform dark colour, excepting albinos. I asked a farmer who is a great hunter, and who has also bred Horses, and has had ample opportunities of seeing young foals, whether he had ever seen a recently born foal which was dappled. He replied — not one. I am informed that the dappling, when it does come, begins to appear when the foal is a few years old. This is rather curious, for in the case of some Deer, as shown in Fig. 30, the young one is plentifully spotted, while the adult has no sign of spotting.1 No one seems to have made any accurate observations on the dappling of the Horse — when it commences, how it commences, and how it proceeds, although there are many records of Zebra-striping in the Horse. Among the thousands of Horses in the streets of London, one sees all possible variations of dappling — from a few spots to the whole body covered with maculations. Does the same individual go through all these phases of dappling, or are certain variations permanent? Does dappling commence gradually and go on to its maximum extent, and then gradually disappear, or how ? A veterinary surgeon told me that the dappling varies with every change of coat of the Horse ; and all seem to agree that as the Horse grows older the white colour increases and the dark colour 1 In the Natural History Museum there is a very young Jaguar which is wholly brown without any spotting. 68 STUDIES IN THE EVOLUTION OF ANIMALS diminishes. The chafing of the collar seems to have the same effect ; but in Fig. 39 and many others the reverse seems to have occurred. Does sex make any difference in the dappling? A FIG. 39. — Omnibus Horse with the spots becoming obliterated, leaving a dark-grey surface ; from a photograph by Gabrielli, taken by permission of Mr. Duff, manager of the London Road Car Company. great deal is known about the powers of running of the Horse, about his powers of draught, about his anatomy, his physiology, his pedigree, and perhaps about his descent and relation to extinct and living animals ; but very little seems to be known about the origin and course of his dappling. DAPPLED AND STRIPED HORSES 69 What is wanted is that some amateur with leisure and means should undertake to photograph the dappling of the same Horse as soon as this feature commences, and to photograph the same Horse on both sides every year, after the Horse's change of coat. So many leisured persons possess cameras, that this bit of work ought to be an easy amusement If many were to undertake this work, so much the better. And if the Horse were closely clipped after being photographed, and then re-photographed, we might be able to discover how far the pigmentation of the skin coincides with the dappling of the hair.1 We would then have some accurate data to build theories upon ; and by comparing the dappling year by year, we might have the revelation of some interesting facts. All these seem trivial things, but from an evolutionary point of view they may be important. However trivial a fact may appear at one time, it may one day turn out of value. This any one can see for himself, viz., that the colour of the clipped Horse is much lighter than it is before clipping. Part of the darkness of the old coat may perhaps be put down to dirt, and part to the action of light and weathering. In some cases, after clipping, the surface shows traces of dappling which it did not show before ; and in roan Horses the clipped surface is often darker, or lighter. We seem to have more definite information about crustaceans, fished out of the ocean from a depth of 3000 fathoms, than we have of the changes in the colouring and marking of the Horse, an animal which has been in daily use, in various ways, for thousands of years ! 1 I saw a pink-white Horse in an omnibus. It had very little hair — indeed, it was almost hairless ; and on its shoulder it had dark pigment-marks in the skin, like those of the hair-marks on a grey dappled Horse. Moreover, it had dark circular spots in many parts of the skin, like those of the Dalmatian Dog, the rest of the skin being of a blush-rose colour. 70 STUDIES IN THE EVOLUTION OF ANIMALS Considering the millions of Horses that are bred everywhere, both in a domesticated and also in a semi-wild state, it is astonish- ing how little reliable information there is on this particular subject. As I said, from an evolutionary point of view this study would be important, as" the history of dappling in any individual ought to tell some tale regarding descent. In absence of any recorded accurate information, I have had to explore the Horses in the streets of London and elsewhere, in the immense stables of carrying companies, in Horse-shows, etc. Wherever I could see any deviation which I considered of some importance, I made a note of it on the spot. Have you ever observed a ' dappled sky ' ? The maculations of some dappled Horses, such as those of Fig. 37, are not unlike the patches of cumulus clouds with jagged edges, as they are often seen close to each other in a ' dappled ' sky, the intervening blue sky corresponding with the network of dark grey between the Horse-dapplings. Just as clouds are unstable, break up, and run into each other, forming a uniform dense haze, so do the jag-margined Horse-dapplings seem to change with age and from other causes. The cloud-patches of the Horse often break up and deliquesce — to continue the simile — as seen on the hind-quarters of Figs. 34 and 39. This I found, and have confirmed it hundreds of times in omnibus Horses. After severe exertion in drawing a loaded omnibus, the superficial veins of the flanks, shoulders, and legs start out. On the flanks they form reticulations which, in dappled or partially dappled Horses, coincide with the dark reticulations. In self-coloured Horses, such as pure whites, pure bays, etc., only the venous reticulations are seen. But whenever there is a fine pig- mentary reticulation of a different colour from the general colour, the two reticulations coincide — the venous and the pigmentary. In freshly clipped Horses all this can be seen very plainly. DAPPLED AND STRIPED HORSES 71 In another place I have endeavoured to account for this coincidence. In Fig. 40 (No. i) I have given a diagram of what might be a portion of the flank veins of a Horse ; and in No. 2 I have shown the same pigmentary reticulations broadened by invasion of the dark pigment, or, what comes to the same thing, by contraction of the white patches. The broad reticulations still correspond with the venous network, shown by dotted lines, which lies in the No. i. No. 2. ^ FIG. 40. — Diagrams of reticulations of flanks of Horses. No. i. (a) white patches ; (b) dark reticulations, coinciding with veins. No. 2. (a] contracted white patches ; (b} superficial veins. middle of the channels between the dapples, and therefore are not so conspicuously coincident with the network. When, however, the pigmentary network is fine, it lies over and perfectly coincides with the venous network on the Horse's flank. If you observe a dark-grey Horse and a white-grey Horse, you will see that in the former the white spots are disappearing, and mingling more and more with the dark-grey of the ground-colour, to form a uniform grizzly-grey colour, as in the upper Horse of Fig. 38 ; while in the latter the dark reticulations are lessening more and more, and restricted to mere vestiges, mainly on the STUDIES IN THE EVOLUTION OF ANIMALS shoulder and haunch, as in the lower Horse of the same figure. In many cases the white-grey Horse has nothing but the reticulations of the superficial veins to mark the places of former pigment reticulations, these having wholly disappeared, and having been replaced by a uniform white colour. FIG. 41. — (a] and (b] are from the right hind-legs of two different Horses; (c] is from a light-bay Cart-horse (Whit Monday Show) ; (d) is a fern-like dappling over the superficial vein of the fore-leg of a dark-brown Horse (Whit Monday Show). Certain well-dappled grey Horses have a very peculiar mark, like a fern-frond, which is pretty constant on the hind-legs, on the fleshy part between the heel and knee?- which is plainly visible in Fig. 36. This also coincides with a similarly disposed venous ramification on that particular part of the Horse's hind-leg. In the accompanying diagram (Fig. 41) are given three branching veins 1 Anatomical heel and knee are here meant, and not the veterinary terms. DAPPLED AND STRIPED HORSES 73 which correspond with this curious fern-like mark, and also a bay- coloured fern mark from the fore-leg of a brown Horse. The latter would perhaps correspond to those interesting marks on the fore- leg of Fig. 36. The fern-like mark on the hind-leg of the grey Horse, when present, is always situated in the same place, viz., on the fleshy part of the hind-leg, in front of and a little above the hock. On the legs of Horses the larger superficial veins have usually a somewhat transverse disposition, while on the flanks they are reticulate. That the superficial venous distribution of the Horse has some- thing to do with the pigmentation of its skin, I have not much doubt ; but what that ' something ' exactly is I am unable to say. Perhaps I ought to say the nerves of the veins have something to do with the pigmentation of the skin. I have ransacked all kinds of works on the Horse in search of its general superficial venation, but have not found such a thing. Indeed, Professor M'Fadyean has told me that there has been yet no such publication. The following, however, may be interesting to the student of the physiology of animal markings. Nine months after I had written out my ideas on the origin of the markings of animals, and after I had received the photographs of a dappled Horse from Mr. Stanborough, of Bexhill-on-the-Sea, I read an article in the Nineteenth Century of April 1893, by Prince Krapotkin, on ' Recent Science.' On p. 687 he writes thus : — * Franz Werner's researches upon the colouring of Snakes, recently embodied in a separate work, show that the temporary and irregular spots which appear in Fishes and Frogs under the influence of artificial irritations are of the same character, and have 74 STUDIES IN THE EVOLUTION OF ANIMALS the same origin, as the also temporary and irregular spots which appear in other Fishes, as well as in several Tritons and many Gekonides, without the interference of man. Some of the pro- voked changes of colour do not entirely vanish after the irritation is over, and they belong to the same category as the spots which appear in many animals in youth and disappear with growing age. Moreover, it is maintained that a series of slow gradations may be established between the irregular spots, the spots arranged in rays, and finally the stripes such as we see them in higher mammals like the Zebra or the Tiger ; and if these generalisations prove to be correct, we shall thus have an unbroken series from the tem- porary spots provoked by light or electricity to the permanent markings of animals.' I do not doubt that the pigments on the skins of animals are at one end of the telegraphic wires (the nerves) which connect them with the nerve-centres. Minute atomic changes, which, through age and other causes, occur in the nerve-centres, influence electrically the pigmentation of the skin ; but what we have to search for is why all this is so. This investigation I have left for another place. Let us now study a little in detail the dapplings of the grey Horse. In Fig. 36, at the joining of the shoulder and trunk, may be seen several groups, consisting of a small roundish spot surrounded by larger polygonal jag-edged spots, something like the enlarged outlines shown in Fig. 42 (a). In Fig. 38 (lower Horse) similar groups of maculations can be made out on the Horse's flank just behind the shoulder. Then in Fig. 34 there are three well-marked similar groups placed in a line slanting towards the abdomen, as well as several others. In Fig. 42 (b) I have given two Jaguar rosettes for comparison. Those of (a) and of (fr) are very similar ; but I shall show in another DAPPLED AND STRIPED HORSES 75 place that the components of these Horse dapplings are themselves only a fusion of minor rosettes — which I take to be the true homo- logues of the Jaguar rosettes. Making allowance for the evolutionary deviations which have certainly occurred during the descents of the Horse and the Jaguar from their remote ancestral common stock, I hope to show that their skin-markings also result from common ancestral markings, although those of the Horse are now much altered. But so is his skeleton altered ; and his legs, by a superficial observer, would &o • * FIG. 42. — (a) Two rosette-like groups from the shoulder of Fig. 36 ; (b] two rosette-like groups from the flank of a Jaguar, given for comparison ; (c) faint rosette-like dappling from the neck of a whitish-grey Horse. scarcely be considered as having any community of descent with those of the Jaguar. The spotting of the Horse would appear to be a transient feature, changing with age, like that of certain ruminants ; while in the Jaguar the spotting may be much more permanent, although I am not aware that anybody has made any accurate observations on the strict permanency or otherwise of the Leopard's and Jaguar's resetting. Judging from the specimens of very young Leopard's skins that I have seen, and from the very young Jaguar and Cheetah skins in the Natural History Museum, I should be inclined to say that the resetting of these animals is not strictly 7 6 STUDIES IN THE EVOLUTION OF ANIMALS permanent, although, looked at superficially, much alteration may not be noticed during the life of the same animal after reaching the adult stage. We know that in the Lion, the Puma, and various other animals the spotting alters so much, that in the adult it is on the verge of total obliteration. In the dappled Horse the spots certainly tend to coalesce into o 0° 0 C? / FIG. 43. — Various forms of rosettes seen on Horses: — (a) from flank of grey dappled Horse ; (l>) seen on both sides of a grey Horse, near the root of the tail ; (c } from a Horse of the Great Northern Railway Company ; (d and e) from dappled Horses ; (/and^) from hind- quarters of an omnibus Horse ; (h, i, and j) Horse-rosettes breaking up. frond-like patches, or to break up into star-like or other small spots, and even into minute specks, preparatory, it would seem, to total obliteration. In Fig. 43 I have given several groups of spots — rosettes, we might call them — taken from various horses, which will elucidate what I have said above. In this figure, it will be seen that in (h) the scolloped edges of the patch break up into an aggregation of a number of dots, as in DAPPLED AND STRIPED HORSES 77 (t and/). A beginning of this may be seen on the groin of Fig. 38, that is, at the junction of the haunch with the trunk. When this breaking-up of the larger dapples extends all over the skin, we get, as I said, what is called the ' flea-bitten ' horse. Now and again one sees a ' flea-bitten ' horse which, on its haunches, has ordinary dapples. This would indicate that the minute spotting is only a modification of the dappled surface, and that the ' flea- bites ' are probably the breaking-up of similar large spots. A still further and more complete mixture of the two colours 0 CXoo 0000 FIG. 44. — Diagrammatic sketches of spots from various Horses : — (a) frequent disposition of dapples on flanks of Horses (right side) ; (b) occasional triangular spotting on the flanks of Horses (right side) ; (c) rare spotting on the flank and haunch of a Horse (left side). of a dappled Horse produces the uniform roan, whether a straw- berry or an ordinary roan.1 We have now to study another feature of the dappled Horse, which is only a modification of the ordinary confused mottling, if I may so call it. As a rule, the flanks of the dappled Horse are simply reticu- lated, without any apparent order. But in certain dappled Horses the light-coloured spots on the flank occur in transverse rows, with the dark interspaces modified into broad lines or bands, both having the same slanting direction as the ribs, such as those shown in Fig. 44 (a). These rows of spots are usually squarish, 1 These roans when newly clipped are often either bay-brown or black. Their heads usually do not roan. STUDIES IN THE EVOLUTION OF ANIMALS but in one case they were triangular, and seemed to fit into each other as in (#). This disposition of the flank spots and inter- spaces can, I think, be sufficiently made out in the dark Horse of Fig. 38. Moreover, in one particular Horse which I saw in the London streets, the spots in the front part of the haunch were also disposed in rows, which met the flank rows at the abdomen, as shown in (c).1 Well, if in imagination you amalgamate all the white spots, you will have alternate light and dark transverse bands, and those of (c) would almost reproduce the haunch and flank stripes of the Zebra (Fig. 52). This is not all, for I have not infrequently seen that, in the modified dapplings of grey Horses, FIG. 45. — Rough on the upper part of the leg the white stars sketch of fore-leg of a . . dappled grey Cart- amalgamated into transverse irregular bands, horse- while the dark reticulations also amalgamated and formed alternate bands. I have shown this feature roughly in Fig. 45. It is also very partially noticeable in Fig. 38 (upper Horse). Further, on the neck of a light-bay pony at Bexhill-on-the-Sea, and also on a butcher's white pony in London, I have seen faint transverse stripes resembling those of the brindled Gnu. Then, on the upper ridge of the necks of grey dappled, and more especially brown dappled, Horses, the dark reticulations take the form of short bands. In a grey dappled Pony at the Horse Show of May 1893, the upper ridge of the neck was marked as I have 1 The striped American Marmot (Arctomys Hodii) has each of its longitudinal stripes made up of a string of white squares on a dark ground (Animal Kingdom of Ctivier, by Griffith, vol. iii. p. 186). DAPPLED AND STRIPED HORSES 79 roughly shown in Fig. 46 (a\ and the hog-mane was divided into grey and white bands, just as it is in the Zebra. Then a brown Carriage-horse, reticulated with black, had the upper ridge of the neck as shown roughly in Fig. 46 (£), each space having a spot of a lighter colour than the ground-colour. But the best example I have seen of stripes in the domestic Horse was on the 2ist January 1894, in Piccadilly, opposite b FIG. 46.