THE STUDY OF FISHES V02

The inter-greatgroupof Actinopteri may be divided intotwo series or subclasses, the Ganoidei, or Chrondrostei, containing those forms, mostlyextinct, which re-tain archaic traits of one

A GUIDE

TO

BY

President o/" Leland Stan_ford Junior University

With Colored Frontispieces and ^07 Illustrations

VARIATIONS IN THE COLOR OF FISHES

The Oniukose or Demon Stinger, Iniviicus japonicus (Cuv. and Val.), from

Wakanoiira, Japan. From nature by Kako Morita.

Surface coloration about lava rocks.

Coloration of specimens living among red algse.

Coloration in deep vi^ater ; Inimicus aurantiacus (Schlegel).

Group?—Systematic Position of Lepidosteus.—Gill on the Ganoids as a

CHAPTER II.

THE GANOIDS {Continued).

Classification of Ganoids.—OrderLysopteri.—The Palseoniscidae.—The somidse.—^The Dorypteridae.—The Dictyopygidae.—Order Chondrostei.

The Leptolepidae.—The Elopidae.—The Albulids.—The Chanidae.—The

Hiodontidas.—The Pterothrissidae.—The Ctenothrissidae.—The

Notopteri-dae.—The Clupeidae.—The Dorosomatidas.—The Engraulididas.—

CHAPTER IV

SALMONID^.

The SalmonFamily.—Coregonus, the Whitefish.—Argyrosomus,theLake

Quinnat Salmon.—The Parent-stream Theory.—The Jadgeska Hatchery.

—

vi Contents

CHAPTER V

Salmo, the Trout and Atlantic Salmon.—The Atlantic Salmon.—The

Ouan-aniche.—TheBlack-spottedTrout.—TheTroutofWesternAmerica.—

Cut-throat or Red-throatedTrout.—Hucho,theHuchen.—Salvelinus, the Charr.

—Cristivomer, the Great Lake Trout.—The Ayu, or Sweetfish.—

CHAPTER VI

THE GRAYLING AND THE SMELT.

The Grayling, or Thymallidae.—The Argentinidae.—TheMicrostomidje.—The

Salangidas, or Icefishes.—The Haplochitonidae.—Stomiatidae.—Suborder

Iniomi, the Lantern-fishes.—Aulopidae.—The Lizard-fishes.—Ipnopidse.

—

Rondeletiidae. — Myctophidae. — Chirothricidae. — Maurolicidas. — The

CHAPTER VII

THE APODES, OR EEL-LIKE FISHES

Archencheli.—Suborder Enchelycephali.—Family AnguilUdae.—

Reproduc-tion of the Eel.—Foodof the Eel.—Larva of the Eel.—Species of Eels.

—

Pug-nosed Eels.—Conger-eels.—The Snake-eels.—Suborder Colocephali,

or Morays.—Family Moringuidae.—Order Carencheli, the Long-necked

CHAPTER VIII

SERIES OSTARIOPHYSI

Ostariophysi.—The Heterognathi.—The Eventognathi.—The Cyprinidae.

—

Species of Dace andShiner.—Chubsof the Pacific Slope.—The Carp and

CHAPTER IX

THE NEMATOGNATHI, OR CATFISHES

The Nematognathi.—Families of Nematognathi.—The Siluridae.—The Sea

Catfish.—The Channel Cats.—Horned Pout.—The Mad-toms.—The OldWorld Catfishes.—The Sisoridae.—The Plotosidae.—The Chlariidje.—TheHypophthalmidaeor Pygidiidae.—The Loricariidae.—The CaUichthyidie Fossil Catfishes.—OrderGymnonoti

Contents viiCHAPTER X.

THE SCYPHOPHORI, HAPLOMI, AND XENOMI.

PAGE

Order Scyphophori.—The Mormyrids.—The Haplomi.—The Pikes.—The

Mudminnows.—TheKilUfishes.—Amblyopsidae.—Kneriidae, etc.—The

PERCESOCES AND RHEGNOPTERI.

Suborder Percesoces.—The Silversides: Atherinidae.—The Mullets:

Aulo-dae.—The Snipefishes: Macrorhamphosidae.—The Shrimp-fishes:

Centri-scidas.—The Lophobranchs.—The Solenostomidae.—The Pipefishes: gnathidae.—The Sea-horses: Hippocampus.—Suborder Hypostomides, the

CHAPTER XIV

SALMOPERC.E AND OTHER TRANSITIONAL

GROUPS-Suborder Salmopercae, the Trout-perches: Percopsidae.—Erismatopteridae.

The Berycoid Fishes.—The Alfonsinos: Berycidas.—The Soldier -fishes:

viii Contents

CHAPTER XVI

PERCOMORPHI.

PAGE

SuborderPercomorphi,theMackerelsandPerches.—TheMackerelTribe:

Scom-broidea.—The TrueMackerels: Scombridae.—TheEscolars: Gempylidae.

—

Scabbard and Cutlass-fishes: Lepidopidae and Trichiuridae.—The rhynchidae.—TheSailfishes: Istiophoridae.—TheSwordfishes: Xiphiidae 258

Palaeo-CHAPTER XVII

CAVALLAS AND PAMPANOS.

The Pampanos: Carangidae.—The Papagallos: Nematistiidae.—The

Blue-fishes: Cheilodipteridae.—The Sergeant -fishes: Rachycentridse.—The ter-fishes: Stromateidas.—The Ragfishes: Icosteidae.—The Pomfrets: Bramidae.—The Dolphins: Coryphaenidae.—The Menidae.—The Pem-

But-pheridae.—^Luvaridae.—The Square-tails: Tetragonuridae.—The Crested

CHAPTER XVIII

PERCOIDEA, OR PERCH-LIKE FISHES

Percoid Fishes.—The Pirate-perches: Aphredoderidae.—The Pigmy fishes: Elassomidae.—The Sunfishes: Centrarchidae.—Crappies and Rock

Sun-Bass—The Black Bass.—The Saleles: Kuhliidas.-The True Perches: Percidae.—Relations of Darters to Perches.—The Perches.—The Darters:

CHAPTER XIX

THE BASS AND THEIR RELATIVES

The Cardinal -fishes: Apogonidas.—The Anomalopidas.—^The Asineopidte

—

TheRobalos: Oxylabracidae.—TheSea-bass: Serranidae.—The Jewfishes.

