India than to _M. sancti-johannis_ of South China.
2. _Pteropus formosus._ A fruit-bat closely allied to the Japanese
species. None of the genus are found in China.
3. Vesperugo abramus. China.
4. Vespertilio formosus. Black and orange Bat. China.
5. Nyctinomus cestonii. Large-eared Bat. China, S. Europe.
6. _Talpa insularis._ A blind mole of a peculiar species.
{403} 7. Sorex murinus. Musk Rat. China.
8. Sorex sp. A shrew, undescribed.
9. Erinaceus sp. A Hedgehog, undescribed.
10. Ursus tibetanus. The Tibetan Bear. Himalayas and North China.
11. _Helictis subaurantiaca._ The orange-tinted Tree Civet. Allied to
_H. nipalensis_ of the Himalayas more than to _H. moschata_ of
China.
12. Martes flavigula, var. The yellow-necked Marten. India, China.
13. Felis macroscelis. The clouded Tiger of Siam and Malaya.
14. Felis viverrina. The Asiatic wild Cat. Himalayas and Malacca.
15. Felis chinensis. The Chinese Tiger Cat. China.
16. Viverricula malaccensis. Spotted Civet. China, India.
17. Paguma larvata. Gem-faced Civet. China.
18. _Sus taivanus._ Allied to the wild Pig of Japan.
19. Cervulus reevesii. Reeve's Muntjac. China.
20. _Cervus pseudaxis._ Formosan Spotted Deer. Allied to _C. sika_ of
Japan.
21. _Cervus swinhoii._ Swinhoe's Rusa Deer. Allied to Indian and
Malayan species.
22. _Nemorhedus swinhoii._ Swinhoe's Goat-antelope. Allied to the
species of Sumatra and Japan.
23. Bos chinensis. South China wild Cow.
24. Mus bandicota. The Bandicoot Rat. Perhaps introduced from India.
25. Mus indicus. Indian Rat.
26. _Mus coxinga._ Spinous Country-rat.
27. _Mus canna._ Silken Country-rat.
28. _Mus losca_. Brown Country-rat.
29. Sciurus castaneoventris. Chestnut-bellied Squirrel. China and
Hainan.
30. Sciurus m'clellandi. McClelland's Squirrel. Himalayas, China.
31. _Sciuropterus kaleensis._ Small Formosan Flying Squirrel. Allied to
_S. alboniger_ of Nepal.
32. _Pteromys grandis._ Large Red Flying Squirrel. Allied to Himalayan
and Bornean species. From North Formosa.
33. _Pteromys pectoralis._ White-breasted Flying Squirrel. From South
Formosa.
34. Lepus sinensis. Chinese Hare. Inhabits South China.
35. Manis dalmanni. Scaly Ant-eater. China and the Himalayas.
The most interesting and suggestive feature connected with these Formosan
mammals is the identity or affinity of several of them, with Indian or
Malayan rather than with Chinese species. We have the rock-monkey of
Formosa allied to the rhesus monkeys of India and Burma, not to those of
South China and Hainan. The tree civet (_Helictis subaurantiaca_), and the
small flying squirrel (_Sciuropterus kaleensis_), are both allied to
Himalayan species. Swinhoe's deer and goat-antelope are nearest to Malayan
species, as are the red and white-breasted flying squirrels; while the
fruit-bat, the wild pig, {404} and the spotted deer are all allied to
peculiar Japanese species. The clouded tiger is a Malay species unknown in
China, while the Asiatic wild cat is a native of the Himalayas and Malacca.
It is clear, therefore, that before Formosa was separated from the mainland
the above named animals or their ancestral types must have ranged over the
intervening country as far as the Himalayas on the west, Japan on the
north, and Borneo or the Philippines on the south; and that after that
event occurred, the conditions were so materially changed as to lead to the
extinction of these species in what are now the coast provinces of China,
while they or their modified descendants continued to exist in the dense
forests of the Himalayas and the Malay Islands, and in such detached
islands as Formosa and Japan. We will now see what additional light is
thrown upon this subject by an examination of the birds.
LIST OF THE LAND BIRDS PECULIAR TO FORMOSA.
TURDIDAE (Thrushes).
1. _Turdus albiceps._ Allied to Chinese species.
SYLVIDIAE (Warblers).
2. _Cisticola volitans._ Allied to _C. schoenicola_ of India and
China.
3. _Herbivox cantans._ Sub-species of _H. cantillaus_ of N. China and
Japan.
4. _Notodela montium._ Allied to _N. leucura_ of the Himalayas; no ally
in China.
TIMALIIDAE (Babblers).
5. _Pomatorhinus musicus._ Allies in S. China and the Himalayas.
6. _P. erythroenemis._ Do. do.
7. _Garrulax ruficeps._ Allied to _G. albogularis_ of N. India and East
Thibet, not to the species of S. China (_G. sannio_).
8. _Janthocincla poecilorhyncha._ Allied to _J. coerulata_ of the
Himalayas. None of the genus in China.
9. _Trochalopteron taivanus._ Allied to a Chinese species.
10. _Alcippe morrisoniana._} Near the Himalayan _A. nipalensis_.
11. _A. brunnea._ } None of the genus in China.
12. _Sibia auricularis._ Allied to the Himalayan _S. capistrata_. The
genus not known in China.
PANURIDAE (Bearded Tits, &c.).
13. _Suthora bulomachus._ Allied to the Chinese _S. suffusa_.
CINCLIDAE (Dippers and Whistling Thrushes).
14. _Myiophoneus insularis._ Allied to _M. horsfieldi_ of South India.
{405}
PARIDAE (Tits).
15. _Parus insperatus._ Sub-species of _P. monticola_ of the Himalayas
and East Thibet.
16. _P. castaneiventris._ Allied to _P. varius_ of Japan.
LIOTRICHIDAE (Hill Tits).
17. _Liocichla steerii._ A peculiar genus of a specially Himalayan
family, quite unknown in China.
PYCNONOTIDAE (Bulbuls).
18. _Pycnonotus (Spizixos) cinereicapillus_. Very near _P. semitorques_
of China.
19. _Hypsipetes nigerrimus._ Allied to _H. concolor_ of Assam, not to
_H. macclellandi_ of China.
ORIOLIDAE (Orioles).
20. _Analcipus ardens._ Allied to _A. traillii_ of the Himalayas and
Tenasserim.
CAMPEPHAGIDAE (Caterpillar Shrikes).
21. _Graucalus rex-pineti._ Closely allied to the Indian _G. macei_. No
ally in China.
DICRURIDAE (King Crows).
22. _Chaptia brauniana._ Closely allied to _C. aenea_ of Assam. No ally
in China.
MUSCICAPIDAE (Flycatchers).
23. _Cyornis vivida._ Allied to _C. rubeculoides_ of India.
CORVIDAE (Jays and Crows).
24. _Garrulus taivanus._ Allied to _G. sinensis_ of S. China.
25. _Urocissa coerulea._ A very distinct species from its Indian and
Chinese allies.
26. _Dendrocitta formosae._ A sub-species of the Chinese _D. sinensis_.
PLOCEIDAE (Weaver Finches).
27. _Munia formosana._ Allied to _M. rubronigra_ of India and Burmah.
ALAUDIDAE (Larks).
28. _Alauda sala._}Allies in South China.
29. _A. wattersi._}
PITTIDAE (Pittas).
30. _Pitta oreas._ Allied to _P. cyanoptera_ of Malaya and S. China.
PICIDAE (Woodpeckers).
31. _Picus insularis._ Allied to _P. leuconotus_ of Japan and Siberia.
MEGALAEMIDAE.
32. _Megalaema nuchalis._ Allied to _M. oortii_ of Sumatra and _M.
faber_ of Hainan. No allies in China.
CAPRIMULGIDAE (Goatsuckers).
33. _Caprimulgus stictomus._ A sub-species of _C. monticolus_ of India
and China.
{406}
COLUMBIDAE (Pigeons).
34. _Treron formosae._ Allied to Malayan species.
35. _Sphenocercus sororius._ Allied to Malay species and to _S.
sieboldi_ of Japan. No allies of these two birds inhabit China.
36. _Chalcophaps formosana._ Allied to the Indian species which extends
to Tenasserim and Hainan.
TETRAONIDAE (Grouse and Partridges).
37. _Orcoperdix crudigularis._ A peculiar genus of partridges.
38. _Bambusicola sonorivox._ Allied to the Chinese _B. thoracica_.
39. _Arcoturnix rostrata._ Allied to the Chinese _A. blakistonii_.
PHASIANIDAE (Pheasants).
40. _Phasianus formosanus._ Allied to _P. torquatus_ of China.
41. _Euplocamus swinhoii._ A very peculiar and beautiful species allied
to the tropical fire-backed pheasants, and to the silver pheasant of
North China.
STRIGIDAE (Owls).
42. _Athene pardalota._ Closely allied to a Chinese species.
43. _Lempigius hambroekii._ Allied to a Chinese species.
This list exhibits to us the marvellous fact that more than half the
peculiar species of Formosan birds have their nearest allies in such remote
regions as the Himalayas, South India, the Malay Islands, or Japan, rather
than in the adjacent parts of the Asiatic continent. Fourteen species have
Himalayan allies, and six of these belong to genera which are unknown in
China. One has its nearest ally in the Nilgherries, and five in the Malay
Islands; and of these six, four belong to genera which are not Chinese. Two
have their only near allies in Japan. Perhaps more curious still are those
cases in which, though the genus is Chinese, the nearest allied species is
to be sought for in some remote region. Thus we have the Formosan babbler
(_Garrulax ruficeps_) not allied to the species found in South China, but
to one inhabiting North India and East Thibet; while the black bulbul
(_Hypsipetes nigerrimus_), is not allied to the Chinese species but to an
Assamese form.
In the same category as the above we must place eight species not peculiar
to Formosa, but which are Indian or Malayan rather than Chinese, so that
they offer examples of discontinuous distribution somewhat analogous to
what {407} we found to occur in Japan. These are enumerated in the
following list.
SPECIES OF BIRDS COMMON TO FORMOSA AND INDIA OR MALAYA, BUT NOT FOUND IN
CHINA.
1. _Siphia superciliaris._ The Rufous-breasted Flycatcher of the S. E.
Himalayas.
2. _Halcyon coromanda._ The Great Red Kingfisher of India, Malaya, and
Japan.
3. _Palumbus pulchricollis._ The Darjeeling Wood-pigeon of the S. E.
Himalayas.
4. _Turnix dussumieri._ The larger Button-quail of India.
5. _Spizaetus nipalensis._ The Spotted Hawk-eagle of Nepal and Assam.
6. _Lophospiza trivirgata._ The Crested Gos-hawk of the Malay Islands.
7. _Bulaca newarensis._ The Brown Wood-owl of the Himalayas.
8. _Strix candida._ The Grass-owl of India and Malaya.
The most interesting of the above are the pigeon and the flycatcher, both
of which are, so far as yet known, strictly confined to the Himalayan
mountains and Formosa. They thus afford examples of discontinuous specific
distribution exactly parallel to that of the great spotted kingfisher,
already referred to as found only in the Himalayas and Japan.
_Comparison of the Faunas of Hainan, Formosa, and Japan._--The island of
Hainan on the extreme south of China, and only separated from the mainland
by a strait fifteen miles wide, appears to have considerable similarity to
Formosa, inasmuch as it possesses seventeen peculiar land-birds (out of 130
obtained by Mr. Swinhoe), two of which are close allies of Formosan
species, while two others are identical. We also find four species whose
nearest allies are in the Himalayas. Our knowledge of this island and of
the adjacent coast of China is not yet sufficient to enable us to form an
accurate judgment of its relations, but it seems probable that it was
separated from the continent at, approximately, the same epoch as Formosa
and Japan, and that the special features of each of these islands are
mainly due to their geographical position. Formosa, being more completely
isolated than either of the others, possesses a larger proportion of
peculiar species of birds, while its tropical situation and lofty mountain
ranges {408} have enabled it to preserve an unusual number of Himalayan and
Malayan forms. Japan, almost equally isolated towards the south, and having
a much greater variety of climate as well as a much larger area, possesses
about an equal number of mammalia with Formosa, and an even larger
proportion of peculiar species. Its birds, however, though more numerous
are less peculiar; and this is probably due to the large number of species
which migrate northwards in summer, and find it easy to enter Japan through
the Kurile Isles or Saghalien.[96] Japan too, is largely peopled by those
northern types which have an unusually wide range, and which, being almost
all migratory, are accustomed to cross over seas of moderate extent. The
regular or occasional influx of these species prevents the formation of
special insular races, such as are almost always produced when a portion of
the population of a species remains for a considerable time completely
isolated. We thus have explained the curious fact, that while the mammalia
of the two islands are almost equally peculiar, (those of Japan being most
so in the present state of our knowledge), the birds of Formosa show a far
greater number of peculiar species than those of Japan.
