The Zoologist/4th series, vol 4 (1900)/Issue 709/Notes and Queries
NOTES AND QUERIES.
MAMMALIA.
In the British Gallery of the National Museum the Harvest Mouse (Mus minutus) is at present unrepresented, on account of the lack of specimens. I therefore venture to ask the kind assistance of readers of 'The Zoologist' in remedying this deficiency. I may add that specimens of all the British Bats, with the exception of the Noctule and the Long-eared species, are likewise wanted for the same gallery. Specimens should be forwarded to me at the Museum.—R. Lydekker (British Museum (Natural History) London, S.W.).
AVES.
Mistle-Thrush attacking Squirrel.—On April 27th last I was noticing the nest of a Mistle-Thrush (Turdus viscivorus) in an oak tree, when a Squirrel by chance passed along the branch on which the nest was; the female (I presume) left the nest and attacked the Squirrel violently, darting furiously at it and screeching loudly, until it had passed on to the next tree; she then squat upon a limb for a few moments, with wings partly extended and drooping, again taking possession of the nest a few minutes afterwards.—Stanley Lewis (Wells, Somerset).
Crossbills at Shrewsbury.—On June 24th and 25th a number of Crossbills (Loxia curvirostra) visited my garden. I counted seventeen in one place, and there were others in different parts. As most of them were young birds, I imagine they have been bred in the neighbourhood. They were wonderfully tame, feeding close to the windows on the seeds of the wych-elm, with which the lawn was covered. I may mention that a pair of these birds frequented my garden in January and February of this year. Probably they had a nest, but I could never find it.—R.H. Ramsbotham (Merle Brace, Shrewsbury).
Early Appearance of Swift.—The arrival of our summer migrants has in almost every instance been unusually late, and now (May 15th) the Swallow and the two species of Martin are not abundant; but this need not be wondered at when we consider the wintry weather that has prevailed. The Swifts (Cypselus apus) seem to have come in fair numbers, and, strange to say, I saw two on April 26th, which was a very early date, especially during this exceptional spring, for this usually late visitor. In ordinary seasons it is seldom seen with us before the end of April or beginning of May. I have a record as early as April 18th. But this season everything ornithological, entomological, and botanical appears uncertain, and out of its usual order.—G.B. Corbin (Ringwood, Hants).
The Great Spotted Woodpecker in Surrey.—Dendrocopus major has become so rare a bird in Surrey that the successful rearing of a brood deserves to be recorded. Early in June I happened to notice a hole in the trunk of a partially decayed birch tree in an unfrequented part of the Hurt Wood, near Shere. The hole was circular, about fifteen feet from the ground, and appeared to be the work of a Woodpecker. On tapping the trunk the cries of young birds greeted my ears, and I therefore returned the following morning with a glass to watch for the old birds, and ascertain their species. After waiting about twenty minutes a female Great Spotted Woodpecker suddenly flew against the trunk, but, catching sight of me, swerved aside and retired to a small oak tree a few yards from where I sat. Here she perched upon a horizontal branch, lengthways, after the fashion of a Nightjar. She remained almost motionless (thinking apparently that she was invisible), and I was able for a quarter of an hour to examine her with my glass. She had in her bill a large bunch of insects, which, finding inconvenient, she deposited on the branch in front, but removed when taking her departure. When the male bird flew to the hole, as happened in due course, she warned him of the danger with loud and alarming cries of "quick," often repeated at regular intervals. Both birds then retired to a distance, and kept up their answering alarm-notes. After about half an hour the male flew against the further side of the birch, and peered round the side of the trunk in my direction. The young ones had by now become vociferous; but, though I remained about an hour, neither parent ventured to enter the hole. I am told that the brood was fledged a few days later. The Lesser Woodpecker (D. minor) may still be seen in a good many places in Surrey, and, though very shy and difficult to discover, is not so very rare. Gecinus viridis is abundant, and, I think, increasing in the unbuilt-over portions of Surrey.—Harold Russell (Shere, Surrey).
