GENERAL ZOOLOGICAL WORK
In the course of the preceding chapters numerous more or less incidental
references have been made to the contributions of Sir William Flower to
biological literature, as well as to his many improvements in museum
organisation and arrangement. The more detailed discussion of these
has, however, been reserved for the present and succeeding chapters, of
which the first two are devoted to the zoological and the third to the
anthropological side of his work, while in the fourth his views in regard
to museums and certain other subjects are taken into consideration.
Regarding the general scientific work of Flower, it must be confessed at
the outset that this is characterised in the main by its conscientious
carefulness and exactness, rather than by brilliancy of thought,
conception, or style. Great attention to detail, both as regards the work
itself and in reference to authorities (which were always most carefully
verified), is indeed one of the leading features of his labours; but
there is no epoch-making discovery or comprehensive generalisation which
can be associated with his name. In connection with his careful attention
to small and apparently trivial points of detail, the following passage
from Professor Ray Lankester’s obituary notice in _Nature_ may be
appropriately quoted:—
“He did his own work with his own hands, and I have the best reason to
know that he was so deeply shocked and distressed by the inaccuracy
which unfortunately crept into some of the work of his distinguished
predecessor, Owen, through the employment of dissectors and draughtsmen,
whose work he did not sufficiently supervise, that he himself determined
to be exceptionally careful and accurate in his own records and notes.”
In another passage of his notice the same writer observes that:—
“Caution and reticence in generalisation certainly distinguish all
Flower’s scientific writings. Whilst he was on this account necessarily
not known as the author of stirring hypotheses, his statements of fact
gained in weight by his reputation for judgment and accuracy.”
Flower’s zoological studies related entirely to the vertebrates and
almost exclusively to mammals, although he devoted a few papers, such as
the one on the gular pouch of the great bustard, and that on the skull
of a cassowary, to birds. Other groups, I believe, he never touched. In
the earlier years of his scientific career, at anyrate, his labours were
in the main devoted to the anatomical aspect of zoology, such subjects
as the dentition, osteology, and the structure and characters of the
brain and viscera claiming a much larger share of his attention than was
bestowed on the myology. In latter years the classification of the major
groups of the mammalia received much attention from Flower. Not that he
was in any way what is nowadays called a systematist in zoology, that is
to say, he took no active part in describing new species (not to mention
sub-species, which had scarcely begun to be recognised by naturalists in
his day), or the redefining of generic groups, and other work of this
nature. Indeed, as mentioned in the chapter devoted to his career at
the College of Surgeons, he was extremely conservative in this respect,
and strongly opposed to the modern fondness for small generic groups,
and also for changing generic names which, from long association, have
come almost to be regarded as household words and integral parts of the
English language. The substitution of the name _Procavia_, for _Hyrax_,
the familiar title of the Klipdass, was, for instance, very repugnant to
him, although loyally accepted when found to be coming into general use.
As a matter of fact, so far as my information goes, with the exception
of certain whales and dolphins, and one extinct sea-cow (_Halitherium_),
Flower never named a new species of animal, nor, I think, did he ever
propose a new generic term. Indeed, so opposed was he to any interference
with names of the latter description in general use, that when several
such were replaced by alternative ones in the _Study of Mammals_, it was
expressly stipulated by him that the responsibility for such substitution
should rest solely with the present writer.[3]
The modern system of forming trinomials to indicate the local races,
or sub-species, of mammals (as exemplified by _Giraffa camelopardalis
rothschildi_ and _Giraffa camelopardalis capensis_ for two of the local
phases of the species of giraffe typified by _G. camelopardalis_ of the
Egyptian Sudan and Abyssinia), was practically in its infancy during the
active life-time of Flower, and it is doubtful how he would have approved
of the extent to which it has been subsequently carried. Nevertheless,
that he appreciated the practice of recognising minute local differences
of colour, size, etc., in the same species of mammals is evident from
an incident within the writer’s own knowledge, which occurred at the
Natural History Museum, when a tray containing the local phases of one
of the species of the small squirrel-like rodents known as chipmunks
was submitted to his notice; his remark being that such variations from
a common type ought in nowise to be ignored, if we wished to make our
knowledge of animals anything like complete, and that the simplest way of
indicating such differences was to assign them distinct names.
In a general way, however, it may be said that Sir William’s sympathies
were with the wider and more philosophical aspects of zoology rather
than with the details of specific and sub-specific distinction (which,
by the way, have scarcely any more right to be regarded as real
philosophical science than has stamp-collecting)[4]; and that, from a
systematic standpoint, his interest was very largely concentrated on the
relationships existing between the mammals of to-day and their extinct
predecessors. Several of his lectures and papers, and one especially of
his separate works (that on _The Horse_) were indeed devoted to this
aspect of the subject; and on every possible occasion he emphasised his
conviction of the necessity of studying (and arranging in museums) living
and extinct mammals together, if we wish to make our science really
practical.
As a matter of fact he had the strongest possible objection to the
recognition of “palæontology” as a science apart from zoology, and he
even went so far as to mildly rebuke (in his own inimitably courteous and
gentle manner) the present writer, for venturing to offer to the public
a volume on that subject. To a great extent, no doubt, he was perfectly
right in this contention, although there are points of view from which
“palæontological” works are decidedly convenient, even if their existence
and production cannot be logically justified.
As regards the particular groups of mammals (other than man) in which
Flower was more especially interested, there can be no doubt that the
Cetacea (whales and dolphins) occupied the first position. And on this
subject he was undoubtedly one of the first authorities, his only
possible rivals in this country, at anyrate, being Sir William Turner and
Professor Struthers. Next to this group came, perhaps, the marsupials,
in which a most important discovery was made by Flower in regard to the
succession and replacement of the teeth.
Not even the most sympathetic of biographers would attempt for one
instant to assume that his hero—if a zoologist—could by any possibility
be infallible; and it has to be recorded that many changes and amendments
have had to be made in Flower’s conclusions. Perhaps, indeed, Sir William
has been to some extent especially unfortunate in this respect, owing to
the extreme imperfection of the state of our palæontological (I must use
the objectionable word) knowledge at the date when much of his best work
was accomplished. At that time, in spite of the enormous and valuable
results achieved by Cuvier, Owen, and others, mammalian palæontology
may be said to have been in its infancy compared to its present state;
the wonderful discoveries in North and South America being then either
unknown or only partially revealed, and the same being the case with
regard to those made known by the working of the phosphorite beds in
Central France.
These and other discoveries have, for instance, totally revolutionised
our ideas with regard to the affinities of the different families of the
modern Carnivora, and have thus led to considerable modifications of the
views entertained by Flower as to the relationships of the members of
this group.
Moreover, there is another important factor which has to be taken into
consideration. At the time when Sir William wrote his celebrated memoir
on the Carnivora, the effects of what is now universally known among
zoologists as “parallelism in development” were quite unrecognised.
By “parallelism” (to abbreviate the expression) is meant, it may be
explained, a remarkable tendency which undoubtedly exists among animals
of markedly diverse origin to become more or less like one another in
at least one important structural feature, when living under similar
physical conditions, or specially adapted for similar modes of existence.
