The Geographical Distribution of Animals, Volume 2

Chapter XXVI: Part IV: Geographical Zoology (8)

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The Anseres, or Swimmers, being truly aquatic birds, possess, as might be expected, a large number of cosmopolitan families and genera. No less than 5 out of the 8 families have a world-wide distribution, and the others are characteristic either of the North or the South Temperate zones. Hence arises a peculiarity of distribution to be found in no other order of birds; the Temperate being richer than the Tropical regions. The Nearctic and Palæarctic regions each have seven families of Anseres, two of which, the Colymbidæ and Alcidæ, are peculiar to them. The Ethiopian, Australian, and Neotropical regions, which all {368}extend into the South Temperate zone, have six families, with one peculiar to them; while the Oriental region, which is wholly tropical, possesses the five cosmopolitan families only.

There are about 78 genera and 552 species of Anseres, giving 69 species to a family, a high number compared with the Waders, and due to there being only one very small family, the Colymbidæ. The distribution of the Anseres, being more determined by temperature than by barriers, the great regions which are so well indicated by the genera and families of most other orders of birds, hardly limit these, except in the case of the genera of Anatidæ.

_Order X.--STRUTHIONES._

FAMILY 126.--STRUTHIONIDÆ. (2 Genera, 4 Species.)

The Ostriches consist of two genera, sometimes formed into distinct families. _Struthio_ (2 sp.) inhabits the desert regions of North, East, and South Africa, as well as Arabia and Syria. It therefore just enters the Palæarctic region. _Rhea_ (3 sp.) inhabits Temperate South America, from Patagonia to the confines of Brazil.

FAMILY 127.--CASUARIIDÆ. (2 Genera, 11 Species.)

The Cassowaries and Emeus are confined to the Australian region. The Emeus, _Dromæus_ (2 sp.), are found only on the {369}main-land of Australia (Plate XII. Vol. I. p. 441). _Casuarius_ (9 sp.) inhabits the islands from Ceram to New Britain, with one species in North Australia; it is most abundant in the Papuan Islands.

FAMILY 128.--APTERYGIDÆ. (1 Genus, 4 Species.)

The species of _Apteryx_ are entirely confined to the two larger islands of New Zealand. They are supposed to have some remote affinity with _Ocydromus_, a genus of Rails peculiar to Australia and New Zealand; but they undoubtedly form one of the most remarkable groups of living birds (Plate XIII. Vol. I. p. 445).

_Struthious Birds recently extinct._

A number of sub-fossil remains of birds, mostly large and some of gigantic size, having affinities to the _Apteryx_ and, less closely, to the Cassowaries, have been discovered in New Zealand. These are all classed by Professor Owen in the genus _Dinornis_ and family _Dinornithidæ_; but Dr. Haast, from the study of the rich collections in the Canterbury (New Zealand) Museum, is convinced that they belong to two distinct families and several genera. His arrangement is as follows. (See _Ibis_, 1874, p. 209).

FAMILY 129.--DINORNITHIDÆ. (2 Genera, 7 Species.)

_Dinornis_ (5 sp.); _Meionornis_ (2 sp.).

These had no hind toe, and include the largest species. Professor Newton thinks that they were absolutely wingless, being the only birds in which the fore limbs are entirely wanting.

{370}FAMILY 130.--PALAPTERYGIDÆ. (2 Genera, 4 Species.)

_Palapteryx_ (2 sp.); _Euryapteryx_ (2 sp.).

These had a well-developed hind toe, and rudimentary wings.

FAMILY 131.--ÆPYORNITHIDÆ. (1 Genus, 3 Species.)

A gigantic Struthious bird (_Æpyornis_), belonging to a distinct family, inhabited Madagascar.

It was first made known by its enormous eggs, eight times the bulk of those of the ostrich, which were found in a sub-fossil condition. Considerable portions of skeletons have since been discovered, showing that these huge birds formed an altogether peculiar family of the order.

_General Remarks on the Distribution of the Struthiones._

With the exception of the Ostrich, which has spread northward into the Palæarctic region, the Struthious birds, living and extinct, are confined to the Southern hemisphere, each continent having its peculiar forms. It is a remarkable fact that the two most nearly allied genera, _Struthio_ and _Rhea_, should be found in Africa and South Temperate America respectively. Equally remarkable is the development of these large forms of wingless birds in Australia and the adjacent islands, and especially in New Zealand, where we have evidence which renders it probable that about 20 species recently coexisted. This points to the conclusion that New Zealand must, not long since, have formed a much more extensive land, and that the diminution of its area by subsidence has been one of the causes--and perhaps the main one--in bringing about the extinction of many of the larger species of these wingless birds.

The wide distribution of the Struthiones may, as we have already suggested (Vol. I., p. 287.), be best explained, by supposing them to represent a very ancient type of bird, developed at a time when the more specialized carnivorous mammalia had {371}not come into existence, and preserved only in those areas which were long free from the incursions of such dangerous enemies. The discovery of Struthious remains in Europe in the Lower Eocene only, supports this view; for at this time carnivora were few and of generalized type, and had probably not acquired sufficient speed and activity to enable them to exterminate powerful and quick-running terrestrial birds. It is, however, at a much more remote epoch that we may expect to find the remains of the earlier forms of this group; while these Eocene birds may perhaps represent that ancestral wide-spread type which, when isolated in remoter continents and islands, became modified into the American and African ostriches, the Emeus and Cassowaries of Australia, the _Dinornis_ and _Æpyornis_ of New Zealand.

{372}CHAPTER XIX.

THE DISTRIBUTION OF THE FAMILIES AND GENERA OF REPTILES AND AMPHIBIA.

REPTILIA.

