Opening
GUIDE TO THE STUDY OF FISHES
A GUIDE TO THE STUDY OF FISHES
BY
DAVID STARR JORDAN
President of Leland Stanford Junior University
With Colored Frontispieces and 507 Illustrations
IN TWO VOLUMES
VOL II.
"I am the wiser in respect to all knowledge and the better qualified for all fortunes for knowing that there is a minnow in that brook."—Thoreau
NEW YORK HENRY HOLT AND COMPANY 1905
Copyright, 1905
BY
HENRY HOLT AND COMPANY
Published March, 1905
CONTENTS VOL. II.
I. THE GANOIDS
PAGE
Subclass Actinopteri.—The Series Ganoidei.—Are the Ganoids a 1 Natural Group?—Systematic Position of Lepidosteus.—Gill on the Ganoids as a Natural Group.
Chapter II
THE GANOIDS (Continued).
Classification of Ganoids.—Order Lysopteri.—The Palæoniscidæ.—The 13 Platysomidæ.—The Dorypteridæ.—The Dictyopygidæ.—Order Chondrostei.—Order Selachostomi: the Paddle-fishes.—Order Pycnodonti.—Order Lepidostei.—Family Lepisosteidæ.—Embryology of the Garpike.—Fossil Garpikes.—Order Halecomorphi.—Pachycormidæ.— The Bowfins: Amiidæ.—The Oligopleuridæ.
III. ISOSPONDYLI
The Subclass Teleostei, or Bony Fishes.—Order Isospondyli.—The 37 Classification of the Bony Fishes.—Relationships of Isospondyli.—The Clupeoidea.—The Leptolepidæ.—The Elopidæ.—The Albulidæ.—The Chanidæ.—The Hiodontidæ.—The Pterothrissidæ.—The Ctenothrissidæ.—The Notopteridæ.—The Clupeidæ.—The Dorosomatidæ.—The Engraulididæ.—Gonorhynchidæ.—The Osteoglossidæ.—The Pantodontidæ.
IV. SALMONIDÆ
The Salmon Family.—Coregonus, the Whitefish.—Argyrosomus, the Lake 61 Herring.—Brachymystax and Stenodus, the Inconnus.—Oncorhynchus, the Quinnat Salmon.—The Parent-stream Theory.—The Jadgeska Hatchery.—Salmon-packing.
Chapter V
SALMONIDÆ (Continued).
Salmo, the Trout and Atlantic Salmon.—The Atlantic Salmon.—The 89 Ouananiche.—The Black-spotted Trout.—The Trout of Western America.—Cutthroat or Red-throated Trout.—Hucho, the Huchen.— Salvelinus, the Charr.—Cristivomer, the Great Lake Trout.—The Ayu, or Sweetfish.—Cormorant-fishing.—Fossil Salmonidæ.
VI. THE GRAYLING AND THE SMELT
The Grayling, or Thymallidæ.—The Argentinidæ.—The Microstomidæ.— 120 The Salangidæ, or Icefishes.—The Haplochitonidæ.—Stomiatidæ.— Suborder Iniomi, the Lantern-fishes.—Aulopidæ.—The Lizard-fishes.—Ipnopidæ.—Rondeletiidæ.—Myctophidæ.— Chirothricidæ.—Maurolicidæ.—The Lancet-fishes.—The Sternoptychidæ.—Order Lyopomi.
VII. THE APODES, OR EEL-LIKE FISHES
The Eels.—Order Symbranchia.—Order Apodes, or True Eels.—Suborder 139 Archencheli.—Suborder Enchelycephali.—Family Anguillidæ.— Reproduction of the Eel.—Food of the Eel.—Larva of the Eel.— Species of Eels.—Pug-nosed Eels.—Conger-eels.—The Snake-eels.— Suborder Colocephali, or Morays.—Family Moringuidæ.—Order Carencheli, the Long-necked Eels.—Order Lyomeri or Gulpers.— Order Heteromi.
VIII. SERIES OSTARIOPHYSI
Ostariophysi.—The Heterognathi.—The Eventognathi.—The Cyprinidæ.— 159 Species of Dace and Shiner.—Chubs of the Pacific Slope.—The Carp and Goldfish.—The Catostomidæ.—Fossil Cyprinidæ.—The Loaches.
IX. THE NEMATOGNATHI, OR CATFISHES
The Nematognathi.—Families of Nematognathi.—The Siluridæ.—The Sea 177 Catfish.—The Channel Cats.—Horned Pout.—The Mad-toms.—The Old World Catfishes.—The Sisoridæ.—The Plotosidæ.—The Chlariidæ.—The Hypophthalmidæ or Pygidiidæ.—The Loricariidæ.—The Callichthyidæ.—Fossil Catfishes.—Order Gymnonoti.
X. THE SCYPHOPHORI, HAPLOMI, AND XENOMI
Order Scyphophori.—The Mormyridæ.—The Haplomi.—The Pikes.—The Mud 188 minnows.—The Killifishes.—Amblyopsidæ.—Kneriidæ, etc.—The Galaxiidæ.—Order Xenomi.
XI. ACANTHOPTERYGII; SYNENTOGNATHI
Order Acanthopterygii, the Spiny-rayed Fishes.—Suborder 208 Synentognathi.—The Garfishes: Belonidæ.—The Flying-fishes: Exocœtidæ.
XII. PERCESOCES AND RHEGNOPTERI
Suborder Percesoces.—The Silversides: Atherinidæ.—The Mullets: 215 Mugilidæ.—The Barracudas: Sphyrænidæ.—Stephanoberycidæ.— Crossognathidæ.—Cobitopsidæ.—Suborder Rhegnopteri.
XIII. PHTHINOBRANCHII: HEMIBRANCHII, LOPHOBRANCHII, AND
HYPOSTOMIDES.
Suborder Hemibranchii.—The Sticklebacks: Gasterosteidæ.—The 227 Aulorhynchidæ.—Cornet-fishes: Fistulariidæ.—The Trumpet-fishes: Aulostomidæ.—The Snipefishes: Macrorhamphosidæ.—The Shrimp-fishes: Centriscidæ.—The Lophobranchs.—The Solenostomidæ.—The Pipefishes: Syngnathidæ.—The Sea-horses: Hippocampus.—Suborder Hypostomides, the Sea-moths: Pegasidæ.
XIV. SALMOPERCÆ AND OTHER TRANSITIONAL GROUPS
Suborder Salmopercæ, the Trout-perches: Percopsidæ.— 241 Erismatopteridæ.—Suborder Selenichthyes, the Opahs: Lamprididæ.— Suborder Zeoidea.—Amphistiidæ.—The John Dories: Zeidæ.— Grammicolepidæ.
XV. BERYCOIDEI
The Berycoid Fishes.—The Alfonsinos: Berycidæ.—The Soldier-fishes: 250 Holocentridæ.—The Polymixiidæ.—The Pine-cone Fishes: Monocentridæ.
XVI. PERCOMORPHI
Suborder Percomorphi, the Mackerels and Perches.—The Mackerel 258 Tribe: Scombroidea.—The True Mackerels: Scombridæ.—The Escolars: Gempylidæ.—Scabbard and Cutlass-fishes: Lepidopidæ and Trichiuridæ.—The Palæorhynchidæ.—The Sailfishes: Istiophoridæ.— The Swordfishes: Xiphiidæ.
XVII. CAVALLAS AND PAMPANOS
The Pampanos: Carangidæ.—The Papagallos: Nematistiidæ.—The 272 Bluefishes: Cheilodipteridæ.—The Sergeant-fishes: Rachycentridæ.—The Butter-fishes: Stromateidæ.—The Rag-fishes: Icosteidæ.—The Pomfrets: Bramidæ.—The Dolphins: Coryphænidæ.—The Menidæ.—The Pempheridæ.—Luvaridæ.—The Square-tails: Tetragonuridæ.—The Crested Bandfishes: Lophotidæ.
XVIII. PERCOIDEA, OR PERCH-LIKE FISHES
Percoid Fishes.—The Pirate-perches: Aphredoderidæ.—The Pigmy 293 Sunfishes: Elassomidæ.—The Sunfishes: Centrarchidæ.—Crappies and Rock Bass.—The Black Bass.—The Saleles: Kuhliidæ.—The True Perches: Percidæ.—Relations of Darters to Perches.—The Perches.— The Darters: Etheostominæ.
XIX. THE BASS AND THEIR RELATIVES
The Cardinal-fishes: Apogonidæ.—The Anomalopidæ.—The Asineopidæ— 316 The Robalos: Oxylabracidæ.—The Sea-bass: Serranidæ.—The Jewfishes.—The Groupers.—The Serranos.—The Flashers: Lobotidæ.— The Big eyes: Priacanthidæ.—The Pentacerotidæ.—The Snappers: Lutianidæ.—The Grunts: Hæmulidæ.—The Porgies: Sparidæ.—The Picarels: Mænidæ.—The Mojarras: Gerridæ.—The Rudder-fishes: Kyphosidæ.
XX. THE SURMULLETS, THE CROAKERS AND THEIR RELATIVES
The Surmullets, or Goatfishes: Mullidæ.—The Croakers: Sciænidæ.— 351 The Sillaginidæ, etc.—The Jawfishes: Opisthognathidæ, etc.—The Stone-wall Perch: Oplegnathidæ.—The Swallowers: Chiasmodontidæ.— The Malacanthidæ.—The Blanquillos: Latilidæ.—The Bandfishes: Cepolidæ.—The Cirrhitidæ.—The Sandfishes: Trichodontidæ.
XXI. LABYRINTHICI AND HOLCONOTI
The Labyrinthine Fishes.—The Climbing-perches: Anabantidæ.—The 365 Gouramis: Osphromenidæ.—The Snake-head Mullets: Ophicephalidæ.— Suborder Holconoti, the Surf-fishes.—The Embiotocidæ.
XXII. CHROMIDES AND PHARYNGOGNATHI
Suborder Chromides.—The Cichlidæ.—The Damsel-fishes: 380 Pomacentridæ.—Suborder Pharyngognathi.—The Wrasse Fishes: Labridæ.—The Parrot-fishes: Scaridæ.
XXIII. THE SQUAMIPINNES
The Squamipinnes.—The Scorpididæ.—The Boarfishes: Antigoniidæ.—The 397 Arches: Toxotidæ.—The Ephippidæ.—The Spadefishes: Ilarchidæ.—The Platacidæ.—The Butterfly-fishes: Chætodontidæ.—The Pygæidæ.—The Moorish Idols: Zanclidæ.—The Tangs: Acanthuridæ.—Suborder Amphacanthi, the Siganidæ.
XXIV. SERIES PLECTOGNATHI
The Plectognaths.—The Scleroderms.—The Trigger-fishes: Balistidæ.— 411 The File-fishes: Monacanthidæ.—The Spinacanthidæ.—The Trunkfishes: Ostraciidæ.—The Gymnodontes.—The Triodontidæ.—The Globefishes: Tetraodontidæ.—The Porcupine-fishes: Diodontidæ.— The Head-fishes: Molidæ.
XXV. PAREIOPLITÆ, OR MAILED-CHEEK FISHES
The Mailed-cheek Fishes.—The Scorpion-fishes: Scorpænidæ.—The 426 Skilfishes: Anoplopomidæ.—The Greenlings: Hexagrammidæ.—The Flatheads or Kochi: Platycephalidæ.—The Sculpins: Cottidæ.—The Sea-poachers: Agonidæ.—The Lump-suckers: Cyclopteridæ.—The Sea-snails: Liparididæ.—The Baikal Cods: Comephoridæ.—Suborder Craniomi: the Gurnards, Triglidæ.—The Peristediidæ.—The Flying Gurnards: Cephalacanthidæ.
XXVI. GOBIOIDEI, DISCOCEPHALI, AND TÆNIOSOMI
Suborder Gobioidei, the Gobies: Gobiidæ.—Suborder Discocephali, 459 the Shark-suckers: Echeneididæ.—Suborder Tæniosomi, the Ribbon-fishes.—The Oarfishes: Regalecidæ.—The Dealfishes: Trachypteridæ.
XXVII. SUBORDER HETEROSOMATA
The Flatfishes.—Optic Nerves of Flounders.—Ancestry of Flounders.— 481 The Flounders: Pleuronectidæ.—The Turbot Tribe: Bothinæ.—The Halibut Tribe: Hippoglossinæ.—The Plaice Tribe: Pleuronectinæ.— The Soles: Soleidæ.—The Broad Soles: Achirinæ.—The European Soles (Soleinæ).—The Tongue-fishes: Cynoglossinæ.
XXVIII. SUBORDER JUGULARES
The Jugular-fishes.—The Weevers: Trachinidæ.—The Nototheniidæ.—The 499 Leptoscopidæ.—The Star-gazers: Uranoscopidæ.—The Dragonets: Callionymidæ.—The Dactyloscopidæ.
XXIX. THE BLENNIES: BLENNIIDÆ
The Northern Blennies: Xiphidiinæ, Stichæiniæ, etc.—The 507 Quillfishes: Ptilichthyidæ.—The Blochiidæ.—The Patæcidæ, etc.— The Gadopsidæ, etc.—The Wolf-fishes: Anarhichadidæ.—The Eel-pouts: Zoarcidæ.—The Cusk-eels: Ophidiidæ.—Sand-lances: Ammodytidæ.—The Pearlfishes: Fierasferidæ.—The Brotulidæ.— Ateleopodidæ.—Suborder Haplodoci.—Suborder Xenopterygii.
XXX. OPISTHOMI AND ANACANTHINI
Order Opisthomi.—Order Anacanthini.—The Codfishes: Gadidæ.—The 532 Hakes: Merluciidæ.—The Grenadiers: Macrouridæ.
XXXI. ORDER PEDICULATI: THE ANGLERS
The Angler-fishes.—The Fishing-frogs: Lophiidæ.—The Sea-devils: 542 Ceratiidæ.—The Frogfishes: Antennariidæ.—The Batfishes: Ogcocephalidæ.
LIST OF ILLUSTRATIONS VOL. II.
