SUMMARY OF THE DISTRIBUTION AND LINES OF MIGRATION OF THE SEVERAL
CLASSES OF ANIMALS.
Mammalia (p. 540)--Lines of Migration of the Mammalia (p. 544)--Birds
(p. 545)--Reptiles (p. 547)--Amphibia (p. 548)--Fresh-water Fishes
(p. 549)--Insects (p. 550)--Terrestrial Mollusca (p. 551)--Conclusion
(p. 552) 540-553
GENERAL INDEX 557
MAPS AND ILLUSTRATIONS IN VOL. II.
_To face page_
1. Map of the Neotropical Region 3
2. Plate XIV. A Brazilian Forest with Characteristic Mammalia 24
3. Plate XV. A Scene on the Upper Amazon, with some Characteristic
Birds 28
4. Plate XVI. The Chilian Andes, with Characteristic Animals 40
5. Plate XVII. A Scene in Cuba, with Characteristic Animals 67
6. Map of the Nearctic Region 115
7. Plate XVIII. Scene in California with some Characteristic Birds 128
8. Plate XIX. The North American Prairies with Characteristic
Mammalia 130
9. Plate XX. A Canadian Forest with Characteristic Mammalia 136
ERRATA IN VOL. II.
As in Vol. I. mis-spellings are not given here, being mostly corrected in
the Index.
Page 111, No. 642, _for_ 1 _read_ 2.
" 111, No. 643, _for_ 15 _read_ 9.
" 267, line 7, _add_ Borneo.
" 276, line 10, _for_ 16 Genera _read_ 11 Genera.
" " 8 lines from foot, for _Drepanornis_ read _Neodrepanis_.
" 291, 5 lines from foot, for _Sayornis_ read _Empidias_.
THE
GEOGRAPHICAL DISTRIBUTION
OF ANIMALS.
PART III. (_continued._)
_ZOOLOGICAL GEOGRAPHY:_
_A REVIEW OF THE CHIEF FORMS OF ANIMAL LIFE IN THE SEVERAL REGIONS AND
SUB-REGIONS, WITH THE INDICATIONS THEY AFFORD OF GEOGRAPHICAL MUTATIONS._
[Illustration: NEOTROPICAL REGION]
{3}CHAPTER XIV.
THE NEOTROPICAL REGION.
This region, comprehending not only South America but Tropical North
America and the Antilles, may be compared as to extent with the Ethiopian
region; but it is distinguished from all the other great zoological
divisions of the globe, by the small proportion of its surface occupied by
deserts, by the large proportion of its lowlands, and by the altogether
unequalled extent and luxuriance of its tropical forests. It further
possesses a grand mountain range, rivalling the Himalayas in altitude and
far surpassing them in extent, and which, being wholly situated within the
region and running through eighty degrees of latitude, offers a variety of
conditions and an extent of mountain slopes, of lofty plateaus and of deep
valleys, which no other tropical region can approach. It has a further
advantage in a southward prolongation far into the temperate zone,
equivalent to a still greater extension of its lofty plateaus; and this
has, no doubt, aided the development of the peculiar alpine forms of life
which abound in the southern Andes. The climate of this region is
exceptionally favourable. Owing to the lofty mountain range situated along
its western margin, the moisture-laden trade winds from the Atlantic have
free access to the interior. A sufficient proportion of this moisture
reaches the higher slopes of the Andes, where its condensation gives rise
to innumerable streams, which cut deep ravines and carry down such an
amount of sediment, that they have formed the vast plains of the Amazon, of
{4}Paraguay, and of the Orinooko out of what were once, no doubt, arms of
the sea, separating the large islands of Guiana, Brazil, and the Andes.
From these concurrent favourable conditions, there has resulted that
inexhaustible variety of generic and specific forms with a somewhat limited
range of family and ordinal types, which characterise neotropical zoology
to a degree nowhere else to be met with.
Together with this variety and richness, there is a remarkable uniformity
of animal life over all the tropical continental portions of the region, so
that its division into sub-regions is a matter of some difficulty. There
is, however, no doubt about separating the West Indian islands as forming a
well-marked subdivision; characterised, not only by that poverty of forms
which is a general feature of ancient insular groups, but also by a number
of peculiar generic types, some of which are quite foreign to the remainder
of the region. We must exclude, however, the islands of Trinidad, Tobago,
and a few other small islands near the coast, which zoologically form a
part of the main land. Again, the South Temperate portion of the continent,
together with the high plateaus of the Andes to near the equator, form a
well-marked subdivision, characterised by a peculiar fauna, very distinct
both positively and negatively from that of the tropical lowland districts.
The rest of Tropical South America is so homogeneous in its forms of life
that it cannot be conveniently subdivided for the purposes of a work like
the present. There are, no doubt, considerable differences in various parts
of its vast area, due partly to its having been once separated into three
or more islands, in part to existing diversities of physical conditions;
and more exact knowledge may enable us to form several provinces or perhaps
additional sub-regions. A large proportion of the genera, however, when
sufficiently numerous in species, range over almost the whole extent of
this sub-region wherever the conditions are favourable. Even the Andes do
not seem to form such a barrier as has been supposed. North of the equator,
where its western slopes are moist and forest-clad, most of the genera are
found on both sides. To the south of this line its western valleys are arid
and its lower plains almost deserts; and thus the absence of a {5}number of
groups to which verdant forests are essential, can be traced to the
unsuitable conditions rather than to the existence of the mountain barrier.
All Tropical South America, therefore, is here considered to form but one
sub-region.
The portion of North America that lies within the tropics, closely
resembles the last sub-region in general zoological features. It possesses
hardly any positive distinctions; but there are several of a negative
character, many important groups being wholly confined to South America. On
the other hand many genera range into Mexico and Guatemala from the north,
which never reach South America; so that it is convenient to separate this
district as a sub-region, which forms, to some extent, a transition to the
Nearctic region.
_General Zoological Features of the Neotropical Region._--Richness combined
with isolation is the predominant feature of Neotropical zoology, and no
other region can approach it in the number of its peculiar family and
generic types. It has eight families of Mammalia absolutely confined to it,
besides several others which are rare elsewhere. These consist of two
families of monkeys, Cebidæ and Hapalidæ, both abounding in genera and
species; the Phyllostomidæ, or blood-sucking bats; Chinchillidæ and Caviidæ
among rodents; besides the greater part of the Octodontidæ, Echimyidæ and
Cercolabidæ. Among edentata, it has Bradypodidæ, or sloths, Dasypodidæ, or
armadillos, and Myrmecophagidæ, or anteaters, constituting nearly the
entire order; while Procyonidæ, belonging to the carnivora, and
Didelphyidæ, a family of marsupials, only extend into the Nearctic region.
It has also many peculiar groups of carnivora and of Muridæ, making a total
of full a hundred genera confined to the region. Hardly less remarkable is
the absence of many wide-spread groups. With the exception of one genus in
the West Indian islands and a _Sorex_ which reaches Guatemala and Costa
Rica, the Insectivora are wholly wanting; as is also the extensive and
wide-spread family of the Viverridæ. It has no oxen or sheep, and indeed no
form of ruminant except deer and llamas; neither do its vast forests and
grassy plains support a single form of non-ruminant ungulate, except the
tapir and the peccary.
{6}_Birds._--In birds, the Neotropical region is even richer and more
isolated. It possesses no less than 23 families wholly confined within its
limits, with 7 others which only extend into the Nearctic region. The names
of the peculiar families are: Cærebidæ, or sugar-birds; Phytotomidæ, or
plant-cutters; Pipridæ, or manakins; Cotingidæ, or chatterers;
Formicariidæ, or ant-thrushes; Dendrocolaptidæ, or tree-creepers;
Pteroptochidæ; Rhamphastidæ, or toucans; Bucconidæ, or puff-birds;
Galbulidæ, or jacamas; Todidæ, or todies; Momotidæ, or motmots;
Steatornithidæ, the guacharo, or oil-bird; Cracidæ, or curassows; Tinamidæ,
or tinamous; Opisthocomidæ, the hoazin; Thinocoridæ; Cariamidæ; Aramidæ;
Psophiidæ, or trumpeters; Eurypygidæ, or sun-bitterns; and Palamedeidæ, or
horned-screamers. The seven which it possesses in common with North America
are: Vireonidæ, or greenlets; Mniotiltidæ, or wood-warblers; Tanagridæ, or
tanagers; Icteridæ, or hang-nests; Tyrannidæ, or tyrant-shrikes;
Trochilidæ, or humming-birds; and Conuridæ, or macaws. Most of these
families abound in genera and species, and many are of immense extent; such
as Trochilidæ, with 115 genera, and nearly 400 species; Tyrannidæ, with
more than 60 genera and nearly 300 species; Tanagridæ, with 43 genera and
300 species; Dendrocolaptidæ with 43 genera and more than 200 species; and
many other very large groups. There are nearly 600 genera peculiar to the
Neotropical region; but in using this number as a basis of comparison with
other regions we must remember, that owing to several ornithologists having
made the birds of South America a special study, they have perhaps been
more minutely subdivided than in the case of other entire tropical regions.
_Distinctive Characters of Neotropical Mammalia._--It is important also to
consider the kind and amount of difference between the various animal forms
of this region and of the Old World. To begin with the Quadrumana, all the
larger American monkeys (Cebidæ) differ from every Old World group in the
possession of an additional molar tooth in each jaw; and it is in this
group alone that the tail is developed into a prehensile organ of wonderful
power, adapting the animals to a purely arboreal life. Four of the genera,
comprising more than half the {7}species, have the prehensile tail, the
remainder having this organ either short, or lax as in the Old World
monkeys. Other differences from Old World apes, are the possession of a
broad nasal septum, and a less opposable thumb; and the absence of
cheek-pouches, ischial callosities, and a bony ear-tube. The Hapalidæ, or
marmozets, agree with the Cebidæ in all these characters, but have others
in addition which still more widely separate them from the Simiidæ; such as
an additional premolar tooth, acute claws, and thumb not at all opposable;
so that the whole group of American monkeys are radically different from
the remainder of the order.
The Procyonidæ are a distinct family of Carnivora, which make up for the
scarcity of Mustelidæ in South America. The Suidæ are represented by the
very distinct genus _Dicotyles_ (Peccary) forming a separate sub-family,
and differing from all other genera in their dentition, the absence of tail
and of one of the toes of the hind feet, the possession of a dorsal gland,
and only two mammæ. The rodents are represented by the Chinchillidæ and
Caviidæ, the latter comprising the largest animals in the order. The
Edentata are almost wholly confined to this region; and the three families
of the sloths (Bradypodidæ), armadillos (Dasypodidæ), and ant-eaters
(Myrmecophagidæ), are widely separated in structure from any Old World
animals. Lastly, we have the opossums (Didelphyidæ), a family of
marsupials, but having no close affinity to any of the numerous Australian
forms of that order. We have already arrived at the conclusion that the
presence of marsupials in South America is not due to any direct
transference from Australia, but that their introduction is comparatively
recent, and that they came from the Old World by way of North America (vol.
i., p. 155). But the numerous and deep-seated peculiarities of many other
of its mammalia, would indicate a very remote origin; and a long-continued
isolation of South America from the rest of the world is required, in order
to account for the preservation and development of so many distinct groups
of comparatively low-type quadrupeds.
_Distinctive Characters of Neotropical Birds._--The birds which are
especially characteristic of this region, present similar distinctive
features. In the enormous group of Passerine {8}birds which, though
comprising nearly three-fourths of the entire class, yet presents hardly
any well-marked differences of structure by which it can be subdivided--the
families confined to America are, for the most part, more closely related
to each other than to the Old World groups. The ten families forming the
group of "Formicaroid Passeres," in our arrangement (vol. i., p. 94), are
characterised by the absence of singing muscles in the larynx, and also by
an unusual development of the first primary quill; and seven of this series
of families (which are considered to be less perfectly developed than the
great mass of Old World passeres) are exclusively American, the three
belonging to the Eastern hemisphere being of small extent. Another group of
ten families--our "Tanagroid Passeres," are characterised by the abortion
or very rudimentary condition of the first quill; and of these, five are
exclusively American, and have numerous genera and species, while only two
are non-American, and these are of small extent. On the other hand the
"Turdoid Passeres," consisting of 23 families and comprising all the true
"singing-birds," is poorly represented in America; no family being
exclusively Neotropical, and only three being at all fully represented in
South America, though they comprise the great mass of the Old World
passeres. These peculiarities, which group together whole series of
families of American birds, point to early separation and long isolation,
no less surely than the more remarkable structural divergences presented by
the Neotropical mammalia.
In the Picariæ, we have first, the toucans (Rhamphastidæ); an extraordinary
and beautiful family, whose enormous gaily-coloured bills and long
feathered tongues, separate them widely from all other birds. The Galbulidæ
or jacamars, the motmots (Momotidæ), and the curious little todies (Todidæ)
of the Antilles, are also isolated groups. But most remarkable of all is
the wonderful family of the humming-birds, which ranges over all America
from Tierra del Fuego to Sitka, and from the level plains of the Amazon to
above the snow-line on the Andes; which abounds both in genera, species,
and individuals, and is yet strictly confined to this continent alone! How
vast must have been the time required to develop those beautiful and
{9}highly specialized forms out of some ancestral swift-like type; how
complete and long continued the isolation of their birthplace to have
allowed of their modification and adaptation to such divergent climates and
conditions, yet never to have permitted them to establish themselves in the
other continents. No naturalist can study in detail this single family of
birds, without being profoundly impressed with the vast antiquity of the
South American continent, its long isolation from the rest of the land
surface of the globe, and the persistence through countless ages of all the
conditions requisite for the development and increase of varied forms of
animal life.
Passing on to the parrot tribe, we find the peculiar family of the
Conuridæ, of which the macaws are the highest development, very largely
represented. It is in the gallinaceous birds however that we again meet
with wholly isolated groups. The Cracidæ, including the curassows and
guans, have no immediate relations with any of the Old World families.
Professor Huxley considers them to approach nearest to (though still very
remote from) the Australian megapodes; and here, as in the case of the
marsupials, we probably have divergent modifications of an ancient type
once widely distributed, not a direct communication between the southern
continents. The Tinamidæ or tinamous, point to a still more remote
antiquity, since their nearest allies are believed to be the Struthiones or
ostrich tribe, of which a few representatives are scattered widely over the
globe. The hoazin of Guiana (Opisthocomus) is another isolated form, not
only the type of a family, but perhaps of an extinct order of birds.
Passing on to the waders, we have a number of peculiar family types, all
indicative of antiquity and isolation. The _Cariama_ of the plains of
Brazil, a bird somewhat intermediate between a bustard and a hawk, is one
of these; the elegant _Psophia_ or trumpeter of the Amazonian forests; the
beautiful little sun-bittern of the river banks (_Eurypyga_); and the
horned screamers (_Palamedea_), all form distinct and isolated families of
birds, to which the Old World offers nothing directly comparable.
_Reptiles._--The Neotropical region is very rich in varied forms of reptile
life, and the species are very abundant. It has six {10}altogether peculiar
families, and several others which only range into the Nearctic region, as
well as a very large number of peculiar or characteristic genera. As the
orders of reptiles differ considerably in their distributional features,
they must be considered separately.
The snakes (Ophidia) differ from all other reptiles, and from most other
orders of vertebrates, in the wide average distribution of the families; so
that such an isolated region as the Neotropical possesses no peculiar
family, nor even one confined to the American continent. The families of
most restricted range are--the Scytalidæ, only found elsewhere in the
Philippine islands; the Amblycephalidæ, common to the Oriental and
Neotropical regions; and the Tortricidæ, most abundant in the Oriental
region, but found also in the Austro-Malay islands and Tropical South
America. Sixteen of the families of snakes occur in the region, the
Colubridæ, Amblycephalidæ, and Pythonidæ, being those which are best
represented by peculiar forms. There are 25 peculiar or characteristic
genera, the most important being _Dromicus_ (Colubridæ); _Boa_,
_Epicrates_, and _Ungalia_ (Pythonidæ); _Elaps_ (Elapidæ); and
_Craspedocephalus_ (Crotalidæ).
The lizards (Lacertilia) are generally more restricted in their range;
hence we find that out of 15 families which inhabit the region, 5 are
altogether peculiar, and 4 more extend only to N. America. The peculiar
families are Helodermidæ, Anadiadæ, Chirocolidæ, Iphisiadæ, and
Cercosauridæ; but it must be noted that these all possess but a single
genus each, and only two of them (Chirocolidæ and Cercosauridæ) have more
than a single species. The families which range over both South and North
America are Chirotidæ, Chalcidæ, Teidæ, and Iguanidæ; the first and second
are of small extent, but the other two are very large groups, the Teidæ
possessing 12 genera and near 80 species; the Iguanidæ 40 genera and near
150 species; the greater part of which are Neotropical. There are more than
50 peculiar or highly characteristic genera of lizards, about 40 of which
belong to the Teidæ and Iguanidæ, which thus especially characterize the
region. The most important and characteristic genera are the following;
_Ameiva_ (Teidæ); _Gymnopthalmus_ (Gymnopthalmidæ); {11}_Celestus_ and
_Diploglossus_ (Scincidæ); _Sphærodactylus_ (Geckotidæ); _Liocephalus_,
_Liolæmus_, _Proctotretus_, and many smaller genera (Iguanidæ). The three
extensive Old World families Varanidæ, Lacertidæ, and Agamidæ, are absent
from the entire American continent.
In the order Crocodilia, America has the peculiar family of the alligators
(Alligatoridæ), as well as several species of true crocodiles
(Crocodilidæ). The Chelonia (tortoises) are represented by the families
Testudinidæ and Chelydidæ, both of wide range; but there are six peculiar
genera,--_Dermatemys_ and _Staurotypus_ belonging to the former
family,--_Peltocephalus_, _Podocnemis_, _Hydromedusa_, and _Chelys_, to the
latter. Some of the Amazon river-turtles of the genus _Podocnemys_ rival in
size the largest species of true marine turtles (Cheloniidæ), and are
equally good for food.
_Amphibia._--The Neotropical region possesses representatives of sixteen
families of Amphibia of which four are peculiar; all belonging to Anoura or
tail-less Batrachians. The Cæciliadæ or snake-like amphibia, are
represented by two peculiar genera, _Siphonopsis_ and _Rhinatrema_. Tailed
Batrachians are almost unknown, only a few species of _Spelerpes_
(Salamandridæ) entering Central America, and one extending as far south as
the Andes of Bogota in South America. Tail-less Batrachians on the other
hand, are abundant; there being 14 families represented, of which
4,--Rhinophryndæ, Hylaplesidæ, Plectromantidæ, and Pipidæ are peculiar.
None of these families contain more than a single genus, and only the
second more than a single species; so that it is not these which give a
character to the South American Amphibia-fauna. The most important and best
represented families are, Ranidæ (true frogs), with eleven genera and more
than 50 species; Polypedatidæ (tree-frogs) with seven genera and about 40
species; Hylidæ (tree-frogs) with eight genera and nearly 30 species;
Engystomidæ (toads) (5 genera), Bombinatoridæ (frogs), (4 genera),
Phryniscidæ and Bufonidæ (toads), (each with 2 genera), are also fairly
represented. All these families are widely distributed, but the Neotropical
genera are, in almost every case, peculiar.
{12}_Fresh-water fishes._--The great rivers of Tropical America abound in
fish of many strange forms and peculiar types. Three families, and three
sub-family groups are peculiar, while the number of peculiar genera is
about 120. The peculiar families are Polycentridæ, with two genera;
Gymnotidæ, a family which includes the electric eels, (5 genera); and
Trygonidæ, the rays, which are everywhere marine except in the great rivers
of South America, where many species are found, belonging to two genera. Of
the extensive family Siluridæ, three sub-families Siluridæ anomalopteræ, S.
olisthopteræ, and S. branchiolæ, are confined to this region. The larger
and more important of the peculiar genera are the following: _Percilia_,
inhabiting Chilian and _Percichthys_ South Temperate rivers, belong to the
Perch family (Percidæ); _Acharnes_, found only in Guiana, belongs to the
Nandidæ, a family of wide range in the tropics; the Chromidæ, a family of
exclusively fresh-water fishes found in the tropics of the Ethiopian,
Oriental and Neotropical regions, are here represented by 15 genera, the
more important being _Acara_ (17 sp.), _Heros_ (26 sp.), _Crenicichla_ (9
sp.), _Satanoperca_ (7 sp.). Many of these fishes are beautifully marked
and coloured. The Siluridæ proteropteræ are represented by 14 genera, of
which _Pimelodus_ (42 sp.), and _Platystoma_ (11 sp.), are the most
important; the Siluridæ stenobranchiæ by 11 genera, the chief being _Doras_
(13 sp.), _Auchenipterus_ (9 sp.), and _Oxydoras_ (7 sp.). The Siluridæ
proteropodes are represented by 16 genera, many of them being among the
most singular of fresh-water fishes, clothed in coats of mail, and armed
with hooks and serrated spines. The following are the most
important,--_Chætostomus_ (25 sp.), _Loricaria_ (17 sp.), _Plecostonus_ (15
sp.) and _Callichthys_ (11 sp.). The Characinidæ are divided between
Tropical America and Tropical Africa, the former possessing about 40 genera
and 200 species. The Haplochitonidæ are confined to South America and
Australia; the American genus being _Haplochiton_. The Cyprinodontidæ are
represented by 18 genera, the most important being, _Pæcilia_ (16 sp.),
_Girardinus_ (10 sp.), and _Gambusia_ (8 sp.) The Osteoglossidæ, found in
Australian and African rivers, are represented in South America by the
peculiar _Arapaima_, the "pirarucu" of the {13}Amazon. The ancient
Sirenoidei, also found in Australia and Africa, have the _Lepidosiren_ as
their American representative. Lastly, _Ellipisurus_ is a genus of rays
peculiar to the fresh waters of South America. We may expect these numbers
to be largely increased and many new genera to be added, when the extensive
collections made by Agassiz in Brazil are described.
