Family106.—RHINIDÆ (1 Genus, 1 Species.)
"Sharks with depressed flat body and large expanded pectoral fins."
Distribution.—Temperate and tropical seas, from Britain to California and Australia.
Family107.—PRISTIOPHORIDÆ. (1 Genus, 4 Species.)
"Sharks with produced flat snout, armed with teeth on each edge."
Distribution.—Seas of Japan and Australia.
Sub-orderBatoidei. (Rays.)
Family108.—PRISTIDÆ. (1 Genus, 5 Species.)
"Rays with produced snout and lateral saw-like teeth."
Distribution.—Seas of tropical and sub-tropical regions.
Family109.—RHINOBATIDÆ. (3 Genera, 15 Species.)
"Rays with long and strong tail, having a caudal and two dorsal fins."
Distribution.—Tropical and sub-tropical seas.
Family110.—TORPEDINIDÆ. (6 Genera, 15 Species.)
"Rays with broad smooth disc, and an electric organ."
Distribution.—Tropical and temperate seas, from Britain to Tasmania.
Family111.—RAIIDÆ. (4 Genera, 29 Species.)
"Rays with broad rhombic disc and no serrated caudal spine."
Distribution.—All temperate and tropical seas. Several species ofRaiaare found on our coasts.
Family112.—TRYGONIDÆ (6 Genera, 43 Species.)
"Rays with the pectoral fins extending to end of snout."
Distribution.—Seas of all temperate and tropical regions, and rivers of Tropical America. A species ofTrygonhas occurred on our Southern coast.EllipesurusandTæniuraare found in the fresh waters of the interior of South America, while the latter genus occurs also in the Indian seas, but not in the Atlantic.
Family113.—MYLOBATIDÆ. (5 Genera, 22 Species.)
"Rays with very broad pectoral fins not extending to end of snout."
Distribution.—Temperate and tropical seas. A species ofMyliobatisis British, but most of the species and genera are confined to tropical seas.DicerobatisandCeratopteraare very large Rays, commonly called Sea-devils.
Sub-class V.—CYCLOSTOMATA.
"Cartilaginous fishes, with suctorial mouths and without lateral fins."
Family114.—PETROMYZONTIDÆ. (4 Genera, 12 Species.)
"Marine or fresh-water eel-like fishes, with suctorial mouths and without barbels."
Distribution.—Coasts and fresh waters of temperate regions of both hemispheres. Three species ofPetromyzon(Lampreys), are British.
Family115.—MYXINIDÆ. (2 Genera, 5 Species.)
"Marine eel-like fishes, with four pairs of barbels."
Distribution.—Seas of the temperate regions of both hemispheres.
Sub-classVI.—LEPTOCARDII.
Family116.—CIRRHOSTOMI. (1 Genus, 1 Species.)
"A small marine fish with no jaws or fins, and with rudimentary eyes."
Distribution.—The only species, the Lancelet (Amphioxus), is the lowest form of living vertebrate. It is found in the temperate regions of both hemispheres, and has occurred on our southern coast.
Remarks on the Distribution of Fishes.
Marine Fish.—There are about 80 families of marine fishes, and of these no less than 50 are universally, or almost universally, distributed over the seas and oceans of the globe. Of the remainder many are widely distributed, some species even ranging from the North Atlantic to Australia. Six families are confined to the Northern Seas, but four of these consist of single species only, the other two being the Discoboli (2 genera, 11 sp.), and the Accipenseridæ (2 genera and 20 sp.). Only one family (Acanthoclinidæ) is confined to the Southern oceans, and that consists of but a single species. Four families (Sternoptychidæ, Stomiatidæ, Alepocephalidæ and Halosauridæ) are confined to the Atlantic Ocean, while 13 are found only in the Pacific; and of the remainder several are more abundant in the Pacific than the Atlantic. Two families (Lycodidæ and Gadidæ) are found in the Arctic and Antarctic seas only, though thelatter family has a single species in the Indian seas. Among the curiosities of distribution are,—the extensive genusDiagramma, confined to the Pacific with the exception of one species in the Mediterranean; the single species constituting the family Lophotidæ, found only in the Mediterranean and Japan; the small family of Notacanthi, confined to Greenland, the Mediterranean, and West Australia; and the four families, Sternoptychidæ, Stomiatidæ, Alepocephalidæ, and Halosauridæ, which are believed to inhabit exclusively the depths of the ocean, and are therefore very rarely obtained.