PAGE
Shoulder-girdle of a Flounder, Paralichthys californicus 2
Palæoniscum frieslebenense 14
Eurynotus crenatus 15
Dorypterus hoffmani 16
Chondrosteus acipenseroides 18
Acipenser sturio, Common Sturgeon 19
Acipenser rubicundus, Lake Sturgeon 20
Scaphirhynchus platyrhynchus, Shovel-nosed Sturgeon 20
Polyodon spathula, Paddle-fish, side-view 21
Polyodon spathula, Paddle-fish, view from below 21
Psephurus gladius 21
Gyrodus hexagonus 22
Mesturus verrucosus 23
Semionotus kapffi 24
Dapedium politum 25
Tetragonolepis semicinctus 26
Isopholis orthostomus 27
Lepisosteus osseus, Long-nosed Garpike 27
Caturus elongatus 28
Notagogus pentlandi 28
Ptycholepis curtus 28
Pholidophorus crenulatus 29
Lepisosteus tristœchus, Alligator-gar 31
Lower Jaw of Amia calva, showing the gular plate 33
Amia calva, Bowfin (female) 35
Megalurus elegantissimus 36
Leptolepis dubius 41
Elops saurus, Ten-pounder 42
Holcolepis lewesiensis 42
Tarpon atlanticus, Tarpon or Grand Écaille 43
Albula vulpes, Lady-fish 44
Chanos chanos, Milkfish 45
Hiodon tergisus, Mooneye 45
Istieus grandis 46
Chirothrix libanicus 46
Skeleton of Portheus molossus 47
Ctenothrissa vexillifera 48
Clupea harengus, Herring 49
Pomolobus pseudoharengus, Alewife 50
Brevoortia tyrannus, Menhaden 51
Diplomystus humilis 52
Dorosoma cepedianum, Hickory-shad 53
Anchovia perthecata, Silver Anchovy 54
Notogoneus osculus 55
Phareodus testis 57
Deposits of Green River Shales, bearing Phareodus, at Fossil, 58 Wyoming
A Day's Catch of fossil-fishes, Green River Eocene Shales 59
Alepocephalus agassizii 60
Coregonus williamsoni, Rocky Mountain Whitefish 63
Coregonus clupeiformis, Whitefish 64
Argyrosomus nigripinnis, Bluefin Cisco 66
Stenodus mackenziei, Inconnu 67
Oncorhynchus tschawytscha, Quinnat Salmon (female) 69
Oncorhynchus tschawytscha, King-salmon (grilse) 70
Oncorhynchus nerka, Male Red Salmon 70
Oncorhynchus gorbuscha, Humpback Salmon (female) 72
Oncorhynchus masou, Masu 72
Oncorhynchus nerka, Red Salmon (mutilated dwarf male after 76 spawning)
Oncorhynchus tschawytscha, Quinnat Salmon (dying after spawning) 77
Oncorhynchus tschawytscha, Quinnat Salmon 79
Salmo irideus shasta, Rainbow Trout (male) 98
Salmo irideus shasta, Rainbow Trout (female) 99
Salmo rivularis, Steelhead Trout 101
Head of Adult Trout-worm, Dibothrium cordiceps. From intestine 103 of white pelican
Median segments of Dibothrium cordiceps 103
Salmo henshawi, Tahoe Trout 104
Salmo stomias, Green-back Trout 105
Salmo macdonaldi, Yellow-fin Trout of Twin Lakes 105
Salmo clarkii spilurus, Rio Grande Trout 106
Salmo clarkii pleuriticus, Colorado River Trout 106
Hucho blackistoni, Ito 107
Salvelinus oquassa, Rangeley Trout 108
Salvelinus aureolus, Sunapee Trout 109
Salvelinus fontinalis, Speckled Trout (male) 110
Salvelinus fontinalis, Speckled Trout 111
Salvelinus malma, Malma Trout 113
Salvelinus malma, Dolly Varden Trout 114
Cristivomer namaycush, Great Lake Trout 114
Plecoglossus altivelis, Ayu, or Japanese Samlet 116
Thymallus signifer, Alaska Grayling 120
Thymallus tricolor, Michigan Grayling 122
Osmerus mordax, Smelt 123
Thaleichthys pretiosus, Eulachon or Ulchen 124
Page of William Clark's Handwriting with Sketch of the Eulachon 125 (Thaleichthys pacificus)
Mallotus villosus, Capelin 126
Salanx hyalocranius, Icefish 128
Stomias ferox 128
Chauliodus sloanei 129
Synodus fætens, Lizard-fish 130
Ipnops murrayi 131
Cetomimus gillii 132
Diaphus lucidus, Headlight-fish 132
Myctophum opalinum, Lantern-fish 133
Ceratoscopelus madeirensis, Lantern-fish 133
Rhinellus furcatus 134
Plagyodus ferox, Lancet-fish 135
Eurypholis sulcidens 136
Eurypholis freyeri 137
Argyropelecus olfersi 137
Aldrovandia gracilis 138
Anguilla chrisypa, Common Eel 143
Anguilla chrisypa, Larva of Common Eel 148
Simenchelys parasiticus, Pug-nosed Eel 149
Synaphobranchus pinnatus 149
Leptocephalus conger, Conger-eel 150
Larva of Conger-eel, Leptocephalus conger 150
Xyrias revulsus 151
Myrichthys pantostigmius 151
Ophichthus ocellatus 151
Nemichthys avocetta, Thread-eel 152
Jaws of Nemichthys avocetta 152
Muræna retifera 153
Gymnothorax berndti 154
Gymnothorax jordani 155
Gymnothorax moringa, Moray 155
Derichthys serpentinus 156
Gastrostomus bairdi, Gulper-eel 156
Notacanthus phasganorus 158
Inner view of shoulder-girdle of Buffalo-fish (Ictiobus 160 bubalus), showing the mesocoracoid
Weberian apparatus and air-bladder of Carp 160
Brycon dentex 162
Pharyngeal bones and teeth of European Chub, Leuciscus cephalus 163
Rhinichthys dulcis, Black-nosed Dace 164
Notropis hudsonius, White Chub 165
Ericymba buccata, Silver-jaw Minnow 165
Notropis whipplei, Silverfin 166
Campostoma anomalum, Stone-roller 167
Head of Day-chub, Exoglossum maxillingua 167
Semotilus atromaculatus, Horned Dace 168
Abramis chrysoleucus, Shiner 168
Ptychocheilus grandis, Squawfish 169
Leuciscus lineatus, Chub of the Great Basin 169
Lower Pharyngeal of Placopharynx duquesnii 171
Erimyzon sucetta, Creekfish or Chub-sucker 172
Ictiobus cyprinella, Buffalo-fish 173
Carpiodes cyprinus, Carp-sucker 173
Catostomus commersoni, Common Sucker 174
Catostomus occidentalis, California Sucker 174
Pharyngeal teeth of Oregon Sucker, Catostomus macrocheilus 175
Xyrauchen cypho, Razor-back Sucker 175
Felichthys felis, Gaff-topsail Cat 179
Galeichthys milberti, Sea Catfish 179
Ictalurus punctatus, Channel Catfish 180
Ameiurus nebulosus, Horned Pout 181
Schilbeodes furiosus, Mad-tom. Showing the poisoned pectoral 182 spine
Torpedo electricus, Electric Catfish 183
Chlarias breviceps, African Catfish 185
Loricaria aurea, Mailed Catfish from Venezuela 186
Gnathonemus curvirostris 189
Esox lucius, Pike 191
Esox masquinongy, Muskallunge 192
Umbra pygmæa, Mud-minnow 193
Anableps dovii, Four-eyed Fish 195
Cyprinodon variegatus, Round Minnow 196
Jordanella floridæ, Everglade Minnow 197
Fundulis majalis, Mayfish (male) 198
Fundulis majalis, Mayfish (female) 198
Zygonectes notatus, Top-minnow 198
Empetrichthys merriami, Death Valley Fish 199
Xiphophorus helleri, Sword-tail Minnow (male) 199
Goodea luitpoldi, a Viviparous Fish 200
Chologaster cornutus, Dismal Swamp Fish 201
Typhlichthys subterraneus, Blind Cave-fish 202
Amblyopsis spelæus, Blindfish of the Mammoth Cave 203
Dallia pectoralis, Alaska Blackfish 206
Tylosurus acus, Needle-fish 210
Scombresox saurus, Saury 212
Hyporhamphus unifasciatus, Halfbeak 212
Fodiator acutus, Sharp-nosed Flying-fish 213
Cypselurus californicus, Catalina Flying-fish 214
Chirostoma humboldtianum, Pescado blanco 217
Kirtlandia vagrans, Silverside or Brit 217
Atherinopsis californiensis, Blue Smelt or Pez del Rey 218
Iso flos-maris, Flower of the Waves 218
Mugil cephalus, Striped Mullet 221
Joturus pichardi, Joturo or Bobo 222
Sphyræna barracuda, Barracuda 223
Cobitopsis acuta 224
Shoulder-girdle of a Threadfin, Polydactylus approximans 225
Polydactylus octonemus, Threadfin 225
Shoulder-girdle of a Stickleback, Gasterosteus aculeatus 227
Shoulder-girdle of Fistularia petimba, showing greatly extended 227 interclavicle, the surface ossified
Gasterosteus aculeatus, Three-spined Stickleback 232
Apeltes quadracus, Four-spined Stickleback 232
Aulostomus chinensis, Trumpet-fish 234
Macrorhamphosus sagifue, Japanese Snipefish 234
Æoliscus strigatus, Shrimp-fish 235
Æoliscus heinrichi 235
Solenostomus cyanopterus 237
Hippocampus hudsonius, Sea-horse 238
Zalises umitengu, Sea-moth 240
Percopsis guttatus, Sand-roller 241
Erismatopterus endlicheri 242
Columbia transmontana, Oregon Trout-perch 242
Shoulder-girdle of the Opah, Lampris guttatus (Brünnich), 243 showing the enlarged infraclavicle
Ligatures_Semiophorus velifer_ 246
Amphistium paradoxum 247
Zeus faber, John Dory 248
Skull of a Berycoidfish, Beryx splendens, showing the 250 orbitosphenoid
Beryx splendens 251
Hoplopteryx lewesiensis 252
Paratrachichthys prosthemius 253
Holocentrus ascenscionis, Soldier-fish 254
Holocentrus ittodai 254
Ostichthys japonicus 255
Monocentris japonicus, Pine-cone Fish 256
Scomber scombrus, Mackerel 260
Germo alalunga, Long-fin Albacore 263
Scomberomorus maculatus, Spanish Mackerel 264
Trichiurus lepturus, Cutlass-fish 268
Palæorhynchus glarisianus 268
Xiphias gladius, Young Swordfish 269
Xiphias gladius, Swordfish 270
Naucrates ductor, Pilot-fish 273
Seriola lalandi, Amber-fish 273
Trachurus trachurus, Saurel 274
Carangus chrysos, Yellow Mackerel 275
Trachinotus carolinus, the Pampano 277
Cheilodipterus saltatrix, Bluefish 279
Rachycentron canadum, Sergeant-fish 282
Peprilus paru, Harvest-fish 284
Gobiomorus gronovii, Portuguese Man-of-War Fish 285
Coryphæna hippurus, Dolphin or Dorado 287
Mene maculata 288
Gasteronemus rhombeus 289
Pempheris mulleri, Catalufa de lo Alto 289
Pempheris nyctereutes 290
Luvarus imperialis, Louvar 290
Aphredoderus sayanus, Pirate Perch 295
Elassoma evergladei, Everglade Pigmy Perch 295
Skull of the Rock Bass, Ambloplites rupestris 296
Pomoxis annularis, Crappie 297
Pomoxis annularis, Crappie (from life) 298
Ambloplites rupestris, Rock Bass 299
Mesogonistius chætodon, Banded Sunfish 299
Lepomis pallidus, Blue-gill 300
Lepomis megalotis, Long-eared Sunfish 300
Eupomotis gibbosus, Common Sunfish 301
Micropterus dolomieu, Small Mouth Black Bass 303
Micropterus salmoides, Large Mouth Black Bass 305
Perca flavescens, Yellow perch 308
Stizostedion canadense, Sauger 309
Aspro asper, Aspron 309
Zingel zingel, Zingel 310
Percina caprodes, Log-perch 311
Hadropterus aspro, Black-sided Darter 311
Diplesion blennioides, Green-sided Darter 312
Boleosoma olmstedi, Tessellated Darter 312
Crystallaria asprella, Crystal Darter 313
Ammocrypta clara, Sand-darter 313
Etheostoma jordani 314
Etheostoma camurum, Blue-breasted Darter 314
Apogon retrosella, Cardinal-fish 316
Telescopias gilberti, Kuromutsu 318
Apogon semilineatus 319
Oxylabrax undecimalis, Robalo 319
Morone americana, White Perch 322
Promicrops itaiara, Florida Jewfish 323
Epinephelus striatus, Nassau Grouper: Cherna criolla 324
Epinephelus drummond-hayi, John Paw or Speckled Hind 325
Epinephelus morio, Red Grouper 325
Epinephelus adscensionis, Red Hind 326
Mycteroperca venenosa, Yellow-fin Grouper 327
Hypoplectrus unicolor nigricans 328
Epinephelus niveatus, Snowy Grouper 329
Rypticus bistrispinus, Soapfish 330
Lobotes surinamensis, Flasher 331
Priacanthus arenatus, Catalufa 331
Pseudopriacanthus altus, Bigeye 332
Lutianus griseus, Gray Snapper 334
Lutianus apodus, Schoolmaster 335
Hoplopagrus guntheri 336
Lutianus synagris, Lane Snapper or Biajaiba 336
Ocyurus chrysurus, Yellow-tail Snapper 337
Etelis oculatus, Cachucho 337
Xenocys jessiæ 338
Aphareus furcatus 339
Hæmulon plumieri, Grunt 340
Anisotremus virginicus, Porkfish 341
Pagrus major, Red Tai of Japan 342
Ebisu, the Fish-god of Japan, bearing a Red Tai 343
Stenotomus chrysops, Scup 344
Calamus bajonado, Jolt-head Porgy 345
Calamus proridens, Little-head Porgy 345
Diplodus holbrooki 346
Archosargus unimaculatus, Salema, Striped Sheepshead 347
Xystæma cinereum, Mojarra 348
Gerres olisthostomus, Irish Pampano 349
Kyphosus sectatrix, Chopa or Rudder-fish 349
Apomotis cyanellus, Blue-green Sunfish 350
Pseudupeneus maculatus, Red Goatfish or Salmonete 351
Mullus auratus, Golden Surmullet 352
Cynoscion nebulosus, Spotted Weakfish 353
Bairdiella chrysura, Mademoiselle 355
Sciænops ocellata, Red Drum 356
Umbrina sinaloæ, Yellow-fin Roncador 357
Menticirrhus americanus, Kingfish 357
Pogonias chromis, Drum 358
Gnathypops evermanni 359
Opisthognathus macrognathus, Jawfish 359
Opisthognathus nigromarginatus 360
Chiasmodon niger, Black Swallower 360
Cirrhitus rivulatus 364
Trichodon trichodon, Sandfish 364
Anabas scandens, Climbing Perch 366
Channa formosana 371
Ophicephalus barca, Snake-headed China-fish 371
Cymatogaster aggregatus, White Surf-fish 372
Hysterocarpus traski, Fresh-water Viviparous Perch 373
Hypsurus caryi 373
Damalichthys argyrosomus, White Surf-fish 374
Rhacochilus toxotes, Thick-lipped Surf-fish 374
Hypocritichthys analis, Silver Surf-fish, Viviparous 375
Hysterocarpus traski, Viviparous Perch (male) 379
Hypsypops rubicunda, Garibaldi 382
Pomacentrus leucostictus, Damsel-fish 382
Glyphisodon marginatus, Cockeye Pilot 383
Microspathodon dorsalis, Indigo Damsel-fish 384
Tautoga onitis, Tautog 384
Tautoga onitis, Tautog 386
Lachnolaimus falcatus, Capitaine or Hogfish 387
Xyrichthys psittacus, Razor-fish 388
Pimelometopon pulcher, Redfish (male) 389
Lepidaplois perditio 389
Pharyngeals of Italian Parrot-fish, Sparisoma cretense. a, 391 Upper; b, Lower
Jaws of Parrot-fish, Calotomus xenodon 391
Cryptotomus beryllinus 391
Sparisoma hoplomystax 392
Sparisoma abildgaardi, Red Parrot-fish 392
Jaws of Blue Parrot-fish, Scarus cæruleus 393
Upper pharyngeals of a Parrot-fish, Scarus strongylocephalus 393
Lower pharyngeals of a Parrot-fish, Scarus strongylocephalus 393
Scarus emblematicus 394
Scarus cæruleus, Blue Parrot-fish 394
Scarus vetula, Parrot-fish 395
Halichæres bivittatus, Slippery Dick or Doncella, a fish of the 399 coral-reefs
Monodactylus argenteus 397
Psettus sebæ 399
Chætodipterus faber, Spadefish 401
Chætodon capistratus, Butterfly-fish 402
Pomacanthus arcuatus, Black Angel-fish 403
Holacanthus ciliaris, Angel-fish or Isabelita 404
Holacanthus tricolor, Rock Beauty 405
Zanclus canescens, Moorish Idol 406
Teuthis cæruleus, Blue Tang 407
Teuthis bahianus, Brown Tang 408
Balistes carolinensis, Trigger-fish 412
Osbeckia lævis, File-fish 414
Amanses scopas, Needle-bearing File-fish 414
Stephanolepis hispidus, Common File-fish 415
Lactophrys tricornis, Horned Trunkfish, Cowfish, or Cuckold 416
Ostracion cornutum, Horned Trunkfish 416
Lactophrys bicaudalis, Spotted Trunkfish 416
Lactophrys bicaudalis, Spotted Trunkfish (face view) 417
Lactophrys triqueter, Spineless Trunkfish 417
Lactophrys trigonus, Hornless Trunkfish 418
Skeleton of the Cowfish, Lactophrys tricornis 418
Lagocephalus lævigatus, Silvery Puffer 419
Spheroides spengleri, Puffer, Inflated 420
Spheroides maculatus, Puffer 420
Tetraodon meleagris 421
Tetraodon setosus, Bristly Globefish 422
Diodon hystrix, Porcupine-fish 422
Chilomycterus schœpfi, Rabbit-fish 423
Mola mola, Headfish (adult) 424
Ranzania makua, King of the Mackerel, from Honolulu 425
Sebastes marinus, Rosefish 427
Skull of Scorpænichthys marmoratus 427
Sebastolobus altivelis 428
Sebastodes mystinus, Priest-fish 430
Sebastichthys serriceps 431
Sebastichthys nigrocinctus, Banded Rockfish 432
Scorpæna grandicornis, Lion-fish 433
Scorpæna mystes, Sea-scorpion 434
Pterois volitans, Lion-fish or Sausolele 435
Emmydrichthys vulcanus, Black Nohu or Poison-fish 436
Snyderina yamanokami 437
Trachicephalus uranoscopus 438
Anoplopoma fimbria, Skilfish 438
Pleurogrammus monopterygius, Atka-fish 439
Hexagrammos decagrammus, Greenling 440
Ophiodon elongatus, Cultus Cod 440
Jordania zonope 442
Astrolytes notospilotus 442
Hemilepidotus jordani, Irish Lord 443
Triglops pingeli 443
Enophrys bison, Buffalo Sculpin 443
Ceratocottus diceraus 444
Elanura forficata 444
Cottus punctulatus, Yellowstone Miller's Thumb 444
Uranidea tenuis, Miller's Thumb 445
Cottus evermanni 445
Cottus gulosus, California Miller's Thumb 446
Myxocephalus niger, Pribilof Sculpin 446
Myxocephalus octodecimspinosus, 18-spined Sculpin 447
Oncocottus quadricornis 447
Blepsias cirrhosus 448
Hemitripterus americanus, Sea-raven 448
Oligocottus maculosus 449
Ereunias grallator 450
Psychrolutes paradoxus, Sleek Sculpin 451
Gilbertidia sigolutes 451
Rhamphocottus richardsoni, Richardson's Sculpin 451
Stelgis vulsus 451
Draciscus sachi 452
Pallasina barbata, Agonoid-fish 453
Aspidophoroides monopterygius 453
Cyclopterus lumpus, Lumpfish 454
Crystallias matsushimæ, Liparid 454
Neoliparis mucosus, Snailfish 455
Prionotus evolans, Sea-robin 456
Cephalacanthus volitans, Flying Gurnard 457
Peristedion miniatum 457
Philypnus dormitor, Guavina de Rio 460
Eleotris pisonis, Dormeur 460
Dormitator maculatus, Guavina mapo 461
Vireosa hanæ 461
Gobionellus oceanicus, Esmeralda de Mar 461
Pterogobius daimio 462
Aboma etheostoma, Darter Goby 462
Gillichthys mirabilis, Long-jawed Goby 463
Boleophthalmus chinensis, Pond-skipper 466
Periophthalmus barbarus, Mud-skippy 466
Eutæniichthys gillii 467
Leptecheneis naucrates, Sucking-fish or Pegador 468
Rhombochirus osteochir 469
Regalecus russelli, Glesnæs Oarfish 476
Trachypterus rex-salmonorum, Dealfish or King of the Salmon 478
Young Flounder just hatched 482
Pseudopleuronectes americanus, Larval Flounder 483
Larval Stages of Platophrys podas, a Flounder 484
Platophrys lunatus, Peacock Flounder 485
Heterocercal Tail of Young Trout, Salmo fario 486
Homocercal Tail of a Flounder, Paralichthys californicus 486
Lophopsetta maculata, Window-pane 487
Syacium papillosum, Wide-eyed Flounder 488
Etropus crossotus 489
Hippoglossus hippoglossus, Halibut 492
Paralichthys dentatus, Wide-mouthed Flounder 493
Liopsetta putnami, Eel-back Flounder 494
Platichthys stellatus, Starry Flounder 495
Achirus lineatus, Hog-choker Sole 496
Symphurus plagiusa 498
Pteropsaron evolans 502
Bathymaster signatus 503
Ariscopus iburius 504
Astroscopus guttatus, Star-gazer 505
Neoclinus satiricus, Sarcastic Blenny 507
Gibbonsia evides, Kelp Blenny 508
Blennius cristatus 508
Alticus atlanticus, Rock-skipper 509
Alticus saliens, Lizard-skipper 509
Emblemaria atlantica 510
Scartichthys enosimæ, Fish of the rock-pools of the sacred 510 island of Enoshima, Japan
Zacalles bryope 511
Bryostemma tarsodes 511
Exerpes asper 511
Pholis gunnellus, Gunnel 512
Xiphistes chirus 512
Ozorthe dictyogramma 513
Stichæus punctatus 513
Bryostemma otohime 514
Ptilichthys goodei, Quillfish 514
Blochius longirostris 514
Xiphasia setifera 515
Cryptacanthodes maculatus, Wrymouth 516
Anarhichas lupus, Wolf-fish 517
Skull of Anarrhichthys ocellatus 517
Zoarces anguillaris, Eel-pout 518
Lycodes reticulatus, Eel-pout 519
Lycenchelys verrilli 519
Scytalina cerdale 519
Rissola marginata, Cusk-eel 520
Lycodapus dermatinus 520
Ammodytes americanus, Sand-lance 521
Embolichthys mitsukurii 521
Fierasfer dubius, Pearlfish, Embedded in Pearl 522
Fierasfer acus, Pearlfish 523
Brotula barbata 524
Lucifuga subterranea, Blind Brotula 524
Opsanus pardus, Leopard Toadfish 525
Porichthys porosissimus, Singing Fish (with Many Lateral Lines) 526
Aspasma ciconiæ 530
Caularchus mæandricus, Clingfish 531
Mastacembelus ellipsifer 532
Gadus callarias, Codfish 533
Skull of Haddock, Melanogrammus æglifinus 536
Melanogrammus æglifinus, Haddock 536
Theragra chalcogramma, Pollock 537
Microgadus tomcod, Tomcod 538
Lota maculosa, Burbot 539
Enchelyopus cimbrius, Four-bearded Rockling 539
Merluccius productus, California Hake 540
Coryphænoides carapinus, showing leptocercal tail 540
Cælorhynchus carminatus, Grenadier 541
Steindachnerella argentea 541
Lophius litulon, Anko or Fishing-frog 545
Cryptopsaras couesi 547
Ceratias holbolli, Deep-sea Angler 548
Caulophryne jordani 548
Pterophryne tumida, Sargassum-fish, one of the Anglers 549
Antennarius nox, Fishing-frog 550
Shoulder-girdle of a Batfish, Ogcocephalus radiatus 551
Antennarius scaber, Frogfish 551
Ogcocephalus vespertilio 552
Ogcocephalus vespertilio, Batfish 553
Ogcocephalus vespertilio, Batfish 553
ERRATA[1] VOL. II
Page xviii, line 7, for Ophicæphalus read Ophicephalus
xviii, " 37, for Mononactylus read Monodactylus
xix, " 33, for Trachicephales read Trachicephalus
xx, " 37, for Regaleaus glesneacsanius read Regalecus russelli
xxi, " 2, for Etopus read Etropus
xxi, " 35, for Zoacres read Zoarces
1, " 7, for jaws read jaw
14, " 9, for hetercoercal read heterocercal
136, " 3, for Evermannellus read Evermannella
170, " 11, for the fin read the dorsal fin
171, " 10, for have read has
303, legend, for Lacepède read Lacépède
307, line 14, for vertebrate read vertebral
311, " 12, not clearly stated. The air-bladder is least developed in those species which cling closest to the bottom of the stream
350, legend, for Apomotes read Apomotis
355, line 18, for ours read our
357, " 14, for chætodon read Chætodon
358, " 17, for Scriænidæ read Sciænidæ
360, " 14, for Percesoces read Percesoces
409, " 16, for naseus read Naseus
419, " 23, for of the generic of this group read separating the group into genera
440, " 17, for Chinnook read Chinook
459, " 24, for but the most read but most
459, " 25, for thme read them
467, " 14, for Typhogobius read Typhlogobius
472, lines 34, omit "but never in the United States". 35, Specimens of Regalecus have been taken at Anclote Key, Florida, and at the Tortugas.
