ne seen ented c eS RST Oe Tanncis Ge sound Senne ag Ane Ny) Yuna) ) ' H f y W. B. FROSTICK 26 MINSTER PRECINCTS PETERBOROUGH an" —. 7 bn dg Sead ‘ve Fi Fil : oe an or te Oars AZ : 4 aed ; a er << Pa z Pe - 3 i re ai : a ® 4 ire 7 aera kt it > } . 1 a i : Rs ; _ " m eA 7 , a Cone Lar, ay a oo) yt big vee! a a : 4 aS Wy - { LU Ree ‘ dy Sih) * ‘ 7 a y Nas @ can ! : X - ¥ [ i" % 1 - 2 imi e * >» a i 3 > e a af ; ; 7 — @ ea oi 1 7 “- 4 _,. «& i- = Po +. e ~ ’ ss vs 6 V Sage. - a ; > ru ae ‘a Fi i Pl A : . 7 ” = e ¥ ¥ ii 7 é « . . ue - ? y : 7 : - q ‘ i Fl 7 a ‘ : ‘ ; : P ; t ; * - . of t iy : a a a ‘ Fi J. 4 ss = ‘a ue : 7 4 1 - f i } iy - i € 5 1 , t ae : . ’ ' ; - ' ‘ ' / Fi : A 1 7 a : ’ : 7 ‘ ¢ f : ; : ’ 1 A os : a Ne T “he ra ¥ , 7 7 a” a. (7 ri ' 0 ~ E. », é é ‘ 3 7 : ' * ‘ . 1 s ; Gs : : : ; ; i yin & - a : : j ’ ‘ s : , :> ; : os ¥ 7. a a 7 7 ye Lf ‘ , . ' = > ‘ ‘ - "7 & ‘ - 4 . . 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J ‘ | ; \ . 5 a “ é q wy - ’ . a > a - - es ‘ ». 5 5 ) ; -/ j uy - >" _*s a FI f 4 , | a +) a ; ys : an ’ | i v : . ; ; is ’ 4 2 , 7 , . p vs fom oes Lene 4 aaa, 9 OY v , tas fr ae | Po.c¥. ” ‘ rte RORY Al iol AT Els Porm y e any ai, ie ee Vib. ye Ve 7 wae af j no ae, ma f Ly * "| is a ns a A i y , by Wat Wert ays (i Pyne , i? arin Wy : DA i ir an ‘a A ee amen e ‘ < ’ SF; awe Ny A ‘J ; a, apa Tadallth [ae NATURAL HISTORY EDITED! {Bir RICHARD. LVDEKMERS Bass vo Res:, Ee: With) RRERACE. By ele) SCIVATER EMAs. Pio. Reo Ere. SECRETARY OF THE ZOOLOGICAL SOCIETY OF LONDON ILLUSTRATED WITH Seventy-two Coloured Plates and Sixteen Hundred Engravings BY W. KUHNERT, F. SPECHT, P. J. SMIT, G. MUTZEL, A. T. ELWES, J. WOLF, GAMBIER BOLTON, F.Z.S.; AND MANY OTHERS V Oil Sib) CALA ORN exe LONDON Pee DH RICK. WARNE 6&6 6.C.O; INAISAD IRI \Wr NGCO)Anale 1896 [All Rights Reserved} e ii oe y of “ Hi = keg - / 7 - Nie 7 i ae MORRISON AND GIBB, PRINTERS, EDINBU. CON PEN TES AMPHIBIANS CHAPTER IIL—NeEwts, SALAMANDERS, AND CacILians,—Orders Caudata and Apoda. Distinctive Characters of the Caudata—Their Distribution and Habits—The Salamander Tribe (Salamandridw)—Typical Salamanders (Salamandra)— Alpine Salamander— Spanish Salamander (Chioglossa)—Newts (Molge)—Crested Newt—Marbled Newt— Alpine Newt—Common Newt—Webbed Newt—Other Species—Habits of Newts— Spectacled Salamander (Salamandrina)—Other Genera (Tylotriton and Pachytriton)— Axolotls (Amblystoma)—Other Genera—The Fish-Like Salamanders (A mphiumide)— Giant Salamander (Megalobatrachus) — Hell-Bender (Cryptobranchus) —Three-Toed Salamander (Amphiuma)— The Gilled Salamanders (Proteidw)—Olm (Proteus) — Furrowed Salamander (Nectuwrus)—Two-Legged Salamanders (Sirenidw~)—The Ceecil- jans, or Worm-Like Amphibians (Order Apoda), . CHAPTER III.—THe PrimEvat SALAMANDERS,—Order Labyrinthodontia. Characters and Distribution of the Group—The Leading Families and Genera, States CHAPTER I.—GENERAL CHARACTERISTICS OF THE CLASS PISCES. CLASSIFICATION—External Skeleton—Internal Skeleton—Teeth—Coloration—Soft Parts— Reproduction—Tenacity of Life—Distribution, . CHAPTER II.—Lune-FisHes anp Cuim&roips,—Subclasses Dipnot and Holocephali. Existing Lung-Fishes (Lepidosirenidw)—Australian Lung-Fish (Ceratodus)—South American Mud-Fish (Lepidosiren)—African Mud-Fish (Protopterus)—Extinct Lung-Fishes—Berry- Bone Fishes (Order Arthrodira)—The Chimeroids (Subclass Holocephalt), CHAPTER III.—Tuer Bony Fishes AND GANOIDS,—Subclass Teleostomt. Classification—Fan-Finned Group (Order Actinopterygii)—Spine-Finned Fishes (Suborder Acanthopterygit)—The Perch Tribe (Percide)—True Perches (Perca)—Pike-Perches (Lucioperca)—Danubian Perches (Aspro)—Ruftes (Acerina)—Centrarchide—Bass and Sea-Perches (Serranidw)— South American Perch and Bass (Percichthys and Morone)— Sea-Perch (Centropristes, Serranus, etc.) —Stone-Bass (Polyprion)—Oriental and African Perches (Lates and Psammoperca)—Scaly-Finned Fishes (Chetodontide)—Chetodon— Ohelmon—Heniochus—Holacanthus—Red Mullets (Mullide)—Sea-Breams (Sparide)— Cantharus—Haplodactylus—Sargus—Gilt-Heads (Chrysophrys) — Knife-Jawed Fishes (Hoplognathide)—Thick-Rayed Fishes (Cirrhitide) — Cirrhitichthys — Chilodactylus— Scorpenoids (Scorpenidw)—Allied Families—Berycoids, or Slime-Heads (Berychidw)— Curtide and Polynemide —Scienoids (Scienide)— Drum (Pogonias) — Umbrines PAGE 289 311 314 Vill CONTENTS. (Umbrina)—Meagres (Sciwna)—Sword-Fishes (Xiphiide)—Scabbard-Fishes and Hair- Tails (Trichiwride)—Scabbard-Fish (Lepidopus)—Hair-Tails (Trichiurus) Barracudas (Thyrsites)—Extinct Forms—Surgeons (Acronuridw)—Horse-Mackerels (Carangide)— Typical Group (Caranz)—Pilot-Fish (Naucrates)—Sea-Bats (Platax)—Dories (Cyttide) —Stromateids and Coryphenas (Stromateide and Coryphenide) —Coryphena—Sun-Fish (Lampris)—Nomeids (Nomeide)—Mackerels (Scomberidw)— Thunnies (Thynnus)— Sucking-Fishes (Hcheneis)—Star-Gazers and Weavers (Trachinide)—Uranoscopus— Trachinus—Tile-Fish (Lopholatilus)— Other Groups—Soft-Spines and Frog-Fishes (Malacanthide and Batrachide)—Batrachus—Angler-Fish and their Alles (Lophiide) —Anglers (Lophius)—Tentacle-Fish (Antennarius)—Bull-Heads and Gurnards (Cot- tide—Bull-Heads (Cottus)—Gurnards (Trigla)—Beaked Gurnards (Peristethus)—F lying Gurnards (Dactylopterus)—Dragon-Fishes (Pegasus)—Lump-Suckers (Cyclopteridw)— Gobies and Mud-Skippers (Gobiide)—Gobius—Periophthalmus—Band-Fishes (Cepolide) —Hairy-Backs (Trichonotide)—Chiride—Blennies (blenniide)—Viviparous Blennies (Zoarces)—Wolf-Fishes (Anarrhichas)— Oblique-Spined Blenny (Acanthoclinidw)— Spiny Eels (Rhynchobdellide)—Oil-Fish (Comephorus)—Barracuda-Pikes (Sphyrenide)— Sand-Smelts (Atherinidw)—Square-Tail (Tetragonurus)—Grey Mullets (Mugilidw)— Gar-Pike and Flying-Fish (Scombresocidw)—Gar- Pike (Lelone)—Flying-Fish (Hzocetus) —Sticklebacks (Gustrosteidw) — Flute-Mouths (Aulostomatide)—Trumpet-Fish (Cen- triscide)—Sucker-Fishes (Gobioesocidw)—Serpent-Heads (Ophiocephalide)—Labyrinth- Gilled Fishes (Anabantide and Luciocephalide)—Climbing-Perch (A nabas)—Paradise- Fish (Polyacanthus)—Gurami (Osphromenus)—Fighting-Fish (Betta)—Unicorn-Fish (Lophotida)—Ribbon-Fish (Trachypteride)—Thornbacks (Notacanthide)—Pomacentride —Wrasses (Labridw)—True Wrasses (Labrus)—Parrot-Wrasses (Scarus)—Viviparous Wrasses (Diatrematide)—Chromids (Chromididw)—Tuft-Gilled Fishes (Suborder Lopho- branchit)—Mailed Tube-Mouths (Solenostomatide)—Pipe-Fishes and Sea-Horses (Syn- gnathide) —Comb-Gilled Group (Suborder Plectognath’) — File-Fishes and Coffer- Fishes (Balistide)—Globe-Fishes and Sun-Fishes (Diodontide)—Soft-Finned Fishes (Suborder Anacanthini)—Lycodide—The Cod Tribe (Gadide)—True Cod (Gadus)— Haddock—Other Species—Hakes (Merluccius)—Burbot (Lota)—Ling and Rockling (Molva)—Sand-Kels and their Allies (Ophidiide)— Cave-Fish (Lucifuga) — Snake- Fishes (Ophidiwm)—Parasitic Fish (Fverasfer)—-Sand-Eels (Ammodytes)—Conyrodus— The Long-Tails (Macruridw)—Flat-Fishes (Pleuronectidw)—Psettodes—Holibut (Hippo- glossus)—Turbot, ete. (Rhombus)—Plaice and Flounder (Plewronectes)—Soles (Solea)— Blind Soles (Soleotalpa)—The Tube-Bladdered Fishes (Suborder Physostomi)—Eel Tribe (Murenide)—Murenas (Murena)—True Eels (Anguilla)—Congers (Conger)— Serpent-Eels (Ophichthys)—Deep-Sea Eels (Synaphobranchus)—Single-Slit Eels (Sym- branchidew)—Electric Eel (Gymnotidw) — Cat-Fishes (Siluridw)— Eel-Like Cat-Fish (Clarias)—Wels (Silurus)—Yarrell’s Cat-Fish (Bagarius)—Electrie Cat-Fishes (Mala- pterurus)—Mailed Cat-Fishes (Callichthys, ete. —Carp Tribe (Cyprinidw)—-True Carp (Cyprinus)—Crucian and Golden Carp (Carassius)—Barbels (Barbus)—Gudgeon (Gobio) —White-Fish (Leuciseus)—Tench (Tinca)—Beaked Carp (Chondrostoma)—Bitterling (Khodeus)—Bream (Abramis)—Rapfen (Aspius)—Bleak (Alburnus)—Sichel (Pelecus) Loaches (Cobitis, etc.)—African Loaches (Kneriid~)—Characinoid Fishes (Erythrinide) Cyprinodonts (Cyprinodontide)—Double-Eyes (Anableps)—Blind-Fish (A mblyopside) Umbres (Umbridw)—Pike (Esocide)—African Beaked-Fish (Mormyride)—Feather- Backs (Notopteridw) — Southern Pikelets (Galaxiide) — Arapaimas (Osteoglossidw)— Arapaima (Arapaima)—Barbelled Avapaima (Osteoglosswm)—Small-Mouthed Arapaima (Heterotis)—Moon-Eye (Hyodontide) — Chisel-Jaw (Pantodontide) —Beaked Salmon (Gonorhynchidw)—The Scopeloids (Scopelide)—Phosphorescent Scopeloids (Sternopty- chide and Stomateide)—Silvery Light-Fish (Photichthys)—Hedgehog-Mouths (Echio- stoma)—The Dorab (Chirocentride) — Long-Finned Herring (Bathythrisside) — The Extinct Saurodonts (Enchodontide, Saurocephalide, ete.)—The Herring Tribe (Clupeide) —Typical Group (Clupea)—Fresh-Water Herrings (Diplomystus)—Anchovies (Engraulis) PAGE CONTENTS 1X PAGE —Elops—Slender-Scales (Leptolepis)—The Smooth-Heads (Alepocephalide)—Southern Salmon (Haplochitonide)—Salmon Tribe (Salmonidew)— Typical Group (Salmo)— Salmon—Trout—Charr—Many-Rayed Salmon (Onchorhynchus)—Smelts (Osmerus)— Coregonoids (Coregonus)—Grayling (Thymallus)—Percopside —Bony Pike and_ its Kindred (Suborder ttheospondyli) — Existing Types (Lepidosteidw) — Spear-Beaks (Aspidorhynchide)—The Bow-Fin and its Allies (Suborder Protospondyli)—Existing Family (Amiidw)—Extinct Families (Pachycormide, ete.)—The Sturgeon Tribe (Sub- order Chondrostei)—Toothed Sturgeons (Polyodontidw)—Toothless Sturgeons—(A cipen- seride)—True Sturgeons (Acipenser)—Shovel-Beaked Sturgeons (Scaphirhynchus)— Allied Extinct Families (Chondrosteide, ete.)—Fringe-Finned Ganoids (Order Cros- sopterygit)— Existing Species (Polypteridw)—Extinct Families, . ; : . 333 CHAPTER IV.—SHarks and Rays,—Subclass Elasmobranchii. Distinctive Features—The Blue Shark and its Allies (Carchariidw)—Typical Genus (Car- charias)—Tope (Galews)—Hammerheads (Sphyrna)—Hounds (Mustelus)— Porbeagle Group (Lamnide) —Porbeagles (Lamna)—Rondeleti’s Shark (Carcharodon)—Fox-Shark (Alopecias)—Basking-Shark (Cetorhinus)—Indo-Pacitic Basking-Shark ([hinodontide) —Dog-Fishes and Their Allies (Scylliidw)—True Dog-Fishes (Scylliwm)—Other Genera—Pavement-Toothed Sharks (Cestraciontidw)—Comb-Toothed Sharks (Noti- danide)—Typical Genus (Notidenus) — Frill-Gilled Shark (Chlamydoselache) — The Spiny Dog-Fishes and their Allies (Spinacide)—The Extinct Petalodonts (Petalodon- tide)—The Angel-Fish (Squatinide)—The Saw-Fishes (Pristiophoridw and Pristide)— Side-Gilled Saw-Fishes (Pristiophorus) — True Saw-Fishes (Pristis)—Beaked Rays (Rhinobatide)—Typical Genus (Rhinobatis)—Rhynchobatis—The True Rays, or Skates (Raiide)—Electric Rays (Torpedinide)—The Eagle-Rays (Myliobatidw)—Typical Genus (Myliobatis)—Other Genera (Aétobatis, etc.)—Sting-Rays (T'rygonidw)—Lobe-Finned Sharks (Ichthyotom’) — Fold- Finned Sharks (Cladodontia)— Spine - Finned Sharks (Acanthodiz), : : : ; , : : : ~ +520 Pie rEOWEST VERTEBRATES AND THiEis AINE CHAPTER I.—Tur Lamprey Grovup,—Class Cyclostomata. CHARACTERS OF CHORDATES AND Non-CHorpates—Lampreys aud Hag-Fishes (Subclass Marsipobranchii)—True Lampreys (Petromyzwm)—Southern Lampreys (Mordacia, ete.) —Hag-Fishes (Myxinide)—Primeval Lampreys (Palwospondylus), : ; . 549 CHAPTER II.—TuHE ARMovRED PRIMEVAL VERTEBRATES,—Subclass Ostracophori. _ Pteraspis—Cephalaspis—Pterichthys, : : - : : : ‘ . 555 CHAPTER III.—Tue Lancerers,—Subkingdom Protochordata—Class Leptocardii. Common Lancelets (Branchiostoma), 3 : : ; : . 558 CHAPTER IV.-—TuHe Sea-Squirts or Ascrpians,—Class Tunicata. Structure of Ascidians—Development—Typical Ascidians—Non-Luminous Pelagic Ascidians —Tailed Ascidians, : : : : : ; : : . v6 CHAPTER V.—Worm-LikEe ProtocHorDATEs,—Class Jinteropneusta. Balanoglossus—Other Forms—Ancestry of Chordates, . : ~ 40re InDEx to FirrH VouumMs, comprising Sections IX. and X. : ; , : wo) bist OF LELUSTRA ies COLOURED es Aai => A Satmon Lear,. CHIMERA, . GURNARDS, : GLOBE-FISH AND One FIsH, . Fuat-FIsuH, BLUE SHARK, Frontispiece Facing page 332 i, Ses » 428 » 441 ~~ B22 PAGE sre Avr GRoupP OF ScALY-FINNED FISHES, GIANT AND COMMON STURGEONS, Page 342 » dll Facing ,, ASCIDIANS, 549 DEXT ENGRAVINGS AMPHIBIANS PAGE PAGE Alpine Newts, 289 | Hell-Bender, or Mississippi Salamander, . 305 Spotted Salamander, 292 | Three-Toed, or Eel-Like Salamander, 306 Alpine Salamander, : 293 | The Olm, 307 Male and Female of Marbled News 295 | Siren Salamander, . 309 Male and Female of Common Newt, 297 | A Worm-Like Aerie plan, : 310 Spectacled Salamander, ; 299 | Skeletons of Primeval Salamanders, Bult Larval Stage of Mexican Axolotl, . 300 | Skull of Mastodonsaur, 312 Adult of Mexican Axolotl, 301 | Vertebre of Primeval Salanandes 312 Giant Salamander, 303 ! Skull of Metoposaur, oll ESICSEIGES:S) PAGE PAGE Flying Fish, 314 | African Mud-Fish, 329 Skeleton of Perch, . . 316 | Restoration of Berry-Bone Fish, 331 Skeleton of Extinct eee ceed Shark, 317 | Pike-Perch and Common Perch, 334 Skeleton of Sturgeon, . 3818 | Danubian Perches and Ruffe, 337 Skeleton of Fin of Fringe- Finned Shark, 319 | Common Bass, Sea-Perch, and Stone-Bass, 339 Skull of Australian Lung-Fish, 325 | Striped Red Mullet, 345 Palatal Teeth of Extinct Lung-Fish, 326 | Sargo and Gilt-Head, 347 Australian Lung-Fish, 327 | Australian Knife-Jawed Fish, 348 South-American Mud-Fish, 328 | Spotted Firm-Fin, . 349 LUST. Australian Long-Fin, Bleeker’s Plesiops, . Schomburgk’s Many- Shots Group of Spine-Finned Fishes, New Zealand Trachichthys, Common Meagre, Spotted Indian Sword- Fish, Scabbard-Fish, Common Mackerel and Horse- Mackerel Pilot-Fish, . Coryphzena, New Zealand Geman Sucking-Fishes, Star-Gazer and Weaver, Tile-Fish, Heedt’s Soft-Spine, Barracuda and Angler-Fish, Common Bull- Heads, Sapphirine Gurnards, Armed Bull-Head, Beaked Gurnard, Australian Dragon-Fish, Lump-Sucker and Viviparous Blenny, Fresh-Water Goby, Mud-Skippers Disporting, New Zealand Thorny- Nose, Japanese Chirus, Oblique-Spined Blenny, Indian Spiny Eel and Oil-Fish, Sand-Smelt and Square-Tail, Common Grey Mullet, Gar- Pike, Group of Siiklcbacks, Two-Spotted Sucker-Fish, . Striated Serpent-Head, Climbing-Perch on Land, . Paradise-Fish and Telescope-Fish, The Gurami, Pike-Head, Unicorn-Fish, Banks’s Ribbon-Fish, Risso’s Thornback, . Silver-Dotted Pomacentrus, Striped Wrasse, : Silvery Viviparous Wrasse, Tristram’s Chromid, Blue-Finned Tube-Mouth, Pipe-Fish and Sea-Horse, Fucus-Like Sea-Horse, Eel-Like Lycodes, . Haddock, Whiting, and Cod, Burbot and Wels, . ‘ Parasitic Fish in Pearl-Shell, Lesser Sand-Eel, OF ILL OSTRATIONS Mediterranean Murzna, Eels in the Mud, Bengal Short-Tailed Eel, Electric Eel, Group of Carp, Group of White-Fish, Tench, Bitterling, Bleak, and Gudecen Group of Bream, : Sichel, Rapfen, and Beakeedl Carp, Group of Loaches, . , Angola Loach, The Piraya, Head of Cy peaedoun Female and Male Double-Eye, Kentucky Blind-Fish, Common Pike, ; : Beaked Fish and Slender Pikelet, Bornean Feather-Back, Brazilian Arapaima, : Chisel-Jaw and Moon- ae Beaked Salmon, Phosphorescent Sardine, Silvery Light-Fish and Hedgehog-Mouth, The Dorab, Long-Finned Herring, Skeleton of a Saurodont, Shad, Sprats, and Herring, Black Smooth-Head, Zebra Salmon, Salmon and Sea-Trout, May-Trout and Hucho, Grayling and Charr, Common Smelt, Maranes, Bony-Pike, . The Bow-Fin, Skeleton of Extinct Meni Jaw of Pycnodont, . Giant Scale-Tooth,. Spoon-Beaked Sturgeon, Sterlet, Extine Acrenecrsd Bish, The Bichir, ; Skeleton of Hollow- Spmed Ganeid: Hammer-Headed Shark, : Spiny Dog-Fish and Smooth-Hound, Indo-Pacific Basking-Shark, Lesser Spotted Dog-Fish and its Eggs, Port Jackson Shark, Lower Jaw of Port Jackson Shark, Teeth of Comb-Toothed Sharks, Frill-Gilled Shark, Angel-Fish, X11 MLS MOT? LIL CS LRALL ONS: PAGE PAGE Japanese Saw-Fish, ; ; . 587 | Common Skate and Marbled Electric Ray, 542 Halavi Ray, : , : . 5389 | Teeth of Lobe-Finned Shark, : . 546 Thornback Skates, : . 540 | Restoration of Fold-Finned Shark, - 54% Jaws of Thornback, , . 541 | Restoration of Spine-Finned Shark, . 547 WHE (LOWEST VibRT a BRATES AND VEE sA0l gE S| PAGE PAGE Group of Lampreys, : ; . 951 | A Cartilaginous Sea-Squirt (Phallusia), . 565 Hag-Fish, . ; . 553 | Pear-Shaped Ascidian (Hypobythius), . 566 Skeleton of Primeval Lamprey, . . 554 | A Creeping Ascidian (Clavelina), . #6 Restoration of Pteraspis, . ; . 555 | An Incrusting Ascidian (Botrylloides), . 568 Restoration of Cephalaspis, : . 556 | A Compound Ascidian (Amarucium), . 568 Restoration of Pterichthys, . ; . 556 | An Individual of a Chain-Salpa, . DAO Lancelet, . : ; ; . 658 | Botryllus, . : : : . 872 A Leathery Sea-Squirt (Aicrocosmus), . 561 | Young Balanoglossus, : 5 . 573 Section of Sea-Squirt, : : . 662 1 A Pyrosoma Colony, : : 576 ERRATA PAGE 7. Line 18 from top, after “yet” add “except in the leathery turtle.” 77. Line 4 from top, for “ rib-process” read “ rib-like process.” 79. Lines 2 and 3 from top, for “the majority of the vertebra of the tail have the articular cup behind and the ball in front” read “the nuchal bones give off rib-like processes underlying the marginals.” . 169. Line 6 from bottom, for “31” read “83.” 178. Line 10 from bottom, for “ African” read “ Oriental.” 180. Lines 21 and 22 from bottom, transpose “upper” and “ lower.” 186. Line 12 from bottom, for “ New Island” read “ New Ireland.” 245. Line 7 from top, for “heavy” read “ horny.” 266. Line 4 from top, for “ Australia” read “ Papua.” 273. Line 12 from bottom, after “and” add “almost.” 274. Line 8 from top, for “vertical” read “ horizontal.” 302. Line 4 from top, for “ Hypnobius” read “ Hynobius” ; line 22, omit “only.” 333. In table, delete “(6) Suborder IsosponpyLi—Leptolepis” ; and on p. 334, line 7 from top, for “eight” read “seven.” ; 362, 397. The species of Thyrsites and Sphyrena ave both termed “barracudas” ; the latter may be distinguished as “barracuda-pikes.” The account of the fishing of the latter refers to the former. 527. Line 29 from top, for “Iceland” read “ Treland.” > 2 . x : 2 . eee ery ee ” 532. Line 25 from bottom, instead of “four... five or six” read “five . . . SIX or seven. 534. Line 2 from top, for “developed” read “ depressed.” CRAP EER, NEwrTs, SALAMANDERS, AND Ca@cILIANS,— Orders CaAUDATA AND APODA. ALPINE NEWTS. THE newts and salamanders are readily distinguished from the frogs and toads by the retention of the tail throughout life. Hence they are collectively designated the Tailed Amphibians. Although they have generally two pairs of limbs, in a few instances the hind pair is wanting; and in all cases the bones of the limbs are of a normal type, the radius and ulna in the front pair, and the tibia and fibula in the hind ones remaining distinct from one another. In the skull the frontal bones are not united with the parietals, and the palatine bones are distinct from the jaw- bones or maxillz. Generally more or less lizard-like in form, the Tailed Amphibians undergo a less marked metamorphosis than the tailless group, some even retaining gills throughout life. As regards their geographical distribution, the salamanders and newts, of which there are rather more than one hundred and twenty existing species, are mainly characteristic of the Northern Hemisphere, being represented only by a few scattered forms in the Southern Hemisphere, and quite unknown in Africa south of the Sahara and in Australasia. The northern part of the Old World is the home of the true newts, of which four species extend into Northern Africa ; and it likewise contains one of the fish-like salamanders and the olm. ‘True VOL. V.