_General Remarks on Recent Continental Islands._--We have now briefly
sketched the zoological peculiarities of an illustrative series of recent
continental islands, commencing with one of the most recent--Great
Britain--in which the process of formation of peculiar species has only
just commenced, and terminating with Formosa, probably one of the most
ancient of the series, and which accordingly presents us with a very large
proportion of peculiar species, not only in its mammalia, which have no
means of crossing the wide strait which separates it from the mainland, but
also in its birds, many of which are quite able to cross over.
Here, too, we obtain a glimpse of the way in which {409} species die out
and are replaced by others, which quite agrees with what the theory of
evolution assures us must have occurred. On a continent, the process of
extinction will generally take effect on the circumference of the area of
distribution, because it is there that the species comes into contact with
such adverse conditions or competing forms as prevent it from advancing
further. A very slight change will evidently turn the scale and cause the
species to contract its range, and this usually goes on till it is reduced
to a very restricted area, and finally becomes extinct. It may conceivably
happen (and almost certainly has sometimes happened) that the process of
restriction of range by adverse conditions may act in one direction only,
and over a limited district, so as ultimately to divide the specific area
into two separated parts, in each of which a portion of the species will
continue to maintain itself. We have seen that there is reason to believe
that this has occurred in a very few cases both in North America and in
Northern Asia. (_See_ pp. 65-68.) But the same thing has certainly occurred
in a considerable number of cases, only it has resulted in the divided
areas being occupied by _representative forms_ instead of by the very same
species. The cause of this is very easy to understand. We have already
shown that there is a large amount of local variation in a considerable
number of species, and we may be sure that were it not for the constant
intermingling and intercrossing of the individuals inhabiting adjacent
localities this tendency to local variation in adaptation to slightly
different conditions, would soon form distinct races. But as soon as the
area is divided into two portions the intercrossing is stopped, and the
usual result is that two closely allied races, classed as representative
species, become formed. Such pairs of allied species on the two sides of a
continent, or in two detached areas, are very numerous; and their existence
is only explicable on the supposition that they are descendants of a parent
form which once occupied an area comprising that of both of them,--that
this area then became discontinuous,--and, lastly, that, as a consequence
of the discontinuity, the two sections of the parent species became
segregated into distinct races or new species. {410}
Now, when the division of the area leaves one portion of the species in an
island, a similar modification of the species, either in the island or in
the continent, occurs, resulting in closely-allied but distinct forms; and
such forms are, as we have seen, highly characteristic of island-faunas.
But islands also favour the occasional preservation of the unchanged
species--a phenomenon which very rarely occurs in continents. This is
probably due to the absence of competition in islands, so that the parent
species there maintains itself unchanged, while the continental portion, by
the force of that competition, is driven back to some remote mountain area,
where it also obtains a comparative freedom from competition. Thus may be
explained the curious fact, that the species common to Formosa and India
are generally confined to limited areas in the Himalayas, or in other cases
are found only in remote islands, as Japan or Hainan.
The distribution and affinities of the animals of continental islands thus
throws much light on that obscure subject--the decay and extinction of
species; while the numerous and delicate gradations in the modification of
the continental species, from perfect identity, through slight varieties,
local forms, and insular races, to well-defined species and even distinct
genera, afford an overwhelming mass of evidence in favour of the theory of
"descent with modification."
We shall now pass on to another class of islands, which, though originally
forming parts of continents, were separated from them at very remote
epochs. This antiquity is clearly manifested in their existing faunas,
which present many peculiarities, and offer some most curious problems to
the student of distribution.
* * * * *
{411}
CHAPTER XIX
ANCIENT CONTINENTAL ISLANDS: THE MADAGASCAR GROUP
Remarks on Ancient Continental Islands--Physical Features of
Madagascar--Biological Features of
Madagascar--Mammalia--Reptiles--Relation of Madagascar to Africa--Early
History of Africa and Madagascar--Anomalies of Distribution and How to
Explain Them--The Birds of Madagascar as Indicating a Supposed Lemurian
Continent--Submerged Islands between Madagascar and India--Concluding
Remarks on "Lemuria"--The Mascarene Islands--The Comoro Islands--The
Seychelles Archipelago--Birds of the Seychelles--Reptiles and
Amphibia--Freshwater Fishes--Land Shells--Mauritius, Bourbon, and
Rodriguez--Birds--Extinct Birds and their Probable
Origin--Reptiles--Flora of Madagascar and the Mascarene
Islands--Curious Relations of Mascarene Plants--Endemic Genera of
Mauritius and Seychelles--Fragmentary Character of the Mascarene
Flora--Flora of Madagascar Allied to that of South
Africa--Preponderance of Ferns in the Mascarene Flora--Concluding
Remarks on the Madagascar Group.
We have now to consider the phenomena presented by a very distinct class of
islands--those which, although once forming part of a continent, have been
separated from it at a remote epoch when its animal forms were very unlike
what they are now. Such islands preserve to us the record of a by-gone
world,--of a period when many of the higher types had not yet come into
existence and when the distribution of others was very different from what
prevails at the present day. The problem presented by these ancient islands
is often complicated by the changes they themselves have undergone since
the period of their separation. A partial subsidence will have led to the
{412} extinction of some of the types that were originally preserved, and
may leave the ancient fauna in a very fragmentary state; while subsequent
elevations may have brought it so near to the continent that some
immigration even of mammalia may have taken place. If these elevations and
subsidences occurred several times over, though never to such an extent as
again to unite the island with the continent, it is evident that a very
complex result might be produced; for besides the relics of the ancient
fauna, we might have successive immigrations from surrounding lands
reaching down to the era of existing species. Bearing in mind these
possible changes, we shall generally be able to arrive at a fair
conjectural solution of the phenomena of distribution presented by these
ancient islands.
Undoubtedly the most interesting of such islands, and that which exhibits
their chief peculiarities in the greatest perfection, is Madagascar, and we
shall therefore enter somewhat fully into its biological and physical
history.
_Physical Features of Madagascar._--This great island is situated about 250
miles from the east coast of Africa, and extends from 12deg to 25-1/2deg S.
Lat. It is almost exactly 1,000 miles long, with an extreme width of 360
and an average width of more than 260 miles. A lofty granitic plateau, from
eighty to 160 miles wide and from 3,000 to 5,000 feet high, occupies its
central portion, on which rise peaks and domes of basalt and granite to a
height of nearly 9,000 feet; and there are also numerous extinct volcanic
cones and craters. All round the island, but especially developed on the
south and west, are plains of a few hundred feet elevation, formed of rocks
which are shown by their fossils to be of Jurassic age, or at all events to
belong to somewhere near the middle portion of the Secondary period. The
higher granitic plateau consists of bare undulating moors, while the lower
Secondary plains are more or less wooded; and there is here also a
continuous belt of dense forest, varying from six or eight to fifty miles
wide, encircling the whole island, usually at about thirty miles distance
from the coast but in the north-east coming down to the sea-shore. {413}
[Illustration]
{414}
The sea around Madagascar, when the shallow bank on which it stands is
passed, is generally deep. This 100-fathom bank is only from one to three
miles wide on the east side, but on the west it is much broader, and
stretches out opposite Mozambique to a distance of about eighty miles. The
Mozambique Channel is rather more than 1,000 fathoms deep, but there is
only a narrow belt of this depth opposite Mozambique, and still narrower
where the Comoro Islands and adjacent shoals seem to form stepping-stones
to the continent of Africa. The 1,000-fathom line includes Aldabra and the
small Farquhar Islands to the north of Madagascar; while to the east the
sea deepens rapidly to the 1,000-fathom line and then more slowly, a
profound channel of 2,400 fathoms separating Madagascar from Bourbon and
Mauritius. To the north-east of Mauritius are a series of extensive shoals
forming four large banks less than 100 fathoms below the surface, while the
1,000-fathom line includes them all, with an area about half that of
Madagascar itself. A little further north is the Seychelles group, also
standing on an extensive 1,000-fathom bank, while all round the sea is more
than 2,000 fathoms deep.
It seems probable, then, that to the north-east of Madagascar there was
once a series of very large islands, separated from it by not very wide
straits; while eastward across the Indian Ocean we find the Chagos and
Maldive coral atolls, perhaps marking the position of other large islands,
which together would form a line of communication, by comparatively easy
stages of 400 or 500 miles each between Madagascar and India. These
submerged islands, as shown in our map at p. 424, are of great importance
in explaining some anomalous features in the zoology of this great island.
If the rocks of Secondary age which form a belt around the island are held
to indicate that Madagascar was once of less extent than it is now (though
this by no means necessarily follows), we have also evidence that it has
recently been considerably larger; for along the east coast there is an
extensive barrier coral-reef about 350 miles in length, and varying in
distance from the land from a quarter of a mile to three or four miles.
This seems to indicate recent subsidence; while we have no record of raised
coral rocks inland which would certainly mark any recent elevation, though
fringing coral reefs surround a considerable portion of the northern,
eastern, and south-western coasts. We may therefore conclude that during
Tertiary times the island was usually as large as, and often probably much
larger than, it is now. {415}
[Illustration: MAP OF THE MADAGASCAR GROUP, SHOWING DEPTHS OF SEA.]
In this Map the depth of the sea is shown by three tints; the lightest tint
indicating from 0 to 100 fathoms, the medium tint from 100 to 1,000
fathoms, the dark tint more than 1,000 fathoms.
{416}
_Biological Features of Madagascar._--Madagascar possesses an exceedingly
rich and beautiful fauna and flora, rivalling in some groups most tropical
countries of equal extent, and even when poor in species, of surpassing
interest from the singularity, the isolation, or the beauty of its forms of
life. In order to exhibit the full peculiarity of its natural history and
the nature of the problems it offers to the biological student, we must
give an outline of its more important animal forms in systematic order.
_Mammalia._--Madagascar possesses no less than sixty-six species of
mammals--a certain proof in itself that the island has once formed part of
a continent; but the character of these animals is very extraordinary and
altogether different from the assemblage now found in Africa or in any
other existing continent. Africa is now most prominently characterised by
its monkeys, apes, and baboons; by its lions, leopards, and hyaenas; by its
zebras, rhinoceroses, elephants, buffaloes, giraffes, and numerous species
of antelopes. But no one of these animals, nor any thing like them, is
found in Madagascar, and thus our first impression would be that it could
never have been united with the African continent. But, as the tigers, the
bears, the tapirs, the deer, and the numerous squirrels of Asia are equally
absent, there seems no probability of its having been united with that
continent. Let us then see to what groups the mammalia of Madagascar
belong, and where we must look for their probable allies.
First and most important are the lemurs, consisting of six genera and
thirty-three species, thus comprising just half the entire mammalian
population of the island. This group of lowly-organised and very ancient
creatures {417} still exists scattered over a wide area; but they are
nowhere so abundant as in the island of Madagascar. They are found from
West Africa to India, Ceylon, and the Malay Archipelago, consisting of a
number of isolated genera and species, which appear to maintain their
existence by their nocturnal and arboreal habits, and by haunting dense
forests. It can hardly be said that the African forms of lemurs are more
nearly allied to those of Madagascar than are the Asiatic, the whole series
appearing to be the disconnected fragments of a once more compact and
extensive group of animals.
Next, we have about a dozen species of Insectivora, consisting of one
shrew, a group distributed over all the great continents; and five genera
of a peculiar family, Centetidae, which family exists nowhere else on the
globe except in the two largest West Indian Islands, Cuba and Hayti, thus
adding still further to our embarrassment in seeking for the original home
of the Madagascar fauna.
We then come to the Carnivora, which are represented by a peculiar cat-like
animal, Cryptoprocta, forming a distinct family, and having no close allies
in any part of the globe; and eight civets belonging to four peculiar
genera. Here we first meet with some decided indications of an African
origin; for the civet family is more abundant in this continent than in
Asia, and some of the Madagascar genera seem to be decidedly allied to
African groups--as, for example, Eupleres to Suricata and Crossarchus.[97]
The Rodents consist only of four rats and mice of peculiar genera, one of
which is said to be allied to an American genus; and lastly we have a
river-hog of the African genus Potamochaerus, and a small sub-fossil
hippopotamus, both of which being semi-aquatic animals might easily have
reached the island from Africa, by way of the Comoros, without any actual
land connection.[98]
_Reptiles of Madagascar._--Passing over the birds for the present, as not
so clearly demonstrating {418} land-connection, let us see what indications
are afforded by the reptiles. The large and universally distributed family
of Colubrine snakes is represented in Madagascar, not by African or Asiatic
genera, but by two American genera--Philodryas and Heterodon, and by
Herpetodryas, a genus found in America and China. The other genera are all
peculiar, and belong mostly to widespread tropical families; but two
families--Lycodontidae and Viperidae, both abundant in Africa and the
Eastern tropics--are absent. Lizards are mostly represented by peculiar
genera of African or tropical families, but several African genera are
represented by peculiar species, and there are also some species belonging
to two American genera of the Iguanidae, a family which is exclusively
American; while a genus of geckoes, inhabiting America and Australia, also
occurs in Madagascar.