Fresh-water Fish.—There are 36 families of fishes which inhabit fresh water exclusively, and 5 others, which are both marine and fresh-water. These present many interesting peculiarities of distribution. The Neotropical region is the richest in families, and probably also in genera and species. No less than 22 families inhabit it, and of these 6 are altogether peculiar. The Ethiopian and Nearctic regions each have 18 families, the former with 3, and the latter with 5 peculiar. Several isolated forms, requiring to be placed in distinct families, inhabit the great American lakes; and, no doubt, when the African lakes are equally well known, they will be found also to possess many peculiar forms. The Oriental region comes next, with 17 families, of which 3 are peculiar. The Palæarctic has 12, and the Australian 11 families, each with only 1 altogether peculiar to it.
If we take those regions which are sometimes supposed to be so nearly related that they should be combined, we shall find the fresh-water fishes in most cases markedly distinct. The Nearctic and Palæarctic regions, for example, together contain 20 families, but only 11 of these occur in both, and only 5 are exclusive inhabitants of these two regions. This shows an amount of diversity that would not, perhaps, be exhibited by any other class of animals. The Ethiopian and Oriental regions together possess 24 families, only 11 of which are found in both, and only 1 exclusively characteristic of the two. The Australian and Neotropical regions possess together 27 families, of which 7 are found in both, and 3 are exclusively characteristic of the two. This last fact is very interesting: the marine family ofTrachinidæ possesses a fresh-water genus,Aphritis, one species of which inhabits Tasmania, and two others Patagonia; the Haplochitonidæ (2 genera, 3 sp.) are found only in Tierra del Fuego, the Falkland Islands, and South Australia; and the Galaxidæ (1 genus, 12 sp.) inhabit the same regions, but extend to Chili, to New Zealand and to Queensland. We have here an illustration of that connection between South America and Australia which is so strongly manifested in plants, but of which there are only scattered indications in most classes of animals. The dividing line across the Malay Archipelago, separating the Oriental from the Australian regions, and which is so strikingly marked in mammalia and birds, is equally so in fresh-water fishes. No less than six families have their eastern limits in Java and Borneo; while the extensive family of Cyprinidæ has no less than 23 genera in Java and Borneo, but not a single species has been found in Celebes or the Moluccas.
The distribution of fresh-water fishes lends no support to the view that the peninsula of India belongs to the Ethiopian region. A large proportion of the Oriental families are common to the whole region; while there is hardly a single example, of a characteristic Ethiopian family or genus extending into the peninsula of India and no further.
Among the special peculiarities of distribution, is the curious fish, forming the family Comephoridæ, which is confined to Lake Baikal, among the mountains of Central Asia, 2,000 feet above the sea, and a thousand miles distant from the ocean; yet having its nearest allies in the exclusively oceanic family of the mackerels (Scomberidæ). The Characinidæ are confined to Africa and South America, distinct genera inhabiting each region. The Salmonidæ are confined to the two northern regions, except a single species of a peculiar genus in New Zealand. The genusOsteoglossumhas a species in South America, another in the Sunda Islands, and a third in Queensland; while the curious Sirenoidei are represented by single species of peculiar genera in Tropical America, Tropical Africa, and Tropical Australia.