Not unfrequently this structural resemblance, when closely examined, is
found to be less close than might at first sight have seemed to be the
case; the adaptation having been brought about by the modification of
structures originally more or less dissimilar towards a common type. In
other words, the same goal has been reached by two different routes.
An excellent example of this is offered by the development of
“cannon-bones” in the lower portion of the limbs of the members of the
horse tribe on the one hand and those of the deer and antelopes on the
other; the object of this lengthening and strengthening of this part
of the limb being in both instances the attainment of increased speed.
Whereas, however in the one instance the cannon-bone is formed from one
original element, in the other it is the result of the fusion of two
such elements. In this case, indeed, the difference in the structure of
this part of the skeleton in the two groups is so apparent as to leave
no reasonable doubt as to the remoteness of the affinity between their
respective ancestors. There is, however, a certain group of extinct South
American hoofed mammals in which the cannon-bone corresponds exactly
in origin and structure with that of the horse, from which it might be
assumed that the two animals were closely related, whereas, from other
evidence, we know that they are widely sundered. Approximately similar
structures are therefore in many instances far from being indications of
genetic affinity between the animals in which they respectively occur.
Before the occurrence of this parallelism was recognised by naturalists
as an important factor in their development, such resemblances were,
however, frequently regarded as indications of a common parentage, so
that animals which had comparatively little to do with one another were
brigaded as members of the same assemblage.
With these preliminary remarks, we may proceed to a general survey of
Sir William’s zoological work. It has, however, been found convenient to
relegate the consideration of his numerous memoirs on the Cetacea to the
next chapter, by which means their connection will be made more apparent
than if they were discussed among those on other sections of zoology.
The first zoological paper (and indeed the first scientific work of
any description) published by Flower seems to have been that on the
dissection of one of the African lemurs belonging to the genus _Galago_,
which appeared in the Zoological Society’s _Proceedings_ for 1852, and
serves to prove, as mentioned in the first chapter, that the author was
at that time holding the post of Curator of the Museum of the Middlesex
Hospital. The paper itself is of little importance, dealing only with the
structure of the muscles and viscera of the species in question.
The next paper on the list, which appeared in the same journal for 1860,
was also written during this part of Flower’s career; it is one of the
few devoted to the anatomy of birds, and describes the gizzard of the
Nicobar pigeon and other graminivorous species.
About this time Flower began to devote his attention to the mammalian
brain; his first contribution on this subject being “Observations
on the Posterior Lobes of the Cerebrum of the Quadrumana, with the
Description of the Brain of a _Galago_,” of which an abstract appeared
in the _Proceedings_ of the Royal Society of London for 1860, although
the complete memoir was not published till 1862, in the _Philosophical
Transactions_. The date of publication of the abstract proves that these
studies were commenced, and the memoir in question completed, before (and
not, as stated by Professor M’Intosh,[5] after) the author’s appointment
to the Conservatorship of the Museum of the College of Surgeons, which
did not take place till the year 1861. The brain of another monkey was
also described in a paper on the anatomy of a South American species then
known as _Pithecia monachus_, which appeared in the Zoological Society’s
_Proceedings_ for 1862. In the following year (1863) he published, in
the _Natural History Review_, a still more important communication,
dealing with the brain of the Malay siamang (_Hylobates syndactylus_),
one of the man-like apes, in which it was shown that in this species
(and probably therefore in gibbons generally) the posterior part of the
cerebrum, or main division of the brain, overlapped the cerebellum, or
hind brain, to an even less degree than in the American howling-monkeys,
which had hitherto been regarded as the lowest members of the group, so
far as the feature in question was concerned. That such a feature should
occur in one of the highest groups of apes was certainly a remarkable
and unexpected discovery. Yet another contribution to the same subject
was made in 1864, when a paper appeared in the Zoological Society’s
_Proceedings_ on the brain of the red howling-monkey, then known as
_Mycetes seniculus_, but of which the generic title is changed by many
modern naturalists to _Alouata_.
The earlier memoirs of this series published (in the _Philosophical
Transactions_), writes Professor M’Intosh in the _Scottish Review_ for
1900, “formed important evidence in the discussions which took place
between Owen and Huxley in regard to the posterior lobe of the brain,
the posterior cornu, and the hippocampus minor.” Professor Owen, at the
Cambridge Meeting of the British Association in 1862, maintained, from
specimens of the human brain in spirit, and from a cast of the interior
of the gorilla’s skull, that in man the posterior lobes of the brain
overlapped the cerebellum, whereas in the gorilla they did not; that
these characters are constant, and therefore he had decided to place man,
with his overlapping posterior lobes, the existence of a posterior horn
in the lateral ventricle, and the presence of a hippocampus minor in
the posterior horn, under the special division Archencephala. Moreover,
he grouped with these features the distinctive characters of the foot
of man, and showed how it differed from that of all monkeys. Flower’s
accurate investigations enabled Huxley to substantiate his antagonistic
position to Owen’s doctrines, viz., that these structures, instead of
being the attributes of man, are precisely the most marked cerebral
characters common to man with the apes. Huxley also asserted that the
differences between the foot of man and that of the higher apes were of
the same order, and but slightly different in degree from those which
separated one ape from another.
The result of this controversy was the overthrow (except in the mind
and works of its author) of Owen’s separation of man on the one hand
as the representative of a primary group—the Archencephala; and of
apes, monkeys, Carnivora, Ungulates, Sirenians, and Cetaceans on the
other hand, as forming a second group—the Gyrencephala.[6] As will
be seen from the above quotation, this result was very largely due to
the work of Flower, although it was brought into prominent notice by
the superior fighting powers of Huxley, who was also an older, and at
the time at anyrate, a better-known man. It may be added that Flower
himself subsequently abandoned the use of the term “Quadrumana,” as
distinguishing apes and monkeys on the one hand from man, as “Bimana,”
on the other, and brigaded all altogether under their Linnæan title
“Primates.”
The contributions of Flower to our knowledge of (and, it may be added, to
the clearing up of misconceptions in regard to) the mammalian brain, was,
however, by no means confined to the Primates (man, apes, monkeys, and
lemurs). On the contrary, his researches were of equal—if not indeed of
more—importance with regard to the structure of that organ in the lower
groups of the class, namely the marsupials and the monotremes (duckbill
platypus and spiny ant-eater).
In the well-known Reade Lecture of 1859, Professor Owen expressed himself
as follows with regard to the brain of the two groups last mentioned:—
“Prior to the year 1836, it was held by comparative anatomists that the
brain in mammalia differed from that in all other vertebrate animals by
the presence of the large mass of transverse white fibres called ‘corpus
callosum’ by the anthropotomist; which fibres, overarching the ventricles
and diverging as they penetrate the substance of either hemisphere of
the cerebrum, bring every convolution of the one into communication with
those of the other hemisphere, whence the other name of this part—the
‘great commissure.’ In that year I discovered that the brain of the
kangaroo, the wombat, and some other marsupial quadrupeds, wanted the
‘great commissure’; and that the cerebral hemispheres were connected
together, as in birds, only by the ‘fornix’ and ‘anterior commissure.’
Soon afterward I had the opportunity of determining that the same
deficiency of structure prevailed in the _Ornithorhynchus_ (duckbill) and
_Echidna_ (spiny ant-eater).”