—1I9 290 NEWTS AND SALAMANDERS. newts are very abundant in the western portion of this region, but as we proceed eastwards they become less numerous, and we notice an approximation to American types of the order, although only two genera are common to the Old and New Worlds. North America is especially rich in Tailed Batrachians, containing more than half the representatives of the entire suborder, and having the two- legged salamanders (Sirenide) peculiar to it. Axolotls are here especially abundant, and there are also peculiar genera belonging to the families of the fish-like and gilled salamanders. The Oriental region possesses only two species, namely, a peculiar genus (Tylotriton) of newts in Yunan and the Eastern Himalaya, and an axolotl in Siam. Tropical America, on the other hand, has ten species; among which may be specially noticed the newts of the genus Spelerpes, which are also represented by one species from Central America and the West Indies, and two others from the mountains of Colombia, Ecuador, and Northern Peru. Geologically, the group is by no means an old one, its earliest known representative (Hylwobatrachus) occurring in the Wealden strata of Belgium ; and these animals do not appear to have become abundant until the Tertiary epoch. Nearly all newts and salamanders appear to be inhabitants of water during at least some period of their existence; some frequenting muddy swamps, and others deep lakes or subterranean waters, while a few are found in mountain-tarns at elevations of several thousand feet above the sea. Without exception nocturnal in their habits, spending the day in slumber either concealed in hiding-places on land, or at the bottom of the water in their aquatic haunts, and venturing abroad only at evening or after heavy rain, they are all difficult of observation, and consequently much still remains to be learnt with regard to their mode of life. The terrestrial species generally frequent soft, shady, damp spots, but occasionally narrow valleys or forests where they conceal themselves under stones or fallen trunks of trees, or in holes in the earth. During their permanent or temporary sojourn in the water, the adults of those species unprovided with external gills are obliged to come periodically to the surface in order to breathe; and while in that element all are less completely nocturnal than when on land. Such species as are inhabitants of cold regions undergo a period of torpidity during the winter months; while in tropical regions others become quiescent when their haunts are dried up. They exhibit a wonderful tenacity of life; and when dried up in mud, or frozen in ice, will awaken at the first shower of rain, or when their icy bonds are dissolved by the sun’s rays. They have also the capacity of reproducing lost limbs, apparently any number of times. Although on land the majority of species are slow and sluggish in their movements, some salamanders from the south and west of Europe, belonging to the genera Salamandrina and Chioglossa, run with the celerity of lizards; while others, again, climb sloping or perpendicular faces of rock, like geckos. In the water all swim quickly, mainly by means of serpentine movements of the tail; although the water-newts are perhaps the most expert swimmers. All are carnivorous in their diet, feeding chiefly upon molluscs, worms, spiders, and insects. Their breeding-habits are peculiar in that there is usually no union between the two sexes; the females seizing the packets of spermatozoa deposited by the males, and conveying them to their own reproductive chambers. While some species lay eggs, in other cases the eggs are hatched within the bodies of the DSI SALAMANDERS. 291 female parent, and the tadpoles born alive, sometimes in a highly advanced stage of development. In the case of the common salamander, during the breeding-season the male enters the water first, and is followed shortly afterwards by the female, who gives birth to her tadpoles; but in the Alpine salamander, the young are born on land. The water-newts, on the other hand, lay eggs which are attached ‘to the stems and leaves of aquatic plants. The majority of the terrestrial forms pass the earlier stages of their existence in the water, not leaving this element till their lungs have become fully developed. In the tadpole-stage all the members of the order are remarkably alike; and this resemblance forbids any wide separation of species like the olm, in which the external gills are retained, from the true newts and salamanders, in which these appendages are lost at an early period. Although some of the larger kinds prey upon small fish, none of the newts and salamanders can be said to be harmful to man; while the terrestrial forms are defended against all foes, except fish, frogs, and snakes, by the poisonous secretion exuded by the glands of their skins; water-newts are, however, devoured by aquatic birds and mammals. The reputed noxious characters of the common salamander, and its alleged immunity to the effects of fire, are, of course, purely fabulous. The existing members of the order are divided into four families. THE SALAMANDER TRIBE. Family SALAMANDRIDZ. Comprising the typical members of the order, this family is specially char- acterised by the absence of gills in the adult condition, the presence of upper jawbones or maxillz, as well as of teeth in both the upper and lower jaws, and likewise by the development of distinct eyelids. The family, which includes by far the great majority of the order, is divided into four subfamilies; the first of which is characterised by having the teeth on the palate of the skull arranged in two longitudinal series, diverging posteriorly, and inserted on the inner margin of two backwardly-prolonged processes of the palatine bones. The median parasphenoid bone on the base of the skull is devoid of teeth, and the bodies of the vertebree are convex in front and concave behind. Typical The typical genus of the first subfamily (Salamandrine) is Salamanders. represented by three species, ranging from Central and Southern Europe to the Caucasus, Syria, and Algeria, of which the best known is the common spotted salamander (Salamandra maculosa). As a genus, these salamanders are characterised by the large and suboval tongue being free on the sides, and to a small degree also behind; by the palatine teeth forming two curved series ; by the presence of four front and five hind-toes; and likewise by the nearly cylindrical section of the tail. The spotted species, which varies in length from 7 to 9 inches, may be recognised by the length of the tail being slightly less than that of the head and body, and still more readily by its brilliant black and yellow coloration. The head is depressed and nearly as broad as long; while the stout body is likewise somewhat depressed, without any crest along the middle of the back ; and the short 292 NEWTS AND SALAMANDERS. toes are devoid of any connecting webs. The smooth and shining skin is covered on the upper-parts with pores, from which exudes a viscid and acrid secretion, having decidedly poisonous properties. |The yellow markings on the head, back, and tail are arranged in two longitudinal series, broken up into more or less irregularly-shaped patches. The species is an inhabitant of Central and Southern 2) S . . . Europe, Algeria, and Syria; and is the one which from time immemorial has been dreaded, not only on account of its undoubtedly poisonous properties, but likewise owing to the extraordinary superstition that if thrown on a fire it would not be consumed. Frequenting moist and shady spots, either in the mountains among rocks, or in valleys and forests, the salamander passes the daytime in a kind of torpid condition, only issuing forth from its hiding-places among stones or roots of trees either during rainy weather or after nightfall; its skin being quickly dried up if exposed to the direct rays of the sun. Its movements on land are slow and sluggish, its gait being a crawl with a marked lateral movement ; but in water SPOTTED SALAMANDER (nat. size). the creature swims strongly, mainly by the aid of its tail. Although frequently found in the neighbourhood of its fellows, this salamander can searcely be termed a sociable creature; and it is only during the breeding-season that the two sexes live in company. From the slowness of its own movements, it is only slow- moving creatures such as snails, worms, and beetles that the salamander can capture for its food; although it is stated to occasionally kill small vertebrates. Generally a large quantity of food is consumed, after which there is a long fast, sometimes lasting for as much as a month. During the pairing-season, which is in April or May, both sexes betake themselves to the water, when the females collect the spawn deposited by the males. Although the young are usually born alive, it occasionally happens that egos are laid by the female, from which the young almost immediately make their escape. The number of tadpoles produced at a birth is very large, as many as fifty eggs being frequently found within the body of the female; while an instance is on record where upwards of forty-eight young were born within four-and-twenty hours. More generally, however, from SALAMANDERS,. 293 eight to sixteen, and less commonly from twenty-four to thirty tadpoles make their appearance into the world during a period of from two to five days. Generally all these are in an equally advanced state of development ; but sometimes in captivity both eggs and tadpoles are produced simultaneously, the former being translucent and showing the young tadpoles curled up within them. The tadpoles, which are generally produced in clear, running water, are blackish grey in colour. with a more or less well-marked greenish tinge; but there are small golden spots on the back, which gradually increase in size with advancing age. The skin also gradually becomes less shining and smooth, while at the same time the gills shrink, till about August or September the young salamanders quit the water for a terrestrial life. A few may, however, remain till as late as October. It is remarkable that the young salamander is rather inferior in size to the tadpole in ALPINE SALAMANDER (nat. size). the latest stage of development; and it is not yet known for how long a period it continues to grow after leaving the water. In aquaria salamanders develop more quickly, and have been known to leave the water within three weeks. The winter sleep generally takes place in moss-lined crannies, well protected from the frost, and may endure till the commencement of April. Alpine The Alpine, or black salamander (S. atra), inhabiting the Alps Salamander. at elevations of from three to ten thousand feet, is a smaller animal than the last, from which it may be at once distinguished by its inferior dimen- sions. Ranging from the Alps into Styria, Carinthia, and some of the mountains of Wiirtemberg and Bavaria, this species inhabits moist woods or the banks of mountain-streams, where it is generally found in small family-parties, which conceal themselves after the manner of their kind beneath stones and moss, or at the roots of the Alpine rose. Although resembling the spotted salamander in 294 NEWTS AND SALAMANDERS. producing living young, this species differs in that never more than two are born at a time. The most remarkable circumstance connected with the repro- duction of the species is, however, that from thirty to forty eggs are found in the oviducts of the females, out of which only one develops in each oviduct, at the cost of the remainder, which form a glutinous mass surrounding the develop- ing egg, and in which the liberated tadpole can afterwards freely move. ‘There are also some fifteen unimpregnated eggs in each oviduct, which serve as the food of the newly-hatched tadpole. The tadpole, which does not attain its full size till after birth, lies in the oviduct of the female with its tail curled, but is capable of moving and even turning round. Its gills are of unusual length, being nearly half as long as the whole body ; but before birth these shrivel up and are repre- sented by mere knobs, so that the whole of the tadpole stage is passed through within the maternal body. Tadpoles that have been taken from the oviduct before completing their development will, however, live in water like those of the other species; thus proving that the species originally went through a temporary aquatic existence. Although the two young salamanders are generally born at the same time, occasionally one develops more rapidly than the other, so that there may be an interval of several days between the births of the two. At the pairing-seasons these salamanders enter the water for a few hours, but are other- wise purely terrestrial The third representative of the genus is the Caucasian salamander (S. caweasica), distinguished from both the others by the tail being longer than the head and body. In colour this species is black, with irregular rows of round yellow spots down the back. Spanish This species (Chioglossa lusitanica) is the sole representative ‘Salamander. of a genus distinguished from the last by the tongue being supported on a median protrusile pedicle, and consequently free everywhere except on the front half of the median line. Considerably smaller than the spotted salamander, this species is dark brown in colour, rather lighter above than below, with two broad reddish golden bands along the body, separated from one another by a dark line along the middle of the back. It inhabits the north-western districts of Spain and the whole of Portugal. The newts (genus Molge) form an extensive group, of aquatic habits, spread over Europe, Northern Asia, and North America, and are the only members of the order found within the limits of the British Islands. Having the same number of toes as the salamanders, they are distinguished by the highly compressed and rudderike tail, as well as by the frequent presence of a fin-like crest down the middle of the back, which often attains a special development in the males during the breeding-season. With the exception of the crested newt, the skull differs from that of the salamanders by the presence of a ligamentous or bony arch connecting the frontal with the squamosal bone; and the palatine teeth form two nearly straight or slightly curved series. The tongue is free along the sides, but may be either attached or more or less free behind. The genus may be divided into two main groups, according to the presence or absence of a crest down the middle of the back of the males; and each of these may be further subdivided according to the characters of the so-called fronto-squamosal arch. Newts. NE WTS. 295 Belonging to the group in which the males are provided with a dorsal crest, this species (JV. cristata) differs from all the others in the absence of a fronto-squamosal arch to the skull; while it is further character- ised by the serration of the crest, and the orange and black-spotted coloration of the under-parts. The total length varies from 5 to 52 inches, and the toes of both limbs are free. The colour of the upper-parts is brown, blackish, or olive, with more or less distinct black spots; the sides are white-spotted ; and the under-parts Crested Newt. MALE AND FEMALE OF MARBLED NEWT (uat. size). orange, with black spots or marblings. During the breeding-season the head of the male is marbled with black and white, and there is a silvery band along the sides of the tail; while in the female the under surface of the tail is uniformly orange. The toes are yellow with black rings. An inhabitant of Britain, this species is spread over the greater part of Europe, extending as far north as Sweden, but unknown in Italy, and ranging eastwards to Greece, Turkey, and Russia. Not improbably Blasius’s newt (JZ. blasiz), from North-Western France, is a hybrid between the present and the next species, having the form and coloration of the former, but the fronto-squamosal arch of the latter. 296 NEWTS AND SALAMANDERS. Of the other European species, one of the handsomest is the marbled newt (M. marmorata), from France, Spain, and Portugal, of which a male and female are represented in the illustration on p. 295, Having a ligamentous fronto-squamosal arch to the skull, this species is specially dis- tinguished by the smooth dorsal crest of the male, and by the under-parts being generally dark with white dots. The total length is about five and a quarter inches. In general colour the upper-parts are green with black marblings; the crest of the male being ornamented with black and white vertical bars, while in the female an orange streak runs down the middle of the back. The sides of the tail have a silvery white band, most distinctly marked in the male during the breeding-season ; the under-parts are brown or greyish, with more or less distinct darker spots, and dotted with white; and the green toes are marked with black rings. Rare in France, this species is common in Spain and Portugal; and it lives in ponds and streams only in the early spring, spending the remainder of the year on Marbled Newt. dry land. The next species for notice is the Alpine newt Cll. alpestris), represented in the illustration on p. 289, which differs from the last by the much lower dorsal crest of the males, and likewise by the uniformly orange colour of the under-parts. In size it is a comparatively small species, varying from three and a quarter to four inches in length. In colour the upper-parts, which may be either uniform or with darker marblings, vary from brown, greyish, to purplish ; the sides have a series of small black spots on a whitish ground, beneath which, in the male during the breeding-season runs a sky-blue band; the crest on the back and tail is white with round black spots; the throat is frequently dotted with black ; the under-parts are uniform orange or red; and the lower edge of the tail of the female is orange spotted with black. The Alpine newt inhabits France, Belgium, Holland, Germany, Switzerland, Austria, and the north of Italy. A fourth European representative of the genus is the small common newt (MV. vulgaris), which belongs to the same group as the preceding, and is distinguished by the festooning of the dorsal crest, the lobate hind-toes of the male, and the black-spotted under-parts. Abundant in almost every English pond and ditch, where the water is sufficiently clear, this species ranges all over Europe, with the exception of the south of France, Spain, and Portugal, and is likewise widely distributed in temperate Asia. It measures about three and a quarter inches in length, and has a nearly smooth skin. The upper-parts are brown or olive in colour, with darker spots, larger and more.rounded in the male than in the female; the head is marked with five longitudinal dark streaks; the under- parts are yellowish, with a median orange or reddish zone, and marked with black spots in the male, and dots of the same in the female. In the latter the lower edge of the tail is uniformly orange, whereas in the male it is red, bordered with blue and interrupted by vertical black bars. Alpine Newt. Common Newt. The last of the European species we can notice at length is the webbed newt (MV. palmata), distinguished from all the preceding by the bony fronto-squamosal arch to the skull, and likewise by the webbed hind-toes of the male. This is the smallest species yet noticed, its length not exceeding three inches. The colour of the upper-parts is brown or olive, with small dark spots on Webbed Newt. NEWTS. 297 the body and longitudinal streaks on the head. In the male there are also minute brown speckles on the head; and the dorsal, as well as the upper part of the caudal crest, together with the hind-feet, are blackish. Except for a median orange zone, the under surface is uncoloured, although there may be a few small blackish dots ; there are a series of spots along the upper and lower borders of the tail, and the erest on its lower surface is orange in the female and bluish grey in the male, The webbed newt has been recorded from Britain, France, Belgium, Holland, Switzerland, Western Germany, and the north of Spain. With the exception of the banded newt (J. vittata) of Asia Minor and Syria, distinguished by the presence of a black band along each side of the body, all the other members of the genus are devoid of a crest along the back in the male. One of the most remarkable of these is Waltli’s newt Other Species. MALE AND FEMALE OF COMMON NEWT (nat. size). (CM. waltlii), from Spain, Portugal, and Tangiers, distinguished by the elongation of the ribs, which in some instances actually perforate the skin, so as to form a row of sharp points on each side of the body. In a fossil state the genus has been recorded from the lower Miocene paper-coal deposits near Bonn. Since the general habits of all newts are very similar, one account will serve for the entire group; but it must be remembered that whereas the whole of them are aquatic during the breeding-season, at the close of that period some species leave the water and live for the rest of the summer on land; while nearly all seem to pass some portion of the year out of the water. Newts generally prefer clear and running water, with plenty of aquatic plants on which to deposit their eggs. On land they are somewhat awkward and slow, but in water they swim with great rapidity by the aid of their oar-like tails, their hind-legs being pressed close to the sides of the body; their mode of progression Habits. 