821 



FISH. 



FISH. 



822 



Barriers of land, as chains of mountains, determining the courses of 

 rivers, are often the boundaries between two distinct specific assem- 

 blages of fresh-water fish, and in like manner a very narrow strip of 

 land may divide two very distinct marine faunas. The distribution 

 of marine vegetables, affecting the distribution of numerous marine 

 Invertebrata which feed on those vegetables, and in their turn serve 

 to furnish food for fishes, will materially affect the distribution of 

 many species of the latter. So also will the presence of currents, and 

 even the agency of man, assisting often unintentionally in the con- 

 veyance of ova from one country to another. Distant regions, pre- 

 senting similar conditions, such as the arctic and antarctic seas, are 

 inhabited by species representative but not identical, and presenting 

 a general aspect very similar, depending on characters of form and 

 colour, &c. It ia probable also that the fishes inhabiting the greater 

 depths of tropical seas resemble those of temperate climes, and that 

 those of the latter in like manner approach arctic forms. 



A brief glance at the range and distribution of the principal genera 

 will best serve to illustrate the above positions. 



The lowest and most anomalous of all the species of fishes, the 

 Branchiottoma, is generally distributed through the seas of Europe. 

 Only one species is known, yet we cannot but hope that the researches 

 of the many active naturalists now occupied with the study of marine 

 zoology will bring to light forms connecting the Lancelet with other 

 genera. The Myxine, or Glutinous Hag, almost equally strange in form 

 and structure, is confined to the most northern and most southern 

 seas, and is replaced in the higher parts of the southern hemisphere 

 by the equally curious and nearly allied genus Heptatrema. The 

 Lampreys inhabit the fresh-waters of Europe and North America, 

 but the species in each are quite distinct. Lcpidosiren, the connecting 

 link between fishes and reptiles, so dubious in organisation that its 

 position ii still disputed, is an inhabitant of the west of Africa, and a 

 genus closely allied has been discovered by Dr. Peters on the eastern 

 coast of the same continent. 



The Rays and Sharks are universally distributed, but many of the 

 genera and species are very local and apparently regulated in their 

 range by climatal zones. The seas of Europe can boast of the greater 

 number, though fortunately the most formidable of the species are 

 exotics. The largest species, as the great Silachut maximua, the 

 Basking Shark, are harmless, and have their favourite habitats in the 

 temperate zone. Size among fishes does not appear to bear any 

 relation to latitude. Chimaera is northern and southern, extending 

 from the frigid zone. The Sclerodermi are for the most part southern 

 and tropical, especially the curious forms of Cestracion and Astracion, 

 Monacanthui inhabits the American and Chinese seas ; Triodon, the 

 Indian Ocean ; Tetrodon, Diadon, and Batista have wider ranges. 

 The typical genus of Pipe-Fishes (Syngnaihut), is cosmopolitan, and has 

 a very wide geographical distribution. Six species are found in the 

 British seas, two on the coast of the United States, and Mr. Jenyns 

 has described new forms from Valparaiso, Tahiti, and Patagonia. 

 Hippocampus is of the temperate zones of both hemispheres, and in 

 the tropical seas is replaced by Solenoiloma and Peyasus. The 

 Sturgeons inhabit the Western European seas, the Caspian, the Black 

 Sea, and the Mediterranean. Three species are North American. 



Of the Eels, Anyutlla, Conger, and Murcena are typical and cosmo- 

 politan. Gymnarchiu is Egyptian, Gymnotut (the Electrical Eel) South 

 American, both inhabitants of fresh-water. The osseous flat fishes are 

 very generally distributed ; the largest species are inhabitants of 

 northern geas. The Mediterranean boasts of many species of Pleu- 

 ronecta. Species of Sole are found in both northern and southern 

 hemispheres. The Gadidie are inhabitants of northern and temperate 

 seas, and certain species, as the Tusk, do not range farther southward 

 than Norway and Scotland. Ltpidotteus, one of the few remaining 

 genera of Sauroid fishes, which appear to have played a most im- 

 portant part in the waters of ancient geological epochs, is confined to 

 the rivers of America, and some allied forms to northern Africa. The 

 herring tribe, Clupeidce, baa a wide distribution, and forms of tbe 

 typical genus Ctupea are found in the southern as well as in the 

 northern hemisphere. The species however are locally distributed ; 

 thus the true Herring is unknown in the Mediterranean, where its 

 place is taken by the Sardine, and the herrings of the South American 

 coasts are quite distinct from those of the north. Even within very 

 limited areas, as in that of the British seas, the species have peculia- 

 rities of distribution, as we see in the prevalence of the herring, 

 properly so called, on the coasts of Scotland and in the Irish Sea, while 

 it is replaced by the Pilchard on the south-west coasts of England 

 and south of Ireland : the Whitebait is also a remarkable instance of 

 local distribution. itormyra, Esoccetnt, and Esox are the typical 

 forms of pikes ; the first is North African ; the flying fishes are 

 oceanic and Mediterranean, and the pikes proper are inhabitants 

 of the temperate zones. The restricted genus Esox is confined to 

 fresh water. 



The important family of Kalmonidce has its most valuable members 

 in northern regions, some with a wide range, the same species of trout 

 occurring in Lapland and in Switzerland. In North America the 

 Trout* are represented by very similar but distinct species. M'Clel- 

 land has described a true salmon from India inhabiting the tributaries 

 of the Oxus. Thin instance however does not affect the essentially 

 temperate and subarctic character of the distribution of iheSalmonuhc, 



for this Indian species was found at an elevation of 11,000 feet, 

 where we must expect to find temperate forms prevail. Jenyns has 

 made known a peculiar genus of Salmonidce, which he has named 

 Aplochiton, inhabiting the seas of the Falkland Islands and Tierra 

 del Fuego. ajore is a genus constituted by De Kay, and confined to 

 the United States. The Argentines are Mediterranean, and Stemoptyx 

 is oceanic. 