Fossil Fishes.—Fishes have existed from a very remote era, and it is remarkable that the first whose remains have beendiscovered belong to the Ganoidei, a highly developed group which has continued to exist down to our times, and of which the sturgeon is the best known example. We may therefore be sure that the Upper Silurian rocks in which these are found, although so very far back in geological history, do not by any means lead us to the time when the primitive fish-type appeared upon the earth. In the Carboniferous and Permian formations numerous remains of fishes are found, allied to theLepidosteusor Gar-pike of North America. The next group in order of appearance, are the Plagiostomata, containing the existing Sharks and Rays. Traces of these are found in the highest Silurian beds, and become plentiful in the Devonian and Carboniferous formations and in all succeeding ages, being especially abundant in Cretaceous and Eocene strata. The Holocephali appear first in the Oolitic period, and are represented by the living Chimæridæ. The Dipnoi, to which belong theLepidosirenandCeratodus, are believed to have existed in the Triassic period, from the evidence of teeth almost identical with those of the existing Australian fish. All the ancient fossil fishes belong to the above-mentioned groups, and many of them have little resemblance to existing forms. The Teleostean fishes, which form the great bulk of those now living, cannot be traced back further than the Cretaceous period, while by far the larger number first appear in the Tertiary beds. The Salmonidæ, Scopelidæ, Percidæ, Clupeidæ, Scombresocidæ, Mugilidæ, and Siluridæ, or forms closely allied to them, are found in the Cretaceous formation. In the Eocene beds we first meet with Squammipennes, Cyprinidæ, Pleuronectidæ, Characinidæ, Murænidæ, Gadidæ, Pediculati, Syngnathidæ, and Hippocampidæ.
Most of these fossils represent marine fishes, those of fresh-water origin being rare, and of little importance as an aid in determining the causes of the distribution of living forms. To understand this we must look to the various changes of the land surface which have led to the existing distribution of all the higher vertebrates, and to those special means of dispersal which Mr. Darwin has shown to be possessed by all fresh-water productions.
THE DISTRIBUTION OF SOME OF THE MORE IMPORTANT FAMILIES AND GENERA OF INSECTS.
Although insects are, for the most part, truly terrestrial animals, and illustrate in a very striking manner the characteristic phenomena of distribution, it is impossible here to treat of them in much detail. This arises chiefly from their excessive numbers, but also from the minuteness and obscurity of many of the groups, and our imperfect knowledge of all but the European species. The number of described species of insects is uncertain, as no complete enumeration of them has ever been made; but it probably exceeds 100,000, and these may belong to somewhere about 10,000 genera—many times more than all vertebrate animals together. Of the eight Orders into which Insects are usually divided, only two—the Coleoptera and Lepidoptera—have been so thoroughly collected in all parts of the globe that they can be used, with any safety, to compare their distribution with that of vertebrate animals; and even of these it is only certain favourite groups which have been so collected. Among Lepidoptera, for example, although the extensive group of Butterflies may be said, in a general sense, to be thoroughly well known—every spot visited by civilized man having furnished its quota to our collections—yet the minute Tineidæ, or even the larger but obscure Noctuidæ, have scarcely been collected at all in tropical countries, and any attempt to study their geographical distribution would certainly lead to erroneous results. The same thing occurs, though perhaps in a less degree, among the Coleoptera. While the Carabidæ, Buprestidæ, andLongicorns of the Tropics, are almost as well known as those of the Temperate Zones, the Staphylinidæ, the smaller Elateridæ, and many other obscure and minute groups, are very imperfectly represented from extra-European countries. I therefore propose to examine with some care the distribution of the Butterflies, and the Sphingina among Lepidoptera, and the following large and well-known families of Coleoptera:—Cicindelidæ, Carabidæ, Lucanidæ, Cetoniidæ, Buprestidæ, and the three families of Longicorns. These families together contain over 30,000 species, classed in nearly 3,000 genera, and comprise a large proportion of the best known and most carefully studied groups. We may therefore consider, that a detailed examination of their distribution will lead us to results which cannot be invalidated by any number of isolated facts drawn from the less known members of the class.
Range of Insects in Time.—In considering how much weight is to be given to facts in insect distribution, and what interpretation is to be put upon the anomalies or exceptional cases that may be met with, it is important to have some idea of the antiquity of the existing groups, and of the rate at which the forms of insect life have undergone modification. The geological record, if imperfect in the case of the higher animals, is fragmentary in the extreme as regards indications of former insect life; yet the positive facts that it does disclose are of great interest, and have an important bearing on our subject. These facts and the conclusions they lead to have been discussed in our first volume (p. 166), and they must be carefully weighed in all cases of apparent conflict or incongruity between the distribution of insects and that of the higher animals.
Order—LEPIDOPTERA.
Sub-order—LepidopteraRhopalocera, orButterflies.
Family1.—DANAIDÆ. (24 Genera, 530 Species.)