_Relation of Madagascar to Africa._--These facts taken all together are
certainly very extraordinary, since they show in a considerable number of
cases as much affinity with America as with Africa; while the most striking
and characteristic groups of animals now inhabiting Africa are entirely
wanting in Madagascar. Let us first deal with this fact, of the absence of
so many of the most dominant African groups. The explanation of this
deficiency is by no means difficult, for the rich deposits of fossil
mammals of Miocene or Pliocene age in France, Germany, Greece, and
North-west India, have demonstrated the fact that all the great African
mammals then inhabited Europe and temperate Asia. We also know that a
little earlier (in Eocene times) tropical Africa was cut off from Europe
and Asia by a sea stretching from the Atlantic to the Bay of Bengal, at
which time Africa must have formed a detached island-continent such as
Australia is now, and probably, like it, very poor in the higher forms of
life. Coupling these two facts, the inference seems clear, that all the
higher types of mammalia were developed in the great Euro-Asiatic continent
(which then included Northern Africa), and that they only migrated into
tropical Africa when the two continents became united by the upheaval of
the sea-bottom, probably {419} in the latter portion of the Miocene or
early in the Pliocene period.[99]
It is clear, therefore, that if Madagascar had once formed part of Africa,
but had been separated from it before Africa was united to Europe and Asia,
it would not contain any of those kinds of animals which then first entered
the country. But, besides the African mammals, we know that some birds now
confined to Africa then inhabited Europe, and we may therefore fairly
assume that all the more important groups of birds, reptiles, and insects,
now abundant in Africa but absent from Madagascar, formed no part of the
original African fauna, but entered the country only after it was joined to
Europe and Asia.
_Early History of Africa and Madagascar._--We have seen that Madagascar
contains an abundance of mammals, and that most of them are of types either
peculiar to, or existing also in, Africa; it follows that that continent
must have had an earlier union with Europe, Asia, or America, or it could
never have obtained any mammals at all.
{420} Now these ancient African mammals are Lemurs, Insectivora, and small
Carnivora, chiefly Viverridae; and all these groups are known to have
inhabited Europe in Eocene and Miocene times; and that the union was with
Europe rather than with America is clearly proved by the fact that even the
insectivorous Centetidae, now confined to Madagascar and the West Indies,
inhabited France in the Lower Miocene period, while the Viverridae, or
civets, which form so important a part of the fauna of Madagascar as well
as of Africa, were abundant in Europe throughout the whole Tertiary period,
but are not known to have ever lived in any part of the American continent.
We here see the application of the principle which we have already fully
proved and illustrated (Chapter IV., p. 60), that all extensive groups have
a wide range at the period of their maximum development; but as they decay
their area of distribution diminishes or breaks up into detached fragments,
which one after another disappear till the group becomes extinct. Those
animal forms which we now find isolated in Madagascar and other remote
portions of the globe all belong to ancient groups which are in a decaying
or nearly extinct condition, while those which are absent from it belong to
more recent and more highly-developed types, which range over extensive and
continuous areas, but have had no opportunity of reaching the more ancient
continental islands.
_Anomalies of Distribution and How to Explain Them._--If these
considerations have any weight, it follows that there is no reason whatever
for supposing any former direct connection between Madagascar and the
Greater Antilles merely because the insectivorous Centetidae now exist only
in these two groups of islands; for we know that the ancestors of this
family must once have had a much wider range, which almost certainly
extended over the great northern continents. We might as reasonably suppose
a land-connection across the Pacific to account for the camels of Asia
having their nearest existing allies in the llamas and alpacas of the
Peruvian Andes, and another between Sumatra and Brazil, in order that the
ancestral tapir of one country might have passed over to the other. In both
{421} these cases we have ample proof of the former wide extension of the
group. Extinct camels of numerous species abounded in North America in
Miocene, Pliocene, and even Post-pliocene times, and one has also been
found in North-western India, but none whatever among all the rich deposits
of mammalia in Europe. We are thus told, as clearly as possible, that from
the North American continent as a centre the camel tribe spread westward,
over now-submerged land at the shallow Behring Straits and Kamschatka Sea,
into Asia, and southward along the Andes into South America. Tapirs are
even more interesting and instructive. Their remotest known ancestors
appear in Western Europe in the early portion of the Eocene period; in the
latter Eocene and the Miocene other forms occur both in Europe and North
America. These seem to have become extinct in North America, while in
Europe they developed largely into many forms of true tapirs, which at a
much later period found their way again to North, and thence to South,
America, where their remains are found in caves and gravel deposits. It is
an instructive fact that in the Eastern continent, where they were once so
abundant, they have dwindled down to a single species, existing in small
numbers in the Malay Peninsula, Sumatra, and Borneo only; while in the
Western continent, where they are comparatively recent immigrants, they
occupy a much larger area, and are represented by three or four distinct
species. Who could possibly have imagined such migrations, and extinctions,
and changes of distribution as are demonstrated in the case of the tapirs,
if we had only the distribution of the existing species to found an opinion
upon? Such cases as these--and there are many others equally striking--show
us with the greatest distinctness how nature has worked in bringing about
the examples of anomalous distribution that everywhere meet us; and we
must, on every ground of philosophy and common sense, apply the same method
of interpretation to the more numerous instances of anomalous distribution
we discover among such groups as reptiles, birds, and insects, where we
rarely have any direct evidence of their past migrations through the
discovery of {422} fossil remains. Whenever we can trace the past history
of any group of terrestrial animals, we invariably find that its actual
distribution can be explained by migrations effected by means of
comparatively slight modifications of our existing continents. In no single
case have we any direct evidence that the distribution of land and sea has
been radically changed during the whole lapse of the Tertiary and Secondary
periods, while, as we have already shown in our fifth chapter, the
testimony of geology itself, if fairly interpreted, upholds the same theory
of the stability of our continents and the permanence of our oceans. Yet so
easy and pleasant is it to speculate on former changes of land and sea with
which to cut the gordian knot offered by anomalies of distribution, that we
still continually meet with suggestions of former continents stretching in
every direction across the deepest oceans, in order to explain the presence
in remote parts of the globe of the same genera even of plants or of
insects--organisms which possess such exceptional facilities both for
terrestrial, aerial, and oceanic transport, and of whose distribution in
early geological periods we generally know little or nothing.
_The Birds of Madagascar, as Indicating a Supposed Lemurian
Continent._--Having thus shown how the distribution of the land mammalia
and reptiles of Madagascar may be well explained by the supposition of a
union with Africa before the greater part of its existing fauna had reached
it, we have now to consider whether, as some ornithologists think, the
distribution and affinities of the birds present an insuperable objection
to this view, and require the adoption of a hypothetical
continent--Lemuria--extending from Madagascar to Ceylon and the Malay
Islands.
There are about one hundred and fifty land birds known from the island of
Madagascar, of which a hundred and twenty-seven are peculiar; and about
half of these peculiar species belong to peculiar genera, many of which are
extremely isolated, so that it is often difficult to class them in any of
the recognised families, or to determine their affinities to any living
birds.[100] Among the other moiety, {423} belonging to known genera, we
find fifteen which have undoubted African affinities, while five or six are
as decidedly Oriental, the genera or nearest allied species being found in
India or the Malay Islands. It is on the presence of these peculiar Indian
types that Dr. Hartlaub, in his recent work on the _Birds of Madagascar and
the Adjacent Islands_, lays great stress, as proving the former existence
of "Lemuria"; while he considers the absence of such peculiar African
families as the plantain-eaters, glossy-starlings, ox-peckers, barbets,
honey-guides, hornbills, and bustards--besides a host of peculiar African
genera--as sufficiently disproving the statement in my _Geographical
Distribution of Animals_ that Madagascar is "more nearly related to the
Ethiopian than to any other region," and that its fauna was evidently
"mainly derived from Africa."
But the absence of the numerous peculiar groups of African birds is so
exactly parallel to the same phenomenon among mammals, that we are
justified in imputing it to the same cause, the more especially as some of
the very groups that are wanting--the plantain-eaters and the trogons, for
example,--are actually known to have inhabited Europe along with the large
mammalia which subsequently migrated to Africa. As to the peculiarly
Eastern genera--such as Copsychus and Hypsipetes, with a Dicrurus, a
Ploceus, a Cisticola, and a Scops, all closely allied to Indian or Malayan
species--although very striking to the ornithologist, they certainly do not
outweigh the fourteen African genera found in Madagascar. Their presence
may, moreover, be accounted for more satisfactorily than by means of an
ancient Lemurian continent, which, even if granted, would not explain the
very facts adduced in its support.
Let us first prove this latter statement.
The supposed "Lemuria" must have existed, if at all, at so remote a period
that the higher animals did not then inhabit either Africa or Southern
Asia, and it must have {424} become partially or wholly submerged before
they reached those countries; otherwise we should find in Madagascar many
other animals besides Lemurs, Insectivora, and Viverridae, especially such
active arboreal creatures as monkeys and squirrels, such hardy grazers as
deer or antelopes, or such wide-ranging carnivores as foxes or bears. This
obliges us to date the disappearance of the hypothetical continent about
the earlier part of the Miocene epoch at latest, for during the latter part
of that period we know that such animals existed in abundance in every part
of the great northern continents wherever we have found organic remains.
But the Oriental birds in Madagascar, by whose presence Dr. Hartlaub
upholds the theory of a Lemuria, are slightly modified forms of _existing
Indian genera_, or sometimes, as Dr. Hartlaub himself points out, _species
hardly distinguishable from those of India_. Now all the evidence at our
command leads us to conclude that, even if these genera and species were in
existence in the early Miocene period, they must have had a widely
different distribution from what they have now. Along with so many African
and Indian genera of mammals they then probably inhabited Europe, which at
that epoch enjoyed a sub-tropical climate; and this is rendered almost
certain by the discovery in the Miocene of France of fossil remains of
trogons and jungle-fowl. If, then, these Indian birds date back to the very
period during which alone Lemuria could have existed, that continent was
quite unnecessary for their introduction into Madagascar, as they could
have followed the same track as the mammalia of Miocene Europe and Asia;
while if, as I maintain, they are of more recent date, then Lemuria had
ceased to exist, and could not have been the means of their introduction.
_Submerged Islands between Madagascar and India._--Looking at the
accompanying map of the Indian Ocean, we see that between Madagascar and
India there are now extensive shoals and coral reefs, such as are usually
held to indicate subsidence; and we may therefore fairly postulate the
former existence here of several large islands, some of them not much
inferior to Madagascar itself. These reefs are all separated from each
other by very deep {425} sea--much deeper than that which divides
Madagascar from Africa, and we have therefore no reason to imagine their
former union. But they would nevertheless greatly facilitate the
introduction of Indian birds into the Mascarene Islands and Madagascar; and
these facilities existing, such an immigration would be sure to take place,
just as surely as American birds have entered the Galapagos and Juan
Fernandez, as European birds now reach the Azores, and as Australian birds
reach such a distant island as New Zealand. This would take place the more
certainly because the Indian Ocean is a region of violent periodical storms
at the changes of the monsoons, and we have seen in the case of the Azores
and Bermuda how important a factor this is in determining the transport of
birds across the ocean.
[Illustration: MAP OF THE INDIAN OCEAN.
Showing the position of banks less than 1,000 fathoms deep between Africa
and the Indian Peninsula.]
{426}
The final disappearance of these now sunken islands does not, in all
probability, date back to a very remote epoch; and this exactly accords
with the fact that some of the birds, as well as the fruit-bats of the
genus Pteropus, are very closely allied to Indian species, if not actually
identical, others being distinct species of the same genera. The fact that
not one closely-allied species or even genus of Indian or Malayan mammals
is found in Madagascar, sufficiently proves that it is no land-connection
that has brought about this small infusion of Indian birds and bats; while
we have sufficiently shown, that, when we go back to remote geological
times no land-connection in this direction was necessary to explain the
phenomena of the distribution of the Lemurs and Insectivora. A
land-connection with _some_ continent was undoubtedly necessary, or there
would have been no mammalia at all in Madagascar; and the nature of its
fauna on the whole, no less than the moderate depth of the intervening
strait and the comparative approximation of the opposite shores, clearly
indicate that the connection was with Africa.