_Order I.--OPHIDIA._

FAMILY 1.--TYPHLOPIDÆ.--(4 Genera, 70 Species.)

The Typhlopidæ, or Blind Burrowing Snakes, are widely scattered over the warmer regions of the earth, but are most abundant in the Oriental and Australian regions, and least so in the Neotropical. They are absent from the Nearctic region; and in the Palæarctic are found only in South-eastern Europe and Japan.

The most extensive genus is _Typhlops_, comprising over 60 species, and having a range almost as extensive as the entire family. The other well characterised genera are:--

_Typhlina_ (1 sp.), ranging from Penang to Java and Hong Kong; _Typhline_ (1 sp.), the Cape of Good Hope; _Dibamus_ (1 sp.), New Guinea.

{373}FAMILY 2.--TORTRICIDÆ. (3 Genera, 5 Species.)

The Tortricidæ, or Short-tailed Burrowing Snakes, are a small family, one portion of which ranges from India to Cambodja, and through the Malay islands as far as Celebes and Timor; these form the genus _Cylindrophis_. Another portion inhabits America, and consists of:--

_Charina_ (1 sp.), found in California and British Columbia; and _Tortrix_ (1 sp.), in Tropical America.

We have here a case of discontinuous distribution, indicating, either very imperfect knowledge of the group, or that it is the remnant of a once extensive family, on the road to extinction.

FAMILY 3.--XENOPELTIDÆ. (1 Genus, 1 Species.)

The curious nocturnal carnivorous Snake, forming the genus _Xenopeltis_, and the sole representative of this family, ranges from Penang to Cambodja, and through the Malay Islands to Celebes.

FAMILY 4.--UROPELTIDÆ. (5 Genera, 18 Species.)

{374}The Uropeltidæ, or Rough-tailed Burrowing Snakes, are strictly confined to Ceylon and the adjacent parts of Southern India, and would almost alone serve to mark out our second Oriental sub-region. The genera are:--

_Rhinophis_ (7 sp.), Ceylon; _Uropeltis_ (1 sp.), Ceylon; _Silybura_ (8 sp.), Anamally Hills and Neilgherries; _Plecturus_ (3 sp.), Neilgherries and Madras; and _Melanophidium_ (1 sp.), the Wynand.

FAMILY 5.--CALAMARIIDÆ. (32 Genera, 75 Species.)

The Calamariidæ, or Dwarf Ground Snakes, are found in all warm parts of the globe, extending north into the United States as far as British Columbia and Lake Superior; but they are absent from the Palæarctic region, with the exception of a species found in Persia. The species are in a very confused state. The best characterised genera are the following:--

_Calamaria_ (20 sp.), Persia, India to Java and the Philippine Islands, Celebes, and New Guinea; _Rhabdosoma_ (18 sp.), Mexico and South America, and also the Malay Islands as far east as Amboyna, Timor, and New Guinea; _Typhlocalamus_ (1 sp.), Borneo; _Macrocalamus_ (1 sp.), India; _Aspidura_ (3 sp.), India and Ceylon; _Haplocerus_ (1 sp.), Ceylon; _Streptophorus_ (3 sp.), Central and South America;--with a host of others of less importance or ill-defined.

FAMILY 6.--OLIGODONTIDÆ. (4 Genera, 40 Species.)

{375}The Oligodontidæ are a small family of Ground Snakes which have been separated from the Calamariidæ, and, with the exception of a few species, are confined to the Oriental region. The best characterised genera are:--

_Oligodon_ (12 sp.), India, Ceylon, and Philippines; and, _Simotes_ (24 sp.), India to China and Borneo. In addition to these, _Achalinus_ is founded on a single species from Japan; and _Teleolepis_ consists of three species from North and South America.

FAMILY 7.--COLUBRIDÆ. (50 Genera, 270 Species.)

The Colubrine Snakes are universally distributed over the globe, and they reach the extreme northern limits of the order. They are, however, almost absent from Australia, being there represented only by a few species of _Tropidonotus_ and _Coronella_ in the northern and eastern districts. This great family consists of four divisions or sub-families: the Coronellinæ (20 genera, 100 species), the Colubrinæ (16 genera, 70 species), the Dryadinæ (7 genera, 50 species), and the Natricinæ (7 genera, 50 species). The more important genera of Colubridæ are the following:--

_Ablabes_, _Coronella_, _Ptyas_, _Coluber_, and _Tropidonotus_--all have a very wide distribution, but the two last are absent from South America, although _Tropidonotus_ reaches Guatemala; _Tomodon_, _Xenodon_, _Liopis_, _Stenorhina_, _Erythrolampus_, _Elapochrus_, _Callirhinus_, _Enophrys_, and _Dromicus_--are confined to the Neotropical region; _Hypsirhynchus_, _Cryptodacus_, _Jaltris_, and _Coloragia_, are confined to the West Indian Islands; _Chilomeniscus_, _Conophis_, _Pituophis_, and _Ischcognathus_, to North America, the latter going as far south as Guatemala; _Compsosoma_, _Zamenis_, _Zaocys_, _Atretium_, _Xenochrophys_, and _Herpetoreas_, are peculiarly Oriental, but _Zamenis_ extends into South Europe; {376}_Lytorhynchus_, _Rhamnophis_, _Herpetethiops_ and _Grayia_, are Ethiopian; _Rhinechis_ is peculiar to Europe; _Megablabes_ to Celebes, and _Styporhynchus_ to Gilolo; _Cyclophis_, is found in the Oriental region, Japan, and North America; _Spilotes_, in the Nearctic and Neotropical regions; _Xenelaphis_ in the Oriental, Ethiopian, and Palæarctic regions; _Philodryas_, _Heterodon_ and _Herpetodryas_ in America and Madagascar, the latter genus being also found in China.