Owen’s conclusions with regard to the absence of the great connecting
band of fibres between the hemispheres of the marsupial brain were
first published in the _Philosophical Transactions_ for 1837; those,
with regard to the same lack in the monotremes, being added in Todd’s
_Cyclopædia of Anatomy and Physiology_, Article “Monotremata.” In the
latter article it was also stated that the brain of the echidna was
further distinguished from that of other mammals by the circumstance
that whereas in the latter the portion of the brain known as the optic
lobes consists of four lobes (_corpora quadrigemina_), in the echidna and
duckbill there are only a pair of such lobes (_corpora bigemina_.)
In consequence of this supposed lack of the corpus callosum in their
brains, Owen separated the marsupials and monotremes from other mammals
in a primary group by themselves, under the title of Lyencephala.
Flower’s attack on these conclusions was commenced by a paper which
appeared in the Zoological Society’s _Proceedings_ for 26th January 1864,
entitled “On the Optic Lobes of the Brain of the Echidna,” in which it
was conclusively demonstrated that these structures resembled those of
the higher mammals in being four-lobed.
More important still was his memoir “On the Commissures of the Cerebral
Hemispheres of the Marsupialia and Monotremata, as compared with those
of the Placental Mammals,” which was published in the _Philosophical
Transactions_ of the Royal Society for 1865. In this was shown, it was
thought, the existence in both monotremes and marsupials of a distinct,
although very small, corpus callosum connecting the two hemispheres of
the brain; the anterior commissure, which in the higher mammals is the
smaller connecting band, being in this instance much the larger.
Recent researches have, however, tended to show that Owen was after all
right in denying the existence of a corpus callosum in the latter groups.
Even allowing for this correction, the result of this important paper was
to discredit among all zoologists capable of forming an adequate opinion
on the subject Owen’s proposed fourfold division of the Mammalia into
Lyencephala, Lissencephala, Gyrencephala, and Archencephala. And these
terms have now completely disappeared from zoological literature.
In those days it required no considerable amount of courage to attack
a man of Owen’s established social and scientific position on an
important subject like this; and Flower’s triumph was therefore the more
conspicuous. Of course such of these discoveries as are valid, if they
had not been made by him, would have been made later on by somebody else,
as they merely required accurate dissection and observation. But this
may be said of every discovery of a like nature; and Flower is entitled
to all credit for having worked out the subject in the way he did. It
may be added, that, with our present knowledge of mammalian morphology,
a classification based on the characters of the brain is manifestly
based on a misconception from first to last; the degree of development
and specialisation of that organ being purely adaptive features, and
therefore not dependent upon structural relationships. Had Owen’s
classification been maintained, it would have been necessary to assign
the primitive Carnivora and Ungulata to a group quite apart from the one
containing their existing representatives.
In the light of modern research, it cannot now be held that the result
of Flower’s investigations in this direction was to demonstrate the
existence of a corpus callosum to the brain in all the members of the
mammalian class.
In another paper, dealing with the brain of the Javan loris, published
in the _Transactions_ of the Zoological Society, Flower made a further
contribution to the study of this part of the organism. Previous to the
appearance of the memoir on the marsupial and monotreme brain, Flower had
published, in the _Natural History Review_ for 1864, one on the number of
cervical vertebræ in the Sirenia (manati and dugong). Apart from several
papers on whales and dolphins, which, as already mentioned, are reserved
for consideration in a later chapter, the next noteworthy zoological
contribution from Flower’s pen appears to be one on the gular pouch of
the great bustard, published in the Zoological Society’s _Proceedings_
for 1865. This pouch, which, it may be observed is confined to the
cock-bird, and inflated during the breeding season, is a very remarkable
structure, which has recently been described in greater detail by Mr. W.
P. Pycraft.
Two years later (1867), Flower contributed to the same journal a paper
on the anatomy of the West African chevrotain, _Hyomoschus aquaticus_,
or, as it is now called, _Dorcatherium aquaticum_. The specimen on
which the paper was based was the first of its kind which had ever been
dissected—at least in this country; and the result of its examination
was to confirm the view that the mouse-deer, or chevrotains, cannot be
included among the true ruminants, or Pecora, but rather that they form
a group (Tragulina), in many respects intermediate between the latter
and the pigs and hippopotamuses, or Suina. To the essential difference
between the chevrotains and the musk-deer, which have often been
confounded, Flower was very fond of recurring in his later writings.
About the year 1866 Sir William began to turn his attention to the teeth
of mammals, more especially as regards the mode in which the milk or baby
series is succeeded by the permanent teeth, and the general homology of
the milk with the permanent, and of the individual teeth of both series
with one another. As the result of these investigations he published
during the next few years the following papers on this subject. First and
most important, one on the development and succession of the teeth of
marsupials, which appeared in the _Philosophical Transactions_ for 1867.
In the following year he delivered before the British Association at
Norwich a paper entitled “Remarks on the Homologies and Relation of the
Teeth of the Mammalia,” which was published in the _Journal of Anatomy
and Physiology_ for the same year. In that year he also published, in
the _Proceedings_ of the Zoological Society, an account of the homology
and succession of the teeth in the armadillos. A general sketch from his
pen of the dentition of mammals was published in the _British Medical
Journal_ for 1871, while in the _Transactions_ of the Odontological
Society for the same year, appeared a paper on the first, or milk,
dentition of the Mammalia.
By far the most important of this series of papers is undoubtedly the
one on the succession and homologies of the teeth in the marsupials or
pouched mammals; and it is the one which contains, perhaps, the most
noteworthy discovery made by Flower.
Owen had previously pointed out that marsupials differ from ordinary
placental mammals in having four (in place of three) pairs of cheek-teeth
at the hinder part of the series which have no milk, or deciduous,
predecessors, and are therefore, according to the usual rule, to be
regarded as true molars, in contradiction to premolars, in which such
deciduous predecessors are generally developed. He considered, however,
that all the premolars in the kangaroo (and therefore presumably in other
marsupials) as well as the incisors or cutting teeth, and the canines
or tusks, were preceded by milk-teeth. Flower, on the other hand (who
it is only just to add had a much fuller series of specimens of young
marsupials on which to work than was available to Owen), was enabled
to show that in the Marsupialia only one pair of teeth in each jaw, at
most, is preceded by a milk-tooth. The tooth, in question, is the fifth
from the posterior end of the series, and whereas in the adult animal
it differs in character from those behind it, its deciduous predecessor
resembles the latter. The replacing tooth was further considered to
correspond with the fourth or last premolar of placental mammals, while
the replaced tooth was regarded as the only one in the entire series
corresponding to the milk-teeth of placental mammals. This view rendered
it necessary, of course, to regard all the four pairs of cheek-teeth
behind this abnormal one as corresponding to the true molars of
placentals, as had been done by Owen, thus making, as already mentioned,
marsupials to differ from ordinary placentals by possessing four instead
of three pairs of these teeth.