_Concluding Remarks on "Lemuria."_--I have gone into this question in some
detail, because Dr. Hartlaub's criticism on my views has been reproduced in
a scientific periodical,[101] and the supposed Lemurian continent is
constantly referred to by quasi-scientific writers, as well as by
naturalists and geologists, as if its existence had been demonstrated by
facts, or as if it were absolutely necessary to postulate such a land in
order to account for the entire series of phenomena connected with the
Madagascar fauna, and especially with the distribution of the
Lemuridae.[102] I {427} think I have now shown, on the other hand, that it
was essentially a provisional hypothesis, very useful in calling attention
to a remarkable series of problems in geographical distribution, but not
affording the true solution of those problems, any more than the hypothesis
of an Atlantis solved the problems presented by the Atlantic Islands and
the relations of the European and North American flora and fauna. The
Atlantis is now rarely introduced seriously except by the absolutely
unscientific, having received its death-blow by the chapter on Oceanic
Islands in the _Origin of Species_, and the researches of Professor Asa
Gray on the affinities of the North American and Asiatic floras. But
"Lemuria" still keeps its place--a good example of the survival of a
provisional hypothesis which offers what seems an easy solution of a
difficult problem, and has received an appropriate and easily remembered
name, long after it has been proved to be untenable.
It is now more than fifteen years since I first showed, by a careful
examination of all the facts to be accounted for, that the hypothesis of a
Lemurian continent was alike unnecessary to explain one portion of the
facts, and inadequate to explain the remaining portion.[103] Since that
time I have seen no attempt even to discuss the question on general grounds
in opposition to my views, nor on the other hand have those who have
hitherto supported the hypothesis taken any opportunity of acknowledging
its weakness and inutility. I have therefore here explained my reasons for
rejecting it somewhat more fully and in a more popular form, in the hope
that a check may thus be placed on the continued re-statement of this
unsound theory as if it were one of the accepted conclusions of modern
science.
{428}
_The Mascarene Islands._[104]--In the _Geographical Distribution of
Animals_, a summary is given of all that was known of the zoology of the
various islands near Madagascar, which to some extent partake of its
peculiarities, and with it form the Malagasy sub-region of the Ethiopian
region. As no great additions have since been made to our knowledge of the
fauna of these islands, and my object in this volume being more especially
to illustrate the mode of solving distributional problems by means of the
most suitable examples, I shall now confine myself to pointing out how far
the facts presented by these outlying islands support the views already
enunciated with regard to the origin of the Madagascar fauna.
_The Comoro Islands._--This group of islands is situated nearly midway
between the northern extremity of Madagascar and the coast of Africa. The
four chief islands vary between sixteen and forty miles in length, the
largest being 180 miles from the coast of Africa, while one or two smaller
islets are less than 100 miles from Madagascar. All are volcanic, Great
Comoro being an active volcano 8,500 feet high; and, as already stated,
they are situated on a submarine bank with less than 500 fathoms soundings,
connecting Madagascar with Africa. There is reason to believe, however,
that these islands are of comparatively recent origin, and that the bank
has been formed by matter ejected by the volcanoes or by upheaval. Anyhow,
there is no indication whatever of there having been here a land-connection
between Madagascar and Africa; while the islands themselves have been
mainly colonised from Madagascar, some of them making a near approach to
the 100-fathom bank which surrounds that island.
The Comoros contain two land mammals, a lemur and a civet, both of
Madagascar genera and the latter an identical species, and there is also a
peculiar species of fruit-bat (_Pteropus comorensis_), a group which ranges
from Australia to Asia and Madagascar but is unknown in Africa. Of
land-birds forty-one species are known, of {429} which sixteen are peculiar
to the islands, twenty-one are found also in Madagascar, and three found in
Africa and not in Madagascar; while of the peculiar species, six belong to
Madagascar or Mascarene genera. A species of Chameleon is also peculiar to
the islands.
These facts point to the conclusion that the Comoro Islands have been
formerly more nearly connected with Madagascar than they are now, probably
by means of intervening islets and the former extension of the latter
island to the westward, as indicated by the extensive shallow bank at its
northern extremity, so as to allow of the easy passage of birds, and the
occasional transmission of small mammalia by means of floating trees.[105]
_The Seychelles Archipelago._--This interesting group consists of about
thirty small islands situated 700 miles N.N.E. of Madagascar, or almost
exactly in the line formed by continuing the central ridge of that great
island. The Seychelles stand upon a rather extensive shallow bank, the
100-fathom line around them enclosing an area nearly 200 miles long by 100
miles wide, while the 500-fathom line shows an extension of nearly 100
miles in a southern direction. All the larger islands are of granite, with
mountains rising to 3,000 feet in Mahe, and to from 1,000 to 2,000 feet in
several of the other islands. We can therefore hardly doubt that they form
a portion of the great line of upheaval which produced the central granitic
mass of Madagascar, intervening points being indicated by the Amirantes,
the Providence, and the Farquhar Islands, which, though all coralline,
probably rest on a granitic basis. Deep channels of more than 1,000 fathoms
now separate these islands from each other, and if they were ever
sufficiently elevated to be united, it was probably at a very remote epoch.
The Seychelles may thus have had ample facilities for receiving from
Madagascar such immigrants as can pass over narrow seas; and, on the other
hand, they were equally favourably situated as regards the extensive Saya
de Malha and Cargados banks, which were probably once {430} large islands,
and may have supported a rich insular flora and fauna of mixed Mascarene
and Indian type. The existing fauna and flora of the Seychelles must
therefore be looked upon as the remnants which have survived the partial
submergence of a very extensive island; and the entire absence of
non-aerial mammalia may be due, either to this island having never been
actually united to Madagascar, or to its having since undergone so much
submergence as to have led to the extinction of such mammals as may once
have inhabited it. The birds and reptiles, however, though few in number,
are very interesting, and throw some further light on the past history of
the Seychelles.
_Birds of the Seychelles._--Fifteen indigenous land-birds are known to
inhabit the group, thirteen of which are peculiar species,[106] belonging
to genera which occur also in Madagascar or Africa. The genera which are
more peculiarly Indian are,--Copsychus and Hypsipetes, also found in
Madagascar; and Palaeornis, which has species in Mauritius and Rodriguez,
as well as one on the continent of Africa. A black parrot (Coracopsis),
congeneric with two species that inhabit Madagascar and with one that is
peculiar to the Comoros; and a beautiful red-headed blue pigeon
(_Alectoraenas pulcherrimus_) allied to those of Madagascar and Mauritius,
but very distinct, are the most remarkable species characteristic of this
group of islands.
_Reptiles and Amphibia of the Seychelles._--The reptiles and amphibia are
rather numerous and very interesting, indicating clearly that the islands
can hardly be classed as oceanic. There are seven species of lizards, three
being peculiar to the islands, while the others have rather a wide range.
The first is a chameleon--defenceless {431} slow-moving lizards, especially
abundant in Madagascar, from which no less than eighteen species are now
known, about the same number as on the continent of Africa. The Seychelles
species (_Chamaeleon tigris_) also occurs at Zanzibar. The next are skinks
(Scincidae), small ground-lizards with a wide distribution in the Eastern
hemisphere. Two species are however peculiar to the islands--_Mabuia
seychellensis_ and _M. wrightii_. The other peculiar species is one of the
geckoes (Geckotidae) named _Aeluronyx seychellensis_, and there are also
three other geckoes, _Phelsuma madagascarensis_, _Gehyra mutilata_ and
_Hemidactylus frenatus_, the two latter having a wide distribution in the
tropical regions of both hemispheres. These lizards, clinging as they do to
trees and timber, are exceedingly liable to be carried in ships from one
country to another, and I am told by Dr. Guenther that some are found
almost every year in the London Docks. It is therefore probable, that when
species of this family have a very wide range they have been assisted in
their migrations by man, though their habit of clinging to trees also
renders them likely to be floated with large pieces of timber to
considerable distances. Dr. Percival Wright, to whom I am indebted for much
information on the productions of the Seychelles Archipelago, informs me
that the last-named species varies greatly in colour in the different
islands, so that he could always tell from which particular island a
specimen had been brought. This is analogous to the curious fact of certain
lizards on the small islands in the Mediterranean being always very
different in colour from those of the mainland, usually becoming rich blue
or black (see _Nature_, Vol. XIX. p. 97); and we thus learn how readily in
some cases differences of colour are brought about, either directly or
indirectly, by local conditions.
Snakes, as is usually the case in small or remote islands, are far less
numerous than lizards, only two species being known. One, _Dromicus
seychellensis_, is a peculiar species of the family Colubridae, the rest of
the genus being found in Madagascar and South America. The other, _Boodon
geometricus_, one of the Lycodontidae, or fanged ground-snakes, is also
peculiar. So far, then, as the reptiles are {432} concerned, there is
nothing but what is easily explicable by what we know of the general means
of distribution of these animals.
We now come to the Amphibia, which are represented in the Seychelles by two
tailless and two serpent-like forms. The frogs are _Rana mascareniensis_,
found also in Mauritius, Bourbon, Angola, and Abyssinia, and probably all
over tropical Africa; and _Megalixalus seychellensis_ a peculiar tree-frog
having allies in Madagascar and tropical Africa. It is found, Dr. Wright
informs me, on the Pandani or screw-pines; and as these form a very
characteristic portion of the vegetation of the Mascarene Islands, all the
species being peculiar and confined each to a single island or small group,
we may perhaps consider it as a relic of the indigenous fauna of that more
extensive land of which the present islands are the remains.
The serpentine Amphibia are represented by two species of Caecilia. These
creatures externally resemble large worms, except that they have a true
head with jaws and rudimentary eyes, while internally they have of course a
true vertebrate skeleton. They live underground, burrowing by means of the
ring-like folds of the skin which simulate the jointed segments of a worm's
body, and when caught they exude a viscid slime. The young have external
gills which are afterwards replaced by true lungs, and this peculiar
metamorphosis shows that they belong to the amphibia rather than to the
reptiles. The Caecilias are widely but very sparingly distributed through
all the tropical regions; a fact which may, as we have seen, be taken as an
indication of the great antiquity of the group, and that it is now verging
towards extinction. In the Seychelles Islands there appear to be three
species of these singular animals. _Cryptopsophis multiplicatus_ is
confined to the islands; _Herpele squalostoma_ is found also in Western
India and in Africa; while _Hypogeophis rostratus_ inhabits both West
Africa and South America.[107] This last is certainly one of the most
remarkable cases of the wide and discontinuous distribution of a species;
and {433} when we consider the habits of life of these animals and the
extreme slowness with which it is likely they can migrate into new areas,
we can hardly arrive at any other conclusion than that this species once
had an almost world-wide range, and that in the process of dying out it has
been left stranded, as it were, in these three remote portions of the
globe. The extreme stability and long persistence of specific form which
this implies is extraordinary, but not unprecedented, among the lower
vertebrates. The crocodiles of the Eocene period differ but slightly from
those of the present day, while a small freshwater turtle from the Pliocene
deposits of the Siwalik Hills is absolutely identical with a still living
Indian species, _Emys tectus_. The mud-fish of Australia, _Ceratodus
forsteri_ is a very ancient type, and may well have remained specifically
unchanged since early Tertiary times. It is not, therefore, incredible that
this Seychelles Caecilia may be the oldest land vertebrate now living on
the globe; dating back to the early part of the Tertiary period, when the
warm climate of the northern hemisphere in high latitudes and the union of
the Asiatic and American continents allowed of the migration of such types
over the whole northern hemisphere, from which they subsequently passed
into the southern hemisphere, maintaining themselves only in certain
limited areas, where the physical conditions were especially favourable, or
where they were saved from the attacks of enemies or the competition of
higher forms.
_Fresh-water Fishes._--The only other vertebrates in the Seychelles are two
fresh-water fishes abounding in the streams and rivulets. One, _Haplochilus
playfairii_ is peculiar to the islands, but there are allied species in
Madagascar. It is a pretty little fish about four inches long, of an olive
colour, with rows of red spots, and is very abundant in some of the
mountain streams. The fishes of this genus, as I am informed by Dr.
Guenther, often inhabit both sea and fresh water, so that their migration
from {434} Madagascar to the Seychelles and subsequent modification, offers
no difficulty. The other species is _Fundulus orthonotus_, found also on
the east coast of Africa; and as both belong to the same
family--Cyprinodontidae--this may possibly have migrated in a similar
manner.