FAMILY 8.--HOMALOPSIDÆ. (24 Genera, 50 Species.)

The Homalopsidæ, or Fresh-water Snakes, have been separated from the Hydridæ by Dr. Günther, and they include some groups which have been usually classed with the Natricinæ. They are especially characteristic of the Oriental region, where considerably more than half the genera and species are found; next comes the Neotropical region which has 6 species; while none of the other regions have more than 4 or 5. It is to be observed that the Ethiopian species occur in West Africa only, and mostly constitute peculiar genera, so that in this family the separation of the Ethiopian and Oriental regions is very well marked. The best characterised genera of the family are the following:--

_Cantoria_ (10 sp.), ranging from Europe to Japan, the Philippines, and Timor, with one species in Guinea; _Hypsirhina_ (6 sp.), Bengal, China, and Borneo; _Fordonia_ (3 sp.), Rangoon to Borneo and Timor; _Homalopsis_ (2 sp.), Cambodja to Java; _Cerberus_ (2 sp.), Ceylon and Siam, the Malay Islands, New Guinea, and North Australia; _Herpeton_ (1 sp.), Siam; _Ferania_ (1 sp.), Bengal to Penang; _Pythonopsis_ (1 sp.), Borneo; _Myron_ (2 sp.), India and North Australia; _Homalophis_ (1 sp.), Borneo; _Hipistes_ (1 sp.), Penang; _Xenodermus_ (1 sp.), Java; _Neusterophis_ and _Limnophis_, with one species each, are peculiar to West {377}Africa; _Helicops_ (2 sp.), North and South America; _Farancia_ and _Dimodes_, with one species each, are from New Orleans; and a few others imperfectly known from Tropical America.

FAMILY 9.--PSAMMOPHIDÆ. (5 Genera, 20 Species.)

The Psammophidæ, or Desert Snakes, are a small group characteristic of the Ethiopian and Oriental regions, but more abundant in the former. The distribution of the genera is as follows:--

_Psammophis_ (16 sp.), ranges from West Africa to Persia and Calcutta; _Coelopeltis_ (1 sp.), North and West Africa; _Mimophis_ (1 sp.), Madagascar; _Psammodynastes_ (2 sp.), Sikhim to Cochin China, Borneo and the Philippine Islands; and _Dromophis_ (1 sp.), Tropical Africa.

FAMILY 10.--RACHIODONTIDÆ. (1 Genus, 2 Species.)

The Rachiodontidæ are a small and very isolated group of snakes of doubtful affinities. The only genus, _Dasypeltis_ (2 sp.), is confined to West and South Africa.

{378}FAMILY 11.--DENDROPHIDÆ. (7 Genera, 35 Species.)

The Dendrophidæ, or Tree Snakes, are found in all the Tropical regions, but are most abundant in the Oriental. The genera are distributed as follows:--

_Dendrophis_ ranges from India and Ceylon to the Pelew Islands and North Australia, and has one species in West Africa; _Ahætulla_ is almost equally divided between Tropical Africa and Tropical America; _Gonyosoma_ ranges from Persia to Java and the Philippines; _Chrysopelea_ is found in India, Borneo, the Philippines, Amboyna, and Mysol; _Hapsidrophis_ and _Bucephalus_ are confined to Tropical Africa; and _Ithycyphus_ (1 sp.), is peculiar to Madagascar.

FAMILY 12.--DRYIOPHIDÆ. (5 Genera, 15 Species.)

The Dryiophidæ, or Whip Snakes, are a very well characterised family of slender, green-coloured, arboreal serpents, found in the three tropical regions but absent from Australia, although they just enter the Australian region in the island of Celebes. In Africa they are confined to the West Coast and Madagascar. The genera are:--

_Dryiophis_ (4 sp.), Tropical America and West Africa; _Tropidococcyx_ (1 sp.), Central India; _Tragops_ (4 sp.), Bengal to China, the Philippines, Java, and Celebes; _Passerita_ (2 sp.), Ceylon {379}and the Indian Peninsula; and _Langaha_ (2 sp.), confined to Madagascar.

FAMILY 13.--DIPSADIDÆ. (11 Genera, 45 Species.)

The Dipsadidæ, or Nocturnal Tree Snakes, are distinguished from the last family by their dark colours and nocturnal habits. They are about equally abundant in the Oriental and Neotropical regions, less so in the Ethiopian, while only a single species extends to North Australia. The following are the best known genera:--

_Dipsas_, comprising all the Oriental species with one in Asia-Minor, and a few from the Moluccas, New Guinea, North Australia, West Africa, and Tropical America; _Thamnodyastes_, _Tropidodipsas_, and several others, from Tropical America; _Dipsadoboa_, from West Africa and Tropical America; _Leptodeira_, from Tropical and South Africa, South America, and Mexico; and _Pythonodipsas_, from Central Africa.

FAMILY 14.--SCYTALIDÆ. (3 Genera, 10 Species.)

It is doubtful how far the three genera which constitute this family form a natural assemblage. We can therefore draw no safe conclusions from the peculiarity of their distribution--_Scytale_ and _Oxyrhopus_ being confined to Tropical America; while _Hologerrhum_ inhabits the Philippine Islands.

{380}FAMILY 15.--LYCODONTIDÆ. (11 Genera, 35 Species.)