_Summary of Neotropical Vertebrates._--Summarizing the preceding facts, we
find that the Neotropical region possesses no less than 45 families and
more than 900 genera of Vertebrata which are altogether peculiar to it;
while it has representatives of 168 families out of a total of 330, showing
that 162 families are altogether absent. It has also representatives of 131
genera of Mammalia of which 103 are peculiar to it, a proportion of 4/5;
while of 683 genera of land-birds no less than 576 are peculiar, being
almost exactly 5/6 of the whole. These numbers and proportions are far
higher than in the case of any other region.
_Insects._
The Neotropical region is so excessively rich in insect life, it so abounds
in peculiar groups, in forms of exquisite beauty, and in an endless
profusion of species, that no adequate idea of this branch of its fauna can
be conveyed by the mere enumeration of peculiar and characteristic groups,
to which we are here compelled to limit ourselves. Our facts and figures
will, however, furnish data for comparison; and will thus enable those who
have some knowledge of the entomology of any other country, to form a
better notion of the vast wealth of insect life in this region, than a more
general and picturesque description could afford them.
_Lepidoptera._--The Butterflies of South America surpass those of all other
regions in numbers, variety and beauty; and we find here, not only more
peculiar genera and families than elsewhere, but, what is very remarkable,
a fuller representation of the whole series of families. Out of the 16
families of butterflies in all parts of the world, 13 are found here, and 3
of these are wholly peculiar--Brassolidæ, Heliconidæ, and Eurygonidæ, with
a fourth, Erycinidæ, which only extends into the Nearctic {14}region; so
that there are 4 families peculiar to America. These four families comprise
68 genera and more than 800 species; alone constituting a very important
feature in the entomology of the region. But in almost all the other
families there are numbers of peculiar genera, amounting in all to about
200, or not far short of half the total number of genera in the
world--(431). We must briefly notice some of the peculiarities of the
several families, as represented in this region. The Danaidæ consist of 15
genera, all peculiar, and differing widely from the generally sombre-tinted
forms of the rest of the world. The delicate transparent-winged Ithomias of
which 160 species are described, are the most remarkable. _Melinæa_,
_Napeogenes_, _Ceratina_ and _Dircenna_ are more gaily coloured, and are
among the chief ornaments of the forests. The Satyridæ are represented by
25 peculiar genera, many of great beauty; the most remarkable and elegant
being the genus _Hætera_ and its allies, whose transparent wings are
delicately marked with patches of orange, pink, or violet. The genus
_Morpho_ is perhaps the grandest development of the butterfly type, being
of immense size and adorned with the most brilliant azure tints, which in
some species attain a splendour of metallic lustre unsurpassed in nature.
The Brassolidæ are even larger, but are crepuscular insects, with rich
though sober colouring. The true Heliconii are magnificent insects, most
elegantly marked with brilliant and strongly contrasted tints. The
Nymphalidæ are represented by such a variety of gorgeous insects that it is
difficult to select examples. Prominent are the genera _Catagramma_ and
_Callithea_, whose exquisite colours and symmetrical markings are unique
and indescribable; and these are in some cases rivalled by _Agrias_ and
_Prepona_, which reproduce their style of coloration although not closely
allied to them. The Erycinidæ, consisting of 59 genera and 560 species,
comprise the most varied and beautiful of small butterflies; and it would
be useless to attempt to indicate the unimaginable combinations of form and
colour they present. It must be sufficient to say that nothing elsewhere on
the globe at all resembles them. In Lycænidæ the world-wide genus _Thecla_
is wonderfully developed, and the South {15}American species not only
surpass all others in size and beauty, but some of them are so gorgeous on
the under surface of their wings, as to exceed almost all the combinations
of metallic tints we meet with in nature. The last family, Hesperidæ, is
also wonderfully developed here, the species being excessively numerous,
while some of them redeem the character of this generally sober family, by
their rich and elegant coloration.
In the only other group of Lepidoptera we can here notice, the Sphingina,
the Neotropical region possesses some peculiar forms. The magnificent
diurnal butterfly-like moths, _Urania_, are the most remarkable; and they
are rendered more interesting by the occurrence of a species closely
resembling them in Madagascar. Another family of day-flying moths, the
Castniidæ, is almost equally divided between the Neotropical and Australian
regions, although the genera are more numerous in the latter. The American
Castnias are large, thick-bodied insects, with a coarse scaly surface and
rich dull colours; differing widely from the glossy and gaily coloured
Agaristas, which are typical of the family in the East.
_Coleoptera._--This is so vast a subject that, as in the case of the
regions already treated, we must confine our attention to a few of the more
important and best known families as representatives of the entire order.
Cicindelidæ.--We find here examples of 15 out of the 35 genera of these
insects; and 10 of these genera are peculiar. The most important are
_Oxychila_ (11 sp.), _Hiresia_ (14 sp.), and _Ctenostoma_ (26 sp.).
_Odontochila_ (57 sp.) is the most abundant and characteristic of all, but
is not wholly peculiar, there being a species in the Malay archipelago.
_Tetracha_, another large genus, has species in Australia and a few in
North America and Europe. The small genus _Peridexia_ is divided between
Brazil and Madagascar,--a somewhat similar distribution to that of _Urania_
noticed above. One genus, _Agrius_, is confined to the southern extremity
of the continent.
Carabidæ.--Besides a considerable number of cosmopolitan or wide-spread
genera, this family is represented by more than 100 genera which are
peculiar to the Neotropical region. The {16}most important of these are
_Agra_ (150 sp.), _Ardistonus_ (44 sp.), _Schizogenius_ (25 sp.),
_Pelecium_ (24 sp.), _Calophena_ (22 sp.), _Aspidoglossa_ (21 sp.), and
_Lia_, _Camptodonotus_, _Stenocrepis_, and _Lachnophorus_, with each more
than 12 species. These are all tropical; but there are also a number of
genera (26) peculiar to Chili and South Temperate America. The most
important of these are _Antarctia_ (29 sp,), all except two or three
confined to South Temperate America; _Scelodontis_ (10 sp.), mostly
Chilian; _Feronomorpha_ (6 sp.) all Chilian; and _Tropidopterus_ (4 sp.),
all Chilian. _Helluomorpha_ (18 sp.), is confined to North and South
America; _Galerita_, _Callida_, and _Tetragonoderus_, are large genera
which are chiefly South American but with a few species scattered over the
other tropical regions, _Casnonia_ and _Lebia_ are cosmopolite, but most
abundant in South America. _Pachyteles_ is mostly South American but with a
few species in West Africa; while _Lobodonotus_ has one species in South
America and two in Africa.
Lucanidæ.--The Neotropical species of this family almost all belong to
peculiar genera. Those common to other regions are _Syndesus_, confined to
Tropical South America and Australia, and _Platycerus_ which is Palæarctic
and Nearctic, with one species in Brazil. The most remarkable genus is
undoubtedly _Chiasognathus_, confined to Chili. These are large insects of
metallic green colours, and armed with enormous serrated mandibles. The
allied genera, _Pholidotus_ and _Sphenognathus_, inhabit Tropical South
America. _Streptocerus_ confined to Chili, is interesting, as being allied
to the Australian _Lamprima_. The other genera present no remarkable
features; but _Sclerognathus_ and _Leptinoptera_ are the most extensive.
Cetoniidæ.--These magnificent insects are but poorly represented in
America; the species being mostly of sombre colours. There are 14 genera,
12 of which are peculiar. The most extensive genus is _Gymnetis_, which,
with its allies _Cotinis_ and _Allorhina_, form a group which comprehends
two-thirds of the Neotropical species of the family. The only other genera
of importance are, _Inca_ (7 sp.), remarkable for their large size, and
being the only American group in which horns are developed on the head;
{17}and _Trigonopeltastes_ (6 sp.), allied to the European _Trichius_. The
non-peculiar genera are, _Stethodesma_, of which half the species are
African and half tropical American; and _Euphoria_, confined to America
both North and South.
Buprestidæ.--In this fine group the Neotropical region is tolerably rich,
having examples of 39 genera, 18 of which are peculiar to it. Of these, the
most extensive are _Conognatha_ and _Halecia_, which have a wide range over
most parts of the region; and _Dactylozodes_, confined to the south
temperate zone. Of important genera which range beyond the region,
_Dicerca_ is mainly Nearctic and Palæarctic; _Cinyra_ has a species in
North America and one in Australia; _Curis_ is divided between Chili and
Australia; the Australian genus _Stigmodera_ has a species in Chili;
_Polycesta_ has a species in Madagascar, two in the Mediterranean region,
and a few in North America; _Acherusia_ is divided between Australia and
Brazil; _Ptosima_ has one species in south temperate America, the rest
widely scattered from North America to the Philippines; _Actenodes_ has a
single species in North America and another in West Africa; _Colobogaster_
has two in West Africa, one in Java and one in the Moluccas. The relations
of South America and Australia as indicated by these insects has already
been sufficiently noticed under the latter region.
Longicornia.--The Neotropical Longicorn Coleoptera are overwhelming in
their numbers and variety, their singularity and their beauty. In the
recent Catalogue of Gemminger and Harold, it is credited with 516 genera,
489 of which are peculiar to it; while it has only 5 genera in common
(exclusively) with the Nearctic, and 4 (in the same way) with the
Australian region. Only the more important genera can be here referred to,
under the three great families into which these insects are divided.
The Prionidæ are excessively numerous, being grouped in 64 genera, more
than double the number possessed by any other region; and 61 of these are
peculiar. The three, common to other regions, are, _Parandra_ and
_Mallodon_, which are widely distributed; and _Ergates_, found also in
California and Europe. The most remarkable genera are, the
magnificently-coloured _Psalidognathus_ and _Pyrodes_; the large and
strangely marked {18}_Macrodontia_; and _Titanus_, the largest insect of
the entire family.
Of the Cerambycidæ there are 233 genera, exceeding by one-half, the number
in any other region; and 225 of these are peculiar. Only 2 are common to
the Neotropical and Nearctic regions exclusively, and 3 to the Neotropical
and Australian. The most extensive genera are the elegant _Ibidion_ (80
sp.); the richly-coloured _Chrysoprasis_ (47 sp.); the prettily-marked
_Trachyderes_ (53 sp.); with _Odontocera_ (25 sp.); _Criodon_ (22 sp.); and
a host of others of less extent, but often of surpassing interest and
beauty. The noteworthy genera of wide range are, _Oeme_ and _Cyrtomerus_,
which have each a species in West Africa, and _Hammatocerus_, which has one
in Australia.
The Lamiidæ have 219 genera, and this is the only tropical region in which
they do not exceed the Cerambycidæ. This number is almost exactly the same
as that of the Oriental genera, but here there are more peculiar groups,
203 against 160 in the other region. The most extensive genera are
_Hemilophus_ (80 sp.), _Colobothea_ (70 sp.), _Acanthoderes_ (56 sp.),
_Oncoderes_ (48 sp.), _Lepturgus_ (40 sp.), _Hypsioma_ (32 sp.), and
_Tæniotes_ (20 sp.). _Macropus longimanus_, commonly called the harlequin
beetle, is one of the largest and most singularly-marked insects in the
whole family. _Leptostylus_ has a single species in New Zealand;
_Acanthoderes_ has one species in Europe, W. Africa, and Australia,
respectively; _Spalacopsis_ has a species in W. Africa; _Pachypeza_ is
common to S. America and the Philippines; _Mesosa_ is Oriental and
Palæarctic, but has one species on the Amazon; _Apomecyna_ ranges through
the tropics of the Eastern Hemisphere, but has two species in S. America;
_Acanthocinus_ has one species in Tasmania, and the rest in South America,
North America, and Europe; _Phæa_ is wholly Neotropical, except two species
in the Philippine Islands.
_General Conclusions as to the Neotropical Insect-fauna._--Looking at the
insects of the Neotropical region as a whole, we are struck with the vast
amount of specialty they present; and, considering how many causes there
are which must lead to the dispersal of insects, the number of its groups
which are scattered {19}over the globe is not nearly so great as we might
expect. This points to a long period of isolation, during which the various
forms of life have acted and reacted on each other, leading to such a
complex yet harmoniously-balanced result as to defy the competition of the
chance immigrants that from time to time must have arrived. This is quite
in accordance with the very high antiquity we have shown most insect-forms
to possess; and it is no doubt owing to this antiquity, that such a
complete diversity of _generic_ forms has been here brought about, without
any important deviation from the great _family_ types which prevail over
the rest of the globe.
_Land Shells._--The Neotropical region is probably the richest on the globe
in Terrestrial Mollusca, but this is owing, not to any extreme
productiveness of the equatorial parts of the continent, where almost all
other forms of life are so largely developed, but to the altogether
exceptional riches of the West India Islands. The most recent estimates
show that the Antilles contain more species of land shells than all the
rest of the region, and almost exactly as many as all continental America,
north and south.
Mr. Thomas Bland, who has long studied American land shells, points out a
remarkable difference in the distribution of the Operculated and
Inoperculated groups, the former being predominant on the islands, the
latter on the continent. The Antilles possess over 600 species of
Operculata, to about 150 on the whole American continent, the genera being
as 22 to 14. Of Inoperculata the Antilles have 740, the Continent 1,250,
the genera being 18 and 22. The proportions of the two groups in each
country are, therefore:
West India Islands. American Continent.
Operculata Gen. 22 Sp. 608 14 151
Inoperculata " 18 " 737 22 1251
The extensive family of the Helicidæ is represented by 22 genera, of which
6 are peculiar. _Spiraxis_ is confined to Central America and the Antilles;
_Stenopus_ and _Sagda_ are Antillean only; _Orthalicus_, _Macroceramus_,
and _Bulimulus_ have a wider range, the last two extending into the
southern United {20}States. Important and characteristic genera are,
_Glandina_, in all the tropical parts of the region; _Cylindrella_, in
Central America and the Antilles; _Bulimus_, containing many large and
handsome species in South America; _Stenogyra_, widely spread in the
tropics; and _Streptaxis_, in Tropical South America.
Among the Operculata, the Aciculidæ are mostly Antillean, two genera being
peculiar there, and one, _Truncatella_, of wide distribution, but most
abundant in the West Indian Islands. The Cyclostomidæ are represented by 15
genera, 9 being peculiar to the region, and 5 of these (belonging to the
sub-family Licinidæ) to the Antilles only. Of these peculiar genera
_Cistula_ and _Chondropoma_ are the most important, ranging over all the
tropical parts of the region. Other important genera are _Cyclotus_ and
_Megalomastoma_; while _Cyclophorus_ also occurs all over the region. The
Helicinidæ are mostly Neotropical, six out of the seven genera being found
here, and four are peculiar. _Stoastoma_, is one of the largest genera;
and, with _Trochatella_ and _Alcadia_, is confined to the Antilles, while
the wide-spread _Helicina_ is most abundant there.
The Limacidæ, or Old World slugs, are absent from the region, their place
being taken by the allied family, Oncidiadæ.
_Marine Shells._--We go out of our usual course to say a few words about
the marine shells of this region, because their distribution on the two
sides of the continent is important, as an indication of the former
separation of North and South America, and the connection of the Atlantic
and Pacific Oceans. It was once thought that no species of shells were
common to the two sides of the Central American Isthmus, and Dr. Mörch
still holds that opinion; but Dr. Philip Carpenter, who has paid special
attention to the subject, considers that there are at least 35 species
absolutely identical, while as many others are so close that they may be
only varieties. Nearly 70 others are distinct but representative species.
The genera of marine mollusca are very largely common to the east and west
coasts, more than 40 being so named in the lists published by Mr. Woodward.
The West Indian Islands being a rich shell district, produce a number of
peculiar forms, and the west coast of {21}South America is, to some extent,
peopled by Oriental and Pacific genera of shells. On the west coast there
is hardly any coral, while on the east it is abundant, showing a difference
of physical conditions that must have greatly influenced the development of
mollusca. When these various counteracting influences are taken into
consideration, the identity or close affinity of about 140 species and 40
genera on the two sides of the Isthmus of Panama becomes very important;
and, combined with the fact of 48 species of fish (or 30 per cent. of those
known) being identical on the adjacent coasts of the two oceans (as
determined by Dr. Günther), render it probable that Central America has
been partially submerged up to comparatively recent geological times. Yet
another proof of this former union of two oceans is to be found in the
fossil corals of the Antilles of the Miocene age, which Dr. Duncan finds to
be more allied to existing Pacific forms, than to those of the Atlantic or
even of the Caribbean Sea.
NEOTROPICAL SUB-REGIONS.
In the concluding part of this work devoted to geographical zoology, the
sub-regions are arranged in the order best adapted to exhibit them in a
tabular form, and to show the affinities of the several regions; but for
our present purpose it will be best to take first in order that which is
the most important and most extensive, and which exhibits all the peculiar
characteristics of the region in their fullest development. We begin
therefore with our second division.
_II. Tropical South-America, or the Brazilian Sub-region._
This extensive district may be defined as consisting of all the tropical
forest-region of South America, including all the open plains and pasture
lands, surrounded by, or intimately associated with, the forests. Its
central mass consists of the great forest-plain of the Amazons, extending
from Paranaiba on the north coast of Brazil (long. 42° W.) to Zamora, in
the province of Loja (lat. 4° S., long. 79° W.), high up in the Andes, on
the west;--a distance in a straight line of more than 2,500 English miles,
{22}along the whole of which there is (almost certainly) one continuous
virgin forest. Its greatest extent from north to south, is from the mouths
of the Orinooko to the eastern slopes of the Andes near La Paz in Bolivia
and a little north of Sta. Cruz de la Sierra (lat. 18° S.), a distance of
about 1,900 miles. Within this area of continuous forests, are included
some open "campos," or patches of pasture lands, the most important
being,--the Campos of the Upper Rio Branco on the northern boundary of
Brazil; a tract in the interior of British Guiana; and another on the
northern bank of the Amazon near its mouth, and extending some little
distance on its south bank at Santarem. On the northern bank of the
Orinooko are the Llanos, or flat open plains, partly flooded in the rainy
season; but much of the interior of Venezuela appears to be forest country.
The forest again prevails from Panama to Maracaybo, and southwards in the
Magdalena valley; and on all the western side of the Andes to about 100
miles south of Guayaquil. On the N.E. coast of Brazil is a tract of open
country, in some parts of which (as near Ceara) rain does not fall for
years together; but south of Cape St. Roque the coast-forests of Brazil
commence, extending to lat. 30° S., clothing all the valleys and hill sides
as far inland as the higher mountain ranges, and even penetrating up the
great valleys far into the interior. To the south-west the forest country
reappears in Paraguay, and extends in patches and partially wooded country,
till it almost reaches the southern extension of the Amazonian forests. The
interior of Brazil is thus in the position of a great island-plateau,
rising out of, and surrounded by, a lowland region of ever-verdant forest.
The Brazilian sub-region comprises all this forest-country and its included
open tracts, and so far beyond it as there exists sufficient woody
vegetation to support its peculiar forms of life. It thus extends
considerably beyond the tropic in Paraguay and south Brazil; while the
great desert of Chaco, extending from 25° to 30° S., lat. between the
Parana and the Andes, as well as the high plateaus of the Andean range,
with the strip of sandy desert on the Pacific coast as far as to about 5°
of south latitude, belong to south temperate America, or the sub-region of
the Andes.
{23}Having already given a sketch, of the zoological features of the
Neotropical region as a whole, the greater part of which will apply to this
sub-region, we must here confine ourselves to an indication of the more
important groups which, on the one hand, are confined to it, and on the
other are absent; together with a notice of its special relations to other
regions.
_Mammalia._--Many of the most remarkable of the American monkeys are
limited to this sub-region; as _Lagothrix_, _Pithecia_, and _Brachyurus_,
limited to the great Amazonian forests; _Eriodes_ to south-east Brazil; and
_Callithrix_ to tropical South America. All the marmosets (Hapalidæ) are
also confined to this sub-region, one only being found at Panama, and
perhaps extending a little beyond it. Among other peculiar forms, are 8
genera of bats; 3 peculiar forms of wild dog; _Pteronura_, a genus of
otters; _Inia_, a peculiar form of dolphin inhabiting the upper waters of
the Amazon; tapirs of the genus _Tapirus_ (a distinct genus being found
north of Panama); 4 genera of Muridæ; _Ctenomys_, a genus of Octodontidæ;
the whole family of Echimyidæ, or spiny rats, (as far as the American
continent is concerned) consisting of 8 genera and 28 species; _Chætomys_,
a genus of Cercolabidæ; the capybara (_Hydrochoerus_) the largest known
rodent, belonging to the Caviidæ; the larger ant-eaters (_Myrmecophaga_);
sloths of the genus _Bradypus_; 2 genera of armadillos (Dasypodidæ); and
two peculiar forms of the opossum family (Didelphyidæ). No group that is
typically Neotropical is absent from this sub-region, except such as are
peculiar to other single sub-regions and which will be noticed accordingly.
