Englishman of the western half of England and the Irishman of the
eastern half of Ireland? For what reason does the one deserve the
name of a "Celt," and not the other? And further, if we turn to
the inhabitants of the western half of Ireland, why should the term
"Celts" be applied to them more than to the inhabitants of Cornwall?
And if the name is applicable to the one as justly as to the other,
why should not intelligence, perseverance, thrift, industry, sobriety,
respect for law, be admitted to be Celtic virtues? And why should we
not seek for the cause of their absence in something else than the
idle pretext of "Celtic blood?"
I have been unable to meet with any answers to these questions.
V. _The Celtic and the Teutonic dialects are members of the same
great Aryan family of languages; but there is evidence to show that a
non-Aryan language was at one time spoken over a large extent of the
area occupied by Melanochroi in Europe_.
The non-Aryan language here referred to is the Euskarian, now spoken
only by the Basques, but which seems in earlier times to have been
the language of the Aquitanians and Spaniards, and may possibly have
extended much further to the East. Whether it has any connection with
the Ligurian and Oscan dialects are questions upon which, of course,
I do not presume to offer any opinion. But it is important to remark
that it is a language the area of which has gradually diminished
without any corresponding extirpation of the people who primitively
spoke it; so that the people of Spain and of Aquitaine at the present
day must be largely "Euskarian" by descent in just the same sense as
the Cornish men are "Celtic" by descent.
Such seem to me to be the main facts respecting the ethnology of the
British islands and of Western Europe, which may be said to be fairly
established. The hypothesis by which I think (with De Belloguet and
Thurnam) the facts may best be explained is this: In very remote times
Western Europe and the British islands were inhabited by the dark
stock, or the Melanochroi, alone, and these Melanochroi spoke dialects
allied to the Euskarian. The Xanthochroi, spreading over the great
Eurasiatic plains westward, and speaking Aryan dialects, gradually
invaded the territories of the Melanochroi. The Xanthochroi, who
thus came into contact with the Western Melanochroi, spoke a Celtic
language; and that Celtic language, whether Cymric or Gaelic, spread
over the Melanochroi far beyond the limits of intermixture of blood,
supplanting Euskarian, just as English and French, have supplanted
Celtic. Even as early as Caesar's time, I suppose that the Euskarian
was everywhere, except in Spain and in Aquitaine, replaced by Celtic,
and thus the Celtic speakers were no longer of one ethnological stock,
but of two. Both in Western Europe and in England a third wave of
language--in the one case Latin, in the other Teutonic--has spread
over the same area. In Western Europe, it has left a fragment of the
primary Euskarian in one corner of the country, and a fragment of the
secondary Celtic in another. In the British islands, only outlying
pools of the secondary linguistic wave remain in Wales, the Highlands,
Ireland, and the Isle of Man. If this hypothesis is a sound one, it
follows that the name of Celtic is not properly applicable to the
Melanochroic or dark stock of Europe. They are merely, so to speak,
secondary Celts. The primary and aboriginal Celtic-speaking people are
Xanthochroi--the typical Gauls of the ancient writers, and the close
allies by blood, customs, and language, of the Germans.
IX.
PALAEONTOLOGY AND THE DOCTRINE OF EVOLUTION.
(THE ANNIVERSARY ADDRESS TO THE GEOLOGICAL SOCIETY, FOR 1870.)
It is now eight years since, in the absence of the late Mr. Leonard
Homer, who then presided over us, it fell to my lot, as one of the
Secretaries of this Society, to draw up the customary Annual Address.
I availed myself of the opportunity to endeavour to "take stock"
of that portion of the science of biology which is commonly called
"palaeontology," as it then existed; and, discussing one after another
the doctrines held by palaeontologists, I put before you the results
of my attempts to sift the well-established from the hypothetical or
the doubtful. Permit me briefly to recall to your minds what those
results were:--
1. The living population of all parts of the earth's surface which
have yet been examined has undergone a succession of changes which,
upon the whole, have been of a slow and gradual character.