The Lycodontidæ, or Fanged Ground Snakes, are confined to the Ethiopian and Oriental regions, over the whole of which they range, except that they are absent from Madagascar and extend eastward to New Guinea. The genera have often a limited distribution:--

_Lycodon_ ranges from India and Ceylon to China, the Philippines, and New Guinea; _Tetragonosoma_, the Malay Peninsula and Islands; _Leptorhytaon_ and _Ophites_, India; _Cercaspis_, Ceylon; and _Cyclocorus_, the Philippines. The African genera are _Boædon_, _Lycophidion_, _Holuropholis_, _Simocephalus_, and _Lamprophis_, the latter being found only in South Africa. The species are nearly equally abundant in both regions, but no genus is common to the two.

FAMILY 16.--AMBLYCEPHALIDÆ. (5 Genera, 12 Species.)

The Amblycephalidæ, or Blunt Heads, are very singularly distributed, being nearly equally divided between Tropical America and the eastern half of the Oriental region, as will be seen by the following statement of the distribution of the genera:--

_Amblycephalus_ (1 sp.), Malay Peninsula to Borneo and the Philippines; _Pareas_ (3 sp.), Assam, China, Java, and Borneo; {381}_Asthenodipsas_ (1 sp.), Malacca; _Leptognathus_ (6 sp.), Central and South America; and _Anoplodipsas_ (1 sp.), supposed to come from New Caledonia, and, if so, furnishing a link, though a very imperfect one, between the disconnected halves of the family.

FAMILY 17.--PYTHONIDÆ. (21 Genera, 46 Species.)

The Pythonidæ, comprising the Rock Snakes, Pythons, and Boas, are confined to the tropics, with the exception of one species in California. They are very abundant in the Neotropical region, where nearly half the known species occur; the Australian region comes next, while the Oriental is the least prolific in these large serpents. The genera which have been described are very numerous, but they are by no means well defined. The following are the most important:--

_Python_ is confined to the Oriental region; _Morelia_, _Liasis_, and _Nardoa_ are Australian and Papuan; _Enygrus_ is found in the Moluccas, New Guinea and the Fiji Islands; _Hortulia_ is African; _Sanzinia_ is peculiar to Madagascar; _Boa_, _Epicrates_, _Corallus_, _Ungalia_, and _Eunectes_ are Tropical American; _Chilabothrus_ is peculiar to Jamaica and Mexico; and _Lichanotus_ to California.

An extinct species belonging to this family has been found in the Brown-coal formation of Germany, of Miocene age.

FAMILY 18.--ERYCIDÆ. (3 Genera, 6 Species.)

{382}The Erycidæ, or Land Snakes, form a small but natural family, chiefly found in the desert zone on the confines of the Palæarctic, Oriental, and Ethiopian regions. They range from South Europe to West Africa and to Sikhim. The three genera are distributed as follows:--

_Cursoria_ (1 sp.), Afghanistan; _Gongylophis_ (1 sp.), India and Sikhim; _Eryx_ (4 sp.), has the range of the entire family.

FAMILY 19.--ACROCHORDIDÆ. (2 Genera, 3 Species)

The Acrochordidæ, or Wart Snakes, form a small and isolated group, found only in two sub-divisions of the Oriental region--the South Indian and the Malayan, and in New Guinea.

_Acrochordus_, inhabits Penang, Singapore, and Borneo; _Chersydrus_, Southern India and the Malay Peninsula, with a species recently discovered in New Guinea.

FAMILY 20.--ELAPIDÆ. (23 Genera, 100 Species.)

The Elapidæ, or Terrestrial venomous Colubrine Snakes, are an extensive group, spread over the tropics of the whole world, but especially abundant in Australia, where half the known species occur, some of them being the most deadly of venomous serpents. In the Oriental region they are also abundant, containing amongst other forms, the well-known Cobras. The American species are almost equally numerous, but they all belong to one {383}genus, and they are annulated with rings of various colours in a manner quite distinct from any other members of this family. The genera, which are all very distinct, are distributed as follows:--

_Diemenia_, _Acanthophis_, _Hoplocephalus_, _Brachiurophis_, _Tropidechis_, _Pseudechis_, _Cacophis_, _Pseudonaje_, _Denisonia_, and _Vermicella_, are Australian, the first two ranging to the Moluccas and New Guinea; _Ogmodon_ occurs in the Fiji Islands; _Naja_, _Bungarus_, _Ophiophagus_, _Pseudonaje_, _Xenurelaps_, _Doliophis_, _Megærophis_, and _Callophis_ are Oriental, one species of the latter genus being found in Japan, while an _Ophiophagus_ has been discovered in New Guinea; _Cyrtophis_, _Elapsoidea_, and _Poecilophis_ are African: _Elaps_ is American, ranging as far north as South Carolina, but not to the West Indian Islands.

FAMILY 21.--DENDRASPIDIDÆ. (1 Genus, 5 Species.)

The single genus _Dendraspis_, constituting the family, is confined to Tropical Africa.

FAMILY 22.--ATRACTASPIDIDÆ. (1 Genus, 4 Species.)

This small family, consisting of the genus _Atractaspis_, is also confined to Africa, but has hitherto only been found in the West and South.

{384}FAMILY 23.--HYDROPHIDÆ. (8 Genera, 50 Species.)

The Hydrophidæ, or Sea Snakes, are a group of small-sized marine serpents, abundant in the Indian and Australian seas, and extending as far west as Madagascar, and as far east as Panama. They are very poisonous, and it is probable that many species remain to be discovered. The genera are distributed as follows:--

_Hydrophis_ (37 sp.), ranging from India to Formosa and Australia; _Platurus_ (2 sp.), from the Bay of Bengal to New Guinea and New Zealand; _Aipysurus_ (3 sp.), Java to New Guinea and Australia; _Disteira_ (1 sp.), unknown locality; _Acalyptus_ (1 sp.), South-west Pacific; _Enhydrina_ (1 sp.), Bay of Bengal to New Guinea; _Pelamis_ (1 sp.), Madagascar to New Guinea, New Zealand, and Panama; _Emydocephalus_ (1 sp.), Australian Seas.

