CHAPTER XX.

DISTRIBUTION OF PELAGIC FISHES 292

CHAPTER XXI.

THE FISHES OF THE DEEP SEA 296

Deep-sea fishes a recent discovery, 296--Physical conditions affecting these fishes, 297--Characteristics of Deep-sea fishes, 299--Their vertical and horizontal distribution, 304--List of Deep-sea fishes, 305.

SYSTEMATIC AND DESCRIPTIVE PART.

FIRST SUB-CLASS--PALÆICHTHYES.

PAGE FIRST ORDER--CHONDROPTERYGII 313

I. Plagiostomata 313

A. Selachoidei--Sharks 314

Families: Carchariidæ (Blue Shark, Tope, Hammerhead, Hound), 316--Lamnidæ (Porbeagle, Carcharodon, Fox-Shark, Basking-Shark), 319--Rhinodontidæ, 323--Notidanidæ, 324--Scylliidæ (Dog-fishes), 325--Hybodontidæ, 328--Cestraciontidæ (Port Jackson Shark), 328--Spinacidæ (Spiny Dogs, Greenland Shark), 330--Rhinidæ, 334--Pristiophoridæ, 335.

B. Batoidei--Rays 335

Families: Pristidæ (Saw-fishes), 336--Rhinobatidæ, 337--Torpedinidæ (Electric Rays), 338--Rajidæ (Rays and Skates), 340--Trygonidæ (Sting Rays), 342--Myliobatidæ (Eagle Rays), 344.

II. Holocephala 348

Family: Chimæridæ, 348.

SECOND ORDER--GANOIDEI 350

I. Placodermi 351

II. Acanthodini 355

III. Dipnoi 355

Families: Sirenidæ (Lepidosiren, Protopterus, Ceratodus), 355--Ctenododipteridæ, 359--Phaneropleuridæ, 360.

IV. Chondrostei 360

Families: Acipenseridæ (Sturgeons), 360--Polyodontidæ, 362.

V. Polypteroidei 363

Families: Polypteridæ, 364--Saurodipteridæ, 365--Coelacanthidæ, 365--Holoptychidæ, 365.

VI. Pycnodontoidei 366

Families: Pleurolepidæ, 366--Pycnodontidæ, 366.

VII. Lepidosteoidei 367

Families: Lepidosteidæ, 367--Sauridæ, 368--Stylodontidæ, 368--Sphærodontidæ, 368--Aspidorhynchidæ, 369--Palæoniscidæ, 369--Platysomidæ, 370.

VIII. Amioidei 370

Families: Caturidæ, 371--Leptolepidæ, 371--Amiidæ (Bow-fin), 371.

SECOND SUB-CLASS--TELEOSTEI.

FIRST ORDER--ACANTHOPTERYGII 374

I. A. perciformes 374

Families: Percidæ (Freshwater-Perches, Bass, Sea-Perches, Centrarchus), 375--Squamipinnes (Coral-Fishes), 397--Mullidæ (Red-Mullets), 403--Sparidæ (Sea-breams), 405--Hoplognathidæ, 410--Cirrhitidæ, 410--Scorpænidæ, 412--Nandidæ, 418--Polycentridæ, 418--Teuthididæ, 418.

II. A. beryciformes 419

Family: Berycidæ, 420.

III. A. kurtiformes 424

Family: Kurtidæ, 424.

IV. A. polynemiformes 425

Family: Polynemidæ, 425.

V. A. sciæniformes 426

Family: Sciænidæ (Meagres), 426.

VI. A. xiphiiformes 431

Family: Xiphiidæ (Sword-fishes), 431.

VII. A. trichiuriformes 433

Families: Trichiuridæ (Scabbard-fishes, Hairtails), 433--Palæorhynchidæ, 437.

VIII. A. cotto-scombriformes 438

Families: Acronuridæ (Surgeons), 438--Carangidæ (Horse-Mackerels, Pilot-fish, Boar-fish), 440--Cyttidæ (John Dorey), 450--Stromateidæ, 452--Coryphænidæ (Dolphin, Sun-fish), 452--Nomeidæ, 455--Scombridæ (Mackerel, Tunny, Bonito, Albacore, Sucking-fish), 456--Trachinidæ (Stare-gazer, Weever, etc.), 462--Malacanthidæ, 467--Batrachidæ, 467--Psychrolutidæ, 469--Pediculati (Angler, Antennarius, etc.), 469--Cottidæ (Bull-heads, Gurnards), 476--Cataphracti (Flying Gurnards), 480--Pegasidæ, 482.

IX. A. gobiiformes 483

Families: Discoboli (Lump-suckers), 483--Gobiidæ (Gobies, Dragonets), 485.

X. A. blenniiformes 490

Families: Cepolidæ (Band-fishes), 490--Trichonotidæ, 490--Heterolepidotidæ, 491--Blenniidæ (Wolf-fish, Blennies), 492--Acanthoclinidæ, 498--Mastacembelidæ, 499.

XI. A. mugiliformes 499

Families: Sphyrænidæ (Barracudas), 499--Atherinidæ (Atherines), 500--Mugilidæ (Mullets), 501.

XII. A. gastrosteiformes 504

Families: Gastrosteidæ (Sticklebacks), 504--Fistulariidæ (Flute-mouths), 507.

XIII. A. centrisciformes 508

Family: Centriscidæ, 508.

XIV. A. gobiesociformes 510

Family: Gobiesocidæ, 512.

XV. A. channiformes 513

Family: Ophiocephalidæ, 513.