_Land-shells._--The only other group of animals inhabiting the Seychelles
which we know with any approach to completeness, are the land and
fresh-water mollusca, but they do not furnish any facts of special
interest. About forty species are known, and Mr. Geoffrey Nevill, who has
studied them, thinks their meagre number is chiefly owing to the
destruction of so much of the forests which once covered the islands. Seven
of the species--and among them one of the most conspicuous, _Achatina
fulica_--have almost certainly been introduced; and the remainder show a
mixture of Madagascar and Indian forms, with a preponderance of the latter.
Five genera--Streptaxis, Cyathoponea, Onchidium, Helicina and Paludomus,
are mentioned as being especially Indian, while only two--Tropidophora and
Gibbus, are found in Madagascar but not in India.[108] About two-thirds of
the species appear to be peculiar to the islands.
_Mauritius, Bourbon and Rodriguez._--These three islands are somewhat out
of place in this chapter, because they really belong to the oceanic group,
being of volcanic formation, surrounded by deep sea, and possessing no
indigenous mammals or amphibia. Yet their productions are so closely
related to those of Madagascar, to which they may be considered as
attendant satellites, that it is absolutely necessary to associate them
together if we wish to comprehend and explain their many interesting
features.
Mauritius and Bourbon are lofty volcanic islands, evidently of great
antiquity. They are about 100 miles apart, and the sea between them is less
than 1,000 fathoms deep, while on each side it sinks rapidly to depths of
2,400 and 2,600 fathoms. We have therefore no reason to believe that they
have ever been connected with {435} Madagascar, and this view is strongly
supported by the character of their indigenous fauna. Of this, however, we
have not a very complete or accurate knowledge, for though both islands
have long been occupied by Europeans, the study of their natural products
was for a long time greatly neglected, and owing to the rapid spread of
sugar cultivation, the virgin forests, and with them no doubt many native
animals, have been almost wholly destroyed. There is, however, no good
evidence of there ever having been any indigenous mammals or amphibia,
though both are now found and are often recorded among the native
animals.[109]
The smaller and more remote island, Rodriguez, is also volcanic; but it
has, besides a good deal of coralline rock, an indication of partial
submergence helping to account for the poverty of its fauna and flora. It
stands on a 100-fathom bank of considerable extent, but beyond this the
{436} sea rapidly deepens to more than 2,000 fathoms, so that it is truly
oceanic like its larger sister isles.
_Birds._--The living birds of these islands are few in number and consist
mainly of peculiar species of Mascarene types, together with two peculiar
genera--Oxynotus belonging to the Campephagidae or caterpillar-catchers, a
family abundant in the old-world tropics; and a dove, Trocazza, forming a
peculiar sub-genus. The origin of these birds offers no difficulty, looking
at the position of the islands and of the surrounding shoals and islets.
_Extinct Birds._--These three islands are, however, preeminently remarkable
as having been the home of a group of large ground-birds, quite incapable
of flight, and altogether unlike anything found elsewhere on the globe; and
which, though once very abundant, have become totally extinct within the
last two hundred years. The best known of these birds is the dodo, which
inhabited Mauritius; while allied species certainly lived in Bourbon and
Rodriguez, abundant remains of the species of the latter island--the
"solitaire," having been discovered, corresponding with the figure and
description given of it by Legouat, who resided in Rodriguez in 1692. These
birds constitute a distinct family, Dididae, allied to the pigeons but very
isolated. They were quite defenceless, and were rapidly exterminated when
man introduced dogs, pigs, and cats into the island, and himself sought
them for food. The fact that such perfectly unprotected creatures survived
in great abundance to a quite recent period in these three islands only,
while there is no evidence of their ever having inhabited any other
countries whatever, is itself almost demonstrative that Mauritius, Bourbon,
and Rodriguez are very ancient but truly oceanic islands. From what we know
of the general similarity of Miocene birds to living genera and families,
it seems clear that the origin of so remarkable a type as the dodos must
date back to early Tertiary times. If we suppose some ancestral
ground-feeding pigeon of large size to have reached the group by means of
intervening islands afterwards submerged, and to have thenceforth remained
to increase and multiply unchecked by the attacks of any more {437}
powerful animals, we can well understand that the wings, being useless,
would in time become almost aborted.[110] It is also not improbable that
this process would be aided by natural selection, because the use of wings
might be absolutely prejudicial to the birds in their new home. Those that
flew up into trees to roost, or tried to cross over the mouths of rivers,
might be blown out to sea and destroyed, especially during the hurricanes
which have probably always more or less devastated the islands; while on
the other hand the more bulky and short-winged individuals, who took to
sleeping on the ground in the forest, would be preserved from such dangers,
and perhaps also from the attacks of birds of prey which may always have
visited the islands. But whether or no this was the mode by which these
singular birds acquired their actual form and structure, it is perfectly
certain that their existence and development depended on complete isolation
and on freedom from the attacks of enemies. We have no single example of
such defenceless birds having ever existed on a continent at any geological
period, whereas analogous though totally distinct forms do exist in New
Zealand, where enemies are equally wanting. On the other hand, every
continent has always produced abundance of carnivora adapted to prey upon
the herbivorous animals inhabiting it at the same period; and we may
therefore be sure that {438} these islands have never formed part of a
continent during any portion of the time when the dodos inhabited them.
It is a remarkable thing that an ornithologist of Dr. Hartlaub's
reputation, looking at the subject from a purely ornithological point of
view, should yet entirely ignore the evidence of these wonderful and unique
birds against his own theory, when he so confidently characterises Lemuria
as "that sunken land, which, containing parts of Africa, must have extended
far eastward over Southern India and Ceylon, and the highest points of
which we recognise in the volcanic peaks of Bourbon and Mauritius, and in
the central range of Madagascar itself--the last resorts of the mostly
extinct Lemurine race which formerly peopled it."[111] It is here implied
that lemurs formerly inhabited Bourbon and Mauritius, but of this there is
not a particle of evidence, and we feel pretty sure that had they done so
the dodos would never have been developed there. In Madagascar there are no
traces of dodos, while there are remains of extinct gigantic struthious
birds of the genus Aepyornis, which were no doubt as well able to protect
themselves against the smaller carnivora as are the ostriches, emus, and
cassowaries in their respective countries at the present day.
The whole of the evidence at our command, therefore, tends to establish in
a very complete manner the "oceanic" character of the three
islands--Mauritius, Bourbon, and Rodriguez, and that they have never formed
part of "Lemuria" or of any continent.
_Reptiles._--Mauritius, like Bourbon, has lizards, some of which are
peculiar species; but no snakes, and no frogs or toads but such as have
been introduced.[112] Strange to say, however, a small islet called Round
Island, only about a mile across, and situated about fourteen miles
north-east of Mauritius, possesses a snake which is not only unknown in
Mauritius, but also in any other part of the world, being {439} altogether
confined to this minute islet! It belongs to the boa family, and forms a
peculiar and very distinct genus, Casaria, whose nearest allies seem to be
the Ungalia of Cuba and Bolyeria of Australia. It is hardly possible to
believe that this serpent has very long maintained itself on so small an
island; and though we have no record of its existence on Mauritius, it may
very well have inhabited the lowland forests without being met with by the
early settlers; and the introduction of swine, which soon ran wild and
effected the final destruction of the dodo, may also have been fatal to
this snake. It is, however, now almost certainly confined to the one small
islet, and is probably the land-vertebrate of most restricted distribution
on the globe.
On the same island there is a small lizard, _Scelotes bojeri_, recorded
also from Mauritius and Bourbon, though it appears to be rare in both
islands; but a gecko, _Phelsuma guentheri_, is restricted to the island. As
Round Island is connected with Mauritius by a bank under a hundred fathoms
below the surface, it has probably been once joined to it, and when first
separated would have been both much larger and much nearer the main island,
circumstances which would greatly facilitate the transmission of these
reptiles to their present dwelling-place, where they have been able to
maintain themselves owing to the complete absence of competition, while
some of them have become extinct in the larger island.
_Flora of Madagascar and the Mascarene Islands._--The botany of the great
island of Madagascar has been perhaps more thoroughly explored than that of
the opposite coasts of Africa, so that its peculiarities may not be really
so great as they now appear to be. Yet there can be no doubt of its extreme
richness and grandeur, its remarkable speciality, and its anomalous
external relations. It is characterised by a great abundance of
forest-trees and shrubs of peculiar genera or species, and often adorned
with magnificent flowers. Some of these are allied to African forms, others
to those of Asia, and it is said that of the two affinities the latter
preponderates. But there are also, as in the animal world, some decided
South {440} American relations, while other groups point to Australia, or
are altogether isolated.
No less than 3,740 flowering plants are now known from Madagascar with 360
ferns and fern-allies. The most abundant natural orders are the following:
Species.
Leguminosae 346
Ferns 318
Compositae 281
Euphorbiaceae 228
Orchideae 170
Cyperaceae 160
Rubiaceae 147
Acanthaceae 131
Gramineae 130
The flora contains representatives of 144 natural orders and 970 genera,
one of the former and 148 of the latter being peculiar to the island. The
peculiar order, Chaelnaceae, comprises seven genera and twenty-four
species; while Rubiaceae and Compositae have the largest number of peculiar
genera, followed by Leguminosae and Melastomaceae. Nearly three-fourths of
the species are endemic.
Beautiful flowers are not conspicuous in the flora of Madagascar, though it
contains several magnificent flowering plants. A shrub with the dreadful
name _Harpagophytum Grandidieri_ has bunches of gorgeous red flowers;
_Tristellateia madagascariensis_ is a climbing plant with spikes of rich
yellow flowers; while _Poinciana regia_, a tall tree, _Rhodolaena altivola_
and _Astrapoea Wallichii_, shrubs, are among the most magnificent flowering
plants in the world. _Disa Buchenaviana_, _Commelina madagascarica_, and
_Tachiadenus platypterus_ are fine blue-flowered plants, while the superb
orchid _Angraecum sesquipedale_, _Vinca rosea_, _Euphorbia splendens_, and
_Stephanotis floribunda_, have been long cultivated in our hot-houses.
There are also many handsome Combretaceae, Rubiaceae, and Leguminosae; but,
as in most tropical regions, this wealth of floral beauty has to be
searched for, and produces little effect in the landscape.
The affinities of the Madagascar flora are to a great extent in accordance
with those of the fauna. The tropical portion of the flora agrees closely
with that of tropical Africa, while the plants of the highlands are {441}
equally allied to those of the Cape and of the mountains of Central Africa.
Some Asiatic types are present which do not occur in Africa; and even the
curious American affinities of some of the animals are reproduced in the
vegetable kingdom. These last are so interesting that they deserve to be
enumerated. An American genus of Euphorbiaceae, Omphalea, has one species
in Madagascar, and Pedilanthus, another genus of the same natural order,
has a similar distribution. Myrosma, an American genus of Scitamineae has
one Madagascar species; while the celebrated "travellers' tree," _Ravenala
madagascariensis_, belonging to the order Musaceae, has its nearest ally in
a plant inhabiting N. Brazil and Guiana. Echinolaena, a genus of grasses,
has the same distribution.[113]
Of the flora of the smaller Madagascarian islands we possess a fuller
account, owing to the recent publication of Mr. Baker's _Flora of the
Mauritius and the Seychelles_, including also Rodriguez. The total number
of species in this flora is 1,058, more than half of which (536) are
exclusively Mascarene--that is, found only in some of the islands of the
Madagascar group, while nearly a third (304) are endemic or confined to
single islands. Of the widespread plants sixty-six are found in Africa but
not in Asia, and eighty-six in Asia but not in Africa, showing a similar
Asiatic preponderance to what is said to occur in Madagascar. With the
genera, however, the proportions are different, for I find by going through
the whole of the generic distributions as given by Mr. Baker, that out of
the 440 genera of wild plants fifty are endemic, twenty-two are Asiatic but
not African, while twenty-eight are African but not Asiatic. This implies
that the more ancient connection has been on the side of Africa, while a
more recent immigration, shown by identity of species, has come from the
side of Asia; and it is already certain that when the flora of Madagascar
is more thoroughly worked out, a still greater African preponderance will
be found in that island.
{442}
A few Mascarene genera are found elsewhere only in South America,
Australia, or Polynesia; and there are also a considerable number of genera
whose metropolis is South America, but which are represented by one or more
species in Madagascar, and by a single often widely distributed species in
Africa. This fact throws light upon the problem offered by those mammals,
reptiles, and insects of Madagascar which now have their only allies in
South America, since the two cases would be exactly parallel were the
African plants to become extinct. Plants, however, are undoubtedly more
long-lived specifically than animals--especially the more highly organised
groups, and are less liable to complete extinction through the attacks of
enemies or through changes of climate or of physical geography; hence we
find comparatively few cases in which groups of Madagascar plants have
their _only_ allies in such distant regions as America and Australia, while
such cases are numerous among animals, owing to the extinction of the
allied forms in intervening areas, for which extinction, as we have already
shown, ample cause can be assigned.