The occurrence of a solitary species of hare (_Lepus braziliensis_) in
central Brazil and the Andes, is remarkable, as it is cut off from all its
allies, the genus not being known to occur elsewhere on the continent
further south than Costa Rica. The only important external relation
indicated by the Mammalia of this sub-region is towards the Ethiopian
region, 2 genera of Echimyidæ, _Aulacodes_ and _Petromys_, occurring in
South and South-east Africa.
_Plate IV. Characteristic Neotropical Mammalia._--Our illustration
represents a mountainous forest in Brazil, the part of South America where
the Neotropical Mammalia are perhaps best {24}developed. The central and
most conspicuous figure is the collared ant-eater, (_Tamandua
tetradactyla_), one of the handsomest of the family, in its conspicuous
livery of black and white. To the left are a pair of sloths (_Arctopithecus
flaccidus_) showing the curious black spot on the back with which many of
the species are marked, and which looks like a hole in the trunk of a tree;
but this mark seems to be only found on the male animal. The fur of many of
the sloths has a greenish tinge, and Dr. Seemann remarked its resemblance
to the _Tillandsia usneoides_, or "vegetable horsehair," which clothes many
of the trees in Central America; and this probably conceals them from their
enemies, the harpy-eagles. On the right are a pair of opossums (_Didelphys
azaræ_), one of them swinging by its prehensile tail. Overhead in the
foreground are a group of howling monkeys (_Mycetes ursinus_) the largest
of the American Quadrumana, and the noisiest of monkeys. The large hollow
vessel into which the hyoid bone is transformed, and which assists in
producing their tremendous howling, is altogether unique in the animal
kingdom. Below them, in the distance, are a group of Sapajou monkeys
(_Cebus_ sp.); while gaudy screaming macaws complete the picture of
Brazilian forest life.
_Birds._--A very large number of genera of birds, and some entire families,
are confined to this sub-region, as will be seen by looking over the list
of genera at the end of this chapter. We can here only notice the more
important, and summarize the results. More than 120 genera of Passeres are
thus limited, belonging to the following 12 families: Sylviidæ (1),
Troglodytidæ (2), Coerebidæ (4), Tanagridæ (26), Fringillidæ (8), Icteridæ
(5), Pteroptochidæ (3), Dendrocolaptidæ (12), Formicariidæ (16), Tyrannidæ
(22), Cotingidæ (16), Pipridæ (10). Of the Picariæ there are 76 peculiar
genera belonging to 9 families, viz., Picidæ (2), Rhamphastidæ (1),
Cuculidæ (1), Bucconidæ (2), Galbulidæ (5), Momotidæ (2), Podargidæ (1),
Caprimalgidæ (4), Trochilidæ (58). There are 3 peculiar genera of Psittaci,
8 of Gallinæ, the only genus of Opisthocomidæ, 3 of Accipitres, 1 of
Rallidæ, _Psophia_ and _Eurypyga_ types of distinct families, and 1 genus
of Ardeidæ, Palamedeidæ, and Anatidæ respectively. The preceding
enumeration shows how very rich this sub-region is in peculiar types of all
the most characteristic American families, such as the Tanagridæ,
Tyrannidæ, Cotingidæ, Formicariidæ, Trochilidæ, and Galbulidæ. A
considerable proportion of the genera of the Chilian and Mexican
sub-regions also occur here, so that out of about 680 genera of Neotropical
land-birds more than 500 are represented in this sub-region.
Plate XIV.
[Illustration]
A BRAZILIAN FOREST, WITH CHARACTERISTIC MAMMALIA.
{25}Without entering minutely into the distribution of species it is
difficult to sub-divide this extensive territory with any satisfactory
result.[1] The upland tract between the Amazon and Orinooko, which may be
termed Guiana, was evidently once an island, yet it possesses few marked
distinctive features. Brazil, which must have formed another great island,
has more speciality, but the intermediate Amazonian forests form a perfect
transition between them. The northern portion of the continent west of the
Orinooko has more character; and there are indications that this has
received many forms from Central and North America, and thus blended two
faunas once more distinct than they are now. The family of wood-warblers
(Mniotiltidæ) seems to have belonged to this more northern fauna; for out
of 18 genera only 5 extend south of the equator, while 6 range from Mexico
or the Antilles into Columbia, some of these being only winter immigrants
and no genus being exclusively South American. The eastern slopes of the
Andes constitute, however, the richest and best marked province of this
sub-region. At least 12 genera of tanagers (Tanagridæ) are found here only,
with an immense number of Fringillidæ,--the former confined to the forests;
the latter ranging to the upland plains. The ant-thrushes (Formicariidæ) on
the other hand seem more abundant in the lowlands, many genera being
peculiar to the Amazonian forests. The superb chatterers (Cotingidæ) also
seem to have their head-quarters in the forests of Brazil and Guiana, and
to have thence spread {26}into the Amazonian valley. Guiana still boasts
such remarkable forms as the cardinal chatterer (_Phoenicocercus_), the
military chatterer (_Hæmatoderus_), as well as _Querula_, _Gymnoderus_, and
_Gymnocephalus_; but the first three pass to the south side of the Lower
Amazon. Here also belong the cock of the rock (_Rupicola_), which ranges
from Guiana to the Andes, and the marvellous umbrella-birds of the Rio
Nigro and Upper Amazon (_Cephalopterus_), which extends across the
Ecuadorean Andes and into Costa Rica. Brazil has _Ptilochloris_,
_Casiornis_, _Tijuca_, _Phibalura_, and _Calyptura_; while not a single
genus of this family, except perhaps _Heliochæra_, is confined to the
extensive range of the Andes. Almost the same phenomena are presented by
the allied Pipridæ or manakins, the greater part of the genera and species
occurring in Eastern South America, that is in Brazil, Guiana, and the
surrounding lowlands rather than in the Andean valleys. The same may be
said of the jacamars (Galbulidæ) and puff-birds (Bucconidæ); but the
humming-birds (Trochilidæ) have their greatest development in the Andean
district. Brazil and Guiana have each a peculiar genus of parrots; Guiana
has three peculiar genera of Cracidæ, while the Andes north of the equator
have two. The Tinamidæ on the other hand have their metropolis in Brazil,
which has two or three peculiar genera, while two others seem confined to
the Andes south of the equator. The elegant trumpeters (Psophiidæ) are
almost restricted to the Amazonian valley.
Somewhat similar facts occur among the Mammalia. At least 3 genera of
monkeys are confined to the great lowland equatorial forests and 1 to
Brazil; _Icticyon_ (Canidæ) and _Pteronura_ (Mustelidæ) belong to Guiana
and Brazil; and most of the Echimyidæ are found in the same districts. The
sloths, ant-eaters, and armadillos all seem more characteristic of the
eastern districts than of the Andean; while the opossums are perhaps
equally plentiful in the Andes.
The preceding facts of distribution lead us to conclude that the highlands
of Brazil and of Guiana represent very ancient lands, dating back to a
period long anterior to the elevation of the Andean range (which is by no
means of great geological {27}antiquity) and perhaps even to the elevation
of the continuous land which forms the base of the mountains. It was, no
doubt, during their slow elevation and the consequent loosening of the
surface, that the vast masses of debris were carried down which filled up
the sea separating the Andean chain from the great islands of Brazil and
Guiana, and formed that enormous extent of fertile lowland forest, which
has created a great continent; given space for the free interaction of the
distinct faunas which here met together, and thus greatly assisted in the
marvellous development of animal and vegetable life, which no other
continent can match. But this development, and the fusion of the various
faunas into one homogeneous assemblage must have been a work of time; and
it is probable that most of the existing continent was dry land before the
Andes had acquired their present altitude. The blending of the originally
distinct sub-faunas has been no doubt assisted by elevations and
depressions of the land or of the ocean, which have alternately diminished
and increased the land-area. This would lead to a crowding together at one
time, and a dispersion at others, which would evidently afford opportunity
for many previously restricted forms to enter fresh areas and become
adapted to new modes of life.
From the preceding sketch it will appear, that the great sub-region of
Tropical South America as here defined, is really formed of three
originally distinct lands, fused together by the vast lowland Amazonian
forests. In the class of birds sufficient materials exist for separating
these districts; and that of the Andes contains a larger series of peculiar
genera than either of the other sub-regions here adopted. But there are
many objections to making such a sub-division here. It is absolutely
impossible to define even approximate limits to these divisions--to say for
example where the "Andes" ends and where "Brazil" or "Amazonia" or "Guiana"
begins; and the unknown border lands separating these are so vast, that
many groups, now apparently limited in their distribution, may prove to
have a very much wider range. In mammalia, reptiles, and insects, it is
even more difficult to maintain such divisions, so that on the whole it
seems better to treat the entire area as one sub-region, {28}although
recognizing the fact of its zoological and geographical diversity, as well
as its vast superiority over every other sub-region in the number and
variety of its animal forms.
The reptiles, fishes, mollusca, and insects of this sub-region have been
sufficiently discussed in treating of the entire region, as by far the
larger proportion of them, except in the case of land-shells, are found
here.
_Plate XV. Characteristic Neotropical Birds._--To illustrate the
ornithology of South America we place our scene on one of the tributaries
of the Upper Amazon, a district where this class of animals is the most
prominent zoological feature, and where a number of the most remarkable and
interesting birds are to be found. On the left we have the umbrella-bird
(_Cephalopterus ornatus_), so called from its wonderful crest, which, when
expanded, completely overshadows its head like an umbrella. It is also
adorned with a long tassel of plumes hanging from its breast, which is
formed by a slender fleshy tube clothed with broad feathers. The bird is as
large as a crow, of a glossy blue-black colour, and belongs to the same
family as the exquisitely tinted blue-and-purple chatterers. Flying towards
us are a pair of curl-crested toucans (_Pteroglossus beauharnaisii_),
distinguished among all other toucans by a crest composed of small black
and shining barbless plumes, resembling curled whalebone. The general
plumage is green above, yellow and red beneath, like many of its allies. To
the right are two of the exquisite little whiskered hummers, or
"frill-necked coquettes," as they are called by Mr. Gould, (_Lophornis
gouldi_). These diminutive birds are adorned with green-tipped plumes
springing from each side of the throat, as well as with beautiful crests,
and are among the most elegant of the great American family of
humming-birds, now numbering about 400 known species. Overhead are perched
a pair of curassows (_Crax globulosa_), which represent in America the
pheasants of the Old World. There are about a dozen species of these fine
birds, most of which are adorned with handsome curled crests. That figured,
is distinguished by the yellow caruncular swellings at the base of the
bill. The tall crane-like bird near the water is one of the trumpeters,
(_Psophia leucoptera_), elegant birds with silky plumage peculiar to the
Amazon valley. They are often kept in houses, where they get very tame and
affectionate; and they are useful in catching flies and other house
insects, which they do with great perseverance and dexterity.
Plate XV.
[Illustration]
A FOREST SCENE ON THE UPPER AMAZON, WITH SOME CHARACTERISTIC BIRDS.
{29}_Islands of Tropical South America._
These are few in number, and, with one exception, not of much interest.
Such islands as Trinidad and Sta. Catherina form parts of South America,
and have no peculiar groups of animals. The small islands of Fernando
Noronha, Trinidad, and Martin Vaz, off the coast of Brazil, are the only
Atlantic islands somewhat remote from land; while the Galapagos Archipelago
in the Pacific is the only group whose productions have been carefully
examined, or which present features of special interest.
_Galapagos Islands._--These are situated on the equator, about 500 miles
from the coast of Ecuador. They consist of the large Albemarle island, 70
miles long; four much smaller (18 to 25 miles long), named Narborough,
James, Indefatigable, and Chatham Islands; four smaller still (9 to 12
miles long), named Abingdon, Bindloes, Hood's, and Charles Islands. All are
volcanic, and consist of fields of black basaltic lava, with great numbers
of extinct craters, a few which are still active. The islands vary in
height from 1,700 to 5,000 feet, and they all rise sufficiently high to
enter the region of moist currents of air, so that while the lower parts
are parched and excessively sterile, above 800 or 1,000 feet there is a
belt of comparatively green and fertile country.
These islands are known to support 58 species of Vertebrates,--1 quadruped,
52 birds and 5 reptiles, the greater part of which are found nowhere else,
while a considerable number belong to peculiar and very remarkable genera.
We must therefore notice them in some detail.
_Mammalia._--This class is represented by a mouse belonging to the American
genus _Hesperomys_, but slightly different from any found on the continent.
A true rat (_Mus_), slightly differing from any European species, also
occurs; and as there can be little doubt that this is an escape from a
ship, somewhat {30}changed under its new conditions of life (the genus
_Mus_ not being indigenous to the American continent), it is not
improbable, as Mr. Darwin remarks, that the American mouse may also have
been imported by man, and have become similarly changed.
_Birds._[2]--Recent researches in the islands have increased the number of
land-birds to thirty-two, and of wading and aquatic birds to twenty-three.
All the land birds but two or three are peculiar to the islands, and
eighteen, or considerably more than half, belong to peculiar genera. Of the
waders 4 are peculiar, and of the swimmers 2. These are a rail (_Porzana
spilonota_); two herons (_Butorides plumbea_ and _Nycticorax pauper_); a
flamingo (_Phoenicopterus glyphorhynchus_); while the new aquatics are a
gull (_Larus fuliginosus)_, and a penguin (_Spheniscus mendiculus_).
The land-birds are much more interesting. All except the birds of prey
belong to American genera which abound on the opposite coast or on that of
Chili a little further south, or to peculiar genera allied to South
American forms. The only _species_ not peculiar are, _Dolichonyx
oryzivorus_, a bird of very wide range in America and of migratory habits,
which often visits the Bermudas 600 miles from North America,--and _Asio
accipitrinus_, an owl which is found almost all over the world. The only
genera not exclusively American are _Buteo_ and _Strix_, of each of which a
peculiar species occurs in the Galapagos, although very closely allied to
South American species. There remain 10 genera, all either American or
peculiar to the Galapagos; and on these we will remark in systematic order.
1. _Mimus_, the group of American mocking-thrushes, is represented by three
distinct and well-marked species. 2. _Dendroeca_, an extensive and
wide-spread genus of the wood-warblers (Mniotiltidæ), is represented by one
species, which ranges over the greater part of the archipelago. The genus
is especially abundant in Mexico, the Antilles, and the northern parts of
{31}tropical America, only one species extending south as far as Chili. 3.
_Certhidea_, a peculiar genus originally classed among the finches, but
which Mr. Sclater, who has made South American birds his special study,
considers to belong to the _Coerebidæ_, or sugar-birds, a family which is
wholly tropical. Two species of this genus inhabit separate islands. 4.
_Progne_, the American martins (Hirundinidæ), is represented by a peculiar
species. 5. _Geospiza_, a peculiar genus of finches, of which no less than
eight species occur in the archipelago, but not more than four in any one
island. 6. _Camarhynchus_ (6 sp.) and 7. _Cactornis_ (4 sp.) are two other
peculiar genera of finches; some of the species of which are confined to
single islands, while others inhabit several. 8. _Pyrocephalus_, a genus of
the American family of tyrant-flycatchers (Tyrannidæ), has one peculiar
species closely allied to _T. rubineus_, which has a wide range in South
America. 9. _Myiarchus_, another genus of the same family which does not
range further south than western Ecuador, has also a representative species
found in several of the islands. 10. _Zenaida_, an American genus of
pigeons, has a species in James Island and probably in some of the others,
closely allied to a species from the west coast of America.
It has been already stated that some of the islands possess peculiar
species of birds distinct from the allied forms in other islands, but
unfortunately our knowledge of the different islands is so unequal and of
some so imperfect, that we can form no useful generalizations as to the
distribution of birds among the islands themselves. The largest island is
the least known; only one bird being recorded from it, one of the
mocking-thrushes found nowhere else. Combining the observations of Mr.
Darwin with those of Dr. Habel and Prof. Sundevall, we have species
recorded as occurring in seven of the islands. Albemarle island has but one
definitely known species; Chatham and Bindloe islands have 11 each;
Abingdon and Charles islands 12 each; Indefatigable island and James island
have each 18 species. This shows that birds are very fairly distributed
over all the islands, one of the smallest and most remote (Abingdon)
furnishing as many as the much larger Chatham Island, which is also the
nearest {32}to the mainland. Taking the six islands which seem tolerably
explored, we find that two of the species (_Dendroeca aureola_ and
_Geospiza fortis_) occur in all of them; two others (_Geospiza strenua_ and
_Myiarchus magnirostris_) in five; four (_Mimus melanotis_, _Geospiza
fuliginosa_, _G. parvula_, and _Camarhynchus prosthemelas_) in four
islands; five (_Certhidea olivacea_, _Cactornis scandens_, _Pyrocephalus
nanus_), and two of the birds of prey, in three islands; nine (_Certhidea
fusca_, _Progne concolor_, _Geospiza nebulosa_, _G. magnirostris_,
_Camarhynchus psittaculus_, _C. variegatus_, _C. habeli_ and _Asio
accipitrinus_) in two islands; while the remaining ten species are confined
to one island each. These peculiar species are distributed among the
islands as follows. James, Charles and Abingdon islands, have 2 each;
Bindloes, Chatham, and Indefatigable, 1 each. The amount of speciality of
James Island is perhaps only apparent, owing to our ignorance of the fauna
of the adjacent large Albemarle island; the most remote islands north and
south, Abingdon and Charles, have no doubt in reality most peculiar
species, as they appear to have. The scarcity of peculiar species in
Chatham Island is remarkable, it being large, very isolated, and the
nearest to the mainland. There is still room for exploration in these
islands, especially in Albemarle, Narborough, and Hood's islands of which
we know nothing.
_Reptiles._--The few reptiles found in these islands are very interesting.
There are two snakes, a species of the American genus _Herpetodryas_, and
another which was at first thought to be a Chilian species (_Psammophis
Temminckii_), but which is now considered to be distinct. Of lizards there
are four at least, belonging to as many genera. One is a species of
_Phyllodactylus_, a wide-spread genus of Geckotidæ; the rest belong to the
American family of the Iguanas, one being a species of the Neotropical
genus _Leiocephalus_, the other two very remarkable forms, _Trachycephalus_
and _Oreocephalus_ (formerly united in the genus _Amblyrhynchus_). The
first is a land, the second a marine, lizard; both are of large size and
very abundant on all the islands; and they are quite distinct from any of
the very numerous genera of Iguanidæ, spread all over the American
continent. The last {33}reptile is a land tortoise (_Testudo nigra_) of
immense size, and also abundant in all the islands. Its nearest ally is the
equally large species of the Mascarene Islands; an unusual development due,
in both cases, to the absence of enemies permitting these slow but
continually growing animals to attain an immense age. It is believed that
each island has a distinct variety or species of tortoise.
_Insects_.--Almost the only insects known from these islands are some
Coleoptera, chiefly collected by Mr. Darwin. They consist of a few peculiar
species of American or wide-ranging genera, the most important being, a
_Calosoma_, _Poecilus_, _Solenophorus_, and _Notaphus_, among the Carabidæ;
an _Oryctes_ among the Lamellicornes; two new genera of obscure Heteromera;
two Curculionidæ of wide-spread genera; a Longicorn of the South American
genus _Eburia_; and two small Phytophaga,--a set of species highly
suggestive of accidental immigrations at rare and distant intervals.
_Land-Shells._--These consist of small and obscure species, forming two
peculiar sub-genera of _Bulimulus_, a genus greatly developed on the whole
West coast of America; and a single species of _Buliminus_, a genus which
ranges over all the world except America. As in the case of the birds, most
of the islands have two or three peculiar species.