—The Groupers.—The Serranos.—The Flashers: Lobotidse.—The Big

eyes: Priacanthidae.—The Pentacerotidse.—The Snappers: Lutianidje.

—

The Grunts: Haemulidse.-ThePorgies: Sparida.—ThePicarels: Mffinidje.

CHAPTER XX.

THE SURMULLETS, THE CROAKERS AND THEIR RELATIVES.

TheSurmullets, or Goatfishes: MuUidae.—TheCroakers: Scianids.—The laginidae, etc.—The Jawfishes: Opisthognathidae, etc.—The Stone-wall Perch: Oplegnathidae.—The Swallowers: Chiasmodontidse.—The Mala-

Sil-canthidcB.—The Blanquillos: Latilidce.—The Bandfishes: Cepolidse.

Contents ix

CHAPTER XXI

LABYRINTHICI AND HOLCONOTI.

The Labyrinthine Fishes.—The Chmbing-perches: Anabantidae.—The Gou

ramis: Osphromenidae.—The Snake-head Mullets; Ophicephalids.—SuborderHolconoti, the Surf-fishes.—The Embiotocidae — 365

CHAPTER XXII

CHROMIDES AND PHARYNGOGNATHI.

Suborder Chromides.—The Cichlidae.—The Damsel-fishes: Pomacentridffi.—

Suborder Pharyngognathi.—The Wrasse Fishes: Labridse.-The

CHAPTER XXIII

THE SQUAMIPINNES

The Squamipinnes.—The Scorpididae.—The Boarfishes: Antigoniidae.—The

Arches: Toxotidae.—The Ephippidae.—The Spade-fishes: Ilarchidas.

CHAPTER XXV.

PAREIOPLIT^, OR MAILED-CHEEK FISHES

The Mailed-cheek Fishes.—The Scorpion-fishes: Scorpasnidae.—The fishes: Anoplopomidae.—The Greenlings: Hexagrammidas.—The Flat-

Skil-heads or Kochi: Platycephalidae.—The Sculpins: Cottidae.—The poachers: Agonidae.—The Lump-suckers: Cyclopteridae.—The Sea-snails: Liparididae.—The Baikal Cods: Comephoridae.—Suborder Craniomi: the

Sea-Gurnards, Triglidae.—The Peristediidae.—The Flying Gurnards:

CHAPTER XXVI.

GOBIOIDEI, DISCOCEPHALI, AND T.ENIOSOMI

SuborderGobioidei, the Gobies: Gobiidae.—SuborderDiscocephali, the suckers: Echeneididas.—Suborder Taeniosomi, the Ribbon-fishes.—The

X Contents

CHAPTER XXVII

SUBORDER HETEROSOMATA.

PAGE

The Flatfishes.—Optic Nerves of Flounders.—Ancestry of Flounders.—The

Flounders: Pleuronectidas.—The TurbotTribe: Bothinae.—The Halibut

Tribe: Hippoglossinffi.—The Plaice Tribe: Pleuronectinae.—The Soles:

Soleida.—TheBroadSoles: Achirinae.—The European Soles (Soleinse).—

CHAPTER XXVIII

SUBORDER JUGULARES.

The Jugular-fishes.—The Weevers: Trachinidae.—The Nototheniidae.—The

Leptoscopidae.—The Star-gazers: Uranoscopidae.—The Dragonets:

CHAPTER XXIX.

THE BLENNIES: BLENNIIDiE

TheNorthernBlennies: Xiphidiinae, Stichaeiniae, etc.—TheQuiUfishes: thyidae.—The Blochiidae.—The Pataecidae, etc.—The Gadopsidae, etc.

OPISTHOMI AND ANACANTHINI.

OrderOpisthomi.—OrderAnacanthini.—TheCodfishes: Gadidae.—TheHakes:

CHAPTER XXXI.

TheAngler-fishes.—TheFishing-frogs: Lophiidae.—TheSea-devils: Ceratiidae.

—TheFrogfishes: Antennariidae.—TheBatfishes: Ogcocephalidas 542

Scaphirhynchusplatyrhynchus, Shovel-nosed Sturgeon 20

Polyodonspalhula, Paddle-fish, side-view 21

Polyodonspathida, Paddle-fish,viewfrombelow 21

LowerJawofAmiacalva,showingthe gular plate 33

Elopssaurus,Ten-pounder 42

Tarponatlanticus, TarponorGrandEcaille 43

xii List of

PAGE

Deposits ofGreenRiver Shales, bearing Phareodus, at Fossil,Wyoming 58

ADay's Catchof fossil-fishes. GreenRiverEoceneShales 59

Coregonusclupeijormis, Whitefish 64Argyrosomusnigripinnis, Bluefin Cisco 66

Oncorhynchustschawytscha,QuinnatSalmon (female) 6qOncorhynchustschawytscha,King-salmon(grilse) 70

Oncorhynchusnerka,Male RedSalmon 70

Oncorhynchusgorbuscha,HumpbackSalmon (female) 72

Oncorhynchusmasoic,Masu 72

Oncorhynchusnerka,RedSalmon(mutilateddwarfmaleafterspawning) 76

Oncorhynchustschawytscha,QuinnatSalmon(dying afterspawmng) 77

Oncorhynchustschawytscha, QuinnatSalmon 79

Salmoirideus shasta. RainbowTrout(male)- 98Salmoirideus shasta. RainbowTrout(female) 99Salmorivularis, SteelheadTrout loi

Head of Adult Troutworm, Dibothrium cordiceps. From intestine of white

MediansegmentsofDibothriumcordiceps 103

Salmohenshawi,TahoeTrout 104Salmo stomias. Green-back Trout 105Salmomacdonaldi Yellow-finTrout ofTwinLakes 105

Salmoclarhii spilurus, Rio GrandeTrout 106Salmoclarhii pleuriticus, ColoradoRiverTrout 106Huchoblackistoni, Ito 107

Salvelinusmalma,MalmaTrout

^^ Salvelinusmalma,DollyVardenTrout

^ j.