— (a) Hog-mane of a grey dappled Pony, Islington Horse Show, May 1893 ; (b) markings on the neck of a dappled brown Carriage-horse. Berkeley Street. A milkman's cart had a Pony of a light- bay or dun colour. The Pony had broadish black stripes on his neck, shoulders, and flanks ; he had also faint transverse stripes above his wrists and heels. A rough sketch of him is given in Fig. 47, which I took down at the time. I have noticed that Ponies are oftener abnormally marked than larger-sized Horses. They appear to have more direct Ass and Zebra blood in them than the larger and more highly modi- fied and artificially selected Horses. Mr. Louis Robinson l suggests that the fossil Horse was about 1 North American Review ', April 1894, p. 483. 8o STUDIES IN THE EVOLUTION OF ANIMALS the size of the Shetland and Hungarian Ponies, and that these appear to be more nearly related to the original Horse, while the larger and more artificial breeds, like our breeds of Pigeons, Dogs, etc., are further removed from the original wild stock. At the Whit Monday Cart-horse Show, I saw a dark-bay Horse with brindling on part of his flank, not unlike that of a brindled Dog. FIG. 47. — Partially striped Pony of a dun colour.1 In this connection we should remember that, when the Zebra is crossed with the Ass, the striping, where it occurs, as is seen in the Natural History Museum, is not a Zebra banding, but a brindling, not unlike that of the Dog. (See Nos. 30 and 31, Appendix A.) Then in dappled omnibus Horses, along their spine, I have 1 A somewhat similar one is pictured on p. 322 of Study of Animal Life, by J. A. Thomson, referred to further on. DAPPLED AND STRIPED HORSES 81 frequently seen marks like those shown roughly in Fig. 48, which are the marks we see along the spine of many Tigers, such as that given in Fig. 22. The remarkable black dappling on the dorsal region of the white Horse given in Fig. 49 leaves little doubt that those blotches and spottings are broken-up Zebra bands. All the cases I have quoted go to show that the dappling of Horses some- times tends to dispose itself in a kind of striping or banding in some parts which is not unlike that of the Zebra. But independently of any theories of FIG. 48. — Arrow-head marks the genesis of Striping in the Horse, along the spine of some grey dappled Mr. Darwin, as a matter of fact, col- lected a large number of cases of Horses, which actually had stripes on their legs, their shoulders, and even on their faces. Mr. J. A. Thomson1 gives the figure of a Devonshire Pony, from Darwin, with bands in certain parts which are evidently vestiges of a much more extensive ancestral banding. Mr. Darwin 2 says, ' I have collected cases of leg and shoulder stripes in Horses of very different breeds in various countries from Britain to Eastern China, and from Norway in the North to the Malay Archipelago in the South. In all parts of the world, these stripes occur far oftenest in duns and Mouse-duns.' These are the colours of wild Asses, and it would appear when these colours are reverted to, certain stripes, which belong to these wild animals, often reappear. In the Zoological Gardens there is a specimen of the Asiatic 1 Study of Animal Life , p. 322. Second edition. 2 Origin of Species (1888), p. 200. F -C t/i I •- c t^ O P.* . oj J- ,G s& 2 & ^2 C O '§>& ^o "3 DAPPLED AND STRIPED HORSES 83 wild Ass (Equus onager). It is dun-coloured, with a broad spinal band like that of Burchell's Zebra, and faint transverse stripes above the hoofs. FIG. 50. — Common Zebra, from a photograph by Mr. Gambler Bolton, F.Z.S. The three Figs. 50-52 show with what perfection and complete- ness striping in the skin can be evolved in the genus Equus. They represent three variations of Zebra, viz., the common Zebra, •n d d h ri J3 M M in d N £ ^ 5 g c £ S 3 3*1 &> £ o _ I » .2 .& O FIG. 53. — Variation of Burchell's Zebra, with obliteration of stripes on legs and haunch, thus approaching the Quagga. DAPPLED AND STRIPED HORSES 87 Burchell's Zebra, and Grevy's Zebra, a new addition from Somali- land,1 which offers an astonishing example of animal striping. At Mr. Rowland Ward's establishment I was shown the skin of what appears to be a variety of Burchell's Zebra. It had the broad striping and arrangement of striping characteristic of that species, but the intermediate paler bands were of a milk-white colour, and without any trace of those faint stripes between the black bands. I noted also that some of the broad black bands were made up of the fusion of two narrower bands. There is another variety which is only partially banded, viz., the Quagga, given in Fig. 54. The article on the Quagga in the Encyclopedia Britannica (Qth Edition) says : * In length of ears and character of tail it more resembles the Horse than it does the Ass. . . . The colour of the head, neck, and upper parts of the body is reddish brown, irregularly banded and marked with dark brown stripes, stronger on the head and neck, and gradually becoming fainter, until lost behind the shoulder.' The haunch and legs have no stripes,2 and it approaches the character of Burchell's Zebra of Fig. 53. Indeed, it has been frequently confounded with the latter by hunters. The Quagga was very common in South Africa, but now is very scarce. In my opinion, the Zebra stripes, like those of the Tiger and other feline animals, owe their genesis to spots or rosettes or dapplings, which had become disposed in transverse rows, some- what like those on the Cheetah of Fig. 10, and on the legs of the Jaguar of Fig. 4. Subsequently the rows of spots coalesced into beady bands, and ultimately became the sharp-edged bands we see in the Zebras. 1 It has also been found on the shores of Lake Rudolf (narrative of Count Samuel Telekis' expedition in Equatorial Africa). Figure of the skin in Proc. ZooL Soc. of London, 1890, p. 413. 2 There is a variation of this in the Science and Art Museum of Edinburgh. DAPPLED AND STRIPED HORSES 89 The Zebra has arrow-head marks on its shoulder. The domestic Cat of the British Museum, although partially spotted, has similar arrow-head marks in the same place, so has the Cat of Fig. 28, and the Tiger of Fig. 22, on the hind-legs. The rows of spots on the fore-legs of the Jaguar (Fig. 4) are disposed in arrow- head rows. In the case of the spotted and striped Cats, as we have seen, it is comparatively easy to make out the derivation of the Tiger stripes from those of the Leopard rosettes ; but it is not so easy to make out the derivation of the Zebra stripes from the spotting of the dappled Horse. I have endeavoured to develop this idea as far as I could by means of existing examples which show the partial transition of dapples into bands. Further on, in Fig. 56 (a, by c\ I have shown that originally the resetting of the Horses must have been closely assimilated to that of the Jaguar. The remainder must be left to the imagination of the reader, taking into consideration analogous transformations in the Leopards and Tigers. We should note that the stripes in Zebras and Tigers, although they are transverse on the trunk, those on the legs are not a con- tinuation of those on the trunk, as in the brindled Dog, but are also transverse, and correspond to the rows of leg spots of the Jaguar and Leopard. This order of things I have tried to account for as a result of inheritance from similar features in widely different ancestors. With regard to the Ass, the only cases I have seen with vestiges of spots are those given in the Appendix C, Nos. 30 and 31. I have, however, seen several little Donkeys at the sea-side which had partial Zebra stripes. Martin l says, ' While speaking of the white colour of some 1 History of the Horse, by W. C. L. Martin (1845), p. 205. 90 STUDIES IN THE EVOLUTION OF ANIMALS breeds of the Ass, and the dappled markings of others, we may observe that a variety with Zebra-like stripes upon the limbs, to the very hoofs, is not unfrequently to be met with in our island and elsewhere, and sometimes even a double cross upon the shoulders is to be seen. To what cause the Zebra markings on the limbs (and we have seen them strongly painted in mules) are to be attributed, it is not easy to say. Is there, or has there been, a striped wild Ass indigenous in Asia,1 or does this style of marking proclaim a cross at a remote date with some African species of the Zebra section ? ' According to my view, all Horses and Asses and Zebras were originally spotted, or have descended from spotted ancestors. A large number among the domestic Horses have retained, or perhaps re-acquired, their spotting. From the spottings there resulted stripings. The Zebras have retained, or may have re-acquired, their striping. The wild and domestic Ass has got rid of both spots and stripes, but in some instances it has retained, or possibly re-acquired, some vestiges of striping. The same may be said of the self- coloured Horse, especially the dun-coloured Horse, the Kattiawar Horse, and the Mule. They frequently show vestiges of striping, and, as I said, the domestic Ass in two cases had vestiges of spotting or dappling on their flanks. When a character ceases to be useful, it begins to disappear, and may become quite suppressed, while some other character more useful may take its place. Fig. 55 is a picture of a ' Dhobi's ' Donkey. I got it copied by a native artist. The original drawing is now in the Lucknow Museum. I have seen a somewhat similarly marked Ass in a picture which was hung in the refreshment room of the Army and Navy stores. 1 We call the wild Ass an Ass, and the wild Zebra a Zebra, because they are differently marked, but in reality they are both Asses. i DAPPLED AND STRIPED HORSES The question might now arise — If the striping of the Zebra is only a modification of some sort of ancestral Horse-dappling, why have not the stripings of the Zebra any signs whatever of their component spots or patches ? FIG. 55. — Picture of a Donkey in the possession of an Indian washerman. Well, why have some Horses no trace whatever of dappling ? Of course the spotting disappeared like many other things that become extinct. This disappearance is one of the great features of evolution. Atrophy first and total suppression later on ; and 92 STUDIES IN THE EVOLUTION OF ANIMALS in colouring first faintness and then total disappearance, if circum- stances do not allow of a part, or a colour, continuing. Moreover, many Tigers in their striping show no evidence of its having originated from spotting. Yet if one makes a close analysis of the striping of a number of Tigers and the spotting of a number of Leopards, he can hardly remain unconvinced that the striping of the Tiger, though prima facie without traces of its origin, owes its genesis to ancestral spotting. The reader may perhaps think that I have been drawing some- what on my imagination, and seeing things which may not be visible to others. But in the colossal museum of the streets of London, if any one feels disposed to study this interesting subject, by directing his attention to it, and by keeping his eyes open, he can amply satisfy himself that what I have stated is founded on fact. In this connection it may be instructive to tell a little story. On one Sunday I accompanied to the Zoological Gardens a lady who was a Fellow of that Society. In going through the Lion and Tiger department, I pointed out how distinctly the Leopard spots could be seen on the legs and abdomen of the Lion. She said, ' Do you know, I have been here hundreds of times, and have never seen those spots before ! ' It is impossible to find in the same Horse all the features I have been discussing ; one may be found in one, and another in another, because, like clouds, the dapplings shift ; but one has only to put two and two together, and invoke the aid of the ( law of proba- bility,' to come to conclusions similar to my own. I have not, however, exhausted all the facts that can be adduced in support of my contention, viz., that the dapplings of the Horse are only greatly modified maculations of a nature origin- ally not unlike those of the Jaguar, and that the striping of the Tiger and Zebra have originated from the stringing together — neck- 93 lace fashion — of spots, like those of Fig. 38 (upper Horse), which by further fusion were modified into clean-margined stripes. The similarity between the stripes of the Tiger and the Zebra can be seen at a glance ; but the similarity between the spotting of the U ' o FIG. 56. — (a) Rosettes from the flank of an omnibus Horse of a strawberry roan colour (reduced) ; (6) rosette from the groin of a highly dappled grey Horse ; (c) one of many rosettes on the flank of a dappled grey cart Horse ; (d) marks on the flank of a brown Horse. Jaguar and that of the Horse is not so easily traced, and has to be evolved with the aid of the imagination out of the variations pre- sented by hundreds of specimens. Nevertheless in Fig. 56 (a) I am able to give bona fide rosettes from the flank of a newly-clipped strawberry roan Horse. They 94 STUDIES IN THE EVOLUTION OF ANIMALS are the marks I had long been searching for, under the conviction that, if my theory were right, I would discover them somewhere. They are rarely seen, because in the Horse the components of each rosette have fused into a continuous maculation, like those of Fig. 34. (&) Is a solitary rosette with its central space split into two portions ; (V) is one of many similar rosettes on a Horse ; and (d) were marks of a slightly different shade of colour from the general coloration of the Horse. Those of (a) are almost exactly like my restoration of the Jaguar rosettes of Fig. 70. I do not, of course, mean that the dappled Horse will ever turn into a Zebra ; or the resetted Jaguar into a Tiger. But I do think it quite conceivable that the striping of the Tiger evolved out of resetting like that of the Jaguar ; and that both the Zebra, and the dappled Horse may have evolved out of an animal with spotting not unlike that of the Jaguar. As to the relation of the Horse-dap- pling to the Zebra-striping, it only requires that one should keep his eyes open in the streets to see on the neck of dappled Horses, especially of Ponies, a decided tendency to Zebra-striping, which is often continued into the Horse's mane. As I said, all experts agree that the Horse is born self-coloured,1 and whatever the cause may be, if this state of things continues, the Horse will be a self-coloured animal ; otherwise he will be more or less dappled. The variations and gradations in the appear- ance and disappearance of spotting in animals are infinite. Some acquire spots at different ages, others lose them at different ages. Just as the embryo of the higher animals in evolving simulates the different stages of form through which, in its race history, the animal ascended, so the spotting and marking may give indication of the ancestral markings through which that animal in its evolu- tion may have passed. 1 Like the small Jaguar cub in the Natural History Museum — case 13. DAPPLED RUMINANTS 95 There cannot be much doubt that the Kiangy or wild Ass, originated from a Zebra-marked ancestor. In the Origin of Species, p. 199, it is stated, on the authority of Colonel Poole, 'that the foals of this species are generally striped on the legs, and faintly on the shoulder.' In the adult they totally disappeared excepting the spinal stripe. So have the markings disappeared from the hind quarters and legs of the Quagga (Fig. 54). Now let us turn for a moment from the Horse, the coloration of which I think I have sufficiently discussed, to another set of animals, viz., Giraffes and Bulls. From Fig. 57 it will be seen that the large blotches of the Giraffe are separated from each other by a lighter ground. These blotches may be nothing more than a confluence of a number of rosettes, such as we see on the shoulder of Fig. 34, or those on the fore-leg of Fig. 36. Indeed, on the shoulder of one of these figured Giraffes (left one), there are two blotches which seem distinctly to be made up of several smaller blotches. Cows and Bulls are rarely seen with any vestigial marks of ancestral spotting or resetting ; but the Bull of Fig. 57, on its flank, shows distinct spotting not unlike that on the flank of the Horse in Fig. 37. Then I think no one will say that the striking resetting on the flank of the Zebu of Fig. 58 is not almost identical with that on the shoulder and fore-leg of the Horse in Fig. 36. The very extraordinary marks of this Zebu, so uncommon among domestic cattle, leave no doubt in my mind that the ruminants and the Horse are more closely allied than may have been supposed. Faint similar marks on the hump, abdomen, and haunches, lead to the presumption that in some ancestral ruminant the whole skin was covered with similar rosettes. Now domestic cattle are either blotched, piebald, or self-coloured ; and D,eer and Antelopes are either spotted, striped, or self-coloured. FIG. 57. — Giraffes and Bull, all three from photographs by^Dixon & Son. DAPPLED RUMINANTS 97 The Giraffe and the Zebu are the only ruminants, the one in a state of nature, and the other domesticated, which continue to reproduce distinct vestiges of ancestral skin markings, allied to those of the FIG. 58. — Zebu, from a photograph, F. G. O. S. , 10004. Horse and the Jaguar. Indeed, if the rosettes on the flanks of the Jaguar skin of Fig. 4 had their enclosed spaces filled up they would become Giraffe blotches, and if we trim the rosettes of the Zebu and fill in their scolloped margins, we again reproduce the blotches of the Giraffe. In the Quagga we have seen that the stripes dis- G 98 STUDIES IN THE EVOLUTION OF ANIMALS appeared from the hind quarters and legs ; so in the Giraffe we see the blotches disappearing from the under surface and legs. Recently a new Giraffe has been discovered in Somaliland, and a description of it appeared in the Saturday Review of 2ist July 1 894, p. 72. It is distinguished from the South African Giraffe ' by a complete and whole body colouring of rich bright chestnut (I suppose the chestnut colour of the horse), scarcely separable by very fine,1 almost invisible lines of creamy white of hexagonal shape ; ' while * in its South African cousin the markings are widely and clearly defined,' as seen in Fig. 57. Hunters in South Africa have often described the Giraffe as of a chestnut colour. This colour is common to the Horse and the Ox. This ' new Giraffe ' does not appear to differ from the ' old Giraffe ' any more than one grey dappled Horse differs from another grey dappled Horse. Compare different parts of the Horse in Fig. 34. In parts the reticulations are fine, in others they are broad, and in Fig. 37 they are still broader. 