_General Conclusions._--These islands are wholly volcanic and surrounded by
very deep sea; and Mr. Darwin is of opinion, not only that the islands have
never been more nearly connected with the mainland than at present, but
that they have never been connected among themselves. They are situated on
the Equator, in a sea where gales and storms are almost unknown. The main
currents are from the south-west, an extension of the Peruvian drift along
the west coast of South America. From their great extent, and their
volcanoes being now almost extinct, we may assume that they are of
considerable antiquity. These facts exactly harmonize with the theory, that
they have been peopled by rare accidental immigrations at very remote
intervals. The only peculiar _genera_ consist of birds and lizards, which
must therefore have been the earliest {34}immigrants. We know that small
Passerine birds annually reach the Bermudas from America, and the Azores
from Europe, the former travelling over 600, the latter over 1000 miles of
ocean. These groups of islands are both situated in stormy seas, and the
immigrants are so numerous that hardly any specific change in the resident
birds has taken place. The Galapagos receive no such annual visitants;
hence, when by some rare accident a few individuals of a species did
arrive, they remained isolated, probably for thousands of generations, and
became gradually modified through natural selection under completely new
conditions of existence. Less rare and violent storms would suffice to
carry some of these to other islands, and thus the archipelago would in
time become stocked. It would appear probable, that those which have
undergone most change were the earliest to arrive; so that we might look
upon the three peculiar genera of finches, and _Certhidea_, the peculiar
form of Coerebidæ, as among the most ancient inhabitants of the islands,
since they have become so modified as to have apparently no near allies on
the mainland. But other birds may have arrived nearly at the same time, and
yet not have been much changed. A species of very wide range, already
adapted to live under very varied conditions and to compete with varied
forms of life, might not need to become modified so much as a bird of more
restricted range, and more specialized constitution. And if, before any
considerable change had been effected, a second immigration of the same
species occurred, crossing the breed would tend to bring back the original
type of form. While, therefore, we may be sure that birds like the finches,
which are profoundly modified and adapted to the special conditions of the
climate and vegetation, are among the most ancient of the colonists; we
cannot be sure that the less modified form of tyrant-flycatcher or
mocking-thrush, or even the unchanged but cosmopolitan owl, were not of
coeval date; since even if the parent form on the continent has been
changed, successive immigrations may have communicated the same change to
the colonists.
The reptiles are somewhat more difficult to account for. We know, however,
that lizards have some means of dispersal over {35}the sea, because we find
existing species with an enormous range. The ancestors of the
_Amblyrhynchi_ must have come as early, probably, as the earliest birds;
and the same powers of dispersal have spread them over every island. The
two American genera of lizards, and the tortoises, are perhaps later
immigrants. Latest of all were the snakes, which hardly differ from
continental forms; but it is not at all improbable that these latter, as
well as the peculiar American mouse, have been early human importations.
Snakes are continually found on board native canoes whose cabins are
thatched with palm leaves; and a few centuries would probably suffice to
produce some modification of a species completely isolated, under
conditions widely different from those of its native country. Land-shells,
being so few and small, and almost all modifications of one type, are a
clear indication of how rare are the conditions which lead to their
dispersal over a wide extent of ocean; since two or three individuals,
arriving on two or three occasions only during the whole period of the
existence of the islands, would suffice to account for the present fauna.
Insects have arrived much more frequently; and this is in accordance with
their habits, their lower specific gravity, their power of flight, and
their capacity for resisting for some time the effects of salt water.
We learn, then, from the fauna of these islands, some very important facts.
We are taught that tropical land-birds, unless blown out of their usual
course by storms, rarely or never venture out to sea, or if they do so, can
seldom pass safely over a distance of 500 miles. The immigrants to the
Galapagos can hardly have averaged a bird in a thousand years. We learn,
that of all reptiles lizards alone have some tolerably effective mode of
transmission across the sea; and this is probably by means of currents, and
in connection with floating vegetation. Yet their transmission is a far
rarer event than that of land-birds; for, whereas three female immigrants
will account for the lizard population, at least eight or ten ancestors are
required for the birds. Land serpents can pass over still more rarely, as
two such transmissions would have sufficed to stock the islands with their
snakes; and it is not certain that either of these occurred without the aid
of man. {36}It is doubtful whether mammals or batrachians have any means of
passing, independently of man's assistance; the former having but one
doubtfully indigenous representative, the latter none at all. The
remarkable absence of all gay or conspicuous flowers in these tropical
islands, though possessing a zone of fairly luxuriant shrubby vegetation,
and the dependence of this phenomenon on the extreme scarcity of insects,
has been already noticed at Vol. I. p. 461, when treating of a somewhat
similar peculiarity of the New Zealand fauna and flora.
_I. South Temperate America, or the Chilian Sub-region._
This sub-region may be generally defined as the temperate portion of South
America. On the south, it commences with the cold damp forests of Tierra
del Fuego, and their continuation up the west coast to Chiloe and northward
to near Santiago. To the east we have the barren plains of Patagonia,
gradually changing towards the north into the more fertile, but still
treeless, pampas of La Plata. Whether this sub-region should be continued
across the Rio de la Plata into Uruguay and Entre-rios, is somewhat
doubtful. To the west of the Parana it extends northward over the Chaco
desert, till we approach the border of the great forests near St. Cruz de
la Sierra. On the plateau of the Andes, however, it must be continued still
further north, along the "paramos" or alpine pastures, till we reach 5° of
South latitude. Beyond this the Andes are very narrow, having no double
range with an intervening plateau; and although some of the peculiar forms
of the temperate zone pass on to the equator or even beyond it, these are
not sufficiently numerous to warrant our extending the sub-region to
include them. Along with the high Andes it seems necessary to include the
western strip of arid country, which is mostly peopled by forms derived
from Chili and the south temperate regions.
_Mammalia._--This sub-region is well characterised by the possession of an
entire family of mammalia having Neotropical affinities--the Chinchillidæ.
It consists of 3 genera--_Chinchilla_ (2 sp.), inhabiting the Andes of
Chili and Peru as far as 9° south latitude, and at from 8,000 to 12,000
feet altitude; _Lagidium_ (3 sp.), ranging over the Andes of Chili, Peru,
and South Ecuador, {37}from 11,000 to 16,000 feet altitude; and
_Lagostomus_ (1 sp.), the "viscacha," confined to the pampas between the
Uruguay and Rio Negro. Many important genera are also confined to this
sub-region. _Auchenia_ (4 sp.), including the domesticated llamas and
alpacas, the vicugna which inhabits the Andes of Peru and Chili, and the
guanaco which ranges over the plains of Patagonia and Tierra del Fuego.
Although this genus is allied to the Old World camels, it is a very
distinct form, and its introduction from North America, where the family
appear to have originated, may date back to a remote epoch. _Ursus
ornatus_, the "spectacled bear" of the Chilian Andes, is a remarkable form,
supposed to be most allied to the Malay bear, and probably forming a
distinct genus, which has been named _Tremarctos_. Four genera of
Octodontidæ are also peculiar to this sub-region, or almost so;
_Habrocomus_ (1 sp.) is Chilian; _Spalacopus_ (2 sp.) is found in Chili and
on the east side of the southern Andes; _Octodon_ (3 sp.) ranges from Chili
into Peru and Bolivia; _Ctenomys_ (6 sp.) from the Straits of Magellan to
Bolivia, with one species in South Brazil. _Dolichotis_, one of the Cavies,
ranges from Patagonia to Mendoza, and on the east coast to 37½° S.
latitude. _Myopotamus_ (1 sp.), the coypu (Echimyidæ), ranges from 33° to
48° S. latitude on the west side of the Andes, and from the frontiers of
Peru to 42° S. on the east side. _Reithrodon_ and _Acodon_, genera of
Muridæ, are also confined to Temperate South America; _Tolypeutes_ and
_Chlamydophorus_, two genera of armadillos, the latter very peculiar in its
organization and sometimes placed in a distinct family, are found only in
La Plata and the highlands of Bolivia, and so belong to this sub-region.
_Otaria_, one of the "eared seals" (Otariidæ), is confined to the coasts of
this sub-region and the antarctic islands. Deer of American groups extend
as far as Chiloe on the west, and the Straits of Magellan on the east
coast. Mice of the South American genera _Hesperomys_ and _Reithrodon_, are
abundant down to the Straits of Magellan and into Tierra del Fuego, Mr.
Darwin having collected more than 20 distinct species. The following are
the genera of Mammalia which have been observed on the shores of the
Straits of Magellan, those marked * extending into Tierra del Fuego:
{38}*_Pseudalopex_ (two wolf-like foxes), _Felis_ (the puma), _Mephitis_
(skunks), _Cervus_ (deer), *_Auchenia_ (guanaco), *_Ctenomys_ (tucu-tucu),
*_Reithrodon_ and *_Hesperomys_ (American mice).
_Birds._--Three families of Birds are confined to this
sub-region,--Phytotomidæ (1 genus, 3 sp.), inhabiting Chili, La Plata, and
Bolivia; Chionididæ (1 genus, 2 sp.) the "sheath-bills," found only at the
southern extremity of the continent and in Kerguelen's Island, which with
the other antarctic lands perhaps comes best here; Thinocoridæ (2 genera, 6
species) an isolated family of waders, ranging over the whole sub-region
and extending northward to the equatorial Andes. Many genera are also
peculiar: 3 of Fringillidæ, and 1 of Icteridæ; 9 of Dendrocolaptidæ, 6 of
Tyrannidæ, 3 of Trochilidæ, and 4 of Pteroptochidæ,--the last four South
American families. There is also a peculiar genus of parrots
(_Henicognathus_) in Chili; two of pigeons (_Metriopelia_ and _Gymnopelia_)
confined to the Andes and west coast from Peru to Chili; two of Tinamous,
_Tinamotes_ in the Andes, and _Calodromus_ in La Plata; three of
Charadriidæ, _Phægornis_, _Pluvianellus_, and _Oreophilus_; and _Rhea_, the
American ostriches, inhabiting all Patagonia and the pampas. Perhaps the
Cariamidæ have almost as much right here as in the last sub-region,
inhabiting as they do, the "pampas" of La Plata and the upland "campos" of
Brazil; and even among the wide-ranging aquatic birds, we have a peculiar
genus, _Merganetta_, one of the duck family, which is confined to the
temperate plateau of the Andes.
Against this extensive series of characteristic groups, all either of
American type or very distinct forms of Old World families, and therefore
implying great antiquity, we find, in mammalia and birds, very scanty
evidence of that direct affinity with the north temperate zone, on which
some naturalists lay so much stress. We cannot point to a single
terrestrial genus, which is characteristic of the north and reappears in
this south temperate region without also occurring over much of the
intervening land. _Mustela_ seems only to have reached Peru; _Lepus_ is
isolated in Brazil; true _Ursus_ does not pass south of Mexico. In birds,
the northern groups rarely go further south than Mexico or the Columbian
Andes; and the only case of discontinuous {39}distribution we can find
recorded is that of the genus of ducks, _Camptolæmus_, which has a species
on the east side of North America and another in Chili and the Falkland
Islands, but these, Professor Newton assures me, do not properly belong to
the same genus. Out of 30 genera of land-birds collected on the Rio Negro
in Patagonia, by Mr. Hudson, only four extend beyond the American
continent, and the same exclusively American character applies equally to
its southern extremity. No list appears to have been yet published of the
land-birds of the Straits of Magellan and Tierra del Fuego. The following
is compiled from the observations of Mr. Darwin, the recent voyage of
Professor Cunningham, and other sources; and will be useful for comparison.
TURDIDÆ.
1. Turdus falklandicus.
TROGLODYTIDÆ.
2. Troglodytes magellanicus.
FRINGILLIDÆ.
3. Chrysomitris barbata.
*4. Phrygilus gayi.
*5. " aldunatii.
6. " fruticeti.
*7. " xanthogrammus.
8. Zonotrichia pileata.
ICTERIDÆ.
9. Sturnella militaris.
10. Curæus aterrimus.
HIRUNDINIDÆ.
11. Hirundo meyeni.
TYRANNIDÆ.
12. Tænioptera pyrope.
13. Myiotheretes rufiventris.
14. Muscisaxicola mentalis.
15. Centrites niger.
16. Anæretes parulus.
17. Elainea griseogularis.
DENDROCOLAPTIDÆ.
18. Upucerthia dumetoria.
*19. Cinclodes patagonicus.
*20. " fuscus.
*21. Oxyurus spinicauda.
PTEROPTOCHIDÆ.
*22. Scytalopus magellanicus.
PICIDÆ.
*23. Campephilus magellanicus.
24. Picus lignarius.
ALCEDINIDÆ.
25. Ceryle stellata.
TROCHILIDÆ.
26. Eustephanus galeritus.
CONURIDÆ.
27. Conurus patagonus.
VULTURIDÆ.
28. Cathartes aura.
29. Sarcorhamphus gryphus.
FALCONIDÆ.
30. Circus macropterus.
31. Buteo erythronotus.
32. Geranoaëtus melanolencus.
33. Accipiter chilensis.
34. Cerchneis sparverius.
35. Milvago albogularis.
36. Polyborus tharus.
STRIGIDÆ.
37. Asio accipitrinus.
38. Bubo magellanicus.
39. Pholeoptynx cunicularia.
40. Glaucidium nana.
41. Syrnium rufipes.
STRUTHIONIDÆ.
42. Rhea darwinii.
{40}In the above list the species marked * extend to Tierra del Fuego. It
is a remarkable fact that so many of the species belong to genera which are
wholly Neotropical, and that the specially South American families of
Icteridæ, Tyrannidæ, Dendrocolaptidæ, Pteroptochidæ, Trochilidæ, and
Conuridæ, should supply more than one-third of the species; while the
purely South American genus _Phrygilus_, should be represented by four
species, three of which abound in Tierra del Fuego.
_Plate XVI. A Scene in the Andes of Chili, with characteristic
Animals._--The fauna of South Temperate America being most fully developed
in Chili, we place the scene of our illustration in that country. In the
foreground we have a pair of the beautiful little chinchillas (_Chinchilla
lanigera_), belonging to a family of animals peculiar to the sub-region.
There are only two species of this group, both confined to the higher
Andes, at about 8000 feet elevation. Coming round a projecting ridge of the
mountain, are a herd of vicunas (_Auchenia vicugna_), one of that peculiar
form of the camel tribe found in South America and confined to its
temperate and alpine regions. The upper bird is a plant-cutter (_Phytotoma
rara_), of sober plumage but allied to the beautiful chatterers, though
forming a separate family. Below, standing on a rock, is a plover-like
bird, the _Thinocorus orbignianus_, which is considered to belong to a
separate family, though allied to the plovers and sheath-bills. Its habits
are, however, more those of the quails or partridges, living inland in dry
and desert places, and feeding on plants, roots, and insects. Above is a
condor, the most characteristic bird of the high Andes.
_Reptiles and Amphibia._--These groups show, for the most part, similar
modifications of American and Neotropical forms, as those we have seen to
prevail among the birds. Snakes do not seem to go very far south, but
several South American genera of Colubridæ and Dendrophidæ occur in Chili;
while _Enophrys_ is peculiar to La Plata, and _Callorhinus_ to Patagonia,
both belonging to the Colubridæ. The Elapidæ do not extend into the
temperate zone; but _Craspedocephalus_, one of the Crotalidæ, occurs at
Bahia Blanca in Patagonia (Lat. 40° S.)
Plate XVI.
[Illustration]
THE CHILIAN ANDES, WITH CHARACTERISTIC ANIMALS.
{41}Lizards are much more numerous, and there are several peculiar and
interesting forms. Three families are represented; Teidæ by two
genera--_Callopistes_ peculiar to Chili, and _Ameiva_ which ranges over
almost the whole American continent and is found in Patagonia; _Geckotidæ_
by four genera, two of which,--_Caudiverbera_ and _Homonota_--are peculiar
to Chili, while _Sphærodactylus_ and _Cubina_ are Neotropical, the former
ranging to Patagonia, the latter to Chili; and lastly the American family
Iguanidæ represented by eight genera, no less than six being peculiar, (or
almost so,) to the South temperate region. These are _Leiodera_,
_Diplolæmus_ and _Proctrotretus_, ranging from Chili to Patagonia;
_Leiolæmus_, from Peru to Patagonia; _Phrymaturus_, confined to Chili, and
_Ptygoderus_ peculiar to Patagonia and Tierra del Fuego. The other two
genera, _Oplurus_ and _Leiosaurus_, are common to Chili and tropical South
America.
Tortoises appear to be scarce, a species of _Hydromedusa_ only being
recorded. Of the Amphibia, batrachia (frogs and toads) alone are
represented, and appear to be tolerably abundant, seventeen species having
been collected by Mr. Darwin in this sub-region. Species of the South
American genera _Phryniscus_, _Hylaplesia_, _Telmatobius_, _Cacotus_,
_Hylodes_, _Cyclorhamphus_, _Pleurodema_, _Cystignathus_, and _Leiuperus_,
are found in various localities, some extending even to the Straits of
Magellan,---the extreme southern limit of both Reptilia and Amphibia,
except one lizard (_Ptygoderus_) found by Professor Cunningham in Tierra
del Fuego. There are also four peculiar genera, _Rhinoderma_ belonging to
the Engystomidæ; _Alsodes_ and _Nannophryne_ to the Bombinatoridæ;
_Opisthodelphys_ to the Hylidæ; and _Calyptocephalus_ to the Discoglossidæ.
It thus appears, that in the Reptiles all the groups are typically
American, and that most of the peculiar genera belong to families which are
exclusively American. The Amphibia, on the other hand, present some
interesting external relations, but these are as much with Australia as
with the North temperate regions. The Bombinatoridæ are indeed Palæarctic,
but a larger proportion are Neotropical, and one genus inhabits New
Zealand. The Chilian genus _Calyptocephalus_ is allied to Australian
tropical genera. {42}The Neotropical genera of Ranidæ, five of which extend
to Chili and Patagonia, belong to a division which is Australian and
Neotropical, and which has species in the Oriental and Ethiopian regions.
_Fresh-water Fishes._--These present some peculiar forms, and some very
interesting phenomena of distribution. The genus _Percilia_ has been found
only in the Rio de Maypu in Chili; and _Percichthys_, also belonging to the
perch family, has five species confined to the fresh waters of South
Temperate America, and one far away in Java. _Nematogenys_ (1 sp.) is
peculiar to Chili; _Trichomycterus_ reaches 15,000 feet elevation in the
Andes,--both belonging to the Siluridæ; _Chirodon_ (2 sp.), belonging to
the Characinidæ, is peculiar to Chili; and several other genera of the same
family extend into this sub-region from Brazil. The family _Haplochitonidæ_
has a remarkable distribution; one of its genera, Haplochiton (2 sp.),
inhabiting Tierra del Fuego and the Falkland Islands, while the other,
_Prototroctes_, is found only in South Australia and New Zealand. Still
more remarkable is _Galaxias_ (forming the family Galaxidæ), the species of
which are divided between Temperate South America, and Australia, Tasmania,
and New Zealand; and there is even one species (_Galaxias attenuatus_)
which is found in the Chatham Islands, New Zealand, and Tasmania, as well
as in the Falkland Islands and Patagonia. _Fitzroya_ (1 sp.) is found only
at Montevideo; _Orestias_ (6 sp.) is peculiar to Lake Titicaca in the high
Andes of Bolivia; _Jenynsia_ (1 sp.) in the Rio de la Plata--all belonging
to the characteristic South American family of the Cyprinodontidæ.
_Insects._--It is in insects more than in any other class of animals, that
we find clear indications of a not very remote migration of northern forms,
along the great mountain range to South Temperate America, where they have
established themselves as a prominent feature in the entomology of the
country. The several orders and families, however, differ greatly in this
respect; and there are some groups which are only represented by
modifications of tropical forms, as we have seen to be almost entirely the
case in birds and reptiles.
{43}_Lepidoptera._--The butterflies of the South Temperate Sub-region are
not numerous, only about 29 genera and 80 species being recorded. Most of
these are from Chili, which is sufficiently accounted for by the general
absence of wood on the east side of the Andes from Buenos Ayres to South
Patagonia. The families represented are as follows: Satyridæ, with 11
genera and 27 species, are the most abundant; Nymphalidæ, 2 genera and 8
species; Lemoniidæ, 1 genus, 1 species; Lycænidæ, 3 genera, 8 species;
Pieridæ, 6 genera, 14 species; Papilionidæ, 2 genera, 8 species; Hesperidæ,
4 genera, 13 species. One genus of Satyridæ (_Elina_) and 2 of Pieridæ
(_Eroessa_ and _Phulia_) are peculiar to Chili. The following are the
genera whose derivation must be traced to the north temperate
zone:--_Tetraphlybia_, _Neosatyrus_, and 3 allied genera of 1 species each,
were formerly included under _Erebia_, a northern and arctic form, yet
having a few species in South Africa; _Argyrophorus_, allied to _Æneis_, a
northern genus; _Hipparchia_, a northern genus yet having a species in
Brazil;--all Satyridæ. The Nymphalidæ are represented by the typical north
temperate genus _Argynnis_, with 7 species in Chili; _Colias_, among the
Pieridæ, is usually considered to be a northern genus, but it possesses
representatives in South Africa, the Sandwich Islands, Malabar, New
Grenada, and Peru, as well as Chili, and must rather be classed as
cosmopolitan. These form a sufficiently remarkable group of northern forms,
but they are accompanied by others of a wholly Neotropical origin. Such are
_Stibomorpha_ with 6 species, ranging through South America to Guatemala,
and _Eteona_, common to Chili and Brazil (Satyridæ); _Apodemia_ (Lemoniidæ)
confined to Tropical America and Chili. _Hesperocharis_ and _Callidryas_
(Pieridæ), both tropical; and _Thracides_ (Hesperidæ) confined to Tropical
America and Chili. Other genera are widely scattered; as, _Epinephile_
found also in Mexico and Australia; _Cupido_, widely spread in the tropics;
_Euryades_, found only in La Plata and Paraguay, allied to South American
forms of _Papilio_, to the Australian _Eurycus_, and the northern
_Parnassius_; and _Heteropterus_, scattered in Chili, North America, and
Tropical Africa. We find then, among butterflies, a large north-temperate
element, {44}intermingled in nearly equal proportions with forms derived
from Tropical America; and the varying degrees of resemblances of the
Chilian to the northern species, seems to indicate successive immigrations
at remote intervals.