Plecoglossus altivelis, Ayu,orJapanese Samlet

List of Illustrations xiii

PAGE

Thymallussignijer, AlaskaGrayling 120

Thymallustricolor, Michigan Grayling 122

Pageof William Clark's Handwritingwith Sketch of theEulachon

Salanxhyalocranius, Icefish 128

Synaphobranchuspinnatus 149

Larvaof Conger-eel, Leptocephalus conger 150

Myrichthyspantostigmius 151

Nemichthysavocetta, Thread-eel 152

JawsofNemichthysavocetta 152

Gymnothoraxmoringa,Moray iSS

Notacanthus phasganorus 158, Inrjer view of shoulder-girdle of Buffalo-fish (Ictiobus buhalus), showing the

Weberian apparatusandair-bladder ofCarp 163

European

xiv List of

PAGE

Ericymbabuccata, Silver-jawMinnow 165

HeadofDay-chub,Exoglossummaxillingua 167

Abramischrysoleucus, Shiner 168

LowerPharyngealofPlacopharynxduquesnii 171

Erimyzonsucetta, Creekfish orChub-sucker 172

Pharyngealteeth ofOregonSucker, Catostomus macrocheilus 175

Xyrauchencypho, Razor-back Sucker 175

Ameiurusnebulosus,HornedPout 181

Torpedoeleclricus, Electric Catfish 183

Gnathonemuscurvirostris 189

Esox masquinongy, Muskallunge 192

Cyprinodonvariegatus, RoundMinnow 106

Xiphophorushelleri, Sword-tail Minnow (male) jon

Scombresox saurus, Saury

List of Illustrations xv

PAGE

Hyporhamphusunijasciatus,Halfbeak 212

Cypseluruscalijornicus, Catalina Flying-fish 214

Chirostoma humboldlianum, Pescadobianco 217

Sphyrcenabarracuda,Barracuda 223

Shoulder-girdle ofaStickleback, Gasterosieus aculeatus - 227 Shoulder-girdle of Fistularia petimba, showing greatly extended interclavicle,

Aulostomuschinensis, Trumpet-fish 234

Macrorhamphosussagijue,JapaneseSnipefish. 234

Skull ofaBerycoidfish,Beryxsplendens,showingthe orbitosphenoid 250

Scomberscombrus,Mackerel 260

Scomberomorusmaculatus, SpanishMackerel • 264

268

xvi List of Illustrations

PAGE

Palmorhynchusglarisianus 268Xiphiasgladius,YoungSwordfish 269Xiphiasgladius, Swordfish 270

Trachurustrachurus, Saurel 274Caranguschrysos,Yellow Mackerel 275

Gohiomorusgronovii, PortugueseMan-of-WarFish 285

Coryphxnahippurus,DolphinorDorado 287

Pomoxisannularis, Crappie 297Pomoxisannularis, Crappie(from life) 298AmUoplitesrupestris,RockBass 299

Lepomispallidus, Blue-gill 300Lepomismegalotis. Long-earedSunfish 300Eupomoiisgibbosus. CommonSunfish 301

Hadroplerusaspro, Black-sidedDarter 311

Boleosomaolmstedi, TessellatedDarter 312

Apogon

List of Illustrations xvii

PAGE

Oxylabrax undecimahs, Robalo 319

Promicropsilaiara, Florida Jewfish 323

Eptnephelusstriaius, NassauGrouper: Chernacriolla 324Epinephelus drummond-hayi, JohnPawor SpeckledHind 325

Eptnephelusmorio. RedGrouper 325Epinephelusadscensionis,RedHind 326

Hypoplectrusunicolor nigricans 328Epinephelusniveaius, SnowyGrouper 329

Lutianusgriseus, Gray Snapper 334Lutianusapodus, Schoolmaster 335

Lutianussynagris,Lane Snapperor Biajaiba 336

Ocyuruschrysurus Yellow-tailSnapper 337

Anisoiremusvirginicus, Porkfish 341

Pagrusmajor,RedTaiofJapan 342

Calamusproridens, Little-headPorgy 345

Archosargusunimaculaius, Salema, StripedSheepshead 347

Kyphpsusseciairix, Chopaor Rudder-fish 349

Apomotiscyanellus Blue-green Sunfish 350

Pseudupeneusmaculatus. RedGoatfish orSalmonete 351

Mullusauratus. Golden Surmullet 352

Cynoscionnebulosus, SpottedWeakfish 353

Umbrinasinaloce Yellow-finRoncador 357.

xviii List ofIllustrations

PAGE

Chiasmodonniger, Black Swallower 3^°

Anabasscandens,Climbing Perch 366

Damalichthysargyrosomus, WhiteSurf-fish 374

Pomacentrusleucostictus, Damsel-fish 382

Microspathodondorsalis, Indigo Damsel-fish 384

Lachnolaimusjalcatus, Capitaine or Hogfish 387

Pimelomeloponpulcher, Redfish (male) 389

Pharyngeals ofItahanParrot-fish,5pamomacre^ewie a. Upper; ft,Lower 391

Sparisomaabildgaardi. Red Parrot -fish 392

Upperpharyngeals ofaParrot -fish, Scarus strongylocephalus

393

Lowerpharyngeals of a Parrot-fish, Scarus strongylocephalus 393

HalichcBres bivittatus, SlipperyDickor Doncella, a fish of the coral-reefs 399

Pomacanthusarcuatus, BlackAngel-fish ^^,Holacanthusciliaris, Angel-fish or Isabelita ^