1 At Rowland Ward's I was told that the divisions between the polygonal blotches were about one inch broad. MEANING OF THE JAGUAR AND LEOPARD ROSETTES AND OF THE MARKINGS OF OTHER MAMMALS ' But, as soon as the attempt is made to think out the process in detail, we recognise that here, too, we know nothing thoroughly, and that it would be uncommonly easy for any one who wished to assign the processes of natural selection altogether to the realm of phantasy to emphasise this view : for it is really very difficult to imagine this process of natural selection in its details ; and to this day it is impossible to demonstrate it in any one point.' The All-sufficiency of Natural Selection, by Professor AUG. WEISMANN, Contemporary Review, September 1893, p. 322. PART III MEANING OF THE JAGUAR AND LEOPARD ROSETTES AND OF THE MARKINGS OF OTHER MAMMALS THE groups of spots, or rosettes as they are called, which these two animals present, are so characteristic that they must have some meaning, which hitherto, as far as I am aware, has not been worked out, or perhaps not worked out according to what, in my opinion, is the true meaning of the rosettes. What can that meaning be ? The Leopard spots, as we have seen, are merely contractions of those of the Jaguar ; and may be the Cheetah spots are still further contractions and modifications of those of the Jaguar. The larger rosettes of the Jaguar consist, as we have seen, of a certain space enclosed by a polygonal ring of spots (Fig. 4). The space enclosed has either one or several still smaller spots,1 and sometimes none ; and its colour is often different from the general ground colour. In Fig. 59 I have given a number of variations of Jaguar and Leopard rosettes, and also some groups of Cheetah markings. It is perfectly clear to me that in Nos. 10 to 13, and others, a fusion of some of the ring-spots has taken place, and a larger irre- gular patch has been the result ; that in Nos. 3, 4, 5, 7 and 14, a 1 Ordinary Leopard skins sometimes show a few rosettes with specks in the enclosed space. IO2 STUDIES IN THE EVOLUTION OF ANIMALS fusion of the whole ring-spots has occurred ; and that in Nos. i and 2 a still further fusion and contraction has resulted, obliterating the FIG. 59. — Nos. 5, 8, 9, 12, 13, 19, 26, and 30-32 are from Jaguar skins ; Nos. 33-35 are from Cheetah skins ; all the rest are from ordinary Leopard skins. enclosed space. Several of the rosettes indicate transition stages towards partial or complete fusion. On the other hand, Nos|26, 29, 30 and 3 1 would indicate a dissociation and tendency to scattering of the component spots of rosettes. MEANING OF JAGUAR AND LEOPARD ROSETTES 103 The solid rosettes, Nos. I and 2, and other forms of solid rosettes, are to be found mainly along the spine and on the abdo- minal surface ; while the dissociated rosettes shown in No. 32 are from the shoulder of the Jaguar. For reasons to be seen elsewhere I would consider No. 3 1 as the typical Jaguar rosette from which all the other modifications have resulted. The fused ring, when it occurs, may be either circular, polygonal, oval, or beaked, as seen in Nos. 3, 4, 5, and 7. It will be seen that the enclosed space, which is often of a different shade x from that of the general ground colour, sometimes contains one or more minute spots or specks, as in Nos. 27, 30, and 31. Then No. 33 is a group from the flank of a Cheetah in the Natural History Museum, No. 34 is from a similar animal in the Zoological Gardens, and No. 35 is a group from the haunch of a Cheetah in the Science and Art Museum of Edinburgh. These rosettes have been taken from various skins, but I think most of them can be matched from the skins of Figs. 4-7. If the reader would take a pencil and draw outlines of the different variations in the rosettes of the skins given, he would be astonished with their variableness. Stretching of certain parts of the skin might perhaps, as I said, partly account for dissociation, and pressure and contraction might cause fusion, but I do not pretend to explain how all this occurs. Some idea of the process may per- haps be got by stating that in the embryo, while all the parts are semi-fluid, the pigment cells attract each other and fuse into bigger drops, just as minute discs of oil floating on water would now and again fuse into bigger discs if they came in contact, or would form groups of discs huddled together, and separated only by a capillary film of water. This obviously would not account for the fact that, along the 1 Note this. io4 STUDIES IN THE EVOLUTION OF ANIMALS spine, and on the abdomen, the rosettes coalesce into solid blotches, while on the flanks and shoulders they do not. This fusion and dispersion are evidently under the control of the nerve-centres, where modifications originate, and are only made appreciable by modified markings on the skin. But, really, why the rosettes remain as rosettes on the flanks, and why they are dispersed on the shoulders of the Jaguar, while they coalesce and form solid blotches along the spine and other parts, I am unable to make out. Prof. H. B. Orr l says : ' Any single nervous reaction, in a connected and often repeated series, does not disappear the instant its original stimulus is withdrawn. It will last for some time after- wards under the influence of association with the rest of the series. Eventually, however, it must disappear, sooner or later, according to the firmness of the association.' In the Jaguar and Leopard it would appear that the nervous action is very late in disappearing, although they have been running on parallel lines with Lions and Pumas for thousands, and, may be, millions of years. They afford us an example of the persistence of influence, although the stimulus may have been withdrawn ages ago, while in Lions, Pumas, and others the markings have almost wholly disappeared. It has been stated 2 that, at the Marine Laboratory of Plymouth, experiments on the under surface of flat fishes have been made by means of mirrors reflecting light from below. The under surface of the fish first became spotted, then the spots amalgamated, and finally the entire under-surface became dark. Photographs of the different stages have been taken. According to Prof. Lodge, light is electricity, and experiments 1 A Theory of Development and Heredity, p. 199. 2 Chambers' s Jotirnal to\ August 26th, 1893, P- 541- MEANING OF JAGUAR AND LEOPARD ROSETTES 105 may yet teach us a great deal about animal coloration and mark- ings. The markings of the Jaguar, however, I think are due, not to the action of light, 'but to a totally different cause, as I hope to show. Mr. Poulton l considers it proved that the white hair of certain Arctic animals is caused by the low temperature of the winter. Quoting from Mr. Welch, he says that in the American Hare, on the approach of winter, the dark hairs of the old coat turn white, commencing either at the tip, the middle, or the base of the hair, and that in addition there is a new winter coat coming up of an entirely white colour. And at p. 103, Mr. Poulton says that the young of the Arctic Hare are born grey, and turn white at their first winter. All this does not affect the fact that in dappled grey Horses the spots are white, in dappled brown and dun Horses the spots are lighter than the ground colour, in roans they are black, and in strawberry roans they are bay or brown. Moreover, I have seen a grey Horse with tan-coloured spots.2 So with many other animals that might be quoted. It is clear that in these cases temperature can have nothing to do with the difference in coloration, and we have to search for other causes to account for the coloration of certain animals, and more especially for those extraordinary mark- ings we see in the Jaguar, the Leopard, the Cheetah, the Tiger, the Zebra, and so many other mammals. A study of the rosettes in Fig. 59, and many others that can be seen on skins, makes it evident to me that, whatever may be the initial atomic nervous influence which produces these variations, they result in two sets of modifications, (a) a fusion of some or of all the encircling spots, and often in an obliteration of the enclosed space ; or (b) a dissociation of the encircling spots, and perhaps even a scattering of the enclosed specks. 1 Colours of Animals, p. 95. '2 See Appendix C. i o<5 STUDIES IN THE EVOLUTION OF ANIMALS Between these two extremes, numerous intermediate variations of the rosettes occur, as the reader can see for himself. I particularly dwell on the markings of the Jaguar, because they appear to me to be the typical markings, out of which many others we see in various animals have been elaborated or evolved. It would be idle to suppose that each separate group of spotlets, forming a rosette, was made as it is by a process of natural selection. Such a notion would be wholly untenable. All the rosettes have a family resemblance, and therefore must have had a common origin. Natural selection may have had something to do with maintaining the general character of the spotted skin, but it could not possibly have had anything to do with moulding the outlines of each individual group of spotlets. We must therefore look for a cause or causes of these markings which, at the same time that they allowed them to vary, stamped them with the features of a common parentage. If the Leopards have retained (not acquired) their very peculiar markings, so different from those of the generality of mammals, it would seem to follow that these animals emerged out of some more ancient mould with these peculiar marks. Their common family resem- blance would point to their being modifications of a still older form of rosette, viz., that shown in No. 31, Fig. 59. How then did this more ancient form of rosette originate ? — by natural selection or what ? Before I attempt to reply to this question in my own way, I would like to show how others have looked at it. Dr. Wallace, in Darwinism, p. 288, says that Mr. Tylor * called attention to an important principle which underlies the various patterns or ornamental markings of animals, viz., that diversified coloration follows the chief lines of structure, and changes at 1 Coloration in Animals and Plants. MEANING OF JAGUAR AND LEOPARD ROSETTES 107 points, such as the joints, where function changes. Mr. Tylor says : ' If we take highly decorated species — that is, marked by 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 ; 1 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 ; 2 fourthly, that the shoulder and hip regions are marked by curved lines ; fifthly, that the pattern and the direction of the lines or spots change 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.' Then at p. 289, still quoting from Coloration in Animals and Plants, Dr. Wallace says that * Mr. Tylor was of opinion that 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 as the animal grows older ; then the stripes expand, and at last, meeting together, the adult animal becomes of a uniform brown colour.' And on p. 290, Dr. Wallace says : ' 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. 1 Sometimes it is white, as in certain Antelopes, and also in the Kerry breed of cattle. 2 Undoubtedly the markings often cross the ribs, as in the Ocelots and the Viverridce, the Paca, etc. io8 STUDIES IN THE EVOLUTION OF ANIMALS Pigs and Tapirs are banded when young ; an imported young specimen of Tapirus Bairdi was covered with white spots in longi- tudinal 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 the dappled Horses ; and a great number 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. On p. 290, Dr. Wallace also mentions that in certain diseases the pigment is destroyed along the course of a nerve and its branches. In this connection Mr. Darwin says : l * Three accounts have been published in Eastern Prussia, of white and white-spotted Horses being greatly injured by eating mildewed and honeydewed vetches, every spot of skin bearing white hairs becoming inflamed and gangrenous.' Other similar cases are quoted in other animals. ' We thus see that not only do those parts of the skin which bear white hair differ in a remarkable manner from those bearing hair of any other colour, but that some great constitutional difference must be correlated with the colour of the hair ; for in the above mentioned cases, vegetable poisons caused fever, swelling of the head, as well as other symptoms, and even death, to all the white or white-spotted animals.' Some great constitutional difference must be correlated with the colour of the hair. Undoubtedly ; and the starting-point would seem to be the electricity of the nerve-centre cells, corresponding to the white parts of the skin, acted on electrically by the poison in the blood circulating among those central cells. No one who has thought on this subject can doubt that the 1 Animals and Plants under Domestication, vol. ii. p. 331, second edition. MEANING OF JAGUAR AND LEOPARD ROSETTES 109 action of the nervous system influences the pigmentation of the skin, and the distribution of the pigments ; but the nerves them- selves seem to act only as conductors of the changes and influences which lie deeper in the cells of the nerve-centres. In electro-plating the wires conduct the influence of the action in the battery, and the metal is separated from the solution, and is deposited on the plate, or is dissolved off again, and returned to the solution according to circumstances. So in the pigmentation of the skin, the influence of the nerve-centres, acting through the nerves, puts on or takes off pigment, and modifies it according to circumstances. Now the action of the nerve-centres depends on the blood, and the blood depends on food and physical surroundings. But in addition to all these, heredity undoubtedly plays a great part in all these phenomena. And in order to answer the question I put, we have to go back to features of still more ancient animals, which are now wholly extinct, viz., of that large class of animals which carried armour plates on their skin, as part of what is called an exoskeleton. In remote times there were numerous animals protected by plate-armour ; some of these have continued as survivals up to our time — such as Armadillos, Turtles, Crocodiles, Sturgeons, and many other curious fishes. Indeed, if we go lower down in the scale of life, we find that the exoskeleton is the only solid part of the animal structure, such as we see it in Crabs, Lobsters, and other A rthropoda. Among armour-plated animals, now extinct, were several known species of Glyptodonts, like that shown in Fig. 60, the fossil original of which is in the Natural History Museum. The armour of these strange animals consisted of either circular or many-sided plates, encircled by a rim of smaller polygonal MEANING OF JAGUAR AND LEOPARD ROSETTES in platelets, like those of Fig. 61 («), (b\ (c\ (g). The form of these bone-rosettes varied not only in different species, but also in the same individual. In the Natural History Museum, besides the Great Glyptodon, there are fragments of the carapaces of other species, as shown in Fig. 62. qp o FIG. 61. — Bone-rosettes of various Glyptodonts (reduced) : (a) from carapace of Glypotodon asper; (b) from front, and (c) from back of head-shield of ditto (Natural History Museum) ; (d) from G. Clavipes ; (e) from G. ornatus ; (/ g and ti) from other Glyptodonts in the Royal College of Surgeons ; (i) groups of tail plates of a Glyptodont (Natural History Museum). Then in the museum of the Royal College of Surgeons there are remains of other forms of Glyptodonts, with bone-rosettes which perhaps are still more suggestive. In Fig. 61 (d)t (e\ (/), (<£")> W> some of these rosettes are shown. As these bone-rosettes1 are taken from fossil remains, the edges of the component plates, and in some cases their surfaces, 1 In the Natural History Museum, the plates of the Carapace of the Glyptodon and Armadillo are called 'ossification of the derm.' 112 STUDIES IN THE EVOLUTION OF ANIMALS may have become partially eroded. Indeed, in some fragments, the platelets are almost wholly defaced, as shown in Fig. 62 (#). But I think that any unprejudiced evolutionist will not fail to see FIG. 62. — Bone-rosettes from other species: (a) from carapace of Hoplophorus ; (b] from carapace of H. Megeri; (c] from fragment of a Hoplophorus (Natural History Museum). in them the ' blocks/ so to speak, from which the Jaguar got its imprints \ Moreover, on the pelvic shield of Polacanthus Foxii, Fig. 63 (a), the remains of a Stegosaur in the Natural History Museum, and on the tail armour of a Hoplophorus, (b) we find armour-plates MEANING OF JAGUAR AND LEOPARD ROSETTES 113 like those on Fig. 61 (g), which assimilate better perhaps with the typical Jaguar rosette shown in No. 31, Fig. 59. Here I would note that the lumbar shield of Tolypeutes tricincta, FIG. 63. — (a) Armour-plates of Polacanthus Foxii (Stegosauria) (reduced) ; (b] plates from the tail of a Hoplophorus (one-third natural size) from Fig. 1164, Nicholson & Lydekker's Palceouiology, vol. ii. ; (c] plate from Tolypeutes tricincta \ (d] plate from Priodontes Peba. an existing Armadillo, is composed of plates like those of Fig. 63 (c], and those of the Peba Armadillo (Priodontes Peba) are like those of (d) of the same figure, both which assimilate with the markings of the resetted Cats. a •• FIG. 64.