_Coleoptera._--It is among the beetles of South Temperate America that we
find some of the most curious examples of remote affinities, and traces of
ancient migrations. The Carabidæ are very well represented, and having been
more extensively collected than most other families, offer us perhaps the
most complete materials. Including the Cicindelidæ, about 50 genera are
known from the South Temperate Sub-region, the greater part from Chili, but
a good number also from Patagonia and the Straits of Magellan. Of these
more than 30 are peculiar, and most of them are so isolated that it is
impossible to determine with precision their nearest allies.
The only remarkable form of Cicindelidæ is _Agrius_, a genus allied to the
_Amblycheila_ and _Omus_ of N.W. America. Two genera of Carabidæ,
_Cascellius_ and _Baripus_, are closely allied to _Promecoderus_, an
Australian genus; and another, _Lecanomerus_, has one species in Chili and
the other in Australia. Five or six of the peculiar genera are undoubtedly
allied to characteristic Palæarctic forms; and such northern genera as
_Carabus_, _Pristonychus_, _Anchomenus_, _Pterostichus_, _Percus_,
_Bradycellus_, _Trechus_, and _Bembidium_, all absent from Tropical
America, give great support to the view that there is a close relation
between the insects of the northern regions and South Temperate America. A
decided tropical element is, however, present. _Tropopterus_ is near
_Colpodes_, a Tropical and South American genus; _Mimodromius_ and
_Plagiotelium_ are near _Calleida_, a South American genus; while
_Pachyteles_, _Pericompsus_, _Variopalpus_, and _Calleida_ are widely
spread American groups. The preponderance of northern forms seems, however,
to be undoubted.
Six Carabidæ are known from Juan Fernandez, 3 being identical with Chilian
species and 3 peculiar. As the island is 350 miles from the mainland, we
have here a proof of how readily insects may be transported great
distances.
{45}The Palæarctic affinity of the South Temperate Carabidæ may be readily
understood, if we bear in mind the great antiquity of the group, and the
known long persistence of generic and specific forms of Coleoptera; the
facility with which they may be transported to great distances by gales and
hurricanes, either on land or over the sea; and, therefore, the probability
that suitable stations would be rapidly occupied by species already adapted
to them, to the exclusion of those of the adjacent tracts which had been
specialised under different conditions. If, for example, we carry ourselves
back to the time when the Andes had only risen to half their present
altitude, and Patagonia had not emerged from the ocean (an epoch not very
remote geologically), we should find nearly all the Carabidæ of South
America, adapted to a warm, and probably forest-covered country. If, then,
a further considerable elevation of the land took place, a large temperate
and cold area would be formed, without any suitable insect inhabitants.
During the necessarily slow process of elevation, many of the tropical
Carabidæ would spread upwards, and some would become adapted to the new
conditions; while the majority would probably only maintain themselves by
continued fresh immigrations. But, as the mountains rose, another set of
organisms would make their way along the highest ridges. The abundance and
variety of the North Temperate Carabidæ, and their complete adaptation to a
life on barren plains and rock-strewn mountains, would enable them rapidly
to extend into any newly-raised land suitable to them; and thus the whole
range of the Rocky Mountains and Andes would obtain a population of
northern forms, which would overflow into Patagonia, and there, finding no
competitors, would develope into a variety of modified groups. This
migration was no doubt effected mainly, during successive glacial epochs,
when the mountain-range of the Isthmus of Panama, if moderately increased
in height, might become adapted for the passage of northern forms, while
storms would often carry insects from peak to peak over intervening forest
lowlands or narrow straits of sea. If this is the true explanation, we
ought to find no such preponderant northern element in groups which {46}are
proportionally less developed in cold and temperate climates. Our further
examination will show how far this is the case.
Lucanidæ.--Only four genera are known in the sub-region. Two are peculiar,
_Chiasognathus_ and _Streptocerus_, the former allied to Tropical American,
the latter to Australian genera; the other two genera are exclusively South
American.
Cetoniidæ.--These seem very scarce, only a few species of the Neotropical
genus _Gymnetis_ reaching Patagonia.
Buprestidæ.--These are rather numerous, many very beautiful species being
found in Chili. Nineteen genera are represented in South Temperate America,
and 5 of these are peculiar to it; 3 others are South American genera; 2
are Australian, and the remainder are wide-spread, but all are found also
in Tropical America. The only north-temperate genus is _Dicerca_, and even
this occurs also in the Antilles, Brazil, and Peru. Of the peculiar genera,
the largest, _Dactylozodes_ (26 sp.), has one species in South Brazil, and
is closely allied to _Hyperantha_, a genus of Tropical America;
_Epistomentis_ is allied to _Nascis_, an Australian genus; _Tyndaris_ is
close to _Acmoeodera_, a genus of wide range and preferring desert or dry
countries. The other two are single species of cosmopolitan affinities. On
the whole, therefore, the Buprestidæ are unmistakeably Neotropical in
character.
Longicorns.--Almost the whole of the South Temperate Longicorns inhabit
Chili, which is very rich in this beautiful tribe. About 75 genera and 160
species are known, and nearly half of the genera are peculiar. Many of the
species are large and handsome, rivalling in beauty those of the most
favoured tropical lands. Of the 8 genera of Prionidæ 6 are peculiar, but
all are allied to Tropical American forms except _Microplophorus_, which
belongs to a group of genera spread over Australia, Europe, and Mexico. The
Cerambycidæ are much more abundant, and their affinities more interesting.
Two (_Syllitus_ and _Pseudocephalus_) are common to Australia and Chili.
Twenty-three are Neotropical; and among these _Ibidion_, _Compsocerus_,
_Callideriphus_, _Trachyderes_, and _Xylocharis_, are best represented.
Twenty are {47}altogether peculiar, but most of them are more or less
closely allied to genera inhabiting Tropical America. Some, as the handsome
_Cheloderus_ and _Oxypeltus_, have no close allies in any part of the
world. _Holopterus_, though very peculiar, shows most resemblance to a New
Zealand insect. _Sibylla_, _Adalbus_, and _Phantagoderus_, have Australian
affinities; while _Calydon_ alone shows an affinity for north-temperate
forms. One species of the northern genus, _Leptura_, is said to have been
found at Buenos Ayres.
The Lamiidæ are less abundant. Nine of the genera are Neotropical. Two
(_Apomecyna_ and _Exocentrus_) are spread over all tropical regions. Ten
genera are peculiar; and most of these are related to Neotropical groups or
are of doubtful affinities. Only one, _Aconopterus_, is decidedly allied to
a northern genus, _Pogonochærus_. It thus appears, that none of the Lamiidæ
exhibit Australian affinities, although these are a prominent feature in
the relations of the Cerambycidæ.
It is evident, from the foregoing outline, that the insects of South
Temperate America, more than any other class of animals, exhibit a
connection with the north temperate regions, yet this connection is only
seen in certain groups. In Diurnal Lepidoptera and in Carabidæ, the
northern element is fully equal to the tropical, or even preponderates over
it. We have already suggested an explanation of this fact in the case of
the Carabidæ, and with the butterflies it is not more difficult. The great
mass of Neotropical butterflies are forest species, and have been developed
for countless ages in a forest-clad tropical country. The north temperate
butterflies, on the other hand, are very largely open-country species,
frequenting pastures, mountains, and open plains, and often wandering over
an extensive area. These would find, on the higher slopes of mountains, a
vegetation and conditions suited to them, and would occupy such stations in
less time than would be required to adapt and modify the forest-haunting
groups of the American lowlands. In those groups of insects, however, in
which the conditions of life are nearly the same as regards both temperate
and tropical species, the superior {48}number and variety of the tropical
forms has given them the advantage. Thus we find that among the Lucanidæ,
Buprestidæ, and Longicorns, the northern element is hardly perceptible.
Most of these are either purely Neotropical, or allied to Neotropical
genera, with the admixture, however, of a decided Australian element. As in
the case of the Amphibia and fresh-water fishes, the Australian affinity,
as shown by insects, is of two kinds, near and remote. We have a few genera
common to the two countries; but more commonly the genera are very
distinct, and the affinity is shown by the genera of both countries
belonging to a group peculiar to them, but which may be of very great age.
In the former case, we must impute some of the resemblance of the two
faunas to an actual interchange of forms within the epoch of existing
genera--a period of vast and unknown duration in the class of insects;
while in the latter case, and perhaps also in many of the former, it seems
more in accordance with the whole of the phenomena, to look upon most of
the instances as survivals, in the two southern temperate areas, of the
relics of groups which had once a much wider distribution. That this is the
true explanation, is suggested by the numerous cases of discontinuous and
scattered distribution we have had to notice, in which every part of the
globe, without exception, is implicated; and there is a reason why these
survivals should be rather more frequent in Australia and temperate South
America, inasmuch as these two areas agree in the absence of a considerable
number of otherwise cosmopolitan vertebrate types, and are also in many
respects very similar in climatic and other physical conditions. The
preponderating influence of the organic over the physical environment, as
taught by Mr. Darwin, leads us to give most weight to the first of the
above-mentioned causes; to which we may also impute such undoubted cases of
survival of ancient types as the Centetidæ of the Antilles and
Madagascar--both areas strikingly deficient in the higher vertebrate forms.
The probable mode and time of the cross migration between Australia and
South America, has been sufficiently discussed in our chapter on the
Australian region, when treating of the origin and affinities of the New
Zealand fauna.
{49}_Islands of the South Temperate Sub-region._
These are few, and of not much zoological interest. Tierra del Fuego,
although really an island, is divided from the mainland by so narrow a
channel that it may be considered as forming part of the continent. The
guanaco (_Auchenia huanaco_) ranges over it, and even to small islands
further south.
_The Falkland Islands._--These are more important, being situated about 350
miles to the east of Southern Patagonia; but the intervening sea is
shallow, the 100 fathom line of soundings passing outside the islands. We
have therefore reason to believe that they have been connected with South
America at a not distant epoch; and in agreement with this view we find
most of their productions identical, while the few that are peculiar are
closely allied to the forms of the mainland.
The only indigenous Mammals are a wolf-like fox (_Pseudalopex antarcticus_)
said to be found nowhere else, but allied to two other species inhabiting
Southern Patagonia; and a species of mouse, probably one of the American
genera _Hesperomys_ or _Reithrodon_.
Sixty-seven species of Birds have been obtained in these islands, but only
18 are land-birds; and even of these 7 are birds of prey, leaving only 11
Passeres. The former are all common South American forms, but one species,
_Milvago australis_, seems peculiar. The 11 Passeres belong to 9 genera,
all found on the adjacent mainland. Three, or perhaps four, of the species
are however peculiar. These are _Phrygilus melanoderus_, _P.
xanthogrammus_, _Cinclodes antarcticus_, and _Muscisaxicola macloviana_.
The wading and swimming birds are of little interest, except the penguins,
which are greatly developed; no less than eight species being found, five
as residents and three as accidental visitors.
No reptiles are known to inhabit these islands.
_Juan Fernandez._--This island is situated in the Pacific Ocean, about 400
miles west of Valparaiso in Chili. It is only a few miles in extent, yet it
possesses four land-birds, excluding the powerful Accipitres. These are
_Turdus falklandicus_; _Anæretes {50}fernandensis_, one of the Tyrannidæ;
and two humming-birds, _Eustephanus fernandensis_ and _E. galeritus_. The
first is a widespread South Temperate species, the two next are peculiar to
the island, while the last is a Chilian species which ranges south to
Tierra del Fuego. But ninety miles beyond this island lies another, called
"Mas-a-fuero," very much smaller; yet this, too, contains four species of
similar birds; one, _Oxyurus mas-a-fueræ_, allied to the wide-spread South
Temperate _O. spinicauda_, and _Cinclodes fusus_, a South Temperate
species--both Dendrocolaptidæ; with a humming-bird, _Eustephanus leyboldi_,
allied to the species in the larger island. The preceding facts are taken
from papers by Mr. Sclater in the _Ibis_ for 1871, and a later one in the
same journal by Mr. Salvin (1875). The former author has some interesting
remarks on the three species of humming-birds of the genus _Eustephanus_,
above referred to. The Chilian species, _E. galeritus_, is green in both
sexes. _E. fernandensis_ has the male of a fine red colour and the female
green, though differently marked from the female of _E. galeritus_. _E.
leyboldi_ (of Mas-a-fuera) has the male also red and the female green, but
the female is more like that of _E. galeritus_, than it is like the female
of its nearer ally in Juan Fernandez. Mr. Sclater supposes, that the
ancient parent form of these three birds had the sexes alike, as in the
present Chilian bird; that a pair (or a female having fertilised ova)
reached Juan Fernandez and colonised it. Under the action of sexual
selection (unchecked by some conditions which had impaired its efficacy on
the continent) the male gradually assumed a brilliant plumage, and the
female also slightly changed its markings. Before this change was completed
the bird had established an isolated colony on Mas-a-fuera; and here the
process of change was continued in the male, but from some unknown cause
checked in the female, which thus remains nearer the parent form. Lastly
the slightly modified Chilian bird again reached Juan Fernandez and exists
there side by side with its strangely altered cousin.
All the phenomena can thus be accounted for by known laws, on the theory of
very rare accidental immigrations from the {51}mainland. The species are
here so very few, that the greatest advocate for continental extensions
would hardly call such vast causes into action, to account for the presence
of these three birds on so small and so remote an island, especially as the
union must have continued down to the time of existing species. But if
accidental immigration has sufficed here, it will also assuredly have
sufficed where the islands are larger, and the chances of reaching them
proportionately greater; and it is because an important principle is here
illustrated on so small a scale, and in so simple a manner as to be almost
undeniable, that we have devoted a paragraph to its elucidation.
A few Coleoptera from Juan Fernandez present analogous phenomena. All
belong to Chilian genera, while a portion of them constitute peculiar
species.
Land-shells are rather plentiful, there being about twenty species
belonging to seven genera, all found in the adjacent parts of South
America; but all the species are peculiar, as well as four others found on
the island of Mas-a-fuera.
_III. Tropical North America, or the Mexican Sub-region._
This sub-region is of comparatively small extent, consisting of the
irregular neck of land, about 1,800 miles long, which connects the North
and South American continents. Almost the whole of its area is mountainous,
being in fact a continuation of the great range of the Rocky Mountains. In
Mexico it forms an extensive table-land, from 6,000 to 9,000 feet above the
sea, with numerous volcanic peaks from 12,000 to 18,000 feet high; but in
Yucatan and Honduras, the country is less elevated, though still
mountainous. On the shores of the Caribbean Sea and Gulf of Mexico, there
is a margin of low land from 50 to 100 miles wide, beyond which the
mountains rise abruptly; but on the Pacific side this is almost entirely
wanting, the mountains rising almost immediately from the sea shore. With
the exception of the elevated plateaus of Mexico and Guatemala, and the
extremity of the peninsula of Yucatan, the whole of Central America is
clothed with forests; and as its surface is much broken up into hill and
valley, and the volcanic {52}soil of a large portion of it is very fertile,
it is altogether well adapted to support a varied fauna, as it does a most
luxuriant vegetation. Although many peculiar Neotropical types are absent,
it yet possesses an ample supply of generic and specific forms; and, as far
as concerns birds and insects, is not perhaps inferior to the richest
portions of South America in the number of species to be found in equal
areas.
Owing to the fact that the former Republic of Mexico comprised much
territory that belongs to the Nearctic region, and that many Nearctic
groups extend along the high-lands to the capital city of Mexico itself,
and even considerably further south, there is much difficulty in
determining what animals really belong to this sub-region. On the
low-lands, tropical forms predominate as far as 28° N. latitude; while on
the cordilleras, temperate forms prevail down to 20°, and are found even
much farther within the tropics.
_Mammalia._--Very few peculiar forms of Mammalia are restricted to tropical
North America; which is not to be wondered at when we consider the small
extent of the country, and the facility of communication with adjacent
sub-regions. A peculiar form of tapir (_Elasmognathus bairdi_) inhabits
Central America, from Panama to Guatemala, and, with _Myxomys_, a genus of
Muridæ, are all at present discovered. _Bassaris_, a remarkable form of
Procyonidæ, has been included in the Nearctic region, but it extends to the
high-lands of Guatemala. _Heteromys_, a peculiar genus of Saccomyidæ or
pouched rats, inhabits Mexico, Honduras, Costa Rica, and Trinidad. Five
genera of monkeys extend here,--_Ateles_, _Mycetes_, _Cebus_,
_Nyctipithecus_, and _Saimiris_; the two former alone reaching Mexico, the
last only going as far as Costa Rica. Other typical Neotropical forms are
_Galera_, the tayra, belonging to the weasel family; _Nasua_, the
coatimundi; _Dicotyles_, the peccary; _Cercolabes_, the tree porcupine;
_Dasyprocta_, the agouti; _Cælogenys_, the paca; _Choloepus_, and
_Arctopithecus_, sloths; _Cyclothurus_, an ant-eater; _Tatusia_, an
armadillo; and _Didelphys_, oppossum. Of Northern forms, _Sorex_, _Vulpes_,
_Lepus_, and _Pteromys_ reach Guatemala.
_Birds._--The productiveness of this district in bird life, may {53}be
estimated from the fact, that Messrs. Salvin and Sclater have catalogued
more than 600 species from the comparatively small territory of Guatemala,
or the portion of Central America between Mexico and Honduras. The great
mass of the birds of this sub-region are of Neotropical families and
genera, but these are intermingled with a number of migrants from temperate
North America, which pass the winter here; with some northern forms on the
high-lands; and with a considerable number of peculiar genera, mostly of
Neotropical affinities.
The genera of birds peculiar to this sub-region belong to the following
families:--Turdidæ (2 genera); Troglodytidæ (1 gen.); Vireonidæ (1 gen.);
Corvidæ (2 gen.); Ampelidæ (1 gen.); Tanagridæ (1 gen.); Fringillidæ (2
gen.); Icteridæ (1 gen.); Formicariidæ (2 gen.); Tyrannidæ (2 gen.);
Cotingidæ (1 gen.); Momotidæ (1 gen.); Trogonidæ (1 gen.); Trochilidæ (14
gen.); Conuridæ (1 gen.); Cracidæ (2 gen.); Strigidæ (1 gen.); in all 37
genera of land-birds. The Neotropical families that do not extend into this
sub-region are, Pteroptochidæ; the sub-family _Furnariinæ_ of the
Dendrocolaptidæ; the sub-family _Conophaginæ_ of the Tyrannidæ; the
sub-family _Rupicolinæ_ of the Cotingidæ; Phytotomidæ; Todidæ;
Opisthocomidæ; Chionididæ; Thinocoridæ; Cariamidæ; Psophiidæ; Eurypygidæ;
Palamedeidæ; and Struthionidæ. On the other hand Paridæ, Certhiidæ,
Ampelidæ, and Phasianidæ, are northern families represented here, but which
do not reach South America; and there are also several northern genera and
species, of Turdidæ, Troglodytidæ, Mniotiltidæ, Vireonidæ, Fringillidæ,
Corvidæ, Tetraonidæ, and Strigidæ, which are similarly restricted. Some of
the most remarkable of the Neotropical genera only extend as far as Costa
Rica and Veragua,--countries which possess a rich and remarkable fauna.
Here only are found an umbrella bird, (_Cephalopterus glabricollis_); a
bell bird (_Chasmorhynchus tricarunculatus_); and species of _Dacnis_
(Ceroebidæ), _Buthraupis_, _Eucometis_, _Tachyphonus_ (Tanagridæ),
_Xiphorhynchus_ (Dendrocolaptidæ); _Hypocnemis_ (Formicariidæ);
_Euscarthmus_ (Tyrannidæ); _Attila_ (Cotingidæ); _Piprites_ (Pipridæ);
_Capito_, _Tetragonops_ (Megalæmidæ); _Selenidera_ (Rhamphastidæ);
_Neomorphus_ {54}(Cuculidæ); _Monasa_ (Bucconidæ); many genera of
Trochilidæ; and _Nothocercus_ (Tinamidæ); none of which extend further
north. A considerable number of the peculiar genera noted above, are also
found in this restricted area, which is probably one of the richest
ornithological districts on the globe.
_Reptiles._--These are much less known than the preceding classes, but they
afford several peculiar and interesting forms. Snakes are perhaps the least
remarkable; yet there are recorded 4 peculiar genera of Calamariidæ, 1 of
Colubridæ, 1 of Homalopsidæ, 3 of Dipsadidæ; while _Boa_ and _Elaps_ are in
common with South America. Lizards are much more specially developed.
_Chirotes_, one of the Amphisbænians, is confined to Mexico and the
southern part of the Nearctic region; _Heloderma_ forming a peculiar
family, Helodermidæ, is Mexican only; _Abronia_ and _Barissia_ (Zonuridæ)
are also Mexican, as is _Siderolampus_ belonging to the Scincidæ, while
_Blepharactitis_ (same family) inhabits Nicaragua; _Brachydactylus_, one of
the geckoes, is from Costa Rica; while _Phymatolepis_, _Lamanctus_,
_Corytheolus_, _Cachrix_, _Corythophanes_ and _Chamæleopsis_, all belonging
to the Iguanidæ, are confined to various parts of the sub-region. In the
same family we have also the Antillean, _Cyclura_, and the Nearctic
_Phrynosoma_ and _Tropidolepis_, as well as the wide-spread American genus
_Anolius_.