Hoopoe in Hants and Dorset.—From information received from friends residing in widely separated localities, both east and west, and whose descriptions could be only referable to this handsome and conspicuous species (Upupa epops), I infer that it has visited us in some numbers, contrary to its usual scarcity; and on May 2nd I saw a specimen which had been found dead somewhere on the borders of Dorset, apparently starved. The body was very emaciated, and one wing had been injured, as if by a stone, which must have prevented flight, and possibly was the cause of its poor condition. I am glad to say I have not heard of a specimen having been wilfully killed, and I suppose it is too much to hope that the birds recorded were of Hampshire origin. A writer in the 'Field' of January last recorded the nesting of the species two consecutive years in South Hants, the exact localities being wisely withheld for obvious reasons.—G.B. Corbin (Ringwood, Hants).
Spoonbill at Great Yarmouth.—On June 7th a magnificent Spoonbill (Platalea leucorodia) was seen on Breydon, where I put it up. Black-headed Gulls, out of curiosity, were keeping it company, and they followed it to another resting place, not he them. I also saw two on the night of June 9th (not including the same bird), in company with Black-backed Gulls. Twelve were seen on June 4th for an hour or two on Breydon, and afterwards observed at Waxham.—Arthur Patterson (Ibis House, Great Yarmouth).
Hybrid Pheasant.—It is well known how readily the various species of Pheasants interbreed—sometimes even with the poultry of the farmyard—and this to such an extent that what is said to be the original stock, with dark uniform steel-blue neck and dark legs, is now seldom met with where extensive rearing is practised. Thus the size and consequent weight have in many instances deteriorated, and the plumage has become so varied that in some cases it is almost impossible to say to what particular species or "strain" in this most beautiful plumaged class of birds some individual specimens belong. I am alluding to birds in a semi-wild state, and not to those kept in confinement, for in the latter case, if I may judge from a series of skins I saw some time since, the variation in plumage is very great, especially with the Amherst and Golden Pheasant. I have heard it asserted—whether rightly or wrongly, I cannot say—that the Common Pheasant (meaning, I suppose, the hybridized bird so commonly reared) seldom interbreeds with the "Golden." In the spring of 1898 a gamekeeper informed me that in one of his covers he had seen a common cock Pheasant consorting with a hen "Golden," and subsequently he found her nest, with, I believe, seven eggs in it, five of which were duly hatched. During the shooting season of 1898–9 one of these birds was killed—a cock—of such a peculiar colour that the proprietor of the shooting had it preserved and mounted. It was of a uniform reddish cinnamon, except the neck, which was of a bronze-copper shot with shades of purple. The development of its plumage was, however, normal, except the tail, which was longer than in the ordinary bird. Last season two others of the brood were killed, and, being a year older, one of them at least was more fully developed; but, although a second season's bird, it had no indication of spurs. Its tail was of the same form, but much longer than in the ordinary cock; the two upper feathers of a pale buff, with slight indications of darker transverse markings; under feathers barred after the manner of Golden. Body: under parts uniform bright reddish brown; back more yellow, dappled thickly with ash-brown and black; neck a purple-bronze, with small portion of scarlet on cheeks. It had no crest, but the "cape" or "tippet" was represented by a number of feathers two and a half or three inches long, of a uniform rich brown colour, which hung in a pendent manner from the back of the head, thus giving the bird a very peculiar appearance.—G.B. Corbin (Ringwood, Hants).
Albatross near Faroe.—It may interest readers of 'The Zoologist,' to hear of the occurrence of another specimen of the Albatross (Diomedea melanophrys) in or near Faroe. Miss Elizabeth R. Taylor, who is residing in Faroe for the purpose of studying these isles and their natural and other history, writes me as follows:—"It has occurred to me that you may be interested in knowing that another Albatross has been shot near the Faroes this year (the last one being the Albatross of Mygganoes, shot in 1894). This one was shot at sea, on the Faroe Banks, about seventy or eighty miles south-west of Thorshavn. I heard of it just before I left Thorshavn, and did not ascertain any particulars, whether male or female. It is of the same species as the Mygganoes one. The taxidermist at Naalsoe is preparing the specimen now, and I suppose it will be sent to the Museum at Copenhagen." With reference to the above interesting communication, I need not refer to the previous records of the Albatross in the Faroe Seas, as these records are so recent. However, I may mention that Mr. Thomas Parkin, with whom I have been in correspondence on the subject, intends to bring out a monograph of the genus, and has already delivered a lecture upon the different species. This lecture was given before the Hastings and St. Leonards Natural History Society at the Museum in the Brassey Institute on April 10th last, and printed in the 'Hastings and St. Leonards Observer' of the 14th of that month.—J.A. Harvie-Brown (Dunipace House, Larbert, N.B.).