580, col. 3, line 17, for 165 read 105
The adoption of the Code of the International Congress of Zoology necessitates a few changes in generic names used in this book.
Thus Amia (ganoid) becomes Amiatus Apogon becomes Amia Scarus becomes Callyodon Teuthis becomes Hepatus Acanthurus becomes Monoceros Paramia becomes Cheilodipterus Centropomus (Oxylabrax) remains Centropomus Lucioperca (Centropomus) becomes Sander Pomatomus (Cheilodipterus) remains Pomatomus Nomeus (Gobiomorus) remains Nomeus Galeus (Galeorhinus) remains Galeus Carcharias (Carcharhinus) remains Carcharias
Footnote 1:
For most of this list of errata I am indebted to the kindly interest of Dr. B. W. Evermann.
I. THE GANOIDS
=SUBCLASS Actinopteri.=—In our glance over the taxonomy of the earlier Chordates, or fish-like vertebrates, we have detached from the main stem one after another a long series of archaic or primitive types. We have first set off those with rudimentary notochord, then those with retrogressive development who lose the notochord, then those without skull or brain, then those without limbs or lower jaw. The residue assume the fish-like form of body, but still show great differences among themselves. We have then detached those without membrane-bones, or trace of lung or air-bladder. We next part company with those having the air-bladder a veritable lung, and those with an ancient type of paired fins, a jointed axis fringed with rays, and those having the palate still forming the upper jaw. We have finally left only those having fish-jaws, fish-fins, and in general the structure of the modern fish. For all these in all their variety, as a class or subclass, the name Actinopteri, or Actinopterygii, suggested by Professor Cope, is now generally adopted. The shorter form, Actinopteri, being equally correct is certainly preferable. This term (ακτίς, ray; πτερόν or πτερύξ, fin) refers to the structure of the paired fins. In all these fishes the bones supporting the fin-rays are highly specialized and at the same time concealed 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 parallel with it is the irregularly formed hypocoracoid. Attached to them is a row of bones, the actinosts, or pterygials, short, often hour-glass-shaped, which actually support the fin-rays. In the more specialized forms, or Teleosts, the actinosts are few (four to six) in number, but in the more primitive types, or Ganoids, they may remain numerous, a reminiscence of the condition seen in the Crossopterygians, and especially in Polypterus. Other variations may occur; the two coracoids sometimes are imperfect or specially modified, the upper sometimes without a foramen, and the actinosts may be distorted in form or position.
=The Series Ganoidei.=—Among the lower Actinopteri many archaic traits still persist, and in its earlier representatives the group approaches closely to the Crossopterygii, although no forms actually intermediate are known either living or fossil. The great group of Actinopteri may be divided into two series or subclasses, the Ganoidei, or Chrondrostei, containing those forms, mostly extinct, which retain archaic traits of one sort or another, and the Teleostei, or bony fishes, in which most of the primitive characters have disappeared. Doubtless all of the Teleostei are descended from a ganoid ancestry.
Even among the Ganoidei, as the term is here restricted, there remains a very great variety of form and structure. The fossil and existing forms do not form continuous series, but represent the tips and remains of many diverging branches perhaps from some Crossopterygian central stock. The group constitutes at least three distinct orders and, as a whole, does not admit of perfect definition. In most but not all of the species the tail is distinctly and obviously heterocercal, the lack of symmetry of the tail in some Teleosts being confined to the bones and not evident without dissection. Most of the Ganoids have the skeleton still cartilaginous, and in some it remains in a very primitive condition. Usually the Ganoids have an armature of bony plates, diamond-shaped, with an enamel like that developed 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 with the 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 spiral valve of the intestines found in the more archaic types of fishes. But traces of some or all of these structures are found in some bony fishes, and their presence in the Ganoids by no means justifies the union of the Ganoids with the sharks, Dipnoans, and Crossopterygians to form a great primary class, Palæichthyes, as proposed by Dr. Günther. Almost every form of body may be found among the Ganoids. In the Mesozoic seas these fishes were scarcely less varied and perhaps scarcely less abundant than the Teleosts in the seas of to-day. They far exceed the Crossopterygians in number and variety of forms. Transitional forms connecting the two groups are thus far not recognized. So far as fossils show, the characteristic actinopterous fin with its reduced and altered basal bones appeared at once without intervening gradations.
The name Ganoidei (γάνος, brightness; εἶδος, resemblance), alluding to the enameled plates, was first given by Agassiz to those forms, mostly extinct, which were covered with bony scales or hard plates of one sort or another. As the term was originally defined, mailed catfishes, sea-horses, Agonidæ, Arthrodires, Ostracophores, and other wholly unrelated types were included with the garpikes and sturgeons as Ganoids. Most of these intruding forms among living fishes were eliminated by Johannes Müller, who recognized the various archaic characters common to the existing forms after the removal of the mailed Teleosts. Still later Huxley separated the Crossopterygians as a distinct group, while others have shown that the Ostracophori and Arthrodira should be placed far from the garpike in systematic classification. Cope, Woodward, Hay, and others have dropped the name Ganoid altogether as productive of confusion through the 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 convenient to retain it. As an adjective "ganoid" is sometimes used as descriptive of bony plates or enameled scales, some-in the sense of archaic, as applied to fishes.
=Are the Ganoids a Natural Group?=—Several writers have urged that the Ganoidei, even as thus restricted, should not be considered as a natural group, whether subclass, order, or group of orders. The reasons for this view in brief are the following:
1. The group is heterogeneous. The Amiidæ differ more from the other Ganoids than they do from the herring-like Teleosts. The garpikes, sturgeons, paddle-fishes likewise diverge widely from each other and from the Palæoniscidæ and the Platysomidæ. Each of the living families represents the residue or culmination of a long series, in some 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, the spiral valve in the intestine, the heterocercal tail) are all possessed 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 urged that 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 soft-rayed fishes, or that from fishes with a duct to the air-bladder to those without such duct.
Admitting all this, it is nevertheless natural and convenient to retain the Ganoidei (or Chrondrostei if the older name be discarded on account of the many meanings attached to it) as a group equivalent to that of Teleostei within the class or subclass of Actinopteri. It comprises the transitional forms between the Crossopterygii and the bony fishes, and its members are especially characteristic of the Mesozoic age, ranging from the Devonian to the present era.
Of the extensive discussion relating to this important question we may quote two arguments for the retention of the subclass of Ganoids, the first by Francis M. Balfour and William Kitchen Parker, the second from the pen of Theodore Gill.
Balfour and Parker ("Structure and Development of Lepidosteus," pp. 430-433) thus discuss the
=Systematic Position of Lepidosteus.=—"Alexander Agassiz concludes his memoir on the development of Lepidosteus by pointing out that in spite of certain affinities in other directions this form is 'not so far removed from the bony fishes as has been supposed.' Our own observations go far to confirm Agassiz's opinion.
"Apart from the complete segmentation, the general development of Lepidosteus is strikingly Teleostean. In addition to the general Teleostean features of the embryo and larva, which can only be appreciated by those who have had an opportunity of practically working at the subject, we may point to the following developmental features[2] as indicative of Teleostean affinities:
"(1) The formation of the nervous system as a solid keel of the epiblast.
"(2) The division of the epiblast into a nervous and epidermic stratum.
"(3) The mode of development of the gut.
"(4) The mode of development of the pronephros; though the pronephros of Lepidosteus has primitive characters not retained by Teleostei.
"(5) The early stages in the development of the vertebral column.
Footnote 2:
The features enumerated above are not in all cases confined to Lepidosteus and Teleostei, but are always eminently characteristic of the latter.
"In addition to these, so to speak, purely embryonic characters there are not a few important adult characters:
"(1) The continuity of the oviducts with the genital glands.
"(2) The small size of the pancreas, and the presence of numerous so-called pancreatic cæca.
"(3) The somewhat coiled small intestine.
"(4) Certain characters of the brain, e.g., the large size of the cerebellum; 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:
"(1) The character of the truncus arteriosus.
"(2) The fact of the genital ducts joining the ureters.
"(3) The presence of vasa efferentia in the male carrying the semen from the testes to the kidney, and through the tubules of the latter into the kidney-duct.
"(4) The presence of a well-developed opercular gill.
"(5) The presence of a spiral valve; though this character may possibly break down with the extension of our knowledge.
"(6) The typical Ganoid characters of the thalamencephalon and the cerebral hemispheres.
"(7) The chiasma of the optic nerves.
"(8) The absence of a pecten, and presence of a vascular membrane between the vitreous humor and the retina.
"(9) The opisthocœlous form of the vertebræ.
"(10) The articulation of the ventral parts of the hæmal arches of the tail with the processes of the vertebral column.
"(11) The absence of a division of the muscles into dorso-lateral and ventro-lateral divisions.
"(12) The complete segmentation of the ovum.
"The list just given appears to us sufficient to demonstrate that Lepidosteus cannot be classed with the Teleostei; and we hold that Müller's view is correct, according to which Lepidosteus is a true Ganoid.
"The existence of the Ganoids as a distinct group has, however, recently been challenged by so distinguished an ichthyologist as Günther, and it may therefore be well to consider how far the group as defined by Müller is a natural one for living forms, and how far recent researches enable us to improve upon Müller's definitions. In his classical memoir the characters of the Ganoids are thus shortly stated:
"'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 row of spinous plates or splints. The caudal fin embraces occasionally in its upper lobe the end of the vertebral column, which may be prolonged to the end of the upper lobe. Their double nasal openings resemble those of Teleostei. The gills are free, and lie in a branchial cavity under an operculum, like those of Teleostei. Many of them have an accessory organ of respiration, in the form of an opercular gill, which is distinct from the pseudobranch, and can be present together with the latter; many also have spiracles like Elasmobranchii. They have many valves in the stem of the aorta like the latter, also a muscular coat in the stem of the aorta. Their ova are transported from the abdominal cavity by oviducts. Their optic nerves do not cross each other. The intestine is often provided with a spiral valve, like Elasmobranchii. They have a swimming-bladder with a duct, like many Teleostei. Their pelvic fins are abdominal.
"'If we include in a definition only those characters which are invariable, the Ganoids may be shortly defined as being those fish with numerous valves to the stem of the aorta, which is also provided with a muscular coat, with free gills, and an operculum, and with abdominal pelvic fins.'
"To these distinctive characters he adds, in an appendix to his paper, the presence of the spiral valve, and the absence of a processus falciformis and a choroid gland.
"To the distinctive set of characters given by Müller we may probably add the following:
"(1) Oviducts and urinary ducts always unite, and open by a common urogenital aperture behind the anus.
"(2) Skull hyostylic.
"(3) Segmentation complete in the types so far investigated, though perhaps Amia may be found to resemble the Teleostei in this particular.
"(4) A pronephros of the Teleostean type present in the larva.
"(5) Thalamencephalon very large and well developed.
"(6) The ventricle in the posterior part of the cerebrum is not divided behind into lateral halves, the roof of the undivided part being extremely thin.
"(7) Abdominal pores always present.
"The great number of characters just given are amply sufficient to differentiate the Ganoids as a group; but, curiously enough, the only characters, amongst the whole series which have been given, which can be regarded as peculiar to the Ganoids are (1) the characters of the brain, and (2) the fact of the oviducts and kidney-ducts uniting 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 the different members of this great group.
"At the same time, the only group with which existing Ganoids have close affinities is the Teleostei. The points they have in common with the Elasmobranchii are merely such as are due to the fact that both retain numerous primitive vertebrate characters,[3] and the gulf which really separates them is very wide.
Footnote 3:
As instances of this we may cite (1) the spiral valve; (2) the frequent presence of a spiracle; (3) the frequent presence of a communication between the pericardium and the body-cavity; (4) the heterocercal tail.
"There is again no indication of any close affinity between the 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-bladder into a true lung, the highly specialized character of their limbs,[4] their peculiar autostylic skulls, the fact of their ventral nasal openings leading directly into the mouth, their multi-segmented bars (interspinous bars) directly prolonged from the neural and hæmal and supporting the fin-rays of the unpaired dorsal 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 distinctly separated from the Ganoids.
Footnote 4:
Vide F. M. Balfour, "On the Development of the Skeleton of the Paired Fins of Elasmobranchs," Proc. Zool. Soc., 1881.
"No doubt the Chondrostean Ganoids are nearly as far removed from the Teleostei as from the Dipnoans, but the links uniting these Ganoids with the Teleostei have been so fully preserved in the existing fauna of the globe that the two groups almost 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 uniting the Teleostei and Ganoids, or rather constituting the Teleostei into one of the subgroups of the Ganoids, equivalent to the Chondrostei. We do not recommend such an arrangement, which in view of the great preponderance of the Teleostei amongst living fishes would be highly inconvenient, but the step from Amia to the Teleostei is certainly not so great as that from the Chondrostei to Amia, and is undoubtedly less than that from the Selachii to the Holocephali."
=Gill on the Ganoids as a Natural Group.=—Dr. Gill observes ("Families of Fishes," 1872): "The name Ganoides (or Ganiolepedoti) was originally framed by Prof. Agassiz as an ordinal term for fishes having the scales (when present) angular and covered with enamel; and in the group so characterized were combined the Ganoids of subsequent authors as well as the Teleostean orders Plectognathi, Lophobranchii, and Nematognathi, and (subsequently) the genus Sudis (Arapaima), the last being regarded as a Cœlacanth. The group has not been accepted with these limits or characters.
"But the researches of Prof. Johannes Müller on the anatomy and classification of the fishes culminated at length in his celebrated memoirs on those fishes for which he retained the ordinal name Ganoidei; those memoirs have left an impression on ichthyology perhaps more decided than made by any other contributions to science, and that published in extenso will ever be classical; numerous as have been the modifications since introduced into the system, no forms except those recognized by Müller (unless it be Dipnoi) have been interjected since among 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 Müller to be peculiar to the teleostomous forms combined therein are problematical, and only inferentially supposed to be common to the extinct Ganoids so called, and, finally, such objections couched in too strong language have culminated in the assertion that the characters in question are actually shared by other physostome fishes.
"No demonstration, however, has been presented as yet that any physostome fishes do really have the optic chiasma and multivalvular bulbus arteriosus, and the statement to the contrary seems to have been the result of a venial misapprehension of Prof. Kner's statements, or the offspring of impressions left on the memory by his assertions, in forgetfulness of his exact words.
"But Prof. Kner, in respect to the anatomical characters referred to, merely objects: (1) that they are problematical, are not confirmable for the extinct types, and were probably not existent in certain forms that have been referred to the Ganoids; (2) the difference in number of the valves of the bulbus arteriosus among recent Ganoids is so great as to show the unreliability of the character; (3) a spiral valve is developed in the intestine 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 positive 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 character, has long been conceded, and in this case only have the forms that prove the failure been referred to; in the 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 objections must be met as if they were not known to exist.
"(1) 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 it be urged that any characters that have not been or cannot be directly confirmed are problematical in the case of all other groups (e.g., mammals), and it can only be replied that the coordination of parts has been so invariably verified that all probabilities are in favor of similar coordination in any given case.
"(2) There is doubtless considerable difference in the number of valves of the bulbus arteriosus among the various Ganoids, and even among the species of a single family (e.g., Lepidosteidæ), but the character of Ganoids lies not in the number, more or less, but in the greater number and relations (in contradistinction to the opposite pair of the Teleosts) in conjunction with the development of a bulbus arteriosus. In no other forms of Teleostomes have similar relations and structures been yet demonstrated.
"(3) The failure of the spiral intestinal valve has already been conceded, and no great stress has ever been laid on the character.
"(4) The chiasma of the optic nerves is so common to all the known Ganoids, and has not been found in those forms (e.g., Arapaima, Osteoglossum, and Clupeiform types) agreeing with typical physostome Teleosts in the skeleton, heart, etc., but which at the same time simulate most certain Ganoids (e.g., Amia) in form.
"Therefore, in view of the evidence hitherto obtained, the arguments against the validity of title, to natural association, of the Ganoids, have to meet the positive evidence of the coordinations noted; the value of such characteristics and coordinations can only be affected or destroyed by the demonstration that in all other respects there is (1) very close agreement of certain of the constituents of the subclass with other forms, and (2) inversely proportionate dissimilarity of those forms from any (not all) other of the Ganoids, and consequently evidence ubi plurima nitent against the taxonomic value of the characters employed for distinction.
"And it is true that there is a greater superficial resemblance between the Hyoganoids (Lepisosteus, Amia, etc.) and ordinary physostome Teleosts than between the former and the other orders of Ganoids, but it is equally true that they agree in other respects than in the brain and heart with the more generalized Ganoids. They all have, for example, (1) the paraglenal elements undivided (not disintegrated into hypercoracoid, hypocoracoid, and mesocoracoid); (2) a humerus (simple or divided, that is, differentiated into metapterygium and mesopterygium); and (3) those with ossified skeletons agree in the greater number of elements in the lower jaw. Therefore, until these coordinates fail, it seems advisable to recognize the Ganoids as constituents 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 before the mind the characters in question, it appears also advisable to designate the series, until further discovery, as a subclass.
"But it is quite possible that among some of the generalized Teleosts at least traces of some of the characters now considered to be peculiar to the Ganoids may be discovered. In anticipation of such a possibility, the author had at first discarded the subclass, recognizing the group only as one of the 'superorders' of the Teleostomes, but reconsideration convinces him of the propriety of classification representing known facts and legitimate inferences rather than too much anticipation.
"It is remembered that all characters are liable to fail with increasing knowledge, and the distinctness of groups are but little more than the expressions of our want of knowledge of the intermediate forms; it may in truth be said that ability to segregate a class into well-defined groups is in ratio to our ignorance of all the terms."
II. THE GANOIDS—Continued
=CLASSIFICATION of Ganoids.=—The subdivision of the series of Ganoidei into orders offers great difficulty from the fact of the varying relationships of the members of the group and the fact that the great majority of the species are known only from broken skeletons preserved in the rocks. It is apparently easy to separate those with cartilaginous skeletons from those with these bones more or less ossified. It is also easy to separate those with bony scales or plates from those 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 Lysopteri (λυσός, loose; πτερόν, fin) by Cope, Heterocerci by Zittel and Eastman, and the "ascending series of Chondrostei" by Woodward, we find the nearest approach to the Chondropterygians. In this order the arches of the vertebræ are more or less ossified, the body is more or less short and deep, covered with bony dermal plates. The opercular apparatus is well developed, with numerous branchiostegals. Infraclavicles are present, 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.