Holacanthustricolor. Rock Beauty

Zanclus canescens, MoorishIdol

g

List of Illustrations xix

PAGE

Osbeckia IcBvis, File-fish

414

Amansesscopas Needle-bearing File-fish 414

LagocephalusIcBvigatus, Silvery Puffer 419

Diodonhystrix, Porcupine-fish 422

Ranzania makua, Kingof the Mackerel,fromHonolulu 425

Scorpanamystes, Sea-scorpion 434

Emmydrichthysvulcanus, BlackNohuor Poison-fish 436

Pleurogrammusmonopterygius, Atka-fish 439

Ophiodonelongatus, CultusCod 440

XX List of Illustrations

PAGE

Uranideatenuis, Miller'sThumb 445

Myxocephalusniger, Pribilof Sculpin 446Myxocephalusoctodecimspinosus, iS-spined Sculpin 447

Cydopieruslumpus,Lumpfish 454

Philypnusdormitor, Guavina de Rio - 460

Abomaetheosioma, DarterGoby 462

EutcBfiiichthys gillii

467

YoungFlounderjust hatched 482

Homocercal Tail ofaFlounder, Paralichthys calijornicus 486

Lophopsetta maculata,Window-pane

List of Illustrations xxi

Syaciumpapillosum,Wide-eyed Flounder 488

Hippoglossushippoglossus, Halibut

492

Achiruslineatus,Hog-chokerSole 496

Neoclinussatiricus, SarcasticBlenny 507

Altictis atlanticus.Rock-skipper 509

Anarkichaslupus, Wolf-iish 517

xxii List of Illustrations

PAGE

Opsanuspardus,LeopardToadfish 525

Porichlhys porosissimus, Singing Fish (withManyLateral Lines) 526

Maslacembelusellipsijer 532Gaduscallarias, Codfish 533

Theragrachalcogramma, Pollock 537

Microgradustomcod, Tomcod 538

Enchelyopuscimbrius, Four-bearded Rockling 539

Coryphanoidescarapinus, showingleptocercal tail 540Calorhynchuscarminatus, Grenadier 541

Ogcocephalus vespertilio, Batfish

55^

CHAPTER I

THE GANOIDS

taxon-omy of the earlier Chordates, or fish-like vertebrates,

we have detached from the main stem one after other along series of archaic or primitive types We havefirst

an-set off those with rudimentary notochord, then those with

retro-gressive development who lose the notochord, then those out skull or brain, then those without limbs or lower jaws

with-The residue assiune the fish-like form of body, but still show

great differences among themselves We have then detachedthose without membrane-bones, or trace of lung or air-bladder

veritable lung, and those with an ancient type of paired fins,

a jointed axis fringed with rays, and those having the palate

having fish-jaws, fish-fins, and in general the structure of the

modem fish. For all these in all their variety, as a class orsubclass, the name Actinopteri, or Actinopterygii, suggested by

Professor Cope, is now generally adopted The shorter form,Actinopteri, being equallycorrect is certainly preferable Thisterm {uktis, ray; nrepov or nrepvS, fin) refers to the structure

of the paired fins. In all these fishes the bones supportingthe fin-rays are highly specialized and at the same time con-cealed by the general integument of the body In general

two bones connect the pectoral fin with the shoulder-girdle

The hypercoracoid is a flat square bone, usually perforated

by a foramen Lying below it and parallelwith it is the larlyformed hypocoracoid Attachedtothemis arowof bones,

irregu-the actinosts, or pterygials, short, often hour-glass-shaped,

which actually support the fin-rays In the more specialized

theactinosts are few (four to six) innumber.

The Series Ganoidei.—

Among the lower nopteri many archaic

Acti-traits still persist, and

in its earlier tives the group ap-

representa-proaches closely to the

Crossopterygii, although

no forms actually mediateareknowneitherliving or fossil. The

inter-greatgroupof Actinopteri

may be divided intotwo

series or subclasses, the

Ganoidei, or Chrondrostei,

containing those forms,

mostlyextinct, which

re-tain archaic traits of one

sort or another, and theTeleostei, or bony fishes,

in which most of theprimitive characters have disappeared Doubtless all of theTeleostei aredescended from a ganoid ancestry

there remains a very great variety of form and structure The

fossil and existing forms do not form continuous series, but resent the tips and remains of many diverging branches perhaps from some Crossopterygian central stock The group constitutes

rep-atleast three distinct orders and, as a whole, does not admit

Tig 1.—Shoulder-girdle of a Flounder,

Para-lichihys californicus (Ayres).

The Ganoids

3perfect definition In most but not all of the species thetail

is distinctly and obviously heterocercal, the lack of symmetry

ofthe tail in some Teleosts being confined to the bones and evident without dissection Most of the Ganoids have theskeleton still cartilaginous, and in some it remains in a veryprimitive condition Usually the Ganoids have an armature

not-of bony plates, diamond-shaped, with an enamel like thatdeveloped on the teeth In all of them the pectoral fin has

numerous basal bones or actinosts All of them have the

air-bladder highly developed, usually cellular and functional as a

lung, but connecting with the dorsal side of the gullet, not withthe ventral side as in the Dipnoans In all living forms there

is a more or less perfect optic chiasma These ancient forms

retain also the many valves of the arterial bulb and the spiralvalve of the intestines foundin themore archaic types of fishes.