-- -(a) Plates from shoulder and lumbar shields of Tahisia Peba, the seven-banded Armadillo ; (b} plates from the Great Armadillo, Priodontes maximus. — (Natural History Museum. ) Of course in some of the modern Armadillos the shield plates are much altered, but anybody can see that they consist of the same elements as shown in Fig. 64 (a\ In (b) they are still more H STUDIES IN THE EVOLUTION OF ANIMALS altered, and not impossibly the rim of each plate in this case is a fusion of the ring of platelets of others. In Elliot's monograph of the Felidce I met with a very curious assimilation between the disposition of plates on the forehead shield of an Armadillo, and the disposition of the coloration on the forehead of a domestic Cat. The latter forcibly recalls the former. Both are shown in the accompanying Fig. 65. I have seen this forehead mark in other domestic Cats. Those specks which we see on the Jaguar skin, enclosed within the ring of FIG. 65. — (a) Mark on the forehead of a domestic Cat (Elliot's Felidai); the centre is brown, edged with black, and surrounded by a light ground ; (b] forehead shield of an Armadillo, shown under the paw of F. Yaguarundi (Elliot's spotlets, such as those of Nos. 26 to 28, Fig. 59, may just be the modified imprints of the little knobs we see on the hexagonal plates of Tolypeutes, a kind of Armadillo (Fig. 66 (d) ). But recently Mr. Lydekker has possibly imparted to these inner specks a special interest. In No. 101, new series, of Knoivledge, March 1894, Mr. Lydekker has described the club-tailed Glyptodont of Argentina. Each plate of this animal's carapace has several holes in it, which the writer supposes gave passage to spines. Whatever they may have given passage to, it strikes me very forcibly that the specks in the interior of the Jaguar rosettes,1 or imprints, as I would call them, of ancestral carapacial plates, may possibly be the imprints 1 I have seen rosettes on a Jaguar (Tring Museum) with as many as six specks. MEANING OF JAGUAR AND LEOPARD ROSETTES 115 of holes similar to those on the plates of this curious Dczdicurus, now in the La Plata Museum ! In past ages there were numerous carapaced animals even as low down as the fishes. Although I have been stating that the Jaguar and other Cats probably descended from Glyptodontoid ancestors, I do not mean that all the Cats descended from the same pair of ancestors, for it is obvious that some may have descended from one species, and others from others. Afterwards they may have intercrossed, just as they are able to do now. For instance, in the Cheetah, the marks are different from those of the Jaguar, FIG. 66.— (a) and (b] are from Ostracions in the York Museum ; (c) from another Ostracion, an armoured fish ; (rf)from pelvic shield of a Tolypeutes, an Armadillo (from Fig. n6i,-vol. ii. of Nicholson and Lydekker's Palavntology}* and in the Horse we see transitions of marks which are like stars. Here are some patterns of plate armour for the reader to choose from (Fig. 66). It maybe asked, If other spotted animals have so much altered, why has not the Jaguar ? Well, somewhat similar questions are often asked by women— * If we came from Monkeys, why do not Monkeys now turn into men and women ? ! ' The answer is obvious to the mind of an evolutionist. The ancestral form, like every living thing, must either live or die. If it have endurance in its constitution, and is also suited to its surroundings, it will endure side by side with the variations which originated from it. In some n6 STUDIES IN THE EVOLUTION OF ANIMALS cases it may endure better, and the variations may become extinct ; while in other cases, the variations may endure better, and the parent form may become extinct Thus we see Monkeys themselves varied in a hundred ways, enduring side by side with man, who possibly originated from the Monkey-plane, and they may continue to endure until perhaps they become his rivals, and competitors for the consumption of his crops. Professor Parker l says : ' Why such a form as the Glyptodon should have failed to keep his ground is a great mystery ; nature seems to have built him, as Rome was built, for eternity. His exquisite little relative, the Chlamydophorus, scarcely larger than a Mole, has continued as yet to run out of danger, safe in his little- ness ; and many other kinds of low-brained mammals have, so to speak, the power to make themselves practically invisible.' In another place I have ventured on a speculation which may account for the descendants of the Glyptodonts losing their carapace. All these armour-plates of existing and extinct animals are most suggestive, and I consider them very important elements in the interpretation of the rosetting of the Jaguar. After the armoured animals lost their skin-stiffening of lime deposit, the imprints of armour-plating must have become vastly more subject to modification than before, and so we have the endless forms of spotting and marking in mammals. After millions of generations that have been born since the Glyptodonts, and other Armadilloid animals, lost their bone-plates, it cannot be expected that the skin should retain the original outlines of plates un- changed. The great wonder is that the Jaguar has retained the features of its ancestral bone-plates with so little modification \ As an instance of the slowness, under favourable circumstances, with which long established characters are got rid of, both from the 1 Mammalian Descent, p. 94. MEANING OF JAGUAR AND LEOPARD ROSETTES 117 body and from its ruler the brain, the rosettes of the Leopards may be quoted. Who can tell how many millions of generations have elapsed since the ancestors of these animals and their congeners threw off their calcareous carapace, and adopted a masquerade of pigment-rosettes instead ? Yet to this day this masquerading goes on in the Leopards and Jaguars, in their black varieties, as well as in the Snow Leopard. They are unable to shake off this pigment dress inherited from a calcareous carapace, although their habits and customs, their entire skeleton and teeth, have undergone great modifications. a. FIG. 67. — Bone-rosettes from the carapace of the Glyptodon, Natural History Museum, (a) partially fused rosettes from front of carapace, (b) distinct rosettes from side of carapace. It must not be supposed, however, that bone-rosettes are not subject to fusion and other modifications. Fig. 67 (a) shows two bone-rosettes with a tendency to approximate and partially fuse ; while (#) shows them quite distinct, and are given for comparison. Hitherto I have traced the similarity of the Jaguar rosettes with the bone-rosettes of Glyptodontoid and Armadilloid animals which are also mammals. But chi cerca trova ! Strange to say, this similarity can be traced much further down in the scale of life, and therefore much further back in time. Among the Chelonians we seem to find the identical mould from which the Glyptodon derived its bone-rosettes. The Leathery Turtle (Derniochelyk coriaced) has thin mosaically n8 STUDIES IN THE EVOLUTION OF ANIMALS disposed plates on its carapace which at first sight seem a con- fusion of platelets without any order ; but further investigation reveals on the right side,1 below one of the longitudinal crests, the fact that several of them are disposed in distinct rosettes FIG. 68. — (a) Bone-rosettes on the carapace of the Leathery Turtle (Dermoc/ielys coriacea) ; (b] crested plate of Nile Crocodile, encircled by small plates from right flank ; (c] crested plate of Sturgeon (Accipenser sturio] seen between the larger plates on the spine and flank ; all from the Natural History Museum. exactly like those of the Glyptodon, as shown in Fig. 68 (a). Curiously enough, this Turtle is one of those whose carapace is not like that of other Turtles, fused with the spine and ribs. There is therefore some suspicion that it may be one of the ancestral forms of such mammals as the Glyptodonts, otherwise it would be strange 1 Specimen in Natural History Museum. MEANING OF JAGUAR AND LEOPARD ROSETTES 119 that the Leathery Turtle should exhibit the identical bone-rosettes of the Glyptodon. They are no doubt very much thinner, as if they may be either forming or disappearing ; nevertheless, no one can doubt that they are the same things, and are produced by the same cause, whatever that may be. It is also noteworthy that two of the Turtle rosettes show a tendency to approximation and partial fusion, like those of Fig. 67. This community of features points to the probability of the Glyptodonts having emerged from some Turtle-like water-animal. n°p< °n> FIG. 69. — (a) Group of ornament tubercles on head-shield of Encephalaspis Pagei (Prof. E. R. Lankester's Monograph of the Fishes of the Old Red Sandstone of Britain, p. 49). The scales have the same character of markings ; (b] ornament in polygonal plates tuberculated of Hemicyclaspis Murchisoni, p. 52; (c] Portion of test or shell of Echinus gracilis (Zoology of the Invertebrata, by A. E. Shipley p. 241). Then the Nile Crocodile and the Sturgeon show in their armour forms of plating similar to the imprints of the Jaguar, as seen in Fig. 68 (b) and (c]. Lower and lower still in the scale of life we meet with the same curious pattern in its more primitive form, viz., that of a central larger plate surrounded by a ring of smaller plates or tubercles. I would not venture to suggest that the spotting of the Cheetah has any relationship with the plates on the test of the Echinus, or with those of armoured fishes ; for, if I did, I might be laughed at, and there- fore I simply give the markings on these animals in Fig. 69 so that the reader may judge for himself. 120 STUDIES IN THE EVOLUTION OF ANIMALS (a) Shows the ornamentation on the head-shields of Encephalaspis Pagei, an extinct Sturgeon-like fish ; (U) shows a plate from Hemi- cyclaspis Murchisoni, an extinct animal like an Armadillo ; while (c) are from the test of an Echinus. Then, curiously enough, the Pearly Nautilus in the Natural History Museum, on its soft hood exhibits a similar pattern, al- though it does not seem to have there any calcareous deposit. The soft hood appears to act as an operculum when the cephalopod withdraws into its chamber, and therefore may at one time have been armoured. It would seem preposterous to endeavour to carry on the relationship of the Jaguar and Cheetah markings to those on the armour of the Cephalaspidae,1 or the Echini. Yet if we are evolu- tionists, and if creation by the method of evolution be true, the Echinus and other low forms cannot be left out in the cold because such hints as I have made would outrage our feelings ! We must look upon the markings of certain fishes and of the Echini as connected somehow with those of the higher land animals. Evolutionists go even further than this, and admit that all animal forms on the earth were evolved from the minute pelagic forms, many of which are still in existence. The doctrine of evolution would teach us that all these phenomena are rather a matter of course than mere unexplainable anomalies. It does not, I think, require much acumen to see a family resemblance between the figures of the Glyptodon's bone-rosettes and the spot-rosettes on the flanks of the Jaguar. Indeed, a glance at the back and flanks of Fig. 4 will readily suggest the impression of a carapace composed of plates not dissimilar to those of the Glyptodon. I do not say that the Jaguar descended from a Glypto- don, but I do say that this mammal descended from some extinct 1 The Cephalaspicfoe were Sturgeon-like ancient extinct fishes. MEANING OF JAGUAR AND LEOPARD ROSETTES 121 animal with a GlyptodonA?/^ carapace. - I repeat that the bone- plate rosettes on Figs. 61 and 62 speak to us only too plainly. These armour-plates of extinct animals are to my mind the ' blocks ' which gave the Jaguar skin the impressions of the groups of spots or rosettes, much modified in subsequent innumerable generations. In other words, the skin, on losing its hard calcareous plates, retained somehow an impression of them, which modified the pigmentation, where the plates in its ancestors originally stood. Or again, to put it more ' nervously,' the action of the nerve-centres which caused the deposition of calcareous matter in rosette-form, on the skin of the Glyptodonts, continued to act when there was an insufficient amount of calcareous matter in the blood for this purposed That is, in the nerve-centres a sort of memory of former plates remained, which expressed itself in pigments after the calcareous carapace had gone. This nervous action then resulted in the deposition of pigments of colours different from those of the general skin. In many mammals this nervous action dwindled into the deposition of simple spots ; in others it fused them into lines and patches, and in some they were entirely obliterated, as in the adult Puma and others. The intervals between the Jaguar and Leopard rosettes — now altered, as I said, through innumerable generations — would seem to indicate the sutures between the armour-plate rosettes of some ancestral Glyptodontoid animal. Of course the skin of the Jaguar is elastic and mobile, and stretches readily to adapt itself to the growing animal and to the different variations in size which we see in the Cat tribe. Its elas- ticity would seem sufficient to account for the broadening of the network of sutures which we see everywhere between the Jaguar rosettes, and perhaps also for the dissociation of the spotlets which 1 In the Natural History Museum there is an interesting series of skins of Lacertilia ; some have fully ossified scales, others have only vestiges of ossification. 122 STUDIES IN THE EVOLUTION OF ANIMALS compose the groups on its shoulders (Fig. 4) ; and not improbably the stretching of the skin might partially account for the charac- teristic spotting on the haunch of the Cheetah shown in Fig. 59, Nos. 33-35. In Fig. 70 (a) I have endeavoured to restore some of the plates of the carapace of the Jaguar's immediate ancestor. Of course this restoration is imaginary, but it is suggested by five contiguous rosettes on the Jaguar's left flank, behind the shoulder (Fig. 4). I FIG. 70. — (a] Restoration of the rosettes of an imaginary Glyptodontoid ancestor of the Jaguar, with closely interlocking plates ; (/>) The same in subsequent forms of mammals, when the plates may have become dissociated, with intervening flexible skin. have shown the plate-rosettes as closely fitting in (a) ; but imagine them to have become somehow dissociated as in (b\ from causes which I have already discussed, and you have intervening channels or commissures of flexible skin, such as we see in the Crocodiles, and also between the bands of the Armadillos. These skin com- missures are now represented in the Jaguar by the paler ground colour reticulated between the rosettes. I have given the imagined plates a trapezoid shape, to make them similar to the Jaguar rosettes, but the shape of the latter may have become much distorted, as indeed we see it in various parts of the Jaguar skin itself. I have MEANING OF JAGUAR AND LEOPARD ROSETTES 123 also given five little specks on each central plate, to assimilate them with some of the Jaguar rosettes, but there may have been many more, as in the plates of Tolypeutes. All this imaginary restoration, however, was hardly necessary, as in Fig. 62 (c\ which is part of the carapace of a Glyptodont, shows an almost identical arrangement of bone-rosettes. Reference to Figs. 61 and 62 will show how various the number of small plates is which encircle the bigger central plate. In some cases the inference would be that the smaller plates have occurred to completely fill in vacant spaces left by the larger and more solid plates, and thus leave no part of the skin unprotected. Where great flexibility is needed, as between the bands of Arma- dillos, it is obvious that plates would be an encumbrance, and simple elastic skin preferable. The dissociation of the plate-rosettes, with intervening elastic skin, would have admitted of freer movements — a feature of great importance in the struggle for existence — than would have been possible in the dish-cover solid carapace of a Glyptodont. This dissociation of plate-rosettes is not simply a hypothesis, for we see it actually occurring on the abdomen of the Great Armadillo (Priodontes maximus]^ which in that region has rows of separate rosettes, composed of minute plates, while the carapace is formed of bands of squarish plates, with intermediate skin commissures, like those shown in Fig. 64 (£). It may perhaps be objected, that if the plate-rosettes could be dissociated bodily, the component smaller plates could also be dis- sociated. Just so, and that is what may have occurred in the ances- try from which the Cheetah has descended. Its plate-impressions, large and small, though probably much modified, are scattered all over its skin. 1 Edinburgh Museum of Science and Art. 124 STUDIES IN THE EVOLUTION OF ANIMALS FIG. 71.