Before proceeding to notice an amendment which has been proposed in
regard to the homology of the one successional tooth of the marsupials,
certain other features connected with it and its predecessor discussed by
Flower may be briefly mentioned. He noticed, to quote from an admirable
epitome of his observations on this point, drawn up by Professor M’Intosh
in the _Scottish Review_ for 1900, “that there were considerable
differences in the various genera as to the relative period of the
animal’s life at which the fall of the temporary molar and the evolution
of its successor takes place. In some, as in the rat-kangaroos, it is one
of the latest, the temporary tooth retaining its place and its functions
until the animal has nearly, if not quite, reached its full growth, and
is not shed until all the other teeth are in position and use. On the
other hand, in the Tasmanian wolf the temporary tooth is very rudimentary
in size and form, and is shed or absorbed before any other teeth enter
the gum. Anterior to the period of Sir William Flower’s communication,
mammals had been, in regard to the succession of their teeth, divided
into two groups—the Monophyodonts, or those that generate a single
series of teeth, and the Diphyodonts, or those that develop two sets
of teeth, but, as he pointed out, even in the most typical Diphyodonts
the successional process does not extend to the whole of the teeth,
always stopping short of those situated most posteriorly in each series.
The pouched animals (marsupials), he stated, occupied an intermediate
position, presenting, as it were, a rudimentary diphyodont condition, the
successional process being confined to a single tooth on each side of
each jaw.”
All this is unexceptionable. Flower, however, went further than this, and
claimed that the true molar teeth of mammals correspond serially with the
permanent premolars, canines, and incisors, and not with their deciduous
predecessors. And he therefore urged (as indeed must be the case on these
premisses) that the whole dentition of adult marsupials corresponds with
the permanent dentition of placentals. A further inference from this
is that the milk-teeth, instead of being an original development, may
rather be a set superadded to meet the temporary needs of mammals whose
permanent set is of a highly complex type.
To review the objections which have been raised against these views would
be entering on a very difficult question, and one in regard to which
uniformity of opinion by no means exists among naturalists even at the
present day. It may be mentioned, however, that from the circumstance of
the later milk-premolars resembling (as was noticed by Flower in the case
of the one tooth replaced in marsupials) the true molars rather than the
permanent premolars, it has been suggested that the milk-dentition is
serially homologous with the true molars. And on this view, the entire
dentition of marsupials (with the exception of the one replacing tooth)
corresponds to the milk-dentition of placentals. Possibly, however, the
larger number of incisors which distinguish many of the carnivorous
marsupials from the placentals may be due to the development of teeth
belonging to the permanent series with those of the milk-set, and both
persisting together throughout life. Be this as it may, it is evident,
on the above view of the serial homology of their dentition, that
marsupials, instead of as Flower supposed, showing the commencement of a
milk-dentition, really exhibit the decadence of the permanent series.
In this respect they display a precise similarity to the modern
elephants, as indeed was pointed out by Flower in his original paper,
although on a false premiss, for he at that time regarded the anterior
cheek-teeth of the elephant as the representatives of the permanent
premolars, whereas they really correspond with the milk-premolars.
One objection has indeed been raised with regard to the identification of
the adult marsupial dentition with the milk-set of placentals, namely,
the existence in certain marsupialia of rudimentary teeth belonging to
an earlier set than the one functionally developed. This has been got
over by regarding these rudimentary germs as the representatives of a
prelacteal series.
Passing on to another point, it has to be noticed that exception has also
been taken to Flower’s view that the replacing tooth of marsupials and
its deciduous predecessor correspond to the fourth, or last premolar of
placentals. The question has been discussed in considerable detail in
the Zoological Society’s _Proceedings_ for 1899 by the present writer,
who had for material the dentition of certain extinct South American
mammals quite unknown to science at the time Flower’s paper was written.
The result of these comparisons was to render it evident, in the present
writer’s opinion, that the replacing tooth of the marsupials corresponds
to the third, instead of to the fourth, premolar of placentals. From
this it follows that marsupials agree with placentals in possessing only
three pairs of true molars; the first of the four teeth in the former
behind the replacing tooth being the last milk-premolar (which is never
replaced) instead of, as supposed by Flower, the first true molar. This
conclusion, as pointed out by the present writer in the paper referred
to above, had really been arrived at years previously by Owen, who also
believed the replacing tooth to correspond to the third premolar of
placentals.
In thus bringing marsupials into line with placentals as regards their
dentition, this later interpretation accords well with recent discoveries
in regard to other parts of the organisation of the former animals.
It should, however, be mentioned that the newer view is by no means
accepted by all zoologists, although it has received the support of
the well-known American paleontologist, Dr. J. L. Wortman,[7] who is
specially qualified to form a trustworthy opinion on a point of this
nature.
Finally, whatever be the eventual verdict as to the serial homology of
the marsupial dentition as a whole, and also as to that of the replacing
premolar, Flower must always be credited with the discovery that
marsupials replace only a single pair of teeth in each jaw by vertical
successors.
The other papers on dentition referred to above as having been written
by Flower about the same time are, although interesting in their way,
of far less importance than the one published in the _Philosophical
Transactions_. Indeed the one read before the British Association in 1868
and published in the _Journal of Anatomy and Physiology_ for the same
year, is little more than a recapitulation of the results arrived at in
the former.
The paper on the development and succession of the teeth in the
armadillos, published in the Zoological Society’s _Proceedings_ in
1868, is, on the other hand, of considerable interest on account of its
confirming the fact first mentioned by the French zoologist, Professor
Paul Gervais, but generally overlooked by subsequent writers up to that
time, that the common nine-banded armadillo (_Tatusia peba_) differs from
its relatives in replacing some of its teeth by vertical successors. This
at the time was an unexpected feature in any member of the so-called
Edentate mammals; and tended further to break down the supposed hard and
fast distinction between monophyodonts and diphyodonts.
Closely connected with the subject of dentition is a paper on “The
Affinities and Probable Habits of the Extinct Marsupial, _Thylacoleo
carnifex_ (Owen),” communicated by Flower to the Geological Society of
London in 1868, and published in the _Quarterly Journal_ of that body
for the same year. After alluding to the paper on marsupial dentition,
Professor Ray Lankester, in his obituary notice of Sir William in
_Nature_, of 13th July 1899, observes of the communication under
consideration that—“The next most striking discovery which we owe to
Flower seems to me to be the complete and convincing demonstration that
the extinct marsupial, called _Thylacoleo carnifex_ by Owen, was not a
carnivore, but a gnawing herbivorous creature like the marsupial rats and
the wombat—a demonstration which has been brought home to the eye even of
the unlearned by the complete restoration of the skull of _Thylacoleo_ in
the Natural History Museum by Dr. Henry Woodward.”
If we are to believe later authorities, Flower’s demonstration of the
herbivorous nature of the creature in question was by no means so
“complete and convincing” as the learned Professor would have us believe;
but of this anon.