FAMILY 24.--CROTALIDÆ. (11 Genera, 40 Species.)

The Crotalidæ, or Pit Vipers, including the deadly Rattlesnakes, form a well-marked family of fanged serpents, whose distribution is very interesting. They abound most in the Oriental region, at least 5 of the genera and 20 species being found within its limits, yet they are quite unknown in the Ethiopian region--a parallel case to that of the Bears and Deer. A few species are peculiar to the eastern portion of the Palæarctic region, while {385}the Nearctic is actually richer than the Neotropical region both in genera and species. This would point to the conclusion, that the group originated in the Indo-Chinese sub-region and spread thence north-east to North America, and so onward to South America, which, having been the last to receive the group, has not had time to develop it largely, notwithstanding its extreme adaptability to Reptilian life. The genera are divided among the several regions as follows:--

_Craspedocephalus_ (7 sp.), Tropical America and the West Indian Islands; _Cenchris_, _Crotalophorus_, _Uropsophorus_, and _Crotalus_, inhabiting North America from Canada and British Columbia to Texas, one species (_Crotalus horridus_) extending into South America; _Trimeresurus_ (16 sp.), all India from Ceylon to Assam, Formosa, the Philippines and Celebes; _Peltopelor_ and _Hypnale_ (1 sp. each), peculiar to India; _Calloselasma_ (1 sp.), Siam; _Atropos_ (1 sp.), Java and Borneo; _Halys_ (3 sp.), peculiar to Tartary, Thibet, Japan, North China, and Formosa.

FAMILY 25.--VIPERIDÆ. (3 Genera, 22 Species.)

The Viperidæ, or True Vipers, are especially characteristic of the Palæarctic and Ethiopian regions, only one species being found over a large part of the Oriental region, and another reaching Central India. They are especially abundant in Africa, and the Palæarctic confines in South-western Asia. The common Viper ranges across the whole Palæarctic region from Portugal to Saghalien Island, reaching to 67° North Latitude, in Scandinavia, and to 58° in Central Siberia. The genera, according to Dr. Strauch's synopsis, are distributed as follows:--

_Vipera_ (17 sp.), which has the range of the family, extending over the whole of the Palæarctic and Ethiopian regions, except Madagascar, and as far as Ceylon, Siam, and Java, in the Oriental {386}region; _Echis_ (2 sp.), inhabiting North Africa to Persia and to Continental India; and _Atheris_ (3 sp.), confined to West Africa.

_Remarks on the General Distribution of Ophidia._

The Ophidia, being preeminently a Tropical order--rapidly diminishing in numbers as we go north in the Temperate Zone, and wholly ceasing long before we reach the Arctic Circle--we cannot expect the two Northern regions to exhibit any great variety or peculiarity. Yet in their warmer portions they are tolerably rich; for, of the 25 families of snakes, 6 are found in the Nearctic region, 10 in the Palæarctic, 13 in the Australian, 16 in the Neotropical, 17 in the Ethiopian, and no less than 22 in the Oriental, which last is thus seen to be by far the richest of the great regions in the variety of its forms of Ophidian life. The only regions that possess altogether peculiar families of this order, are the Ethiopian (3), and the Oriental (2); the usually rich and peculiar Neotropical region not possessing exclusively, any family of snakes; and what is still more remarkable, the Neotropical and Australian regions together, do not possess a family peculiar to them. Every family inhabiting these two regions is found also in the Oriental; and this fact, taken in connection with the superior richness of the latter region both in families and genera, would indicate that the Ophidia had their origin in the northern hemisphere of the Old World (the ancient Palæarctic region) whence they spread on all sides, in successive waves of migration, to the other regions. The distribution of the genera peculiar to, or highly characteristic of, the several regions is as follows:--

The Nearctic possesses 9; four of these belong to the Colubridæ, one to the Pythonidæ, and four to the Crotalidæ. The Palæarctic region has only 2 peculiar genera, belonging to the Colubridæ and Crotalidæ. The Ethiopian has 25, belonging to 11 families; four to Colubridæ, five to Lycodontidæ, and three to Elapidæ. The Oriental has no less than 50, belonging to 15 families; five are Colubridæ, five Uropeltidæ, twelve Homalopsidæ, six Lycodontidæ, three Amblycephalidæ, eight Elapidæ, and four {387}Crotalidæ. The Australian has 16, belonging to three families only; eleven being Elapidæ, and four Pythonidæ. The Neotropical has about 24, belonging to eight families; ten are Colubridæ, six Pythonidæ, and the rest Dipsadidæ, Scytalidæ, Amblycephalidæ, Elapidæ, and Crotalidæ.

We find then, that in the Ophidia, the regions adopted in this work are remarkably distinct; and that, in the case of the Oriental and Ethiopian, the difference is strongly marked, a very large number of the genera being confined to each region. It is interesting to observe, that in many cases the affinity seems to be rather between the West Coast of Africa and the Oriental region, than between the East Coast and the plains of India; thus the Homalopsidæ--a highly characteristic Oriental family--occur on the West Coast of Africa only; the Dryiophidæ, which range over the whole Oriental region, only occur in Madagascar and West Africa in the Ethiopian; the genus _Dipsas_ is found over all the Oriental region and again in West Africa. A cause for this peculiarity has been suggested in our sketch of the past history of the Ethiopian region, Vol. I. p. 288. In the Lycodontidæ, which are strictly confined to these two regions, the genera are all distinct, and the same is the case with the more widely distributed Elapidæ; and although a few desert forms, such as _Echis_ and the Erycidæ, are common to Africa and the dry plains of India, this is evidently due to favourable climatic conditions, and cannot neutralise the striking differences in the great mass of the family and generic forms which inhabit the two regions. The union of Madagascar with the South-western part of the Oriental region under the appellation Lemuria, finds no support in the distribution of Ophidia; which, however, strikingly accords with the views developed in the Third Part of this work, as to the great importance and high antiquity of the Euro-Asiatic continent, as the chief land-centre from which the higher organisms have spread over the globe.