Migration Notes from Great Yarmouth.—The spring migration of 1900, more particularly of the Grallatores, has been, in this neighbourhood, a very disappointing one, the prevailing winds being north-east, or thereabouts, and the weather exceptionally bleak and cold. South-easterly winds are those most favourable to the visitation of the water-loving species, although any wind from the southward suits the land-birds equally well. The other side of the North Sea has no doubt seen the bulk of passing migrants, and many birds must have put off their journey until the last extremity, and then have gone on straight ahead without gossiping, as they do in favourable seasons on Breydon, resting and feeding, thus breaking the trip. The following extracts from my note-book will give a pretty fair idea of these movements this season:—Wigeon fairly plentiful, Feb. 17th. Small bunches of Larks flying north-east, Feb. 20th. Fifty Curlews on Breydon, Feb. 27th. Flocks of Ringed Plovers on Breydon, March 1st. Sailed past several Dunlins, on March 28th, on edge of "flat"; they were as grey as in depth of winter. About two thousand Starlings on a marsh, March 28th. Late for so big an assembly. Query, were they late-hatched birds? Will they remain unnesting? Numbers of Little Auks washing ashore dead; thirty picked up last week in March; also some Puffins. Wedge-flights of Starlings moving seawards, March 29th. About one hundred Wigeon on Breydon, April 17th. Six Geese passing over (Whitefronts?), April 18th. A few Godwits reported on beach, April 17th. Sailed into flock of one hundred Wigeon, April 20th. Several Kentish and Common Crows together on Breydon mud-flats, April 20th. Five Kentish Crows on Breydon late as May 11th; one had a drooping wing; the other laggards were no doubt anxiously wishing to be off, but loath to leave him; they were gone next day. One Spoonbill said to have been seen a few hours on Breydon on April 28th; on June 7th twelve were reported to me as seen there; I was on Breydon myself, but it was so rough I went in a leeward direction, otherwise I should have gone by the very flat they were said to have rested upon for only an hour or two. I did not see them. By one or two they were mistaken for Swans, a not unusual error to those who see them at a distance. Several Grey Plovers on Breydon, May 5th; wind south-west, suddenly veering to south-east by next morning—a shift I expected. A precisely similar thing happened on May 25th, the wind backing from north-east to south-east in a few hours (cf. ante, p. 162). Some delightfully "Black-breasted" Plovers (old gunner's nickname for Greys) on Breydon, May 10th; they were very tired, and I "quanted" to within a few paces and watched them. Only Knots seen, May 9th; about five or six. Seven Swifts arrived on May 11th; an early arrival. We usually expect five pairs. They vanished for a few days, it being cruelly cold, and returned again. Only very few Godwits. Saw three on May 12th; have seen only one or two others since. Saw a pair of Shovelers on May 16th; they undoubtedly nested in the vicinity, but, as they have frequently visited Breydon since, their nest may have been rifled. Saw them to-day (June 10th). Observed Whimbrel in couples, May 16th; they were numerous a week before, hunting singly or in small scattered flocks. Several there as late as to-day (June 10th). A few Yellow Wagtails on marshes, May 16th, by no means plentiful as of yore. Saw one Turnstone, May 28th; only one I have seen. A goodly sized flock of Ringed Plovers on May 27th; a few on Breydon to-day (June 10th), possibly birds nesting on the adjacent coast; also three Dunlins, probably non-nesters. Have seen no Terns, neither Black, Arctic, or Common. Hirundines rather numerous in adjacent villages. Cuckoos numerous; locally nesting Redshanks show no falling off this season; Common Sandpipers were fairly numerous last month. There may be nothing recorded above of any importance, but the bare summary of my observations will show how scanty has been the local record, and may serve for comparison with other districts.—Arthur Patterson (Ibis House, Great Yarmouth).