But traces of some or all of these structures are found in some

and Crossopterygians to form a great primary class, thyes, as proposed by Dr Giinther Almost everyform of body

Palceich-may be found among the Ganoids In the Mesozoic seas these

fisheswerescarcelylessvariedand perhapsscarcelylessabundant than the Teleosts in the seas of to-day They far exceed theCrossopterygians in n-umber and variety of forms Transitional

forms connecting thetwogroups arethusfarnotrecognized So

far as fossils show, the characteristic actinopterous fin with its

reduced and altered basal bones appeared at once without tervening gradations

in-The name Ganoidei (yavos, brightness; eiiSos, resemblance),

alluding to the enameled plates, was first given by Agassiz to

those forms,mostly extinct, which werecoveredwith bony scales

orhardplates ofone sort or another Asthe term wasoriginallydefined, mailed catfishes, sea-horses, Agonidcs, Arthrodires,Ostracophores, and other wholly unrelated types were includedwith the garpikes and sturgeons as Ganoids Most of these

intruding forms among livingfisheswere eliminatedby Johannes MuUer, who recognized the various archaic characters common

to the existing forms after the removal of the mailed Teleosts

Huxley separated the Crossopterygians as a distinct

4 The Ganoids

group, whileothershave shownthat the Ostracophori and

Arthro-dira should be placed far from the garpike in systematic fication Cope, Woodward, Hay, and others have dropped the

classi-name Ganoid altogether as productive of confusion throughthe many meanings attached to it. Others have kept it as

a convenient group name for the orders of archaic Actinopteri

For these varied and more or less divergent forms it seems venient to retain it. As an adjective "ganoid" is sometimesused as descriptive of bony plates or enameled scales, some-

con-in the sense of archaic, as applied to fishes.

Are the Ganoids a Natural Group?—Several writers haveurged that the Ganoidei, even as thus restricted, should not beconsidered asa naturalgroup, whether subclass, order, or group

of orders The reasons for this view in brief are the following:

1. The group is heterogeneous The Amiidw differ more

from the other Ganoids than they do from the herring-like

Teleosts The garpikes, sturgeons, paddle-fishes likewise verge widely from each other and from the PalaoniscidcB and

di-the PlatysomidcB Each of the living families represents the

residue or culmination of a long series, insome cases advancing,

as in the case of the bowfin, sometimes perhaps degenerating,

as in the case of the sturgeons

2. Of the traits possessed in common by these forms, several

(the cellular air-bladder, the many valves in the heart, thespiral valve in the intestine, the heterocercal tail) are all pos-sessed in greater or less degree by certain Isospondyli or allies

of the herring All these characters are still better developed

in Crossoptergyii and Dipneusti, and each one disappears by

degrees Of the characters drawn from the soft parts we can

know nothing so far as the extinct Ganoids are concerned

3. The optic chiasma, thus far characteristic of Ganoids

as distinct from Teleosts, may have no great value It is urgedthat in closely related species of lizards some have the optic

chiasma and others do not This, however, proves nothing

as to the value of the same character among fishes.

4. The transition from Ganoids to Teleosts is of much the

same character as the transition from, spiny-rayed to rayed fishes, or that from fishes with a duct to the air-bladder

soft-The Ganoids

5

Admitting all this^ it is neverthelessnatural and convenient

to retain the Ganoidei (or Chrondrostei if the older name bediscarded on account of the many meanings attached to it)

as a group equivalent to that of Teleostei within the class orsubclass of Actinopteri It comprises the transitional fornisbetween theCrossopterygii and thebony fishes, andits members

are especially characteristic of the Mesozoic age, ranging fromthe Devonian to the present era

Of the extensive discussion relating to this important tion we may quote two arguments for the retention of the sub-class of Ganoids, the first by Francis M. Balfour and WilliamKitchen Parker, the second from the pen of Theodore Gill.

ques-Balfoiir and Parker (" Structure and Development of dosteus," pp 430-433) thus discuss the

Lepi-Systematic Position of Lepidosteus.— "Alexander Agassiz

con-cludes hismemoir on thedevelopment of Lepidosteus by

point-ing out that in spite of certain affinities in other directionsthis form is 'not so far removed from the bony fishes as hasbeen supposed.' Our own observations go far to confirm Agas-

siz's opinion

"Apart from the complete segmentation, the general

de-velopment of Lepidosteus is strikingly Teleostean In addition

to the general Teleostean features of the embryo and larva,which can only be appreciatedbythose who have had an oppor-ttmity of practically working at the subject, we may point to

the following developmental features * as indicative of

(3) The mode of development of the gut

"(4) The mode of development of the pronephros; thoughthe pronephros of Lepidosteus has primitive characters not

retained by Teleostei

"

(S) The early stages in the development of the vertebral

column.

*The features enumerated above are not in all cases confined to

Lepidos-but always eminentlycharacteristic of the latter.

6 The Ganoids

"In addition to these, so to speak, purely embryonic

char-acters there are not a few important adult characters

" (i) The continuity of the oviducts with the genital glands

"

(2) The small size of the pancreas, and the presence of

numerous so-called pancreatic caeca

"

(3) The somewhat coiled small intestine

"(4) Certain characters of the brain, e.g., the large size ofthe cerebelltun; the presence of the so-called lobi inferiores

on the infundibulum, and of tori semi-circulares in the

mid-brain

"In spite of the undoubtedly important list of features to

which we have just called attention, a list containing not less

important characters, both embryological and adult, separating

Lepidosteus from the Teleostei, can be drawn up:

" (i) The character of the truncus arteriosus

" (2) The fact of the genital ducts joining the ureters

(4) The presence of a well-developed opercular gill.

"(5) The presence of a spiral valve; though this charactermay possibly break down with the extension of our knowledge

"(6) The typical Ganoid characters of thethalamencephalon

and the cerebral hemispheres

"(7) The chiasma of the optic nerves

" (8) The absence of a pecten, and presence of a vascular

"(11) The absence of a division of the muscles into

dorso-lateral and ventro-lateral divisions

"(12) The complete segmentation of the ovum.

that Lepidosteus cannot be classed with the Teleostei; and wehold that Miiller's view is correct, according to which Lepi-

dosteus is a true Ganoid

'

The existence of the Ganoids as a distinct group has,

how-ever, recently been challenged by so distinguished an

The Ganoids

7

ologist as Gunther, and it may therefore be well to consider

how far the group as defined by Miiller is a natural one for

living forms, and how far recent researches enable us to prove upon MiiUer's definitions In his classical memoir thecharacters of the Ganoids are thus shortly stated:

im-"'These fishes are either provided with plate-like angular

or rounded cement-covered scales, or they bear osseous plates,

or are quite naked The fins are often, but not always, beset

with a double or single rowof spinous plates orsplints The

caudal fin embraces occasionally in its upper lobe the endof the

vertebral column, which may be prolonged to the end of theupper lobe Their double nasal openings resemble those of

Teleostei The gills arefree, andlie in a branchial cavityunder

an operculum, like those of Teleostei Many of them have

an accessory organ of respiration, in the form of an opercular

together with the latter; many also have spiracles like

Elas-mobranchii They have many valves in the stem of the aortalike the latter, also a muscular coat in the stem of the aorta.Their ova are transported from the abdominal cavity by ovi-ducts Their optic nerves do not cross each other The in-

testine isoften providedwith aspiral valve,like Elasmobranchii

They have a swimming-bladder with aduct, likemanyTeleostei.Their pelvic fins are abdominal

"

' If we include in a definition only those characters which

are invariable, the Ganoids may be shortly defined as beingthose fish with numerous valvesto the stem of the aorta, which

is also provided with a muscular coat, with free gills, and anoperculum, and with abdominal pelvic fins.'