The Danaidæ are now held to comprehend, not only the whole of the group so named by Doubleday, but a large portion of the Heliconidæ of that author. Their range is thus extended over the whole of the tropical regions. A few species spread northwards into the Palæarctic and Nearctic regions, but these are only stragglers, and hardly diminish the exclusively tropical character of the group. The more remarkable genera are,—Hestia(10 sp.), andIdeopsis(6 sp.), confined to the Malayan and Moluccan districts;Danais(50 sp.), which has the range of the whole family;Euplœa(140 sp.), confined to the Oriental and Australian regions, but especially abundant in the Malayan and Moluccan districts;Hamadryas(4 sp.), Australian region only. The remaining genera constitute the Danaioid Heliconidæ, and are strictly confined to Tropical America, except a few species which extend into the southern parts of the Nearctic region. The chief of these genera are:—
Ithomia(160 sp.),Melinæa(18 sp.),Napeogenes(20 sp.),Mechanitis(4 sp.),Ceratina(32 sp.),Dircenna(10 sp.), andLycorea(4 sp.). Florida, Louisiana, and Southern California, mark the northern extent of these insects.
Family2.—SATYRIDÆ. (60 Genera, 835 Species.)
This family has an absolutely universal distribution, extending even into the Arctic and Antarctic regions. Many of the genera are, however, restricted in their range.
Hætera,Lymanopoda,Calisto,Corades,Taygetis,Pronophila,Euptychia, and some allied forms (25 genera in all) are Neotropical, the last named extending north to Canada;Debis,Melanitis,MycalesisandYpthima, are mostly Oriental, but extending also into the Australian and the Ethiopian regions;Gnaphodes,Leptoneura, and a few other small genera, are exclusively Ethiopian;Xenica,Hypocista, andHeteronympha, are Australian;Erebia,Satyrus,Hipparchia,Cœnonympha, and allies, are mostly Palæarctic, but some species are Ethiopian, and others Nearctic;Chionabas, is characteristic of the whole Arctic regions, but is also found in Chili and the Western Himalayas. The peculiar genera in each region are,—Neotropical, 25; Australian, 7; Oriental, 11; Ethiopian, 5; Palæarctic, 3; Nearctic, 0.
Family3.—ELYMNIIDÆ. (1 Genus, 28 Species.)
The genusElymnias, which constitutes this family, is characteristic of the Malayan and Moluccan districts, with some species in Northern India and one in Ashanti. It thus agrees with several groups of Vertebrata, in showing the resemblanceof Malaya with West Africa independently of the Peninsula of India.
Family4. MORPHIDÆ. (10 Genera, 106 Species.)
The Morphidæ are a group of generally large-sized butterflies, especially characteristic of the Malayan and Moluccan districts, and of Tropical America; with a few species extending to the Himalayas on the west, and to Polynesia on the east. The genera are:—
Amathusia(6 sp.), Northern India to Java;Zeuxidia(9 sp.), the Malay district;Discophora(7 sp.), Northern India to Philippines, Java and Timor;Enispe(3 sp.), Northern India;Hyades(15 sp.), Moluccan and Polynesian districts, except one species in Java;Clerome(11 sp.), Northern India to Philippines and Celebes;Æmona(1 sp.), Sikhim;Hyantis(1 sp.), Waigiou;Thaumantis(10 sp.), Indo-Chinese and Malayan districts;Morpho(40 sp.), Neotropical region, Brazilian and Central American sub-regions.
Family5. BRASSOLIDÆ. (7 Genera, 62 Species.)
The Brassolidæ have the same distribution as the genusMorpho. The genera are:—
Brassolis(5 sp.);Opsiphanes(17 sp.);Dynastor(2 sp.);Penetes(1 sp.);Caligo(21 sp.);Narope(5 sp.); andDasyopthalma(3 sp.)
Family6.—ACRÆIDÆ. (1 Genus, 90 Species.)
The genusAcræais especially abundant in the Ethiopian region, which contains two-thirds of all the known species; 3 or 4 species only, range over the whole Oriental, and most of the Australian regions; while all the rest inhabit the same districts of the Neotropical region as the Brassolidæ.