2. When the fossil remains which are the evidences of these successive
changes, as they have occurred in any two more or less distant parts
of the surface of the earth, are compared, they exhibit a certain
broad and general parallelism. In other words, certain forms of life
in one locality occur in the same general order of succession as, or
are _homotaxial_ with, similar forms in the other locality.
3. Homotaxis is not to be held identical with synchronism without
independent evidence. It is possible that similar, or even identical,
faunae and florae in two different localities may be of extremely
different ages, if the term "age" is used in its proper chronological
sense. I stated that "geographical provinces, or zones, may have been
as distinctly marked in the Palaeozoic epoch as at present; and those
seemingly sudden appearances of new genera and species, which we
ascribe to new creation, may be simple results of migration."
4. The opinion that the oldest known fossils are the earliest forms of
life has no solid foundation.
5. If we confine ourselves to positively ascertained facts, the total
amount of change in the forms of animal and vegetable life, since the
existence of such forms is recorded, is small. When compared with the
lapse of time since the first appearance of these forms, the amount
of change is wonderfully small. Moreover, in each great group of the
animal and vegetable kingdoms, there are certain forms which I termed
PERSISTENT TYPES, which have remained, with but very little apparent
change, from their first appearance to the present time.
6. In answer to the question "What, then, does an impartial survey of
the positively ascertained truths of palaeontology testify in relation
to the common doctrines of progressive modification, which suppose
that modification to have taken place by a necessary progress from
more to less embryonic forms, from more to less generalized types,
within, the limits of the period represented by the fossiliferous
rocks?" I reply, "It negatives these doctrines; for it either shows us
no evidence of such modification, or demonstrates such modification as
has occurred to have been very slight; and, as to the nature of
that modification, it yields no evidence whatsoever that the earlier
members of any long-continued group were more generalized in structure
than the later ones."
I think that I cannot employ my last opportunity of addressing you,
officially, more properly--I may say more dutifully--than in
revising these old judgments with such help as further knowledge and
reflection, and an extreme desire to get at the truth, may afford me.
1. With respect to the first proposition, I may remark that
whatever may be the case among the physical geologists, catastrophic
palaeontologists are practically extinct. It is now no part of
recognized geological doctrine that the species of one formation all
died out and were replaced by a brand-new set in the next formation.
On the contrary, it is generally, if not universally, agreed that
the succession of life has been, the result of a slow and gradual
replacement of species by species; and that all appearances of
abruptness of change are due to breaks in the series of deposits, or
other changes in physical conditions. The continuity of living forms
has been unbroken from the earliest times to the present day.
2, 3. The use of the word "homotaxis" instead of "synchronism" has
not, so far as I know, found much favour in the eyes of geologists.
I hope, therefore, that it is a love for scientific caution, and not
mere personal affection for a bantling of my own, which leads me still
to think that the change of phrase is of importance, and that the
sooner it is made, the sooner shall we get rid of a number of pitfalls
which beset the reasoner upon the facts and theories of geology.
One of the latest pieces of foreign intelligence which has reached
us is the information that the Austrian geologists have, at last,
succumbed to the weighty evidence which M. Barrande has accumulated,
and have admitted the doctrine of colonies. But the admission of the
doctrine of colonies implies the further admission that even identity
of organic remains is no proof of the synchronism of the deposits
which contain them.
4. The discussions touching the _Eozoon_, which commenced in 1864,
have abundantly justified the fourth proposition. In 1862, the oldest
record of life was in the Cambrian rocks; but if the _Eozoon_ be,
as Principal Dawson and Dr. Carpenter have shown so much reason for
believing, the remains of a living being, the discovery of its true
nature carried life back to a period which, as Sir William Logan has
observed, is as remote from that during which the Cambrian rocks were
deposited, as the Cambrian epoch itself is from the tertiaries. In
other words, the ascertained duration of life upon the globe was
nearly doubled at a stroke.
5. The significance of persistent types, and of the small amount of
change which has taken place even in those forms which can be shown to
have been modified, becomes greater and greater in my eyes, the longer
I occupy myself with the biology of the past.