— The Hairy Armadillo (Dasypus vil- losus], Natural History Museum. In snakes we see closely fitting scales, but in the Python, and in the expanded hood of the Cobra, the scales are scattered over the skin, with intervening spaces without scales. So that stretch- ing of the skin may have had something to do with the scattering of the rosettes, whether as dissociated bone-plates or dissociated pigment-spots. There is another feature in the Leopards which is worthy of notice. On their legs there are transverse rows of small spots. These, in my view, are impressions left by transverse rows of small plates, not unlike those which we see on the legs of an existing Armadillo, shown in Fig. 71. We now begin to get a sort of * moral conviction ' that the transverse stripes on the legs of Tigers, and other Cats, are due to ancestral rows of spots like those on the legs of Leopards, and these in turn are due to the fact that their armoured ancestors had scales or plates there, similarly disposed. In the Hairy Armadillo and others no doubt the leg-plates are in process of extinction. As the animals can roll themselves up in their banded carapace, their leg-plates have become superfluous, and are doomed to extinction. Taking then everything into consideration, I think it will be found difficult to escape from the conclusion that the markings of the Leopards are inherited from ancestral plate-impressions of some extinct Glyptodontoid form, and have not been evolved by a process of natural selection. It is a wonder to me that in the Jaguar so much likeness to ancestral bone-plates still remains as to enable us, through these hieroglyphics, to read the story of its descent. But for these MEANING OF JAGUAR AND LEOPARD ROSETTES 125 Jaguars and Leopards, the ever-recurring variations which we see in living mammals would have prevented us from deciphering mark- ings which are all but universal in mammals, but so strangely altered; for who would have conjectured that the stripes of the Tiger had anything to do with an armour-plated ancestral carapace ? The very fact of those great Armadillos having become extinct may have resulted precisely from the unstretchable nature of their bony skins. Their movements must have been hampered to a vast degree ; and the great difference between their edentate jaws and the jaws of the carnivora is enough to indicate to us the vast changes that must have occurred from the days of the Glyptodonts to those of the existing carnivora. In another place I have shown that the markings of a large number of carnivora are traceable to modifications of the markings of the Jaguar. I have also shown that some Horses have rosettes (Fig. 56 (a)) not very dissimilar to those imaginary ones of Fig. 70. I take the dappling of Horses to mean a fusion of the ancestral Horse rosettes ; and the Zebra banding again as a modification of the ancestral dappling. Then the resetting, spotting, and striping of the ruminants would be further modifications of the original Horse-like resetting. In the ' old Giraffe ' we seem to have a fusion of a number of rosettes to form the polygonal blotches, with broad commissures ; while in the ' new Giraffe ' of Somaliland, the poly- gonal blotches are approximated and the commissures are not so broad. Further on I have endeavoured to show cause for the thinning, disintegration, and the final disappearance of such massive cal- careous carapaces like those of the huge extinct Glyptodonts from which all this picture resetting, spotting, blotching, striping, and banding in existing animals, as I think, have come. After the exoskeleton was got rid of, the internal skeleton went 126 STUDIES IN THE EVOLUTION OF ANIMALS on evolving independently of the coloration of the skin, and that may be the reason why we find almost identical coloration or markings in mammals, with vast modifications in their endo- skeleton. What were at one time solid plates with holes or knobs, became later on expressed in simple pigments of different colours to the great advantage of the losers of such a stiff and unmanageable encumbrance. If it be true that the resetting of the Jaguar and Leopard origin- ated as I have stated in the foregoing pages, the same theory will account for the markings of Horses and other mammals, including ruminants and more especially Oxen, as testified by the rosette markings of the Zebu (Fig. 58). POSTSCRIPT WHILE this book was passing through the press, I read in Knowledge of January 1895 a paper by Mr. R. Lydekker on the ' Spots and Stripes in Mammals,' wherein he gives Professor Eimer's and his own views of the origin of mammal coloration, as he does not seem to agree with Pro- fessor Eimer. I am sorry to disagree with two great authorities on these matters, but Thomas Carlyle's teaching was this — say what you think, even if you are gibbeted for it. I cannot make this subject intelligible to the reader without giving extracts of some length from Mr. Lydekker's paper ; and perhaps it will be better if I take certain points of his paper one after the other, and try to discuss them, as the questions are exceptionally interesting. On p. 3 he says :— 'These markings generally take the form either of longitudinal or trans- verse bands or spots, the latter being frequently arranged in more or less distinctly defined longitudinal lines, but '; never " in transverse bands.' POSTSCRIPT 127 I think I have shown that both in the Leopard and in the Horse spots do not infrequently arrange themselves in transverse lines or series. P. 4. 'A similar state of things occurs among wild Pigs, and also in Tapirs, from which we are naturally led to infer that in this group of mammals, at least, a spotted or striped type of coloration is the "original" or generalised con- dition, while a uniformly coloured coat is an acquired or specialised feature, and we shall find that this will hold good for other groups.3 In my humble opinion — and I have tried to show why I hold this opinion — both the striped type of coloration and the uniformly coloured coat are derived from the spotted or rosetted types. In writing of the Rodents, Mr. Lydekker says (p. 4) :— 'A survey of the collection of these animals in a good museum will show that, whether the patterns take the form of stripes or spots, the arrangement is invariably longitudinal, and " never " transverse.' Now, it is impossible to separate the Rodents from other mammals, and, as I have already said, transverse rows of spots and rosettes are not uncommon in other mammals. All that we can infer is, that in the existing Rodents no species with transverse stripes or spots are found. Perhaps this is what Mr. Lydekker meant. P. 4. ' By a splitting-up of a simple spot into a more or less complete ring of smaller ones, we have the rosette-like type of ornamentation, as exemplified in the Leopard, the Snow Leopard, and the Jaguar. In the two former, the ring encloses a uniform light area ; but in the latter the central area generally carries one or more dark spots.5 I confess I am unable to accept Mr. Lydekker's view of the origin of the rosette from a splitting-up of a simple spot, for reasons given in Part III. I am indebted to Mr. Lydekker himself for a hint of the value of those interesting ' one or more dark spots ' in the central area of the Jaguar rosette. In one of the numbers of Knowledge he described a strange Glyptodont (Dadicurus)) with a club tail, in the La Plata Museum. The holes in each armour-plate of that singular animal are, in my opinion, the equivalents of the dark spots in the interior of the Jaguar rosettes, a remarkable example of which is to be seen in the Tring Museum. i28 STUDIES IN THE EVOLUTION OF ANIMALS Then, in the beautiful illustration of the Snow Leopard in Mr. Lydek- ker's paper under discussion, we seem to follow the genesis of the stripes on the tail gradually from the rosettes on the haunch of the animal. The rosettes are carried on to the base of the tail, and insensibly, by flattening and obliteration of the enclosed area, they are converted into stripes. So that we have the choice of two modes of genesis of stripes- cither, as I have shown, from rows of rosettes, like the twin stripes of certain Tiger skins, or from single rosettes, as indicated above. P. 4. 'A further development of the ring leads to the so-called clouded type, as displayed by the Oriental Clouded Leopard, the Marbled Cat, and the American Ocelot. Here the ring becomes enlarged into a large squarish or oblong area, enclosing an area of darker hue than the general ground-colour of the fur, and bordered by a narrow black line.' In discussing the markings of the Ocelot, I have shown that their curious markings result from a fusion of many rosettes disposed in longitudinal order, and not from an enlargement of * the ring.' In the Ocelots it is a longitudinal fusion of a number of rosettes ; in the others it is a squarish patch, formed, as I think, by the fusion of a group of rosettes into one large island. Many modifications may have occurred after fusion, and in the Clouded Leopard we have perhaps a transition from this into the eventual uniformly coloured coat— a sort of breaking-up of the whole patch. The curious part is that in some Ocelots the central dark spots of the rosettes are still retained, but they become arranged in line in the centre of the longitudinal band, while the amalgamated rings form a black border to the scolloped band. P. 5. Professor Eimer, ' as the result of his investigations, laid down the following laws : — * Firstly ', the primitive type of coloration took the form of longitudinal stripes ; secondly ', these stripes broke up into spots, retaining in many cases a more or less distinct longitudinal arrangement ; thirdly, the spots again coalesced, but this time into transverse stripes. And, further, all markings disappeared, so as to produce a uniform coloration of the coat.' To this Mr. Lydekker says (p. 5) :— ' There ought, if the theory were true in its entirety, to be a considerable number of longitudinally striped species among the lowest groups of all. . . . POSTSCRIPT 129 Professor Eimer makes no distinction between light and dark markings ... nevertheless we may provisionally consider light and dark stripes and light and dark spots as respectively equivalent to one another.' I presume that by the ' lowest groups of all ' Mr. Lydekker means the mar- supials. Biologists look upon these animals as the \x\w& primitive types of mammals, and therefore the oldest. This, I should say, is a good reason for believing that they had, compared with others, a far longer time to change in, conformably with surroundings of sorts, and therefore it must be a wonder that we meet with any of them which are marked at all with either spots, stripes, or bands. Nevertheless some of the marked ones still survive ! This, in my humble opinion, is sufficient evidence that both they and the other mammals of superior organisation came from the same marked stock. P. 5. 'The fact that the markings of young Pigs take the form of longi- ' tudinal stripes, whereas in the more specialised Deer, whether young or old, they are in the shape of spots arranged in more or less well-defined lines, is, as far as it goes, a confirmation of the theory that " spots " are newer than stripes.' My own studies of this interesting question have led me to just the opposite conclusion — viz., that spots are older than stripes, and that rosettes are the oldest of all markings. Perhaps too much stress has been laid on the word specialised. Although the skeleton may be highly specialised, it does not appear to' me to follow that the exterior of the animal will march pari passu with its in- terior. Indeed we know that it does not. For the young and the adult of the Puma are both equally specialised, yet the former is spotted, while the latter is plain. It seems to me that the exterior of a mammal would be more actively influenced by its surroundings of sorts than its interior. And so it happens that we find, among so many differently specialised orders, survivals of ancient coloration, which occur in spite of the special- isation conformable with the order to which each may now belong. With regard to the longitudinal stripe down the back, several views seem to suggest themselves as to its origin : (a) It may be an extreme contraction of a broadly dark back, such as that of some Squirrels • (b) It may be a fusion of the oblong black spots which we see along the spine of many Leopards. It may persist longer, for some reason, along I 1 30 STUDIES IN THE EVOLUTION OF ANIMALS the. spine, when, on the flanks, shoulders, and hind-quarters all markings have disappeared. The total obliteration of markings we begin to notice on the hind quarters -and legs of the Quagga. Either the spinal line, or the leg stripes, or both, seem to persist when the body becomes plain. Why it should be so, if it is so, I do not know ; (c) I have tried to account for this spinal dark line, as a picture-remnant of the dorsal ligament, which, in the little Pichiciago, binds the horny carapace to the spinal line. This curious little Armadilloid mammal seems to be a survival of a transition stage between the bony-carapaced Glyptodonts and the hairy mammals, the former, as I think, having been the fathers and mothers, not only of carapaced mammals, but also of all hairy mammals • and I take it the Jaguar presents us with good evidence of all this. But after all this dorsal line may perhaps be of little importance; for any one can see, in the Tiger skins of the furriers' shops, that, in certain specimens, some of the transverse stripes merely meet at the spine, while others, after meeting, are conjointly prolonged in the direction of the tail. What is curious is this : that, in some mammals, this dorsal line is white. P. 5. 'Then again, in the ungulates we have the Zebra-Antelope, the Gnus, and the Zebras showing most strongly-marked transverse dark stripes ; but we have no dark-spotted forms in the whole order except the Giraffes ; while the only ones with dark longitudinal stripes are young Pigs. And it would thus appear that, although all the animals above mentioned are highly specialised species, these transverse stripes and dark blotches must have originated de novo quite independently of the groups in question.' I must humbly beg to differ from all this. I have shown that Horses do not unfrequently have dark, spots — even one little Donkey had them — and that, in the grey-dappled Horse, the white spots are sometimes arranged in transverse series of lines. These, by fusion, would give an alternation of white and dark stripes. The blotches of the Giraffe assimilate with the blotches of the Horse. Then the rosettes of the Zebu of this work are almost identical with those of certain dappled Horses. As the coloration both of the Giraffe and the Zebra harmonises with their surroundings, Mr. Lydekker thinks — p. 6, that, ' It is incredible that both types should have been evolved, according to a rigid rule from animals marked by dark longitudinal stripes,' POSTSCRIPT 131 That, is from \b&.priwitiix. markings of Professor Eimer's theory. Quite so,, but, as I have shown, it is not so incredible ;that both the .coloration of, the Giraffe and of the Zebra, as well as those of the ' dappled Horse and of the Zebu, should have been evolved from, in my opinion, the oldest coloration of all, viz,., the rosettes^ similar to those of the Jaguar. Mr. Lydekker in conclusion says that it is not improbable that there may be a certain substratum of truth in. Professor Eimer's theory. , : :; > ' What we may call the " longitudinal-spotted-transverse-uniform " theory of coloration, we submit that in its present guise it cannot adequately explain the whole evolution of "spots and stripes in mammals."' j • - ' - -' — -'<... - Mr. Lydekker's paper on .this .subject in KnowUdge.'is very well worth the attention of students of the coloration of mammals. It is, moreover,, accompanied by the most beautiful illustration of the Snow Leopard that I have yet seen. .Now, may I be allowed to put forth in concluding this P.S. my theory, of the whole question, as succinctly as I can— as Carlyle might have said, — the theory of a poor simple creature? The Glyptodonts, or other armoured mammals of a .similar, nature, were the originals from which all existing mammals, including marsupials, descended. .. The Jaguar, .for some reason or. other, has retained the most primitive type of coloration, due to the characters of the ancestral armour-//^/^— a sort of picturation of the carapace^ after this had been. wholly got rid of. ;A11 other spotted mammals— whether longitudinally, or transversely, or diagonally — are modifications of those of the Jaguar. Then the striped — whether longitudinal, transverse, or diagonal-— are fusions of lines of spots or of rosettes. This seems clear from the spotting of certain Cheetahs, certain Horses, and certain. Tigers with twin-stripes. The markings of the Ocelots, Clouded Leopards, and Marbled Cats area fusion and modification of groups of rosettes, either longitudinally disposed, or grouped in irregular patches. The piebalding of the Dog seems to be made up of fusions and agglomerations of spots, as may be seen in certain Dalmatian and other Dogs. Then in the self-coloured mammals, it is evident there is, for some reason, a total obliteration of all special marking, although they now and i32 STUDIES IN THE EVOLUTION OF ANIMALS again turn up as atavic marks, perhaps by some atomic disturbance of crossing in the nerve-centres. The curious point is, that white, black, and tan colours are interchangeable -why, I do not know. This can be readily seen in the Fox-Terrier. The black patches of the one are almost identical with the tan patches of the next. The black and tan colours of the one become tan and white colours of the next, and so on. Even the tan spots over the eyes have been known to change into white spots. So that it is no wonder that we see black spots or stripes in one order of mammals changing into modified white spots, or modified white stripes, in another order of mammals. The interchangeableness of these three colours, with variations in the shades of the tan, can be seen in many other mammals, both domesticated and wild. .... Lastly, when all vestiges of resetting, spotting, or striping have dis- appeared, as in self-coloured mammals, there may remain a vestige of the ancestral carapace as a whole, without any vestige of the separate plates. This I take to be the meaning of the dark colour of the dorsal and flank regions, as contrasted with the abdominal coloration, which I take to be a vestige of the ancestral unarmoured surface. The contrasted colours may be black, tan, brown or white (brown being a combination of tan and black). That curious flank band which some mammals have, clearly seen in certain Squirrels, may possibly be a vestige of the receding carapace in process of total obliteration, and the different contrasted colours may in- dicate the different ages of partially unarmoured surfaces — that is, the abdominal colour would indicate the oldest unarmoured surface, the flank band a later unarmoured surface, and the dorsal colour the latest of all. The origin of this flank band is, however, not so clear to my mind as. the other parts of this theory. I think we will find it impossible to account for every line, or band, or spot in the coloration of mammals, because the modifications in their coloration have been very great. We cannot call the whole self-coloration as the youngest of all, for there may have been selfs among .marsupials very much earlier than among other orders. Each group of mammals shpuld, I think, be studied by itself, with an eye to its descent from some sort of carapaced ancestor. It is a marvel .to. me that so much has been left to us of these hiero- glyphics in which, ancestral characters had been written, and that they POSTSCRIPT 133 have been so stamped in the nerve-centres that even time has not succeeded in wholly defacing them ! It is a marvel to me also that marsupials, being the oldest mammals, have anything left on their exterior to give any indication of their descent from, as I think, the common stock of armoured mammals ! Of this there cannot be much doubt. Armoured vertebrates — Fishes, Saurians, Chelonians, Glyptodonts, etc., formed, at one time of the earth's history, a vast portion of its inhabitants. In the Royal Natural History, vol. iii. p. 64, indication is given of the existence in former times of some sort of armoured Dolphins. Under extinct Cetacean-like animals — Zeuglodonts, it says, ' So far as they can be determined, the general characters of these Zeuglodonts are such as we should expect to find in an ancestral group of Cetaceans ; but it is remarkable that the body appears to have been protected by an armour of bony plates.' (!) FURTHER EVIDENCE IN SUPPORT OF THE THEORY THAT EXISTING MAMMALS DESCENDED FROM CARAPACED ANCESTORS ' Nothing impresses the stamp of truth upon an hypothesis more than the fact that its light renders intelligible not only those facts for the explanation of which it has been framed, but also other and more distantly related groups of phenomena.' Professor WEISMANN, On Heredity, p. 336. PART IV FURTHER EVIDENCE IN SUPPORT OF THE THEORY THAT EXISTING MAMMALS DESCENDED FROM CARAPACED ANCESTORS THERE is yet another important feature in the coloration of animals which, if I have rightly interpreted it, will further support the theory I have been advocating in the foregoing pages — viz., that the markings of Leopards, Horses, Zebus, Giraffes, etc., etc., are due to the plate-armour of remote ancestors. In these pages, however, I shall deal with mammals which may have no vestige of ancestral resetting, but only a great contrast of surface coloration. It has been maintained by some that the backs of certain animals are darker than their abdominal surfaces, because their backs are more exposed to light. I do not know whether this is true of all fishes. Recent experi- ments would tend to show that light, as an electric agent, has some- thing to do with the darkening of the skin of fishes. I do know, however, that this is not true of many mammals. A few examples will clear this misconception. The family of the Badgers and allied species affords a number of examples of black under parts, and either white or light-coloured upper parts ; and most of these are nocturnal animals, so that we cannot consider their contrasts of coloration as having had much to do with a natural selection origin, by way of warning colours. 