The first important paper on _Thylacoleo_, which was a creature of
the approximate size of a jaguar, whose remains are met with in the
superficial formations of Australia, was one by Owen, published in the
_Philosophical Transactions_ for 1859. From the general characters of the
skull (which was at that time only known by fragments), and especially
from the rudimentary condition of the hinder cheek-teeth and the enormous
size of the secant replacing premolar, which bears a certain superficial
resemblance to the carnassial tooth of the cats, its describer was led
to the conclusion that _Thylacoleo_ was a marsupial carnivore, and “one
of the fellest and most destructive of predatory beasts.” Probably
Owen’s views at this time were, that the creature had its nearest
living relatives in the members of the Australian family _Dasyuridæ_,
such as the Tasmanian devil (_Sarcophilus ursinus_), and that it bore a
relationship to the existing carnivorous marsupials somewhat similar to
that presented by a lion to a dog. At this time there was no evidence to
show whether the large teeth near the front of the jaw, the existence of
which was indicated in the original specimen merely by its empty socket,
was a canine or an incisor; and though Owen was inclined to regard it
as the former, he admitted that it might be an incisor, in which event
he recognised that the affinities of the animal would be more with
the herbivorous, or diprotodont section of the marsupials, and more
especially the phalangers, or so-called opossums of the colonists. This
is clearly indicated by the following sentence appended by Sir Richard
to his description:—“If, however, this be really the foremost tooth
of the jaw, it would be one of a pair of terminal incisors according
to the marsupial type exhibited by the _Macropodidæ_ (kangaroos) and
_Phalangistidæ_ (phalangers).”
In 1866, after receiving additional specimens from Australia, Owen
was enabled to describe the greater part of the skull and the entire
dentition of _Thylacoleo_. The large anterior teeth were clearly
recognised to be incisors, which, in Owen’s opinion, “proved the
_Thylacoleo_ to be the carnivorous modification of the more common and
characteristic type of Australian marsupials, having the incisors of
the lower jaw reduced to a pair of large, more or less procumbent and
approximately conical teeth, or ‘tusks.’” Not only did the additional
evidence serve to confirm Sir Richard in his view of the carnivorous
propensities of _Thylacoleo_, but he considered that in this extinct form
we have “the simplest and most effectual dental machinery for predatory
life and carnivorous diet known in the mammalian class. It is the extreme
modification, to this end, of the diprotodont type of marsupialia.”
Beyond, however, admitting its affinities with the diprotodonts, Sir
Richard Owen does not appear in this later paper to have regarded
_Thylacoleo_ as a near relative of any of the existing forms; but in the
article on “Paleontology” in the eighth edition of the _Encyclopædia
Britannica_, published in 1859, he seems to have considered it allied to
_Plagiaulax_ of the Purbeck strata of Dorsetshire, which had been shown
by Dr. Hugh Falconer to be probably of herbivorous habits.
Sir William Flower, in the aforesaid paper in the Geological Society’s
_Quarterly Journal_ for 1868, while agreeing with Owen that _Thylacoleo_
was related to the diprotodont rather than to the polyprotodont
carnivorous marsupials, differed from the conclusion that it was a
carnivore. While the large cutting premolar teeth were considered by
Owen to resemble the carnassial teeth of a lion, Flower was struck by
their similarity to the corresponding teeth of the rat-kangaroos and
the phalangers. After discussing the other teeth, he concluded that “in
the number and arrangement of these teeth ... _Thylacoleo_ corresponds
exactly with the modern families _Macropodidæ_ and _Phalangistidæ_, and
differs completely from the carnivorous marsupials.”
After alluding to the small size of the brain-cavity and the large
space for the attachment of the powerful muscles which worked the lower
jaw, and suggesting that these features may be only to be expected in
a large form as compared with the smaller members of the same group,
Flower concluded that the habits of all species with the same general
type of dentition must necessarily be similar. And, on these premisses,
it was urged that _Thylacoleo_ must in all probability have been a
vegetable-feeder. The large premolar may seemingly have been “as well
adapted for chopping up succulent roots and vegetables, as for dividing
the nutritive fibres of animal prey.” It is further suggested that the
nutriment of _Thylacoleo_ “may have been some kind of root or bulb; it
may have been fruit; it may have been flesh.” While in conclusion it is
argued that the organisation of the animal did not countenance the idea
of its preying on the large contemporary marsupials.
Omitting reference to Owen’s reply to this reversal of his conclusions,
and also to certain comments and additions to the arguments by other
writers, we may pass on to a paper by Dr. R. Broom, published in the
_Proceedings_ of the Linnean Society of New South Wales for April 1898,
and entitled “On the Affinities and Habits of _Thylacoleo_.”
In this the author admits that the animal in question, as suggested
by Owen in his second paper, and more fully determined by Flower, was
undoubtedly a diprotodont, and that it was nearly allied to the modern
phalangers. With the latter it is indeed closely connected by the
recently discovered extinct _Burramys_, which differs from the existing
members of that group by the large size of the secant premolar.
After discussing numerous points in connection with the problem,
Dr. Broom states that those who believe _Thylacoleo_ to have been
carnivorous, “evidently consider that the molars have been reduced
through their functions being taken up by the large premolars. But could
the large premolars take up the molar function—could they grind? Even
those who favour the idea of _Thylacoleo_ being a vegetable-feeder, admit
that the premolars were cutting teeth, and the difficulty of imagining
a herbivorous animal without grinders is got over by supposing that its
food was of a soft or succulent nature.”
But for the creature to have lived on succulent roots and bulbs, the
vegetation of that part of Australia where it lived must, urges Dr.
Broom, have been quite different from what it is at the present day;
and we have no justification for assuming any such change to have taken
place. Moreover, an animal that could only slice, and not grind up,
vegetable food, could apparently subsist only on ripe fruit, and such is
to be met with in Australia only at one season of the year, when, owing
to the abundance of frugivorous mammals, little, if any, is allowed to
fall to the ground.
“It is probably however,” adds Dr. Broom, “unnecessary to discuss further
what food _Thylacoleo_ could possibly have obtained, when we have, as I
hold with Owen, the most satisfactory proof from its anatomical structure
as to what food it did obtain. It must be admitted that _Thylacoleo_
had enormous temporal muscles, and it is perfectly certain that such
muscles would not have been developed unless the animal required them.
For what could such powerful muscles be required? Most certainly not for
slicing fruits or succulent roots and bulbs, nor would they be required
even for the slicing of fleshy fibres. Temporal muscles are chiefly used
apparently for closing the jaws more or less forcibly from the open
position, while for the more complicated movements of mastication it is
the masseter and pterygoid muscles that are chiefly used. Hence in all
carnivorous animals the temporals are largely developed and the masseters
more feebly, because the killing process requires a very forcible closing
of the jaws, and the work to be done by the premolars and molars is
comparatively little. In herbivorous animals the conditions are reversed.
The jaws are here rarely required to be opened widely or to be closed
with any great force, while a very large amount of grinding work has to
be done; hence the temporals are rarely much larger than the masseters,
and often very much smaller. When we look at _Thylacoleo_, we find not
only the enormous temporals and only moderate masseters, but everything
else about the skull seems to be built on carnivorous lines. Owen has
shown the wonderful similarity which exists between the molar machinery
in _Thylacoleo_ and the lion, and it is hard to conceive as possible any
other cause giving rise to such a specialisation in _Thylacoleo_ than
that which led to a similar specialisation in the cat tribe. Another
most striking feature is to be seen in the condition of the incisors.