Consider how long a time has elapsed since the Miocene epoch. Yet, at
that time, there is reason to believe that every important group in
every order of the _Mammalia_ was represented. Even the comparatively
scanty Eocene fauna yields examples of the orders _Cheiroptera,
Insectivora, Rodentia_, and _Perissodactyla_; of _Artiodactyla_
under both the Ruminant and the Porcine modifications; of _Carnivora,
Cetacea_, and _Marsupialia_.
Or, if we go back to the older half of the Mesozoic epoch, how truly
surprising it is to find every order of the _Reptilia_, except
the _Ophidia_, represented; while some groups, such as the
_Ornithoscelida_ and the _Pterosauria_, more specialized than any
which now exist, abounded.
There is one division of the _Amphibia_ which offers especially
important evidence upon this point, inasmuch as it bridges over the
gap between the Mesozoic and the Palaeozoic formations (often supposed
to be of such prodigious magnitude), extending, as it does, from the
bottom of the Carboniferous series to the top of the Trias, if not
into the Lias. I refer to the Labyrinthodonts. As the address of 1862
was passing through the press, I was able to mention, in a note, the
discovery of a large Labyrinthodont, with well-ossified vertebrae, in
the Edinburgh coal-field. Since that time eight or ten distinct genera
of Labyrinthodonts have been discovered in the Carboniferous rocks
of England, Scotland, and Ireland, not to mention the American forms
described by Principal Dawson and Professor Cope. So that, at the
present time, the Labyrinthodont Fauna of the Carboniferous rocks is
more extensive and diversified than that of the Trias, while its chief
types, so far as osteology enables us to judge, are quite as highly
organized. Thus it is certain that a comparatively highly organized
vertebrate type, such as that of the Labyrinthodonts, is capable
of persisting, with no considerable change, through the period
represented by the vast deposits which constitute the Carboniferous,
the Permian, and the Triassic formations.
The very remarkable results which have been brought to light by the
sounding and dredging operations, which have been carried on with
such remarkable success by the expeditions sent out by our own, the
American, and the Swedish Governments, under the supervision of
able naturalists, have a bearing in the same direction. These
investigations have demonstrated the existence, at great depths in the
ocean, of living animals in some cases identical with, in others very
similar to, those which are found fossilized in the white chalk. The
_Globigerinae_, Cyatholiths, Coccospheres, Discoliths in the one are
absolutely identical with those in the other; there are identical, or
closely analogous, species of Sponges, Echinoderms, and Brachiopods.
Off the coast of Portugal, there now lives a species of _Beryx_,
which, doubtless, leaves its bones and scales here and there in the
Atlantic ooze, as its predecessor left its spoils in the mud of the
sea of the Cretaceous epoch.
Many years ago[1] I ventured to speak of the Atlantic mud as "modern
chalk," and I know of no fact inconsistent with the view which
Professor Wyville Thomson has advocated, that the modern chalk is not
only the lineal descendant of the ancient chalk, but that it remains,
so to speak, in the possession of the ancestral estate; and that from
the Cretaceous period (if not much earlier) to the present day, the
deep sea has covered a large part of what is now the area of the
Atlantic. But if _Globigerinae_, and _Terebratula caput-serpentis_
and _Beryx_, not to mention other forms of animals and of plants, thus
bridge over the interval between the present and the Mesozoic periods,
is it possible that the majority of other living things underwent a
"sea-change into something new and strange" all at once?
[Footnote 1: See an article in the _Saturday Review_, for 1858, on
"Chalk, Ancient and Modern."]
6. Thus far I have endeavoured to expand and to enforce by fresh
arguments, but not to modify in any important respect, the ideas
submitted to you on a former occasion. But when I come to the
propositions touching progressive modification, it appears to me, with
the help of the new light which has broken from various quarters, that
there is much ground for softening the somewhat Brutus-like severity
with which, in 1862, I dealt with a doctrine, for the truth of which I
should have been glad enough to be able to find a good foundation.
So far, indeed, as the _Invertebrata_, and the lower _Vertebrata_ are
concerned, the facts and the conclusions which are to be drawn from
them appear to me to remain what they were. For anything that, as yet,
appears to the contrary, the earliest known Marsupials may have been
as highly organized as their living congeners; the Permian lizards
show no signs of inferiority to those of the present day; the
Labyrinthodonts cannot be placed below the living Salamander and
Triton; the Devonian Ganoids are closely related to _Polypterus_ and
to _Lepidosiren_.