_Fossil Ophidia._--The oldest known remains of Ophidia occur in the Eocene formation in the Isle of Sheppey; others are found in the Miocene (Brown Coal) of Germany, and in some Tertiary beds in the United States. Most of these appear to have been {388}large species belonging to the Pythonidæ, so that we are evidently still very far from knowing anything of the earliest forms of this order. In some of the later Tertiary deposits the poison fangs of venomous species have been found; also a Colubrine snake from the Upper Miocene of the South of France.

_Order II.--LACERTILIA._

FAMILY 26.--TROGONOPHIDÆ. (1 Genus, 1 Species.)

The single species of _Trogonophis_, forming this family, is found only in North Africa.

FAMILY 27.--CHIROTIDÆ. (1 Genus, 1 Species.)

_Chirotes_, the genus which constitutes this family, inhabits Mexico, and has also been found in Missouri, one of the Southern United States.

FAMILY 28.--AMPHISBÆNIDÆ. (1 Genus, 13 Species.)

{389}The Amphisbænidæ, which, in the opinion of Dr. Günther, are all comprised in the genus _Amphisbæna_, inhabit Spain and Asia Minor, North and Tropical Africa, South America as far as Buenos-Ayres and the West Indian Islands.

FAMILY 29.--LEPIDOSTERNIDÆ. (3 Genera, 6 Species.)

The small family of Lepidosternidæ has nearly the same distribution as the last, indicating a curious relationship between the Tropical parts of Africa and America. _Lepidosternon_ and _Cephalopeltis_ are American genera, while _Monotrophis_ is African.

FAMILY 30.--VARANIDÆ. (3 Genera, 30 Species.)

The Varanidæ, or Water Lizards, are most abundant in the Oriental region, whence they extend into the Austro-Malay Islands as far as New Guinea, and into Australia. Several species are found in Africa. _Psammosaurus_ (1 sp.), is found in North Africa and North-western India; _Monitor_ (18 sp.), has the range of the family; while _Hydrosaurus_ (8 sp.) ranges from Siam to the Philippines, New Guinea, and Australia.

{390}FAMILY 31.--HELODERMIDÆ. (1 Genus, 1 Species.)

The genus _Heloderma_, which constitutes this family, is found in Mexico.

FAMILY 32.--TEIDÆ. (12 Genera, 74 Species.)

The Teidæ, or Teguexins--a group of Lizards allied to the European Lacertidæ, but with differently formed superciliary scales--are highly characteristic of the Neotropical region, abounding almost everywhere from Patagonia to the Antilles and Mexico, and extending northwards to California on the west and to Pennsylvania on the east. The most extensive genus is _Ameiva_, containing nearly 60 species and having the range of the entire family; _Teius_ (3 sp.), inhabits Brazil and Mendoza; _Callopistes_ (2 sp.), Chili; _Centropyx_ (3 sp.), Paraguay to Alabama; _Dicrodon_ (Peru); _Monoplocus_ (Western Ecuador); with _Acrantus_, _Acanthopyga_, _Emminia_, _Crocodilurus_, _Custa_, and _Ada_, which each consist of a single species, and all inhabit Tropical America.

FAMILY 33.--LACERTIDÆ. (18 Genera, 80 Species.)

{391}The Lacertidæ, or Land Lizards, are small-sized, terrestrial, non-burrowing lizards, very characteristic of the Palæarctic region, which contains more than half the known species, and of the adjacent parts of the Oriental and Ethiopian regions, but extending also to South Africa, to Java, and even to Australia. The best-defined genera are the following:--

_Lacerta_ (10 sp.), ranging over all Central and South Europe to Poland, and farther north in Russia and Siberia, eastward to Persia, and southward to North and West Africa; _Zootoca_ (8 sp.), has nearly the same range in Europe as the last genus, but has representatives in Madeira, South Africa, and Australia; _Tachydromus_ (7 sp.) is widely scattered in Chinese Asia, Japan, Borneo, and West Africa; _Acanthodactylus_ (10 sp.) is most abundant in North Africa, but has a species in South Africa, and two in Central India; _Eremias_ (18 sp.) is found all over Africa, and also in the Crimea, Persia, Tartary and China; _Psammodromus_ (2 sp.), is confined to Spain, France, and Italy; _Ophiops_ (6 sp.), inhabits India, Persia, and Asia Minor to South Russia. Less strongly marked and perhaps less natural genera are the following:--

_Thetia_ (1 sp.), Algiers; _Teira_ (1 sp.), Madeira; _Nucras_ (4 sp.), Caucasus and South Africa; _Notopholis_ (4 sp.), South Europe and South Africa; _Algira_ (3 sp.), North and South Africa; _Scrapteira_ (1 sp.), Nubia; _Aspidorhinus_ (1 sp.), Caspian district; _Messalina_ (4 sp.), North Africa, Persia, and North-west India _Cabrita_ (1 sp.), Central India; _Pachyrhynchus_ (1 sp.), Benguela.

FAMILY 34.--ZONURIDÆ. (15 Genera, 52 Species.)