=The Palæoniscidæ.=—The numerous genera of this order are referred to three families, the Palæoniscidæ, Platysomidæ, and Dictyopygidæ; a fourth family, Dorypteridæ, of uncertain relations, being also tentatively recognized. The family of Palæoniscidæ 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 have the body elongate and provided with one short dorsal fin. The tail is heterocercal and the body covered with rhombic plates. Fulcra or rudimentary spine-like scales are developed on the upper edge of the caudal fin in most recent Ganoids, and often the back has a median row of undeveloped scales. A multitude of species and genera are recorded. A typical form is the genus Palæoniscum,[5] with many species represented in the rocks of various parts of the world. The longest known species is Palæoniscum frieslebenense from the Permian of Germany and England. Palæoniscum magnum, sixteen inches long, occurs in the Permian of Germany. From Canobius, the most primitive genus, to Coccolepis, the most modern, is a continuous series, the suspensorium of the lower jaw becoming more oblique, the basal bones of the dorsal fewer, the dorsal extending farther forward, and the scales more completely imbricate. Other prominent genera are Amblypterus, Eurylepis, Cheirolepis, Rhadinichthys, Pygopterus, Elonichthys, Ærolepis, Gyrolepis, Myriolepis, Oxygnathus, Centrolepis, and Holurus.
Footnote 5:
This word is usually written Palæoniscus, but Blainville, its author (1818), chose the neuter form.
=The Platysomidæ.=—The Platysomidæ are different in form, the body being deep and compressed, often diamond-shaped, with very long dorsal and anal fins. In other respects they are very similar to the Palæoniscidæ, the osteology being the same. The Palæoniscidæ were rapacious fishes with sharp teeth, the Platysomidæ less active, and, from the blunter teeth, probably feeding on small animals, as crabs and snails.
The rhombic enameled scales are highly specialized and held together as a coat of mail by peg-and-socket joints. The most extreme form is Platysomus, with the body very deep. Platysomus gibbosus and other species occur in the Permian rocks of Germany. Cheirodus is similar to Platysomus, but without ventral fins. Eurynotus, the most primitive genus, is remarkable for its large pectoral fins. Eurynotus crenatus occurs in the Subcarboniferous of Scotland. Other genera are Mesolepis, Globulodus, Wardichthys, and Cheirodopsis.
Some of the Platysomidæ have the interneural spines projecting through the skin before the dorsal fin. This condition is found also in certain bony fishes allied to the Carangidæ.
=The Dorypteridæ.=—Dorypterus hoffmani, the type of the singular Palæozoic family of Dorypteridæ, with thoracic or sub-jugular many-rayed ventrals, is Stromateus-like to all appearance, with distinct resemblances to certain Scombroid forms, but with a heterocercal tail like a ganoid, imperfectly ossified back-bone, and other very archaic characters. The body is apparently scaleless, unlike the true Platysomidæ, in which the scales are highly developed. A second species, Dorypterus althausi, also from the German copper shales, has been described. This species has lower fins than Dorypterus hoffmani, but may be the adult of the same type. Dorypterus is regarded by Woodward as a specialized offshoot from the Platysomidæ. The many-rayed ventrals and the general form of the body and fins suggest affinity with the Lampridæ.
=Dictyopygidæ.=—In the Dictyopygidæ (Catopteridæ), the body is gracefully elongate, less compressed, the heterocercal tail is short and abruptly turned upwards, the teeth are sharp and usually hooked, and the bony plates well developed. Of this group two genera are recognized, each containing numerous species. In Redfieldius (= Catopterus Redfield, not of Agassiz) the dorsal is inserted behind the anal, while in Dictyopyge this is not the case. Redfieldius gracilis and other species are found in the Triassic of the Connecticut River. Dictyopyge macrura is found in the same region, and Dictyopyge catoptera and other species in Europe.
=Order Chondrostei.=—The order Chondrostei (χόνδρος, cartilage; ὀστέον, bone), as accepted by Woodward, is characterized 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 regular series and the rays are more numerous than the supporting elements. The shoulder-girdle has a pair of infraclavicular plates. The pelvic fins have well-developed baseosts. 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 modern degenerate forms known as sturgeons and perhaps the paddle-fishes, which are apparently derived from fishes with rhombic enameled scales. The species extend from the Upper Carboniferous to the present time, being most numerous in the Triassic.
At this point in Woodward's system diverges a descending series, characterized as a whole by imperfect squamation and elongate form, this leading through the synthetic type of Chondrosteidæ to the modern sturgeon and paddle-fish, which are regarded as degenerate types.
The family of Saurorhynchidæ contains pike-like forms, with long 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 of the skull form a continuous shield. The opercular apparatus is much reduced, and there are no branchiostegals. The fins are all small, without fulcra, and the skin has isolated longitudinal series of bony scutes, but is not covered with continuous scales. The principal genus is Saurorhynchus (= Belonorhynchus; the former being the earlier name) from the Triassic. Saurorhynchus acutus from the English Triassic is the best known species.
The family of Chondrosteidæ includes the Triassic precursors of the sturgeons. The general form is that of the sturgeon, but the body is scaleless except on the upper caudal lobe, and there are no plates on the median line of the skull. The opercle and subopercle are present, the jaws are toothless, and there are a few well-developed caudal rays. The caudal has large fulcra. The single well-known species of this group, Chondrosteus acipenseroides, is found in the Triassic rocks of England and reaches a length of about three feet. It much resembles a modern sturgeon, though differing in several technical respects. Chondrosteus pachyurus is based on the tail of a species of much larger size and Gyrosteus mirabilis, also of the English Triassic, is known from fragments of fishes which must have been 18 to 20 feet in length.
The sturgeons constitute the recent family of Acipenseridæ, characterized by the prolonged snout and toothless jaws and the presence of four barbels below the snout. In the Acipenseridæ there are no branchiostegals and a median series of plates is present on the head. The body is armed with five rows of large bony bucklers,—each often with a hooked spine, sharpest in the young. Besides these, rhombic plates are developed on the tail, besides large fulcra. The sturgeons are the youngest of the Ganoids, not occurring before the Lower Eocene, one species, Acipenser toliapicus 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 of the species belong to the genus Acipenser, which abounds in all the rivers and seas in which salmon are found. Some of the smaller species spend their lives in the rivers, ascending smaller streams to spawn. Other sturgeons are marine, ascending fresh waters only for a moderate distance in the spawning season. They range in length from 2½ to 30 feet.
All are used as food, although the flesh is rather coarse and beefy. From their large size and abundance they possess great economic value. The eggs of some species are prepared as caviar.
The sturgeons are sluggish, clumsy, bottom-feeding fish. The mouth, underneath the long snout, is very protractile, sucker-like, and without teeth. Before it on the under side of the snout are four long feelers. Ordinarily the sturgeon feeds on mud and snails with other small creatures, but I have seen large numbers of Eulachon (Thaleichthys) in the stomach of the Columbia River sturgeon (Acipenser transmontanus). This fish and the Eulachon run in the Columbia at the same time, and the sucker-mouth of a large sturgeon will draw into it numbers of small fishes who may be unsuspiciously engaged in depositing their spawn. In the spawning season in June these clumsy fishes will often leap wholly out of the water in their play. The sturgeons have a rough skin besides five series of bony plates which change much with age and which in very old examples are sometimes lost or absorbed in the skin. The common sturgeon of the Atlantic on both shores is Acipenser sturio. Acipenser huso and numerous other species are found in Russia and Siberia. The great sturgeon of the Columbia is Acipenser transmontanus, and the great sturgeon of Japan Acipenser kikuchii. Smaller species are found farther south, as in the Mediterranean and along the Carolina coast. Other small species abound in rivers and lakes. Acipenser rubicundus is found throughout the Great Lake region and the Mississippi Valley, never entering the sea. It is four to six feet long, and at Sandusky, Ohio, in one season 14,000 sturgeons were taken in the pound nets. A similar species, Acipenser mikadoi, is abundant and valuable in the streams of northern Japan.
In the genus Acipenser the snout is sharp and conical, and the shark-like spiracle is still retained.
The shovel-nosed sturgeon (Scaphirhynchus platyrhynchus) has lost the spiracles, the tail is more slender, its surface wholly bony, and the snout is broad and shaped like a shovel. The single species of Scaphirhynchus abounds in the Mississippi Valley, a fish more interesting to the naturalist than to the fisherman. It is the smallest of our sturgeons, often taken in the nets in large numbers.
In Scaphirhynchus the tail is covered by a continuous coat of mail. In Kessleria[6] fedtschenkoi, rossikowi, and other Asiatic species the tail is not mailed.
Footnote 6:
These species have also been named Pseudoscaphirhynchus. Kessleria is the earlier name, left undefined by its describer, although the type was indicated.
=Order Selachostomi: the Paddle-fishes.=—Another type of Ganoids, allied to the sturgeons, perhaps still further degenerate, is that of the paddle-fishes, called by Cope Selachostomi (σέλαχος, shark; στόμα, mouth). This group consists of a single family, Polyodontidæ, having apparently little in common with the other Ganoids, and in appearance still more suggestive of the sharks. The common name of paddle-fishes is derived from the long flat blade in which the snout terminates. This extends far beyond the mouth, is more or less sensitive, and is used to stir up the mud in which are found the minute organisms on which the fish feeds. Under the paddle are four very minute barbels corresponding to those of the sturgeons. The vernacular names of spoonbill, duckbill cat, and shovel-fish are also derived from the form of the snout. The skin is nearly smooth, the tail is heterocercal, the teeth are very small, and a long fleshy flap covers the gill-opening. The very long and slender gill-rakers serve to strain the food (worms, leeches, water-beetles, crustaceans, and algæ) from the muddy waters from which they are taken. The most important part of this diet consists of Entomostracans. The single American species, Polyodon spathula, abounds through the Mississippi Valley in all the larger streams. It reaches a length of three or four feet. It is often taken in the nets, but the coarse tough flesh, like that of our inferior catfish, is not much esteemed. In the great rivers of China, the Yangtse and the Hoang Ho, is a second species, Psephurus gladius, with narrower snout, fewer gill-rakers, and much coarser fulcra on the tail. The habits, so far as known, are much the same.
Crossopholis magnicaudatus of the Green River Eocene shales is a primitive member of the Polyodontidæ. Its rostral blade is shorter than that of Polyodon, and the body is covered with small thin scales, each in the form of a small grooved disk with several posterior denticulations, arranged in oblique series but not in contact. The scales are quadrate in form, and more widely separated anteriorly than posteriorly. As in Polyodon, the teeth are minute and there are no branchiostegals. The squamation of this fish shows that Polyodon as well as Acipenser may have sprung from a type having rhombic scales. The tail of a Cretaceous fish, Pholidurus disjectus from the Cretaceous of Europe, has been referred with doubt to this family of Polyodontidæ.
=Order Pycnodonti.=—In the extinct order Pycnodonti, as recognized by Dr. O. P. Hay, the notochord is persistent and without ossification, the body is very deep, the teeth are always blunt, the opercular apparatus is reduced, the dorsal fin many-rayed, and the fins without fulcra. The scales are rhombic, but are sometimes wanting, at least on the tail. Many genera and species of Pycnodontidæ are described, mostly from Triassic and Jurassic rocks of Europe. Leading European genera are Pycnodus, Typodus (Mesodon), Gyrodus, and Palæobalistum. The numerous American species belong to Typodus, Cœlodus, Pycnodus, Hadrodus, and Uranoplosus. These forms have no affinity with Balistes, although there is some resemblance in appearance, which has suggested the name of Palæobalistum.
Woodward places these fishes with the Semionotidæ and Halecomorphi in his suborder of Protospondyli. It seems preferable, however, to consider them as forming a distinct order.
=Order Lepidostei.=—We may place, following Eastman's edition of Zittel, the allies and predecessors of the garpike in a single order, for which Huxley's name Lepidostei may well be used. In this group the notochord is persistent, and the vertebræ are in various degrees of ossification and of different forms. The opercles are usually complete, the branchiostegals present, and there is often a gular plate. There is no infraclavicle and the jaws have sharp teeth. The fins have fulcra, and the supports of the fins agree in number with the rays. The tail is more or less heterocercal. The scales are rhombic, arranged in oblique series, which are often united above and below with peg-and-socket articulations. This group contains among recent fishes only the garpikes (Lepisosteus). They are closely allied to the Palæoniscidæ, but the skeleton is more highly ossified. On the other hand they approach very closely to the ancestors of the bowfin, Amia. One genus, Acentrophorus, appears in the Permian; the others are scattered through Mesozoic and Tertiary rocks, the isolated group of gars still persisting. In the gars the vertebræ are concavo-convex, with ball-and-socket joints. In the others the vertebræ are incomplete or else double-concave, as in fishes generally.
For the group here called Lepidostei numerous other names have been used corresponding wholly or in part. Rhomboganoidea of Gill covers nearly the same groups; Holostei of Müller and Hyoganoidea of Gill include the Halecomorphi also; Ginglymodi of Cope includes the garpikes only, while Ætheospondyli of Woodward includes the Aspidorhynchidæ and the garpikes.
The Semionotidæ (Stylodontidæ) are robust-bodied Ganoids, having the vertebræ developed as rings, the jaws with several rows of teeth, those of the outer row styliform.
Semionotus bergeri is a well-known species, with the body moderately elongate. Semionotus agassizi and many other species occur in the Triassic of the Connecticut valley and in New Jersey. The body is very deep in the related genus Dapedium, and the head is covered with strong bony plates. Dapedium politum is a well-known species of the English Triassic. Tetragonolepis (Pleurolepis) is a similar form, very deep and compressed, with strong, firm scales.
In the extinct family of Lepidotidæ the teeth are conical or chisel-shaped, while blunt or molar teeth are on the inside of the mouth, which is small, and the suspensorium of the mandible is vertical or inclined forward. The body is robust-fusiform, covered with rhomboid scales; the vertebræ form rings about the notochord; the teeth are either sharp or blunt. The dorsal fin is short, with large fulcra.
The best known of the numerous genera are Lepidotes, rather elongate in body, with large, blunt teeth. Of the many species of Lepidotes, Lepidotes elvensis abounds in the English and German Triassic, and Lepidotes minor in the English Triassic. Another well-known European species is Lepidotes mantelli.
The Isopholidæ (Eugnathidæ) differ from the families last named in the large pike-like mouth with strong teeth. The mandibular suspensorium is inclined backwards. The body is elongate, the vertebræ forming incomplete rings; the dorsal fin is short with large fulcra.
Isopholis dentosus is found with numerous other species in the British Triassic. Caturus furcatus is especially characteristic of Triassic rocks in Germany. Ptycholepis marshi occurs in the Connecticut valley.
The Macrosemiidæ are elongate fishes with long dorsal fin, the numerous species being found in the Triassic, Jurassic, and Cretaceous of Europe. Macrosemius rostratus has a very high, continuous dorsal. Macropistius arenatus is found in the Cretaceous of Texas, the only American species known. Prominent European genera are Notagogus, Ophiopsis, and Petalopteryx.
Intermediate between the allies of the gars and the modern herrings is the large extinct family of Pholidophoridæ, referred by Woodward to the Isospondyli, and by Eastman to the Lepidostei. These are small fishes, fusiform in shape, chiefly of the Triassic and Jurassic. The fins are fringed with fulcra, the scales are ganoid and rhombic, and the vertebræ reduced to rings. The mouth is large, with small teeth, and formed as in the Isospondyli. The caudal is scarcely heterocercal.
Of Pholidophorus, with scales joined by peg-and-socket joints and uniform in size, there are many species. Pholidophorus latiusculus and many others are found in the Triassic of England and the Continent. Pholidophorus americanus occurs in the Jurassic of South Dakota. Pleuropholis, with the scales on the lateral line, which runs very low, excessively deepened, is also widely distributed. I have before me a new species from the Cretaceous rocks near Los Angeles. The Archæomænidæ differ from Pholidophoridæ in having cycloid scales. In both families the vertebræ are reduced to rings about the notochord. From fishes allied to the Pholidophoridæ the earliest Isospondyli are probably descended.
In the Aspidorhynchidæ the snout is more or less produced, the mandible has a distinct presymphysial bone, the vertebræ are double-concave or ring-like, and the fins are without fulcra. This family constitutes the suborder Ætheospondyli. In form these fishes resemble Albula and other modern types, but have mailed heads and an ancient type of scales. Two genera are well known, Aspidorhynchus and Belonostomus. Aspidorhynchus acutirostris reaches a length of three feet, and is found in the Triassic lithographic stone of Bavaria. Other species occur in rocks of Germany and England.
Belonostomus has the snout scarcely produced. Belonostomus sphyrænoides is the best known of the numerous species, all of the Triassic, Jurassic, and Cretaceous.
=Family Lepisosteidæ.=—The family of Lepisosteidæ, constituting the suborder Ginglymodi (γιγγλυμός, hinge), is characterized especially by the form of the vertebræ.
These are opisthocœlian, convex in front and concave behind, as in reptiles, being connected by ball-and-socket joints. The tail is moderately heterocercal, less so than in the Halecomorphi, and the body is covered with very hard, diamond-shaped, enameled scales in structure similar to that of the teeth. A number of peculiar characters are shown by these fishes, some of them having often been regarded as reptilian traits. Notable features are the elongate, crocodile-like jaws, the upper the longer, and both armed with strong teeth. The mandible is without presymphysial bone. The fins are small with large fulcra, and the scales are nearly uniform in size.
All the species belong to a single family, Lepisosteidæ, which includes the modern garpikes and their immediate relatives, some of which occur in the early Tertiary. These voracious fishes are characterized by long and slender cylindrical bodies, with enameled scales and mailed heads and heterocercal tail. The teeth are sharp and unequal. The skeleton is well ossified, and the animal itself is extremely voracious. The vertebræ, reptile-like, are opisthocœlian, that is, convex in front, concave behind, forming ball-and-socket joints. In almost all other fishes they are amphicœlian or double-concave, the interspace filled with gelatinous substance. The recent species, and perhaps all the extinct species also, belong to the single genus Lepisosteus (more correctly, but also more recently, spelled Lepidosteus). Of existing forms there are not many species, three to five at the most, and they swarm in the lakes, bayous, and sluggish streams from Lake Champlain to Cuba and along the coast to Central America. The best known of the species is the long-nosed garpike, Lepisosteus osseus, which is found throughout most of the Great Lake region and the Mississippi Valley, and in which the long and slender jaws are much longer than the rest of the head. The garpike frequents quiet waters and is apparently of sleepy habit. It often lies quiet for a long time, carried around and around by the eddies. It does not readily take the hook and seldom feeds in the aquarium. It feeds on crayfishes and small fishes, to which it is exceedingly destructive, as its bad reputation indicates. Fishermen everywhere destroy it without mercy. Its flesh is rank and tough and unfit even for dogs.
In the young garpike the caudal fin appears as a second dorsal and anal, the filamentous tip of the tail passing through and beyond it.
The short-nosed garpike, Lepisosteus platystomus, is generally common throughout the Mississippi Valley. It has a short broad snout like the alligator-gar, but seldom exceeds three feet in length. In size, color, and habits it agrees closely with the common gar, differing only in the form of the snout. The form is subject to much variation, and it is possible that two or more species have been confounded.
The great alligator-gar, Lepisosteus tristœchus, reaches a length of twenty feet or more, and is a notable inhabitant of the streams about the Gulf of Mexico. Its snout is broad and relatively wide, and its teeth are very strong. It is very destructive to all sorts of food-fishes. Its flesh is worthless, and its enameled scales resist a spear or sometimes even shot. It breathes air to a certain extent by its lungs, but soon dies in foul water, not having the tenacity of life seen in Amia.