XVI. A. labyrinthibranchii 514

Families: Labyrinthici (Climbing Perch, Gourami), 514--Luciocephalidæ, 519.

XVII. A. lophotiformes 519

Family: Lophotidæ, 519.

XVIII. A. tæniiformes 520

Family: Trachypteridæ (Ribbon-fishes), 520.

XIX. A. notacanthiformes 523

Family: Notacanthidæ, 523.

SECOND ORDER--ACANTHOPTERYGII PHARYNGOGNATHI 523

Families: Pomacentridæ (Coral-fishes), 524--Labridæ (Wrasses, Parrot-wrasses), 525--Embiotocidæ, 533--Chromides, 534.

THIRD ORDER--ANACANTHINI 537

I. A. gadoidei 537

Families: Lycodidæ, 537--Gadidæ (Cod-fishes, Hake, Burbot, Ling, Rockling, Torsk), 539--Ophidiidæ (Brotula, Fierasfer, Sand-eel, Congrogadus), 546--Macruridæ, 551.

II. A. pleuronectoidei 553

Family: Pleuronectidæ (Flat-fishes), 553.

FOURTH ORDER--PHYSOSTOMI 559

Families: Siluridæ; their skeleton, 559--divided into eight subdivisions and sixteen groups; Clariina, 563--Plotosina, 563--Silurina, 565--Hypophthalmina, 566--Bagrina, 567--Amiurina, 567--Pimelodina, 568--Ariina, 569--Doradina, 572--Rhinoglanina, 573--Malapterurina (Electric Catfish), 574--Hypostomatina (Preñadillas, Loricaria, etc.), 575--Aspredinina, 580--Nematogenyina and Trichomycterina, 581--Stegopholina, 581.

Families of Physostomi continued: Scopelidæ, 582--Cyprinidæ (Carps), 587--divided into fourteen groups, viz. Catostomina (Suckers), 588--Cyprinina (Carp, Crucian Carp, Gold-fish, Barbels, Gudgeons), 589--Rohteichthyina, 596--Leptobarbina, 597--Rasborina, 597--Semiplotina, 598--Xenocypridina, 598--Leuciscina (White fish, Tench, Dace, etc.), 598--Rhodeina, 601--Danionina, 601--Hypophthalmichthyina, 602--Abramidina (Bream, Bleak), 602--Homalopterina, 604--Cobitidina (Loaches), 604.

Families of Physostomi continued: Kneriidæ, 606--Characinidæ, 606--Cyprinodontidæ, 613--Heteropygii (Blind Fish of the Mammoth Cave), 618--Umbridæ, 619--Scombresocidæ (Gar-pike, Saury, Half-beak, Flying Fish), 619--Esocidæ (Pike), 623--Galaxiidæ, 624--Mormyridæ, 625--Sternoptychidæ, 627--Stomiatidæ, 629.

Families of Physostomi continued--Salmonidæ: Salmo, difficulty of distinguishing species, 630; constant specific characters, 635--hybrids, 638--sexual development, 638--migratory species and their retention in freshwater, 639--Growth of Salmonoids, 641--their domestication and acclimatisation, 641--species enumerated, 642--Smelt and Capelin, 646--Coregonus, 647--Grayling, 649--marine genera, 650.

Families of Physostomi continued: Percopsidæ, 651--Haplochitonidæ, 651--Gonorhynchidæ, 652--Hyodontidæ (Moon-eye), 653--Pantodontidæ, 653--Osteoglossidæ, 653--Clupeidæ (Herrings, Anchovies, Shads, Mossbanker, Menhaden, etc.), 655--Bathythrissidæ, 663--Chirocentridæ, 663--Alepocephalidæ, 664--Notopteridæ, 664--Halosauridæ, 665--Hoplopleuridæ, 665--Gymnotidæ (Electric Eel), 666--Symbranchidæ, 668--Murænidæ (Eels, Congers, Murænas, etc.), 669.

FIFTH ORDER--LOPHOBRANCHII 678

Families: Solenostomidæ, 678--Syngnathidæ (Pipe-fishes, Sea-horses), 679.

SIXTH ORDER--PLECTOGNATHI 683

Families: Sclerodermi (File-fishes, Coffer-fishes), 684--Gymnodontes (Globe-fishes, Sun-fish), 686.

THIRD SUB-CLASS--CYCLOSTOMATA.

Families: Petromyzontidæ (Lampreys), 691--Myxinidæ, 694.

FOURTH SUB-CLASS--LEPTOCARDII.

Family: Cirrhostomi (Lancelets), 696.

APPENDIX.

DIRECTIONS FOR COLLECTING AND PRESERVING FISHES 697

ALPHABETICAL INDEX 707

INTRODUCTORY REMARKS.

According to the views generally adopted at present, all those Vertebrate animals are referred to the Class of Fishes, which living in water, breathe air dissolved in water by means of gills or branchiæ; whose heart consists of a single ventricle and single atrium; whose limbs, if present, are modified into fins, supplemented by unpaired, median fins; and whose skin is either naked, or covered with scales or osseous plates or bucklers. With few exceptions fishes are oviparous. However, there are not a few members of this Class which show a modification of one or more of these characteristics, as we shall see hereafter, and which, nevertheless, cannot be separated from it. The distinction between the Class of Fishes and that of Batrachians is very slight indeed.

The branch of Zoology which treats of the internal and external structure of fishes, their mode of life, and their distribution in space and time, is termed Ichthyology.