298 NEWTS AND SALAMANDERS. being thus exactly the opposite to that of a frog. They often stand upright in the water when coming to the surface to breathe, after which they will sink to the bottom with a snake-like movement in search of prey. When on land, they seek shelter beneath stones and roots, or in holes in the ground, and in such situations often undergo their winter sleep, although such as live in deep water pass the cold season of the year in a kind of torpor at the bottom, All newts are carnivorous or insectivorous, and the crested newt feeds largely on the tadpoles of the common frog, while the larger species will prey on the smaller members of their own genus. Although there is considerable difference in the spawning-time of the various species, the eggs are generally deposited during May or June, the female laying each egg Shall on the edge of the leaf of some water-plant, which is folded together by her hind-feet, and thus held by the viscosity of the egg. In the course a a few days after its deposition, the white embryo assumes an elongated form within the egg ; and soon it is seen to be folded upon itself, with the gills well developed, and in advance of them a pair of lobes by which the liberated tadpole affixes itself to aquatic plants. When about a quarter of an inch in length, and while the gills are still simple, the tadpole bursts its envelope; the front-limbs being represented merely by a pair of small knobs behind the gills. When hatched, it swims about in an aimless kind of way till it strikes against some object to which it can easily attach itself, and after a short time starts on another voyage. Development now proceeds apace, and in the course of two or three weeks the tadpole will have attained a length of about half an inch, while the gills will have become elegantly branched, and the fore-limbs well developed. At this period the eyes assume their permanent character, and the mouth has become terminal, while the lobes for attachment to plants are well-nigh absorbed. Still later the front feet, which had previously been only digitated, acquire four distinct toes, and the hind-limbs make their appearance and gradually assume their full proportions; but the gills have become still more complex. From this date the latter appendages gradually diminish in size, and shrivel, while the lungs are at the same time developed, until finally, about the latter part of the autumn, the creature has completed its meta- morphosis, and passed from the condition of a fish to that of a reptile. Although in most cases newts shed their skin piecemeal, in the crested newt it has been observed to be cast entire. Spectacled The presence of only four toes to each foot, and of a bony fronto- Salamander. squamosal arch to the skull, are the most distinctive features of the little spectacled salamander (Salamandrina perspicillata) of Italy, the sole repre- sentative of the genus to which it belongs. It is, however, further distinguished by its slender Saye and also by its somewhat compressed and rapidly tapering tail, furnished both above and below with a longitudinal keel, as well as by the palatine teeth being arranged in two parallel series diverging posteriorly. The tongue is very similar to that of the genus Chioglossa. Reaching from rather more than 3 to nearly 4 inches in length, this pretty little salamander has a warty skin, and is generally black on the upper -parts, although there is a triangular or chevron- shaped yellow mark on the top of the head. Beneath, the chin is white, the throat black, and the rest of the under-parts white, usually marked with black spots; the lower surface of the tail and adjacent part of the body is, however, bright carmine. AXOLOTLS. 299 The tarantolina, as this salamander is termed in Italy and Sardinia, inhabits cool, shady spots on the flanks of the mountains, where it feeds chiefly upon ants and spiders, and is active at all seasons of the year, having been seen abroad even in January. Although it appears that the pairing takes place on land, the females resort to the water in March to deposit their eggs, those that are the first to arrive taking the best places, such as sheltered corners of rock, where the spawn will be less likely to be washed away by floods. The young are hatched in about three weeks, and generally leave the water in June. In its movements on land this salamander is as active as a lizard. There are two other existing genera of the subfamily under consideration, both differimg from the preceding forms in that the maxilla or upper jawbone is more or less fully in contact with the pterygoid bone. Both have a fronto-squamosal arch, but whereas in Tylotriton this is bony throughout, it is ligamentous posteriorly in Pachytriton, which has also the tail Other Genera. SPECTACLED SALAMANDER (nat. Size). cylindrical at the base, instead of compressed throughout. ‘The former genus, in which the skin is extremely warty, is represented by one species from Siam and the Eastern Himalaya, and a second from the Liu Kiu Islands, while the latter is known only by a single Chinese form. Although properly speaking the term axolotl applies only to the permanent larval form of the Mexican representative of the genus Amblystoma, it will be found convenient in practice to make it include all the members of that group, whether mature or immature. Together with certain other genera, Amblystoma constitutes a second subfamily (Amblystomatine) distinguished from the Sulamandrinw by the teeth on the palate forming a transverse or posteriorly converging series, and being inserted on the hinder Axolotls. portion of those bones known as the vomers; as well as by the bodies of the vertebra being cupped at each end. The type genus is specially characterised by the palatal teeth forming a nearly straight or angulated series, not separated by : space in the middle line; and likewise by the radiating folds of skin on the tongue, which are oval or nearly circular in form, with the sides completely and the front NEWTS AND SALAMANDERS. 300 partially free. There are five hind-toes, and the tail is more or less compressed. tepresented by a number of North American species, one of which ranges as far south as Mexico, the genus has also one Asiatic member, inhabiting the mountains of Siam, probably at a great elevation. The majority of axolotls pass from the tadpole to the salamander stage in the ordinary way, but this is not the case with the Mexican race ot the Mexican axolotl (A. tigrinuwm), which likewise extends over a large area in the United States. The adult form is shown in our second illustration ; and in this condition the head is large and depressed, and has a broad and blunt muzzle, the limbs being stout, with short toes, and the rather long tail distinctly compressed, and LARVAL STAGE OF MEXICAN AXOLOTL (2 nat. size). keeled above and below near the extremity. The shining skin is finely granulated, and the general colour brown or blackish, with more or less numerous yellow spots, which may be arranged in transverse bands. In the United States, we believe, the transformation from the larva to the adult goes on in the ordinary manner; but the case is very different in Mexico. The city bearin is, as our readers are doubtless aware, surrounded by an extensive lake; while the country itself is characterised by its extreme dryness. In this lake dwell the creatures represented in our first illustration, which are known to the natives by the name of axolotl It will be seen from this figure that they resemble the tadpole stage of ordinary salamanders and newts in having large branching gills, and a deep rudder-like tail; and the natural conclusion would be that o” that name fo) AXOLOTLS. 301 they are larval forms. However, in the Mexican lakes, the axolotls remain permanently in the water, retaining their gills throughout life, and laying eggs, as if they were adult; and it was consequently long considered that they belonged to a type with persistent gills. It was not, indeed, until the year 1865, that light was thrown on the history of these remarkable creatures by six examples which had been living for more than a year at Paris. These comprised five males and one female, and in the middle of February the latter began to lay eggs, which in the course of a month hatched into tadpoles like their parents. In the following September the gills and crest of the tail of one of these began to shrivel, while the head increased in size, and yellow spots made their appearance upon the dark skin. Towards the end of the same month, and in the early part of October, similar changes took place in the others, and soon afterwards the whole four assumed the ADULT OF MEXICAN AXOLOTL (# nat. size). appearance of the salamander, which had been previously described as Amblystoma tigrinum. Subsequently experiments were made with other young axolotls by placing them in a glass vessel filled with water, but with rocks at one end, so that the creatures could creep out and expose themselves to the air as much as they pleased. After a day’s interval the amount of water in the vessel was diminished ; and almost immediately the gills of the axolotls began to shrink, and in the course of time, during which they dwelt chiefly im damp moss, the creatures eradually developed into air-breathing salamanders. It has been inferred from these remarkable experiments that the Mexican axolotl, like the other members of the genus to which it belongs, originally went through the normal series of trans- formations; but that, owing to the dry nature of the country it inhabits, it has acquired the habit of retaining the larval condition permanently. From its being able to breed in this state, it may further be inferred that the tadpole stage was 302 NEWTS AND SALAMANDERS. originally the permanent condition of all members of the order, and that the salamander stage is a later development. There are six other genera, belonging to the subfamily Ambly- stomatine, of which Hypnobius is represented by several Japanese species. Salamandrella, distinguished by having only four hind-toes, is a Siberian type, with two species ; Onychodactylus, which may be recognised by its black claws, is known by one species from Japan; while Ranidens, from Eastern Siberia and North-Eastern China, Batrachyperus from Moupin in Tibet, and the Californian Dicamptodon, all of which have the palatal teeth arranged in two arches, with their convexity forwards, and separated by a wide space in the middle, are likewise respectively represented by a single species. The two remaining subfamilies, which are exclusively American, can receive only very brief notice. In the first of these (Plethodontine) the series of palatal teeth is trans- verse and situated on the hinder part of the vomers; while there are also teeth on the parasphenoid bone; the bodies of the vertebrae being cupped at both ends. Of the five genera, Plethodon, with the tongue attached along the middle line to the anterior margin, and five hind-toes, is North American, where it is represented by several species. On the other hand, the large genus Spelerpes, which has the tongue attached only by a central pedicle, and all its edges free, ranges into Central America and the West Indies. The fourth subfamily, Desmognathine, differing from the last by the bodies of the vertebree being cupped behind and convex in front, is represented only by Desmognathus from North America generally, and Thorius with one Mexican species. Other Genera. THE FisH-LIKE SALAMANDERS. Family AMPHIUMIDA. The members of this family, which, for want of a better name, may be collectively designated by a translation of their German title, fischmolche, differ from the Salamandride in the absence of eyelids. The bodies of their vertebree are always cupped at both ends. They are all characterised by the weakness of the limbs in comparison to the body, and the wide separation of the front from the hinder pair. They live chiefly or entirely in the water, and breathe by means both of lungs and internal gills in the adult state. Only three genera are known, the first two of which are so closely allied that it is question whether they are really entitled to rank as distinct. Giant The earliest record that we have of this family is a skeleton Salamander. from the upper Miocene of Oeningen in Basle, described by Scheuchzer in the year 1726, under the name of homo diluvii testis; the learned doctor believing that he had to do with a human skeleton, which, like all fossils at that time, was considered to have been buried by the Noachian deluge. This fossil species, which was fully as large as the existing giant salamander, together with a smaller extinct species from lower Miocene strata near Bonn, probably belong to the same genus. The giant salamander (Megalobatrachus maximus) was first dis- covered in 1820 by Siebold in the rivers of Japan, but has been subsequently FISH- LIKE SALAMANDERS. 303 obtained from China. As a genus, it is characterised by having four front and five hind-toes, the absence of a gill-opening, and the presence of two internal gill-arches. MA) eh, iy p RH ‘ Ae og ; ane Le war Min Gg, : GIANT SALAMANDER (4 nat, size). The tongue covers the whole of the floor of the mouth, to which it is completely adherent ; while the palate has a curved series of teeth on the vomers, parallel to 304 NEWTS AND SALAMANDERS. 0 those on the margin of the upper jaw. In form the giant salamander is very stoutly built; the head being very large, wide, and flattened, with the muzzle regularly rounded, the small nostrils situated near the extremity, and the eyes very minute. The body is likewise broad and depressed; the legs and toes are short, the outer ones, as well as the outer side of the hind-leg, having a mem- branous fringe; and the short tail is strongly compressed, with a fin above and below, and its tip rounded. The skin, which forms a thick fold along each side of the body, is very warty, especially on the head; and the general colour is brown with black spots, becoming lighter on the upper-parts. Although the ordinary length of this salamander is about 35 inches, it is stated at times to grow to as much as 44 inches. Originally purchased by Siebold in the market of Nippon, the giant salamander is now ascertained to inhabit not only the mountain streams of that island, but likewise those of several parts of the Japanese mainland, as well as of Western Central China. Nowhere very abundant, the creature generally frequents the upper courses of small mountain-streams at elevations of from seven hundred to tive thousand feet above the sea-level; some of these streams being not more than a foot in width, and completely covered over with grasses and other herbage. The water is clear; and usually while the full-grown salamanders curl them- selves round masses of rock in the bed of the stream, the younger ones live in holes. Except in search of food, which consists of worms, crustaceans, fish, and frogs, the animals do not leave their hiding-places, and then only at night, while they never venture on land. In confinement they are extremely slow and sluggish in their movements, only exhibiting any marked activity when they rise to snap at a worm or other tempting morsel. In spite of its large size, the female lays very minute eggs, which are generally deposited in August and September. The smallest young yet observed had a length of about 6 inches, and in every respect resembled the adult. Probably however, at an earlier stage of development, external gills were present ; and indeed, in an illustrated Japanese book, the young of the giant salamander is represented with these appendages. Further evidence of this is afforded by the circumstance that young specimens have been taken in which the gill-openings were retained. The first two living examples were brought to Europe in 1829 by Siebold, and were fed on fresh-water fish brought from Japan, but when these began to fail, the male devoured his unfortunate partner. When suitable food was procured, the male, however, flourished and increased rapidly in size, surviving till the year 1881, when it died in Amsterdam. Under this euphonious name is designated in its native country the Mississippi salamander (Cryptobranchus lateralis), which differs from its Asiatic cousin by the presence of a gill-opening, at least on the left side of the neck, and likewise by the presence of four pairs of gill-arches, and by the Hell-Bender. anterior border of the tongue being free. In general form this salamander closely resembles its larger relative; the skin being porous and rather smooth, and the head covered with scattered wart-like tubercles. The colour is brown or greyish, with darker blotches; but the tips of the toes are yellowish. In length this species, which is the sole representative of its genus, reaches about 16 or 17 inches ; and it inhabits all the tributaries of the Mississippi, and ranges into North Carolina. FISH-LIKE SALAMANDERS. 305 In these streams it crawls or swims in a sluggish manner, seldom leaving the water, although it can exist on land for twenty-four hours or so at a stretch, feeding on crustaceans, worms, and fish, and being not unfrequently taken on the angler’s hook. From the circumstance that the tadpoles have never been observed, it would seem that the larval stage must be of very short duration; and the only thing known about the development of the species is that the eggs are of relatively large size. Although perfectly innocuous, the hell-bender is regarded by American fishermen as a most noxious and poisonous reptile. It was first brought alive to Europe in 1869, since which date it has been frequently exhibited; and if fed on meat or the heads of fish will rapidly increase in size, although it appears to voluntarily undergo long fasts. While in the water it has been observed to ~<. *\ feed LUO HELL-BENDER, OR MISSISSIPPI SALAMANDER (4 nat. size). make the air from its lungs pass over the gills, with the apparent object of more fully oxygenating the blood in the latter. Three-Toed The eel-like or three-toed salamander (Amphiwma means) Salamander. yepresents another North American genus, ranging from the Mississippi to South Carolina, and distinguished by its extremely elongated and eel-like form, and the small size of the limbs, each of which terminates in three or two minute toes. The tongue is indistinctly defined, covering the whole of the floor of the mouth, to which it is everywhere adherent; there is a gill-aperture on each side of the neck, and four internal gill-arches are present. The head is relatively small, with a rather long and narrowing muzzle, at the extremity of which are the small and widely- separated nostrils; the eyes are likewise minute; the lips are unusually thick and fleshy ; and the short compressed tail is keeled superiorly. The smooth and slimy VOL. V.