=Embryology of the Garpike.=—Mr. Alexander Agassiz has given an account of the embryology of the garpike, of which the following is an abstract:
"The garpike comes up the St. Lawrence in May, lays its eggs about the 20th, and then disappears. The eggs are large, viscous, stick fast in an isolated way to whatever they fall upon, and look much like those of toads, having a large outer membrane and a small yolk. Artificial fecundation failed, but about 500 naturally-laid eggs were secured, of which all but 30 perished through mold. The young began to hatch in six days. Out of 30 young hatched, 27 lived until the 15th of July. Connection with the sharks appears in the similarity of the branchial arches and by the presence of the lateral fold in which the pectoral fins are formed; the way the tail is developed is very like that of the bony fishes. Among the Ganoids it appears, as well as in ordinary fishes, the dorsal cord is straight at first, then assumes a slightly upward curve at the extremity, when finally there appears the beginning of a lobe underneath, pointing to a complete heterocercal tail. All this is as in the bony fishes, but this is the permanent condition of the garpike, while in the bony fishes the extremity of the dorsal cord becomes extinct. The mode of development of the pectoral lobe (very large in this species) furnishes another resemblance. In the brain, and in the mode of formation of the gills, a likeness to the sharks is noticeable. The young garpikes move very slowly, and seem to float quietly, save an exceedingly rapid vibration of the pectorals and the tip of the tail. They do not swim about much, but attach themselves to fixed objects by an extraordinary horseshoe-shaped ring of sucker-appendages about the mouth. These appendages remain even after the snout has become so extended that the ultimate shape is hinted at; and furthermore, it is a remnant of this feature that forms the fleshy bulb at the end of the snout in the adult. The investigations thus far show that the young garpike has many characteristics in common with the sharks and skates, but it is not so different from the bony fishes as has been supposed."
=Fossil Garpikes.=—A number of fossil garpikes, referred by Cope to the genus Clastes and by Eastman and Woodward to Lepidosteus, are found in the Eocene of Europe and America. The most perfect of these remains is called Lepisosteus atrox, upward of four feet long, as large as an alligator-gar, which the species much resembles. Although found in the Eocene, Dr. C. R. Eastman declares that "it has no positively archaic features. If we inquire into the more remote or pre-Eocene history of Lepidosteids, palæontology gives no answer. They blossom forth suddenly and fully differentiated at the dawn of the Tertiary, without the least clue to their ancestry, unheralded and unaccompanied by any intermediate forms, and they have remained essentially unchanged ever since."
Another fossil species is Lepisosteus fimbriatus, from the Upper Eocene of England. Scales and other fragments of garpikes are found in Germany, Belgium, and France, in Eocene and Miocene rocks. On some of these the nominal genera Naisia, Trichiurides, and Pneumatosteus are founded. Clastes, regarded by Eastman as fully identical with Lepisosteus, is said to have the "mandibular ramus without or with a reduced fissure of the dental foramen, and without the groove continuous with it in Lepisosteus. One series of large teeth, with small ones external to them on the dentary bone." Most of the fossil forms belong to Clastes, but the genus shows no difference of importance which will distinguish it from the ordinary garpike.
=Order Halecomorphi.=—To this order belong the allies, living or extinct, of the bowfin (Amia), having for the most part cycloid scales and vertebræ approaching those of ordinary fishes. The resemblance to the Isospondyli, or herring group, is indicated in the name (Halec, a herring; μορφή, form). The notochord is persistent, the vertebræ variously ossified. The opercles are always complete. The branchiostegals are broad and there is always a gular plate. The teeth are pointed, usually strong. There is no infraclavicle. Fulcra are present or absent. The supports of the dorsal and anal are equal in number to the rays. Tail heterocercal. Scales thin, mostly cycloid, but bony at base, not jointed with each other. Mandible complex, with well-developed splenial rising into a coronoid process, which is completed by a distinct coronoid bone. Pectoral fin with more than five actinosts; scales ganoid or cycloid. In the living forms the air-bladder is connected with the œsophagus through life; optic chiasma present; intestine with a spiral valve. This group corresponds to the Amioidei of Lütken and essentially to the Cycloganoidei of Gill. The Protospondyli (προτός, before; σπόνδυλος, vertebra) of Woodward contains essentially the same elements.
=Pachycormidæ.=—In the family of Pachycormidæ the notochord is persistent, the ethmoids and vomer fused and projecting between the maxillaries to form the prominent snout, the teeth large, the body fusiform, the dorsal short, with slender rays and few fulcra or none, and the scales are thin and rhombic. The numerous species are characteristic of the Triassic, Jurassic, and Cretaceous. In Sauropsis (longimana) the body is elongate, and the pectoral fins are large and sickle-shaped. Euthynotus has small fulcra. In Pachycormus (macropterus, esocinus, etc.) the form is robust and the ventral fins are wanting. In Hypsycormus ventrals are present, and the caudal deeply forked.
In the American family of Protosphyrænidæ the jaws are armed with very strong teeth, as in the Barracuda, which, however, the species do not resemble in other respects. Protosphyræna nitida, perniciosa, and numerous other extinct forms, some of them of large size, were voracious inhabitants of the Cretaceous seas, and are found fossil, especially in North Carolina and Kansas. Numerous species called Erisichthe and Pelecopterus are all referred by Hay to Protosphyræna. In this family the scapula and coracoids are ossified, and perhaps the vertebræ also, and, as Dr. Hay has recently suggested, the Protosphyrænidæ may really belong to the Isospondyli. In any event, they stand on the border-line between the most fish-like of the Ganoids and the most archaic of the bony fishes.
The Liodesmidæ (genus Liodesmus) are much like Amia, but the notochord is persistent, its sheath without ossification. Liodesmus gracilis and L. sprattiformis occur in the lithographic stones of Bavaria. Woodward places Liodesmus with Megalurus among the Amiidæ.
=The Bowfins: Amiidæ.=—The Amiidæ have the vertebræ more complete. The dorsal fin is many-rayed and is without distinct fulcra. The diamond-shaped enameled scales disappear, giving place to cycloid scales, which gradually become thin and membranous in structure. A median gular plate is developed between the branchiostegals. The tail is moderately heterocercal, and the head covered with a bony coat of mail.
The family of Amiidæ contains a single recent species, Amia calva, the only living member of the order Halecomorphi. The bowfin, or grindle, is a remarkable fish abounding in the lakes and swamps of the Mississippi Valley, the Great Lake region, and southward to Virginia, where it is known by the imposing but unexplained title of John A. Grindle. In the Great Lakes it is usually called "dogfish," because even the dogs will not eat it, and "lawyer," because, according to Dr. Kirtland, "it will bite at anything and is good for nothing when caught."
The bowfin reaches a length of two and one half feet, the male being smaller than the female and marked by an ocellated black spot on the tail. Both sexes are dark mottled green in color. The flesh of the species is very watery, pasty, much of the substance evaporating when exposed to the air. It is ill-flavored, and is not often used as food. The species is very voracious and extremely tenacious of life. Its well-developed lung enables it to breathe even when out of the water, and it will live in the air longer than any other fish of American waters, longer even than the horned pout (Ameiurus) or the mud-minnow (Umbra). As a game fish the grindle is one of the very best, if the angler does not care for the flesh of what he catches, it being one of the hardest fighters that ever took the hook.
The Amiidæ retain many of the Ganoid characters, though approaching more nearly than any other of the Ganoids to the modern herring tribe. For this reason the name Halecomorphi (shad-formed) was given to this order by Professor Cope. The gular plate found in Amia and other Ganoids reappears in the herring-like family of Elopidæ, which includes the tarpon and the ten-pounder.
Woodward unites the extinct genera called Cyclurus, Notæus, Amiopsis, Protamia, Hypamia, and Pappichthys with Amia. Pappichthys (corsoni, etc.), from the Wyoming Eocene, is doubtless a valid genus, having but one row of teeth in each jaw, and Amiopsis is also recognized by Hay. Woodward refers to Amia the following extinct species: Amia valenciennesi, from the Miocene of France; Amia macrocephala, from the Miocene of Bohemia; and Amia ignota, from the Eocene of Paris. Other species of Amia are known from fragments. Several of these are from the Eocene of Wyoming and Colorado. Some of them have a much shorter dorsal fin than that of Amia calva and may be generically different.
The genus Megalurus differs from Amia in the still shorter dorsal fin, less than one-third the length of the back. The body is elongate and much depressed. Megalurus lepidotus and several other species are found in the lithographic stones of Bavaria and elsewhere.
=The Oligopleuridæ.=—In the extinct family Oligopleuridæ the scales are cycloid, the bones of the head scarcely enameled, and the vertebræ well ossified. Fulcra are present, and the mouth is large, with small teeth. The genera are Oligopleurus, Ionoscopus, and Spathiurus, the species not very numerous and chiefly of the Cretaceous. Ionoscopus cyprinoides of the lithographic shales of Bavaria is a characteristic species.
From the three families last named, with the Pholidophoridæ, there is an almost perfect transition from the Ganoid fishes to teleosteans of the order of Isospondyli, the primitive order from which all other bony fishes are perhaps descended. The family of Leptolepidæ, differing from Oligopleuridæ in the absence of fulcra, is here placed with the Isospondyli, but it might about as well be regarded as Ganoid.
III. ISOSPONDYLI
=THE Subclass Teleostei, or Bony Fishes.=—The fishes which still remain for discussion constitute the great subclass or series of Teleostei (τελεός, true; οστέον, bone), or bony fishes. They lack wholly or partly the Ganoid traits, or show them only in the embryo. The tail is slightly, if at all, heterocercal; the actinosts of the pectoral fins are few and large, rarely over five in number, except among the eels; the fulcra disappear; the air-bladder is no longer cellular, except in very rare cases, nor does it assist in respiration. The optic nerves are separate, one running to each eye without crossing; the skeleton is almost entirely bony, the notochord usually disappearing entirely with age; the valves in the arterial bulb are reduced in number, and the spiral valve of the intestines disappears. Traces of each of the Ganoid traits may persist somewhere in some group, but as a whole we see a distinct specialization and a distinct movement toward the fish type, with the loss of characters distinctive of sharks, Dipnoans, and Ganoids. In a general way the skeleton of all Teleosts corresponds with that of the striped bass (see Figs. 22, 23, Vol. I), and the visceral anatomy is in all cases sufficiently like that of the sunfish (Fig. 16, Vol. I).
The mesocoracoid or precoracoid arch, found in all Ganoids, persists in the less specialized types of bony fishes, although no trace of it is found in the perch-like forms. With all this, there is developed among the bony fishes an infinite variety in details of structure. For this reason the Teleostei must be broken into many orders, and these orders are very different in value and in degrees of distinctness, the various groups being joined by numerous and puzzling intergradations.
=Order Isospondyli.=—Of the various subordinate groups of bony fishes, there can be no question as to which is most primitive in structure, or as to which stands nearest the orders of Ganoids. Earliest of the bony fishes in geological time is the order of Isospondyli (ἴσος, equal; σπόνδυλος, vertebra), containing the allies, recent or fossil, of the herring and the trout. This order contains those soft-rayed fishes in which the ventral fins are abdominal, a mesocoracoid or precoracoid arch is developed, and the anterior vertebræ are unmodified and essentially similar to the others. The orbitosphenoid is present in all typical forms. In certain forms of doubtful affinity (Iniomi) the mesocoracoid is wanting or lost in degeneration. Through the Isospondyli all the families of fishes yet to be considered are apparently descended, their ancestors being Ganoid fishes and, still farther back, the Crossopterygians.
Woodward gives this definition of the Isospondyli: "Notochord varying in persistence, the vertebral centra usually complete, but none coalesced; tail homocercal, but hæmal supports not much expanded or fused. Symplectic bone present, mandible simple, each dentary consisting only of two elements (dentary and articulo-angular), with rare rudiments of a splenoid on the inner side. Pectoral arch suspended from the cranium; precoracoid (mesocoracoid) arch present; infraclavicular plates wanting. Pelvic (ventral) fins abdominal. Scales ganoid only in the less specialized families. In the living forms air-bladder connected with the œsophagus in the adult; optic nerves decussating (without chiasma), and intestine either wanting spiral valve or with an incomplete representative of it."
=The Classification of the Bony Fishes.=—The classification of fishes has been greatly complicated by the variety of names applied to groups which are substantially but not quite identical one with another. The difference in these schemes of classification lies in the point of view. In all cases a single character must be brought to the front; such characters never stand quite alone, and to lay emphasis on another character is to make an alteration large or small in the name or in the boundaries of a class or order. Thus the Ostariophysi with the Isospondyli, Haplomi, and a few minor groups make up the great division of the Abdominales. These are fishes in which the ventral fins are abdominal, that is, inserted backward, so that the pelvis is free from the clavicle, the two sets of limbs being attached to different parts of the skeleton. Most of the abdominal fishes are also soft-rayed fishes, that is, without consecutive spines in the dorsal and anal fins, and they show a number of other archaic peculiarities. The Malacopterygians (μαλακός, soft; πτερύξ, fin) of Cuvier therefore correspond very nearly to the Abdominales. But they are not quite the same, as the spiny-rayed barracudas and mullets have abdominal ventrals, and many unquestioned thoracic or jugular fishes, as the sea-snails and brotulids, have lost, through degeneration, all of their fin-spines.
In nearly but not quite all of the Abdominal fishes the slender tube connecting the air-bladder with the œsophagus persists through life. This character defines Müller's order of Physostomi (φυσός, bladder; στόμα, mouth), as opposed to his Physoclysti (φυσός, bladder; κλεῖστός, closed), in which this tube is present in the embryo or larva only. Thus the Thoracices and Jugulares, or fishes having the ventrals thoracic or jugular, together correspond almost exactly to the Acanthopterygians, (ακανθα, spine; πτερύξ, fin), or spiny-rayed fishes of Cuvier, or to the Physoclysti of Müller. The Malacopterygians, the Abdominales, and the Physostomi are in the same way practically identical groups. As the spiny-rayed fishes have mostly ctenoid scales, and the soft-rayed fishes cycloid scales, the Physostomi correspond roughly to Agassiz's Cycloidei, and the Physoclysti to his Ctenoidei.
But in none of these cases is the correspondence perfectly exact, and in any system of classification we must choose characters for primary divisions so ancient and therefore so permanent as to leave no room for exceptions. The extraordinary difficulty of doing this, with the presence of most puzzling intergradations, has led Dr. Gill to suggest that the great body of bony fishes, soft-rayed and spiny-rayed, abdominal, thoracic, and jugular alike, be placed in a single great order which he calls Teleocephali (τελεός, perfect; κεφαλή, head). The aberrant forms with defective skull and membrane-bones he would separate as minor offshoots from this great mass with the name of separate orders. But while the divisions of Teleocephali are not strongly differentiated, their distinctive characters are real, ancient, and important, while those of the aberrant groups, called orders by Gill (as Plectognathi, Pediculati, Hemibranchii), are relatively modern and superficial, which is one reason why they are more easily defined. There seems to us no special advantage in the retention of a central order Teleocephali, from which the divergent branches are separated as distinct orders.
While our knowledge of the osteology and embryology of most of the families of fishes is very incomplete, it is evident that the relationships of the groups cannot be shown in any linear series or by any conceivable arrangement of orders and suborders. The living teleost fishes have sprung from many lines of descent, their relationships are extremely diverse, and their differences are of every possible degree of value. The ordinary schemes have magnified the value of a few common characters, at the same time neglecting other differences of equal value. No system of arrangement which throws these fishes into large groups can ever be definite or permanent.
=Relationships of Isospondyli.=—For our purposes we may divide the physostomous fishes as understood by Müller into several orders, the most primitive, the most generalized, and economically the most important being the order of Isospondyli. This order contains those bony fishes which have the anterior vertebræ unaltered (as distinguished from the Ostariophysi), the skull relatively complete, or at least not eel-like, the mesocoracoid typically developed, but atrophied in deep-sea forms and finally lost, the orbitosphenoid present. In all the species the ventral fins are abdominal and normally composed of more than six rays; the air-duct is developed. The scales are chiefly cycloid and the fins are without true spines. In many ways the order is more primitive than Nematognathi, Plectospondyli, or Apodes. It is certain that it began earlier in geological time than any of these. On the other hand, the Isospondyli are closely connected through the Berycoidei with the highly specialized fishes. The continuity of the natural series is therefore interrupted by the interposition of the side branches of Ostariophysans and eels before considering the Haplomi and the other transitional forms. The forms called Iniomi, which lack the mesocoracoid and the orbitosphenoid, have been lately transferred to the Haplomi by Boulenger. This arrangement is probably a step in advance.
Ganoid traits are present in certain families of Isospondyli. Among these are the gular plate (found in Amia and the Elopidæ), doubtless derived from the similar structure in earlier Ganoids; additional valves in the arterial bulb in the cellular air-bladder of Notopterus and Osteoglossum, the spiral intestinal valve in Chirocentridæ, and the ganoid scales of the extinct Leptolepidæ.
=The Clupeoidea.=—The Isospondyli are divisible into numerous families, which may be grouped roughly under three subdivisions, Clupeoidea, the herring-like forms; the Salmonoidea, the trout-like forms; and the Iniomi, or lantern-fishes, and their allies. The last-named group should probably be removed from the order of Isospondyli. In the Clupeoidea, the allies of the great family of the herring, the shoulder-girdle is normally developed, retaining the mesocoracoid arch on its inner edge, and through the post-temporal is articulated above with the cranium. The fishes in this group lack the adipose fin which is characteristic of most of the higher or salmon-like families.
=The Leptolepidæ.=—Most primitive of the Isospondyli is the extinct family of Leptolepidæ, closely allied to the Ganoid families of Pholidophoridæ and Oligopleuridæ. It is composed of graceful, herring-like fishes, with the bones of the head thin but covered with enamel, and the scales thin but firm and enameled on their free portion. There are no fulcra and there is no lateral line. The vertebræ are well developed, but always pierced by the notochord. The genera are Lycoptera, Leptolepis, Æthalion, and Thrissops. In Lycoptera of the Jurassic of China the vertebral centra are feebly developed, and the dorsal fin short and posterior. In Leptolepis the anal is short and placed behind the dorsal. There are many species, mostly from the Triassic and lithographic shales of Europe, one being found in the Cretaceous. Leptolepis coryphænoides and Leptolepis dubius are among the more common species. Æthalion (knorri) differs in the form of the jaws. In Thrissops the anal fin is long and opposite the dorsal. Thrissops salmonea is found in the lithographic stone; Thrissops exigua in the Cretaceous. In all these early forms there is a hard casque over the brain-cavity, as in the living types, Amia and Osteoglossum.
=The Elopidæ.=—The family of Elopidæ contains large fishes herring-like in form and structure, but having a flat membrane-bone or gular plate between the branches of the lower jaw, as in the Ganoid genus Amia. The living species are few, abounding in the tropical seas, important for their size and numbers, though not valued as food-fishes save to those who, like the Hawaiians and Japanese, eat fishes raw. These people prefer for that purpose the white-meated or soft-fleshed forms like Elops or Scarus to those which yield a better flavor when cooked.
The ten-pounder (Elops saurus), pike-like in form but with very weak teeth, is found in tropical America. Elops machnata, the jack mariddle, the awaawa of the Hawaiians, abounding in the Pacific, is scarcely if at all different.
The tarpon, called also grande écaille, silver-king, and sable (Tarpon atlanticus), is a favorite game-fish along the coasts of Florida and Carolina. It takes the hook with great spirit, and as it reaches a length of six feet or more it affords much excitement to the successful angler. The very large scales are much used in ornamental work.