ARACHNIDA.
Rare English Ticks.—The study of Ticks (Ixodidæ) has been much neglected in England. Mr. E.G. Wheler, of Alnwick, has, however, recently taken up the subject, and has published, in 'Science Gossip,' a series of short papers upon some of our British species. In the hope of inducing others to take an interest in these parasites, I venture to put on record the occurrence in England of two species which have not, so far as I can ascertain, been previously recorded from this country, and of a third which is certainly not common. It is true that Mons. G. Neumann, in his recent monograph of this group, states that he has seen specimens of the first two, belonging to the Bureau of Animal Industry of Washington, that were taken off English Sheep; but whether the Ticks were collected off Sheep in England, or after their importation to America (which is a very different matter), I am unable to say. I may add that Mr. Wheler took up the study of these parasites on account of their connection with the malady known as "louping ill," which is so destructive to Sheep in some parts of England. It is known, too, that great havoc is wrought amongst cattle in the United States and our own colonies by these pestilent Arachnids; and, since there are some reasons for supposing that there may also be a causal connection between the bites of these parasites and that deadly tropical disease, "black-water fever," it is safe to predict that within the next few years there will be a boom in Ticks rivalling that in Mosquitoes at the present time. I should be grateful for any specimens readers of 'The Zoologist' may come across. They should be preserved in alcohol.
1. Dermacentor reticulatus, Fabr.—Specimens of this Tick were sent to the British Museum for determination by Mr. Richardson, of Stoke House, Revelstoke, Devon. Mr. Richardson writes:—"These Ticks are a pest of this immediate neighbourhood. They do not bite human beings, but punish Sheep and Dogs like the ordinary Tick. A farmer tells me they were not known here fifteen years ago, and that they appear about January, and disappear about May, being very plentiful in March and April. It is strange that they should not be known a few miles away."
2. Hæmaphysalis punctata, Can. and Fanz.—Specimens of this species were taken by Mr. F. Pickard-Cambridge at Dungeness. They were found amongst the shingle on the beach, and also upon a Hedgehog.
3. Hyalomma affine, Neum.—A specimen (a gravid female) of this species was sent for determination to the British Museum in May, 1898, by Mr. P.C. Essex, who picked it up at Feltham. The specimen is very much larger than the ordinary British Tick, and closely resembles the so-called "Camel-Tick" of Egypt and India. My suspicion that it actually was an example of this species that had interested Mr. Essex was partially confirmed at the time by my inquiry eliciting the information that a travelling menagerie had passed through Feltham a short while before. Subsequent examination of the specimen, however, has shown that it is referable to H. affine, Neumann, a species which its describer mentions as common on Tortoises (Testudo græca and mauritanica), and records as taken in England off one of these reptiles. Hence there is no reason to doubt that the Feltham specimen was introduced, and is not a descendant of British-born parents.—R.I. Pocock (Nat. Hist. Museum, South Kensington).
ORGANIC EVOLUTION.
In the last copy of 'The Zoologist' which has come to hand in this out-of-the-way part of the world (Mashonaland), I find that Mr. Distant has terminated his series of deeply interesting articles on "Biological Suggestions," relating to "Assimilative Colouration and Mimicry." In these articles he has brought together a most valuable collection of observations and remarks, made by all sorts and conditions of men, upon the fascinating problems of animal colouration, a collection which bears eloquent testimony to the wide and careful reading of the author; indeed, although it may appear ungrateful to say so, the material offered for the contemplation of the reader is almost bewilderingly profuse—so much so, in my opinion, as frequently to obscure the real aim and object of the essays under a mass of citations. Thus, although many of the points raised by Mr. Distant appeared to be open to discussion, it seemed advisable to see the articles as a whole before attempting to comment on the conclusions which he suggests should be drawn from the records therein brought forward. I deal only with his remarks on "Assimilative Colouration," published in Sept. and Nov. 1898 (Zool. ser. iv. vol. ii. pp. 377 and 453).