Leaving out of consideration the mode of implantation and structure of
the teeth—both confirmatory of the carnivorous hypothesis—there is one
point which appears to me absolutely conclusive on the subject. Unless
Owen’s figures are altogether unreliable, the lower incisors are quite
unlike those of the herbivorous diprotodonts. In such typical forms as
the wombat, the koala, the kangaroo, and the phalanger, though there are
different modifications of the arrangement, we have the lower incisors
meeting the upper, and forming with them an instrument for biting
through a moderately tough, fibrous tissue, and even in the very small
diprotodonts, so far as I am aware, the lower incisors always meet and
work against the upper. But in _Thylacoleo_ we have powerful pointed
incisors which do not meet, but overlap. Though technically incisors,
they are not intended to incise, but to pierce and tear. Such powerful
pointed and overlapping teeth, though easily explained on the theory
that they were intended to kill and tear animal prey, were never surely
provided merely to pierce succulent vegetables or ripe fruit. It might of
course be argued that the incisors were used as weapons of defence, as
apparently are the canines in the baboon; but against this idea is the
objection that the incisors were put to some use which wore them down and
blunted them more rapidly than would be the case if they were chiefly
used on the rare occasions when the animal had to defend itself; and
furthermore, were such the case, the temporals would not require to be
greatly developed.
“There is thus, in my opinion, no other conclusion tenable than that
_Thylacoleo_ was a purely carnivorous animal, and one which would be
quite able to, and probably did, kill animals as large as or larger than
itself.”
This opinion as to the carnivorous habits of _Thylacoleo_ is approved by
Mr. B. A. Bensley, who has specially studied the Australian marsupials
in a memoir recently published in the _Transactions_ of the Linnean
Society of London.
If it be correct, it reduces the net result of Flower’s investigations on
this subject to a fuller realisation of the diprotodont affinities of the
animal under consideration.
In the latter part of 1868, Mr. Flower, as he was then styled,
communicated to the Zoological Society a most important paper entitled,
“On the Value of the Characters of the Base of the Cranium in the
Classification of the Order Carnivora,” which was published in the first
part of the Society’s _Proceedings_ for the following year. Working
on the lines suggested twenty years previously by Mr. H. N. Turner,
who had pointed out the importance of certain peculiarities of the
base of the skull in the Mammalia, and especially demonstrated their
constancy in the different groups of the Carnivora, Flower felt himself
justified in dividing, on these characters, the existing terrestrial
representatives of that order into three groups. These were—1st, the
Æluroidea, comprising the cats (_Felidæ_), the fossa (_Cryptoproctidæ_),
civets and mongooses (_Viverridæ_), the aard-wolf (_Proteleidæ_), and
hyænas (_Hyænidæ_); 2nd, the Cynoidea, including only the dogs, wolves,
and foxes; and 3rd, the Arctoidea, embracing the bears (_Ursidæ_), the
raccoons and pandas (_Procyonidæ_ and _Æluridæ_), and the weasels,
badgers, otters, etc. (_Mustelidæ_).
One result of this classification from cranial characteristics was to
determine definitely the position of the American cacomistle (_Bassaris_
or _Bassariscus_), which had been previously uncertain. The genus, as
might have been expected from distributional considerations, turned out
to belong to the raccoon family (_Procyonidæ_).
As regards the relationship of the three main groups, subsequent
palæontological discoveries have fully confirmed Flower’s view that
the _Canidæ_ (Cynoidea) occupy a central, or perhaps rather a basal,
position. Palæontology has, however, also shown that the bears (_Ursidæ_)
are a direct offshoot from the _Canidæ_, and accordingly that, if
extinct forms be taken into consideration, there is no justification
for the separation of the two families into distinct primary groups
(Arctoidea and Cynoidea). On the other hand, fossil forms from the
Lower Tertiaries of France and of North America seem to demonstrate the
existence of a complete gradation between the primitive dogs (_Canidæ_)
and the ancestral civets (_Viverridæ_), thus breaking up the distinction
between the Cynoidea and the Æluroidea. Nor is this all, for according
to the French palæontologists, there exists a transition between the
primitive civets and the early weasels (_Mustelidæ_); which, with what
has been already stated in connection with the bears, indicates that
the Arctoidea is a more or less artificial group, the members of which
have come to resemble one another to a certain degree in regard to the
characters of the base of the skull, owing to “parallelism.” In this
connection it is somewhat curious to note that a certain resemblance,
which had been pointed out by Turner as existing between the mongooses
or ichneumons (_Viverridæ_) and the weasels, was regarded by Flower as
of no importance. Finally, it is by no means improbable that the cats
(_Felidæ_) have no near kinship with the civets, but may be directly
sprung from more primitive Carnivora.
It is thus evident that Flower’s proposed triple division of the
Carnivora is not altogether in accord with palæontological, or
phylogenetic, evidence. An amendment is to merge the Cynoidea in the
Arctoidea, and thus retain only two groups. The observations recorded in
the paper have a high permanent value, in respect to the structure of the
carnivorous skull.
Another paper by Flower appeared in the Zoological Society’s
_Proceedings_ for 1869, dealing with the anatomy of the soft parts of
that remarkable animal, the African aard-wolf (_Proteles cristatus_).
Although the skeleton had been previously described, no information
had hitherto been available with regard to the viscera. In the paper
discussed in the foregoing paragraphs Flower, from the external
characters, coupled with those of the dentition and skeleton, had
regarded the creature as the representative of a distinct family,
intermediate in some respects between the _Hyænidæ_ and the _Viverridæ_.
The result of the examination of the viscera was in the main to support
this conclusion, although it showed that the _Proteleidæ_ are more
closely allied to the _Hyænidæ_ than the author had previously believed
to be the case. The aard-wolf may, indeed, be regarded as a kind of
small and degraded hyæna, with an almost rudimentary type of dentition,
suitable to the soft substances on which it feeds.
Passing on to the year 1870, we have to note the appearance of two
separate works bearing Flower’s name. The first of these was the
_Introductory Lectures to the Course of Comparative Anatomy_, delivered
at the Royal College of Surgeons in that year. Far more important
was the issue of the first edition of that invaluable text-book, _An
Introduction to the Osteology of the Mammalia_. Since, however, mention
of this work had been already made in an earlier chapter, it need not be
further alluded to in this place.
During the same year, exclusive of those on the Cetacea, several papers
were published by Flower in various scientific serials. Among these, bare
mention must suffice for one, “On the Connexion of the Hyoid Arch with
the Cranium,” which appeared in the twentieth volume of the _Report_
of the British Association. More important is the article “On the
Correspondence between the parts composing the Shoulder and the Pelvic
Girdle of the Mammalia.” In this the author pointed out that although
the homology between the scapula in the shoulder-girdle and the ilium in
the pelvis had long been admitted by naturalists, yet much misconception
existed with regard to the exact correspondence between the respective
surfaces and borders of these bones; and he then proceeded to define
and describe these correspondences in considerable detail. The names
then assigned by Flower to the component surfaces and borders of the
bones in question have ever since been generally adapted by naturalists.
Observations were also recorded with regard to the homology between the
coracoid bone and the ischium. A second paper in the same journal for
1870 dealt with the carpus of the dog; while in 1873 he published in this
medium a note on the same part of the skeleton in the sloths.
Reverting once more to the _Proceedings_ of the Zoological Society,
in which the bulk of his contributions to the anatomy of mammals was
published, we find a paper by Flower in the volume for 1870 on the
anatomy of the Himalayan panda (_Ælurus fulgens_.)