—20 306 NEWTS AND SALAMANDERS. re) skin is of a uniform blackish brown colour, although rather lighter below than above. In total length, full-grown examples measure about 31 inches. From the difference in the number of the toes it has been thought that there are two species ; but since the two-toed and three-toed forms are in other respects similar, 1t seems preferable to regard them as varieties or local races of a single species. These salamanders are inhabitants of muddy waters, frequently burying themselves in the mud at the bottom, in one instance to the depth of a yard or more, in thick clayey mud of the consistence of putty, in which they burrowed like worms. They also frequent the irrigation channels in rice-fields, while they occasionally venture THREE-TOED OR EEL-LIKE SALAMANDER (4 nat. size). on land. Their food comprises fresh-water mussels, fish, beetles, other insects, and crustaceans. Beyond the fact that the female lays eggs, in which the tadpole lies coiled up until it attains several times the length of its chamber, little is known as to the breeding-habits of this species. THE GILLED SALAMANDERS. Family PROTEIDZ. Represented only by the curious olm of the subterranean waters of Carniola and other parts of Europe, and by an allied genus in North America, the gilled salamanders take their title from the permanent retention of external gills, on which account they may be regarded as some of the lowest representatives of the GILLED SALAMANDERS. 307 order. In addition to this primary feature, they are characterised by the absence of the upper jawbone or maxilla, although the premaxilla is present, and, like the lower jaw, furnished with teeth. There are no eyelids, and the bodies of the vertebrae are cupped at both extremities. There are differences in the external form of the two representatives; the olm being a long, snake-like creature with small limbs, whereas the American species resembles a salamander. Known for more than a couple of centuries, the remarkable creature to which Oken gave the name of olm is the sole representa- tive of its genus, and is technically known as Proteus anguineus. From its American ally it is distinguished by its elongated snake-like body and small and widely Olm. THE OLM (2 nat. size). separated limbs, of which the front pair are provided with three, and the hinder with only two toes. The eyes are concealed beneath the skin, the small tongue is free in front, and the palatal teeth are small and arranged in a double series. In the typical form from Carniola the head is elongate, with a long and narrow muzzle, truncated at the tip; the mouth being small, with large lips. The short and much compressed tail is provided with a fin, and rounded or bluntly pointed at the tip. The smooth skin is marked by twenty-six or twenty-seven grooves, corresponding to the ribs, and is uniformly flesh-coloured, with coral-red gills. In a variety from Dalmatia the snout is longer and narrower, and the number of costal grooves only twenty-four; while in a second variety, inhabiting Carinthia, the whole form is stouter, the head shorter, with a rounded muzzle, and the number of costal grooves twenty-five. There is also a certain variation as regards colour, apparently largely depending upon the amount of light to which the creatures have been exposed; some examples being reddish brown, and others darker with bluish black spots. The usual length is about 10 inches, 308 NEWTS AND SALAMANDERS. Totally blind, the olm is found solely in the subterranean waters of the caverns of the Alps of Carniola, Dalmatia, and Carinthia; and has long been an object of the greatest interest to naturalists. It has been thought that the waters in which the olm lives were all connected together underground, and that the creatures only came up during flood-time ; but the great distance from one another of the various localities where they are found is somewhat against this view. It is, however, only when the subterranean waters are at their greatest height that the olms are captured by the peasants, by whom they are placed in glass jars, half filled with water and sold to tourists. In confinement, where they have been known to survive from six to eight years, they lie sluggishly all day at the bottom of their tank, only moving if a ray of light impels them to seek a darker corner. When in small vessels, where the water is not often renewed, they will frequently come to the surface to breathe, opening their mouths, and letting air pass through their gill-openings; but in deeper, or frequently changed water, they breathe entirely by means of their gills) Many experiments have been made, with the view of ascertaining whether the olm will, under any circumstances, lose its gills, but hitherto without result. In captivity the food of these amphibians consists of molluses, worms, and the minute creatures to be found among the leaves of water- plants. In spite of having been kept for many years in captivity, it was not ascertained till 1875 that the olm lays eggs; and it was thirteen years later before any tadpoles were hatched in captivity. In April 1888, upwards of seventy-six egos were laid by a single female; and after a period of three months developed into tadpoles, These were very similar to the adult, but the tail-fin extended three-quarters down the back ; the eye was larger, and apparently more susceptible to light ; and the hind-limbs were in the form of small knobs. Furrowed A very. different looking animal is the furrowed salamander Salamander. (Necturus maculatus), of Eastern North America and Canada, which takes its name from the strongly-marked fold of skin on the throat. In addition to its shorter and more lizard-like form, and relatively longer limbs, it differs from the olm by having well-developed eyes, and four toes to each foot. The tongue is large, with the front border free; and the palatal teeth are large and form a single series. In colour the smooth skin is brown, with more or less well-defined circular blackish spots, and lighter on the under-parts than on the back. The total length is about a foot. An allied species (WV. punctatus) inhabits the rice- fields of the Southern States. The food is similar to that of the allied forms, and in winter these salamanders seek protection from frost by burrowing deep in the mud. They come at times to the surface to breathe, and will even venture on land ; but they chiefly respire by means of their gills, and if the latter become entangled, they are carefully rearranged by means of the fore-foot. Two-LEGGED SALAMANDERS. Family SZRENID. The sole representatives of this, the last, family of the Tailed Amphibians are the two-legged salamanders of North America, of which there are two species, arranged under as many genera (Siren and Pseudobranchus). While agreeing TWO-LEGGED SALAMANDERS. 309 with the preceding family in the permanent retention of external gills, they are distinguished by the total loss of the hind-limbs, and likewise by the absence of teeth in the margins of the jaws. The siren salamander (Siren lacertina), which inhabits the South-Eastern United States, may be compared to a snake furnished with a pair of short fore-legs and external gills; and is especially distinguished by the presence of three pairs of gill-openings on the sides of the neck and the four-toed feet. The smooth skin is either uniformly blackish, or marked with small white dots, and the total length reaches to as much as 28 inches. The Georgian two-legged salamander (Pseu- dobranchus striatus), on the other hand, has only a single pair of gill- openings on the neck, and but three toes to the feet. These salamanders are stated to frequent swampy localities, especially pools of : : water beneath the roots of old SIREN SALAMANDER. trees, up the stems of which they will sometimes climb. A living example was received in England in 1825, where it lived till 1831. This specimen was fond of coming out of the water to rest on sand or among moss; and in summer ate worms, tadpoles, and various other small creatures, but became torpid from the middle of October till the end of April. That these salamanders can breathe entirely by means of their lungs, is proved by a specimen in an aquarium whose gills had been eaten off by a fish. THE CC@cCILIANS OR WoRM-LIKE AMPHIBIANS. Order APODA. The remarkable worm-like and blind amphibians forming this group are generally regarded as the representatives of a distinct order; although they are considered by Professor Cope to be merely a degraded branch ae the Tailed Amphibians, to which they are allied through the fish-like salamanders. Be this as it may, the group is readily distinguished by the total absence of limbs, and the general worm-like appearance of the head and body; the tail being either rudimental or wanting. In the skull the frontal bones are distinct from the parietals, but the palatines are fused with the maxilla. As regards their reproduction, these amphibians differ from the newts and salamanders in that the two sexes come together in the ordinary manner. Some of them are peculiar in having overlapping scales embedded in the skin, like fishes; and in all the eyes are either wanting, or are so deeply buried beneath the skin as to be entirely 310 NEWTS AND SALAMANDERS. useless. The whole of the members of the group are burrowing in their habits; and in the aduit state are completely terrestrial, laying eggs from which are developed gilled tadpoles that do not take to the water till some time after birth. The fourteen genera into which the group has been divided may all be included in the single family Cwciliidw. Geographically, these amphibians are spread over the Indian region, Africa south of the Sahara, and Central and South America ; but it is not a little remarkable that they are quite unknown in Madagascar, although two species occur in the Seychelles. They may be divided into two main groups, from the presence or absence of scales in the skin; two of the best known representatives of the group in which scales are developed, at least in some portion of the body, being the Oriental Ichthyophis and the South American Cwcilia; one of the species of the latter genus being represented in our illustration. The common Cingalese species (Ichthyophis glutinosus), which ranges from Ceylon and the Eastern Himalaya to MA ci UL) A WORM-LIKE AMPHIBIAN, Cecilia (nat, size). Sumatra and Java, inhabits damp situations, and usually burrows in soft mud. In some hollow near the water, the female (which measures about 15 inches in length), lays a cluster of very large eggs, round which she coils her body, and proceeds to brood them after the manner of a python. After the young are hatched out they remain in the egg-moss until they have lost their external gills, after which they take to the water, to lead for a time an aquatic life. During this stage of their existence the head is fish-like, with large lips, and the eyes better developed than in the adult; and they have a gill-opening on each side of the neck, and the tail is distinctly defined, much compressed, and furnished both above and below with fin. Of the group without scales, the genus Gegenophis is from Southern India, Siphonops from Tropical America, and J'yphlonectes and Chthoner- petum from South America. SKELETONS OF PRIMEVAL SALAMANDERS. Protriton, A, and Pelosaurus, B. (From Credner ; much enlarged.) CE AvP Bika olelale THE PRIMEVAL SALAMANDERS,—Order LABYRINTHODONTIA. THE remaining amphibians are extinct, and form an order mainly characteristic of the upper Paleozoic and Triassic periods, but also lingering on into the Jurassic. They derive their name of Labyrinthodonts from the complex structure of the teeth of the higher forms; these displaying a peculiar pattern, caused by infoldings of the outer layer, which penetrate nearly to the centre of the crown in festooned lines. Most of these creatures have the general form of a salamander, with the front-limbs shorter than the hinder-pair; the latter having always five toes, although in the former the number may be reduced to two. Their most characteristic feature is, however, to be found in the structure of the skull, in which the bones are generally covered with a pitted or radiated sculpture, somewhat similar to that of crocodiles. From the accompanying figure of the skull of the mastodonsaur, it will be seen that the whole of the upper surface behind the sockets of the eyes is covered by a complete bony roof, extending continuously from the bone marked P, which immediately covers the brain-cavity to the sides of the hinder-part of the jaws (QJ), whereas in all the modern salamanders this region is more or less open. This roofed skull of the primeval salamanders presents an approximation to the earlier fishes; and a resemblance to that group is also shown by the paired supraoccipital bones (So), 312 PRIMEVAL SALAMANDERS. which in all the higher Vertebrates are fused together. Nearly all these salamanders are further distinguished by having the chest protected by three sculptured bony plates, one of which is central while the other two are lateral; the position of these plates being shown in our figure of the skeleton, where they are seen on the lower surface of the body, immediately behind the head, under- lying the backbone and ribs. Besides this armour, some species had the whole of the under surface of the body protected by a series of bony scales, arranged in a chevron pattern; while in a few instances similar scales also invested the upper surface of the body. The majority of the members of the order had the vertebrae of the backbone in the form of simple doubly-cupped discs, similar to those of fishes; but in some of the most primitive types each vertebra consists of four distinct pieces, SKULL OF THE MasToponsauR, wira THe MAmMely, a single basal piece (2), a’ pair of lateral SCULPTURE OMITTED. pieces ( pl), and a single arch and spine (s). Among SO, supraoccipital; Ep, epiotic; Pp, Some reptiles the basal piece remains between parietal; Sg, squamosal; ST, supratem- two adjacent vertebree as the intercentrum; but poral; QJ, quadratojugal; Ju, jugal; Pt, . A postfrontal ; P40, postorbital; F’r, frontal; 1 the higher forms the other elements coalesce. Pri, prefrontal; L, lachrymal; Wa, nasal; Since a similar type of vertebra occurs in certain Mz, maxilla. The premaxilla has no letter. : : ° (About 4 nat, size.) extinct fishes, we have in this structure another bond between the latter and the primeval sala- manders. Brief reference must also be made to the small aperture in the roof of the skull of the primeval salamanders in the bone marked P, since this corre- sponds to one in the skull of the tuatera lizard of New Zealand. In that animal the aperture overlies the rudiment of an eye sunk deep down in the brain and now totally useless, but probably functional in the tuatera’s ancestors. The large size of the aperture in the primeval salamanders suggests that the central eye may still have been capable of receiving impressions of light, although we may have to go back to earlier forms before it was of any functional importance as an organ of vision. As in many existing amphibians, teeth frequently occur on the bones of the palate as well as in the margins of the jaws. Another feature y : TWO VERTEBR® OF A PRIMEVAL SALAMANDER. of the skulls of many members of the order pra is the anterior and pétz the posterior end. is the presence of what are called mucous canals in the bones of the upper surface, as shown both in the accompanying figure and in the one on p. 313; these canals also occurring in certain fishes. So far as can be ascertained, both external and internal gills generally disappeared in PRIMEVAL SALAMANDERS. 202 the adult. Varying from the size of a small newt to that of a crocodile, the primeval salamanders are of especial interest to the evolutionist, as it is pretty certain that not only are they the descendants of primeval fishes, but that they are the ancestors both of the modern Amphibians and the extinct Anomodont Reptiles. And it is probable that Mammals have originated, either directly from them or from a lost group intermediate between them and the Anomodont Reptiles. They appear to have been spread over the whole globe, and they have been divided into several subordinal groups. Among these the highest are the true Labyrinthodonts, : NLL s typically represented by the gigantic Mastodonsaurus \We>" $8, begs AS and the somewhat smaller Metoposawrus of the Trias, \Ao> >=! Vas These were crocodile-like animals, generally with dise-like vertebrze in the adult, the teeth more or less plicated, and the surface of the skull marked with sculpture and mucous canals, In the Permian Archegosawrus, the vertebre were, however, of the complex primitive type. The Gilled Labyrinthodonts, ~ as represented by Protriton and Pelosawrus, are a group of much smaller forms. characterised by their barrel-shaped vertebre, pierced by a remnant of the canal of the primitive notochord; short and straight ribs, articulating by a single head; simple teeth, and eecrty Ob Man Muciononate the absence of ossification in the occipital region of (} nat. size). the skull, as well as in the wrist and ankle-joints; a further point of distinction being the development of internal gills in the young. The Permian and Carboniferous Snake-like Labyrinthodonts are characterised by the snake-like form of the body, and the apparent absence of limbs. The vertebra were elongated and without spines, while the ribs were slender and barbed like those of fishes, and the teeth smooth and simple. Probably the external gills persisted throughout life. In Britain the group is represented by the small Dolichosoma; but Palcwosiren of Bohemia is estimated to have been over 40 feet long. If these creatures prove to be the ancestors of the Worm-like Amphibians, it would show that the latter are distinct from. the newts and salamanders. The Microsauria, include small lizard-like forms, such as Ceratoerpetum and Hylononus from the Carboniferous of Europe and Nova Scotia, which appear more highly organised than the preceding, and thus connect the Amphibians with the Beaked Reptiles. Their vertebre are long and constricted, with traces of the notochord ; the ribs are generally long, curved, and two-headed; the teeth have large central pulp-cavities, but no plications; the occiput is ossified ; but the wrist and ankle are either ossified or cartilaginous; and in some cases the back is covered with bony scales. In several forms the bony scales on the under surface are so slender as to assume the appearance of abdominal ribs like those of the Beaked Reptiles. PLS iiss, CHAP TE Ra GENERAL CHARACTERISTICS,—Class Pisces. ALTHOUGH in popular language lampreys are included among fishes, while until quite recently the lancelet was very generally placed by zoologists in the same class, it now seems preferable to make each of these the representative of a distinct class, and the true fishes can consequently be defined with greater precision. In this somewhat restricted sense fishes may be described as cold-blooded vertebrate animals, adapted for a purely aquatic life, and breathing almost invariably by means of gills alone. They have a heart consisting generally of only two chambers (three in the lung-fishes); the limbs, if present, are modified into fins; there are unpaired median fins, supported by fin-rays; and, as in all the higher classes, the mouth is furnished with distinct jaws. The skin may be either naked, or covered with scales or bony plates. As a rule, fishes lay eggs; and the young do not undergo a distinct metamorphosis. With the Tailed Amphibians the class is very closely connected by means of the lung-fishes, which are furnished not only with internal gills, but likewise with functional lungs, and during the early part of their existence with external gills; while these fishes also differ from the other members of the class in that the nostrils communicate posteriorly with the cavity of the mouth, as in the higher Vertebrates. GENERAL CHARACTERS. SES Although the bony fishes of the present day form a specialised side-branch, which has lost many of the characters common to the two classes, it will be evident that Fishes and Amphibians are very closely allied groups; the latter of which has been directly derived from the former. Geologically, fishes are older than any of the classes hitherto described, their fossil remains occurring in strata belonging to the upper part of the Silurian division of the Paleeozoic epoch. The form of a typical fish is so well known that it will be quite unnecessary to describe it; and it may be mentioned that this typical form, which is the one best adapted for progress through water, is very general amongst fresh-water fishes, although the eels constitute an exception in this respect. Much greater diversity exists, however, among the marine representatives of the class; and we may cite as extreme types a shark, a flat-fish, a ribbon-fish, and a globe-fish. The structure of the skeleton, both external and internal, being of the utmost importance in the classification of fishes, it is essential that the attention of the reader should be more fully directed to this point than has been done in the case of the higher Vertebrates. It should first be mentioned that fishes are divided into four subclasses, namely, the Lung-Fishes or Dipnoi ; the Chimeroids, or Holocephali; the Bony Fishes and Ganoids, or Teleostomi; and the Sharks and Rays, or Elasmobranchii. These may be further subdivided into orders as follows :— Classification. 