But when we turn to the higher _Vertebrata_, the results of recent
investigations, however we may sift and criticise them, seem to me to
leave a clear balance in favour of the doctrine of the evolution
of living forms one from another. Nevertheless, in discussing this
question, it is very necessary to discriminate carefully between the
different kinds of evidence from fossil remains which are brought
forward in favour of evolution.
Every fossil which takes an intermediate place between forms of
life already known, may be said, so far as it is intermediate, to be
evidence in favour of evolution, inasmuch as it shows a possible road
by which evolution may have taken place. But the mere discovery of
such a form does not, in itself, prove that evolution took place by
and through it, nor does it constitute more than presumptive evidence
in favour of evolution in general. Suppose A, B, C to be three
forms, while B is intermediate in structure between A and C. Then the
doctrine of evolution offers four possible alternatives. A may have
become C by way of B; or C may have become A by way of B; or A and
C may be independent modifications of B; or A, B, and C may be
independent modifications of some unknown D. Take the case of the
Pigs, the _Anoplotheridae_, and the Ruminants. The _Anoplotheridae_
are intermediate between the first and the last; but this does not
tell us whether the Ruminants have come from the Pigs, or the Pigs
from Ruminants, or both from _Anoplotheridae_, or whether Pigs,
Ruminants, and _Anoplotheridae_ alike may not have diverged from some
common stock.
But if it can be shown that A, B, and C exhibit successive stages in
the degree of modification, or specialization, of the same type; and
if, further, it can be proved that they occur in successively
newer deposits. A being in the oldest and C in the newest, then the
intermediate character of B has quite another importance, and I should
accept it, without hesitation, as a link in the genealogy of C. I
should consider the burden of proof to be thrown upon anyone who
denied C to have been derived from A by way of B, or in some closely
analogous fashion; for it is always probable that one may not hit upon
the exact line of filiation, and, in dealing with fossils, may mistake
uncles and nephews for fathers and sons.
I think it necessary to distinguish between the former and the latter
classes of intermediate forms, as _intercalary types_ and _linear
types_. When I apply the former term, I merely mean to say that as
a matter of fact, the form B, so named, is intermediate between the
others, in the sense in which the _Anoplotherium_ is intermediate
between the Pigs and the Ruminants--without either affirming, or
denying, any direct genetic relation between the three forms involved.
When I apply the latter term, on the other hand, I mean to express the
opinion that the forms A, B, and C constitute a line of descent, and
that B is thus part of the lineage of C.
From the time when Cuvier's wonderful researches upon the extinct
Mammals of the Paris gypsum first made intercalary types known, and
caused them to be recognized as such, the number of such forms has
steadily increased among the higher _Mammalia_. Not only do we now
know numerous intercalary forms of _Ungulata_, but M. Gaudry's great
monograph upon the fossils of Pikermi (which strikes me as one of the
most perfect pieces of palaeontological work I have seen for a long
time) shows us, among the _Primates, Mesopithecus_ as an intercalary
form between the _Semnopitheci_ and the _Macaci_; and among the
_Carnivora, Hyaenictis_ and _Ictitherium_ as intercalary, or, perhaps,
linear types between the _Viverridae_ and the _Hyaenidae_.
Hardly any order of the higher _Mammalia_ stands so apparently
separate and isolated from the rest as that of the _Cetacea_; though
a careful consideration of the structure of the pinnipede _Carnivora_,
or Seals, shows, in them, many an approximation towards the still more
completely marine mammals. The extinct _Zeuglodon_, however, presents
us with an intercalary form between the type of the Seals and that of
the Whales. The skull of this great Eocene sea-monster, in fact, shows
by the narrow and prolonged interorbital region; the extensive union
of the parietal bones in a sagittal suture; the well-developed nasal
bones; the distinct and large incisors implanted in premaxillary
bones, which take a full share in bounding the fore part of the gape;
the two-fanged molar teeth with triangular and serrated crowns,
not exceeding five on each side in each jaw; and the existence of a
deciduous dentition--its close relation with the Seals. While, on
the other hand, the produced rostral form of the snout, the
long symphysis, and the low coronary process of the mandible are
approximations to the cetacean form of those parts.