'

To these distinctive characters he adds, inan appendix to

his paper, the presence ofthe spiral valve, and the absence of aprocessus falciformis and a choroid gland

'

'To the distinctive set of characters given by Mtiller we

may probably add the following:

" (i) Oviducts and urinary ducts always unite, and open

by a common urogenital aperture behind the anus

"(2) Skull hyostylic.

"

(3) Segmentation completein the types so far investigated

(5) Thalamencephalon very large and well developed.

" (6) The ventricle in the posterior part of the cerebrum is

not dividedbehind into lateral halves, the roof oftheundivided

partbeing extremely thin

" (7) Abdominalpores alwayspresent

sufficient to differentiatethe Ganoids as a group; but, curiouslyenough, the only characters, amongst the whole series which

have beengiven,which can beregardedaspeculiartotheGanoids

are (i) the characters of the brain, and (2) the fact of the

ovi-ducts and kidney-ducts iiniting together and opening by a

common pore to the exterior

"This absence of characters peculiar to the Ganoids is an

indication of how widely separated in organization are thedifferent members of this great group

Ganoids have close affinities is the Teleostei The points they have in common with the Elasmobranchii are merely such asare due to the fact that both retain numerous primitive verte-

brate characters,* and the gulf which really separates them is

very wide

"There is again no indication of any close affinity betweenthe Dipnoans and, at any rate, existing Ganoids

"Like the Ganoids, the Dipnoans are no doubt remnants of

a very primitive stock; but in the conversion of the air-bladderinto a true lung, the highly specialized character of their limbs,

their peculiar autostylic skulls, the fact of their ventral nasalopenings leading directly into the mouth, their multisegmentedbars (interspinous bars) directly prolonged from the neural

and haemal and supporting the fin-rays of the unpaired dorsal

*As instances of this we may cite (i) the spiral valve; (2) the frequentpresence of aspiracle; (3) the frequent presenceofacommunication between

the pericardium and the body-cavity; (4) the heterocercal tail.

tVide F. M Balfour, "On the Development ofthe Skeleton ofthe Paired

The Ganoids 9

and ventral fins, and their well-developed cerebral hemispheres,very unlike those of Ganoids and approaching the Amphibian

type, they form a very well-defined group and one very

dis-tinctly separated from the Ganoids

"No doubt the Chondrostean Ganoids are nearly as far

uniting these Ganoids with the Teleostei have been so fullypreservedinthe existingfaunaof the globe that the two groupsalmost run into each other If, in fact, we were anxious to

make any radical change in the ordinary classification of fishes,

it would be by iiniting the Teleostei and Ganoids, or rather

constituting the Teleostei into one of the subgroups of theGanoids, equivalent to the Chondrostei We do not recom-

mend such an arrangement, which in view of the great

pre-ponderance of the Teleostei amongst living fishes would behighly inconvenient, but the step from Amia to the Teleostei

is certainly not so great as that from the Chondrostei to Amia,

andis undoubtedlyless than that from the Selachii to the

Holo-cephali."

Gill on the Ganoids as a Natural Group.—Dr Gill observes("Families of Fishes," 1872): "The name Ganoides (or Ganio-

lepedoti) was originally framed by Prof Agassiz as an ordinal

term for fishes having the scales (when present) angular andcovered with enamel; and in the group so characterized were

combinedthe Ganoids of subsequent authors as well as the

Tele-ostean orders Plectognathi, Lophobranchii, and Nematognathi,

and (subsequently) the genus Sudis {Arapaima), the last beingregarded asa Coelacanth The grouphas notbeenacceptedwiththese limits or characters

" Buttheresearches of Prof Johannes Miiller on the anatomy and classification of the fishes culminated at length in his cele-brated memoirs on those fishes for which heretained the ordinal

name Ganoidei; those memoirs have left an impression onichthyology perhaps more decided than made by any othercontributions to science, and that pubUshed in extenso willever be classical; numerous ashave been themodifications since

introduced into the system, no forms except those recognized

by MuUer (unless it be Dipnoi) have been interjected since

10 The Ganoids

"

It has been objected that the Ganoids do not constitute

a natural group, and that the characters (i.e., chiasma of optic

nerves and multivalvular bulbus arteriosus) alleged by Miiller

to be peculiar to the teleostomous forms combined therein areproblematical, and only inferentially supposed to be common

to the extinct Ganoids so called, and, finally, such objectionscouched in too strong language have culminated inthe assertion

that the characters in question are actually shared by otherphysostome fishes.