_Curious Relations of Mascarene Plants._--Among the curious affinities of
Mascarene plants we have culled the following from Mr. Baker's volume.
Trochetia, a genus of Sterculiaceae, has four species in Mauritius, one in
Madagascar, and one in the remote island of St. Helena. Mathurina, a genus
of Turneraceae, consisting of a single species peculiar to Rodriguez, has
its nearest ally in another monotypic genus, Erblichia, confined to Central
America. Siegesbeckia, one of the Compositae, consists of two species, one
inhabiting the Mascarene islands, the other Peru. Labourdonasia, a genus of
Sapotaceae, has two species in Mauritius, one in Natal, and one in Cuba.
Nesogenes, belonging to the verbena family, has one species in Rodriguez
and one in Polynesia. Mespilodaphne, an extensive genus of Lauraceae, has
six species in the Mascarene islands, and all the rest (about fifty
species) in South America. Nepenthes, the well-known pitcher plants, are
found chiefly in the Malay Islands, South China, and Ceylon, with species
in the Seychelles Islands, {443} and in Madagascar. Milla, a large genus of
Liliaceae, is exclusively American, except one species found in Mauritius
and Bourbon. Agauria, a genus of Ericaceae, is found in Madagascar, the
Mascarene islands, the plateau of Central Africa, and the Camaroon
Mountains in West Africa. An acacia, found in Mauritius and Bourbon (_A.
heterophylla_), can hardly be separated specifically from _Acacia koa_ of
the Sandwich Islands. The genus Pandanus, or screw-pine, has sixteen
species in the three islands--Mauritius, Rodriguez, and the Seychelles--all
being peculiar, and none ranging beyond a single island. Of palms there are
fifteen species belonging to ten genera, and all these genera are peculiar
to the islands. We have here ample evidence that plants exhibit the same
anomalies of distribution in these islands as do the animals, though in a
smaller proportion; while they also exhibit some of the transitional stages
by which these anomalies have, in all probability, been brought about,
rendering quite unnecessary any other changes in the distribution of sea
and land than physical and geological evidence warrants.[114]
{444}
_Fragmentary Character of the Mascarene Flora._--Although the peculiar
character and affinities of the vegetation of these islands is sufficiently
apparent, there can be little doubt that we only possess a fragment of the
rich flora which once adorned them. The cultivation of sugar, and other
tropical products, has led to the clearing away of the virgin forests from
all the lowlands, plateaus, and accessible slopes of the mountains, so that
remains of the aboriginal woodlands only linger in the recesses of the
hills, and numbers of forest-haunting plants must inevitably have been
exterminated. The result is, that nearly three hundred species of foreign
plants have run wild in Mauritius, and have in their turn helped to
extinguish the native {445} species. In the Seychelles, too, the indigenous
flora has been almost entirely destroyed in most of the islands, although
the peculiar palms, from their longevity and comparative hardiness, have
survived. Mr. Geoffrey Nevill tells us, that at Mahe, and most of the other
islands visited by him, it was only in a few spots near the summits of the
hills that he could perceive any remains of the ancient flora. Pine-apples,
cinnamon, bamboos, and other plants have obtained a firm footing, covering
large tracts of country and killing the more delicate native flowers and
ferns. The pine-apple, especially, grows almost to the tops of the
mountains. Where the timber and shrubs have been destroyed, the water
falling on the surface immediately cuts channels, runs off rapidly, and
causes the land to become dry and arid; and the same effect is largely seen
both in Mauritius and Bourbon, where, originally, dense forest covered the
entire surface, and perennial moisture, with its ever-accompanying
luxuriance of vegetation, prevailed.
_Flora of Madagascar Allied to that of South Africa._--In my _Geographical
Distribution of Animals_ I have remarked on the relation between the
insects of Madagascar and those of south temperate Africa, and have
speculated on a great _southern_ extension of the continent at the time
when Madagascar was united with it. As supporting this view I now quote Mr.
Bentham's remarks on the Compositae. He says: "The connections of the
Mascarene endemic Compositae, especially those of Madagascar itself, are
eminently with the southern and sub-tropical African races; the more
tropical races, Plucheineae, &c., may be rather more of an Asiatic type."
He further says that the Composite flora is almost as strictly endemic as
that of the Sandwich Islands, and that it is much diversified, with
evidences of great antiquity, while it shows insular characteristics in the
tendency to tall shrubby or arborescent forms in several of the endemic or
prevailing genera.
_Preponderance of Ferns in the Mascarene Flora._--A striking character of
the flora of these smaller Mascarene islands is the great preponderance of
ferns, and next to them of orchideae. The following figures are taken from
{446} Mr. Baker's _Flora_ for Mauritius and the Seychelles, and from an
estimate by M. Frappier of the flora of Bourbon given in Maillard's volume
already quoted:--
_Mauritius, &c._ _Bourbon._
Ferns 168 Ferns 240
Orchideae 79 Orchideae 120
Gramineae 69 Gramineae 60
Cyperaceae 62 Compositae 60
Rubiaceae 57 Leguminosae 36
Euphorbiaceae 45 Rubiaceae 24
Compositae 43 Cyperaceae 24
Leguminosae 41 Euphorbiaceae 18
The cause of the great preponderance of ferns in oceanic islands has
already been discussed in my book on _Tropical Nature_; and we have seen
that Mauritius, Bourbon, and Rodriguez must be classed as such, though from
their proximity to Madagascar they have to be considered as satellites to
that great island. The abundance of orchids, the reverse of what occurs in
remoter oceanic islands, may be in part due to analogous causes. Their
usually minute and abundant seeds would be as easily carried by the wind as
the spores of ferns, and their frequent epiphytic habit affords them an
endless variety of stations on which to vegetate, and at the same time
removes them in a great measure from the competition of other plants. When,
therefore, the climate is sufficiently moist and equable, and there is a
luxuriant forest vegetation, we may expect to find orchids plentiful on
such tropical islands as possess an abundance of insects adapted to
fertilise them, and which are not too far removed from other lands or
continents from which their seeds might be conveyed.
_Concluding Remarks on Madagascar and the Mascarene Islands._--There is
probably no portion of the globe that contains within itself so many and
such varied features of interest connected with geographical distribution,
or which so well illustrates the mode of solving the problems it presents,
as the comparatively small insular region which comprises the great island
of Madagascar and the smaller islands and island-groups which immediately
surround it. In Madagascar we have a continental island of the first rank,
and undoubtedly of immense antiquity; we have detached fragments of this
island in the Comoros and {447} Aldabra; in the Seychelles we have the
fragments of another very ancient island, which may perhaps never have been
continental; in Mauritius, Bourbon, and Rodriguez we have three undoubtedly
oceanic islands; while in the extensive banks and coral reefs of Cargados,
Saya de Malha, the Chagos, and the Maldive Isles, we have indications of
the submergence of many large islands which may have aided in the
transmission of organisms from the Indian Peninsula. But between and around
all these islands we have depths of 2,500 fathoms and upwards, which
renders it very improbable that there has ever been here a continuous land
surface, at all events during the Tertiary or Secondary periods of geology.
It is most interesting and satisfactory to find that this conclusion,
arrived at solely by a study of the form of the sea-bottom and the general
principle of oceanic permanence, is fully supported by the evidence of the
organic productions of the several islands; because it gives us confidence
in those principles, and helps to supply us with a practical demonstration
of them. We find that the entire group contains just that amount of Indian
forms which could well have passed from island to island; that many of
these forms are slightly modified species, indicating that the migration
occurred during late Tertiary times, while others are distinct genera,
indicating a more ancient connection; but in no one case do we find animals
which necessitate an actual land-connection, while the numerous Indian
types of mammalia, reptiles, birds, and insects, which must certainly have
passed over had there been such an actual land-connection, are totally
wanting. The one fact which has been supposed to require such a
connection--the distribution of the lemurs--can be far more naturally
explained by a general dispersion of the group from Europe, where we know
it existed in Eocene times; and such an explanation applies equally to the
affinity of the Insectivora of Madagascar and Cuba; the snakes
(Herpetodryas, &c.) of Madagascar and America; and the lizards
(Cryptoblepharus) of Mauritius and Australia. To suppose, in all these
cases, and in many others, a direct land-connection, is really absurd,
because {448} we have the evidence afforded by geology of wide differences
of distribution directly we pass beyond the most recent deposits; and when
we go back to Mesozoic--and still more to Palaeozoic--times, the majority
of the groups of animals and plants appear to have had a world-wide range.
A large number of our European Miocene genera of vertebrates were also
Indian or African, or even American; the South American Tertiary fauna
contained many European types; while many Mesozoic reptiles and mollusca
ranged from Europe and North America to Australia and New Zealand.
By very good evidence (the occurrence of wide areas of marine deposits of
Eocene age), geologists have established the fact that Africa was cut off
from Europe and Asia by an arm of the sea in early Tertiary times, forming
a large island-continent. By the evidence of abundant organic remains we
know that all the types of large mammalia now found in Africa (but which
are absent from Madagascar) inhabited Europe and Asia, and many of them
also North America, in the Miocene period. At a still earlier epoch Africa
may have received its lower types of mammals--lemurs, insectivora, and
small carnivora, together with its ancestral struthious birds, and its
reptiles and insects of American or Australian affinity; and at this period
it was joined to Madagascar. Before the later continental period of Africa,
Madagascar had become an island; and thus, when the large mammalia from the
northern continent overran Africa, they were prevented from reaching
Madagascar, which thenceforth was enabled to develop its singular forms of
low-type mammalia, its gigantic ostrich-like Aepyornis, its isolated birds,
its remarkable insects, and its rich and peculiar flora. From it the
adjacent islands received such organisms as could cross the sea; while they
transmitted to Madagascar some of the Indian birds and insects which had
reached them.
The method we have followed in these investigations is to accept the
results of geological and palaeontological science, and the ascertained
facts as to the powers of dispersal of the various animal groups; to take
full account of the laws of evolution as affecting distribution, {449} and
of the various ocean depths as implying recent or remote union of islands
with their adjacent continents; and the result is, that wherever we possess
a sufficient knowledge of these various classes of evidence, we find it
possible to give a connected and intelligible explanation of all the most
striking peculiarities of the organic world. In Madagascar we have
undoubtedly one of the most difficult of these problems; but we have, I
think, fairly met and conquered most of its difficulties. The complexity of
the organic relations of this island is due, partly to its having derived
its animal forms from two distinct sources--from one continent through a
direct land-connection, and from another by means of intervening islands
now submerged; but, mainly to the fact of its having been separated from a
continent which is now, zoologically, in a very different condition from
that which prevailed at the time of the separation; and to its having been
thus able to preserve a number of types which may date back to the Eocene,
or even to the Cretaceous, period. Some of these types have become
altogether extinct elsewhere; others have spread far and wide over the
globe, and have survived only in a few remote countries--and especially in
those which have been more or less secured by their isolated position from
the incursions of the more highly-developed forms of later times. This
explains why it is that the nearest allies of the Madagascar fauna and
flora are now so often to be found in South America or Australia--countries
in which low forms of mammalia and birds still largely prevail;--it being
on account of the long-continued isolation of all these countries that
similar forms (descendants of ancient types) are preserved in them. Had the
numerous suggested continental extensions connecting these remote
continents at various geological periods been realities, the result would
have been that all these interesting archaic forms, all these defenceless
insular types, would long ago have been exterminated, and one comparatively
monotonous fauna have reigned over the whole earth. So far from explaining
the anomalous facts, the alleged continental extensions, had they existed,
would have left no such facts to be explained.
* * * * *
{450}
CHAPTER XX
ANOMALOUS ISLANDS: CELEBES
Anomalous Relations of Celebes--Physical Features of the
Island--Zoological Character of the Islands Around Celebes--The Malayan
and Australian Banks--Zoology of Celebes: Mammalia--Probable Derivation
of the Mammals of Celebes--Birds of Celebes--Bird-types Peculiar to
Celebes--Celebes not Strictly a Continental Island--Peculiarities of
the Insects of Celebes--Himalayan Types of Birds and Butterflies in
Celebes--Peculiarities of Shape and Colour of Celebesian
Butterflies--Concluding Remarks--Appendix on the Birds of Celebes.