1. Lung-Fishes—Subclass Drpnot. (1) True Lung-Fishes—Order SIRENOIDEI. (2) Berry-Boned Fishes—Order ARTHRODIRA (extinct). Chimeroids—Subclass HOLOCEPHALI. Bony-Fishes and Ganoids—Subclass TELEOSTOMI. (1) Fan-Finned Fishes—Order ACTINOPTERYGII. (2) Fringe-Finned Ganoids—Order CRossoPTERYGIL Sharks and Rays—Subclass ELASMOBRANCHIL. (1) Acanthodians—Order ACANTHODI! (extinct). (2) Fringe-Finned Sharks—Order IcHTHYOTOMI (extinct). (3) True Sharks and Rays—Order SELACHOIDEI. go po ca External In regard to the external skeleton, the most characteristic type Skeleton. takes the form of scales. When these overlap and their posterior border is entire, such scales are termed cycloid, but when serrated, ctenoid. The external skeleton may, however, take the form of plates or granules, which in the chimeroids and sharks and rays are generally isolated, and have a structure precisely similar to that of teeth, consisting of a base of ivory or dentine capped with enamel. The so-called ganoid scales, like those of the bony-pike, are, on the other hand, quadrangular, and often connected by a peg-and-socket arrangement ; they are formed of true bone capped with an enamel-like substance termed ganoin, and true bone likewise occurs in the plates of the sturgeons. A series of specially modified scales, running along the sides of many fishes, constitute the so-called lateral line, which is partly connected with the supply of mucus ; and certain large V-shaped scales on the borders of the fins of many extinct bony fishes are known as fulera. The fin-rays, which also come under the designation of dermal structures, FISHES. 316 ‘uy ofajed Jo sXvi 4yos puv pavy ‘a7 “yy f stayed “7 faymnorarpoysod Sy ‘7 {uy pesozoad jo shea ‘zy Y fspeseq Sy femndvos 7 { proovsoo ‘qf avqnoraryo ‘9 favqnoravpovadns “gq ‘ yeroduroy-ysod ‘py + uy yeue jo shut qos pue pavy ‘s “ fuy peur jo syeurdssoqur ‘D {sourds peuraysoyur ‘ug yepneo jo sXvx qos pue paey ‘o ‘w Suy [esiop azspury Jo skvx qos “w pue ‘prey “7 { Uy [esiop Jomeyue jo sXvr-uy “y { speurdszoyur Jorseysod “2 ‘ speutdsseyur Jolrozyue “y ! wiqoz1oa Jo soutds puv soyore domadus “ff sqit Jo sqreq f i sqit ‘a £ maqayIoA-[rey Jo sourds pue soyoue aorseyut “p { sosseooid osioasuesy ‘9 fwIqa}Ioa-yley JWoNyUod “7 f waqoytaa ‘y {(paywoouod) seky ‘ye favpnsuv “ge ¢ wwpMoyse “cg ‘ Kreyuap ‘pe { avjnosedossym ‘ee $ avpnosedoqns ‘Ze { oyootdurds ‘Tg f avpnoredoaad “og { (payweouod) [eAyorAys “GZ £ avpnosodo ‘gz, £ prosAroydeyour ‘7Z ‘ ayerpenb ‘9gz £ proSfraqydoyua ‘ez § proStaaydoyoo Fz f avpnqrpuemoty ‘ez {(pefesouos) ounryed ‘Zz { pesoduayeadns ‘Tz fyeseu ‘oz : Sarr yeyqiovayur “ET “eT ‘ euoqmel soddn 10 “epprxeut “QT $ vyxemard “yp §(gT £q weppry) aoutoa ‘gq { (pateeou0s) prousydsaad ‘eT £ prousydsoyqio “FT { pesouenbs ‘gy £ proysetu ‘Zp £ (payeeouos) proueydstye ‘TT éqeqidioo0xe “oT fpeydioooaed “g { peydrooovadns ‘g § eyorred ‘7 ¢ prouaydseaed ‘9 §(papeeouod) [eydrooorseq ‘¢ f TeyUoAysod ‘pf prowyya ‘g f peyuoajaad “Z : peyUody “T = “HOUdd AO NOLATANS » Sy ANN GENERAL CHARACTERS. 317 are shown in the skeleton represented on p. 316, and occur in both the median and paired fins, of which the names are also given in the same illustration. In the median fins the bases of these rays articulate with the wnterspinal bones, or, in elasmobranchs, with the radial cartilages. The first rays of the pectoral and dorsal fins may be developed into long spines, having the same structure as teeth. Internal In the internal skeleton the back- Skeleton. bone is divisible only into a trunk and caudal moiety. In the fringe-finned ganoid fishes the primitive notochord persists, although it may be partly surrounded by rudimental arches; while in the sharks and higher bony fishes the column is divided into segments, forming vertebrae with doubly-cupped bodies. In sharks and rays the arches and bodies of the vertebrae remain separate, but in the other groups they are fused together; in the tail, as shown in our figure of the skeleton of the perch, there is also an inferior arch and spine to each vertebra. In the more primitive fishes the notochord is continued to the hinder extremity of the body, where it is surrounded symmetrically by the rays of the caudal fin; this type, which is shown in the accompanying figure of the skeleton of an extinct fringe-finned shark, being termed the fringe-tarled, or diphycercal. Whereas in some fishes with this type of tail the fringes on the upper and lower portions of the caudal fin are of nearly equal depth, in others the lower fringe of rays becomes somewhat deeper than the others, and a further development of this inequality results in the partially forked or heterocercal tail of the modern LSS. LAELEL LA Vi PAE N ZZ 7 ZZ 5K \ \\ “JIVL IVOUAOAHdIG PDNIMOHS SHUVHS GANNIA-ADNIVA LONILXA dO NOLATANS sharks and sturgeons, where the end of the backbone is bent upwards into the longer superior lobe of the tail, the lower lobe of which is formed exclusively of rays. The lung-fishes and sharks have never advanced beyond one or other of these types; but (‘yospia Wo01,7) the bony fishes and ganoids, which started with the primitive fringed lobate type, by a gradual shortening of the central part of the tail-fin, accompanied by an increasing development of the rays on its lower side, have evolved the completely forked or homocercal tail of the perch, in which, as shown in the figure, the backbone stops short of the fin-rays, and ends in an expanded, unsymmetrical extremity, from which these rays are given off in a fan-like manner, so as to produce an appearance of perfect symmetry in the whole structure. Turning to the limbs, or paired fins, we find that while in the existing oD 318 FISHES. elasmobranchs there are no membrane-bones (as the elements of the skeleton not formed from primitive cartilage are termed), in the higher bony fishes the pectoral girdle, as shown in the figure on p. 316, comprises a scapula and a coracoid, flanked by a series of membrane-bones, known as the post-temporal, supra- G : Se S OO SS Ss SSS SS SSS Pre err SS wT EXHIBITING HETEROCERCAL TAIL. SKELETON OF STURGEON, clavicular, clavicular, and postclavicular. The pelvis is generally absent, and is never highly developed. In all cases the basal and radial bones of the pectoral fins articulate directly with the pectoral girdle, so that there are no segments corresponding to the arm and fore-arm of the higher Vertebrates. In the paired fins the struc- ture is very similar to that of the tail; and a similar transition from a fringed to a fan-like type may be traced as we pass from the primitive to the specialised forms. For instance, in the figure of the perch’s skeleton on p. 316, we may notice that the paired fins are formed of a number of hard rays spreading out in a fan-like manner from a single point of origin; and the same general type obtains in the existing sharks and rays. In certain extinct sharks, like the one of which the skeleton is shown on p. 317, as well as in the lung- fishes and the fringe-finned ganoids, the pectoral fins have a long central lobe running for some distance up the middle, and completely covered with scales (where these are developed), while the rays of these fins form a kind of fringe radiating on all sides from the central lobe. The skeleton of such a fin, which is known as an archipterygium, consists of a long cartilaginous axis, composed of a number of joints, gradually decreasing in size from the base to the extremity, as shown in the figure on p. 319. From one or both sides of such joints there are given off a number of oblique smaller jointed rods, terminating in the fine rays forming the free edges of the fins. How different is the structure of this fin from that of the higher bony fishes will be apparent by comparing the accompanying figure with that of the skeleton of the perch on p. 316. In the lung-fishes this primitive type of fin has persisted to the present day ; in the sharks it has now totally disappeared; while among the bony fishes and ganoids, in the latter of which it was the universal type at the period of the Old Red Sandstone, it now only remains in a modified form in the bichir of the Nile, having been developed in the modern bony fishes into the fan-type. It may be mentioned that the latter modification of fin is obviously the one best adapted for quick-swimming fishes, the fringe-finned type partaking more of the nature of clumsy paddles, and being adapted for slowly-moving forms like the lung-fishes, which pass most of their time among the mud at the bottom of rivers. GENERAL STRUCTURE. 319 It must not be supposed, however, that even the fringed type is the most primitive form of fin known, since in an extinct armoured shark (Cladoselache) from the Carboniferous formation, we meet with what may be called the fold-type of paired fins. In these fishes (one of which is figured in the sequel) the pectoral and pelvic fins are placed far apart, but in the same longitudinal line, and are formed of a series of parallel cartilaginous rods arising from an extended base, and projecting at right angles to the body; the pectoral pair being considerably the larger. Assuming that fishes originally possessed on each side of the body a continuous fold of skin, strengthened by parallel cartilaginous rods projecting at right angles, this fold-type is exactly what we should expect to find in the evolution of pectoral and pelvic fins, by the disappear- ance of a considerable portion of the original fold, and the development and basal contraction of the remaining moieties. Although the structure of the skull is of the highest importance in the classification of fishes, our remarks on this subject must be very brief. In the skulls of the higher bony fishes the original cartilaginous cranium, which persists in the sharks, is overlain by a number of membrane-bones, the names and position of which are indicated in the figure of the perch’s skeleton on p. 316. Among these the pterotic and sphenotic are peculiar to the class, and there is always a large para- sphenoid underlying the base of the skull. The inter- SKELETON OF PECTORAL FIN OF z : AN EXTINCT FRINGE-FINNED and symplectic between the squamosal and the quadrate is SHARK. (From Fritsch.) unknown elsewhere, although it is by no means universal among fishes. Among other bones may be mentioned the infraorbital ring beneath the eye; as well as the preopercular, subopercular, interopercular, and opercular, collectively constituting the gill-cover or operculum of the bony fishes. In the gill (or branchiostegal) membrane, which joins with the gill-cover in closing in the gill-chamber, there may be developed a number of gill (or branchiostegal) rays; but these may be partially or entirely replaced by jugular plates, occupying the space between the two branches of the lower jaw. It will be unnecessary to mention by name the various bones constituting the hyoid arch, which is attached to the inner side of the hyomandibular by the stylohyal, and extends forwards to support the tongue; and it will suffice to state that behind this arch are situated the branchial or gill-arches, to the inner margins of which are attached the spine-like gill-rakers. In the lower jaw, or mandible, there is usually both a dentary and an articular piece; but an angular, and more rarely a splenial or coronoid element may likewise be developed. The teeth of fishes present a greater degree of variation than is found among any other class of Vertebrates. While in some- cases they may be totally wanting, in others they may be developed on all the bones of the mouth, and even on the hyoid bones and gill-arches; and they may be attached only to the membrane lining the cavity of the mouth. Frequently vention of the elements known as the hyomandibular Teeth. 320 FISHES. they are welded to the underlying bone or cartilage by a broad basis; but, as in the saw-fishes, they may be emplanted in distinct sockets. Usually the coating of enamel is very thin; and the ivory, or dentine, is more vascular than in the other classes. In rare instances the ivory may be penetrated by branching prolongations from the central pulp-cavity, as well as by similar infoldings from the exterior, thus producing a structure similar to that obtaining in those of the primeval salamanders. As a general rule the teeth are being constantly renewed through- out life, but in a few instances a single set persists. In beauty, variety, and changeability, the colours of fishes cannot be exceeded by those of any of the other vertebrate classes ; metallic tints and almost all the colours of the rainbow being very commonly displayed; while the beauty of the coloration is often enhanced by the rapid changes it undergoes. In many cases the coloration is of a protective nature. An example of this is afforded by the colouring of the upper surface of many flat-fishes, such as flounders, which exactly harmonises with the tints of the sea- bottom on which they dwell; while another equally marked instance presents itself in the case of so-called pelagic fishes, ike the mackerels and flying-fish, which live near the surface of the sea, and have the under-parts silvery white, and the back mottled with dark green and black. When viewed from below against the light sky such a fish is practically invisible, while it is equally inconspicuous when seen from above among the dark waters. . The body of fishes is made up of a great lateral muscle on each side, divided into a number of segments corresponding with the vertebre, and also separated into a dorsal and ventral moiety by a median longitudinal groove. On its surface the lateral muscle is marked by a number of white zigzag stripes, generally forming three angles, of which the middle one is directed forwards; these stripes being formed by the edges of the tendinous divisions between the segments. Generally the muscles are glistening white in colour; but in some instances they are “salmon-coloured,” this tint being due to the colouring matter of the crustaceans on which such fish subsist, which is turned red by the action of the digestive fluids in the same manner as by boiling. The electric organs possessed by certain fishes are considered to be probably formed from specially developed muscles. With regard to the brain, it will suffice to say that it is of an exceedingly low type; and that the ear lacks the tympanum and tympanic cavity of the higher classes. In the bony fishes there occurs at the base of the brain-cavity a sac, often divided into two unequal-sized chambers, and sach of which contains an ear bone, or ofolith, of very dense structure. These otoliths, which are very constant in form in the different groups, frequently have scalloped margins and groove-like markings, formed by the ramifications of the auditory nerve. The tongue is frequently absent, and if present is of very simple structure and incapable of protrusion; and since fishes generally bolt their food without mastication, it is probable that they have little, if any, sense of taste. With regard to the digestive organs, it will suffice to mention that in the sharks, rays, and chimeeroids the intestine for a large portion of its length is provided with a spiral valve, a similar structure occurring in the ichthyosaurian reptiles. The gills of sharks, rays, and chimeroids are contained in pouches, usually Coloration. Soft Parts. GENERAL CHARACTERS. 321 five in number on each side; each pouch opening externally by a slit, and also communicating by a separate aperture with the pharynx. In the embryos filamentous gills protrude externally from the slits. The spiracles found on the top of the head in the groups mentioned are the external openings of a canal leading on each side into the pharynx, and represent what is known as the first visceral cleft in the embryo. In the bony fishes the gills, which are generally four in number, he in one undivided cavity on each side of the head, supported by their gill-arches, and covered over by the gill-cover, which is open behind. In ordinary respiration the water is taken in by the mouth, and by a kind of swallowing action driven over the gills, after which it is expelled by the gill- opening. Allusion must be made in this place to certain organs known as false gills, or pseudobranchiw. These are remains of a gill situated in front of the persistent ones, which was functional during embryonic life, but in the adult appears merely as a plexus of blood-vessels. Although the majority of fishes breathe in the manner indicated above, in many forms this is by no means the sole method of respiration. On this subject Day observes that respiration in fishes is carried out normally, either by their using the air which is held in water to oxygenate the blood at the gills, or “by taking in atmospheric air direct, which is employed at a special organ, where it oxygenates the blood, which can be returned for use into the general circulation without going through the gills. The true amphibious fishes respire by the latter method. No doubt we observe that fishes which normally oxygenate their blood solely at their gills do rise to the surface in very hot weather, when the water is foul or insufficiently charged with air, and take in air by the mouth; likewise we find that those which mainly take in atmospheric air direct by the mouth may, to a certain extent, be able to use their gills. If fishes having these two different modes of respiration are placed in a globe of water, across which a diaphragm of net is inserted below the surface, so as to prevent their obtaining access to the atmosphere, those of the class which oxygenate their blood at the gills are unaffected, whereas those which have accessory breathing-organs and take in air direct die from blood-poisoning.” One of the most characteristic organs of fishes is the air-bladder, which is a long sac filled with gas lying in the abdominal cavity, which may be either com- pletely closed, or may communicate with the alimentary tract by means of a duct. As it is susceptible of compression, its usual function appears to be to regulate the specific gravity, or to change the centre of gravity of the fish; but in the lung- fishes it assumes the characters and functions of the lungs of the higher Verte- brates, to which, indeed, it corresponds. Although in the few fishes which produce living young, as well as in the sharks and rays, an actual connection takes place between the two sexes, in the great majority of the class the ova are deposited by the female, after which they are fertilised by the male. The bony fishes lay numerous egos which are of relatively small size and may be extremely minute, those of the eel being almost microscopic; but there is a considerable degree of variation in this respect. In the herring the number of eggs in the “roe” has been estimated at twenty-five thousand, and in the cod at over nine millions. Only im a cat-fish (Aspredo), where they are pressed into the skin of the under surface of the body, VOL. V.—21 Reproduction. 