A similar species of smaller size, also with the last ray of the dorsal very much produced, is Megalops cyprinoides of the East Indies. Other species occur in the South Seas.
Numerous fossil genera related to Elops are found in the Cretaceous and Tertiary rocks. Holcolepis lewesiensis (wrongly called Osmeroides) is the best-known European species. Numerous species are referred to Elopopsis. Megalops prisca and species of Elops also occur in the London Eocene.
In all these the large parietals meet along the median line of the skull. In the closely related family of Spaniodontidæ the parietals are small and do not meet. All the species of this group, united by Woodward with the Elopidæ, are extinct. These fishes preceded the Elopidæ in the Cretaceous period. Leading genera are Thrissopater and Spaniodon, the latter armed with large teeth. Spaniodon blondeli is from the Cretaceous of Mount Lebanon. Many other species are found in the European and American Cretaceous rocks, but are known from imperfect specimens only.
Sardinius, an American Cretaceous fossil herring, may stand near Spaniodon. Rhacolepis buccalis and Notelops brama are found in Brazil, beautifully preserved in concretions of calcareous mud supposed to be of Cretaceous age.
The extinct family of Pachyrhizodontidæ is perhaps allied to the Elopidæ. Numerous species of Pachyrhizodus are found in the Cretaceous of southern England and of Kansas.
=The Albulidæ.=—The Albulidæ, or lady-fishes, characterized by the blunt and rounded teeth, are found in most warm seas. Albula vulpes is a brilliantly silvery fish, little valued as food. The metamorphosis (see Fig. 112, Vol. I) which the larva undergoes is very remarkable. It is probably, however, more or less typical of the changes which take place with soft-rayed fishes generally, though more strongly marked in Albula and in certain eels than in most related forms. Fossils allied to Albula, Albula oweni, Chanoides macropomus, are found in the Eocene of Europe; Syntegmodus altus in the Cretaceous of Kansas. In Chanoides, the most primitive genus, the teeth are much fewer than in Albula. Plethodus and Thryptodus, with peculiar dental plates on the roof and floor of the mouth, probably constitute a distinct family, Thryptodontidæ. The species are found in European and American rocks, but are known from imperfect specimens only.
=The Chanidæ.=—The Chanidæ, or milkfishes, constitute another small archaic type, found in the tropical Pacific. They are large, brilliantly silvery, toothless fishes, looking like enormous dace, swift in the water, and very abundant in the Gulf of California, Polynesia, and India. The single living species is the Awa, or milkfish, Chanos chanos, largely used as food in Hawaii. Species of Prochanos and Chanos occur in the Cretaceous, Eocene, and Miocene. Allied to Chanos is the Cretaceous genus Ancylostylos (gibbus), probably the type of a distinct family, toothless and with many-rayed dorsal.
=The Hiodontidæ.=—The Hiodontidæ, or mooneyes, inhabit the rivers of the central portion of the United States and Canada. They are shad-like fishes with brilliantly silvery scales and very strong sharp teeth, those on the tongue especially long. They are very handsome fishes and take the hook with spirit, but the flesh is rather tasteless and full of small bones, much like that of the milkfish. The commonest species is Hiodon tergisus. No fossil Hiodontidæ are known.
=The Pterothrissidæ.=—The Pterothrissidæ are sea-fishes like Albula, but more slender and with a long dorsal fin. They live in deep or cold waters along the coasts of Japan, where they are known as gisu. The single species is Pterothrissus gissu. The fossil genus Istieus, from the Upper Cretaceous, probably belongs near the Pterothrissidæ. Istieus grandis is the best-known species. Another ancient family, now represented by a single species, is that of the Chirocentridæ, of which the living type is Chirocentrus dorab, a long, slender, much compressed herring-like fish, with a saw-edge on the belly, found in the East Indies, in which region Chirocentrus polyodon occurs as a fossil. Numerous fossil genera related to Chirocentrus are enumerated by Woodward, most of them to be referred to the related family of Ichthyodectidæ (Saurodontidæ). Of these, Portheus, Ichthyodectes, Saurocephalus (Saurodon), and Gillicus are represented by numerous species, some of them fishes of immense size and great voracity. Portheus molossus, found in the Cretaceous of Nebraska, is remarkable for its very strong teeth. Species of other genera are represented by numerous species in the Cretaceous of both the Rocky Mountain region and of Europe.
=The Ctenothrissidæ.=—A related family, Ctenothrissidæ, is represented solely by extinct Cretaceous species. In this group the body is robust with large scales, ctenoid in Ctenothrissa, cycloid in Aulolepis. The fins are large, the belly not serrated, and the teeth feeble. Ctenothrissa vexillifera is from Mount Lebanon. Other species occur in the European chalk. In the small family of Phractolæmidæ the interopercle, according to Boulenger, is enormously developed.
=The Notopteridæ.=—The Notopteridæ is another small family in the rivers of Africa and the East Indies. The body ends in a long and tapering fin, and, as usual in fishes which swim by body undulations, the ventral fins are lost. The belly is doubly serrate. The air-bladder is highly complex in structure, being divided into several compartments and terminating in two horns anteriorly and posteriorly, the anterior horns being in direct communication with the auditory organ. A fossil Notopterus, N. primævus, is found in the same region.
=The Clupeidæ.=—The great herring family, or Clupeidæ, comprises fishes with oblong or herring-shaped body, cycloid scales, and feeble dentition. From related families it is separated by the absence of lateral line and the division of the maxillary into three pieces. In most of the genera the belly ends in a serrated edge, though in the true herring this is not very evident, and in some the belly has a blunt edge. Some of the species live in rivers, some ascend from the sea for the purpose of spawning. The majority are confined to the ocean. Among all the genera, the one most abundant in individuals is that of Clupea, the herring. Throughout the North Atlantic are immense schools of Clupea harengus. In the North Pacific on both shores another herring, Clupea pallasi, is equally abundant, and with the same market it would be equally valuable. As salted, dried, or smoked fish the herring is found throughout the civilized world, and its spawning and feeding-grounds have determined the location of cities.
The genus Clupea, of northern distribution, has the vertebræ in increased number (56), and there are weak teeth on the vomer. Several other genera are very closely related, but ranging farther south they have, with other characters, fewer (46 to 50) vertebræ. The alewife, or branch-herring (Pomolobus pseudoharengus), ascends the rivers to spawn and has become landlocked in the lakes of New York. The skipjack of the Gulf of Mexico, Pomolobus chrysochloris, becomes very fat in the sea. The species becomes landlocked in the Ohio River, where it thrives as to numbers, but remains lean and almost useless as food. The glut-herring, Pomolobus æstivalis, and the sprat, Pomolobus sprattus, of Europe are related forms.
Very near also to the herring is the shad (Alosa sapidissima) of the eastern coasts of America, and its inferior relatives, the shad of the Gulf of Mexico (Alosa alabamæ), the Ohio River shad (Alosa ohiensis), very lately discovered, the Allice shad (Alosa alosa) of Europe, and the Thwaite shad (Alosa finta). In the genus Alosa the cheek region is very deep, giving the head a form different from that seen in the herring.
The American shad is the best food-fish in the family, peculiarly delicate in flavor when broiled, but, to a greater degree than occurs in any other good food-fish, its flesh is crowded with small bones. The shad has been successfully introduced into the waters of California, where it abounds from Puget Sound to Point Concepcion, ascending the rivers to spawn in May as in its native region, the Atlantic coast.
The genus Sardinella includes species of rich flesh and feeble skeleton, excellent when broiled, when they may be eaten bones and all. This condition favors their preservation in oil as "sardines." All the species are alike excellent for this purpose. The sardine of Europe is the Sardinella pilchardus, known in England as the pilchard. The "Sardina de España" of Cuba is Sardinella pseudohispanica, the sardine of California, Sardinella cærulea. Sardinella sagax abounds in Chile, and Sardinella melanosticta is the valued sardine of Japan.
In the tropical Pacific occur other valued species, largely belonging to the genus Kowala. The genus Harengula contains small species with very large, firm scales which do not fall when touched, as is generally the case with the sardines. Most common of these is Harengula sardina of the West Indies. Similar species occur in southern Europe and in Japan.
In Opisthonema, the thread-herring, the last dorsal ray is much produced, as in the gizzard-shad and the tarpon. The two species known are abundant, but of little commercial importance. Of greater value are the menhaden, or the moss-bunker, Brevoortia tyrannus, inhabiting the sandy coasts from New England southward. It is a coarse and bony fish, rarely eaten when adult, although the young in oil makes acceptable sardines. It is used chiefly for oil, the annual yield exceeding in value that of whale-oil. The refuse is used as manure, a purpose for which the fishes are often taken without preparation, being carried directly to the cornfields. From its abundance this species of inferior flesh exceeds in commercial value almost all other American fishes excepting the cod, the herring, and the quinnat salmon.
One of the most complete of fish biographies is that of Dr. G. Brown Goode on the "Natural and Economic History of Menhaden."
Numerous other herring-like forms, usually with compressed bodies, dry and bony flesh, and serrated bellies, abound in the tropics and are largely salted and dried by the Chinese. Among these are Ilisha elongata of the Chinese coast. Related forms occur in Mexico and Brazil.
The round herrings, small herrings which have no serrations on the belly, are referred by Dr. Gill to the family of Dussumieriidæ. These are mostly small tropical fishes used as food or bait. One of these, the Kobini-Iwashi of Japan (Stolephorus japonicus), with a very bright silver band on the side, has considerable commercial importance. Very small herrings of this type in the West Indies constitute the genus Jenkinsia, named for Dr. Oliver P. Jenkins, the first to study seriously the fishes of Hawaii. Other species constitute the widely distributed genera Etrumeus and Dussumieria. Etrumeus sardina is the round herring of the Virginia coast. Etrumeus micropus is the Etrumei-Iwashi of Japan and Hawaii.
Fossil herring are plentiful and exist in considerable variety, even among the Clupeidæ as at present restricted. Histiothrissa of the Cretaceous seems to be allied to Dussumieria and Stolephorus. Another genus, from the Cretaceous of Palestine, Pseudoberyx (syriacus, etc.), having pectinated scales, should perhaps constitute a distinct subfamily, but the general structure is like that of the herring. More evidently herring-like is Scombroclupea (macrophthalma). The genus Diplomystus, with enlarged scales along the back, is abundantly represented in the Eocene shales of Green River, Wyoming. Species of similar appearance, usually but wrongly referred to the same genus, occur on the coasts of Peru, Chile, and New South Wales. A specimen of Diplomystus humilis from Green River is here figured. Numerous herring, referred to Clupea, but belonging rather to Pomolobus, or other non-Arctic genera, have been described from the Eocene and later rocks.
Several American fossil herring-like fishes, of the genus Leptosomus, as Leptosomus percrassus, are found in the Cretaceous of South Dakota.
Fossil species doubtfully referred to Dorosoma, but perhaps allied rather to the thread-herring (Opisthonema), being herrings with a prolonged dorsal ray, are recorded from the early Tertiary of Europe. Among these is Opisthonema doljeanum from Austria.
=The Dorosomatidæ.=—The gizzard-shad, Dorosomatidæ, are closely related to the Clupeidæ, differing in the small contracted toothless mouth and reduced maxillary. The species are deep-bodied, shad-like fishes of the rivers and estuaries of eastern America and eastern Asia. They feed on mud, and the stomach is thickened and muscular like that of a fowl. As the stomach has the size and form of a hickory-nut, the common American species is often called hickory-shad. The gizzard-shad are all very poor food-fish, bony and little valued, the flesh full of small bones. The belly is always serrated. In three of the four genera of Dorosomatidæ the last dorsal ray is much produced and whip-like. The long and slender gill-rakers serve as strainers for the mud in which these fishes find their vegetable and animal food. Dorosoma cepedianum, the common hickory-shad or gizzard-shad, is found in brackish river-mouths and ponds from Long Island to Texas, and throughout the Mississippi Valley in all the large rivers. Through the canals it has entered Lake Michigan. The Konoshiro, Clupanodon thrissa, is equally common in China and Japan.
=The Engraulididæ.=—The anchovies (Engraulididæ) are dwarf herrings with the snout projecting beyond the very wide mouth. They are small in size and weak in muscle, found in all warm seas, and making a large part of the food of the larger fish. The genus Engraulis includes the anchovy of Europe, Engraulis encrasicholus, with similar species in California, Chile, Japan, and Australia. In this genus the vertebræ are numerous, the bones feeble, and the flesh tender and oily. The species of Engraulis are preserved in oil, often with spices, or are made into fish-paste, which is valued as a relish. The genus Anchovia replaces Engraulis in the tropics. The vertebræ are fewer, the bones firm and stiff, and the flesh generally dry. Except as food for larger fish, these have little value, although existing in immense schools. Most of the species have a bright silvery band along the side. The most familiar of the very numerous species is the silver anchovy, Anchovia browni, which abounds in sandy bays from Cape Cod to Brazil. Several other genera occur farther southward, as well as in Asia, but Engraulis only is found in Europe. Fossil anchovies called Engraulis are recorded from the Tertiary of Europe.
=Gonorhynchidæ.=—To the Isospondyli belongs the small primitive family of Gonorhynchidæ, elongate fishes with small mouth, feeble teeth, no air-bladder, small scales of peculiar structure covering the head, weak dentition, the dorsal fin small, and posterior without spines. The mesocoracoid is present as in ordinary Isospondyli. Gonorhynchus abbreviatus occurs in Japan, and Gonorhynchus gonorhynchus is found in Australia and about the Cape of Good Hope. Numerous fossil species occur. Charitosomus lineolatus and other species are found in the Cretaceous of Mount Lebanon and elsewhere. Species without teeth from the Oligocene of Europe and America are referred to the genus Notogoneus. Notogoneus osculus occurs in the Eocene fresh-water deposits at Green River, Wyoming. It bears a very strong resemblance in form to an ordinary sucker (Catostomus), for which reason it was once described by the name of Protocatostomus. The living Gonorhynchidæ are all strictly marine.
In the small family of Cromeriidæ the head and body are naked.
=The Osteoglossidæ.=—Still less closely related to the herring is the family of Osteoglossidæ, huge pike-like fishes of the tropical rivers, armed with hard bony scales formed of pieces like mosaic. The largest of all fresh-water fishes is Arapaima gigas of the Amazon region, which reaches a length of fifteen feet and a weight of 400 pounds. It has naturally considerable commercial importance, as have species of Osteoglossum, coarse river-fishes which occur in Brazil, Egypt, and the East Indies. Heterotis nilotica is a large fish of the Nile. In some or all of these the air-bladder is cellular or lung-like, like that of a Ganoid.
Allied to the Osteoglossidæ is Phareodus (Dapedoglossus), a group of large shad-like fossil fishes, with large scales of peculiar mosaic texture and with a bony casque on the head, found in fresh-water deposits of the Green River Eocene. In the perfect specimens of Phareodus (or Dapedoglossus) testis the first ray of the pectoral is much enlarged and serrated on its inner edge, a character which may separate these fishes as a family from the true Osteoglossidæ. It does not, however, appear in Cope's figures, none of his specimens having the pectorals perfect. In these fishes the teeth are very strong and sharp, the scales are very large and thin, looking like the scales of a parrot-fish, the long dorsal is opposite to the anal and similar to it, and the caudal is truncate. The end of the vertebral column is turned upward.
Other species are Phareodus acutus, known from the jaws; P. encaustus is known from a mass of thick scales with reticulate or mosaic-like surface, much as in Osteoglossum, and P. æquipennis from a small example, perhaps immature. Phareodus testis is frequently found well preserved in the shales at Fossil Station, to the northwestward of Green River. Whether all these species possess the peculiar structure of the scales, and whether all belong to one genus, is uncertain.
In Eocene shales of England occurs Brychætus muelleri, a species closely related to Phareodus, but the scales smaller and without the characteristic reticulate or mosaic structure seen in Phareodus encaustus.
=The Pantodontidæ.=—The bony casque of Osteoglossum is found again in the Pantodontidæ, consisting of one species, Pantodon buchholzi, a small fish of the brooks of West Africa. As in the Osteoglossidæ and in the Siluridæ, the subopercle is wanting in Pantodon.
The Alepocephalidæ are deep-sea herring-like fishes very soft in texture and black in color, taken in the oceanic abysses. Some species may be found in almost all seas below the depth of half a mile. Alepocephalus rostratus of the Mediterranean has been long known, but most of the other genera, Talismania, Mitchillina, Conocara, etc., are of very recent discovery, having been brought to the surface by the deep-sea dredging of the Challenger, the Albatross, the Blake, the Travailleur, the Talisman, the Investigator, the Hirondelle, and the Violante.
IV. SALMONIDÆ
=THE Salmon Family.=—The series or suborder Salmonoidea, or allies of the salmon and trout, are characterized as a whole by the presence of the adipose fin, a structure also retained in Characins and catfishes, which have no evident affinity with the trout, and in the lantern-fishes, lizard-fishes, and trout-perches, in which the affinity is very remote. Probably these groups all have a common descent from some primitive fish having an adipose fin, or at least a fleshy fold on the back.
Of all the families of fishes, the one most interesting from almost every point of view is that of the Salmonidæ, the salmon family. As now restricted, it is not one of the largest families, as it comprises less than a hundred species; but in beauty, activity, gaminess, quality as food, and even in size of individuals, different members of the group stand easily with the first among fishes. The following are the chief external characteristics which are common to the members of the family:
Body oblong or moderately elongate, covered with cycloid, in scales of varying size. Head naked. Mouth terminal or somewhat inferior, varying considerably among the different species, those having the mouth largest usually having also the strongest teeth. Maxillary provided with a supplemental bone, and forming the lateral margin of the upper jaw. Pseudobranchiæ present. Gill-rakers varying with the species. Opercula complete. No barbels. Dorsal fin of moderate length, placed near the middle of the length of the body. Adipose fin well developed. Caudal fin forked. Anal fin moderate or rather long. Ventral fins nearly median in position. Pectoral fins inserted low. Lateral line present. Outline of belly rounded. Vertebræ in large number, usually about sixty.
The stomach in all the Salmonidæ is siphonal, and at the pylorus are many (15 to 200) comparatively large pyloric cœca. The air-bladder is large. The eggs are usually much larger than in fishes generally, and the ovaries are without special duct, the ova falling into the cavity of the abdomen before exclusion. The large size of the eggs, their lack of adhesiveness, and the readiness with which they may be impregnated, render the Salmonidæ peculiarly adapted for artificial culture.
The Salmonidæ are peculiar to the north temperate and Arctic regions, and within this range they are almost equally abundant wherever suitable waters occur. Some of the species, especially the larger ones, are marine and anadromous, living and growing in the sea, and ascending fresh waters to spawn. Still others live in running brooks, entering lakes or the sea when occasion serves, but not habitually doing so. Still others are lake fishes, approaching the shore or entering brooks in the spawning season, at other times retiring to waters of considerable depth. Some of them are active, voracious, and gamy, while others are comparatively defenseless and will not take the hook. They are divisible into ten easily recognized genera: Coregonus, Argyrosomus, Brachymystax, Stenodus, Oncorhynchus, Salmo, Hucho, Cristivomer, Salvelinus, and Plecoglossus.
Fragments of fossil trout, very imperfectly known, are recorded chiefly from Pleistocene deposits of Idaho, under the name of Rhabdofario lacustris. We have also received from Dr. John C. Merriam, from ferruginous sands of the same region, several fragments of jaws of salmon, in the hook-nosed condition, with enlarged teeth, showing that the present salmon-runs have been in operation for many thousands of years. Most other fragments hitherto referred to Salmonidæ belong to some other kind of fish.