The only other islands of the globe which can be classed as "ancient
continental" are the larger Antilles (Cuba, Haiti, Jamaica, and Porto
Rico), Iceland, and perhaps Celebes. The Antilles have been so fully
discussed and illustrated in my former work, and there is so little fresh
information about them, that I do not propose to treat of them here,
especially as they fall short of Madagascar in all points of biological
interest, and offer no problems of a different character from such as have
already been sufficiently explained.
Iceland, also, must apparently be classed as belonging to the "Ancient
Continental Islands," for though usually described as wholly volcanic, it
is, more probably, an island of varied geological structure buried under
the lavas of its numerous volcanoes. But of late years extensive Tertiary
deposits of Miocene age have been discovered, showing that it is not a mere
congeries of {451} volcanoes; it is connected with the British Islands and
with Greenland by seas less than 500 fathoms deep; and it possesses a few
mammalia, one of which is peculiar, and at least three peculiar species of
birds. It was therefore almost certainly united with Greenland, and
probably with Europe by way of Britain, in the early part of the Tertiary
period, and thus afforded one of the routes by which that intermigration of
American and European animals and plants was effected which we know
occurred during some portion of the Eocene and Miocene periods, and
probably also in the Pliocene. The fauna and flora of this island are,
however, so poor, and offer so few peculiarities, that it is unnecessary to
devote more time to their consideration.
There remains the great Malay island--Celebes, which, owing to its
possession of several large and very peculiar mammalia, must be classed,
zoologically, as "ancient continental"; but whose central position and
relations both to Asia and to Australia render it very difficult to decide
in which of the primary zoological regions it ought to be placed, or
whether it has ever been united with either of the great continents.
Although I have pretty fully discussed its zoological peculiarities and
past history in my _Geographical Distribution of Animals_, it seems
advisable to review the facts on the present occasion, more especially as
the systematic investigation of the characteristics of continental islands
we have now made will place us in a better position for determining its
true zoo-geographical relations.
_Physical Features of Celebes._--This large and still comparatively
unexplored island is interesting to the geographer on account of its
remarkable outline, but much more so to the zoologist for its curious
assemblage of animal forms. The geological structure of Celebes is almost
unknown. The extremity of the northern peninsula is volcanic; while in the
southern peninsula there are extensive deposits of a crystalline limestone,
in some places overlying basalt. Gold is found in the northern peninsula
and in the central mass, as well as iron, tin, and copper in small
quantities; so that there can be little {452} doubt that the mountain
ranges of the interior consist of ancient stratified rocks.
[Illustration: MAP OF CELEBES AND THE SURROUNDING ISLANDS.
The depth of sea is shown by three tints: the lightest indicating less than
100 fathoms, the medium tint less than 1,000 fathoms, and the dark tint
more than 1,000 fathoms. The figures show depths in fathoms.]
It is not yet known whether Celebes is completely separated from the
surrounding islands by a deep sea, but {453} the facts at our command
render it probable that it is so. The northern and eastern portions of the
Celebes Sea have been ascertained to be from 2,000 to 2,600 fathoms deep,
and such depths may extend over a considerable portion of it, or even be
much exceeded in the centre. In the Molucca passage a single sounding on
the Gilolo side gave 1,200 fathoms, and a large part of the Molucca and
Banda Seas probably exceed 2,000 fathoms. The southern portion of the
Straits of Macassar is full of coral reefs, and a shallow sea of less than
100 fathoms extends from Borneo to within about forty miles of the western
promontory of Celebes; but farther north there is deep water close to the
shore, and it seems probable that a deep channel extends quite through the
straits, which have no doubt been much shallowed by the deposits from the
great Bornean rivers as well as by those of Celebes itself. Southward
again, the chain of volcanic islands from Bali to Timor appears to rise out
of a deep ocean, the few soundings we possess showing depths of from 670 to
1,300 fathoms almost close to their northern shores. We seem justified,
therefore, in concluding that Celebes is entirely surrounded by a deep sea,
which has, however, become partially filled up by river deposits, by
volcanic upheaval, or by coral reefs. Such shallows, where they exist, may
therefore be due to antiquity and isolation, instead of being indications
of a former union with any of the surrounding islands.
_Zoological Character of the Islands around Celebes._--In order to have a
clear conception of the peculiar character of the Celebesian fauna, we must
take into account that of the surrounding countries from which we may
suppose it to have received immigrants. These we may divide broadly into
two groups, those on the west belonging to the Oriental region of our
zoological geography, and those on the east belonging to the Australian
region. Of the first group Borneo is a typical representative; and from its
proximity and the extent of its opposing coasts it is the island which we
should expect to show most resemblance to Celebes. We have already seen
that the fauna of Borneo is essentially the same as that of Southern Asia,
and that it is excessively rich in all the Malayan types of {454} mammalia
and birds. Java and Bali closely resemble Borneo in general character,
though somewhat less rich and with several peculiar forms; while the
Philippine Islands, though very much poorer, and with a greater amount of
speciality, yet exhibit essentially the same character. These islands,
taken as a whole, may be described as having a fauna almost identical with
that of Southern Asia; for no family of mammalia is found in the one which
is absent from the other, and the same may be said, with very few and
unimportant exceptions, of the birds; while hundreds of genera and of
species are common to both.
In the islands east and south of Celebes--the Moluccas, New Guinea, and the
Timor group from Lombok eastward--we find, on the other hand, the most
wonderful contrast in the forms of life. Of twenty-seven families of
terrestrial mammals found in the great Malay islands, all have disappeared
but four, and of these it is doubtful whether two have not been introduced
by man. We also find here four families of Marsupials, all totally unknown
in the western islands. Even birds, though usually more widely spread, show
a corresponding difference, about eleven Malayan families being quite
unknown east of Celebes, where six new families make their appearance which
are equally unknown to the westward.[115]
We have here a radical difference between two sets of islands not very far
removed from each other, the one set belonging zoologically to Asia, the
other to Australia. The Asiatic or Malayan group is found to be bounded
strictly by the eastward limits of the great bank (for the most part less
than fifty fathoms below the surface) which {455} stretches out from the
Siamese and Malayan peninsula as far as Java, Sumatra, Borneo, and the
Philippines. To the east another bank unites New Guinea and the Papuan
Islands as far as Aru, Mysol, and Waigiou, with Australia; while the
Moluccas and Timor groups are surrounded by much deeper water, which forms,
in the Banda and Celebes Seas and perhaps in other parts of this area,
great basins of enormous depths (2,000 to 3,000 fathoms or even more)
enclosed by tracts under a thousand fathoms, which separate the basins from
each other and from the adjacent Pacific and Indian Oceans (see map). This
peculiar formation of the sea-bottom probably indicates that this area has
been the seat of great local upheavals and subsidences; and it is quite in
accordance with this view that we find the Moluccas, while closely agreeing
with New Guinea in their forms of life, yet strikingly deficient in many
important groups, and exhibiting an altogether poverty-stricken appearance
as regards the higher animals. It is a suggestive fact that the Philippine
Islands bear an exactly parallel relation to Borneo, being equally
deficient in many of the higher groups; and here too, in the Sooloo Sea, we
find a similar enclosed basin of great depth. Hence we may in both cases
connect, on the one hand, the extensive area of land-surface and of
adjacent shallow sea with a long period of stability and a consequent rich
development of the forms of life; and, on the other hand, a highly broken
land-surface with the adjacent seas of great but very unequal depths, with
a period of disturbance, probably involving extensive submersions of the
land, resulting in a scanty and fragmentary vertebrate fauna.
_Zoology of Celebes._--The zoology of Celebes differs so remarkably from
that of both the great divisions of the Archipelago above indicated, that
it is very difficult to decide in which to place it. It possesses only
about sixteen species of terrestrial mammalia, so that it is at once
distinguished from Borneo and Java by its extreme poverty in this class. Of
this small number four belong to the Moluccan and Australian fauna--there
being two marsupials of the genus Cuscus, and two forest rats said to be
allied to Australian types. {456}
The remaining twelve species are, generally speaking, of Malayan or Asiatic
types, but some of them are so peculiar that they have no near allies in
any part of the world; while the rest are of the ordinary Malay type or
even identical with Malayan species, and some of these may be recent
introductions through human agency. These twelve species of Asiatic type
will be now enumerated. They consist of five peculiar squirrels--a group
unknown farther east; a peculiar species of wild pig; a deer so closely
allied to the _Cervus hippelaphus_ of Borneo that it may well have been
introduced by man both here and in the Moluccas; a civet, _Viverra
tangalunga_, common in all the Malay Islands, and also perhaps introduced;
the curious Malayan tarsier (_Tarsius spectrum_) said to be only found in a
small island off the coast;--and besides these, three remarkable animals,
all of large size and all quite unlike anything found in the Malay Islands
or even in Asia. These are a black and almost tailless baboon-like ape
(_Cynopithecus nigrescens_); an antelopean buffalo (_Anoa depressicornis_),
and the strange babirusa (_Babirusa alfurus_).
None of these three animals last mentioned has any close allies elsewhere,
and their presence in Celebes may be considered the crucial fact which must
give us the clue to the past history of the island. Let us then see what
they teach us. The ape is apparently somewhat intermediate between the
great baboons of Africa and the short-tailed macaques of Asia, but its
cranium shows a nearer approach to the former group, in its flat projecting
muzzle, large superciliary crests, and maxillary ridges. The anoa, though
anatomically allied to the buffaloes, externally more resembles the bovine
antelopes of Africa; while the babirusa is altogether unlike any other
living member of the swine family, the canines of the upper jaws growing
directly upwards like horns, forming a spiral curve over the eyes, instead
of downwards, as in all other mammalia. An approach to this peculiarity is
made by the African wart-hogs, in which the upper tusk grows out laterally
and then curves up; but these animals are not otherwise closely allied to
the babirusa. {457}
_Probable Derivation of the Mammals of Celebes._--It is clear that we have
here a group of extremely peculiar, and, in all probability, very ancient
forms, which have been preserved to us by isolation in Celebes, just as the
monotremes and marsupials have been preserved in Australia, and so many of
the lemurs and Insectivora in Madagascar. And this compels us to look upon
the existing island as a fragment of some ancient land, once perhaps
forming part of the great northern continent, but separated from it far
earlier than Borneo, Sumatra, and Java. The exceeding scantiness of the
mammalian fauna, however, remains to be accounted for. We have seen that
Formosa, a much smaller island, contains more than twice as many species;
and we may be sure that at the time when such animals as apes and buffaloes
existed, the Asiatic continent swarmed with varied forms of mammals to
quite as great an extent as Borneo does now. If the portion of separated
land had been anything like as large as Celebes now is, it would certainly
have preserved a far more abundant and varied fauna. To explain the facts
we have the choice of two theories:--either that the original island has
since its separation been greatly reduced by submersion, so as to lead to
the extinction of most of the higher land animals; or, that it originally
formed part of an independent land stretching eastward, and was only united
with the Asiatic continent for a short period, or perhaps even never united
at all, but so connected by intervening islands separated by narrow straits
that a few mammals might find their way across. The latter supposition
appears best to explain the facts. The three animals in question are such
as might readily pass over narrow straits from island to island; and we are
thus better enabled to understand the complete absence of the arboreal
monkeys, of the Insectivora, and of the very numerous and varied Carnivora
and Rodents of Borneo, all of which except the squirrels are entirely
unrepresented in Celebes by any peculiar and ancient forms.
The question at issue can only be finally determined by geological
investigations. If Celebes has once formed part of Asia, and participated
in its rich mammalian fauna, which has been since destroyed by submergence,
then some {458} remains of this fauna must certainly be preserved in caves
or late Tertiary deposits, and proofs of the submergence itself will be
found when sought for. If, on the other hand, the existing animals fairly
represent those which have ever reached the island, then no such remains
will be discovered, and there need be no evidence of any great and
extensive subsidence in late Tertiary times.
_Birds of Celebes._--Having thus clearly placed before us the problem
presented by the mammalian fauna of Celebes, we may proceed to see what
additional evidence is afforded by the birds and any other groups of which
we have sufficient information. About 164 species of true land-birds are
now known to inhabit the island of Celebes itself. Considerably more than
half of these (ninety-four species) are peculiar to it; twenty-nine are
found also in Borneo and the other Malay Islands, to which they specially
belong; while sixteen are common to the Moluccas or other islands of the
Australian region; the remainder being species of wide range and not
characteristic of either division of the Archipelago. We have here a large
preponderance of western over eastern species of birds inhabiting Celebes,
though not to quite so great an extent as in the mammalia; and the
inference to be drawn from this fact is, simply, that more birds have
migrated from Borneo than from the Moluccas--which is exactly what we might
expect both from the greater extent of the coast of Borneo opposite that of
Celebes, and also from the much greater richness in species of the Bornean
than the Moluccan bird-fauna.