Among the tortoises, _Staurotypus_, allied to _Chelydra_, is found in
Mexico and Guatemala; and another genus, _Claudius_, has been lately
described from Mexico.
_Amphibia._--These are chiefly Batrachians; _Rhinophryna_ (forming a
peculiar family) being confined to Mexico; _Triprion_, a genus of Hylidæ,
inhabiting Yucatan, with _Leyla_ and _Strabomantis_ (Polypedatidæ) found
only in Costa Rica and Veragua, are peculiar genera. The Salamandridæ, so
abundant in the Nearctic region, are represented by a few species of
_Amblystoma_ and _Spelerpes_.
_Fresh-water fish._--Since the British Museum catalogue was published, a
valuable paper by Dr. Günther, in the Transactions of the Zoological
Society for 1868, furnishes much additional information on the fishes of
Central America. In that part of the region south of Mexico, 106 species of
fresh-water fishes are {55}enumerated; and 17 of these are found in streams
flowing into both the Atlantic and Pacific Oceans. On the whole, 11
families are represented among the fresh-water fish, and about 38 genera.
Of these, 14 are specially Nearctic,--_Amiurus_ (Siluridæ); _Fundulus_
(Cyprinodontidæ); _Sclerognathus_ (Cyprinidæ); and _Lepidosteus_
(Ganoidei). A much larger number are Neotropical; and several Neotropical
genera, as _Heros_ and _Poecilia_, are more largely developed here than in
any other part of the region. There are also a considerable number of
peculiar genera;--_Petenia_, _Theraps_, and _Neotrophus_ (Chromides);
_Ælurichthys_ (Siluridæ); _Chalcinopsis_ (Characniidæ); _Characodon_,
_Belonesox_, _Pseudoxiphophorus_, _Platypoecilus_, _Mollienesia_, and
_Xiphophorus_ (Cyprinodontidæ). A few peculiar Antillean forms are also
present; as _Agonostoma_ (Mugilidæ); _Gambusia_ and _Girardinuus_
(Cyprinodontidæ). The other families represented are Percidæ (1 genus);
Pristopomatidæ (2 gen.); Gobiidæ (1 gen.); Clupeidæ (2 gen.); and Gymnotidæ
(1 genus).
On the whole the fish-fauna is typically Neotropical, but with a small
infusion of Nearctic forms. There are a considerable proportion of peculiar
genera, and almost all the species are distinct from those of other
countries. The predominant family is that of the Cyprinodontidæ,
represented by 12 genera; and the genus _Heros_ (Chromidæ) has here its
maximum development, containing between thirty and forty species. Dr.
Günther considers that a number of sub-faunas can be distinguished,
corresponding to some extent, with the islands into which the country would
be divided by a subsidence of about 2,000 feet. The most important of these
divisions is that separating Honduras from Costa Rica, and as it also
divides a very marked ornithological fauna we have every reason to believe
that such a division must have existed during the latter portion of the
tertiary epoch. We shall find some farther evidence of this division in the
next class.
_Insects._--The butterflies of various parts of Central America and Mexico,
having been largely collected, offer us some valuable evidence as to the
relations of this sub-region. Their general character is wholly
Neotropical, about one half of the {56}South American genera being found
here. There are also a few peculiar genera, as, _Drucina_ (Satyridæ);
_Microtia_ (Nymphalidæ); _Eumæus_ (Lycænidæ); and _Eucheira_ (Pieridæ).
_Clothilda_ (Nymphalidæ) is confined to this sub-region and the Antilles.
The majority of the genera range over the whole sub-region from Panama to
Mexico, but there are a considerable number, comprising many of the most
characteristic South American forms, which do not pass north of Costa Rica
or Nicaragua. Such are _Lycorea_, _Ituna_, _Thyridia_, _Callithomia_,
_Oleria_ and _Ceratina_,--all characteristic South American groups of
Danaidæ; _Pronophila_ and _Dynastor_ (Satyridæ); _Protogonius_, _Pycina_,
_Prepona_, _Nica_, _Ectima_ and _Colænis_ (Nymphalidæ); _Eurybia_ and
_Methonella_ (Nemeobiidæ); _Hades_, and _Panthemos_ (Erycinidæ).
_Coleoptera._--These present some interesting features, but owing to their
vast number only a few of the more important families can be noticed.
Cicindelidæ.--The only specially Neotropical genera recorded as occurring
in this sub-region, are _Ctenostoma_ and _Hiresia_, both reaching Mexico.
Carabidæ.--Several genera are peculiar. _Molobrus_ is found in all parts of
the sub-region, while _Onychopterygia_, _Phymatocephalus_, and
_Anisotarsus_ are Mexican only. There are about 20 South American genera,
most of which extend to Mexico, and include such characteristic Neotropical
forms as _Agra_, _Callida_, _Coptodera_, _Pachyteles_, _Ardistomus_,
_Aspidoglossa_, _Stenocrepis_, and _Pelecium_.
Lucanidæ.--Of this important family there is, strange to say, not a single
species recorded in Gemminger and Harold's catalogue up to 1868! It is
almost impossible that they can be really absent; yet their place seems to
he, to some extent, supplied by an unusual development of the allied
Passalidæ, of which there are five South American and six peculiar genera.
Cetoniidæ.--All the larger South American genera extend to Mexico, which
country possesses 3 peculiar forms, _Ischnoscelis_, _Psilocnemis_, and
_Dialithus_; while _Trigonopeltastes_ is characteristic, having 4 Mexican,
1 Brazilian, and 1 North American species.
{57}Buprestidæ.--In this family there are no peculiar genera. All the large
South American groups are absent, the only important and characteristic
genus being _Stenogaster_.
Longicorns.--This important group is largely developed, the country being
well adapted to them; and their distribution presents some features of
interest.
In the Prionidæ there are 6 peculiar genera, the largest being _Holonotus_
with 3 species; two others, _Derotrachus_ and _Mallaspis_, are
characteristic; 3 more are common to South America, and 1 to Cuba. The
Cerambycidæ are much more numerous, and there are 24 peculiar genera, the
most important being _Sphenothecus_, _Entomosterna_, and _Cyphosterna_;
while _Crioprosopus_ and _Metaleptus_ are characteristic of the sub-region,
although extending into South America; about 12 Neotropical genera extend
to Mexico or Guatemala, while 12 more stop short, as far as yet known, at
Nicaragua. Lamiidæ have a very similar distribution; 13 genera are
peculiar, the most important being _Monilema_, _Hamatoderus_, and
_Carneades_, while _Phæa_ and _Lagochirus_ are characteristic. About
sixteen typical Neotropical genera extend to Mexico, and 15 more only reach
Nicaragua, among which are such important genera as _Anisopus_,
_Lepturgus_, and _Callia_.
The land-shells are not sufficiently known to furnish any corresponding
results. They are however mostly of South American genera, and have
comparatively little affinity for those of the Antilles.
_Relations of the Mexican sub-region to the North and South American
Continents._--The sudden appearance of numerous South American forms of
Edentata in temperate North America, in Post-Tertiary times, as narrated in
Chapter VII., together with such facts as the occurrence of a considerable
number of identical species of sea fish on the two sides of the Central
American isthmus, render it almost certain that the union of North and
South America is comparatively a recent occurrance, and that during the
Miocene and Pliocene periods, they were separated by a wide arm of the sea.
The low country of Nicaragua was probably the part submerged, leaving the
highlands of Mexico and Guatemala still united with the North {58}American
continent, and forming part of the Tertiary "Nearctic region." This is
clearly indicated both by the many Nearctic forms which do not pass south
of Nicaragua, of which the turkeys (_Meleagris_) are a striking example,
and by the comparative poverty of this area in typical Neotropical groups.
During the Miocene period there was not that marked diversity of climate
between North and South America that now prevails; for when a luxuriant
vegetation covered what are now the shores of the Arctic Ocean, the country
south of the great lakes must have been almost or quite tropical. At an
early Tertiary period, the zoological differences of the Nearctic and
Neotropical regions were probably more radical than they are now, South
America being a huge island, or group of islands--a kind of Australia of
the New World, chiefly inhabited by the imperfectly organized Edentata;
while North America abounded in Ungulata and Carnivora, and perhaps formed
a part of the great Old World continent. There were also one or more very
ancient unions (in Eocene or Miocene times) of the two continents,
admitting of the entrance of the ancestral types of Quadrumana into South
America, and, somewhat later, of the Camelidæ; while the isthmus south of
Nicaragua was at one time united to the southern continent, at another made
insular by subsidence near Panama, and thus obtained that rich variety of
Neotropical types that still characterises it. When the final union of the
two continents took place, the tropical climate of the lower portions of
Guatemala and Mexico would invite rapid immigration from the south; while
some northern forms would extend their range into and beyond the newly
elevated territory. The Mexican sub-region has therefore a composite
character, and we must not endeavour too rigidly to determine its northern
limits, nor claim as exclusively Neotropical, forms which are perhaps
comparatively recent immigrants; and it would perhaps be a more accurate
representation of the facts, if we were to consider all the highlands of
Mexico and Guatemala above the limits of the tropical forests, as still
belonging to the Nearctic region, of which the whole country so recently
formed a part.
The long-continued separation of North and South America {59}by one or more
arms of the sea, as above indicated, is further rendered necessary by the
character of the molluscan fauna of the Pacific shores of tropical America,
which is much more closely allied to that of the Caribbean sea, and even of
West Africa, than to that of the Pacific islands. The families and many of
the genera are the same, and a certain proportion of very closely allied or
identical species, shows that the union of the two oceans continued into
late Tertiary times. When the evidence of both land and sea animals support
each other as they do here, the conclusions arrived at are almost as
certain as if we had (as we no doubt some day shall have) geological proof
of these successive subsidences.
_Islands of the Mexican Sub-region._--The only islands of interest
belonging to this sub-region, are Tres Marias and Socorro, recently
investigated by Col. Grayson for some of the American Natural History
societies.
Tres Marias consist of four small islands lying off the coast of
north-western Mexico, about 70 miles from San Blas. The largest is about 15
miles long by 10 wide. They are of horizontally stratified deposits, of
moderate height and flat-topped, and everywhere covered with luxuriant
virgin forests. They appear to lie within the 100 fathom line of soundings.
Fifty-two species of birds, of which 45 were land-birds, were collected on
these islands. They consisted of 19 Passeres; 11 Picariæ (7 being
humming-birds); 10 Accipitres; 2 parrots, and 3 pigeons. All were Mexican
species except 4, which were new, and presumably peculiar to the islands,
and one tolerably marked variety. The new species belong to the following
genera;--_Parula_ and _Granatellus_ (Mniotiltidæ); _Icterus_ (Icteridæ);
and _Amazilia_ (Trochilidæ). A small _Psittacula_ differs somewhat from the
same species on the mainland.
There are a few mammalia on the islands; a rabbit (_Lepus_) supposed to be
new; a very small opossum (_Didelphys_), and a racoon (_Procyon_). There
are also several tree-snakes, a _Boa_, and many lizards. The occurrence of
so many mammalia and snakes is a proof that these islands have been once
joined to the mainland; but the fact that some of the species of both birds
and {60}mammals are peculiar, indicates that the separation is not a very
recent one. At the same time, as all the species are very closely allied to
those of the opposite coasts when not identical, we may be sure that the
subsidence which isolated them is not geologically remote.
Socorro, the largest of the Revillagigedo Islands, is altogether different
from the Tres Marias. It is situated a little further south (19 S.
Latitude), and about 300 miles from the coast, in deep water. It is about
2,000 feet high, very rugged and bare, and wholly volcanic. No mammalia
were observed, and no reptiles but a small lizard, a new species of a genus
(_Uta_) characteristic of the deserts of N.-Western Mexico. The only
observed land-shell (_Orthalicus undatus_) also inhabits N.-W. Mexico. Only
14 species of birds were obtained, of which 9 were land-birds; but of these
4 were new species, one a peculiar variety, and another (_Parula
insularis_) a species first found in the Tres Marias. With the exception of
this bird and a _Buteo_, all the land-birds belonged to different _genera_
from any found on the Tres Marias, though all were Mexican forms. The
peculiar species belonged to the genera _Harporhynchus_ (Turdidæ);
_Troglodytes_ (Troglodytidæ); _Pipilo_ (Fringillidæ); _Zenaidura_
(Columbidæ); and a variety of _Conurus holochrous_ (Psittacidæ).
The absence of mammals and snakes, the large proportion of peculiar
species, the wholly volcanic nature of these islands, and their situation
in deep water 300 miles from land,--all indicate that they have not formed
part of the continent, but have been raised in the ocean; and the close
relation of their peculiar species to those living in N.-Western Mexico,
renders it probable that their antiquity is not geologically great.
The Cocos Islands, about 300 miles S.-W. of the Isthmus of Panama, are
known to possess one peculiar bird, a cuckoo of the _Coccyzus_ type, which
is considered by some ornithologists to constitute a peculiar genus,
_Nesococcyx_.
_IV. The West Indian Islands, or Antillean Sub-region._
The West Indian islands are, in many respects, one of the most interesting
of zoological sub-regions. In position they {61}form an unbroken chain
uniting North and South America, in a line parallel to the great Central
American isthmus; yet instead of exhibiting an intermixture of the
productions of Florida and Venezuela, they differ widely from both these
countries, possessing in some groups a degree of speciality only to be
found elsewhere in islands far removed from any continent. They consist of
two very large islands, Cuba and Hayti;[3] two of moderate size, Jamaica
and Portorico; and a chain of much smaller islands, St. Croix, Anguilla,
Barbuda, Antigua, Guadeloupe, Dominica, Martinique, St. Lucia, St. Vincent,
Barbadoes, and Grenada, with a host of intervening islets. Tobago,
Trinidad, Margarita, and Curaçao, are situated in shallow water near the
coast of South America, of which they form part zoologically. To the north
of Cuba and Hayti are the Bahamas, an extensive group of coral reefs and
islands, 700 miles long, and although very poor in animal life, belonging
zoologically to the Antilles. All the larger islands, and most of the
smaller ones (except those of coral formation) are very mountainous and
rocky, the chains rising to about 8,000 feet in Hayti and Jamaica, and to
nearly the same height in Cuba. All, except where they have been cleared by
man, are covered with a luxuriant forest vegetation; the temperature is
high and uniform; the rains ample; the soil, derived from granitic and
limestone rocks, exceedingly fertile; and as the four larger islands
together are larger than Great Britain, we might expect an ample and
luxuriant fauna. The reverse is however the case; and there are probably no
land areas on the globe, so highly favoured by nature in all the essentials
for supporting animal life, and at the same time so poor in all the more
highly organised groups of animals. Before entering upon our sketch of the
main features of this peculiar but limited fauna, it will be well to note a
few peculiarities in the physical structure of the islands, which have an
important bearing on their past {62}history, and will enable us to account
for much that is peculiar in the general character of their natural
productions.
If we draw a line immediately south of St. Croix and St. Bartholomew, we
shall divide the Archipelago into two very different groups. The southern
range of islands, or the Lesser Antilles, are, almost without exception,
volcanic; beginning with the small detached volcanoes of Saba and St.
Eustatius, and ending with the old volcano of Grenada. Barbuda and Antigua
are low islands of Tertiary or recent formation, connected with the
volcanic islands by a submerged bank at no great depth. The islands to the
north and west are none of them volcanic; many are very large, and these
have all a central nucleus of ancient or granitic rocks. We must also note,
that the channels between these islands are not of excessive depth, and
that their outlines, as well as the direction of their mountain ranges,
point to a former union. Thus, the northern range of Hayti is continued
westward in Cuba, and eastward in Portorico; while the south-western
peninsula extends in a direct line towards Jamaica, the depth between them
being 600 fathoms. Between Portorico and Hayti there is only 250 fathoms;
while close to the south of all these islands the sea is enormously deep,
from more than 1,000 fathoms south of Cuba and Jamaica, to 2,000 south of
Hayti, and 2,600 fathoms near the south-east extremity of Portorico. The
importance of the division here pointed out will be seen, when we state,
that indigenous mammalia of peculiar genera are found on the western group
of islands only; and it is on these that all the chief peculiarities of
Antillian zoology are developed.
_Mammalia._--The mammals of the West Indian Islands are exceedingly few,
but very interesting. Almost all the orders most characteristic of South
America are absent. There are no monkeys, no carnivora, no edentata.
Besides bats, which are abundant, only two orders are represented; rodents,
by peculiar forms of a South American family; and insectivora (an order
entirely wanting in South America) by a genus belonging to a family largely
developed in Madagascar and found nowhere else. The early voyagers mention
"Coatis" and "Agoutis" as being {63}found in Hayti and the other large
islands, and it is not improbable that species allied to _Nasua_ and
_Dasyprocta_ did exist, and have been destroyed by the dogs of the
invaders; though, on the other hand, these names may have been applied to
the existing species, which do bear some general resemblance to these two
forms.
The Chiroptera, or bats, are represented by a large number of species and
by several peculiar genera. The American family of Phyllostomidæ or
vampires, has six genera in the Antilles, of which three, _Lonchorina_,
_Brachyphylla_, and _Phyllonycteris_, are peculiar, the latter being found
only in Cuba. The Vespertilionidæ have four genera, of which one,
_Nycticellus_, is confined to Cuba. There are six genera of Noctilionidæ,
of which one, _Phyllodia_, is confined to Jamaica.
The Insectivora are represented by the genus _Solenodon_, of which two
species are known, one inhabiting Cuba the other Hayti. These are small
animals about the size of a cat, with long shrew-like snout, bare rat-like
tail, and long claws. Their peculiar dentition and other points of their
anatomy shows that they belong to the family Centetidæ, of which five
different genera inhabit Madagascar; while there is nothing closely allied
to them in any other part of the world but in these two islands.
Seals are said to be found on the shores of some of the islands, but they
are very imperfectly known.
The rodents belong to the family Octodontidæ, or, according to some
authors, to the Echimyidæ, both characteristic South American groups. They
consist of two genera, _Capromys_, containing three or four species
inhabiting Cuba and Jamaica; while _Plagiodontia_ (very closely allied) is
confined to Hayti. A peculiar mouse, a species of the American genus
_Hesperomys_, is said to inhabit Hayti and Martinique, and probably other
islands. A _Dasyprocta_ or agouti, closely allied to, if not identical
with, a South American species, inhabits St. Vincent, St. Lucia, and
Grenada, and perhaps St. Thomas, and is the only mammal of any size
indigenous to the Lesser Antilles. All the islands in which sugar is
cultivated are, however, overrun with European rats and mice, and it is not
improbable that these may have {64}starved out and exterminated some of the
smaller native rodents.
_Birds._--The birds of the Antilles, although very inferior in number and
variety to those of the mainland, are yet sufficiently abundant and
remarkable, to offer us good materials for elucidating the past history of
the country, when aided by such indications as geology and physical
geography can afford.
The total number of land-birds which are permanent residents in the West
India islands is, as nearly as can be ascertained from existing materials,
203. There are, in addition to this number, according to Prof. Baird, 88
migrants from North America, which either spend the winter in some of the
islands or pass on to Central or South America. These migrants belong to 55
genera, and it is an interesting fact that so many as 40 of these genera
have no resident representatives in the islands. This is important, as
showing that this northern migration is probably a recent and superficial
phenomenon, and has not produced any (or a very slight) permanent effect on
the fauna. The migratory genera which have permanent residents, and almost
always representative species, in the islands, are in most cases
characteristic rather of the Neotropical than of the Nearctic fauna, as the
following list will show; _Turdus_, _Dendroeca_, _Vireo_, _Polioptila_,
_Agelæus_, _Icterus_, _Contopus_, _Myiarchus_, _Tyrannus_, _Antrostomus_,
_Chordeiles_, _Coccyzus_, _Columba_. By far the larger part of these birds
visit Cuba only; 81 species being recorded as occurring in that island,
while only 31 have been found in Jamacia, 12 in Porto Rico and St. Croix,
and 2 in Tobago and Trinidad. Setting aside these migratory birds, as
having no bearing on the origin of the true Antillean fauna, we will
discuss the residents somewhat in detail.