=Coregonus, the Whitefish.=—The genus Coregonus, which includes the various species known in America as lake whitefish, is distinguishable in general by the small size of its mouth, the weakness of its teeth, and the large size of its scales. The teeth, especially, are either reduced to slight asperities, or else are altogether wanting. The species reach a length of one to three feet. With scarcely an exception they inhabit clear lakes, and rarely enter streams except to spawn. In far northern regions they often descend to the sea; but in the latitude of the United States this is never possible for them, as they are unable to endure warm or impure water. They seldom take the hook, and rarely feed on other fishes. Numerous local varieties characterize the lakes of Scandinavia, Scotland, and Arctic Asia and America. Largest and most desirable of all these as a food-fish is the common whitefish of the Great Lakes (Coregonus clupeiformis), with its allies or variants in the Mackenzie and Yukon.
The species of Coregonus differ from each other in the form and size of the mouth, in the form of the body, and in the development of the gill-rakers.
Coregonus oxyrhynchus—the Schnäbel of Holland, Germany, and Scandinavia—has the mouth very small, the sharp snout projecting far beyond it. No species similar to this is found in America.
The Rocky Mountain whitefish (Coregonus williamsoni) has also a small mouth and projecting snout, but the latter is blunter and much shorter than in C. oxyrhynchus. This is a small species abounding everywhere in the clear lakes and streams of the Rocky Mountains and the Sierra Nevada, from Colorado to Vancouver Island. It is a handsome fish and excellent as food.
Closely allied to Coregonus williamsoni is the pilot-fish, shad-waiter, roundfish, or Menomonee whitefish (Coregonus quadrilateralis). This species is found in the Great Lakes, the Adirondack region, the lakes of New Hampshire, and thence northwestward to the Yukon, abounding in cold deep waters, its range apparently nowhere coinciding with that of Coregonus williamsoni.
The common whitefish (Coregonus clupeiformis) is the largest in size of the species of Coregonus, and is unquestionably the finest as an article of food. It varies considerably in appearance with age and condition, but in general it is proportionately much deeper than any of the other small-mouthed Coregoni. The adult fishes develop a considerable fleshy hump at the shoulders, which causes the head, which is very small, to appear disproportionately so. The whitefish spawns in November and December, on rocky shoals in the Great Lakes. Its food was ascertained by Dr. P. R. Hoy to consist chiefly of deep-water crustaceans, with a few mollusks, and larvæ of water insects. "The whitefish," writes Mr. James W. Milner, "has been known since the time of the earliest explorers as preeminently a fine-flavored fish. In fact there are few table-fishes its equal. To be appreciated in its fullest excellence it should be taken fresh from the lake and broiled. Father Marquette, Charlevoix, Sir John Richardson—explorers who for months at a time had to depend upon the whitefish for their staple article of food— bore testimony to the fact that they never lost their relish for it, and deemed it a special excellence that the appetite never became cloyed with it." The range of the whitefish extends from the lakes of New York and New England northward to the Arctic Circle. The "Otsego bass" of Otsego Lake in New York, celebrated by De Witt Clinton, is a local form of the ordinary whitefish.
Allied to the American whitefish, but smaller in size, is the Lavaret, Weissfisch, Adelfisch, or Weissfelchen (Coregonus lavaretus), of the mountain lakes of Switzerland, Germany, and Sweden. Coregonus kennicotti, the muksun, and Coregonus nelsoni, the humpback whitefish, are found in northern Alaska and in the Yukon. Several other related species occur in northern Europe and Siberia.
Another American species is the Sault whitefish, Lake Whiting or Musquaw River whitefish (Coregonus labradoricus). Its teeth are stronger, especially on the tongue, than in any of our other species, and its body is slenderer than that of the whitefish. It is found in the upper Great Lakes, in the Adirondack region, in Lake Winnipeseogee, and in the lakes of Maine and New Brunswick. It is said to rise to the fly in the Canadian lakes. This species runs up the St. Mary's River, from Lake Huron to Lake Superior, in July and August. Great numbers are snared or speared by the Indians at this season at the Sault Ste. Marie.
In the breeding season the scales are sometimes thickened or covered with small warts, as in the male Cyprinidæ.
=Argyrosomus, the Lake Herring.=—In the genus Argyrosomus the mouth is larger, the premaxillary not set vertical, but extending forward on its lower edge, and the body is more elongate and more evenly elliptical. The species are more active and predaceous than those of Coregonus and are, on the whole, inferior as food.
The smallest and handsomest of the American whitefish is the cisco of Lake Michigan (Argyrosomus hoyi). It is a slender fish, rarely exceeding ten inches in length, and its scales have the brilliant silvery luster of the mooneye and the ladyfish.
The lake herring, or cisco (Argyrosomus artedi), is, next to the whitefish, the most important of the American species. It is more elongate than the others, and has a comparatively large mouth, with projecting under-jaw. It is correspondingly more voracious, and often takes the hook. During the spawning season of the whitefish the lake herring feeds on the ova of the latter, thereby doing a great amount of mischief. As food this species is fair, but much inferior to the whitefish. Its geographical distribution is essentially the same, but to a greater degree it frequents shoal waters. In the small lakes around Lake Michigan, in Indiana and Wisconsin (Tippecanoe, Geneva, Oconomowoc, etc.), the cisco has long been established; and in these waters its habits have undergone some change, as has also its external appearance. It has been recorded as a distinct species, Argyrosomus sisco, and its excellence as a game-fish has been long appreciated by the angler. These lake ciscoes remain for most of the year in the depths of the lake, coming to the surface only in search of certain insects, and to shallow water only in the spawning season. This periodical disappearance of the cisco has led to much foolish discussion as to the probability of their returning by an underground passage to Lake Michigan during the periods of their absence. One author, confounding "cisco" with "siscowet," has assumed that this underground passage leads to Lake Superior, and that the cisco is identical with the fat lake trout which bears the latter name. The name "lake herring" alludes to the superficial resemblance which this species possesses to the marine herring, a fish of quite a different family.
Closely allied to the lake herring is the bluefin of Lake Michigan and of certain lakes in New York (Argyrosomus nigripinnis), a fine large species inhabiting deep waters, and recognizable by the blue-black color of its lower fins. In the lakes of central New York are found two other species, the so-called lake smelt (Argyrosomus osmeriformis) and the long-jaw (Argyrosomus prognathus). Argyrosomus lucidus is abundant in Great Bear Lake. In Alaska and Siberia are still other species of the cisco type (Argyrosomus laurettæ, A. pusillus, A. alascanus); and in Europe very similar species are the Scotch vendace (Argyrosomus vandesius) and the Scandinavian Lok-Sild (lake herring), as well as others less perfectly known.
The Tullibee, or "mongrel whitefish" (Argyrosomus tullibee), has a deep body, like the shad, with the large mouth of the ciscoes. It is found in the Great Lake region and northward, and very little is known of its habits. A similar species (Argyrosomus cyprinoides) is recorded from Siberia—a region which is peculiarly suited for the growth of the Coregoni, but in which the species have never received much study.
=Brachymystax and Stenodus, the Inconnus.=—Another little-known form, intermediate between the whitefish and the salmon, is Brachymystax lenock, a large fish of the mountain streams of Siberia. Only the skins brought home by Pallas a century ago are yet known. According to Pallas, it sometimes reaches a weight of eighty pounds.
Still another genus, intermediate between the whitefish and the salmon, is Stenodus, distinguished by its elongate body, feeble teeth, and projecting lower jaw. The Inconnu, or Mackenzie River salmon, known on the Yukon as "charr" (Stenodus mackenziei), belongs to this genus. It reaches a weight of twenty pounds or more, and in the far north is a food-fish of good quality. It runs in the Yukon as far as White Horse Rapids. Not much is recorded of its habits, and few specimens exist in museums. A species of Stenodus called Stenodus leucichthys inhabits the Volga, Obi, Lena, and other northern rivers; but as yet little is definitely known of the species.
=Oncorhynchus, the Quinnat Salmon.=—The genus Oncorhynchus contains the salmon of the Pacific. They are in fact, as well as in name, the king salmon. The genus is closely related to Salmo, with which it agrees in general as to the structure of its vomer, and from which it differs in the increased number of anal rays, branchiostegals, pyloric cœca, and gill-rakers. The character most convenient for distinguishing Oncorhynchus, young or old, from all the species of Salmo, is the number of developed rays in the anal fin. These in Oncorhynchus are thirteen to twenty, in Salmo nine to twelve.
The species of Oncorhynchus have long been known as anadromous salmon, confined to the North Pacific. The species were first made known nearly one hundred and fifty years ago by that most exact of early observers, Steller, who, almost simultaneously with Krascheninnikov, another early investigator, described and distinguished them with perfect accuracy under their Russian vernacular names. These Russian names were, in 1792, adopted by Walbaum as specific names in giving to these animals a scientific nomenclature. Five species of Oncorhynchus are well known on both shores of the North Pacific, besides one other in Japan. These have been greatly misunderstood by early observers on account of the extraordinary changes due to differences in surroundings, in sex, and in age, and in conditions connected with the process of reproduction.
There are five species of salmon (Oncorhynchus) in the waters of the North Pacific, all found on both sides, besides one other which is known only from the waters of Japan. These species may be called: (1) the quinnat, or king-salmon, (2) the blue-back salmon, or redfish, (3) the silver salmon, (4) the dog-salmon, (5) the humpback salmon, and (6) the masu; or (1) Oncorhynchus tschawytscha, (2) Oncorhynchus nerka, (3) Oncorhynchus milktschitsch, (4) Oncorhynchus keta, (5) Oncorhynchus gorbuscha, (6) Oncorhynchus masou. All these species save the last are now known to occur in the waters of Kamchatka, as well as in those of Alaska and Oregon. These species, in all their varied conditions, may usually be distinguished by the characters given below. Other differences of form, color, and appearance are absolutely valueless for distinction, unless specimens of the same age, sex, and condition are compared.
The quinnat salmon (Oncorhynchus tschawytscha),[7] called quinnat, tyee, chinook, or king-salmon, has an average weight of 22 pounds, but individuals weighing 70 to 100 pounds are occasionally taken. It has about 16 anal rays, 15 to 19 branchiostegals, 23 (9 + 14) gill-rakers on the anterior gill-arch, and 140 to 185 pyloric cœca. The scales are comparatively large, there being from 130 to 155 in a longitudinal series. In the spring the body is silvery, the back, dorsal fin, and caudal fin having more or less of round black spots, and the sides of the head having a peculiar tin-colored metallic luster. In the fall the color is often black or dirty red, and the species can then be distinguished from the dog-salmon by its larger size and by its technical characters. The flesh is rich and salmon-red, becoming suddenly pale as the spawning season draws near.
Footnote 7:
For valuable accounts of the habits of this species the reader is referred to papers by the late Cloudsley Rutter, ichthyologist of the Albatross, in the publications of the United States Fish Commission, the Popular Science Monthly, and the Overland Monthly.
The blue-back salmon (Oncorhynchus nerka),[8] also called red salmon, sukkegh, or sockeye, usually weighs from 5 to 8 pounds. It has about 14 developed anal rays, 14 branchiostegals, and 75 to 95 pyloric cœca. The gill-rakers are more numerous than in any other salmon, the number being usually about 39 (16 + 23). The scales are larger, there being 130 to 140 in the lateral line. In the spring the form is plumply rounded, and the color is a clear bright blue above, silvery below, and everywhere immaculate. Young fishes often show a few round black spots, which disappear when they enter the sea. Fall specimens in the lakes are bright crimson in color, the head clear olive-green, and they become in a high degree hook-nosed and slab-sided, and bear little resemblance to the spring run. Young spawning male grilse follow the changes which take place in the adult, although often not more than half a pound in weight. These little fishes often appear in mountain lakes, but whether they are landlocked or have come up from the sea is still unsettled. These dwarf forms, called kokos by the Indians and benimasu in Japan, form the subspecies Oncorhynchus nerka kennerlyi. The flesh in this species is firmer than that of any other and very red, of good flavor, though drier and less rich than the king-salmon.
Footnote 8:
For valuable records of the natural history of this species the reader is referred to various papers by Dr. Barton Warren Evermann in the Bulletins of the United States Fish Commission and elsewhere.
The silver salmon, or coho (Oncorhynchus milktschitsch, or kisutch), reaches a weight of 5 to 8 pounds. It has 13 developed rays in the anal, 13 branchiostegals, 23 (10 + 13) gill-rakers, and 45 to 80 pyloric cœca. There are about 127 scales in the lateral line. The scales are thin and all except those of the lateral line readily fall off. This feature distinguishes the species readily from the red salmon. In color it is silvery in spring, greenish above, and with a few faint black spots on the upper parts only. In the fall the males are mostly of a dirty red. The flesh in this species is of excellent flavor, but pale in color, and hence less valued than that of the quinnat and the red salmon.
The dog-salmon, calico salmon, or chum, called saké in Japan (Oncorhynchus keta), reaches an average weight of about 7 to 10 pounds. It has about 14 anal rays, 14 branchiostegals, 24 (9 + 15) gill-rakers, and 140 to 185 pyloric cœca. There are about 150 scales in the lateral line. In spring it is dirty silvery, immaculate, or sprinkled with small black specks, the fins dusky, the sides with faint traces of gridiron-like bars. In the fall the male is brick-red or blackish, and its jaws are greatly distorted. The pale flesh is well flavored when fresh, but pale and mushy in texture and muddy in taste when canned. It is said to take salt well, and great numbers of salt dog-salmon are consumed in Japan.
The humpback salmon, or pink salmon (Oncorhynchus gorbuscha), is the smallest of the American species, weighing from 3 to 5 pounds. It has usually 15 anal rays, 12 branchiostegals, 28 (13 + 15) gill-rakers, and about 180 pyloric cœca. Its scales are much smaller than in any other salmon, there being 180 to 240 in the lateral line. In color it is bluish above, silvery below, the posterior and upper parts with many round black spots, the caudal fin always having a few large black spots oblong in form. The males in fall are dirty red, and are more extravagantly distorted than in any other of the Salmonidæ. The flesh is softer than in the other species; it is pale in color, and, while of fair flavor when fresh, is distinctly inferior when canned.
The masu, or yezomasu (Oncorhynchus masou), is very similar to the humpback, the scales a little larger, the caudal without black spots, the back usually immaculate. It is one of the smaller salmon, and is fairly abundant in the streams of Hokkaido, the island formerly known as Yezo.
Of these species the blue-back or red salmon predominates in Frazer River and in most of the small rivers of Alaska, including all those which flow from lakes. The greatest salmon rivers of the world are the Nushegak and Karluk in Alaska, with the Columbia River, Frazer River, and Sacramento River farther south. The red and the silver salmon predominate in Puget Sound, the quinnat in the Columbia and the Sacramento, and the silver salmon in most of the smaller streams along the coast. All the species occur, however, from the Columbia northward; but the blue-back is not found in the Sacramento. Only the quinnat and the dog-salmon have been noticed south of San Francisco. In Japan keta is by far the most abundant species of salmon. It is known as saké, and largely salted and sold in the markets. Nerka is known in Japan only as landlocked in Lake Akan in northern Hokkaido. Milktschitsch is generally common, and with masou is known as masu, or small salmon, as distinguished from the large salmon, or saké. Tschawytscha and gorbuscha are unknown in Japan. Masou has not been found elsewhere.
The quinnat and blue-back salmon, the "noble salmon," habitually "run" in the spring, the others in the fall. The usual order of running in the rivers is as follows: tschawytscha, nerka, milktschitsch, gorbuscha, keta. Those which run first go farthest. In the Yukon the quinnat runs as far as Caribou Crossing and Lake Bennett, 2250 miles. The red salmon runs to "Forty-Mile," which is nearly 1800 miles. Both ascend to the head of the Columbia, Fraser, Nass, Skeena, Stikeen, and Taku rivers. The quinnat runs practically only in the streams of large size, fed with melting snows; the red salmon only in streams which pass through lakes. It spawns only in small streams at the head of a lake. The other species spawn in almost any fresh water and only close to the sea.
The economic value of the spring-running salmon is far greater than that of the other species, because they can be captured in numbers when at their best, while the others are usually taken only after deterioration.
The habits of the salmon in the ocean are not easily studied. Quinnat and silver salmon of all sizes are taken with the seine at almost any season in Puget Sound and among the islands of Alaska. This would indicate that these species do not go far from the shore. The silver salmon certainly does not. The quinnat pursues the schools of herring. It takes the hook freely in Monterey Bay, both near the shore and at a distance of six to eight miles out. We have reason to believe that these two species do not necessarily seek great depths, but probably remain not very far from the mouth of the rivers in which they were spawned. The blue-back or red salmon certainly seeks deeper water, as it is seldom or never taken with the seine along shore, and it is known to enter the Strait of Fuca in July, just before the running season, therefore coming in from the open sea. The great majority of the quinnat salmon, and probably all the blue-back salmon, enter the rivers in the spring. The run of the quinnat begins generally at the last of March; it lasts, with various modifications and interruptions, until the actual spawning season in November, the greatest run being in early June in Alaska, in July in the Columbia. The run begins earliest in the northernmost rivers, and in the longest streams, the time of running and the proportionate amount in each of the subordinate runs varying with each different river. In general the runs are slack in the summer and increase with the first high water of autumn. By the last of August only straggling blue-backs can be found in the lower course of any stream; but both in the Columbia and in the Sacramento the quinnat runs in considerable numbers at least till October. In the Sacramento the run is greatest in the fall, and more run in the summer than in spring. In the Sacramento and the smaller rivers southward there is a winter run, beginning in December. The spring quinnat salmon ascends only those rivers which are fed by the melting snows from the mountains and which have sufficient volume to send their waters well out to sea. Those salmon which run in the spring are chiefly adults (supposed to be at least three years old). Their milt and spawn are no more developed than at the same time in others of the same species which have not yet entered the rivers. It would appear that the contact with cold fresh water, when in the ocean, in some way causes them to run towards it, and to run before there is any special influence to that end exerted by the development of the organs of generation. High water on any of these rivers in the spring is always followed by an increased run of salmon. The salmon-canners think—and this is probably true—that salmon which would not have run till later are brought up by the contact with the cold water. The cause of this effect of cold fresh water is not understood. We may call it an instinct of the salmon, which is another way of expressing our ignorance. In general it seems to be true that in those rivers and during those years when the spring run is greatest the fall run is least to be depended on.
The blue-back salmon runs chiefly in July and early August, beginning in late June in Chilcoot River, where some were found actually spawning July 15; beginning after the middle of July in Frazer River.
As the season advances, smaller and younger salmon of these species (quinnat and blue-back) enter the rivers to spawn, and in the fall these young specimens are very numerous. We have thus far failed to notice any gradations in size or appearance of these young fish by which their ages could be ascertained. It is, however, probable that some of both sexes reproduce at the age of one year. In Frazer River, in the fall, quinnat male grilse of every size, from eight inches upwards, were running, the milt fully developed, but usually not showing the hooked jaws and dark colors of the older males. Females less than eighteen inches in length were not seen. All of either sex, large and small, then in the river had the ovaries or milt developed. Little blue-backs of every size, down to six inches, are also found in the upper Columbia in the fall, with their organs of generation fully developed. Nineteen-twentieths of these young fish are males, and some of them have the hooked jaws and red color of the old males. Apparently all these young fishes, like the old ones, die after spawning.