If I have rightly comprehended Mr. Distant's meaning, his general object is to show that the theory of natural selection has been pushed too far by some of its supporters in their endeavour to explain colouring in nature, and to this end he propounds two suggestions: primarily, that "in the long past animals were uniformly and assimilatively coloured in connection with their principal surroundings" (l.c., p. 461); and, secondarily, that "it is at least probable that, where we have protective resemblance in a unicolourous condition, it is a survival of original assimilative colouration, and not a direct product of natural selection" (p. 473). The question to be considered is, whether these propositions have been sufficiently maintained.
I may here state that, so far as concerns the endeavours of some biologists to make natural selection responsible for every trifling detail of colour, I can sympathise to some extent with Mr. Distant's general attitude; as, for instance, when it is attempted to explain trivial local variations by the purely hypothetical and quite unprovable assumption that these are correlated with certain obscure but useful constitutional characters, of which we know nothing at all, on the ground that it is these characters, and not the trivial colours themselves, that have been operated upon by natural selection. Such contentions certainly do not commend themselve in the present state of our knowledge. But when one contemplates the vast mass of valuable biological work, both in arduous experiments and paisntaking observations, that has been and is still being accomplished by the champions of natural selection in order to test the validity of the Darwinian theory in every hole and corner of the organic world, one can only read with unfeigned astonishment the assertion that "the tendency to explain all problems by natural selection is to-day greatly retarding the study of bionomics. It is not one whit removed from the proferred explanation of the old teleologists, and represents as little thinking"! An endeavour to refute this assertion would be out of place here; and I need only mention, with special reference to the last phrase of the above quotation, that although the explanation on the selection theory of the inter-resemblance of distasteful insects appears simple enough at the present day, yet for twenty years it baffled the ingenuity of such men as Bates and Wallace, until Fritz Müller put forward the ingenious theory of mimicry now associated with his name.[1]
But to return to Mr. Distant's suggestions. We are at once confronted with a difficulty in that no definition is offered of the exact significance of the term "assimilative colouration," which is evidently loosely applied, seeing, for example, that the brilliant red on the wings of the African Touracos is given as an instance of partial assimilative colouration (p. 460),[2] apparently on the assumption that these birds eat copper[3]—the common copper ores of the country being green. We must, therefore, assume that assimilative colouration, as here understood, signifies a close similarity of colouring between an organism and its environment, due to the direct action of the latter upon the organism, either through nerve stimuli or through the direct absorption of the environment into its system, such colouring being essentially non-significant, any utility it may possess being entirely fortuitous.
The general proposition that in the earliest ages of the earth's history such assimilative colouration everywhere prevailed is a perfectly legitimate surmise, though a mere surmise it must ever remain. But, on the other hand, while even the most advanced selectionists will doubtless allow that the earliest organic colour, or colours, were probably non-significant, they would be quite justified in opposing the hypothesis of assimilation, as above defined, on the ground that there is no reason whatever to suppose that the direct action of any environment upon an organism must necessarily produce in it a colouration identical with that of its environment; and Mr. Distant's own examples might be cited in support of this contention, e.g., that a diet of hemp-seed turns Bullfinches black; that red and yellow feathers are produced in certain Green Parrots by feeding them on fish; that the feathers of Cotinga can be transformed from purple to brilliant red by the application of heat, and so forth—in all of which instances there is no colour similarity between the various causes and their effects;[4] and still further experimental evidence might be adduced. Indeed, when we consider the numerous instances of non-significant colours known to us both in the organic and inorganic worlds, there can be no reasonable objection to the hypothesis that the earliest organisms might have developed, through purely physico-chemical causes, non-significant colours, both brilliant and otherwise, which might, or might not, have corresponded with those of their respective environments; and thus, when natural selection did become a vera causa, there would already have been a considerable range of colour upon which it might operate. However, with regard to the first appearance of this factor, it seems more reasonable to suppose that this was practically synchronous with the first appearance of organic life, though the struggle for existence at that period would be solely against the physical forces of nature, and thus natural selection would then have little or no effect upon colouration, except perhaps indirectly.