222 FUSHTEES. and a pipe-fish (Solenostoma), where they are carried in a pouch formed by the coalescence of the broad pelvic fins with the skin of the body, is the female known to take any care of her eygs after spawning. Among the bony fishes there are, however, several instances where the young are more or less carefully tended by the male parent; some, like the sticklebacks, building a nest, while others, like certain pipe-fishes, have an abdominal pouch in which the eggs are hatched. The eggs of sharks, rays, and chimeeroids differ remarkably from those of bony fishes, being large in size, few in number, and laid singly instead of in masses. They are invested in a hard horny envelope, which is generally oblong in form, with the four corners produced, and frequently elongated into tendrils by means of which the egg is moored to some foreign substance. The males of these fishes are armed with organs known as claspers, which are partially ossified processes arising from the pubis, and are evidently connected with the function of reproduction. The young of many fishes differ markedly from the adult; and certain peculiar creatures with long ribbon-like bodies and small heads, for which the name of Leptocephali has been proposed, are believed to be the young of littoral fishes which have been carried out to sea, where they have undergone an altogether abnormal development. The changes which take place in the flat-fishes durmg development may be more conveniently noticed under the heading of that group. Although male and female rays differ remarkably from one another in the structure of their teeth, while both in this group and in the sharks and chimeroids the males are distinguished by the possession of the aforesaid claspers, there is generally but little sexual difference among fishes. In the bony fishes, however, the females are larger than the males; among the cyprinodonts the difference between the two being occasionally as much as six times. Fishes. exhibit a remarkable degree of difference in regard to their power of bearing changes from their normal environment. On this subject Dr. Giinther writes that, “some will bear suspension of respiration— caused by removal from water, or by exposure to cold or heat—for a long time, whilst others succumb at once. Nearly all marine fishes are very sensitive to changes in the temperature of the water, and will not bear transportation from one climate to another. This seems to be much less the case with some fresh-water fishes of the temperate zone; since carp may survive after being frozen in a solid Tenacity of Life. block of ice, and will thrive in the southern parts of the temperate zone. On the other hand, some fresh-water fishes are so sensitive to a change in the water that they perish when transferred from their native river into another apparently offering the same physical conditions. SSome marine fishes may be abruptly trans- ferred from salt into fresh-water, like sticklebacks; others survive the change when gradually effected, as many migratory fishes; whilst others, again, cannot bear the least alteration in the composition of the salt-water (all pelagic fishes). On the whole, instances of marine fishes voluntarily entering brackish or fresh- water are very numerous, whilst fresh-water fishes proper but rarely descend into salt water.” The foregoing remarks lead naturaliy to the subject of the dis- tribution of fishes; a subject which the limits of space compel us to dismiss with a few sentences. In the first place, we find that many marine fishes Distribution. DISTRIBUTION. 323 have a much less wide geographical distribution than might at first sight be expected; while, on the other hand, we find families and genera, and even species, of fresh-water fishes inhabiting widely separated areas of the earth’s surface. The primary division into fresh-water and marine fishes does not form such a sharply defined boundary as is commonly supposed; the transition being formed by the brackish-water types, species or even individuals of which can accustom themselves to live in either salt- or fresh-water. Then, again, we have certain essentially fresh-water fishes, like the salmon and some kinds of eat-fish, which pass a certain period of their existence in the ocean; while, on the other hand, some marine forms, such as sturgeons, periodically ascend rivers for the purpose of spawning. To a certain extent such habits will help to explain the occurrence of peculiar families of fresh-water fishes (such as the chromids of Africa, South America, and India) in widely separated areas, although this must probably be supplemented by dispersal from a common northern centre. After the separation of the fresh-water and brackish-water types, the marine fishes are divided by Dr. Giinther into a littoral, a pelagic, and a deep-sea group, although here, again, no hard-and-fast lines can be drawn. The littoral or shore- fishes are those found in the immediate neighbourhood of land or sunken shoals ; the majority living close to the surface, and very few descending as deep as three hundred fathoms. Their distribution is determined not only by the temperature of the surface-water, but likewise by the nature of the neighbouring land, and its animal and vegetable products; some of these fishes being suited to inhabit flat coasts with muddy or sandy bottoms, while others frequent rock-bound shores where the water is deep, and others, again, congregate round coral-reefs. Cod, rays, and flat-fish are well-known examples of this group. Pelagic fishes, such as tunnies, flying-fish, sword-fishes, and sun-fishes, inhabit the superficial layers of the open ocean, approaching the shores only by accident, or in some cases in search of food, or for the purpose of spawning. Dr. Giinther writes that, “with regard to their distribution, they are still subject to the influences of light and the tempera- ture of the surface-water; but they are independent of the variable local conditions which tie the shore-fish to its original home, and therefore roam freely over a space which would take a fresh-water or shore-fish thousands of years to cover in its gradual dispersal. Such as are devoid of rapidity of motion are dispersed over similarly large areas by the oceanic currents, more slowly than, but as surely as, the strong swimmers.” In marked contrast to the last are the deep-sea fishes, inhabiting the abyssal depths of the ocean, where they are undisturbed by tides or currents, and live for the most part in total darkness; their organisation, in consequence of the great pressure of the medium in which they live, preventing them from coming to the surface in a healthy condition. From the similarity in the physical conditions of the ocean-depths in all parts of the world, there seems no reason why a single species of deep-sea fish should not range from the Equator to the Poles; and the abyssal fauna is probably more or less nearly the same throughout the globe. These fishes belong for the most part to pelagic families, and especially to such types as are of nocturnal habits; and are characterised by their generally black or silvery colour, although in a few instances the fin-rays and certain filaments are scarlet. Writing of those fishes, Dr. Giinther observes that, “the organ of sight is the first to be affected by a sojourn in deep water. Even in fishes which habitually live at a depth of only eighty fathoms, we find the eye of a proportionately larger size than in their representatives at the surface. In such fishes the eyes increase in size with the depth inhabited by them, down to the depth of two hundred fathoms; the large eyes being necessary to collect as many rays of light as possible. Beyond that depth, small-eyed as well as large-eyed fishes occur; the former having their want of vision compensated by tentacular organs of touch, while the latter have no such accessory organs, and evidently only see by the aid of phos- phorescence. In the greatest depths occur blind fishes, with rudimentary eyes, and without special organs of touch. Many fishes of the deep sea are provided with more or less numerous, round, shining, mother-of-pearl-coloured bodies, embedded in the skin. These so-called phosphorescent or luminous organs are either bodies of an oval or irregularly elliptical shape placed in the vicinity of the eyes, or smaller globular bodies arranged symmetrically in series along the sides of the body and tail.” That the function of these bodies is to produce phosphorescent light may be considered certain; and it is probable that both the tentacles and the whole surface of the bodies of these extraordinary fish are also phosphorescent. Not the least remarkable feature about the carnivorous deep-sea fishes is the enormous size of their stomachs, which enable them to swallow creatures nearly as large as them- selves; drawing themselves over their prey almost after the manner of a sea- anemone. Although when brought to the surface deep-sea fishes are soft, flabby creatures, with their scales standing out at right angles, and their eyes starting from their sockets, at their own proper level, under an enormous pressure, their bodies are doubtless as firm and compact as those of ordinary fish. Deep-sea fish certainly live at a depth of two thousand seven hundred and fifty fathoms. In regard to geological distribution, it has already been mentioned that the oldest true fishes occur in strata of upper Silurian age; such early fishes being sharks. In the succeeding Devonian and Carboniferous periods, the class was abundantly represented, but only by sharks, fringe-finned ganoids, and lung-fishes. In the Permian, Triassic, and Jurassic periods chimeroids, as well as the chondrosteous Teleostomi made their appearance; but it was not till the Cretaceous epoch that the higher bony fishes, which are the predominant forms in the Tertiary period and at the present day, were developed. There are fully nine thousand known species of living fishes, while considerably more than one thousand fossil forms have been already described. CH APT ER THe Lune-FisHes AND CHIMa&ROIDS,—Subclasses Dipnot anp HoLocrPHAtti. THE two first subclasses of fishes agree with one another, and thereby differ from the remaining two, in the structure of the skull, in which the hyomandibular bone is welded with what is known as the palatopterygoid bar (that is to say, the bones corresponding with the palatines and pterygoids of the higher Vertebrates), which is itself firmly united to the cranium proper, so that there is no separate structure for the suspen- sion of the lower jaw. To this type the name of solid-skulled (technically, autostylic) fishes may be applied; and it may be noted that this type of structure is essentially the same as that on which the skulls of the Amphibians are formed. In the lung- fishes the skeleton is par- tially ossified, with well- developed membrane- bones; the gill-clefts are but slightly separated, and open into a single cavity protected by an external cover; and the external skeleton consists of true bony tissue. In _ the existing members of the group the optic nerves (or BE proeseing, fron thoy mic, ont pone ation pe Gene ol le brain to the eyes) simply cross one another, without any interlacing of the constituent fibres: the intestine has a spiral valve; the air-bladder is elongated, and performs the functions of a lung; and the nostrils open posteriorly by two apertures into the cavity of the ROOF OF THE SKULL OF THE AUSTRALIAN LUNG-FISH. 326 LONG-FISHES. mouth, after the manner of the higher Vertebrates. The membrane-bones covering the roof of the skull, which are very few in number, cannot be correlated with those of the bony fishes; their mode of arrangement being shown in the accom- panying figure. The lung-fishes are at the present day represented only by three genera, with but very few species, but they were formerly a very numerous group, which appears to have been on the wane since a very early epoch. Toe Existinc Luna-FIsHes.—Family LEPIDOSIRENID 2. The three existing genera of lung-fishes may be taken as the typical repre- sentatives of an order including several extinct families, and known as the Sirenoidea. Its essential characters are that the head is covered with membrane- bones; that the main dentition takes the form of large grinding plates, situated on UPPER PALATAL TEETH OF AN EXTINCT LUNG-FISH (Ceratodus). (From Teller.) the pterygoid bones in the upper, and on the splenials in the lower jaw; that the body is covered externally with overlapping scales; that the notochord persists throughout life; that the paired fins are of the fringed type; and that none of the fins are armed with spines. The existing forms have but few membrane-bones to the skull; no premaxillee, maxille, marginal teeth, or jugular plates; a fringed tail, furnished with a continuous vertical fin; and cycloid scales. Australian For a great number of years there were known from the Triassic Lung-Fish. strata of various parts of Europe fish-teeth of the remarkable type of the specimen represented in the accompanying figure; and from the fancied resemblance to a deer’s antler, presented by these teeth, the name of Ceratodus was suggested for the otherwise unknown fishes to which they pertained. Similar teeth were subsequently obtained from Secondary rocks in India and also in South Africa, but it was not until the year 1870 that a fish was discovered in Queensland having teeth of asimilar type. Known to the natives, in common with other large fresh-water species, by the name of barramundi, the Australian lung-fish (C. forsterc) agrees so closely with the extinct forms that it is usually regarded as generically identical. Its mouth is furnished in front with a pair of chisel-like teeth situated on the vomers, behind which come a pair of palatal teeth of the type of the one shown in the figure, but carrying six complete ridges, and an incomplete seventh ; EXISTING GROUP. 327 while there are a pair of similar teeth in the lower jaw, carrying only six ridges each. In the living species the teeth of opposite sides are separated by an interval ; but in the fossil forms they were in contact, and had fewer ridges. The existing Australian lung-fishes, of which two species have been described, are said io attain a weight of 20 lbs, and.a length of upwards of 6 feet. The body is elongated and much compressed, with very large scales; the paddle-shaped limbs have very broad fringes; and the flesh is salmon-coloured. From the occurrence of masses of leaves in its stomach it is evident that the Australian lung-fish crops the vegetation with its great teeth; but it is believed that the most important part of its food consists of the small creatures living on and between the leaves of the AUSTRALIAN LUNG-FISH (4 nat. size), various water-plants. The stories of the fish coming out of the water to the land seem quite unfounded, as are those that it lies dormant during part of the year in cocoons. The female lays her rather large eggs loosely and singly among the vegetation, and in the embryo the fore-limbs make their appearance in about a fortnight, but the hinder-pair not before two and a half months. In the course of its development this fish presents marked resemblances to the Amphibians, and also to the lampreys; but it is noteworthy that there is no trace of a sucking mouth, or of external gills. As might have been inferred from the study of allied extinct forms, the large palatal teeth are formed by the fusion of a number of separate small teeth. According to Dr. Semon, the Australian lung-fish is confined to the middle portion of the Burnett and Mary Rivers of Queensland. Living among the 328 LONGTISHES. 7) mud and leaves at the bottom, it rises at intervals to the surface to obtain more complete oxygenation of its blood by the inhalation of atmospheric air into its lungs, although its general breathing is carried on by the gills. 392 SPINY-FINNED GROUP. of moderate size, and the caudal vertebrae unusually numerous. While the majority of these fishes are confined to the northern temperate seas, a few extend into the Indian Ocean and as far south as Penang. The remarkable fishes known as hairy-backs constitute another small family (Z’richonotide) distinguished from the last by the jugular position of the pelvic fins, which are in front of the pectorals; there being one or two spineless dorsal fins, an elongate anal fin, which is also spineless, and no papille in the neighbourhood of the vent. The typical genus is represented by a single species (T'richonotus setiger) from the Oriental seas, characterised by the first few rays of the single dorsal fin being isolated and more or less elongate, and likewise by the lower jaw exceeding the upper in length. The New Zealand thorny-nose (Hemerocoétes acanthorhynchus) represents a second genus, differing Hairy-Backs. NEW ZEALAND THORNY-NOSE. from the last by all the rays of the long dorsal being in juxtaposition, by the upper jaw being longer than the lower, and the presence of horny processes on the muzzle. These fishes are not unfrequently found floating on the surface of the ocean at a considerable distance from land. The most remarkable representatives of a third small family (Chiride) of this group constitute the genus Chirus, which is peculiar in having several lateral lines, the number of these varying in the different species. The family differs from the two preceding ones in that there is a bony stay con- necting the preopercular with the infraorbital ring; while it is further distinguished by the single dorsal having its spinous and soft portions of nearly equal length ; the anal being nearly equal in length to the soft dorsal, and the pelvies thoracie in position, with one spine and five rays. The compressed and oblong body is sealed, the cleft of the mouth lateral, and the teeth are weak. All the members of the family are small littoral fishes, inhabiting both sides of the Northern Pacitfie; the Chirus. ttn an BLENNIES. 393 figured species (Chirus hexagrammus) being from Japanese waters. In the other genera the lateral line is single. The fourth family of the group (Blenniide) is much more extensive than either of the others, comprising a considerable number of genera, some of which are rich in species. The family agrees with the hairy-backs in the jugular position of the pelvic fins, which, when present at all, are composed of a very few soft rays. In the anal fin, the spines are few or wanting, and there is very generally a papilla in the neighbourhood of the vent. The low and elongate body is more or less cylindrical in form, and either naked or covered with scales, which are generally of small size. The dorsal fin, which may be either single, double, or triple, occupies nearly the whole length of the back; and when it has a distinct spinous portion, this is at least as much developed as the soft part, while in some instances the whole fin may be spiny, the anal being Blennies. JAPANESE CHIRUS. elongate. In most cases false gills are present. All the marine members of the family are littoral forms, and the majority are of small size, while some are among the smallest of all fishes. They are abundant throughout all tropical and temperate seas; and whereas some forms inhabit brackish water, others are exclusively fresh- water. Dr. Giinther writes that “one of the principal characteristics of the blennies is the ventral [pelvic] fin, which is formed by less than five rays, and has a jugular position. The blennies have this in common with many gadoids [cod tribe], and it is sometimes difficult to decide to which of these two families a fish should be referred. In such doubtful cases the presence of the pseudobranchize (which are absent in gadoids) may be of assistance. In many blennies the ventral fins have ceased to have any function, and become rudimentary, or even entirely absent. In others, the ventral fins, although reduced to eylindrical stylets, possess a distinct function, and are used as organs of locomotion, by the aid of which the fish moves over the bottom.” The family is not definitely known in a fossil state, although it may be represented by an extinct genus in the Monte Bolea Eocene. 