The average weight of the adult quinnat in the Columbia, in the spring, is twenty-two pounds; in the Sacramento, about sixteen. Individuals weighing from forty to sixty pounds are frequently found in both rivers, and some as high as eighty or even one hundred pounds are recorded, especially in Alaska, where the species tends to run larger. It is questionable whether these large fishes are those which, of the same age, have grown more rapidly; those which are older, but have for some reason failed to spawn; or those which have survived one or more spawning seasons. All these origins may be possible in individual cases. There is, however, no positive evidence that any salmon of the Pacific survives the spawning season.
Those fish which enter the rivers in the spring continue their ascent till death or the spawning season overtakes them. Doubtless not one of them ever returns to the ocean, and a large proportion fail to spawn. They are known to ascend the Sacramento to its extreme head-waters, about four hundred miles. In the Columbia they ascend as far as the Bitter Root and Sawtooth mountains of Idaho, and their extreme limit is not known. This is a distance of nearly a thousand miles. In the Yukon a few ascend to Caribou Crossing and Lake Bennett, 2250 miles. At these great distances, when the fish have reached the spawning grounds, besides the usual changes of the breeding season their bodies are covered with bruises, on which patches of white fungus (Saprolegnia) develop. The fins become mutilated, their eyes are often injured or destroyed, parasitic worms gather in their gills, they become extremely emaciated, their flesh becomes white from the loss of oil; and as soon as the spawning act is accomplished, and sometimes before, all of them die. The ascent of the Cascades and the Dalles of the Columbia causes the injury or death of a great many salmon.
When the salmon enter the river they refuse to take bait, and their stomachs are always found empty and contracted. In the rivers they do not feed; and when they reach the spawning grounds their stomachs, pyloric cœca and all, are said to be no larger than one's finger. They will sometimes take the fly, or a hook baited with salmon-roe, in the clear waters of the upper tributaries, but this is apparently solely out of annoyance, snapping at the meddling line. Only the quinnat and blue-back (there called redfish) have been found at any great distance from the sea, and these (as adult fishes) only in late summer and fall.
The spawning season is probably about the same for all the species. It varies for each of the different rivers, and for different parts of the same river. It doubtless extends from July to December, and takes place usually as soon as the temperature of the water falls to 54°. The manner of spawning is probably similar for all the species. In the quinnat the fishes pair off; the male, with tail and snout, excavates a broad, shallow "nest" in the gravelly bed of the stream, in rapid water, at a depth of one to four feet and the female deposits her eggs in it. They then float down the stream tail foremost, the only fashion in which salmon descend to the sea. As already stated, in the head-waters of the large streams, unquestionably, all die; it is the belief of the writer that none ever survive. The young hatch in sixty days, and most of them return to the ocean during the high water of the spring. They enter the river as adults at the age of about four years.
The salmon of all kinds in the spring are silvery, spotted or not according to the species, and with the mouth about equally symmetrical in both sexes. As the spawning season approaches the female loses her silvery color, becomes more slimy, the scales on the back partly sink into the skin, and the flesh changes from salmon-red and becomes variously paler, from the loss of oil; the degree of paleness varying much with individuals and with inhabitants of different rivers. In the Sacramento the flesh of the quinnat, in either spring or fall, is rarely pale. In the Columbia a few with pale flesh are sometimes taken in spring, and an increasing number from July on. In Frazer River the fall run of the quinnat is nearly worthless for canning purposes, because so many are "white-meated." In the spring very few are "white-meated"; but the number increases towards fall, when there is every variation, some having red streaks running through them, others being red toward the head and pale toward the tail. The red and pale ones cannot be distinguished externally, and the color is dependent on neither age nor sex. There is said to be no difference in the taste, but there is little market for canned salmon not of the conventional orange-color.
As the season advances the difference between the males and females becomes more and more marked, and keeps pace with the development of the milt, as is shown by dissection. The males have (1) the premaxillaries and the tip of the lower jaw more and more prolonged, both of the jaws becoming finally strongly and often extravagantly hooked, so that either they shut by the side of each other like shears, or else the mouth cannot be closed. (2) The front teeth become very long and canine-like, their growth proceeding very rapidly, until they are often half an inch long. (3) The teeth on the vomer and tongue often disappear. (4) The body grows more compressed and deeper at the shoulders, so that a very distinct hump is formed; this is more developed in the humpback salmon, but is found in all. (5) The scales disappear, especially on the back, by the growth of spongy skin. (6) The color changes from silvery to various shades of black and red, or blotchy, according to the species. The blue-back turns rosy-red, the head bright olive; the dog-salmon a dull red with blackish bars, and the quinnat generally blackish. The distorted males are commonly considered worthless, rejected by the canners and salmon-salters, but preserved by the Indians. These changes are due solely to influences connected with the growth of the reproductive organs. They are not in any way due to the action of fresh water. They take place at about the same time in the adult males of all species, whether in the ocean or in the rivers. At the time of the spring runs all are symmetrical. In the fall all males, of whatever species, are more or less distorted. Among the dog-salmon, which run only in the fall, the males are hook-jawed and red-blotched when they first enter the Strait of Fuca from the outside. The humpback, taken in salt water about Seattle, have the same peculiarities. The male is slab-sided, hook-billed, and distorted, and is rejected by the canners. No hook-jawed females of any species have been seen.
On first entering a stream the salmon swim about as if playing. They always head towards the current, and this appearance of playing may be simply due to facing the moving tide. Afterwards they enter the deepest parts of the stream and swim straight up, with few interruptions. Their rate of travel at Sacramento is estimated by Stone at about two miles per day; on the Columbia at about three miles per day. Those which enter the Columbia in the spring and ascend to the mountain rivers of Idaho must go at a more rapid rate than this, as they must make an average of nearly four miles per day.
As already stated, the economic value of any species depends in great part on its being a "spring salmon." It is not generally possible to capture salmon of any species in large numbers until they have entered the estuaries or rivers, and the spring salmon enter the large rivers long before the growth of the organs of reproduction has reduced the richness of the flesh. The fall salmon cannot be taken in quantity until their flesh has deteriorated; hence the dog-salmon is practically almost worthless except to the Indians, and the humpback salmon was regarded as little better until comparatively recently, when it has been placed on the market in cans as "Pink Salmon." It sells for about half the price of the red salmon and one-third that of the quinnat. The red salmon is smaller than the quinnat but, outside the Sacramento and the Columbia, far more abundant, and at present it exceeds the quinnat in economic value. The pack of red salmon in Alaska amounted in 1902 to over two million cases (48 pounds each), worth wholesale about $4.00 per case, or about $8,000,000. The other species in Alaska yield about one million cases, the total wholesale value of the pack for 1902 being $8,667,673. The aggregate value of the quinnat is considerably less, but either species far exceed in value all other fishes of the Pacific taken together. The silver salmon is found in the inland waters of Puget Sound for a considerable time before the fall rains cause the fall runs, and it may be taken in large numbers with seines before the season for entering the rivers.
The fall salmon of all species, but especially of the dog-salmon, ascend streams but a short distance before spawning. They seem to be in great anxiety to find fresh water, and many of them work their way up little brooks only a few inches deep, where they perish miserably, floundering about on the stones. Every stream of whatever kind, from San Francisco to Bering Sea, has more or less of these fall salmon.
The absence of the fine spring salmon in the streams of Japan is the cause of the relative unimportance of the river fisheries of the northern island of Japan, Hokkaido. It is not likely that either the quinnat or the red salmon can be introduced into these rivers, as they have no snow-fed streams, and few of them pass through lakes which are not shut off by waterfalls. For the same reason neither of these species is likely to become naturalized in the waters of our Eastern States, though it is worth while to bring the red salmon to the St. Lawrence. The silver salmon, already abundant in Japan, should thrive in the rivers and bays of New England.
=The Parent-stream Theory.=—It has been generally accepted as unquestioned by packers and fishermen that salmon return to spawn to the very stream in which they were hatched. As early as 1880 the present writer placed on record his opinion that this theory was unsound. In a general way most salmon return to the parent stream, because when in the sea the parent stream is the one most easily reached. The channels and runways which directed their course to the sea may influence their return trip in the same fashion. When the salmon is mature it seeks fresh water. Other things being equal, about the same number will run each year in the same channel. With all this, we find some curious facts. Certain streams will have a run of exceptionally large or exceptionally small red salmon. The time of the run bears some relation to the length of the stream: those who have farthest to go start earliest. The time of running bears also a relation to the temperature of the spawning grounds: where the waters cool off earliest the fish run soonest.
The supposed evidence in favor of the parent-stream theory may be considered under three heads:[9] (1) Distinctive runs in various streams. (2) Return of marked salmon. (3) Introduction of salmon into new streams followed by their return.
Footnote 9:
See an excellent article by H. S. Davis in the Pacific Fisherman for July, 1903.
Under the first head it is often asserted of fishermen that they can distinguish the salmon of different streams. Thus the Lynn Canal red salmon are larger than those in most waters, and it is claimed that those of Chilcoot Inlet are larger than those of the sister stream at Chilcat. The red salmon of Red Fish Bay on Baranof Island are said to be much smaller than usual, and those of the neighboring Necker Bay are not more than one-third the ordinary size. Those of a small rapid stream near Nass River are more wiry than those of the neighboring large stream. The same claim is made for the different streams of Puget Sound, each one having its characteristic run. In all this there is some truth and perhaps some exaggeration. I have noticed that the Chilcoot fish seem deeper in body than those at Chilcat. The red salmon becomes compressed before spawning, and the Chilcoot fishes having a short run spawn earlier than the Chilcat fishes, which have many miles to go, the water being perhaps warmer at the mouth of the river. Perhaps some localities may meet the nervous reactions of small fishes, while not attracting the large ones. Mr. H. S. Davis well observes that "until a constant difference has been demonstrated by a careful examination of large numbers of fish from each stream taken at the same time, but little weight can be attached to arguments of this nature."
It is doubtless true as a general proposition that nearly all salmon return to the region in which they were spawned. Most of them apparently never go far away from the mouth of the stream or the bay into which it flows. It is true that salmon are occasionally taken well out at sea, and it is certain that the red salmon runs of Puget Sound come from outside the Straits of Fuca. There is, however, evidence that they rarely go so far as that. When seeking shore they do not reach the original channels.
In 1880 the writer, studying the salmon of the Columbia, used the following words, which he has not had occasion to change:
"It is the prevailing impression that the salmon have some special instinct which leads them to return to spawn in the same spawning grounds where they were originally hatched. We fail to find any evidence of this in the case of the Pacific-coast salmon, and we do not believe it to be true. It seems more probable that the young salmon hatched in any river mostly remain in the ocean within a radius of twenty, thirty, or forty miles of its mouth. These, in their movements about in the ocean, may come into contact with the cold waters of their parent rivers, or perhaps of any other river, at a considerable distance from the shore. In the case of the quinnat and the blue-back their 'instinct' seems to lead them to ascend these fresh waters, and in a majority of cases these waters will be those in which the fishes in question were originally spawned. Later in the season the growth of the reproductive organs leads them to approach the shore and search for fresh waters, and still the chances are that they may find the original stream. But undoubtedly many fall salmon ascend, or try to ascend, streams in which no salmon was ever hatched. In little brooks about Puget Sound, where the water is not three inches deep, are often found dead or dying salmon which have entered them for the purpose of spawning. It is said of the Russian River and other California rivers that their mouths, in the time of low water in summer, generally become entirely closed by sand-bars, and that the salmon, in their eagerness to ascend them, frequently fling themselves entirely out of water on the beach. But this does not prove that the salmon are guided by a marvelous geographical instinct which leads them to their parent river in spite of the fact that the river cannot be found. The waters of Russian River soak through these sand-bars, and the salmon instinct, we think, leads them merely to search for fresh waters. This matter is much in need of further investigation; at present, however, we find no reason to believe that the salmon enter the Rogue River simply because they were spawned there, or that a salmon hatched in the Clackamas River is more likely, on that account, to return to the Clackamas than to go up the Cowlitz or the Des Chûtes."
Attempts have been made to settle this question by marking the fry. But this is a very difficult matter indeed. Almost the only structure which can be safely mutilated is the adipose fin, and this is often nipped off by sticklebacks and other meddling fish. The following experiments have been tried, according to Mr. Davis:
In March, 1896, 5000 king-salmon fry were marked by cutting off the adipose fin, then set free in the Clackamas River. Nearly 400 of these marked fish are said to have been taken in the Columbia in 1898, and a few more in 1899. In addition a few were taken in 1898, 1899, and 1900 in the Sacramento River, but in much less numbers than in the Columbia. In the Columbia most were taken at the mouth of the river, where nearly all of the fishing was done, but a few were in the original stream, the Clackamas. It is stated that the fry thus set free in the Clackamas came from eggs obtained in the Sacramento—a matter which has, however, no bearing on the present case.
In the Kalama hatchery on the Columbia River, Washington, 2000 fry of the quinnat or king-salmon were marked in 1899 by a V-shaped notch in the caudal fin. Numerous fishes thus marked were taken in the lower Columbia in 1901 and 1902. A few were taken at the Kalama hatchery, but some also at the hatcheries on Wind River and Clackamas River. At the hatchery on Chehalis River six or seven were taken, the stream not being a tributary of the Columbia, but flowing into Shoalwater Bay. None were noticed in the Sacramento. The evidence shows that the most who are hatched in a large stream tend to return to it, and that in general most salmon return to the parent region. There is no evidence that a salmon hatched in one branch of a river tends to return there rather than to any other. Experiments of Messrs. Rutter and Spaulding in marking adult fish at Karluk would indicate that they roam rather widely about the island before spawning. An adult spawning fish, marked and set free at Karluk, was taken soon after on the opposite side of the island of Kadiak.
The introduction of salmon into new streams may throw some light on this question. In 1897 and 1898 3,000,000 young quinnat-salmon fry were set free in Papermill Creek near Olema, California. This is a small stream flowing into the head of Tomales Bay, and it had never previously had a run of salmon. In 1900, and especially in 1901, large quinnat salmon appeared in considerable numbers in this stream. One specimen weighing about sixteen pounds was sent to the present writer for identification. These fishes certainly returned to the parent stream, although this stream was one not at all fitted for their purpose.
But this may be accounted for by the topography of the bay. Tomales Bay is a long and narrow channel, about twenty miles long and from one to five in width, isolated from other rivers and with but one tributary stream. Probably the salmon had not wandered far from it; some may not have left it at all. In any event, a large number certainly came back to the same place.
That the salmon rarely go far away is fairly attested. Schools of king-salmon play in Monterey Bay, and chase the herring about in the channels of southeastern Alaska. A few years since Captain J. F. Moser, in charge of the Albatross, set gill-nets for salmon at various places in the sea off the Oregon and Washington coast, catching none except in the bays.
Mr. Davis gives an account of the liberation of salmon in Chinook River, which flows into the Columbia at Baker's Bay:
"It is a small, sluggish stream and has never been frequented by Chinook salmon, although considerable numbers of silver and dog salmon enter it late in the fall. A few years ago the State established a hatchery on this stream, and since 1898 between 1,000,000 and 2,000,000 Chinook fry have been turned out here annually. The fish are taken from the pound-nets in Baker's Bay, towed into the river in crates and then liberated above the dike, which prevents their return to the Columbia. When ripe the salmon ascend to the hatchery, some two or three miles farther up the river, where they are spawned.
"The superintendent of the hatchery, Mr. Hansen, informs me that in 1902, during November and December, quite a number of Chinook salmon ascended the Chinook River. About 150 salmon of both sexes were taken in a trap located in the river about four miles from its mouth. At first thought it would appear that these were probably fish which, when fry, had been liberated in the river, but unfortunately there is no proof that this was the case. According to Mr. Hansen, the season of 1902 was remarkable in that the salmon ran inshore in large schools, a thing which they had not done before for years. It is possible that the fish, being forced in close to the shore, came in contact with the current from the Chinook River, which, since the stream is small and sluggish, would not be felt far from shore. Once brought under the influence of the current from the river, the salmon would naturally ascend that stream, whether they had been hatched there or not."
The general conclusion, apparently warranted by the facts at hand, is that salmon, for the most part, do not go to a great distance from the stream in which they are hatched, that most of them return to the streams of the same region, a majority to the parent stream, but that there is no evidence that they choose the parental spawning grounds in preference to any other, and none that they will prefer an undesirable stream to a favorable one for the reason that they happen to have been hatched in the former.
=The Jadgeska Hatchery.=—Mr. John C. Callbreath of Wrangel, Alaska, has long conducted a very interesting but very costly experiment in this line. About 1890 he established himself in a small stream called Jadgeska on the west coast of Etolin Island, tributary to McHenry Inlet, Clarence Straits. This stream led from a lake, and in it a few thousand red salmon spawned, besides multitudes of silver salmon, dog-salmon, and humpback salmon. Making a dam across the stream, he helped the red salmon over it, destroying all of the inferior kinds which entered the stream. He also established a hatchery for the red salmon, turning loose many fry yearly for ten or twelve years. This was done in the expectation that all the salmon hatched would return to Jadgeska in about four years. By destroying all individuals of other species attempting to run, it was expected that they would become extinct so far as the stream is concerned.
The result of this experiment has been disappointment. After twelve years or more there has been no increase of red salmon in the stream, and no decrease of humpbacks and other humbler forms of salmon. Mr. Callbreath draws the conclusion that salmon run at a much greater age than has been supposed—at the age of sixteen years, perhaps, instead of four. A far more probable conclusion is that his salmon have joined other bands bound for more suitable streams. It is indeed claimed that since the establishment of Callbreath's hatchery on Etolin Island there has been a notable increase of the salmon run in the various streams of Prince of Wales Island on the opposite side of Clarence Straits. But this statement, while largely current among the cannerymen, and not improbable, needs verification.
We shall await with much interest the return of the thousands of salmon hatched in 1902 in Naha stream. We may venture the prophecy that while a large percentage will return to Loring, many others will enter Yes Bay, Karta Bay, Moira Sound, and other red salmon waters along the line of their return from Dixon Entrance or the open sea.
=Salmon-packing.=—The canning of salmon, that is, the packing of the flesh in tin cases, hermetically sealed after boiling, was begun on the Columbia River by the Hume Brothers in 1866. In 1874 canneries were established on the Sacramento River, in 1876 on Puget Sound and on Frazer River, and in 1878 in Alaska. At first only the quinnat salmon was packed; afterwards the red salmon and the silver salmon, and finally the humpback, known commercially as pink salmon. In most cases the flesh is packed in one-pound tins, forty-eight of which constitute a case. The wholesale price in 1903 was for quinnat salmon $5.60 per case, red salmon $4.00, silver salmon $2.60, humpback salmon $2.00, and dog-salmon $1.50. It costs in round numbers $2.00 to pack a case of salmon. The very low price of the inferior brands is due to overproduction.
The output of the salmon fishery of the Pacific coast amounts to about fifteen millions per year, that of Alaska constituting seven to nine millions of this amount. Of this amount the red salmon constitutes somewhat more than half, the quinnat about four-fifths of the rest.
In almost all salmon streams there is evidence of considerable diminution in numbers, although the evidence is sometimes conflicting. In Alaska this has been due to the vicious custom, now done away with, of barricading the streams so that the fish could not reach the spawning grounds, but might be all taken with the net. In the Columbia River the reduction in numbers is mainly due to stationary traps and salmon-wheels, which leave the fish relatively little chance to reach the spawning grounds. In years of high water doubtless many salmon run in the spring which might otherwise have waited until fall.
The key to the situation lies in the artificial propagation of salmon by means of well-ordered hatcheries. By this means the fisheries of the Sacramento have been fully restored, those of the Columbia approximately maintained, and a hopeful beginning has been made in hatching red salmon in Alaska.