The resident land-birds (203 in number) belong to 95 genera and 26
families. Of these families 15 are cosmopolitan or nearly so--Turdidæ,
Sylviidæ, Corvidæ, Hirundinidæ, Fringillidæ, Picidæ, Cuculidæ,
Caprimulgidæ, Cypselidæ, Trogonidæ, Psittacidæ, Columbidæ, Tetraonidæ,
Falconidæ, and Strigidæ; 5 are American only--Vireonidæ, Mniotiltidæ,
Icteridæ, Tyrannidæ, Trochilidæ; 4 are Netropical only or almost
{65}exclusively--Coerebidæ, Tanagridæ, Cotingidæ, Conuridæ; 1 is Antillean
only--Todidæ; while 1--Ampelidæ--is confined (in the western hemisphere) to
North America, and almost to the Nearctic region. Of the 95 genera, no less
than 31, or almost exactly one-third, are peculiar; while of the 203
resident species, 177 are peculiar, the other 26 being all inhabitants of
South or Central America. Considering how closely the islands approach the
continent in several places--Florida, Yucatan, and Venezuela--this amount
of speciality in such locomotive creatures as birds, is probably unexampled
in any other part of the globe. The most interesting of these peculiar
genera are the following: 4 of Turdidæ, or thrushes--1 confined to the
large islands, 1 to the whole archipelago, while 2 are limited to the
Lesser Antilles; 2 genera of Tanagridæ, confined to the larger islands; 2
of Trogonidæ, also confined to the larger islands; 5 of hummingbirds, 3
confined to the Greater, 1 to the Lesser Antilles; 2 of cuckoos, one
represented in all the large islands, the other in Jamaica only; 2 of owls,
one peculiar to Jamaica, the other represented in St. Croix, St. Thomas,
Portorico, and Cuba; and lastly, _Todus_, constituting a peculiar family,
and having representative species in each of the larger islands, is
especially interesting because it belongs to a group of families which are
wholly Neotropical--the Momotidæ, Galbulidæ, and Todidæ. The presence of
this peculiar form, with 2 trogons; 10 species of parrots, all but one
peculiar; 16 peculiar humming-birds belonging to 8 genera; a genus of
Cotingidæ; 10 peculiar tanagers belonging to 3 genera; 9 Coerebidæ of 3
genera; together with species of such exclusively Netropical genera as
_Coereba_, _Certhiola_, _Sycalis_, _Phonipara_, _Elainea_, _Pitangus_,
_Campephilus_, _Chloronerpes_, _Nyctibius_, _Stenopsis_, _Lampornis_,
_Calypte_, _Ara_, _Chrysotis_, _Zenaida_, _Leptoptila_, and _Geotrygon_,
sufficiently demonstrate the predominant affinities of this fauna; although
there are many cases in which it is difficult to say, whether the ancestors
of the peculiar genera or species may not have been derived from the
Nearctic rather than from the Neotropical region.
The several islands differ considerably in their apparent
{66}productiveness, but this is, no doubt, partly due to our knowledge of
Cuba and Jamaica being much more complete than of Hayti. The species of
resident land-birds at present known are as follows:--
Cuba 68 species of which 40 are peculiar to it.
Hayti 40 " " 17 " "
Jamaica 67 " " 41 " "
Portorico 40 " " 15 " "
Lesser Antilles 45 " " 24 " "
If we count the peculiar genera of each island, and reckon as (½) when a
genus is common to two islands only, the numbers are as follows:--Cuba 7½,
Hayti 3½, Jamaica 8½, Portorico 1, Lesser Antilles 3½. These figures show
us, that although Jamaica is one of the smaller and the most isolated of
the four chief islands, it yet stands in the first rank, both for the
number of its species and of its peculiar forms of birds,--and although
this superiority may be in part due to its having been more investigated,
it is probably not wholly so, since Cuba has also been well explored. This
fact indicates, that the West Indian islands have undergone great changes,
and that they were not peopled by immigration from surrounding countries
while in the condition we now see them; for in that case the smaller and
more remote islands would be very much poorer, while Cuba, which is not
only the largest, but nearest to the mainland in two directions, would be
immensely richer, just as it really is in migratory birds.
The number of birds common to the four larger islands is very
small--probably not more than half a dozen; between 20 and 30 are common to
some two of the islands (counting the Lesser Antilles as one island) and a
few to three; but the great mass of the species (at least 140) are confined
each to some one of the five islands or groups we have indicated. This is
an amount of isolation and speciality, probably not to be equalled
elsewhere, and which must have required a remarkable series of physical
changes to bring about. What those changes probably were, we shall be in a
better position to consider when we have completed our survey of the
various classes of land animals.
Plate XVII.
[Illustration]
A SCENE IN CUBA, WITH CHARACTERISTIC ANIMALS.
{67}In the preceding enumeration the Bahamas have been included with Cuba,
as regards the birds they have in common; but they possess some half dozen
species not found elsewhere, and even one central American genus of
humming-birds (_Doricha_) not found in any other part of the Antilles. We
have thus given Cuba rather more peculiar species than it really possesses,
so that the proportionate richness of Jamaica is rather greater than shown
by our figures.
The destruction of the forests and the increase of population, with,
perhaps, the use of firearms, seem to have led to the extermination of some
species of birds in the smaller islands. Professor Newton has called
attention to the work of M. Ledru, who, in 1796, described the birds of St.
Thomas. He mentions a parrot and a parroquet in the island, the latter only
being now known, and very scarce; also a green pigeon and a tody, both now
unknown. No less than six species of parrots are said to have been formerly
found in Guadeloupe and Martinique, which are now extinct.
_Plate XVII. Illustrating the peculiar Mammalia and Birds of the
Antilles._--The scene of this illustration is Cuba, the largest of the West
Indian islands, and one in which all its peculiar zoological features are
well developed. In the foreground is the agouta (_Solenodon cubanus_), a
remarkable insectivorous animal which, with another species inhabiting
Hayti, has no allies on the American continent; nor anywhere in the world
but in Madagascar, where a group of animals are found constituting the
family Centetidæ, to which _Solenodon_ is said undoubtedly to belong. Above
it are a pair of hutias (_Capromys fournieri_), rat-like animals belonging
to the South American family Octodontidæ. They live in the forests, and
climb trees readily, eating all kinds of vegetable food. Three species of
the genus are known, which are found only in Cuba and Jamaica. Just above
these animals is a white-breasted trogon (_Prionoteles temnurus_), confined
to Cuba, and the only species of the genus. Near the top of the picture are
a pair of todies (_Todus multicolor_), singular little insectivorous birds
allied to the motmots, but forming a very distinct family which is confined
to the islands of the {68}Greater Antilles. They are beautifully-coloured
birds,--green above, red and white beneath, and are exceedingly active in
their movements. To the right are a pair of small humming-birds
(_Sporadinus ricordi_), not very remarkable in this beautiful family, but
introduced here because they belong to a genus which is confined to the
Greater Antilles.
_Table of distribution of West-Indian Birds._--As the birds of the West
Indian islands are particularly interesting and their peculiarities
comparatively little known, we give here a table of the genera of
land-birds, compiled from all available sources of information. Owing to
the numerous independent observations on which it is founded, the
discrepancies of nomenclature, and uncertainty in some cases as to the
locality of species, it can only be looked upon as an approximative summary
of the existing materials on Antillean ornithology.
_TABLE OF THE RESIDENT LAND-BIRDS OF THE ANTILLES._
NOTE.--Genera confined to the West Indies are in Italics. An (_a_) after
(1) indicates a species common to two islands: but where there are two or
more species in an island, or the localities are doubtful, this indication
cannot be given. All species not otherwise noted are peculiar to the
Antilles.
Key to columns:
Column 1 Cuba.
" 2 Bahamas.
" 3 Hayti.
" 4 Jamaica.
" 5 Portorico & St. Croix.
" 6 Lesser Antilles.
" 7 Total resident species.
----------------+-----------------------------+----+---------------------
| Number of Species in | |
Family and | each Island. | |
Genus. +----+----+----+----+----+----+ | Remarks.
| 1 | 2 | 3 | 4 | 5 | 6 | 7 |
----------------+----+----+----+----+----+----+----+---------------------
TURDIDÆ. | | | | | | | |
Turdus | -- | -- | -- | 1 | -- | -- | 1 | Five species migrate
| | | | | | | | to Cuba
_Mimocichla_ | 2 | 1 | 1 | 1 | -- | -- | 5 |
_Margarops_ | -- | -- | 1a | -- | 1a | 3 | 4 | Martinique, St.
| | | | | | | | Lucia, Guada.
_Rhamphocinclus_ -- | -- | -- | -- | -- | 1 | 1 | Martinique and St.
| | | | | | | | Lucia
_Cinclocerthia_| -- | -- | -- | -- | -- | 3 | 3 | Nevis to St. Lucia
Mimus | 1 | 1 | -- | 1 | (?)| -- | 3 | Another species
| | | | | | | | migrates to the
| | | | | | | | Antilles
| | | | | | | |
SYLVIIDÆ. | | | | | | | |
Myiadestes | 1 | -- | -- | 1 | -- | 1 | 3 | St. Lucia
Polioptila | 1 | -- | -- | -- | -- | -- | 1 |
| | | | | | | |
VIREONIDÆ. | | | | | | | |
Vireosylvia | 1 | -- | 1 | 1 | 1 | 1 | 2 | One S. American
| | | | | | | | species
Vireo | 1 | 1 | -- | 1 | 1 | -- | 4 | Five species migrate
| | | | | | | | to Cuba
_Laletes_ | -- | -- | -- | 1 | -- | -- | 1 |
_Phoenicomanes_| -- | -- | -- | 1 | -- | -- | 1 |
| | | | | | | |
CORVIDÆ. | | | | | | | |
Corvus | 1 | -- | 1a | 1 | 1a | -- | 3 |
Cyanocorax | -- | -- | -- | 1 | -- | -- | 1 | S. American species
| | | | | | | |
MNIOTILTIDÆ. | | | | | | | |
Perissoglossa | 1 | -- | 1 | -- | 1 | -- | 1 | N. American species
Dendroeca | 2 | 2 | 1 | 3 | 1 | 1 | 7 | Twelve sp. migrate
| | | | | | | | to W. I.
_Teretristis_ | 2 | -- | -- | -- | -- | -- | 2 |
| | | | | | | |
COEREBIDÆ. | | | | | | | |
Certhiola | -- | 1 | 1 | 1 | 2 | 2 | 7 | Dominica and
| | | | | | | | Martinique
_Glossiptila_ | -- | -- | -- | 1 | -- | -- | 1 |
Coereba | 1 | -- | -- | -- | -- | -- | 1 | S. American species
| | | | | | | |
AMPELIDÆ. | | | | | | | |
_Dulus_ | (?)| -- | 1 | (?)| (?)| (?)| 2 | One species locality
| | | | | | | | unknown
| | | | | | | |
HIRUNDINIDÆ. | | | | | | | |
Progne | -- | -- | 1 | 1 | 1 | -- | 1 |
Pterochelidon | 1 | -- | -- | 1 | 1 | -- | 1 |
Hirundo | 1 | -- | 1a | 1a | -- | -- | 2 | One S. American
| | | | | | | | species
| | | | | | | |
TANAGRIDÆ. | | | | | | | |
Euphonia | 1a | -- | 1a | 1 | 1 | 1 | 4 | St. Bartholom. &
| | | | | | | | Martinique
_Spindalis_ | 2 | 1 | 1 | 1 | 1 | -- | 5 |
_Phænicophilus_| -- | -- | 1 | -- | -- | -- | 1 |
Saltator | -- | -- | -- | -- | -- | 1 | 1 | Guadeloupe and St.
| | | | | | | | Lucia
| | | | | | | |
FRINGILLIDÆ. | | | | | | | |
_Loxigilla_ | -- | -- | 1 | 1 | -- | 1 | 3 | Martinique and
| | | | | | | | Dominica
_Melopyrrha_ | 1 | -- | -- | -- | -- | -- | 1 |
Sycalis | -- | -- | -- | 1 | -- | -- | 1 | S. American species
Phonipara | 3 | -- | 3 | 3 | 2 | -- | 4 | One S. American
| | | | | | | | species
Chrysomitris | -- | -- | 1 | -- | -- | -- | 1 |
| | | | | | | |
ICTERIDÆ. | | | | | | | |
Icterus | 1 | -- | 1 | 1 | 2 | 2 | 6 |
Agelæus | 2 | -- | -- | -- | 1 | -- | 3 |
Sturnella | 1 | -- | -- | -- | -- | -- | 1 | Mexican species
_Nesopsar_ | -- | -- | -- | 1 | -- | -- | 1 |
Scolecophagus | 1 | -- | -- | -- | -- | -- | 1 |
Quiscalus | -- | -- | 1 | 1 | 2 | 2 | 4 | St. Lucia,
| | | | | | | | Martinique and
| | | | | | | | Barbadoes
| | | | | | | |
TYRANNIDÆ. | | | | | | | |
Elainea | -- | -- | -- | 2 | -- | 1 | 3 |
Pitangus | 1a | -- | -- | 1a | 1 | -- | 2 |
Contopus | -- | -- | -- | 1 | -- | 1 | 2 | St. Lucia
Myiarchus | 2 | -- | 1 | 3 | 1 | 1b | 7 | One S. American
| | | | | | | | species (b)
_Blacicus_ | 1a | -- | 1a | 1 | -- | -- | 2 |
Tyrannus | 2 | -- | -- | 1b | 1b | 2b | 3 | One sp. in Cen.
| | | | | | | | America (b)
| | | | | | | |
COTINGIDÆ. | | | | | | | |
Hadrostomus | -- | -- | -- | 1 | -- | -- | 1 |
| | | | | | | |
PICIDÆ. | | | | | | | |
Campephilus | 1 | -- | -- | -- | -- | -- | 1 |
_Xiphidiopicus_| 1 | -- | -- | -- | -- | -- | 1 |
Melanerpes | -- | -- | -- | -- | 1 | -- | 1 |
Chloronerpes | -- | -- | 1 | -- | -- | -- | 1 |
Centurus | 1 | -- | 1 | 1 | -- | -- | 3 |
Colaptes | 2 | -- | -- | -- | -- | -- | 2 |
_Nesoceleus_ | 1 | -- | -- | -- | -- | -- | 1 |
_Picumnus_ | -- | -- | ?1 | -- | -- | -- | 1 |
| | | | | | | |
CUCULIDÆ. | | | | | | | |
_Saurothera_ | 1 | -- | 1 | 1 | 1 | -- | 4 |
_Hyetornis_ | -- | -- | 1 | 1 | -- | -- | 2 |
Coccygus | 1 | -- | 2 | 1 | 1 | 1 | 3 | Dominica, St. Lucia,
| | | | | | | | all Neotropical
| | | | | | | | species
Crotophaga | 1 | -- | -- | 1 | 1 | 1 | 2 | N. & Cen. American
| | | | | | | | species
| | | | | | | |
TODIDÆ. | | | | | | | |
_Todus_ | 1 | -- | 1 | 2 | 1 | -- | 5 |
| | | | | | | |
TROGONIDÆ. | | | | | | | |
_Prionoteles_ | 1 | -- | -- | -- | -- | -- | 1 |
_Temnotrogon_ | -- | -- | 1 | -- | -- | -- | 1 |
| | | | | | | |
CAPRIMULGIDÆ. | | | | | | | |
Nyctibius | -- | -- | -- | 1 | -- | -- | 1 | Neotropical species
Chordeiles | -- | -- | -- | 1 | -- | -- | 1 |
Antrostomus | 2 | -- | -- | 1 | -- | 1 | 2 | One Neotropical
| | | | | | | | species
_Siphonorhis_ | -- | -- | -- | 1 | -- | -- | 1 |
Stenopsis | -- | -- | -- | -- | -- | 1 | 1 | Martinique
| | | | | | | | (S. America sp.)
| | | | | | | |
CYPSELIDÆ. | | | | | | | |
Cypselus | 1 | -- | -- | 1 | -- | -- | 1 |
Panyptila | -- | -- | 1 | -- | -- | -- | 1 | S. American species
Hemiprocne | -- | -- | 1 | 1 | -- | -- | 1 | Mexican species
Cypseloides | -- | -- | -- | 1 | -- | -- | 1 |
| | | | | | | |
TROCHILIDÆ. | | | | | | | |
Lampornis | -- | -- | 1a | 1 | 2a | 1a | 3 |
Doricha | -- | 2 | -- | -- | -- | -- | 2 |
_Eulampis_ | -- | -- | -- | -- | 1 | 2 | 2 | St. Croix, Dominica,
| | | | | | | | St. Lucia,
| | | | | | | | Martinique
_Aithurus_ | -- | -- | -- | 1 | -- | -- | 1 |
_Mellisuga_ | -- | -- | 1 | 1 | -- | -- | 1 |
Calypte | 1 | -- | -- | -- | -- | -- | 1 |
_Orthorhynchus_| -- | -- | -- | -- | 1 | 2 | 3 | Domin., Martini.,
| | | | | | | | St. Lucia
_Sporadinus_ | 1 | -- | 1 | -- | 1 | -- | 3 |
| | | | | | | |
CONURIDÆ. | | | | | | | |
Ara | 1 | -- | -- | -- | -- | -- | 1 | S. American species
Conurus | 1 | -- | -- | 1 | 1 | 1 | 1 | St. Thomas
| | | | | | | |
PSITTACIDÆ. | | | | | | | |
Chrysotis | 1 | -- | 1 | 2 | 1 | 3 | 8 |
| | | | | | | |
COLUMBIDÆ. | | | | | | | |
Columba | 1 | -- | 1 | 2 | 2 | 1 | 3 | One in Honduras
Chamæpelia | -- | -- | -- | 1 | 1 | 1 | 1 |
Zenaida | 1 | -- | 1 | 1 | 1 | 2 | 2 |
Leptoptila | -- | -- | -- | 1 | -- | -- | 1 |
Geotrygon | 2 | -- | 1 | 2 | 1 | 2 | 5 | St. Lucia,
| | | | | | | | Martinique, one
| | | | | | | | species Mexican
_Starnoenas_ | 1 | -- | -- | -- | -- | -- | 1 |
| | | | | | | |
TETRAONIDÆ. | | | | | | | |
Ortyx | 1 | -- | -- | -- | -- | -- | 1 |
| | | | | | | |
FALCONIDÆ. | | | | | | | |
Accipiter | 2 | -- | -- | -- | -- | -- | 2 |
Hypotriorchis | -- | -- | -- | 1 | -- | -- | 1 | Mexican species
Cerchneis | 2 | -- | 1 | -- | -- | 1 | 2 |
Cymindis | 1 | -- | -- | -- | -- | -- | 1 |
Polyborus | 1 | -- | -- | -- | -- | -- | 1 | Mexican species
| | | | | | | |
STRIGIDÆ. | | | | | | | |
Nyctalops | 1 | -- | -- | -- | -- | -- | 1 | S. American species
_Pseudoscops_ | -- | -- | -- | 1 | -- | -- | 1 |
_Gymnoglaux_ | 1 | -- | -- | -- | 1 | -- | 2 | St. Croix and St.
| | | | | | | | Thomas
Glaucidium | 1 | -- | -- | -- | -- | -- | 1 |
----------------+----+----+----+----+----+----+----+---------------------
{Number of families of resident land-birds in the Antilles 26
TOTALS { " " genera " " " 95
{ " " species " " " 203
{72}_Reptiles and Amphibia._--These classes not having been systematically
collected, and the numerous described genera not having undergone careful
revision, little trustworthy information can be derived from them. The
following enumeration of the chief groups hitherto noticed or described,
will, however, show very similar features to those presented by the
birds--a general relation to Neotropical forms, a more special relation to
those of Central America and Mexico, and a considerable number of peculiar
types.
Snakes.--_Arrhyton_ (Calamariidæ) from Cuba, _Hypsirhynchus_ from
Barbadoes, _Cryptodacus_ from Cuba, _Ialtris_ from Hayti, and _Coloragia_
from Cuba (all Colubridæ), have been described as genera peculiar to the
Antilles. _Phylodryas_ and _Dromicus_ (Colubridæ) are Antillean and
Neotropical; _Ahætulla_, (Dendrophidæ) has the same distribution but
extends to tropical Africa; _Epicrates_ and _Corallus_ (Pythonidæ) are
Neotropical and Antillean; while _Chilabothrus_ from Jamaica and _Ungalia_
from Cuba and Jamaica (both Pythonidæ) are found elsewhere only in Central
America and Mexico. There appear to be no Crotalidæ except an introduced
species of _Craspedocephalus_ in St. Lucia.
Lizards are more numerous. _Ameiva_ (Teidæ) is found all over America,
_Gerrhonotus_ (Zonuridæ) is Neotropical and occurs in Cuba; _Gymnopthalmus_
is South American and Antillean. Of Scincidæ seven genera are noted.
_Celestus_ (with 9 species) is peculiar to the Antilles; _Camilia_ (1
species) to Jamaica, _Panoplus_ (1 species) and _Embryopus_ (1 species) to
Hayti; _Diplogossus_ is Antillean and South American; while _Plestiodon_
and _Mabouya_ are cosmopolite. Of Geckotidæ there are four genera;
_Phyllodactylus_ and _Hemidactylus_ which are cosmopolite; _Sphærodactylus_
which is wholly American; and _Cubina_ found only in Martinique and Brazil.
Of Iguanidæ there are six genera; _Anolis_, which ranges all over America;
_Polychrus_, which is Neotropical; _Iguana_ and _Liocephalus_ which are
South American; _Tropedurus_ found in Cuba and Brazil; and _Cyclura_ only
known from Jamaica, Cuba, and Central America.