138 STUDIES IN THE EVOLUTION OF ANIMALS Then in the Natural History Museum we find that Propithecus coquereli has the front of all four legs brown, and the posterior of the legs and back of the body wholly white ; that P. coronatus is brown on the abdomen and white on the back ; that P. Edwardsii is dark brown everywhere except \the posterior half of the back, which is white ; that Varesia varia is black on the abdomen and front of legs, and yellow-brown on the back. (Further, the Egyptian ^orille or the parti-coloured Weasel has a white back, striped longitudinally with intense black, and its ventral surfaces and legs are black. These might be sufficient to prove that light cannot be the cause of this difference in the colorations of the upper and lower surfaces of mammals. But if, in addition, we take that large class of mammals, which have a dark back and a lighter-coloured abdo- men, we shall find that, in many cases, — such as in the Gazelles, the Black Buck of India, the black-backed Jackal of S. Africa, etc.,— there is a distinct and very sharp line of demarcation, along the flanks, between the two colours. This sharp line of demarcation alone would be wholly opposed to the theory under review, for there is no known property of light by which such a result could be produced on the flanks of these animals. Moreover, the front aspect of the legs of these animals is in most cases darker than the hind aspect ; and we cannot suppose that the sun rays always beat upon the legs from the front. It is obvious that in walking away from the sun the hind aspect would be more lighted ! The same objec- tion can be brought against this view, in the case of those Antelopes which have patches of white either in front or behind, and which Dr. Wallace would call * recognition marks.' Then what shall we say of all those Antelopes and Deer which, on a dark ground, are either spotted or striped with white ? Why have these white marks not been obliterated by the light? MAMMALS WITH CONTRASTED COLOURS 139 What I have said is enough, I think, to prove that this light theory is wholly untenable, at least as far as mammals are con- cerned.1 The reader might however say, Have you any other theory to substitute for the light theory ? Yes, I have, and it is this : I have endeavoured to show that the spots and stripes of mammals are in many cases pictures of ancestral armour-plates, modified subsequently in hundreds of ways in some, or wholly obliterated in others. Well, the same theory of descent from armour-plated ancestry will explain why there is on the flank of many animals that sharp line of demarcation between the dorsal and the ventral colouring. o That sharp longitudinal line indicates the margin of the ancestral carapace, as we see it in the Armadillo, the Glyptodon, the Pango- lin, and others. Curiously enough, the little Armadillo of Argentina (jCklainy* dophorus tnmcatus] has its armadilloid armour sharply truncated posteriorly, and its rump is patched up by a differently plated perpendicular shield. This curious appendage, according to my view, might perhaps account for that white patch which so many ruminants have behind, the line of demarcation between the dark 1 I am aware that in the cases of peaches, apples, pears, etc., light colours their cheeks, and I have seen a peach, partly shaded by one leaf, not acquire colour under the leaf. But I am also aware that round the stone of certain peaches there is the same red colour we see on their cheeks, while the intermediate thickness (sarcocarp) is either white or yellow, and this central redness could not be produced by light in its ordinary sense. Then there are the purple aubergines, which acquire their intense colour also on the shaded sides. And I have been informed by a noted horticulturist that he has seen the black Hamboro' grape beautifully coloured when the roof of the house was almost wholly shaded by the leaves. He also told me- that he has seen the red seakale and the red rhubarb grown in total darkness, and the tips of their leaves nevertheless always acquire a red tinge. Moreover, we do not see the sweet-water grape colour, although grown outside and fully exposed to light. I think if we substitute electricity for light, acting on certain chemical ingredients, we may perhaps be nearer the right explanation. 140 STUDIES IN THE EVOLUTION OF ANIMALS back and light-coloured rump being very sharp. It might mean that the ancestors of those ruminants had that rump shield, and that it was got rid of earlier than the dorsal carapace, and thus a sharp contrast of coloration was inherited in consequence. There is an alternative supposition, for in some Armadillos we find that the carapace stops short of the tail, and leaves a bare space between the tail and posterior margin of the carapace, and this fact may remain recorded in the ruminants and others that have a white patch behind. It would seem to mean only a continuation of the unarmoured ventral surface. Among the animals that are so patched behind are the .Siberian Roebuck (Capreolus pygargus), Wapiti Deer (Cerviis Canadensis), Pronghorn (Antilocapra Americana], Bonte-bok (Dainalis pygargd], Sable Antelope (Hippotragus niger\ Scemmer- ing's Antelope, and several others. It may be quite true that animals now make use of these white patches as ' danger marks,' and ' recognition marks,' but their origin is I think explained by the abruptly truncated dorsal armour of some ancestral form. In the 'Pichiciago' Armadillo of Argentina, the vacant space is covered by an additional rump-shield, but in others it might be absent, as we indeed see it in several other varieties of Armadillo. In this connection I would mention that in the Natural History Museum there is an interesting and very suggestive preparation of this little Armadillo. It has no calcareous or bony carapace— but only the epidermic horny shell of one. Under this horny shell there is a hairy coat as in other animals. The curious part is, that the horny shell is attached to the true skin by means of a thin ligament all along the spine. This latter feature may perhaps give us a clew to the interpretation of that spinal dark or white 1 1 The Kerry breed of cattle are black, with a white streak down the back, and sometimes another along the belly. — (Roy. Nat. Hist.) vol. ii. p. 168. ) stripe which so many animals present. This may perhaps be a vestige of the attachment of this dorsal ligament in some ancestral form, during the transition between the stage of plate-armour and the stage of hair-covering. The spinal dark or white stripe of certain animals might indicate that the general colour of the surface altered earlier than the spinal surface, and therefore had time to become contrasted in colour. I will not however press this point, should the reader think it preposterous. It may be looked upon as a mere suggestion. My contention is that the differently coloured dorsal and flank regions of certain animals, as contrasted with the coloration of the abdominal surface, is a vestige of the ancestral armoured carapace, the sharp line on the flank indicating its margin, while the white, or differently coloured abdomen, as in the Badger, the Egyptian Zorille, and others, would indicate the ?/^armoured ventral surface of the ancestral forms. The origin of the white patch behind would fit into this theory, and would indicate the truncated posterior margin of some ancestral carapace. In studying the Armadillo, we find that the abdomen, legs, and under surface of the head and the throat are almost denuded of scales, and much more so are the hind-legs of Kappler's Armadillo. Then in some Pangolins, we also find that the under surface of the head, the throat, the inner aspect of the legs, and the abdomen, are devoid of scales. It can readily be understood that scales on those parts would prevent the animal from rolling himself up for defence. The loss of scales in those parts, while it gave him greater freedom of move- ment, enabled him to roll himself up, and protect those unarmoured surfaces, just as a Hedgehog would do. Now in the Black Buck (Antilope cervicapra), instead of armoured and unarmoured surfaces, we find simply contrasts of 142 STUDIES IN THE EVOLUTION OF ANIMALS coloration in homologous surfaces, viz., the forehead and nose, the body and outer aspect of the legs, and upper surface of the tail are black, and the under surfaces, corresponding with the unarmoured surfaces of the Pangolin, are white. This, in my judgment, means that the ancestor of the Black Buck lost its armour on what are now white surfaces long before it lost it on what are now dark surfaces, so that those had the opportunity of having their pigment modified,1 and so becoming contrasted by the time the descend- ants wholly lost their armour. And the only thing now left to tell the tale of ancestral armour in many animals is solely this contrast of coloration, which in certain animals still remains, as a survival of a feature which in remote times may probably have been general. In the Horse, through innumerable selections, this contrast of upper and lower surfaces has been mostly extinguished, although Horses of a brownish colour are often met with which have the lower surface much lighter than the upper. But it is in the coster- monger's Donkey that a great contrast is visible between the dark back and flanks and white abdomen. In black-and-tan Dogs the contrast between the two surfaces is very marked ; and there are variations in which the contrasted colours of the Dog are tan and ivhite> or black and white. It is not improbable that as time goes on all traces of contrast derived from armoured and unarmoured surfaces may disappear, unless maintained for special purposes, either by natural or artificial selection, or unless reversions to ancestral colourings occur. Among domestic animals this obliteration has already largely occurred. In wild animals we see this obliteration in the Lion, the Puma, the Hare, certain Deer,2 and others. 1 In the domestic Dog we see how readily the hair pigment is modified, even in one generation, from black to tan, and from black or tan to white. 2 The young of the Wapiti Deer is spotted, while the adult has no trace of spots. — Cervus Canadensis, Science and Art Museum, Edinburgh. MAMMALS WITH CONTRASTED COLOURS 143 Some Horses, as I said, show a light-coloured abdomen and inner aspect of legs, but this is not common. Usually the lighter colour is very partial, and nothing like what it is in the domestic Ass, or the Black Buck. See Grevy's Zebra, fig. 52. Dr. Wallace, I think, is partly right and partly wrong, when he says that the Rabbit has acquired the white colour on the under- side of its tail by natural selection, so that it might use it as a danger-signal. In my judgment it got the white colour by inheritance from a remote ancestral nnarmoured surface, the white colour being a vestige of that ; while it may have acquired the habit of turning up its tail, and showing the white banner, through natural selection. We know, too, that other animals, under the excitement of fear or anger, cock up their tail, so that it is no wonder the Rabbit should do the same. The survival of those that could perform this social function would follow as a consequence. The Rabbit is a defenceless and timid animal. For its safety it has to depend on its large ears, in addition to the faculty of running into holes when its ears declare that possible enemies are about ; and turning up its white surfaced tail, when running home in the uncertain light of the dusk, may be a very useful way of showing its associates which way the holes lie. This theory I am advocating will also explain why the front or exterior aspects of all the legs of many animals are so often, especially in Gazelles, differently coloured from the posterior or inner aspects. Naturally the front and outer aspects of the limbs, which received the brunt of the enemy's attacks, would have been differently armoured from the posterior and inner aspects. This is the state of things in certain Pangolins, for instance. Something may perhaps also be due to the likelihood of there being only a limited amount of armour-material in the blood, and only those parts which urgently needed protection could be supplied: with it. 144 STUDIES IN THE EVOLUTION OF ANIMALS The reader should understand that, as in the case of spotting, innumerable modifications have occurred, through which, in many cases, the sharp line of demarcation, between the ancestral armoured and unarmoured surfaces, has been toned down into a graduated passage from the dark dorsal to the light ventral colouring. This theory, however, should not be driven too far, for it will not account for every single hair that may be differently pig- mented ; but I think it will account for the general colouring and spotting more satisfactorily than the older light theory. Then human selection of animals under domestication, and natural selection of animals in a wild state, will account for the vast number of modifications we see in the coloration of animals. I would ask the reader to glance at Fig. 72. Nothing, to my mind, can be plainer than, the tale its coloration and spotting suggest regarding its descent, in spite of the great modification its legs and its digestive apparatus have undergone to fit it for surroundings totally different from those of its ancestors. Its partially edentate upper jaw seems to tell a similar story. This Deer would seem to say, ' My spots are the vestiges of ancestral armour-plating, and that fringe you see on my flank is the vestige of the fringe of differently-shaped plates which form the margin ot the Glyptodon's carapace.' No one could look at the picture of Mellivora Indica in Mr. Blanford's Mammalia of India (Fig. 46), without seeing in its well- defined grey back a strong resemblance to a carapace ; and the picture-carapace of Putorius sarmaticus (Fig. 41), is still more striking, as its vestigial carapace still retains the vestigial spotting of its ancestral bone-rosettes. Even the sheep in the London parks seem to tell you, * My fleece is the substitute of my ancestor's carapace. In those days, my ancestor's face, ears, hands, and feet, were unarmoured, and now MAMMALS WITH CONTRASTED COLOURS '45 the hair there is short, and of a different colour from my fleece-^- that is either white, brown, or black. My relative the Wolf, who in former days was my enemy, is now my friend and caretaker. He FIG. 72. — A Spotted Deer, frorn a photograph, C. R. 1393., too in his "fleece" shows distinct evidence of our common ancestor's carapace.' If we turn to the White-backed Skunk, a good picture of which is given in the Royal Natural History, vol. ii. p; 76, we find K 146 STUDIES IN THE EVOLUTION OF ANIMALS similar contrasts. The peculiarity of its contrasted coloration, the writer says, is regarded as belonging to the class of so-called * warning colours.' Mr. Poulton observes that such warning colours would seem ' to benefit the would-be enemies rather than the con- spicuous forms themselves But the conspicuous animal is greatly benefited by its warning colours. If it resembled its surroundings, like the members of the other class, it would be liable to a great deal of accidental or experimental tasting, and there would be nothing about it to impress the memory of an enemy, and thus to prevent the continual destruction of individuals. The object of warning colours is to assist the education of enemies, enabling them to easily learn and remember the animals which are to be avoided.' There cannot be much doubt that an animal possessed of such a coloration and character, and also of such ' nauseous and irritat- ing artillery/ as has been described, would be avoided, when its means of defence had become known. But we cannot in any way admit that it is its * stinking secretion ' which has caused this ' con- trast of coloration.' The animal itself no doubt has learnt that it is not attacked, and this accounts