The specimen on which the paper was based was the first example of
this remarkable animal which had ever been dissected; and the brain
and viscera were described at considerable length. The result of the
dissection was to confirm the author’s previous opinion—based on the
external characters and skeleton—as to the near affinity of _Ælurus_ to
the American _Procyonidæ_; and it was left somewhat an open question,
whether it should be included in that group, or regarded as the
representative of a family (_Æluridæ_) by itself. In after years Mr. W.
T. Blanford adopted the former view. In the following year (1871) Flower
contributed a note to the _Proceedings_, recording the occurrence of a
specimen of the ringed seal (_Phoca hispida_) on the Norfolk coast in
1846; and he also wrote a paper in the same volume on the skeleton of one
of the cassowaries. The somewhat remarkable fact that the two-spotted
palm-civet (_Nandinia binotata_) differs from the other genera of
the same group by the absence of a blind appendage, or cæcum, to the
intestine, was recorded by Flower in the same serial for 1872.
Of much more importance than either of the foregoing were two
contributions to mammalian anatomy made by Sir William during the year
last mentioned. The one, which appeared in the _Medical Times and
Gazette_, was the report of “Lectures on the Comparative Anatomy of the
Organs of Digestion in the Mammalia, delivered at the Royal College of
Surgeons in February and March, 1872.” In this article, which is well
illustrated, will be found descriptions of the various forms assumed by
the stomach in a large number of the ordinal and family groups; especial
attention being directed to the remarkable complexity of that organ in
the porpoise. The other, which was published in _Nature_, and in abstract
in the _Report_ of the British Association, dealt with the arrangement
and nomenclature of the lobes of the mammalian liver. It is, perhaps, one
of the most valuable of the author’s contributions to visceral anatomy;
and introduced order and precision where confusion had previously
reigned. The names then given to the different lobes of the liver have
been very generally adopted in zoological and anatomical literature.
In 1873 Flower delivered before the Royal Institution a lecture on
palæontological evidence of gradual modification of animal forms, which
is published in the _Proceedings_ of that body for the same year. In this
he touched on the important evidence afforded by the discoveries which
had then been recently made in North America in favour of the derivation
of one animal form from another, directing particular attention to the
case for the evolution of the horse. Another paper on the same subject
appears in the _British Medical Journal_ for 1874; while, as noticed
below, Sir William again lectured on palæontological evolution in 1876.
The year 1874 was noteworthy, so far as palæontology is concerned, by the
appearance in the _Philosophical Transactions_ of the Royal Society of a
paper by Flower on part of a remarkable mammalian skull from Patagonia,
described under the name of _Homalodontotherium cunninghami_. In justice
to the author, it should be said that he was not responsible for the
undue length of the generic name, which had been bestowed by his friend
Huxley four years previously in the Geological Society’s _Journal_, and
which Flower was therefore compelled to employ. It refers to the fact
that the jaws of the new animal are remarkable for the even and unbroken
wall formed by the teeth, which show no enlarged tusks. At the time the
geological age of this interesting fossil was quite unknown; but it
formed the forerunner of the marvellous discoveries of the remains of
fossil mammals of middle tertiary age in Patagonia, which have been made
of late years, and have done so much to increase our knowledge of the
past life and history of the South American Continent.
Of minor interest is a paper by the then Hunterian Professor in the
_Quarterly Journal_ of the Geological Society on a much rolled and
battered skull from the so-called Red Crag of Suffolk, which the author
referred to a species of that extinct genus of sea-cows (Sirenia) known
as _Halitherium_. Such interest as the specimen possessed was due to
its affording the first evidence of the occurrence of remains of that
genus in Britain. Another paper, it may be mentioned, was published by
Flower in the same journal for 1877, in which another well-known extinct
continental genus of mammals was added to the fauna of the Red Crag of
East Anglia. The paper described two molar teeth, in the York Museum,
from the deposit in question, evidently referable to the large bear-like
animal known as _Hyænarctus_, of which the first remains had been
described many years previously from the Siwalik Hills of North-Eastern
India. As the mention of this paper has broken the chronological order of
treatment, it may be added that in 1876 Flower published another paper,
this time in the Zoological Society’s _Proceedings_, on a mammalian skull
from the Red Crag. The specimen referred to in this communication was
provisionally assigned to Cuvier’s genus _Xiphodon_, and was believed to
have been originally washed out from a formation much older than the Red
Crag, and reburied in the latter.
Next on our list comes a paper on the anatomy of the musk-deer (_Moschus
moschiferus_), contributed to the serial last cited for 1875, in which
the author points out how widely this animal differs from the more
typical deer, and shows that it cannot even claim a near relationship
with the Chinese water-deer, despite the fact that in both species the
males are devoid of antlers, and are armed with long sabre-like tusks in
the upper jaw. In several respects—notably the presence of a gall-bladder
to the liver—the musk-deer is indeed nearer to the hollow-horned
ruminants (Bovidæ), than to the other members of the deer tribe (Cervidæ).
In 1876 Professor Flower delivered before the Royal Institution an
extremely interesting lecture on the extinct mammals of North America,
which at that time were in course of being made known to the scientific
world by the writings of Professors Marsh and Cope. In the course of
this lecture Flower alluded at considerable length to the ancestry
of the horse—then a comparatively new subject—and also discussed the
structure and affinities of those gigantic many-horned mammals commonly
known as Dinocerata. In concluding, the lecturer observed that the work
accomplished in America taught us—“First, that the living world around
us at the present moment bears but an exceedingly small proportion to
the whole series of animal and vegetable forms which have existed in past
ages. Secondly, that, notwithstanding all that has been said, and most
justly said, of the necessary imperfection of the geological record, we
may hope that there is still so much preserved that the study of the
course of events which have led up to the present condition of life on
the globe, may have a great future before it.”
The subsequent discoveries of fossil mammalian remains in such enormous
quantities in Patagonia, and still later in the Libyan desert, have
rendered this utterance almost prophetic.
During the same year (1876) appeared, in the _Philosophical
Transactions_, a notice by Flower of the seals and cetaceans obtained
during the _Transit of Venus_ expeditions of 1874 and 1875. The year
1876 likewise witnessed the publication, in the _Proceedings_ of the
Zoological Society, of an article on the skulls of the various existing
species of rhinoceroses, in which it was shown that the number of such
species had been altogether unjustifiably exaggerated by the late
Dr. J. E. Gray and other writers, and that in all probability there
were really not more than five. Certain characters connected with the
postero-lateral region of the skull were also described, which served to
divide these species into groups. A further contribution to our knowledge
of the skulls of the rhinoceroses was made by Flower in 1878, when he
described, in the same journal, the skull of an Indian specimen, which
it was thought might be the _Rhinoceros lasiotis_ of Dr. Sclater—now
known to be (as then suggested) merely a local race of the two-horned _R.
sumatrensis_.