The scapula resembles that of the cetacean _Hyperoodon_, but the
supra-spinous fossa is larger and more seal-like; as is the humerus,
which differs from that of the _Cetacea_ in presenting true articular
surfaces for the free jointing of the bones of the fore-arm. In the
apparently complete absence of hinder limbs, and in the characters of
the vertebral column, the _Zeuglodon_ lies on the cetacean side of the
boundary line; so that, upon the whole, the Zeuglodonts, transitional
as they are, are conveniently retained in the cetacean order. And the
publication, in 1864, of M. Van Beneden's memoir on the Miocene and
Pliocene _Squalodon_, furnished much better means than anatomists
previously possessed of fitting in another link of the chain which
connects the existing _Cetacea_ with _Zeuglodon_. The teeth are much
more numerous, although the molars exhibit the zeuglodont double fang;
the nasal bones are very short, and the upper surface of the rostrum
presents the groove, filled up during life by the prolongation of the
ethmoidal cartilage, which is so characteristic of the majority of the
_Cetacea_.
It appears to me that, just as among the existing _Carnivora_,
the walruses and the eared seals are intercalary forms between the
fissipede Carnivora and the ordinary seals, so the Zeuglodonts are
intercalary between the _Carnivora_, as a whole, and the _Cetacea_.
Whether the Zeuglodonts are also linear types in their relation to
these two groups cannot be ascertained, until we have more definite
knowledge than we possess at present, respecting the relations in time
of the _Carnivora_ and _Cetacea_.
Thus far we have been concerned with the intercalary types which
occupy the intervals between Families or Orders of the same class; but
the investigations which have been carried on by Professor Gegenbaur,
Professor Cope, and myself into the structure and relations of the
extinct reptilian forms of the _Ornithoscelida_ (or _Dinosauria_ and
_Compsognatha_) have brought to light the existence of intercalary
forms between what have hitherto been always regarded as very distinct
classes of the vertebrate sub-kingdom, namely _Reptilia_ and _Aves_.
Whatever inferences may, or may not, be drawn from the fact, it is now
an established truth that, in many of these _Ornithoscelida_, the hind
limbs and the pelvis are much more similar to those of Birds than
they are to those of Reptiles, and that these Bird-reptiles, or
Reptile-birds, were more or less completely bipedal.
When I addressed you in 1862, I should have been bold indeed had I
suggested that palaeontology would before long show us the possibility
of a direct transition from the type of the lizard to that of the
ostrich. At the present moment we have, in the _Ornithoscelida_, the
intercalary type, which proves that transition to be something more
than a possibility; but it is very doubtful whether any of the genera
of _Ornithoscelida_ with which we are at present acquainted are the
actual linear types by which the transition from the lizard to the
bird was effected. These, very probably, are still hidden from us in
the older formations.
Let us now endeavour to find some cases of true linear types, or forms
which are intermediate between others because they stand in a direct
genetic relation to them. It is no easy matter to find clear and
unmistakable evidence of filiation among fossil animals; for, in order
that such evidence should be quite satisfactory, it is necessary that
we should be acquainted with all the most important features of the
organization of the animals which are supposed to be thus related, and
not merely with the fragments upon which the genera and species of the
palaeontologist are so often based. M. Gaudry has arranged the species
of _Hyaenidae, Proboscidea, Rhinocerotidae_, and _Equidae_ in their
order of filiation from their earliest appearance in the Miocene epoch
to the present time, and Professor Rütimeyer has drawn up similar
schemes for the Oxen and other _Ungulata_--with what, I am disposed
to think, is a fair and probable approximation to the order of nature.
But, as no one is better aware than these two learned, acute, and
philosophical biologists, all such arrangements must be regarded as
provisional, except in those cases in which, by a fortunate accident,
large series of remains are obtainable from a thick and wide-spread
series of deposits. It is easy to accumulate probabilities--hard
to make out some particular case in such a way that it will stand
rigorous criticism.