Supposing, however, that, for the sake of argument, we agree to accept Mr. Distant's general suggestion, we have yet to consider the correctness of his corollary thereto, which is really the essential portion of his paper. According to this view: "If the earliest forms of life are to be sought only in an ancient geological record, it is also in that phase of animal existence that the beginnings of colouration must have developed. It therefore seems possible that assimilative colouration may have been a first and a very general consequent in animal development; and that the subsequent protective resemblance acquired by numerous living creatures through the process of natural selection, when life had advanced to the competitive stage, is far too frequently used as an explanation for whole series of uniform phenomena in colouration, which have probably survived unaltered from remote antiquity." (Pp. 383, 384.) And again: "As adaptation implies a previous state of variation, which again predicates a more or less stable condition from which variation arose, we come to the conclusion that the pre-variable condition was a unicolorous one, and from the data—scanty indeed—at our disposal, are inclined to suggest that the unicolorous hue was originally due to assimilative colouration." (P. 471.) In other words, it is suggested that the present unicolorous hues of such organisms as green birds and caterpillars, isabelline desert animals and flat fishes, &c, are preferably to be explained on the ground that they are survivals of an assimilative colouring which was acquired in early geological times, its persistence being due not to the direct action of natural selection, but to the fact that this colouring happened, quite by chance, to be of vital importance to the animals.[5]
Now, apart from other objections, the acceptance of such an hypothesis appears to me to land us at once upon the horns of a dilemma. Either we have to believe that these unicolorous animals have existed as we now see them since the "early stages of animal life," or we have to assume that these organisms, with their numerous ancestry, right back to the low generalised form from which they sprung in "remote antiquity," must have existed through countless ages of time and innumerable geological and climatic changes in an unchanging environment to which their primæval assimilative colouring chanced to be so well adapted, that natural selection has been quite unable to affect them in that respect throughout the entire period; although, be it noted, their structure has undoubtedly undergone, in most cases, very considerable modification.
This conclusion is to me almost as untenable as the previous one; and, as it is difficult to perceive in what other way the present phenomena of colour can be explained upon the suggestion of the survival of ancestral assimilative colouring, it seems to me that this hypothesis must fall to the ground. The fundamental error of the suggestion appears to lie in the fact that the development of colour has been regarded in a purely abstract light, and not in connection with the development of any particular animal or group of animals, as must be done in order to arrive at any reliable results.
It must be particularly pointed out that in Mr. Distant's general discussion of the subject he has most clearly suggested that the present day colouring, which is classed by him as assimilative (in opposition to adaptive) was only developed in the earliest geological epochs, and prior to the first appearance of natural selection as an efficient factor—according to his conception of that first appearance. Fortunately we are able to obtain, from certain passages, some idea as to this conception, for with regard to the Lias formation of the Jurassic Period (Mesozoic), when the gigantic Enaliosaurians abounded, it is freely admitted that "Here we see natural selection, with its iron and implacable rule, a real factor";[6] and, further, in the later essays on "Mimicry," good cause is shown for the recognition of the occurrence of natural selection so far back as the Carboniferous Period in Palæozoic times.
But when we come to consider the examples adduced in support of the above suggestion, we at once find that the fundamental proposition is practically disregarded. A single instance will suffice. Referring to the colouring of primitive man, it is remarked that: "Their colour would have been uniform, either derived from their more brutish ancestors, or, possibly, a more assimilative colouration may have ensued to the soil on which they walked."[7] It will be thus seen that the vast majority of instances cited by Mr. Distant are quite inappropriate as illustrations of his fundamental suggestions, though possibly they might be brought forward in support of a theory that assimilative colouration has been sporadically developed from recent geological times down to the present day.
On glancing through the quotations given, one is at once struck by the practically complete absence of anything in the way of experimental evidence as to the direct action of the environment, and this is the more strange seeing that such evidence is actually available. It will be sufficient to refer to the splendid series of exhaustive experiments made by Prof. Poulton upon the influence of both food and surrounding colours on the larvæ and pupæ of various Lepidoptera. These experiments have been carried out with the most scrupulous care and exactitude, and the conclusions which can be drawn from them are worth scores of hasty observations and occasionally inaccurate generalizations made by travellers and sportsmen. It would be beside the point to enter into details as to the results obtained by Prof. Poulton, since we are only discussing the possibility of the survival of primæval assimilation; but it may be mentioned that these experiments definitely prove that certain of these organisms possess, in varying degrees, the capacity of being modified in colour by the direct action of different light-waves; and, further, I consider it is sufficiently demonstrated that this capacity can only be satisfactorily explained by the theory of natural selection, and not by any theory of purely internal or external causes.