"No demonstration, however, has been presented as yetthat any physostome fishes do really have the optic chiasma

and multivalvular bulbus arteriosus, and the statement to thecontrary seems to have been the result of a venial misappre-hensionofProf Kner's statements,ortheoffspring ofimpressions

left on the memory by his assertions, in forgetfulness of hisexact words

" But Prof Kner, in respect to the anatomical characters

referred to, merely objects: (i) that they are problematical,are not confirmable for the extinct types, and were probablynot existent in certain forms that have been referred to theGanoids; (2) the difference in niimber of the valves of the

bulbus arteriosus among recent Ganoids is so great as to show

theunreliability ofthe character; (3) aspiralvalveis developed

in theintestine of several osseous fishes ('genera of the so-called

intermediate clupeoid groups'), as well as in Ganoids; and

(4) the chiasma of the optic nerves in no wise furnishes a

posi-tive character for the Ganoids

"It will be noticed that all these objections (save in the

case of the intestinal spiral valve) are hypothetical and vague

The failure of the intestinal spiral valve, as a diagnostic

char-acter, has long been conceded, and in this case only have theforms that prove the failure been referred to; inthe other cases,where it would be especially desirable to have indicated the

actual types falsifying the universality or exclusiveness of

the characters, they have not been referred to, and the

objec-tions must be met as if they were not known to exist

" (i) The characters in question are, in the sense used

problematical, inasmuch as no examination can be made of

the soft parts of extinct forms, but with equal force may be

The Ganoids 1

urgedthatanycharacters thathave not beenorcannot bedirectlyconfirmed are problematical in the case of all other groups

coordina-tion of parts has been so invariably verified that all

probabili-ties are in favor of similar coordination in any given case

"

(2) There is doubtless considerable difference in the

num-berof valves of the bulbus arteriosus among the various Ganoids,

con-tradistinction to the opposite pair of the Teleosts) in

conjimc-tion with the development of a bulbus arteriosus In no otherforms of Teleostomes have similar relations and structures

been yet demonstrated

(4) The chiasma of the optic nerves is so common to all

with typical physostome Teleosts in the skeleton, heart, etc.,

but which at the same time simulate most certain Ganoids

"Therefore, in view of the evidence hitherto obtained, thearguments against the validity of title, to natural association,

of the Ganoids, have to meet the positive evidence of the ordinations noted; the value of such characteristics and co-ordinations can only be affected or destroyed by the demon-

co-strationthatinallotherrespectsthereis (i) verycloseagreement

of certain of the constituents of the subclass with other forms,

and (2) inversely proportionate dissimilarity of those formsfrom any (not all) other of the Ganoids, and consequently evi-dence ubi plurima nitent against the taxonomic value of thecharacters employed for distinction

"And it is true that thereis agreater superficialresemblancebetween the Hyoganoids (Lepisosteus, Amia, etc.) and ordinaryphysostome Teleosts than between the former and the other

orders ofGanoids, but it is equally truethat they agree in other

than and heart with the more generahzed

I2 The Ganoids

Ganoids They all have, for example, (i) the paraglenal ments undivided (not disintegrated into hypercoracoid, hypo-

ele-coracoid, and mesocoracoid; (2) a humerus (simple or divided,

that is, differentiated into metapterygium and mesopterygium)

and (3) those with ossifiedskeletons agree in the greaterntmiber

of elements in the lower jaw Therefore, until these

coordi-nates fail, it seems advisable to recognize the Ganoids as

con-stituents of a natural series; and especially on account of the

superior taxonomic value of modifications of the brain and

heart in other classes of vertebrates, for the same reason, and

to keep prominently beforethe mind the characters in question,

it appears also advisable to designate the series, -until furtherdiscovery, as a subclass

" But it is quite possiblethat among some of thegeneralizedTeleosts at least traces of some of the characters now consid-

ered to be peculiar to the Ganoids may be discovered In

anticipation of such a possibility, the author had at first

dis-carded the subclass, recognizing the group only as one of

the 'superorders' of the Teleostomes, but reconsiderationconvinces him of the propriety of classification representing

anticipation

"It is remembered that all characters are liable to fail with

increasing knowledge, and the distinctness of groups are but

the intermediate forms; it may in truth be said that ability

to segregate a class into well-defined groups is in ratio to ourignorance of all the terms."

CHAPTER II

THE GANOIDS— Continued

ILASSIFICATION of Ganoids.— The subdivision of theseries of Ganoidei into orders offers great difficultyfromthe fact ofthe varyingrelationships of themem-3ers of the group and the fact that the great majority of the

species are known only from broken skeletons preserved in the

rocks Itis apparently easyto separate thosewithcartilaginousskeletons from those with these bones more or less ossified. It

is also easy to separate those with bony scales or plates fromthose having the scales cycloid But the one type of skeleton

grades into the other, and there is a bony basis even to the

thinnest of scales found in this group Among the multitude

of names and divisions proposed we may recognize six orders

for which the names Lysopteri, Chondrostei, Selachostomi,Pycnodonti, Lepidostei, and Halecomorphi are not inappropriate.

Each of these seems to represent a distinct offshoot from the

first primitive group

Order Lysopteri.—In the most primitive order, called

Lysop-teri {Xvaos, loose; nrnp6v, fin) by Cope, Heterocerci by Zittel

and Eastman, and the "ascending series of Chondrostei" by

Woodward, we find the nearest approach to the

Chondropter-ygians In this order the arches of the vertebras are more or

with bony dermal plates The opercular apparatus is well

developed, with numerous branchiostegals Infraclavicles arepresent, and the fins provided with fulcra Dorsal and anal

fins are present, with rays more numerous than their supports

ventral fin with basal supports which are imperfectly ossified;caudal fin mostly heterocercal, the scales mostly rhombic in

form All the members of this group are now extinct

re-PalcBoniscidcB is the most primitive, ranging from the Devonian

to the Lias, and some of them seem to have entered fresh

waters in the time of the coal-measures These fishes havethe body elongate and provided with one short dorsal fin. The

tail is hetercoercal and the body covered with rhombic plates.Fulcra or rudimentary spine-like scales are developed on theupper edge of the caudal fin in most recent Ganoids, and often

the back has a median row of imdeveloped scales A tude of species and genera are recorded A typical form is

multi-the genus PalcBoniscum* with many species represented in therocks of various parts ofthe world The longest known species

is PalcBoniscum frieslebenense from the Permian of Germany

and England. Palceontscummagnum, sixteenincheslong, occurs

primi-the suspensorittm of the lower jaw becoming more oblique,

the basalbones ofthe dorsal fewer, the dorsal extending farther

forward, and the scales more completely imbricate Other prominent genera are Amblypterus, Eurylepis, Cheirolepis,