The Zonuridæ, or Land Lizards, characterised by a longitudinal fold of skin on each side of the body, have a very remarkable {392}distribution. Their head-quarters is the Ethiopian region, which contains more than half the known genera and species, most of which are found in South Africa and several in Madagascar. Next to Africa the largest number of genera and species are found in Mexico and Central America, with a few in the Antilles, South America, and California, and even as far north as British Columbia. Three of the genera form a distinct sub-group--the Glass Snakes,--the four species composing it being located in North Africa, North America, South-eastern Europe, and the Khasya Hills.

The prominent fact in the distribution of this family is, that the mass of the genera and species form two groups, one in South Africa, the other in Mexico,--countries between which it would be difficult to imagine any means of communication. We have here, probably, an example of a once much more extensive group, widely distributed over the globe, and which has continued to maintain itself only in those districts especially adapted to its peculiar type of organization. This must undoubtedly have been the case with the genus _Pseudopus_, whose two species now inhabit South-eastern Europe and the Khasya Hills in Assam respectively.

The genera are,--_Cordylus_, _Pseudocordylus_, _Platysaurus_, _Cordylosaurus_, _Pleurostrichus_, and _Saurophis_, confined to South Africa; _Zonurus_, South and East Africa and Madagascar; _Gerrhosaurus_, ranges over the whole Ethiopian region; _Cicigna_ is confined to Madagascar; _Gerrhonotus_ (22 sp.), ranges from British Columbia, California, and Texas, to Cuba and South America, but is most abundant in Mexico and Central America; _Abronia_ and _Barissia_, are two genera of doubtful distinctness, peculiar to Mexico; _Ophisaurus_ (the Glass Snake) is found in the Southern United States as far as Virginia; the allied genus _Hyalosaurus_ in North Africa; and _Pseudopus_, as above stated, in South-east Europe and the Khasya Hills.

{393}FAMILY 35.--CHALCIDÆ. (3 Genera, 8 Species.)

The Chalcidæ are a small group of Lizards characteristic of Tropical America, one species extending into the United States.

The genera are _Chalcis_ (6 sp.), ranging from Central America to Chili; two other species, which have been placed in distinct genera, inhabit North America and Peru.

FAMILY 36.--ANADIADÆ. (1 Genus, 1 Species.)

The single species of _Anadia_, constituting this family, inhabits Tropical America.

FAMILY 37.--CHIROCOLIDÆ. (1 Genus, 2 Species.)

The genus _Heterodactylus_, which constitutes this family, inhabits Brazil.

{394}FAMILY 38.--IPHISADÆ. (1 Genus, 1 Species.)

The single species of _Iphisa_, has been found only at Para in Equatorial America.

FAMILY 39.--CERCOSAURIDÆ. (1 Genus, 5 Species.)

The genus _Cercosaura_, is known only from Brazil and Ecuador.

FAMILY 40.--CHAMÆSAURIDÆ. (1 Genus, 1 Species.)

This family, consisting of a single species of the genus _Chamæsaura_, is confined to South Africa.

{395}FAMILY 41.--GYMNOPTHALMIDÆ . (5 Genera, 14 Species.)

The Gymnopthalmidæ, or Gape-eyed Scinks, so called from their rudimentary eyelids, form a small group, which is widely and somewhat erratically distributed, as will be seen by the following account of the distribution of the genera:--

_Lerista_ (1 sp.) and three other species for which Dr. Gray has established the genera--_Morethria_ (1 sp.), and _Menetia_ (2 sp.), are confined to Australia; _Cryptoblepharus_ (4 sp.), is found in West Australia, Timor, New Guinea, the Fiji Islands, and Mauritius; _Ablepharus_ (4 sp.), inhabits Eastern and South-eastern Europe, Persia, Siberia, West Africa, and the Bonin Islands; and _Gymnopthalmus_ (3 sp.), is found in Brazil and the West Indies.

FAMILY 42.--PYGOPODIDÆ. (2 Genera, 3 Species.)

This small family of two-legged Lizards, comprising the genera _Pygopus_ and _Delma_, is found only in Australia proper and Tasmania.

{396}FAMILY 43.--APRASIADÆ. (1 Genus, 2 Species.)

The genus _Aprasia_, constituting this family, is found in West and South Australia.

FAMILY 44.--LIALIDÆ. (1 Genus, 3 Species.)

This family is also confined to Australia, the single genus, _Lialis_, inhabiting the Western and Northern districts.

FAMILY 45.--SCINCIDÆ. (60 Genera, 300 Species.)

The Scincidæ, or Scinks, are an extensive family of smooth-scaled lizards, frequenting dry and stony places, and almost universally distributed over the globe, being only absent from the cold northern and southern zones. The family itself is a very natural one, and it contains many natural genera; but a large number have been established which probably require careful revision. The following include the more important and the best established groups:--