It is, however, to the relations of the peculiar species of Celebesian
birds that we must turn, in order to ascertain the origin of the fauna in
past times; and we must look to the source of the generic types which they
represent to give us this information. The ninety-four peculiar species
above noted belong to about sixty-six genera, of which about twenty-three
are common to the whole Archipelago, and have therefore little
significance. Of the remainder, twelve are altogether peculiar to Celebes;
twenty-one are Malayan, but not Moluccan or Australian; while ten are
Moluccan or Australian, but not Malayan. This {459} proportion does not
differ much from that afforded by the non-peculiar species; and it teaches
us that, for a considerable period, Celebes has been receiving immigrants
from all sides, many of which have had time to become modified into
distinct representative species. These evidently belong to the period
during which Borneo on the one side, and the Moluccas on the other, have
occupied very much the same relative position as now. There remain the
twelve peculiar Celebesian genera, to which we must look for some further
clue as to the origin of the older portion of the fauna; and as these are
especially interesting we must examine them somewhat closely.
_Bird-types Peculiar to Celebes._--First we have Artamides, one of the
Campephaginae or caterpillar-shrikes--a not very well-marked genus, and
which may have been derived, either from the Malayan or the Moluccan side
of the Archipelago. Two peculiar genera of kingfishers--Monachalcyon and
Cittura--seem allied, the former to the widespread Todiramphus and to the
Caridonax of Lombok, the latter to the Australian Melidora. Another
kingfisher, Ceycopsis, combines the characters of the Malayan Ceyx and the
African Ispidina, and thus forms an example of an ancient generalised form
analogous to what occurs among the mammalia. Streptocitta is a peculiar
form allied to the magpies; while Basilornis (found also in Ceram), Enodes,
and Scissirostrum, are very peculiar starlings, the latter altogether
unlike any other bird, and perhaps forming a distinct sub-family. Meropogon
is a peculiar bee-eater, allied to the Malayan Nyctiornis; Rhamphococyx is
a modification of Phaenicophaes, a Malayan genus of cuckoos; Prioniturus
(found also in the Philippines) is a genus of parrots distinguished by
raquet-formed tail feathers, altogether unique in the order; while
Megacephalon is a remarkable and very isolated form of the Australian
Megapodiidae, or mound-builders.
Omitting those whose affinity may be pretty clearly traced to groups still
inhabiting the islands of the western or the eastern half of the
Archipelago, we find four birds which have no near allies at all, but
appear to be either ancestral forms, or extreme modifications, of Asiatic
or {460} African birds--Basilornis, Enodes, Scissirostrum, Ceycopsis. These
may fairly be associated with the baboon-ape, anoa, and babirusa, as
indicating extreme antiquity and some communication with the Asiatic
continent at a period when the forms of life and their geographical
distribution differed considerably from what they are at the present time.
But here again we meet with exactly the same difficulty as in the mammalia,
in the comparative poverty of the types of birds now inhabiting Celebes.
Although the preponderance of affinity, especially in the case of its more
ancient and peculiar forms, is undoubtedly with Asia rather than with
Australia; yet, still more decidedly than in the case of the mammalia, are
we forbidden to suppose that it ever formed a part of the old Asiatic
continent, on account of the _total_ absence of so many important and
extensive groups of Asiatic birds. It is not single species or even genera,
but whole families that are thus absent, and among them families which are
pre-eminently characteristic of all tropical Asia. Such are the Timaliidae,
or babblers, of which there are twelve genera in Borneo, and nearly thirty
genera in the Oriental Region, but of which one species only, hardly
distinguishable from a Malayan form, inhabits Celebes; the Phyllornithidae,
or green bulbuls, and the Pycnonotidae, or bulbuls, both absolutely
ubiquitous in tropical Asia and Malaya, but unknown in Celebes; the
Eurylaemidae, or gapers, found everywhere in the great Malay Islands; the
Megalaemidae, or barbets; the Trogonidae, or trogons; and the Phasianidae,
or pheasants, all pre-eminently Asiatic and Malayan but all absent from
Celebes, with the exception of the common jungle-fowl, which, owing to the
passion of Malays for cock-fighting, may have been introduced. To these
important _families_ may be added Asiatic and Malayan _genera_ by the
score; but, confining ourselves to these seven ubiquitous families, we must
ask,--Is it possible, that, at the period when the ancestors of the
peculiar Celebes mammals entered the island, and when the forms of life,
though distinct, could not have been quite unlike those now living, it
could have actually formed a part of the continent without {461} possessing
representatives of the greater part of these extensive and important
families of birds? To get rid altogether of such varied and dominant types
of bird-life by any subsequent process of submersion is more difficult than
to exterminate mammalia; and we are therefore again driven to our former
conclusion--that the present land of Celebes has never (in Tertiary times)
been united to the Asiatic continent, but has received its population of
Asiatic forms by migration across narrow straits and intervening islands.
Taking into consideration the amount of affinity on the one hand, and the
isolation on the other, of the Celebesian fauna, we may probably place the
period of this earlier migration in the early part of the latter half of
the Tertiary period, that is, in middle or late Miocene times.
_Celebes not Strictly a Continental Island._--A study of the mammalian and
of the bird-fauna of Celebes thus leads us in both cases to the same
conclusion, and forbids us to rank it as a strictly continental island on
the Asiatic side. But facts of a very similar character are equally opposed
to the idea of a former land-connection with Australia or New Guinea, or
even with the Moluccas. The numerous marsupials of those countries are all
wanting in Celebes, except the phalangers of the genus Cuscus, and these
arboreal creatures are very liable to be carried across narrow seas on
trees uprooted by earthquakes or floods. The terrestrial cassowaries are
equally absent; and thus we can account for the presence of all the
Moluccan or Australian types actually found in Celebes without supposing
any land-connection on this side during the Tertiary period. The presence
of the Celebes ape in the island of Batchian, and of the babirusa in Bouru,
can be sufficiently explained by a somewhat closer approximation of the
respective lands, or by a few intervening islands which have since
disappeared, or it may even be due to human agency.
If the explanation now given of the peculiar features presented by the
fauna of Celebes be the correct one, we are fully justified in classing it
as an "anomalous island," since it possesses a small but very remarkable
mammalian fauna, without ever having been directly united with any {462}
continent or extensive land; and, both by what it has and what it wants,
occupies such an exactly intermediate position between the Oriental and
Australian regions that it will perhaps ever remain a mere matter of
opinion with which it should properly be associated. Forming, as it does,
the western limit of such typical Australian groups as the Marsupials among
mammalia, and the Trichoglossidae and Meliphagidae among birds, and being
so strikingly deficient in all the more characteristic Oriental families
and genera of both classes, I have always placed it in the Australian
Region; but it may perhaps with equal propriety be left out of both till a
further knowledge of its geology enables us to determine its early history
with more precision.
_Peculiarities of the Insects of Celebes._--The only other class of animals
in Celebes, of which we have a tolerable knowledge, is that of insects,
among which we meet with peculiarities of a very remarkable kind, and such
as are found in no other island on the globe. Having already given a full
account of some of these peculiarities in a paper read before the Linnean
Society--republished in my _Contributions to the Theory of Natural
Selection_,--while others have been discussed in my _Geographical
Distribution of Animals_ (Vol. I. p. 434)--I will only here briefly refer
to them in order to see whether they accord with, or receive any
explanation from, the somewhat novel view of the past history of the island
here advanced.
The general distribution of the two best known groups of insects--the
butterflies and the beetles--agrees very closely with that of the birds and
mammalia, inasmuch as Celebes forms the eastern limit of a number of
Asiatic and Malayan genera, and at the same time the western limit of
several Moluccan and Australian genera, the former perhaps preponderating
as in the higher animals.
_Himalayan Types of Birds and Butterflies in Celebes._--A curious fact of
distribution exhibited both among butterflies and birds, is the occurrence
in Celebes of species and genera unknown to the adjacent islands, but only
found again when we reach the Himalayan mountains or the Indian Peninsula.
Among birds we have a small yellow {463} flycatcher (_Myialestes
helianthea_), a flower-pecker (_Pachyglossa aureolimbata_), a finch (_Munia
brunneiceps_), and a roller (_Coracias temminckii_), all closely allied to
Indian (not Malayan) species,--all the genera, except Munia, being, in
fact, unknown in any Malay island. An exactly parallel case is that of a
butterfly of the genus Dichorrhagia, which has a very close ally in the
Himalayas, but nothing like it in any intervening country. These facts call
to mind the similar case of Formosa, where some of its birds and mammals
occurred again, under identical or closely allied forms, in the Himalayas;
and in both instances they can only be explained by going back to a period
when the distribution of these forms was very different from what it is
now.
_Peculiarities of Shape and Colour in Celebesian Butterflies._--Even more
remarkable are the peculiarities of shape and colour in a number of
Celebesian butterflies of different genera. These are found to vary all in
the same manner, indicating some general cause of variation able to act
upon totally distinct groups, and produce upon them all a common result.
Nearly thirty species of butterflies, belonging to three different
families, have a common modification in the shape of their wings, by which
they can be distinguished at a glance from their allies in any other island
or country whatever; and all these are larger than the representative forms
inhabiting most of the adjacent islands.[116] No such remarkable local
modification as this is known to occur in any other part of the globe; and
whatever may have been its cause, that cause must certainly have been long
in action, and have been confined to a limited area. We have here,
therefore, another argument in favour of the long-continued isolation of
Celebes from all the surrounding islands and continents--a hypothesis which
we have seen to afford the best, if not the only, explanation of its
peculiar vertebrate fauna.
_Concluding Remarks._--If the view here given of the origin of the
remarkable Celebesian fauna is correct, we have in this island a fragment
of the great eastern {464} continent which has preserved to us, perhaps
from Miocene times, some remnants of its ancient animal forms. There is no
other example on the globe of an island so closely surrounded by other
islands on every side, yet preserving such a marked individuality in its
forms of life; while, as regards the special features which characterise
its insects, it is, so far as yet known, absolutely unique. Unfortunately
very little is known of the botany of Celebes, but it seems probable that
its plants will to some extent partake of the speciality which so markedly
distinguishes its animals; and there is here a rich field for any botanist
who is able to penetrate to the forest-clad mountains of its interior.
{465}
APPENDIX TO CHAPTER XX
The following list of the Land Birds of Celebes and the adjacent islands
which partake of its zoological peculiarities, in which are incorporated
all the species discovered up to 1890, has been drawn up from the following
sources:--
1. A List of the Birds known to inhabit the Island of Celebes, By
Arthur, Viscount Walden, F.R.S. (Trans. Zool. Soc. 1872. Vol. viii. pt.
ii.)
2. Intorno al Genere Hermotimia. (Rchb.) Nota di Tommaso Salvadori.
(Atti della Reale Accademia delle Scienze di Torino. Vol x. 1874.)
3. Intorno a due Collezioni di Ucelli di Celebes--Note di Tommaso
Salvadori. (Annali del Mus. Civ. di St. Nat. di Genova. Vol. vii.
1875.)
4. Beitraege zur Ornithologie von Celebes und Sangir. Von Dr. Friedrich
Brueggemann. Bremen, 1876.
5. Intorno a due piccole Collezioni di Ucelli di Isole Sanghir e di
Tifore. Nota di Tommaso Salvadori. (Annali del Mus. Civ. di St. Nat. di
Genova. Vol. ix. 1876-77.)
6. Intorno alle Specie di Nettarinie delle Molucche e del Gruppo di
Celebes. Note di Tommaso Salvadori. (Atti della Reale Accad. delle
Scienze di Torino. Vol. xii. 1877.)
7. Descrizione di tre Nuove Specie di Ucelli, e note intorno ad altre
poco conosciute delle Isole Sanghir. Per Tommaso Salvadori. (L. c. Vol.
xiii. 1878.)
8. Field Notes on the Birds of Celebes. By A. B. Meyer, M.D., &c.
(Ibis, 1879.)
9. On the Collection of Birds made by Dr. Meyer during his Expedition
to New Guinea and some neighbouring Islands. By R. Boulder Sharpe.
(Mitth. d. kgl. Zool. Mus. Dresden, 1878. Heft 3.) New species from the
Sula and Sanghir Islands are described.
10. List of Birds from the Sula Islands (East of Celebes) with
Descriptions of the New Species. By Alfred Russel Wallace, F.Z.S.
(_Proc. Zool. Soc._ 1862, p. 333.)
11. The Zoological Record, and "The Ibis" to 1890.
{466}
LIST OF LAND BIRDS OF CELEBES
_N.B.--The Species marked with an * are not included in Viscount Walden's
list. For these only, an authority is usually given._