Rhadinichthys, Pygopterus, Elonichthys, Mrolepis, Gyrolepis,

Myriolepis, Oxygnathus, Centrolepis, and Holurus

The Platysomidae.— The Platysomidcs are different in foiTn,the body being deep and compressed, often diamond-shaped,

*Thiswordis usually written PalcBoniscus, butBlainville, its author(iSi8)

The Ganoids IS

with very long dorsal and anal fins. In other respects they are

very similar to the PalmoniscidcB, the osteology being the same

The PalcBoniscidcB were rapacious fishes with sharp teeth, thePlatysomidcB less active, and, from the blunter teeth, probablyfeeding on small animals, as crabs and snails

The rhombic enameled scales are highly specialized andheld together as a coat of mail by peg-and-socket joints The most extreme form is Platysomus, with the body very deep

Platysomus gihbosus and other species occur in the Permianrocks of Germany. Cheirodus is similar to Platysomus, but without ventral fins. Eurynotus, the most primitive genus, is

remarkable for its largepectoral fins. Eurynotuscrenatusoccurs

Fig 3.

—

Eurynotus crenatus Agassiz, restored Carboniferous. Family

PlatysomidcE (After Traquair.)

in the Subcarboniferous of Scotland Other genera are

Dorypterus hoffmani, the type of the

sin-gular Palaeozoic family of DorypteridcB, with thoracic or

sub-jugular many-rayed ventrals, is Stromateus-like to all

appear-ance, with distinct resemblances to certain Scombroid forms,

but with a heterocercal tail like a ganoid, imperfectly ossifiedback-bone, and other very archaic characters The body is

i6 The Ganoids

scales are highly developed

althausi, alsofromtheGerman

This species has lower fins

mani, but may be the adult

Dorypterus is regarded by

cialized offshoot from the

many-rayed ventrals andthe

body and fins suggest affinity

Dictyopygidse.—Inthe

pressed, the heterocercal tail

turned upwards, the teeth

hooked, and the bony plates

this group two genera are

tainingnumerousspecies In

terusRedfield,notof Agassiz)

A second species, Dorypteruscoppershales,has beendescribed,

thanDorypterus

hoff-of the same type

{Catopteri-elongate, less

corn-isshortandabruptly

aresharpandusually

well developed Of

recognized, eachRedfieldius (=Catop-thedorsal is inserted

con-Fig 4.

—

Dorypterus hoffmani Germar, restored (After Hancock and Howse.)behind the anal, while in Dictyopygethis is not the case Red-fieldius gracilis and other species are found in the Triassic of

the Connecticut River Dictyopygemacrura isfound inthesame

region, and Dictyopyge catoptera and other species in

The Ganoids 17

Order Chondrostei.—The order Chondrostei (xordpos, lage; oa-teov, bone), as accepted by Woodward, is characterized

carti-by the persistence of the notochord in greater or less degree,

the endoskeleton remaining cartilaginous In all, the axonosts

and baseosts of the median fins are arranged in simple

regu-lar series and the rays are more numerous than the porting elements The shoulder-girdle has a pair of infra-

sup-clavicular plates The pelvic fins have well-developed

base-osts The branchiostegals are few or wanting In the living

forms, and probably in all others, a matter which can never

be ascertained, the optic nerves are not decussating, but form

an optic chiasma, and the intestine is provided with a spiral

valve In all the species there is one dorsal and one anal fin,

separate from the caudal The teeth are small or wanting,the body naked or covered with bony plates; the caudal fin is

usually heterocercal, and on the tail are rhombic plates To

this order, as thus defined, about half of the extinct Ganoids

belong, as well as the modem degenerate formsknown as geonsand perhapsthepaddle-fishes,whichareapparently derivedfrom fishes with rhombic enameled scales The species extendfrom the Upper Carboniferous to the present time, being most

stur-numerous in the Triassic

At this point in Woodward's system diverges a descending

elongate form, this leading through the synthetic type of drosteidcB to the modem sturgeon and paddle-fish, which are

Chon-regarded as degenerate types

The family of Saurorhynchidcs contains pike-like forms, withlong jaws, and long conical teeth set wide apart The tail is

not heterocercal, but short-diphycercal; the bones of the head

are covered with enamel, and those of the roof ofthe skullform

a continuous shield The opercular apparatus is much reduced,

and there arenobranchiostegals Thefinsare all small,withoutfulcra, and the skin has isolated longitudinal series of bony

scutes, but is not coveredwith continuousscales The principal

genus is Saurorhynchus {=Belonorhynchus; the former beingtheearlier name) fromthe Triassic Saurorhynchusacutus fromthe English Triassic is the best known species

The family the Triassic precursors

oper-are a few well-developed caudal rays The caudal has large

fulcra The singlewell-known speciesofthisgroup, Chondrosteus

acipenseroides, is found in the Triassic rocks of England and

reaches a length of about three feet It much resembles a

modem sturgeon, though differing in several technical respects

Chondrosteus pachyurus isbased on the tail ofa species of much

larger size and Gyrosteus niirabilis, also of the English Triassic,

The sturgeons constitute the recent family of AcipenseridcB,

characterized by the prolonged snout and toothless jaws and

the presence of four barbels below the snout In the seridcs there are nobranchiostegals and amedian series of plates

Acipen-is present on the head The body is armed with five rows oflarge bony bucklers,—each often with a hooked spine, sharpest

in the young Besides these, rhombic plates are developed

of the Ganoids, not occiuring before the Lower Eocene, onespecies, Acipenser toUapicus occurring in the London clay

About thirty living species of sturgeon are known, referred

to three genera: Acipenser, found throughout the Northern Hemisphere, Scaphirhynchus, in the Mississippi Valley, and

Kessleria (later called Pseudoscaphirhynchus), in Central Asia

alone Most ofthe speciesbelong to the genus Acipenser, which

abounds in all the rivers and seas in which salmon are found

Some ofthe smaller speciesspendtheirlivesintherivers,