394 SLINYV SINNED GRO OL, The blennies of the typical genus Blennius, of which there are some forty species, are found in the northern seas, the Tropical Atlantic, the coasts of Tasmania, and the Red Sea. They are characterised by the moderate elongation of the naked body, the short snout, the single continuous dorsal fin, and the presence of one spine and two rays in the pelvics. The cleft of the mouth is narrow, the jaws contain a single series of fixed teeth, behind which there is generally one larger curved tooth, at least in the lower jaw. Above each eye is the longer or shorter tentacle, and the gill-opening is relatively wide. Among British species we have the eyed blenny (B. ocellatus), distinguished by the dark spot on the elevated spinous portion of the dorsal, the smooth blenny or shanny B. pholis, and the large B. gattorugine, which may grow to a foot in length; while as an example of a species living in inland lakes we may cite the fresh-water blenny (B. vulgaris) of Southern Europe. Most can be readily accustomed to a fresh-water life, and many of the marine species attach themselves to floating objects, while some are found far out at sea among the patches of drifted seaweed. In the Indian seas the blennies are represented by seven more or less closely allied genera, in one of which (Xiphasia) the body is band-like, and the caudal fin continuous with the dorsal and anal. Viviparous The fish (Zoarces viviparus) of which two examples are repre- Blennies. sented in the lower part of the illustration on p. 387, is one of two species of a genus remarkable for producing living young. With an elongate body, rudimental scales, and conical teeth in the jaws, these fish have an extremely elongated dorsal fin, separated from the caudal merely by a depression formed by a series of spines much shorter than the rays; these spines being the only ones throughout the fins. The pelvic fins are composed of three or four rays: and the long anal fin is continuous posteriorly with the caudal. The gill-openings are wide. While the figured European species, which is not uncommon on the British coasts, does not exceed a foot in length, its Transatlantic cousin (Z anguillaris) may measure two or three times as much. The fry, which at birth are perfectly transparent, and form beautiful objects for the microscope, are so fully developed as to be able at once to swim freely on leaving the body of the female parent. Before their birth the female becomes so distended, that at the slightest pressure the young are extruded; these frequently being from two to three hundred in number, and always making their appearance in the world head first. The general colour of the adult fish is pale brown, with the dorsal fin and upper-parts mottled and barred with darker brown. Easily recognised by the powerful tuberculated and molar-like teeth with which their mouths are armed, the wolf-fishes (Anarrhi- chas) may be regarded merely as gigantic and somewhat specialised blennies. In this genus, which is represented by a small number of species from the northern seas of both the Eastern and Western Hemispheres, the elongate body is covered with rudimental scales; the muzzle is rather short and the cleft of the mouth wide; and the jaws are armed with strong conical teeth, those of the lateral series carry- ing several pointed cusps, while a double row of large molar-like teeth runs down the middle of the palate. The long dorsal fin has flexible spines, and there is a distinct caudal, but the pelvic pair are quite wanting. The gill-opening is wide. Wolf-Fishes. LLY eS, 395 o The common wolf-fish (A. lupus), often known as the sea-wolf or sea-cat, ike two allied species, ranges as far north as Norway and Greenland; in both of which countries its flesh forms a staple article of food. Oblique-Spined The fifth family (Acanthoclinide) of the section under con- Blenny. —_ sideration is represented only by the New Zealand oblique-spined blenny (Acanthoclinus littoreus), shown in the annexed illustration, and is charac- terised by the elongate, low, compressed, and scaly body, the single dorsal fin— chiefly composed of spines—occupying nearly the whole length of the back, and the comparatively long and many-spined anal; the pelvic fins being jugular in position, and consisting solely of a few soft rays. On the coasts of New Zealand this blenny is stated to be a very common fish; its habits being probably similar to those of its European cousins. OBLIQUE-SPINED BLENNY (nat. size). The so-called spiny eels of the Oriental region and West Africa form a family (Rhynchobdellide) affording an interesting example of parallelism in development, since these spiny-finned eels are an exact analogue of the true soft-finned eels. They are characterised by the elongate eel-like form of the body; the long dorsal fin, of which the anterior portion consists of short isolated spines; and the absence both of pelvic fins and of a papilla in the neighbourhood of the vent. The gill-opening forms a slit on the side of the head ; four gills are contained in the gill-chamber, and there are no false gills. An elongated movable appendage forms the termination of the muzzle, and although the lower jaw is long, it has but little power of motion. As an especial peculiarity of these fishes, we may notice that in the skeleton there is no connection between the pectoral girdle and the skull. The air-bladder is present. The species (Mastacembelus armatus), shown in the upper figure of the illustration on p. 396, is one of the Indian representatives of a genus characterised by the smooth under surface of the appendage of the snout, and the presence of a preorbital spine. The members of this genus have a geographical distribution, coextensive with that of the family, being found in the brackish and fresh waters of West Africa, India, Ceylon, Burma, and the Malayan region. On the other hand, Spiny Eels. 396 SPINY-FINNED GROUP. the genus Rhynchobdella, characterised by the striation of the lower surface of the nasal appendage, and the lack of a spine in front of the eye, is confined to India and Burina, where it is represented by R. aculeata, which grows to a length of about 15 inches, and is found in the deltas of all the larger rivers, generally preferring muddy pools. The figured species is, however, of larger size, reaching a couple of feet in length. The flesh of all the spiny eels is stated to be of excellent quality for the table. The fish represented in the lower portion of the annexed illus- tration, known as the Baikal oil-fish (Comephorus baikalensis), is the only representative of a genus in regard to the systematic position of which there is considerable doubt; Dr. Giinther regarding it as indicating a distinct family which he at one time placed in the neighbourhood of the oblique- Oil-Fish. SSS = SS === — ot INDIAN SPINY EEL (} nat. size). BAIKAL OIL-FISH (4 nat. size). spined blenny, and afterwards near the flying gurnards. In this fish the body is elongate and naked, the head large with a produced muzzle, medium-sized lateral eyes, and small teeth. There are two dorsal fins, of which the first is much shorter than the second, which is similar to the anal; the pelvic fins are wanting, and there is no papilla near the vent. The gill-opening is wide ; there are four gills, and no air-bladder. The skeleton is very soft; and the elements of the gill-cover are not distinctly differentiated. In colour this strange fish is uniformly greenish, and_ its pectoral fins are remarkable for their large size. While the oil-fish presents some resemblance to the dragonets, it differs by the compressed body, the large, broad-snouted head, the elongation of many of the rays of the second dorsal fin, the large pectorals, the absence of pelvic fins, and the forked tail. So far as present information goes, the oil-fish is confined to Lake Baikal, where in winter it retires to the greatest depths, but approaches BARRACUDAS AND SAND-SMELTS. 397 the shore in the warmer months. Swimming with remarkable speed, it is enabled by the length of its pectorals to take considerable leaps above the surface of the water, and thus approaches the flying-fish. During stormy weather great numbers of these fishes are frequently stranded, when they are collected by the natives for the purpose of extracting the oil from them. BARRACUDAS, ATHERINES, AND GREY MULLETS,—Families SPHYR.ZNIDZ, ATHERINID4, and MUGILID. Following Dr. Giinther’s classification, these three families form a sectional group differing from those we have been considering by the position of the pelvic fins, Which are abdominal, and have one spine and five soft rays. The two dorsal fins are situated more or less remote from one another, the first being either short, like the second, or composed of weak spines. The large and ferocious fishes commonly known as barracudas (Sphyrena), of which a species (S. vulgaris) is shown in the upper figure of the illustration on p. 379, are the sole existing representatives of the first family, which is distinguished by the elongated and subcylindrical form of the body, the large cutting-teeth, the continuous lateral line, and the presence of only twenty-four vertebre in the backbone. The scales are small and cycloidal ; Barracudas. the cleft of the mouth is wide; and the medium-sized eyes have a lateral position. Represented by something less than a score of species, barracudas are distributed over all temperate and tropical seas, but generally prefer the neighbourhood of the coast to the open ocean. ‘They are all carnivorous and fierce in their dis- position, and since they frequently grow to 6 or 8 feet in length, they are as much or even more dreaded by bathers in seas where they are common than sharks. They are extensively caught for food, but in some instances, from their having fed on poisonous kinds of fish, their own flesh becomes impregnated with the venom. Moseley writes that “there is a great fishery at the Cape, of a fish called snook, a kind of barracuda, which is salted and dried, and sent mainly to Mauritius for sale. The snook-boats were always to be seen about in the bay. The fish are caught with a hook and line whilst the boat is in motion. The fishermen are especially careful not to get bitten by the fish as they haul them in, wounds caused by their bite being said to fester in a violent manner, as if inflamed.” Fossil barracudas occur in the middle Eocene of Monte Bolea; while in the Cretaceous rocks of the Lebanon and Brazil the family is represented by the extinct genus Cladocyclus. The second family of the group under consideration is typically eae represented by the so-called sand-smelts; one of the two British species (Atherina hepsetus) being shown in the left figure of our illustration. As a family, the Atherinidw are distinguished from the barracudas by the indistinct lateral line; the feeble or moderately developed dentition; and by the number of vertebre being usually in excess of twenty-four, The body is more or less elongate, with but slight compression. In the sand-smelts the scales are smooth and eycloid, and the teeth minute; the first dorsal fin is short and completely separate from the second; and the muzzle is blunt, with the cleft 398 SPINY-FINNED GROUP. of the mouth straight, oblique, and extending at least as far back as the lne of the border of the eye. These fish derive their popular title from their resemblance to the true smelts, from which they may be distinguished at a glance by the small spinous first dorsal fin. While the majority are coast fishes, associating in large shoals, others are fresh-water, although these also retain the same habit. The genus has a wide distribution in temperate and tropical seas, some of the species ranging from Eastern Africa to India. Atherines are very abundant in the Mediterranean, where the fry cling together for some time after hatching in enormous masses. Montagu writes that these fish are caught in great abundance on the south coast of Devonshire “in the ereeks and estuaries, but SAND-SMELT AND CUVIER’S SQUARE-TAIL (4 nat. size). never in rivers above the flow of the tide; and they appear to continue near shore through the months from autumn to spring, being caught for the table more or less during the whole of that time, but are greatly superior in spring, when the males are full of milt as the females are of roe.” The British species seldom exceed 6 inches in length, and, like the other members of the genus, are marked by a broad silvery stripe along each side of the body. On the coasts and in the fresh waters of Australia, the sand-smelts are represented by Atherin- ichthys, in which the muzzle is longer, and the cleft of the mouth usually shorter. The curious Mediterranean and Atlantic fish known as Cuvier’s square-tail (Tetragonurus cuvierr), shown on the right side of our illustration, is the sole member of a genus characterised by the somewhat elongate Square-Tail. ——— GREY MULLETS. 399 body being covered with strongly keeled and striated scales; and by the first dorsal fin being composed of a number of short spines, and continuing to the second. The elevated lower jaw has a convex upper border, bearing a single series of rather small compressed and triangular teeth. Of the habits of this scarce fish nothing definite seems to be known; although in the young state it is found in company with floating jelly-fish. At a later period of its existence it probably descends to a considerable depth during the day, and comes to the surface only at night. It grows to a foot and a half in length. From the two preceding families the grey mullets, which con- stitute the third family of the group under consideration, may be distinguished by the total absence of a lateral line, the presence of only four stiff spines in the first dorsal fin, and the limitation of the number of vertebra in the skeleton to twenty-four. The more or less elongate and somewhat compressed body is covered with cycloid or shghtly ctenoid scales of moderate size; the cleft Grey Mullets. COMMON GREY MULLET (¢ nat. size). of the mouth is small or medium; the teeth are feeble or wanting; the lateral eye is of moderate size; and the gill-opening wide. In some species there may be a fatty lid to the eye. The grey mullets (M/ugil), of which there is a very large number of species, are distributed over all temperate and tropical coast-regions, frequenting brackish-water estuaries, and in some cases ascending rivers for considerable distances. Feeding chiefly upon the animals and organic matter found in sand and mud, these fishes have a special straining apparatus in the pharynx for the purpose of preventing objects of too large size from entering the stomach, or foreign substances getting into the gill-chamber, It will be unnecessary to describe the structure of this apparatus here; but it may be mentioned that after triturating a mouthful of sand or mud between the pharyngeal bones, in order to extract such nutriment as it may contain, the grey mullets reject the mineral part of it. Another peculiarity is to be found in the structure of the cesophagus and stomach, the former being lined with long thread- like papillee, while the latter has its second portion furnished with muscular walls like the gizzard of a bird, although it is not divided into two lateral halves. 400 SPINY FINNED “GROGL. A fossil species of grey mullet has been described from the upper Eocene of Provence, and an extinct genus from the Cretaceous. Our figure represents the common grey mullet (J/. capito), one of several species frequenting the British coasts. Although this mullet only grows to a weight of about 4 lbs., some of the foreign species may scale three times as much. This mullet has been kept in a fresh-water pond, where it seemed to thrive better than in the sea. The flesh of all the grey mullets is of good quality, but bears no comparison to that of their red namesakes. GarR-PIKE AND FLyINnc-FisH,—Family SCOMBRESOCID, In this place may be noticed a family in regard to the serial position of which there is some difference of opinion, Dr. Giinther placing it among the tube-bladdered fishes, while Professor Cope considers that its true position is here. The inclusion of the group among the tube-bladdered fishes utterly spoils the definition of that suborder, since in those members of the present family provided with an air- bladder that organ lacks a duct. It is true that the fins of the flying-fishes and their allies are less spiny than those of the more typical representatives of the suborder under consideration, but, as we have seen, this character is one of but slight morphological value. Agreeing with the preceding section in the abdominal position of the pelvic fins, these fishes differ from those yet described, with the exception of certain perches, in the union of the lower pharyngeal bones; while they are further characterised by the absence of a spinal dorsal fin, and the deeply forked caudal. The single dorsal is situated opposite to the anal fin in the caudal region, the air-bladder is generally present, the false gills are hidden and glandular, and the simple stomach merely forms a dilatation of the intestinal tract. Although the majority of the members of this family are marine, some being pelagic, a few have taken to a fresh-water existence; and while many of the latter are viviparous, the whole of the others deposit eggs in the usual manner. Dis- tributed over all the temperate and tropical seas, these fish are strictly carnivorous in their habits. Geologically, the family is a comparatively ancient one, the gar- pike being represented by an extinct species in the Sicilian Miocene, and by an allied extinct genus in the Eocene of Monte Bolea, while a fish nearly allied to the living flying-fishes occurs in the Cretaceous rocks of the Lebanon. In North America it appears that the name “ gar-pike ” is applied indifferently to a member of the present family, and to the very distinct fish also known as the bony pike; but in scientific nomenclature it will be better to confine the term to the members of the present genus. Gar-pike are represented by nearly fifty species from temperate and tropical seas, among which the figured one (belone vulgaris) is common on the British coasts, likewise ranging over the whole of the seas of Northern Europe. As a genus, these fishes are easily recognised by the production of the jaws into a long slender beak, formed in the upper one exclusively by the premaxillary bones; while they are further characterised by the whole of the rays of the dorsal and anal fins being connected by membrane. The beak is, however, only developed in the adult, very young specimens having the jaws of normal form; and it is not a little remarkable that Gar-Pike. GAR-PIKE AND FLYING-FISH. 401 during their development the lower jaw becomes for a time much longer than the upper one. Both jaws are beset with a number of rugosities, and likewise with a series of long, conical teeth placed at considerable intervals. A peculiarity of these fish is to be found in the green colour of their bones. Whereas the British species does not exceed a couple of feet in length, some of the foreign repre- sentatives of the genus may grow to as much as 5 feet. Dr. Gunther writes that, skimming along the surface of the water, the gar-pike seize with their “long jaws small fish, as a bird would seize them with its beak; but their gullet is narrow, so that they can swallow small fish only. They swim with an undulating motion of the body; but although they are in constant activity, their progress through the water is much slower than that of the mackerels, the shoals of which sometimes appear simultaneously with them on our coasts.” Frequently they may be seen leaping out of the water over small floating objects in sportive play, and when GAR-PIKE (4 nat. size). struck by the hook throw themselves above the surface in violent contortions. The saury, or skipper (Scombresox saurus), is the British representative of a much smaller genus, differing from the gar-pikes by the minute size of the teeth, and likewise by the presence of a number of small finlets behind the dorsal and anal fins. On the other hand, the half-beaks (Hemirhamphus), some of which inhabit fresh water, have the lower jaw larger than the upper throughout life. Perhaps few sights are more pleasing during a long sea-voyage in an ocean steamer than to stand in the bows and to watch the flying-fish rising—sometimes singly, but more frequently in larger or smaller shoals—from beneath the vessel to take their beautiful flight over the crest of the waves, till they once more disappear from view beneath the deep blue waters. Represented by more than forty species from tropical and subtropical seas, the flying- fishes, of which the common species (Hxoceetus evolans) is shown in the illustration on p. 314, form a genus which may be at once recognised by the great length of VOL. V.