Family7.—HELICONIDÆ. (2 Genera, 114 Species.)
The true Heliconidæ are very characteristic of the Neotropical region; one species only extending into the Southern States of North America as far as Florida. The genusHeliconius(83 sp.), has the range of the family; whileEueides(19 sp.), is confined to the Brazilian and Central American sub-regions.
Family8.—NYMPHALIDÆ. (113 Genera, 1490 Species.)
This is the largest and most universally distributed family of butterflies, and is well illustrated by our common Fritillaries,Tortoise-shell, Peacock, Painted Lady, and Purple Emperor butterflies. They are found wherever butterfly-life can exist, and some single species—like the Painted Lady (Pyrameis cardui)—range almost over the globe. A few of the more extensive and remarkable genera only, can be here noticed:—
Colænis,Agraulis,Eresia,Synchloe,Epicalia,Eunica,Eubagis,Catagramma,Callithea,Ageronia,Timetes,Heterochroa,Prepona,Hypna,Paphia, andSiderone, are wholly Neotropical, as well as many others which have a smaller number of species.Euryphene,Romaleosoma,Aterica, andHarma, are exclusively Ethiopian.Terinos,Athyma,Adolias, andTanæcia, are Oriental, but they mostly extend into the Moluccan region; the last however is strictly Malayan, andAdoliasonly reaches Celebes.Mynesalone, is exclusively Australian, butProthoeis almost so, having only one outlying species in Java.EurytelaandErgolisare confined to the Oriental and Ethiopian regions, but the latter reaches the Moluccas.Cethosia,Cirrhochroa,Messaras, andSymphædra, are both Oriental and Australian; whileJunonia,Cyrestis,Diadema,Neptis, andNymphalis, are common to the three tropical regions of the Eastern Hemisphere, the latter extending into the Mediterranean district, whileJunoniaoccurs also in South America and the Southern United States.
The most cosmopolitan genus isPyrameis, which has representatives in every region and every district.Apaturais found in all but the Ethiopian and the Australian, although it just enters the confines of the latter region in Celebes;Limenitisis abundant in the Oriental region, but extends eastward to Celebes and westward into Europe, North America, and even into South America.Argynnis,Melitæa, andVanessa, are almost confined to the Palæarctic and Nearctic regions; the former however occurs in the Himalayas and in the mountains of Java, and also in Chili and in Jamaica. Two genera—DicrorrhagiaandHelcyra—have both one species in North India and another in the island of Ceram. The number of genera peculiar to each region is as follows:—Neotropical, 50; Australian, 2; Oriental 15; Ethiopian, 14; Palæarctic, 1; Nearctic, 0.
Family9.—LIBYTHEIDÆ. (1 Genus, 10 Species.)
The genusLibythea, which constitutes this family, appears to have its head-quarters in the Oriental region, but extends on all sides in an erratic manner, into various remote and disconnected portions of the globe, as indicated above.
Family10.—NEMEOBIIDÆ. (12 Genera, 145 Species.)
This group has been separated from the Erycinidæ of the older authors, and contains all the non-American genera and species. Half the genera and nearly four-fifths of the species of this group are, however, Neotropical; one is European; two or three African; and twenty-six Oriental and Australian. The genera are:—
Nemeobius(1 sp.), Europe;Dodona(6 sp.), North India;Zemeros(2 sp.), North India and Malaya;Abisara(11 sp.), North India, Malayan and Moluccan districts, Madagascar and West Africa;Taxila(8 sp.), North India and Malaya;Dicallaneura(2 sp.), Moluccan district;Alesa(6 sp.),Eunogyra(2 sp.),Cremna(7 sp.),Bæotis(3 sp.), are all from the Brazilian sub-region;Eurybia(10 sp.),Mesosemia(80 sp.), inhabit both the Brazilian and Mexican sub-regions.
Family11.—EURYGONIDÆ. (2 Genera, 78 Species.)
This small family, separated from the true Erycinidæ by Mr. Bates, is confined to the tropical forest-districts of continental America. The genera are:—
Eurygona(71 sp.);Methonella(1 sp.); the latter found in Equatorial South America.
Family12.—ERYCINIDÆ. (59 Genera, 560 Species.)