for its ' indifference to the pres- ence of other creatures ' which is said to be ( one of the most striking characteristics of this animal and its congeners.' Therefore the contrast of coloration between the white upper surface and crown, and the black under surface and face, must be attributable to some other cause. When the plan of coloration of this White-backed Skunk became once established by hereditary influences, it began to change like everything else, unless it were maintained by natural selection, through the action of the surroundings, as has happened in the case of the Leopards ; and this change we see, further on, in a brother Skunk. MAMMALS WITH CONTRASTED COLOURS 147 We can understand that an animal something like a Pangolin, when it got rid of its armour, and when hair was substituted for it, — as indeed we see has occurred in the little Pichiciago — the hair covering remained under the same nervous influences which by habit its ancestors possessed when they had back-armour ; and in all probability the contrast of coloration of the hair of some of the descendants is caused by the same nervous influence. As a matter of fact we find that another animal, which we might say is a brother of the Skunk we have been discussing, has not this conspicuous warning coloration, although it possesses a similar ' nauseous artillery.' This Common Skunk (so different from the White-backed Skunk) has a black or blackish body, and ' although there is a great amount of individual variation, the white markings usually take the form of a streak' on the forehead, a spot on the neck, and two stripes running down the back. ... In some cases the white stripes do not extend beyond the neck, so that the back is entirely black.' In the Common Skunk, it would seem, the change of colour has gone on to such an extent as to leave nothing but mere vestiges of its ancestral carapace-like white back ; and therefore the theory of warning colours having been caused by ' mephitic ' influences evaporates. It can be readily understood that possible enemies who may come within the sphere of its effluvium don't require to see any warning colours, they can smell the animal from a long distance, and would naturally leave a good space between him and them ; so that the ' mephitic ' warning may continue without the so-called warning colours. One can hardly contemplate the Black-backed Jackal of South Africa in the Zoological Gardens and not think its sharply defined back related to an ancestral carapace. The Dingo of Australia has 148 STUDIES IN THE EVOLUTION OF ANIMALS similar markings, but the black on its back is less marked. Very probably, either the one or the other has given our black and tan domestic Dogs their distinctive coloration, which, in some varieties, becomes tan and white. These and many others, in my opinion, owe that particular feature to an ancestral carapace, although the separate spots — vestiges of bone-rosettes — may have wholly dis- appeared ; they still persist, however, in the Dalmatian breed of Dogs. I have seen a curiously marked Toy Terrier of the black-and-tan breed. Its back was grey and sharply defined like that of a Badger, and it was blotched and striped with black. And in the Natural History Museum there is a tiny Cheetah from the Cape which is also curiously marked. Its back is grey like that of a Badger, and the other parts are spotted. It is impossible to contemplate these reversions without thinking that they must have a deeper meaning than that of being simply accidental. At the risk of wearying the reader with repetitions, let us now try to recapitulate briefly the whole process, and endeavour to form a clear conception of how these phenomena could have been brought about. First, we must assume that natural selection, as indeed is admitted by modern biologists, must have had a great deal to do with evolving, from previous modes of armour, with the help of congenital variations, the forms of carapaces we see in the Glypto- donts and Armadillos with plate-rosettes. The congenital ^varia- tions in the plates of carapaces were presumably brought about by changes in the central nerve-action. This action we as yet do not understand, any more than we understand how thought is evolved from it. There can be no doubt however that in the higher animals it is all-important, and governs everything. This original nerve-action, however caused, by which a rosetted MAMMALS WITH CONTRASTED COLOURS ,149 carapace was elaborated, became confirmed by ages of usefulness. In other words, the nerve-centres acquired the habit of acting that way. Then when, from whatever cause, the calcareous matter of the exoskeleton disappeared, the nerve-centres continued that same action, which resulted in pigment pictures of the ancestral plate- rosettes on the, supple and elastic unarmoured skin. This is not all, for the margin of the carapace was also pictured by contrast of colour between the upper (ancestrally armoured) and the lower (unarmoured) surfaces ; the margin remaining pictured even when all traces of resetting had disappeared. Then innumerable further modifications in the atomic constitu- tion of the nerve-centres, in which natural selection no doubt has played a great part, have resulted in all the varied colorations of mammals we see. Of course it is impossible to say what atomic changes in the nerve-centres produce a dark back and a light abdomen in some, or a light back and dark abdomen in others, any more than it is possible to make out why one animal turns out albino, and another melanoid, or why in one very dark grey Horse, with only few vestiges of spots, its mane and tail wereflure white. Some might perhaps fancy that they account for changes in coloration by saying, ' Oh ! that is an albino', or ' that is a case of melanoid variation.' But this in no way explains its cause any more than if one said it is a ' whitino,' or a ' blackino ' ! We are at present wholly unable to say why, in a litter of black-and-tan puppies, one comes out wholly tan, or tan and white ; or why, in a litter of tan puppies, one comes out wholly black, or wholly white. All we can say is that these phenomena do occur. This we may say ; in the Jaguar these changes of colour occur in the components of the rosettes themselves. What I conjecture 150 STUDIES IN THE EVOLUTION OF ANIMALS was ancestrally a big central plate is now in the rosette of the Jaguar a brown patch ; and what were the encircling platelets are now black spots^ or a fusion of them forming a black ring, the whole rosette being of a different colour from the general fawn colour of the inter-rosette spaces. These three distinct colorations, well marked in the Ocelots, suggest atomic localised differences in the nerve-centres of which at present we know nothing. Why in the Cats the spots are black, and in the Deer they are white, I am unable to say. I find it also impossible to determine whether the grey dappled Horse is an albinoid variation of the brown dappled Horse, or the latter is a melanoid variation of the former. I must leave such questions for others to answer who may know more about the matter than I do. All I am here concerned with is, that there is in many animals a sharp line of demarcation between the colouring of the back and that of the abdomen, and this I attribute to ancestral differences of armoured and unarmoured surfaces. No one who is imbued with the principle of evolution can contemplate the skin of the Jaguar in Fig. 4 without saying, Yes ; the whole thing is a picture of armour-plating. This is not, however, all, for that skin, in the different mode of resetting be- tween the dorsal and the ventral surfaces, and in the difference of general coloration between the upper and lower parts, gives also evidence, at least to my mind, that the lower lost their armour before the upper parts. This theory does not attempt to account for the variations of nerve-centres. Those must be relegated to congenital causes we do not yet sufficiently understand, and perhaps to the action of the environment. In another part I shall endeavour to show that armoured mammals must have been originally and ancestrally armoured all MAMMALS WITH CONTRASTED COLOURS 151 over, that is, dorsally and ventrally, like the extinct Ganoids and existing Crocodiles ; and that in dispensing with their armour they first lost it on their ventral aspect, and second, and much later, on their dorsal aspect also. . At the risk of seeming tedious, I repeat that this, in my opinion, is the reason why so many mammals present a distinct contrast between the coloration of their dorsal and ventral aspects with a sharp line of demarcation between the two. Of course later on there may have been a fusion of the two distinct colorations, and all traces of demarcation wholly obliterated. Examples of this obliteration are seen every day among Horses, Dogs, etc. RESEARCHES AND DISCUSSIONS TO , CONNECT, MORE SURELY, ARMOUR- PLATING WITH SKIN-PICTURING ' We can only say generally, with Darwin, that selection works by the accumulation of very slight variations, and conclude from this that these '•'•slight variations" must possess selection-value. To determine accurately the degree of this selection-value in individual cases is, however, as yet impossible.' The All- sufficiency of Natural Selection, by Professor AUG. WEISMANN, Contemporary Review, September 1893, p. 322. PART V RESEARCHES AND DISCUSSIONS TO CONNECT, MORE SURELY, ARMOUR-PLATING WITH SKIN-PICTURING Is there any tangible evidence to prove that skin-spotting is often the result of ancestral armour-plating ? To answer this question we have to take a wider view of vertebrate animals. There is a great number of existing animals, which now have only a partial and scattered armour, evidently a mere vestige of a more complete and closer fitting ancestral armour. The partial or complete disappearance of the bony plates of the exoskeleton, from whatever cause, not unfrequently leaves spots or other marks on the skin, in their stead, as records, so to speak, of what had gone before. I shall give only a few instances from fishes, which can be seen in the Natural History Museum and in other records. A Ray-fish with a whip tail, labelled Urogymnus asperrimns, has a broad carapace, from head to tail, studded with closely-set plates of two sizes, viz., large stellar and spinose plates, encircled by minute tubercular platelets, the tail being wholly encased in similar plates. Then an allied Ray-fish (a sting ray) from the Australian waters, Trygon tuberculata, has only scattered spinose plates on its head and sides, and a complete spinal line of similar plates, running into the tail, which is also covered with spinose plates. Of another allied species, also from the Australian waters, 156 STUDIES IN THE EVOLUTION OF ANIMALS Trygon brevicaudata^ there are two specimens, (a) with a smooth skin, seven plates on dorsum of tail, and minute scattered plates on other parts of the tail ; (ft) also with a smooth skin, but with several spots on both sides, and only eleven plates on dorsum of tail besides other minute tail-plates. This series of fishes is very instructive, and there is no good reason to doubt that in the latter the spots are partial vestiges of the more complete armour of Urogymnus asperrimus. The back- armour and tail-armour of the latter would lead us on, in the course of ages, to the huge carapace and curious tail-armour of the Glyptodonts. There are many spotted Sharks, and the spinous Shark (Echin- orhinus spinosus Gmeliri)1 is dotted with spinous plates, some isolated, others confluent in groups. It seems probable that these are only vestiges of an ancestral and more complete carapace. Then there is another fish in the Natural History Museum which, in this connection, is very instructive. It is the Serranus gigas of Muscat. It is a large scaly fish in one of the middle cases. The horny scales of fishes can only be considered as a modification of the bony armour-plates, like those of the bony Pike and extinct Ganoids. Well, the large body scales of this Serranus have each a black dab. On the cheeks of the fish 2 the scales become thinner and thinner, and almost amalgamated with the skin, each scale still retaining the black dab. Then on the lips of the fish the scales disappear, but the black dabs or spots remain. Of course the spots in this case are not exactly identical in genesis with those of the Jaguar skin, unless we suppose that the Glyptodontoid ancestors of the latter, besides their bony plates, had also a corresponding set of horny plates, like those of Arma- dillos, and spotted analogously to the spotting and marking of the 1 Science and Art Museum, Edinburgh. - Technical terms are here unimportant. ARMOUR-PLATING AND SKIN PICTURES carapace of certain land Tortoises. The black dabs on the scales of Serranus are as distinct from the skin as the ocelli in the Peacock's feathers, yet where the scales are suppressed, the black dabs remain. A striking example of stamps remaining on the skin after plate-armour has disappeared is to be seen in Serranus hexagonatus} All over the surface it has hexagonal markings independent of the scales. These markings forcibly recall the hexagonal armour-plates of the Ostracions. Then Serranus Merrahas the marks passing into confluent blotches, while vS. Sonneratii, PL vii., Fig. i, has similar hexagonal marks, but only on the fore part of the body and head, being totally obliter- ated on the rest of the body. The singular markings of these species of Serranus are quite paralleled by the markings of the fully dappled and the partially dappled Horses. Then in the York Museum I found an Ostracion, with plates shown in Fig. 66 (b\ They were marked with six dark spots. Well, this fish on its tail had no plates, but only the black spots. Then if we look at the back of the Dinosaur, with rows of detached plates along its spine, as restored by Mr. Hutchinson (Fig. 73), we shall see that if the plates disappeared, rows of spots might be the result, like those along the back of certain Leopards. .' I know that there are puzzlers among the markings of fishes, such as the Leopard markings of Trygon uarnak, and the Giraffe 1 Fishes of India, by Francis Day, Pi. ii., Part. i. Fig. 3. FIG. 73. — Back of Scelido- saurus Harrison i, as re- stored in Hulc-hinson's Extinct Monsters, pi. 8. 158 STUDIES IN THE EVOLUTION OF ANIMALS markings of Murcena tessellata, and others, but one cannot be expected to tackle the whole of creation at once, and the interest- ing spottings and markings of fishes must be left for some future investigation. By that time experimenters on the spotting of lower animals may perhaps be able to give us something definite as to their cause. This I know, that, even in plants, hairs or spines are often accompanied at their base with spots, and when the hairs disappear the spots remain. Here are a few instances : Begonia argenteo- guttata has spotted leaves, and each spot has a hair, which is the plant armour, while in Begonia Rex the leaves are piebald, that is, a number of spots have become confluent Some varieties of this remain haired all over, while others have lost their hairs. Then in Begonia maculata the spots remain, but the hairs are suppressed. The deposition of dermal plates in animals undoubtedly depended on heredity, the action of nerve-centres, and an available supply of lime-salts, so that, as I have stated further on, when the plates ceased to be developed, from a deficiency of lime-salts in the blood, the nerve-centres, still continuing their influence, would have brought about changes in the pigmentation, which now, in certain cases, picture the plates themselves. The main evidence, however, of the Jaguar and Leopard having descended from plate-armoured ancestors is in the resem- blance of their pigment-rosettes to the plate-rosettes of those extinct mammals ; x the same nerve-action which gave rise to bone-rosettes was certainly equal to produce pigment- rosettes, from which the hairs grow. That hairs will often grow as soon as there is a part of the skin free from plates is sufficiently proved by the Hairy Armadillo, and some of its congeners. 1 In the Tring Museum, as already mentioned, there is a Jaguar which, on the flanks, has very large polygonal rosettes with many (from one to six) spots in the enclosed space. ARMOUR-PLATING AND SKIN PICTURES 159 Indeed, Professor Parker1 has shown that in the embryo of the Pangolin the scales are nothing but matted hairs, and the inter- vening spaces are also covered with hairs, so that the substitute for bone and horn armour, in mammals, seems to be hair or wool. The description of spotting phenomena in animals by words is a feeble thing compared with illustrations by photography, but to photograph every modification would require a library, and not one book. The general colouring of a mammal is of little importance, because we know that this varies very much ; but if the markings are constant, though the general colour changes, we must infer that they have a different and a deeper meaning than the general colouring. In Pigeons, the wing-bars very often remain, although the general colouring may vary ad infinitum. There are grey and also cream-coloured Pigeons with brown bars, and blue Pigeons with black bars, and so forth. And Dr. Wallace mentions2 that in the skirts of the forests on the Amazon, and in the larger ' ilhas,' both the black and spotted Jaguars are often found. By black, I presume he means the melanoid variety with distinct rosettes, which can readily be distinguished in certain lights. We see a similar persistence of markings in the Snow Leopard, although the ground colour has changed to white.3 From all this persistence of markings, as something distinct from the general colour, I would infer that the markings have a deeper meaning than the general colour, and the meaning I would attribute to these persistent markings in mammals is that they have been inherited from much more remote ancestors than those 1 Mammalian Descent. 2 Travels on the Amazon, p. 63. 3 In the Tring Museum I saw two varieties of Snow Leopards ; (a) with ocellated rosettes, and (b) with a large number of the rosettes solid, especially on the shoulders, haunches, and lower flanks. i6o STUDIES IN THE EVOLUTION OF ANIMALS which have given them their general colour, that is, from an ancestry in which" plate-armour had been established for ages. •..'