Between the years 1880 and 1883 several papers on mammalian zoology were
published by Flower in the _Proceedings_ of the Zoological Society and
elsewhere, none of which can be regarded as of first-rate importance. The
first of these (_P.Z.S._ 1880) dealt with the internal anatomy of that
rare mammal, the bush-dog (_Speothus_, or _Icticyon_, _venaticus_), of
Guiana, which had never previously been described. The author regarded
this animal as a specialised member of the Canidæ, showing some signs
of affinity with the wild dogs (_Cyon_) of Asia. In 1880 the museum
of the Royal College of Surgeons received a very large skull of the
elephant-seal or sea-elephant (_Macrorhinus leoninus_); and this induced
Flower to draw up some notes on that enormous creature, which appeared
in the above-named journal for 1881. The author described it as “an
animal which, notwithstanding its former abundance and wide distribution,
and its great zoological interest, is still very imperfectly known
anatomically, and very poorly represented in collections.” Fortunately,
since that date—mainly owing to the energy and liberality of Mr.
Rothschild—specimens of the skin and skeleton of this huge seal have
been secured for our museums before it was too late. In the same volume
Flower drew attention to the evidence showing that the sea-cow, or
manati, of which a pair were living at the time in the Brighton Aquarium,
occasionally, or periodically, comes ashore for the purpose of grazing.
In the same year appeared an article from his pen in the _British Medical
Journal_ on the anatomy of the Cetacea and Edentata; while in 1882 the
question of the mutual relationships of the mammals commonly included in
the latter order (such as sloths, ant-eaters, armadillos, pangolins, and
aard-varks) were discussed by him in the _Proceedings_ of the Zoological
Society.
The trend of the paper last mentioned, as well as that of some of his
other communications published shortly before, indicates that about this
time, instead of restricting his attention more or less entirely to their
anatomy, Flower was much occupied with the subject of the classification
of the Mammalia. And the reason is not far to seek, for he had undertaken
not only the volume of the “Catalogue of Osteological Specimens in the
Museum of the Royal College of Surgeons,” dealing with mammals other
than man, but he had likewise engaged (in co-operation with the late Dr.
Dobson) to write the article “Mammalia” for the ninth edition of the
_Encyclopædia Britannica_. With the view apparently of clearing the way
for these two important contributions to zoology, he published during the
early part of 1883 in the Zoological Society’s _Proceedings_ a paper on
the “Arrangement of the Orders and Families of Mammalia.”
To discuss this important paper in detail on the present occasion is
quite unnecessary; and it will suffice to state that it has formed the
basis on which all modern classifications of the group are framed. Indeed
it has been accepted by most writers with little or no modification. In
this scheme it was proposed to divide mammals into three primary groups,
or sub-classes, namely, Prototheria, or Ornithodelphia, as represented
only by the egg-laying group; Metatheria or Didelphia, including the
pouched group, or marsupials; and Eutheria or Monodelphia, comprising the
whole of the remaining or placental groups. Of late years, owing to the
discovery of unexpected relationships between placentals and marsupials,
it has been proposed to recognise only two sub-classes of mammals: the
Eutheria, comprising the two groups last mentioned, and the Prototheria,
or monotremes. The scheme chiefly differed from the one proposed some
years earlier by Huxley in the inclusion of the Hyracoidea (klipdass) and
Proboscidea (elephants) as sub-orders of the Ungulata, instead of their
forming separate orders by themselves. In this instance Flower ranked the
Artiodactyla, Perissodactyla, Hyracoidea, and Proboscidea as equivalent
sub-orders of Ungulata, but later on he brigaded the two former together
as Ungulata Vera, and the two latter as Subungulata.
The above scheme was employed by Flower in the article “Mammalia,”
written by him for the ninth edition of the _Encyclopædia Britannica_,
the volume containing which appeared in 1883. This article, with others
by himself and other authors, formed, as will be noticed later on,
the basis of the _Study of Mammals_ published in 1891. Among other
articles contributed by Flower to the _Encyclopædia_ were those on the
Horse, Kangaroo, Lemur, Lion, Mastodon, Megatherium, Otter, Platypus,
Rhinoceros, Seal, Swine, Tapir, Whale, and Zebra.
The aforesaid scheme of classification was likewise used in the second
part of the “Catalogue of Osteological Specimens in the Museum of the
Royal College of Surgeons,” which was written with the assistance of Dr.
Garson, and appeared in 1884. Since this valuable work has been already
noticed at some length in the chapter devoted to Flower’s official
connection with the College of Surgeons, it need not be further referred
to in this place, except that the writer may again take the opportunity
of expressing his regret that the views on nomenclature there enunciated
have not met with acceptance among the modern school of naturalists.
At the “Jubilee” meeting of the Zoological Society, held in June 1887,
Flower, as President, read an address on the “Progress of Zoological
Science” during the reign of Queen Victoria, which appeared in the
_Report_ of the Council of that year, and to which reference has been
made in an earlier chapter.
About this time the Natural History Museum received a series of antlers
shed year by year by one particular red-deer stag, together with the
complete skull and antlers of the same animal; and this gift induced
Flower to deliver in December 1887 a lecture on “Horns and Antlers”
before the Middlesex Natural History Society, which is printed, with
a plate of the aforesaid series of red-deer antlers, in a somewhat
abbreviated form, in the _Transactions_ of that Society.
If we except a few on Cetacea, noticed in the next chapter, Sir William’s
contributions to the Zoological Society’s _Proceedings_ after 1883 were
not numerous or of much importance. In 1884 he contributed, however,
remarks on the so-called white elephant from Burma, then exhibited in
the Society’s Menagerie; and in the same year he also wrote on the young
dentition of the capybara. In 1887 he discussed the generic position
and relationships of the pigmy hippopotamus of Liberia. The acquisition
in the following year by the Natural History Museum of specimens of
that breed of Japanese fowls remarkable for the excessive elongation
of the tail-feathers of the cocks, led to a note on that subject in
the _Proceedings_ for the same year. This paper, it may be incidentally
mentioned, is noteworthy, on account of the evidence it affords that Sir
William did not regard the variations displayed by domesticated animals
as in any way unworthy the notice of the naturalist; while the next shows
that monstrosities or abnormalities—at all events to a certain extent—are
also worthy of recognition. The note incidentally alluded to in the
last sentence appeared in 1889, and dealt with an African rhinoceros
head, showing three horns. Finally, in 1890, Sir William exhibited and
commented upon a photograph of the nesting-hole of a hornbill, showing
the female “walled up” with mud.
The next year (1891) saw the publication of _An Introduction to the
Study of Mammals, Living and Extinct_, written, as already said, in
collaboration with the present writer, and embodying the whole of
Flower’s contributions to the _Encyclopædia Britannica_, together with
certain articles by other authors from the same work, and such new
material as was necessary in order to weave these _disjecta membra_ into
one connected and harmonious whole.
In the same year was also published, in the _Modern Science Series_, Sir
William’s admirable little volume on _The Horse_, which was likewise
largely based on his _Encyclopædia_ articles. In this work Flower dwelt
particularly on the vestiges exhibited by the modern horse of its descent
from more generalised ancestors; and he was successful in demonstrating
that the structure known to veterinarians as the “ergot,” represents one
of the foot-pads of the earlier forms.
Undoubtedly the most important elements in the foregoing tale of work are
those relating to the mammalian (and especially the marsupial) brain, and
the marsupial dentition. And if Flower had accomplished nothing more than
this, he would have been entitled to gratitude of his successors. But,
as we shall immediately see, all the above formed but a portion of his
zoological labours.