This extensive family of small, but exquisitely beautiful butterflies, is especially characteristic of the virgin forests of the Neotropical region, only a few species of three genera extending into the Nearctic region. The more important genera, and those which have an exceptional distribution, can alone be here noticed.Charisextends from Brazil to New York;Apodemiafrom Brazil to California, Utah, and Oregon;Amarynthisinhabits the Brazilian and Antillean sub-regions;LepricornisandMetaphelesare small genera found only in the Mexican sub-region;Lymnas,Necyria,Ancyluris,Diorhina,Esthemopsis,Anteros,Emesis,Symmachia,Cricosoma,Calydna,Lemonias,Nymphidium,Theope, andAricorisare common to the Brazilian and Mexican sub-regions. All the other genera (40 in number) are only known from the Brazilian sub-region, and of these a considerable proportion are confined to the damp equatorial forests of the Amazon Valley.
Family13.—LYCÆNIDÆ. (39 Genera, 1,220 Species.)
The Lycænidæ—of the variety and beauty of which in tropical regions our own "Blues" and "Coppers" give but a faint idea—are a group of universal distribution. We shall therefore indicate those genera which are restricted to one or more regions, or are nearly cosmopolitan. The large genusPolyommatus(containing 325 species) has the same universal distribution as the entire family. Our common "Blues" well represent this genus.Lycæna(comprising the "Coppers") is more especially characteristic of the Palæarctic and Nearctic regions, but straggling species occur also in North India, South Africa, Chili, and New Zealand.Theclais especially characteristic of the Neotropical region, where there are about 370 species; in the Nearctic region, 36; in the Palæarctic 13; and in the Ethiopian 3.Miletus,Lucia,Hypolycæna,Myrina, andDeudorixare common to the three tropical regions of the Eastern Hemisphere—the Ethiopian, Oriental, and Australian.AphneusandIolausare common to the Ethiopian and Oriental regions, the latter extending to Celebes.Ialmenus,Pseudodipsas,Curetis, andAmblypodiaare common to the Oriental and Australian regions, but the first-named is found also in Madagascar.Zephyrusis found only in the Nearctic and Palæarctic,Eumæusin the Nearctic and Neotropical regions. The Nearctic region has one peculiar genus (Feniseca); the Palæarctic has two—ThestorandLæosopis; the Ethiopian has nine—Pentila,Liptana,D'Urbania,Axiocerces,Capys,Phytala,Epitola,Hewitsonia, andDeloneura; the Oriental has five—Allotinus,Ilerda,Poritia,Camena, andLiphyra; the Australian has three—Hypochrysops,Utica, andOgyris; and the Neotropical also three—Lamprospilus,Theorema, andTrichonis.
Family14.—PIERIDÆ. (35 Genera, 817 Species.)
The Pieridæ are distributed almost, if not quite, as widely over the globe as the last family, and we shall group the genera in the same manner.Pieris(130 sp.) is cosmopolitan;TeriasandCallidryasare found in all the four tropical regions, and as far north as Pennsylvania in the Nearctic region;Pontia,Tachyris,Eronia, andThestiasare common to the Ethiopian, Oriental, and Australian regions, the last-named, however, only extending as far as Timor;Coliasis pre-eminently Palæarctic and Nearctic, with a few Ethiopian species, one Indian, two in Chili, and one in the Sandwich Islands;Anthocharisis wholly Palæarctic and Nearctic;Mideahas two species Nearctic, and one in Japan;Gonepteryxis Palæarctic and Neotropical, extending into Texas;IdmaisandCallosuneare Ethiopian and Oriental;ThycaandIphiasare Oriental and Australian;Meganostomais Nearctic and Neotropical;NathalisandKricogoniaare Neotropical, ranging into Florida, Texas, and Colorado.
The peculiar genera are pretty equally distributed. The Neotropical region has ten, two being confined to Chili;EuterpeandLeptalisare the most remarkable, the latter containing a number of forms mimicking the Heliconidæ and Danaidæ. The Oriental region has two,PrionerisandDercas, the Australian one,Elodina; the Ethiopian two,TeracolusandPseudopontia; the Palæarctic two,LeucophasiaandZegris; the Nearctic one,Neophasia.