_ I would repeat that the' spotting is the important feature, and not the colour '"of the spotting — for we see in the Cheetah, black spots on a light ground, and in the Deer, white spots on a dark ground, and in the Kerry Cattle we see a white spinal line, instead of the ordinary dark one. The reader might say — Is it reasonable to suppose that an armour-plate should leave an impression after the bony plate had totally disappeared, and should continue to be pictured in the descendants for innumerable generations? It does seem strange that this should be so, but impressions are left from far more .transient causes than the carrying of bony plates on one's skin for perhaps millions of years. Mr. W. B. Croft, in a communication to the Physical Society, x has shown that impressions of coins can somehow be left on a clean glass, invisible at first, but made visible by breathing on the glass ; also that an impression of a paper, printed only on one side, can be invisibly taken by pressing it between two plates of glass. The printing can be brought out by breathing on the glass which was opposed to the printing. What is more curious is that a similar print-impression is given to the glass which does not face the printed surface. This latter impression can also be brought out by breathing over the glass surface, and it is evidently produced through the paper. Presumably light may have some- thing to do° with these -impressions. But if so slight and temporary an influence can leave an impression on the. glass, what wonder would it be if the armour-plating, carried for who knows how many ages, should have so modified the skin, and its nerve-centres, as to transmit plzte-pictures, even when the calcareous plates had totally disappeared ? 1 Reproduced in Year Book of Science for 1892, p. 16. ARMOUR-PLATING AND SKIN PICTURES 161 My object in all this discussion has been to endeavour to discover why the Tiger and Zebra are striped, why the Jaguar and the Leopard are resetted, and the Deer and Horse dappled, and why there are so many animals of different classes which have ringed tails. The skeletons of all these animals inform us that they are all related structurally, and therefore they must have come from some common ancestral source, if not from the same pair of parents, certainly from the same class of parents. In another place I have shown that the same pattern of armour- plates can be traced, through the Crocodile to the Sturgeon, and perhaps also much lower down in the scale of life. Professor Huxley x says : * If the doctrine of evolution be true, it follows that, however diverse the different groups of animals and of plants may be, they must all, at one time or other, have been connected by gradational forms ; so that, from the highest animals, whatever they may be, down to the lowest speck of protoplasmic matter in which life can be manifested, a series of gradations leading from one end of the series to the other, either exists, or has existed/ Professor Alleyne Nicholson in his Swiney Lectures of 1893 repeated the same thing. He told us that all forms of life on this earth originated from pelagic low forms like those still in existence in the oceans. But what is there to show that in the picture-plating of the Jaguar the enclosed space is homologous with the larger middle bone-plates of the Sturgeon, the Crocodile, the Glyptodon, etc. ? There is nothing to show this beyond the difference tn- colour of the enclosed space in the Jaguar rosettes as compared with the general ground colour of the animal's skin. I have endeavoured to empha- sise this difference of colour in No. 9, Fig. 59. The shaded space 1 ' Science and Hebrew Tradition ' — Lectures on Evolution, p. 89. L 1 62 STUDIES IN THE EVOLUTION OF ANIMALS between the rosette blotches indicates the enclosed space, but the Jaguar skin of Fig. 4 sufficiently shows that the enclosed spaces of the rosettes are of a different and deeper shade.1 In some Ocelots the enclosed space is quite brown. This difference of colour would certainly indicate that in the nerve-centres there was some differ- ence, although of an atomic character, in the cells which regulate the colour of the inside and of the outside of the rosettes. In all probability the atomic difference is of the same nature as that which caused a large plate to be deposited in the centre of the armour-rosette and a ring of small ones outside it. What we have to note is that there is a difference between the inside and outside of the Jaguar and Ocelot rosettes. Why this is so we do not know, any more than we know why one Horse is dun, another bay, a third brown or black ; why a dun, a bay, a dark grey, and even a black Horse sometimes has a pure white mane and tail, and so forth. To sum up, in the existing Jaguar coloration we have the following elements, no doubt much modified from those of the ancestral Jaguar :— (a) We have the general ground colour of a rich tan between the rosettes ; (3) We have the spots more or less fused, which make up the polygonal rings of the larger rosettes ; (c) We have the enclosed space, which is often of a darker hue than that of the ground spaces ; (d) We have those curious central black spots. Now I have elsewhere mentioned that tan colour is interchange- able with either white or black, and so we have the general colour changed into either brown or black in the black Jaguar. 1 In the photograph this is decidedly shown, but in the illustration the difference of colour is not so clear. ARMOUR-PLATING AND SKIN PICTURES 163 The enclosed space alone may change into black, and so obliter- ate the space and turn the ocellated rosette into a solid rosette, as we see it in the Serval (Fig. 17) ; or the rosette may be so con- tracted as to obliterate only the middle spots, as in most Leopards. Finally, we may have the whole surface changed either into a jet black, obliterating all traces of rosettes, as in the black Leopard of Johore, and the jet black domestic Cat ; or the surface may be changed into a uniform rich isabelline colour, as in the adult Puma ; or the ground colour inside and outside the rosettes may change to white, as in the Snow Leopard. A further obliteration of all colour produces the albino domestic Cat. In all this theorising about the descent of resetted, spotted, and striped animals from carapaced ancestors, it should be distinctly understood that I do not in the least maintain that the Jaguar or Leopard descended from this particular Glyptodon^ or that particular Dcedicurus. What I mean is that the Jaguar and Leopard bear on their skins the stamp of having descended from a carapaced ancestor, which had bony rosettes something like those of a Glyp- todont. How many bone-rosettes, and of what exact shape they were, in this conjectural ancestor, I am not in a position to say. In this discussion the whole evidence is circumstantial, for no one has ever seen the passage of a Glyptodon's carapace into the rosettes of the Jaguar. One would indeed require to have lived a good bit of time to witness a Glyptodon changing into a Jaguar, considering that Cuvier found no appreciable difference between the skeletons of the ancient mummified animals of Egypt and their representatives which lived 3000 or 4000 years later.1 In these and similar investigations circumstantial evidence is the only kind of evidence obtainable, and it is very valuable. The connecting gradations must be filled up by the imagination. 1 ' Science and Hebrew Tradition ' — Lecttires on Evolution, p. 77. PROBABLE MEANING OF SOME INTEREST- ING FEATURES IN HORSES AND OTHER MAMMALS ' Positively, the principle may be expressed, in matters of the intellect, Follow your reason, as far as it will take you, without regard to any other consideration. And negatively, in matters of the intellect, Do not pretend that conclusions are certain, which are not demonstrated, or demonstrable.' From Professor HUXLEY'S Definition of Agnosticism. PART VI PROBABLE MEANING OF SOME INTERESTING FEATURES IN HORSES AND OTHER MAMMALS BESIDES the dappling which I have tried to account for, Horses have certain other marks which are very common indeed, and which are more conspicuous in self-coloured Horses, such as bays, browns, blacks, etc. For instance, Horses very commonly have what is called a white ' blaze ' all over the front of the face down to the mouth ; or a simple white star on the forehead, which varies between a mere white speck and a white patch. Then there are intermediate stages as shown in Fig. 74. Some- times the * blaze ' is interrupted, a white patch being on the fore- head, and another on the nose, and so on. Finally every trace of the white blaze may be obliterated, and the whole face is of the same colour as the body. Frequently, however, in dark and dun- coloured horses the blaze is black, and in dark grey horses it is of a sooty Tgrey, more or less interrupted, on a lighter ground. Now, is there any way of accounting for this feature, so common in the domestic Horse ? One day, in Piccadilly, I saw standing a dark grey cab Horse. On its forehead it had three pairs of faint radiating stripes of a grey colour on a white ground — as shown in Fig. 75 (a). It struck me that these might be vestiges of the Zebra face-marks. There happened at the time to be a stuffed specimen i68 STUDIES IN THE EVOLUTION OF ANIMALS of Burchell's Zebra in Rowland Ward's window ; so I went over to look at it, and found that the marks on this Horse's face corre- sponded to three pairs of similarly radiating stripes on the Zebra face, as shown in Fig. 75 (£). In studying this curious feature further, I came to the con- clusion that the dark blaze on the dark grey Horse, and on some bay and dun-coloured Horses, was a more or less complete fusion of the stripes we see on the Zebra's face, thus forming a dark blaze. FIG. 74.— Diagrammatic sketches of the faces of Horses ; (a) shows a full white ' blaze ' ; (d) a white star on the forehead ; (b and c) intermediate contractions of the ' blaze '; ( x ) indicates the white part on a dark ground. Then, as black is interchangeable with white, in some dark Horses we see a complete white blaze, occupying the whole of the lozenge- shaped face of the Horse, as shown in Fig. 74 (a). The other figures (b and c) are mere contractions of the blaze, until we come to a mere -vestige of the blaze in the shape of a small white star- between the eyes, which, in others, becomes completely obliterated. It would be tedious to go through all the variations that this blaze is subject to ; suffice it to say, that it sometimes invades the whole head, while in others it disappears completely. INTERESTING FEATURES IN HORSES, ETC. I have seen a Horse with a blackish star on a white blaze, and others, mostly bays, with a white star on a black blaze. This shows that although usually the star is white, it may, under certain circumstances, be exchanged for a black one ; and although usually the blaze is white, it sometimes can also be black. I have seen a perfect black blaze on the face of a light dun Horse. It was as full as the complete white blaze of (a) Fig. 74. These features in the domestic Horse are so persistent, even when all other spotting from the body has wholly disappeared, that FIG. 75. —(a) Faint radiating stripes on the forehead of a dark grey Horse ; (b] black radiat- ing stripes on the forehead of Burchell's Zebra — note its lozenge-shaped face. they would seem to have some deeper meaning than mere accidental marks. It is interesting to note that even the Zebra may have a small black star on its forehead between the eyes, as seen in Fig. 50. The persistence of these features may be because domestic Horses have been bred originally from parents that had them. Breeders of first-class Horses, I understand, would rather not have either stars or blazes, and it may be presumed that they have 1 70 STUDIES IN THE EVOLUTION OF ANIMALS endeavoured to select them out. Yet it is only exceptionally that they have succeeded in getting rid of them, for the large majority of Horses of all kinds one sees in the streets of London have these frontal marks, either fully developed or with vestiges of them ; so that I think we would be right in concluding that they come from a remote ancestry. 1 Our grandfathers have told us how their fathers expatiated on the merits of the Dutch Horses (old Lincolnshire blacks), of their size and feats of strength, how the blacks with white legs and blazes were most esteemed. These animals, or their descendants, in time became located all over England.' l This would appear a sufficient reason why blazed horses are so common in the streets of London. . They got it from the old Dutch Horses, * which with white legs and blazes were most esteemed? But this is not all, for Mr. F. Finn tells us 2 that ' The Onager was put to an Abyssinian wild Ass, and produced a hybrid ; it then bore, to a male Onager, a chestnut foal with a white blaze on the forehead ; but as this foal thus resembled neither parent, and in fact exhibited a Horse's rather than an Ass's marking, the case is surely one of analogous variation.' The names of the equines appear to me to be mere verbal distinctions used by systematists in classifying animals. In nature there seems to be no such distinction between Horse, Ass, Onager, Zebra, and Quagga, more especially as they all inter-breed. And this blaze on the forehead of the chestnut Onager's foal seems a reversion to some ancestral mark — white or black — whether we call the ancestor a Horse, an Ass, an Onager, or a Zebra. In this foal the blaze was white, but I have shown that the blaze may have originally been black, and caused by a fusion of the stripes on the * Pedigrees of British and American Horses,' by J. I. Lupton, Nineteenth Century, June 1894, p. 926. 2 'Some facts of Telegony.' — Natural Science, December 1893, p. 437- INTERESTING FEATURES IN HORSES, ETC. 171 Zebra's face. We have seen that white, black, and tan are inter- changeable. Dark Horses have either white or black blazes ; and dun and roan Horses have sometimes conspicuously black blazes. This interchange of colour — general or partial — occurs in various other animals. The black and tan Dog turns into tan and white ; the Dalmatian Dog is white, spotted black ; certain Deer are of a tan colour, spotted white ; and the stripped American Marmot is of a dark colour, with strings of white spots. Besides Horses there are many other animals that have black blazes on their face, such as several species of Antelope, several kinds of Deer, Ibex, Goats,1 etc., and the Bonte Bok Antelope (Damalis Pycarga} has a white blaze. Cattle have often a white star on the forehead, which we might consider, as in the Horse, a vestige of the white blaze. We may perhaps infer that the black blaze is a fusion of the Zebra's face-stripes, as we have before inferred that certain blotches and stripes on animals are fusions of isolated spots, but why a black blaze should turn into a white blaze, or tan feet should turn into white feet, as in the Dog, is more than I can tell. It would appear to be caused by a sort of atomic ' conjuring * of the nerve-centres hidden from our view even through the most powerful microscopes. Anyhow, we have ceased to think of super- natural causes for all these phenomena. There must be some natural causes for them, although at present we do not know them. All I know is that white, black, and tan colours in mammals are, as I said, interchangeable, and therefore I surmise that the Horse's white - blaze may have been originally black, and that in some varieties it changed into white, and has for some reason become more persistent in this colour. Whether the blaze of the Horse may have any relation to the 1 The male Bharal ( Ovis Nahura) has a fine black blaze. 172 STUDIES IN THE EVOLUTION OF ANIMALS insertion of the horns in some ancestral Rhinoceros is a question difficult to answer. We have seen that in certain animals skin armour has left certain marks when it disappeared, which are liable to change of colour, and not impossibly the blaze on the Horse's forehead may be vestigial of ancestral frontal and nose armour. It might lead to a certain amount of confusion to compare the Horse now with a Rhinoceros, and then with a ruminant, but Professor Alleyne Nicholson, in his Swiney Lectures of 1893, told us that if we go back far enough in time we shall find that animals which are now so distinct as ruminants and carnivora were in remote times mixed up in one animal, with features that had some- thing of both the branches into which that remote animal eventually bifurcated. According to Professor Weismann's doctrine, the object of sexual propagation is to mix up the separate descents of one individual with the separate descents of another individual, with the view of rendering the germ plasm more plastic and variable, so that it may the better provide the raw material of variations in organisms for the factory of adaptation by natural selection. We know that the characters of two distinct species, even of two distinct genera, were initially mixed up in one individual. Well, in bygone ages, it is very probable that animals which were largely differentiated in certain anatomical features were not so differentiated physiologically as to prevent their being mixed by sexual mating. If this be admitted, it would follow that what we now would call distinct species, might then have freely inter- married, and procreated what we now would call hybrids. For instance, a mixture of hornless, one-horned, and two-horned Rhinoceroses, if they happened to come together, might have inter- bred and become mixed. In- past ages this may have been a frequent occurrence. So with Antelopes, Horses, etc. INTERESTING FEATURES IN HORSES, ETC. 173 Some one might say that intermixture would eventually have produced an average structure, and all differences would be sup- pressed. But this does not appear likely in all cases, for we know that six-fingered people, although diluted with normal blood, have rather strengthened than suppressed the monstrosity. Such intermixtures are not at all imaginary, for we know that the Pheasant will procreate with the common fowl, and different species of Pheasants will interbreed. And among plants, species so distinct anatomically as a L