But to resume: with reference to the attempt to explain the crimson colour in the wings of the African Touracos (Turacus and Gallirex) as being due to the occurrence of copper in the districts which they frequent, I quite agree with the objections raised by Dr. Bowdler Sharpe.[8] In my experience of these beautiful birds, both in Natal and Mashonaland, I can find no connection between their distribution and the occurrence of coppers; and besides, the fact, noted by Mr. Distant, that they have been known to moult several times in captivity in England without impairing the brilliancy of their feathers, appears to entirely negative any such direct connection. Moreover, no attempt is made to explain why it is only these birds which are affected in this curious way; or why, in them, the effects are confined to a limited number of feathers.
It is noticeable that wherever phenomena are explained upon the theory of natural selection a detailed explanation of the "why and wherefore" is always expected, whereas exponents of theories of purely environmental causes are so frequently content to confine themselves to the widest of generalities.
Among the instances quoted by Mr. Distant as bearing on the suggestion that "Even the obscure problem of the colouration of mankind may have originally—and before migration became such an important factor in modification—been due to a more or less assimilative colouration," are some remarks (p. 398) on the natives of Mashonaland from a paper by the late Mr. W. Eckersley, whose acquaintance I made when he visited this country seven years ago. In one portion of his paper Mr. Eckersley states that "large areas of red soil are frequently met with"; in quite another part he mentions that the colour of the Mashonas is "dark chocolate-brown, some shades removed from black." As a matter of fact, the absolute proportion of red soil in Mashonaland is comparatively small, and, moreover, the vast majority of the Kafirs live on the huge outcrops of granite which constitute the great bulk of the plateau. But, quite apart from this, any argument for the hypothesis of assimilative colouration, based on the relation of the Mashonas, or indeed any of the Bantu tribes, to the soil they now inhabit, is entirely vitiated by the fact that we know that these tribes have come down from the North comparatively recently, and some of their migrations, at least, have taken place within historic times.[9] I certainly cannot agree with Mr. Distant's somewhat sweeping assertion that "the colour of mankind can in no sense come under the explanations of protective or aggressive resemblance..... or nuptial colouration." Any one who has seen a Kafir in his native bush must have been struck by his incouspicuousness as compared with a white man, and there can be little doubt that this assimilation to his surroundings must be of considerable value for aggressive purposes (as, for instance, in stalking game which might frequently be of vital importance); further, Darwin himself has argued ('Descent of Man,' ed. 2, p. 604) that racial colouring may be to some extent due to sexual selection.
Unfortunately, suggestions of the type referred to above are only too easily made, and might readily be multiplied with a little ingenuity. For instance, we might suggest that, as swallows are eminently aërial birds, the great predominance of blue in their colouring is due to continual exposure to the blue sky, and we might seek for confirmation of this in the fact that the blue colour is principally found on the upper surface, which is most exposed to this influence; and, finally, we should pass over in silence the little difficulty as to the colouring of the Swifts.
Finally, I must mention the notes on the colouration of the Cat tribe. After referring to Darwin's remarks on the stripes occurring on young Lions, and also to Steedman's observation that these markings are likewise fœtal (p. 462), Mr. Distant proceeds to say: "It seems more in consonance with present knowledge and opinion to consider that spots, though primitive, were not original, and succeeded, not preceded, unicolorous ornamentation, which has survived only where it has been more or less in unison with the creature's environment, and so afforded aggressive protection, as in the case of the Lion" (p. 464). Seeing that the fœtal markings distinctly prove that, at least, the immediate ancestors of the Lion were striped animals, and that therefore its present unicolorous coat must have been subsequently acquired, it is certainly difficult to understand how this animal can be adduced as a survival of a supposed primitive assimilative colouration![10]
In conclusion, I can only regret that my notes on Mr. Distant's paper have been perforce entirely critical. Although I, as a selectionist, cannot regard as sound the suggestions which he puts forward, I can still appreciate their value in drawing attention to these interesting topics. And I trust that some reader of the 'Zoologist,' more competent to discuss these matters than myself, will in turn point out any errors that may exist in my own arguments and contentions; for it is only by healthy discussion, followed by more careful observation and experiment, that we can hope to attain a true insight into those large biological problems, the solution of which is the ultimate aim of all natural science.—Guy A.K. Marshall (Salisbury, Mashonaland).