_Amphibia._--The genus _Trachycephalus_, belonging to the {73}Hylidæ or
tropical tree-frogs, is almost peculiar to the Antilles; Cuba, Hayti, and
Jamaica possessing seven species, while only one is recorded from South
America. Other genera are, _Peltaphryne_ (Bufonidæ) from Portorico;
_Phyllobates_ (Polypedatidæ) from Cuba; _Leiuperus_ (Ranidæ) from
Hayti,--all Neotropical. Of the Urodela, or tailed batrachians, no
representative occurs, although they are so characteristic a feature of the
Nearctic region.
_Fresh-water fish._--The same general remarks apply to these as to the
reptiles. Only one peculiar genus is noted--_Lebistes_, a form of
Cyprinodontidæ from Barbadoes; other genera of the same family being,
_Haplochilus_, _Rivulus_, and _Girardinus_, widely spread in the
Neotropical region; while _Gambusia_ is confined to Central America,
Mexico, and the Antilles. Four other families are represented; Siluridæ by
_Chætostomus_, found in Portorico and South America; Chromidæ by the South
American _Acara_; Mugillidæ by the Central American _Agonostoma_; and
Percidæ by the North American _Centrarchus_, of which a species is recorded
from Cuba.
_Insects._--The various West Indian islands have not been well explored
entomologically; one reason no doubt being, that their comparative poverty
renders them little attractive to the professional collector, while the
abounding riches of Central and South America lie so near at hand. We can,
therefore, hardly tell whether the comparative poverty, or even total
absence of some families while others seem fairly represented, is a real
phenomenon of distribution, or only dependent on imperfect knowledge.
Bearing this in mind, we proceed to give a sketch of what is known of the
chief groups of Lepidoptera and Coleoptera.
_Lepidoptera._--The Neotropical butterfly-fauna is but poorly represented,
the majority of the most remarkable types being entirely wanting; yet there
are a few peculiar and very characteristic forms which show great
isolation, while the majority of the species are peculiar. Four genera are
exclusively or characteristically Antillean,--_Calisto_ belonging to the
Satyridæ, with four species, of which one ranges to South Carolina;
_Clothilda_ {74}(Nymphalidæ) a fine genus which has 4 Antillean species and
2 in Central America; _Lucinia_ (Nymphalidæ) 2 species, confined to Jamaica
and Hayti; and _Kricogonia_ belonging to the Pieridæ, which has 2 West
Indian species, while 1 inhabits Mexico and Florida. Genera which show a
special relation to Central America are _Euptoieta_, _Eumæus_, and
_Nathalis_. Almost all the other genera are South American, the total
number recorded in each family as occurring in the West Indian islands,
being, 3 of Danaidæ; 1 of Heliconiidæ; 2 of Satyridæ; 18 of Nymphalidæ; 1
of Erycinidæ; 4 of Lycænidæ; 6 of Pieridæ; 1 of Papilionidæ, and 10 of
Hesperidæ. The genus _Papilio_ is represented by about 20 species, 2 of
which are North American, 4 South American, while the rest form little
characteristic groups allied to those of Central America. The most marked
feature seems to be the scarcity of Satyridæ and the almost total absence
of Erycinidæ, with a great deficiency in characteristic Neotropical forms
of Danaidæ and Nymphalidæ.
_Coleoptera._--Cicindelidæ and Carabidæ are very poorly represented, by a
few species of wide-spread groups, and hardly any peculiar genera. No
Lucanidæ are recorded. Of Cetoniidæ, _Gymnetis_ only appears to be
represented. Buprestidæ seem to be more numerous; 15 genera being recorded,
but almost all of wide distribution. One only is
peculiar--_Tetragonoschoma_, found in Hayti; _Halecia_ is the only
exclusively South American genus; _Chalcophora_ is widely scattered over
the tropical regions but is absent from South America, yet it occurs in the
Nearctic region and extends to Jamaica and Guadeloupe. We now come to the
Longicorns, the only group of Coleoptera which seems to be well
represented, or which has been carefully collected. No less than 40 genera
are known from the West Indian islands, and 15 of these are peculiar.
Prionidæ are proportionately very numerous, there being 10 genera, 2 of
which are widely distributed in both South and North America, 1 is North
American, and 1 South American, while the following are
peculiar,--_Stenodontes_ (Hayti and Cuba); _Dendroblaptus_ (Cuba);
_Monodesmus_ (Cuba and Jamaica); _Prosternodes_ (Cuba); _Solenoptera_ and
_Elateropsis_, the two largest genera found in most of the {75}islands. Of
Cerambycidæ there are 16 genera, 2 of which range all over America, 4 are
Neotropical, 1 South American only, while the following are confined to the
islands,--_Merostenus_, _Pentomacrus_, and _Eburiola_ (Jamaica);
_Bromiades_ (Cuba); _Trichrous_, _Heterops_, and _Pæciloderma_ (Antilles).
One genus, _Smodicum_, is widely spread, having a species in Carolina, 1 in
South America, 1 in Hayti, and 1 in West Africa. Of Lamiidæ there are 14
genera, 8 of which are Neotropical, 1 common to Central America and Mexico,
1 to the United States and Cuba, while 2, _Proecha_ and _Phidola_, are
confined to Cuba. Several of the genera are curiously
distributed;--_Spalacopsis_ is South American, with 4 species in Cuba and
Tropical Africa; _Lagocheirus_ is Neotropical, with a species in Australia;
while _Leptostilus_ is characteristic of the Antilles and North America,
with a few species in South America, and one in New Zealand. These cases of
erratic distribution, so opposed to the general series of phenomena among
which they occur, must be held to be sufficiently explained by the great
antiquity of these groups and their former wide distribution. They may be
supposed to be the remnants of types, now dying out, which were once, like
_Callichroma_, _Clytus_, and many others, almost universally distributed.
All the peculiar Antillean genera of Cerambycidæ and Lamiidæ are allied to
Neotropical forms. The peculiar Prionidæ, however, are mostly allied to
Mexican and North American groups, and one, _Monodesmus_, belongs to a
group all the other genera of which inhabit the East Indies and South
Africa.
_Land-shells._--This subject has already been generally treated under the
Region, of which, in this class of animals, the Antilles form so important
a part. We must therefore now confine ourselves mainly to the internal
distribution of the genera, and to a few remarks on the general bearing of
the facts.
The excessive and altogether unexampled productiveness of the West Indian
islands in land-shells, may be traced to two main sets of causes. The first
and least known, consist of the peculiar influences and conditions which
render islands always more productive than continents. Whatever these
conditions {76}are, they will be more effective where the islands have been
long separated from the mainland, as is here undoubtedly the case. It seems
most probable that the great development of land-shells in islands, is due
to the absence or deficiency of the vertebrata, which on continents supply
a variety of species adapted to prey upon these molluscs. This view is
supported by the fact, that in such islands as have been united to a
continent at no very distant epoch, and still maintain a continental
variety of vertebrata, no such special development of land-shells has taken
place. If we compare the Philippine islands with the Sunda group, we find
the development of vertebrata and land-molluscs in inverse ratio to each
other. The same thing occurs if we compare New Zealand and Tasmania; and we
have a still more striking example in the Antillean group itself,
continental Trinidad having only 20 genera and 38 species, while the highly
insular Jamaica has about 30 genera and more than 500 species.
The other causes favourable to the increase and development of land-shells
are of a physical nature. A great extent of limestone-rock is one; and in
the larger West Indian islands we have a considerable proportion of the
surface consisting of this rock. But perhaps equally or more important, is
the character of the land surface, and the texture of the exposed rock
itself. A much broken surface, with numerous deep ravines, cutting up the
whole country into isolated valleys and ridges, seems very favourable to
the specialization of forms in this very sedentary class of animals.
Equally favourable is a honeycombed and highly-fissured rock-surface,
affording everywhere cracks and crannies for concealment. Now, taking
Jamaica as an example of the archipelago, we find all these conditions in a
wonderful degree. Over a large part of this island, a yard of level ground
can hardly be found; but ridges, precipices, ravines, and rock-bound
valleys, succeed each other over the whole country. At least five-sixths of
the entire surface is limestone, and under the influence of tropical rains
this rock is worn, fissured, and honeycombed, so as to afford ample shelter
and concealment for land-shells.
{77}It is probable that the three chief islands, Cuba, Jamaica and Hayti,
are nearly equally rich in land-shells; but the last is very much less
known, and therefore, perhaps, appears to be much poorer. Cuba has rather
more species than Jamaica; but while the former has only 1 peculiar genus
(_Diplopoma_), the latter has 3 (_Geomelania_, _Chittya_, and _Jamaicea_),
as well as two others only represented in the other islands by single
species. From Hayti, only about one-third as many species are known as from
the two former islands. It has no peculiar genera, but it has some forms in
common with Cuba and others with Jamaica, which show that those islands
have more connection with it, than with each other; just as we found to be
the case in birds. Portorico and the Virgin islands have still fewer
species than Hayti; and, as many of the genera common to the other three
islands are wanting, there is, no doubt, here a real deficiency. In the
islands farther south (Barbuda to Martinique) more Antillean genera
disappear or become very rare, while some continental forms take their
place. The islands from St. Lucia to Trinidad have a still more continental
character; the genus _Bulimus_, so largely developed on the continent, only
reaching St. Lucia. The Bahamas contain about 80 species of land-shells, of
which 25 are Antillean, the rest peculiar; all the genera being Antillean.
The affinity is chiefly with Hayti and Cuba, but closest with the latter
island.
In the West Indian islands as a whole, there are 11 peculiar genera; 9
operculate (_Geomelania_, _Chittya_, _Jamaicea_, _Licina_, _Choanopoma_,
_Ctenopoma_, _Diplopoma_, _Stoastoma_, _Lucidella_); and 2 inoperculate
(_Sagda_ and _Stenopus_), besides _Cyclostomus_, which belongs to the Old
World and is not found on the American continent. Mr. Bland considers, that
many of the Antillean land-shells exhibit decided African and Asiatic,
rather than South American affinities. A species of the Asiatic genus
_Diplommatina_ has been found in Trinidad, and an Indian species of _Ennea_
occurs in Grenada and St. Thomas; a clear indication that land-shells are
liable to be accidentally imported, and to become established in the less
productive islands.
Although these islands are so wonderfully rich even now, {78}there is good
reason to believe that many species have become extinct since the European
occupation of them. When small islands are much cultivated, many of these
molluscs which can only live under the shade of forests, are soon
extirpated. In St. Croix many species have become extinct at a
comparatively recent period, from the burning of forests; and as we know
that in all the islands many of the species are excessively local, being
often confined to single valleys or ridges, we may be sure that wherever
the native forests have disappeared before the hand of man, numbers of land
shells have disappeared with them. As some of the smaller islands have been
almost denuded of their wood, and in the larger ones extensive tracts have
been cleared for sugar cultivation, a very considerable number of species
have almost certainly been exterminated.
_General Conclusions as to the Past History of the West Indian
Islands._--The preceding sketch of the peculiarities of the animal life of
these islands, enables us to state, that it represents the remains of an
ancient fauna of decided Neotropical type, having on the whole most
resemblance to that which now inhabits the Mexican sub-region. The number
of peculiar genera in all classes of animals is so great in proportion to
those in common with the adjacent mainland, as to lead us to conclude that,
subsequent to the original separation from the Mexican area, a very large
tract of land existed, calculated to support a rich and varied fauna, and,
by the interaction of competing types, give rise to peculiar and specially
modified organisms. We have already shown that the outline of the present
islands and the depths of the surrounding seas, give indications of the
position and extent of this ancient land; which not improbably occupied the
space enclosed by uniting Western Cuba with Yucatan, and Jamaica with the
Mosquito Coast. This land must have stretched eastward to include Anguilla,
and probably northward to include the whole of the Bahamas. At one time it
perhaps extended southward so as to unite Hayti with northern Venezuela,
while Panama and Costa Pica were sunk beneath the Pacific. At this time the
Lesser Antilles had no existence.
The only large island of whose geology we have any detailed {79}account, is
Jamaica; and taking this as a type of what will probably be found in Cuba
and Hayti, we must place the continental period as having occurred after
the close of the Miocene, or during some part of the Pliocene epoch, since
a large portion of the surface of the former island consists of beds of
marine limestone from 2,000 to 3,000 thick, believed to be of Pliocene age.
After some time, the land between Hayti and South America subsided, and
still later that between Central America and Cuba with Jamaica; but a large
tract of land remained insulated, and no doubt supported a very much richer
and more varied fauna than now. We have evidence of this in extinct
Mammalia of large size, belonging to the peculiar South American family of
the chinchillas, which have been found in caves in the small islands of
Anguilla, and which, from the character of the land-shells associated with
them, are believed to be of Pliocene or Post-pliocene age. This discovery
is most interesting, and gives promise of very valuable results from the
exploration of the numerous caverns that undoubtedly exist in the abundant
limestone strata of the larger islands. This extensive Antillean land,
after long continuing undivided, was at length broken up by subsidence into
several islands; but as this alone would not account for the almost
complete annihilation of the mammalian fauna, it seems probable that the
subsidence was continued much farther, so as greatly to reduce the size and
increase the number of the islands. This is indicated, by the extensive
alluvial plains in Cuba and Hayti, and to a less extent in Jamaica; and by
elevated beds of Post-pliocene marls in the latter island.
The series of changes now suggested, will account for all the main features
of the Antillean fauna in its relations to that of the American continent.
There remains the affinity with Madagascar, indicated by _Solenodon_, and a
few cases of African and Asiatic affinity in insects and land-shells; but
these are far too scanty to call for any attempt at special explanation.
Such cases of remote affinity and discontinuous distribution, occur in all
the regions, and in almost every group of animals; and we look upon them
almost all, as cases of survival, under favourable {80}conditions, of once
wide-spread groups. If no wild species of the genus _Equus_ were now to be
found, except in South Africa (where they are still most abundant), and in
South Temperate America, where their fossil remains show us they did exist
not very long ago, what a strong fact it would have appeared for the
advocates of continental extensions! Yet it would have been due to no
former union of the great southern continents, but to the former extensive
range of the family or the genus to which the two isolated remnants
belonged. And if such an explanation will apply to the higher vertebrata,
it is still more likely to be applicable to similar cases occurring among
insects or mollusca, the genera of which we have every reason to believe to
be usually much older than those of vertebrates. It is in these classes
that examples of widely scattered allied species most frequently occur; and
the facility with which they are diffused under favourable conditions,
renders any other explanation than that here given altogether superfluous.
The _Solenodon_ is a member of an order of Mammalia of low type
(Insectivora) once very extensive and wide-spread, but which has begun to
die out, and which has left a number of curious and isolated forms thinly
scattered over three-fourths of the globe. The occurrence, therefore, of an
isolated remnant of this order in the Antilles is not in itself remarkable;
and the fact that the remainder of the family to which the Antillean
species belong has found a refuge in Madagascar, where it has developed
into several distinct types, does not afford the least shred of argument on
which to found a supposed independent land connection between these two
sets of islands.
_Summary of the Past History of the Neotropical Region._
We have already discussed this subject, both in our account of extinct
animals, and in various parts of the present chapter. It is therefore only
necessary here, briefly to review and summarise the conclusions we have
arrived at.
The whole character of Neotropical zoology, whether as regards its
deficiencies or its specialities, points to a long continuance of isolation
from the rest of the world, with a few very distant {81}periods of union
with the northern continent. The latest important separation took place by
the submergence of parts of Nicaragua and Honduras, and this separation
probably continued throughout much of the Miocene and Pliocene periods; but
some time previous to the coming on of the glacial epoch, the union between
the two continents took place which has continued to our day. Earlier
submergences of the isthmus of Panama probably occurred, isolating Costa
Rica and Veragua, which then may have had a greater extension, and have
thus been able to develope their rich and peculiar fauna.
The isthmus of Tehuantepec, at the south of Mexico, may, probably, also
have been submerged; thus isolating Guatemala and Yucatan, and leading to
the specialization of some of the peculiar forms that now characterise
those countries and Mexico.
The West Indian Islands have been long isolated and have varied much in
extent. Originally, they probably formed part of Central America, and may
have been united with Yucatan and Honduras in one extensive tropical land.
But their separation from the continent took place at a remote period, and
they have since been broken up into numerous islands, which have probably
undergone much submergence in recent times. This has led to that poverty of
the higher forms of life, combined with the remarkable speciality, which
now characterises them; while their fauna still preserves a sufficient
resemblance to that of Central America to indicate its origin.
The great continent of South America, as far as we can judge from the
remarkable characteristics of its fauna and the vast depths of the oceans
east and west of it, has not during Tertiary, and probably not even during
Secondary times, been united with any other continent, except through the
intervention of North America. During some part of the Secondary epoch it
probably received the ancestral forms of its Edentates and Rodents, at a
time when these were among the highest types of Mammalia on the globe. It
appears to have remained long isolated, and to have already greatly
developed these groups of animals, before it received, in early Tertiary
times, the ancestors of its marmosets and monkeys, and, perhaps also, some
of its peculiar forms of {82}Carnivora. Later, it received its Camelidæ,
peccaries, mastodons, and large Carnivora; and later still, just before the
Glacial epoch, its deer, tapir, opossums, antelopes, and horses, the two
latter having since become extinct. All this time its surface was
undergoing important physical changes. What its earlier condition was we
cannot conjecture, but there are clear indications that it has been broken
up into at least three large masses, and probably a number of smaller ones;
and these have no doubt undergone successive elevations and subsidences, so
as at one time to reduce their area and separate them still more widely
from each other, and at another period to unite them into continental
masses. The richness and varied development of the old fauna of South
America, as still existing, proves, however, that the country has always
maintained an extensive area; and there is reason to believe that the last
great change has been a long continued and steady increase of its surface,
resulting in the formation of the vast alluvial plains of the Amazon,
Orinoko, and La Plata, and thus greatly favouring the production of that
wealth of specific forms, which distinguishes South America above all other
parts of our globe.
The southern temperate portion of the continent, has probably had a
considerable southward extension in late Tertiary times; and this, as well
as the comparatively recent elevation of the Andes, has given rise to some
degree of intermixture of two distinct faunas, with that proper to South
Temperate America itself. The most important of these, is the considerable
Australian element that appears in the insects, and even in the reptiles
and fresh-water fishes, of South Temperate America. These may be traced to
several causes. Icebergs and icefloes, and even solid fields of ice, may,
during the Glacial epoch, have afforded many opportunities for the passage
of the more cold-enduring groups; while the greater extension of southern
lands and islands during the warm periods--which there is reason to believe
prevailed in the southern as well as in the northern regions in Miocene
times--would afford facilities for the passage of the reptiles and insects
of more temperate zones. That no actual land-connection occurred, is proved
by the total absence {83}of interchange of the mammals or land-birds of the
two countries, no less than by the very fragmentary nature of the
resemblances that do exist. The northern element consists almost wholly of
insects; and is evidently due to the migration of arctic and north
temperate forms along the ridges and plateaus of the Andes; and most likely
occurred when these organisms were driven southward at successive cold or
Glacial periods.
A curious parallel exists between the past history and actual zoological
condition of South America and Africa. In both we see a very ancient
land-area extending into the South Temperate zone, isolated at a very early
period, and developing only a low grade of Mammalian life; chiefly
Edentates and Rodents on the one, Lemurs and Insectivora in the other.
Later we find an irruption into both of higher forms, including Quadrumana,
which soon acquired a large and special development in the tropical
portions of each country. Still later we have an irruption into both of
northern forms, which spread widely over the two regions, and having become
extinct in the land from whence they came, have been long held to be the
original denizens of their adopted country. Such are the various forms of
antelopes, the giraffe, the elephant, rhinoceros, and lion in Africa; while
in America we have deer and peccaries, the tapir, opossums, and the puma.
On the whole, we cannot but consider that the broad outlines of the
zoological history of the Neotropical region can be traced with some degree
of certainty; but, owing to the absence of information as to the most
important of the geological periods--the Miocene and Eocene--we have no
clue to the character of its early fauna, or to the land connections with
other countries, which may possibly have occurred in early Tertiary times.
{84}TABLES OF DISTRIBUTION.
In drawing up these tables, showing the distribution of the various classes
of animals in the Neotropical region, the following sources of information
have been relied on, in addition to the general treatises, monographs, and
catalogues used in the compilation of the Fourth Part of this work.
_Mammalia._--D'Orbigny, and Burmeister, for Brazil and La Plata; Darwin,
and Cunningham, for Temperate S. America; Tschudi, for Peru; Frazer, for
Ecuador; Salvin, for Guatemala; Frantzius, for Costa Rica; Sclater, for
Quadrumana N. of Panama; Gundlach, for Cuba; and papers by Dr. J. E. Gray,
and Mr. Tomes.
_Birds._--Sclater and Salvin's Nomenclator; Notes by Darwin, and
Cunningham; Gundlach, March, Bryant, Baird, Elliot, Newton, Semper, and
Sundevall, for various islands of the Antilles; and papers by Hudson,
Lawrence, Grayson, Abbott, Sclater, and Salvin.
{85}TABLE I.
_FAMILIES OF ANIMALS INHABITING THE NEOTROPICAL REGION._
EXPLANATION.
Names in _italics_ show the families which are peculiar to the region.
Names enclosed thus (......) indicate families which barely enter the
region, and are not considered properly to belong to it.
Numbers correspond with those of the series of families in Part IV.