Among the most characteristic fishes of the fresh waters of tropical 

 countries are the Siluridce, which abound in the regions of Central 

 Asia, where almost all the species of the typical genus SUums occur. 

 A single oifset finds its way to Europe. Pimelodus and Ccdlichthys 

 are American genera of this family; the electrical Malapterurus, 

 North African ; Loricaria, South American. Equally interesting and 

 well marked in distribution is the fresh-water family Cyprinida. The 

 true Carps are characteristic of the Old World ; Vatastoma and 

 Anableps of the New World. 



Of the Acanthopterygious Fishes the genera Centrisciis and Fistu- 

 laria are, with the exception of a single Mediterranean species, 

 tropical. The genera of Labridce have well-marked provinces. Thus 

 the numerous species of Scarus are grouped together in tropical seas, 

 being replaced in temperate regions by Labrus&nd Crenilabrus. There 

 are offsets however of each. The frog-fishes Lophius and Chironectes 

 are chiefly represented in Africa and South America. A single 

 Lophius is a native of European seas. De Kay enumerates seven 

 Lop/tiadre as inhabitants of the United States, and Richardson has 

 described some Australian species. The Goby tribe prevails in Europe 

 and Asia. Some of the species of Gobiua are remarkable for the 

 depth at which they live. The Blennies are truly European, with 

 very few exceptions. The Gunnels are mostly of northern seas. 

 Some species of the Goby tribe inhabit fresh water, as the geuus 

 Tienioides, which is found in marshes in India. Comeptwus lives 

 in Lake Baikal, and one or two species of Gobius proper live in rivers. 



The Mugiloida are very generally extended. They have been said 

 to be absent from North America, but this is incorrect, four species 

 of Mugil inhabiting the United States. Atherina is also a cosmopo- 

 litan genus. 



The Labyrinthiform Pharyngeans are essentially tropical, being all 

 natives of the eastern regions of Asia. Their organisation is pecu- 

 liarly adapted to their climatal range. The Teuthyes are fishes of 

 warm climates, and many species inhabit the Australasian seas. The 

 Mackerel tribe includes a number of genera, which have very various 

 areas of distribution. Among them the Dolphins (Coryphcena) are 

 Mediterranean and oceanic ; the Dories (Zeus) mostly European ; 

 Vomer, exotic ; Notacanthus, arctic ; Lichia, Mediterranean. Scomber 

 and the allied typical genera of the tribe are mostly cosmopolitan. 

 The Chetodons are essentially equatorial. 



The family of Sparoidece gives the most prominent feature to the 

 ichthyology of the Mediterranean and seas of Southern Europe. 

 Payrus has a wide range, but chiefly through warm regions. The 

 Scienoidea;, very numerous in species, are mostly equatorial. The 

 important family of Triglidce, of which the Gurnard is the type, has 

 a very extensive distribution. The true Gurnards are mostly Euro- 

 pean ; Scorpcma ranges from Europe to Australia. PLatycephalus is 

 peculiarly Indian. Kebaates is a genus of the Old World, with one or 

 two exceptions. 



The Percidce, chief of the Acanthopterygious families, is partly 

 composed of marine and partly of fresh-water genera. The genus 

 Perca is characteristic of the northern temperate zone. Mesoprion, 

 Diacope, Plectropomut, and Serranus are cosmopolitan. Mullus and 

 Paralepis are European genera, llolocentris, Myripriitia, Priacanthus, 

 and Dtdes are represented in both hemispheres. Ambassia is an Indian 

 fresh-water genus. Percophis, Pinyuipet, Centrarchus, and Pomotis 

 are American. Beryx, Trachichtes, Helotes, Pelotea, and Chironeina 

 are Australian. 



Point Fishes.^In the study of extinct fishes the structure of the 

 scales is of first importance, and according to their particular cha- 

 racters the whole of the fossil species have been divided. M. Agassiz 

 makes four orders, each of which contains fishes having a cartilaginous 

 skeleton ; in each there are genera the species of which have 

 spinous rays in the dorsal fin, and other genera where all the rays of 

 the dorsal fin are soft. There are likewise in each order both apodal 

 and abdominal genera ; and in two of the orders there are in addition 

 certain species in which the ventral fins are thoracic, and others in 

 which they are jugular. These four orders are named by M. Agassiz 

 Placoides, Ganoides, Ctenoidts, and Cycloidei. 



The name Placoides (from irAa, a plate or slab) was applied to the 

 first of these orders on account of the irregularity which the solid tegu- 

 mentary parts present. They consist of masses of enamel, which are 

 often of considerable size, and sometimes minute. To this family 

 belong the Cestracionites, of which there is but one existing genus 

 (the genus Cestracion), the Squalidce, Raidte, and Cyclostomi. 



The second order, Ganoides (from yavbs, splendour), are distin- 

 guished by the angular form of the scales; these are composed of 

 layers of corneous or osseous substances, disposed one upon the 

 other and covered by a thick coat of enamel, and consequently 

 resemble teeth in their structure. This order contains the following 

 families : Lepidoidei, all the species of which are fossil ; the Sau- 

 roide, which are also fossil, with the exception of two genera, Lepieostcua 