{397}_Scincus_ (2 sp.), North Africa and Arabia; _Hinulia_ (20 sp.), most of the Australian and Oriental regions; _Cyclodina_ (1 sp.), _Hombronia_ (1 sp.), and _Lygosomella_ (1 sp.), all from New Zealand; _Keneuxia_ (1 sp.), Philippines, Moluccas, and Papuan Islands; _Elania_ (1 sp.) New Guinea; _Carlia_ (2 sp.), North Australia and New Guinea; _Mocoa_ (16 sp.), Australia and New Zealand, with species in Borneo, West Africa, and Central America; _Lipinia_ (3 sp.), Philippine Islands and New Guinea; _Lygosoma_ (12 sp.), Australia, New Caledonia, Pelew and Philippine Islands; _Tetradactylus_ (1 sp.), _Hemierges_ (2 sp.), _Chelomeles_ (2 sp.), _Omolepida_ (1 sp.), _Lissolepis_ (1 sp.), _Siaphos_ (1 sp.), _Rhodona_ (3 sp.) _Anomalpus_ (1 sp.), _Soridia_ (2 sp.), and _Ophioscincus_ (1 sp.) all confined to Australia; _Cophoscincus_ (3 sp.), Philippine Islands, Celebes, and Queensland; _Plestiodon_ (18 sp.), China and Japan, Africa, and America as far north as Pennsylvania and Nebraska; _Eumeces_ (30 sp.), South Palæarctic, Oriental and Australian regions, to New Ireland and North Australia; _Mabouya_ (20 sp.), Oriental region, Austro-Malaya, North Australia, the Neotropical region, and to Lat. 42° 30' in North America; _Amphixestus_ (1 sp.), Borneo; _Hagria_ (1 sp.), and _Chiamela_ (1 sp.), India; _Senira_ (1 sp.), Philippine Islands; _Brachymeles_ (2 sp.), Philippine Islands and Australia; _Ophiodes_ (1 sp.), Brazil; _Anguis_ (3 sp.), West Palæarctic region and South Africa; _Tribolonotus_ (1 sp.), New Guinea; _Tropidophorus_ (2 sp.), Cochin-China and Philippine Islands; _Norbea_ (2 sp.), Borneo and Australia; _Trachydosaurus_ (1 sp.), Australia; Cyclodus (8 sp.), Australia, Aru Islands, and Ceram; _Silubosaurus_ (2 sp.), _Egerina_ (2 sp.), and _Tropidolepisma_ (6 sp.), all peculiar to Australia; _Heteropus_ (7 sp.), Australia, Austro-Malaya, and Bourbon; _Pygomeles_ (1 sp.), Madagascar; _Dasia_ (1 sp.), Malaya; _Euprepes_ (70 sp.), Ethiopian and Oriental regions, Austro-Malaya, South America (?); _Celestus_ (9 sp.), peculiar to the Antilles, except a species in Costa Rica; _Diploglossus_ (7 sp.), the Neotropical region;--with a number of other genera founded on single species from various parts of the world.

{398}FAMILY 46.--OPHIOMORIDÆ. (2 Genera, 2 Species.)

The snake-like Lizard constituting the genus _Ophiomorus_, is found in Southern Russia, Greece, and Algeria; while _Zygnopsis_ having four weak limbs, has been recently discovered by Mr. Blanford in South Persia. The family is therefore confined to our Mediterranean sub-region.

FAMILY 47.--SEPIDÆ. (7 Genera, 22 species.)

The Sepidæ, or Sand-Lizards, are a very natural group, almost confined to the Ethiopian region, but extending into the desert country on the borders of the Oriental region, and into the south of the Palæarctic region as far as Palestine, Madeira, Spain, Italy, and even the South of France. The genera are:--

_Seps_ (10 sp.), South Europe, Madeira, Teneriffe, Palestine, North Africa, South Africa and Madagascar; _Sphenops_ (2 sp.), North Africa, Syria, West Africa; _Scelotes_ (3 sp.), Angola to South Africa, Madagascar; _Thyrus_ (1 sp.), Bourbon and Mauritius; _Amphiglossus_ (1 sp.), Madagascar; _Sphenocephalus_ (1 sp.), Afghanistan; and _Sepsina_ (4 sp.), South-west Africa.

{399}FAMILY 48.--ACONTIADÆ. (3 Genera, 7 Species.)

This small family of snake-like Lizards has a very curious distribution, being found in South and West Africa, Madagascar, Ceylon, and Ternate in the Moluccas. _Acontias_ (4 sp.), is found in the four first-named localities; _Nessia_ (2 sp.), is confined to Ceylon; _Typhloscincus_ (1 sp.), to Ternate.

FAMILY 49.--GECKOTIDÆ. (50 Genera, 200 Species.)

The Geckoes, or Wall-Lizards, form an extensive family, of almost universal distribution in the warmer parts of the globe; and they must have some exceptional means of dispersal, since they are found in many of the most remote islands of the great oceans,--as the Galapagos, the Sandwich Islands, Tahiti, New Zealand, the Loo-Choo and the Seychelle Islands, the Nicobar Islands, Mauritius, Ascension, Madeira, and many others. The following are the larger and more important genera:--

_Oëdura_ (3 sp.), Australia; _Diplodactylus_ (8 sp)., Australia, South Africa, and California; _Phyllodactylus_ (8 sp.), widely scattered in Tropical America, California, Madagascar, and Queensland; _Hemidactylus_ (40 sp.), all tropical and warm countries; _Peropus_ (12 sp.), the Oriental region, Papuan Islands, Mauritius, and Brazil; _Pentadactylus_ (7 sp.), Oriental region and Australia; _Gecko_ (12 sp.), Oriental region to New Guinea and {400}North Australia; _Gehyra_ (5 sp.), Australia, New Guinea and Fiji Islands; _Tarentola_ (7 sp.), North Africa, North America, Madeira, Borneo, South Africa; _Phelsuma_ (6 sp.), Madagascar, Bourbon, and Andaman Islands; _Pachydactylus_ (5 sp.), South and West Africa, and Ascension Island; _Sphærodactylus_ (5 sp.), the Neotropical region; _Naultinus_, (6 sp.), New Zealand; _Goniodactylus_ (5 sp.), Australia, Timor, South America and Algiers; _Heteronota_ (4 sp.), Australia, Fiji Islands, New Guinea and Borneo; _Cubina_ (4 sp.), the Neotropical region; _Gymnodactylus_ (16 sp.), all warm countries except Australia; _Phyllurus_ (3 sp.), Australia; _Stenodactylus_ (4 sp.), North and West Africa, and Rio Grande in North America.

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The Geographical Distribution of Animals, Volume 2Chapter XXVI: Part IV: Geographical Zoology (8)

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