- ↑ Of course Mr. Marshall does not suggest that Müller's theory has found universal acceptance?—Ed.
- ↑ The exact passage to which exception is taken reads as follows: "This cannot be taken as an instance of pure, but only partial, assimilative colouration, but is sufficient to prove that colour may be largely derived from the mineral constituents of the earth's surface, and in this way can scarcely be altogether ascribed to the action of 'natural selection.'"—Ed.
- ↑ The "assumption that these birds eat copper" is not found on the page criticised; and is negatived by a quotation given from Mr. Monteiro (p. 459).—Ed.
- ↑ These examples were prefaced in the article criticized by the remark: "The view of a direct action caused by a constant food on animal colouration has frequently been remarked."—Ed.
- ↑ The inference, "quite by chance to be of vital importance to the animals," is not to be found in the pages criticized.—Ed.
- ↑ This quotation with its context is as follows:—"Thus, after a period of animal evolution which may be computed by millions of years, and in which fish abounded, perhaps not yet altogether under a severe stress of selection and survival, the Mesozoic period arrives, when, in the words of Oscar Schmidt, 'the Placoids and Ganoids, hitherto predominating in the ocean almost without a foe, now found overwhelming enemies in the true Sea-lizards or Enaliosaurians, especially the Ichthyosaura and Plesiosauria.' Here we see natural selection, with its iron and implacable rule, a real factor in the lives and development of these creatures, connected and increasing with an advancing animal evolution, but still only a term to express the modifying influences incidental to a struggle for existence" (pp. 388–9).—Ed.
- ↑ Quotations are best unabridged. The following is as printed:—"As De Quatrefages has remarked, 'The first men who peopled the centre of human appearance must at first have differed from each other only in individual features.' Their colour would have been uniform, either derived from their more brutish ancestors, or possibly, as their habits became less arboreal, a more assimilative colouration may have ensued to the soil on which they walked" (p. 403).—Ed.
A previous paragraph, not quoted, reads: "But although facts may be found to support new suggestions, such as a possible original assimilative colouration of man, the quest for such produces other recorded observations, which, though not altogether contradictory to the view, still point to other causes, support other conclusions, and reassert the problem we seek to solve" (p. 400).— Ed. - ↑ Dr. Sharpe's objections are given on the page criticized, and given as a qualitative contradiction.—Ed.
- ↑ Mr. Marshall does not seem to have read a passage which might have mollified his strictures:—"It is true that assimilative colouration seems to have little modified the colour of indigenous races, even in Africa, if we take a comprehensive view of the whole area. But we must not forget that men have so often migrated from their original birthplaces, and, more than that, much mixture has taken place" (p. 399).— Ed.
- ↑ On page 462, the writer of these suggestions, which Mr. Marshall is criticizing, actually states: "A fact, however, which very strongly stands against the view of original assimilative colouration here assumed, is found in the markings of the young of all the unicolorous Cats—Lion, Puma, &c.—which are more or less indistinctly spotted or striped; and as many allied species, both young and old, are similarly marked, Darwin has observed that 'no believer in evolution will doubt that the progenitor of the Lion and Puma was a striped animal, and that the young have retained vestiges of the stripes, like the kittens of black Cats, which are not in the least striped when grown up.' .... Taking the cases of the Lion, Puma, and Cheetah, we see that the two first, unicolorous in their adult stage, apparently show by their spotted young a derivation from a similarly coloured ancestor, whilst the spotted Cheetah, from the apparent evidence of its unicolorous young, would point to a totally different conclusion" (p. 463).—Ed.