—26 Flying-Fish. 402 SPINY-FINNED GROUP. the pectoral fins. They are further characterised by the blunt and short-jawed head, and the moderately long oblong body invested in a coat of rather large-sized scales; the teeth, when present at all, being minute or rudimental. The ordinary length of a flying-fish is from 10 inches to a foot, although specimens are occasionally met with half as long again; and whereas the common form ranges round the world, the distribution of some other species is extremely restricted, one being recorded only from the seas on the Pacific side of the Isthmus of Panama. The species differ considerably in the length of the pectoral fins; those in which they reach to the tail-fin being capable of taking the longest flights, whereas in some others they do not extend beyond the anal. Associating in shoals, which are sometimes of immense size, all these fish are pelagic in their habits, and all are capable of taking the skimming flight from which they derive their name. That these fish take their flights primarily to escape from their enemies may be regarded as certain; and it is equally well ascertained that the continuance of the flight is due to the original impetus of the leap from the water, and is not prolonged by any flapping of the fins. From my own observations I am, however, of opinion that the pectoral fins are vibrated rapidly on first leaving the water for a few seconds, doubtless from a continuation of the swimming motion while in the water, after which they become entirely motionless. During flight, the colour of these fins may appear either white or brown, when seen from above, according to the incidence of the light. So far as I have seen, flying-fish are unable to change the direction of their course to any marked extent; but on this point, as will be seen from the two following accounts, there is some difference of opinion among observers. The first of these two accounts is abridged by Dr. Giinther from one published by Dr. Mobias, and runs as follows: “ Flying-fish are more frequently observed in rough weather and in a disturbed sea than during calms; they dart out of the water when pursued by their enemies, or frightened by an approaching vessel, but frequently also without any apparent cause, as is also observed in many other fishes; and they rise without any regard to the direction of the wind or waves. The fins are kept quietly distended, without any motion, except an occasional vibration caused by the air whenever the surface of the wing is parallel with the course of the wind. Their flight is rapid, but gradually decreasing in velocity, greatly exceeding that of a ship going ten miles an hour, and extending to a distance of five hundred feet. Generally, it is longer when the fish fly against than with, or at angle to the wind. Any vertical or horizontal deviation from a straight line is not caused at the will of the fish, but by currents of the air; the fish retaining a horizontally straight course when flying with or against the wind, but being carried to one side whenever the direction of the latter is at an angle to that of their flight. It may, however, happen that in the course of its flight a fish may dip its tail in the crest of a wave, thus changing its direction to the left or right. In calm weather the line of flight is always also vertically straight, or rather parabolic, like the course of a projectile, but in a rough sea, when the fish are flying against the course of the waves, it may become undulating. In such instances the flying-fish frequently overtop each wave, being carried over by the pressure of the disturbed air. Flying-fish often fall on board vessels, but this never happens during a calm, or from the lee-side, always taking place in a breeze STI CELEBACTSS, 403 and from the weather-side. In the daytime they avoid a ship, flying away from it; but, during the night, when they are unable to see, they frequently fly against the weather-board, where they are caught by the current of air, and may be thus carried to a height of some twenty feet above the surface of the water.” In the second account, which was published many years ago in Land and Water, the author writes that in calm weather flying-fish “are capable of clearing three hundred yards. Their flight is frequently extended to double the distance by simply skimming the surface, as a swallow does a pool, and without disappearing. I have observed that they never touch the surface more than twice consecutively, though they may resume their flight after a period of complete immersion ; while still in the air, they readily change their course to right angles with their first line of flight, or even completely reverse it towards the point from which they originally started. I have watched them for hours through a powerful double glass, as they rose from either side of the bows of the ship, and noticed that the pectoral fins are moved with a slight but very rapid quivering motion, which, I have no doubt, assists to sustain them in the air. In rough weather the flight of the flying-fish is more rapid, much higher, and of shorter duration than when light winds prevail.” This account confirms my own observations as to there being a vibratory motion of the pectoral fins when first leaving the water, although the writer is probably incorrect in his supposition that this assists the flight. STICKLEBACKS, FLurE-Moutus, AND TRUMPET-FISH,—Families G.ASTROSTEIDZ, AULOSTOMATIDA, and CENTRISCIDA. Although the third of the above-named families is regarded by Dr. Giinther as forming a group apart, we may follow Day in placing the whole three in a single section, characterised by the spinous dorsal fin, when present, being either short or formed of isolated spines, and by the generally abdominal position of the pelvic fins, which in some instances are imperfectly developed. Bey cite) Familiar to every home-born Englishman as the fish upon which, in common with minnows, he made his first experiment in angling with the aid of a bit of twine, a bent pin, and a worm, the sticklebacks have the honour not only of representing a genus ((astrosteus), but likewise a family by themselves. Taking their name from the presence of a variable number of isolated spines in advance of the soft dorsal fin, sticklebacks have the body more or less elongate and compressed, the cleft of the mouth oblique, and the teeth villiform. The gill-cover is unarmed, and the cheek covered by the infraorbital bone; and in place of scales there are generally large plates along the sides of the body. The pelvie fins, although abdominal in position, are connected with the pectoral girdle by means of the pelvic bones, and consist of but one spine and a single ray; and there are but three branchiostegal rays. Confined to the Temperate and Arctic zones of the Northern Hemisphere, where they are represented by some half-score species of small bodily size, sticklebacks are mainly fresh-water fishes, although the sea-stickleback (G. spinachia) is a marine or brackish-water form, and all the rest can live as well in salt as in fresh-water. The British fresh-water repre- sentatives of the genus are distinguished by the number of the dorsal spines, and 404 SPINY-FINNED GROUP. are known as the three-spined (G. aculeatus), four-spmed (G. spimulosus), and nine- spined sticklebacks (@. pungitius); while in the United States G. novaeboracensis is the most familiar kind. The three-spined stickleback is a singularly variable species, the plates which are present on the sides of the body in some specimens, being wanting in others; the unprotected condition being especially common in the race from Central Europe. Very different in appearance from the others is the fifteen-spined, or sea stickleback, in which the body is very long and thin; this species ranging as far north as Norway and the Baltic. It has recently been ascertained that all the individuals of this stickleback die within a year of their GROUP OF STICKLEBACKS. Sca-stickleback (upper figure) ; Nine-spined stickleback (middle figure) ; and Three-spined stickleback (lower figure), (nat. size). birth; so that we have here a second example of an annual vertebrate, the first being the one mentioned on p. 389. Sticklebacks are extremely pugnacious, and at the same time highly voracious fishes, the males engaging in fierce conflicts with one another; while both sexes 5 consume a vast quantity of the fry of other fish, and are, therefore, most objec- tionable denizens of preserved waters. It is not, indeed, that a single stickleback can do a very great deal of harm, but the mischief results from the enormous numbers of these little marauders. As an instance of this, we may once more quote the well-known statement of Pennant, that a man employed by a Lincoln- shire farmer to rid a stream of sticklebacks, for a considerable time made four shillings a day by selling his catch at the rate of a halfpenny per bushel. In STICKLEBACKS AND FLUTE-MOUTHS. 405 fighting, the males make full use of the formidable spines on the back, with which they have been seen to rip open the body of an antagonist. The most interesting trait in the economy of sticklebacks is, however, undoubtedly the nest-building habit of many of the species. In the sea-stickleback the nest is composed of a mass of pendent seaweeds, bound together by a silk-like thread into a pear-shaped form, in the centre of which are deposited the eggs. Such a nest has been known to be guarded for a period of upwards of three weeks by the male parent fish ; and when it sustained any damage, by which the eggs were exposed to view, the watchful guardian set about repairing the mischief with the greatest despatch and energy, thrusting its nose deep into the structure, and pushing and pulling the materials till all was once more sound. The following account of the nesting of the three-spined stickleback in an aquarium was forwarded by a correspondent to Frank Buckland. On this occasion the male “selected a spot nearly in the centre of the trough, and busily set to work to make a collection of delicate fibrous materials, placed on the ground, and matted into an irregularly circular mass, somewhat depressed, and upwards of an inch in diameter, the top being covered with similar materials, and having in the centre a rather large hole. His work was commenced at noonday, and was completed, and the eggs deposited by half- past six in the afternoon. Nothing could exceed the attention from this time evinced by the male fish. He kept constant watch over the nest, every now and then shaking up the materials and dragging out the eggs, and then pushing them into their receptacle again, and tucking them up with his snout, arranging the whole to his mind, and again and again adjusting it tili he was satisfied; after which he hung or hovered over the surface of the nest, his head close to the orifice, the body inclined upwards at an angle of about 45°, fanning it with the pectoral fins, aided by a side-motion of the tail. This curious manceuvre was apparently for the purpose of ventilating the spawn; at least by this means a current of water was made to set in towards the nest, as was evident by the agitation of particles of matter attached to it. This fanning or ventilation was frequently repeated every day till the young were hatched; and sometimes the fish would dive head foremost into his nursery and bring out a mouthful of sand, which he would earry for some distance and discharge with a puff, At the end of a month the young ones were first perceived. The nest was built on the 28rd of April, the young appeared first on May 21. Unremitting as had been the attention of this exemplary parent up to the time of the hatching of the eggs, he now redoubled his assiduity. He never left the spot either by day or night; and during the daytime he guarded it most pertinaciously, allowing nothing to approach. ... The fry were at first so minute and transparent that they were scarcely perceptible, and it was only by a slight fluttering motion their position could be occasionally discovered; otherwise it was impossible to detect them.” Although the name of pipe-fishes is frequently applied to the members of the second family of the group under consideration, it is better to restrict that term to the Syngnathide (described in the sequel), and take that of flute-mouths for those to be now noticed. As a family, the flute- mouths are readily distinguished from the sticklebacks by the production of the bones of the muzzle into a long tube, terminated by a small mouth: and likewise Flute-Mouths. 406 SPINY-FINNED GROUP. by the pelvic fins consisting of six soft rays. The greatly elongated body is either covered with very small scales, or naked; the teeth are small; the first dorsal, if present, is formed of small isolated spines ; the soft dorsal and anal are of moderate length; the pelvic fins consist of six rays, without any spine, and are separated from the pubic bones, which remain attached to the pectoral arch; and there are five branchiostegal rays. The air-bladder is large, and the vertebrae are very numerous, those in the anterior part of the column being fused into a continuous tube, as in the flying gurnards. These fishes, which may be regarded as gigantic and highly specialised marine sticklebacks, frequent the coasts of the tropical and subtropical portions of the Atlantic, Indian, and Pacific Oceans, some of them growing to from 4 to 6 feet in length. In the genus Fistularia, the body is naked, the forked caudal fin has one or two of its middle rays produced into a long, whip-like filament, and there are no isolated spines to the dorsal fin. The species are confined to the Tropical Atlantic and Indian Oceans. On the other hand, in the typical genus Aulostoma the body is covered with small scales, the caudal fin squared, and without filaments, while the back carries a series of small isolated spines, and the teeth are rudimentary. In this genus the species inhabit the Atlantic; but the third genus (Auliscops) is represented by a single form from the North American Pacific coast, distinguished by the naked body, the thoracic position of the pelvic fins, and the presence of numerous spines in front of the dorsal fin. Day states that he found the Indian species of Fistulariva, which is common at Madras, frequenting the most muddy localities. Trumpet-Fishes, While agreeing with the flute-mouths in the production of the ete. muzzle into a tubular beak, the two genera of fishes constituting the family Centriscide differ by the imperfect development of the pelvic fins, which are truly abdominal in position. They have two dorsal fins, of which the spinous one is short, while the soft one is similar to the anal. Teeth are wanting. The family is distributed over the Atlantic, Mediterranean, and Indo - Pacific, the common trumpet or bellows fish (Centriscus scolopax) occasionally making’ its appearance on the south coast of England, while it is also known from such a distant region as Tasmania. It belongs to a genus characterised by the oblong or elevated and compressed body being covered by small rough scales, with some bony strips on the back and under surface, the absence of a lateral line, and the length of the spines of the first dorsal fin. The second genus, Amphisile, differs by the elongate form of the compressed body, which is covered on the back with a cuirass of bony plates, behind which are the two dorsal fins. This genus is confined to the Indo-Pacific; and in the Indian A. scwtatw the dorsal armour terminates behind in a long spine, close beneath which are the three spines of the first dorsal fin, followed by the second dorsal, the caudal appearing on the lower surface of the body just behind the anal. Dr. Giinther writes that in these tortoise-fishes, as they may be called, the “body is so thin that it has the appear- ance of being artificially compressed between two sheets of paper; it is semi- transparent, especially in the region of the air-bladder. The structure of the vertebral column is extremely singular, and unique among Acanthopterygians. The trunk portion is more than four times as long as the caudal, nevertheless it is composed of only six vertebr, whilst the latter consists of fourteen.” The SUCKER-FISHES. 407 trunk vertebrxe are extremely slender, the third alone being nearly as long as the whole caudal portion; while in the latter all the vertebree are very short. In a fossil state the tortoise-fishes are represented in the middle Eocene of Monte Bolea : and it may be mentioned here that in the preceding family the genera Fistularia and Awlostoma occur not only in those deposits, but likewise in the lower Eocene of Switzerland; and Auliscops has been recorded from the Eocene of Sumatra, and two extinct generic types have been described from the Monte Bolea beds. THE SUCKER-FISHES,—Family GOBIOESOCID. The small fish (Lepadogaster bimaculatus), of which three examples are shown in the annexed illustration, is one of three British representatives of a genus belonging to a small family which constitutes a sectional group by itself. Long TWO-SPOTTED SUCKER-FISH (nat. size). confounded with the lump-suckers, which they resemble in having an adhesive dise on the under surface of the body, the sucker-fish differ from that group, not only in the structure of that disc, but likewise in several other respects. They have no spinous dorsal fin; the soft dorsal and anal are short or of medium length, and situated far back, at the root of the tail; the pelvic fins are almost jugal in position, and have the adhesive dise placed between them; while the body is covered with a naked skin. Whereas in the lump-suckers the pelvic fins are close together, and actually form the base of the sucking disc, in the present family they are widely separated from each other, and only enter into the composition of a portion of the margin of the adhesive apparatus, which is completed by a cartilaginous expansion of the bones of the pectoral girdle. In size the ovoid dise is relatively large, its length being sometimes as much as one-third that of the whole fish, and it is divided into an anterior and a posterior moiety, of which the second may or may not have a free front margin. All these fishes are littoral forms of small size, ranging over both temperate zones, where they are more 408 SPINY-FINNED GROUP. numerous than in the tropics. Among the numerous genera we can only mention the typical Gobioesox, from the West Indies and Pacific coast of South America, distinguished by the absence of a front free margin to the posterior division of the sucker, and the presence of incisor-like teeth at least i the lower jaw; and the European Lepadogaster, in which the hinder-half of the sucker has an anterior free margin, and the teeth are small and fine. The British species, although variable in this respect, are very prettily coloured; the figured one being generally carmine-red above, and pale flesh-colour below, with a light patch between the eyes, and two more or less distinct spots on the sides. It has been obtained adhering to stones and shells in deep water off Torquay. Montagu writes that when placed in a vessel of sea-water these little fish “always adhered to the sides of the glass by the apparatus termed the sucker, and frequently remain fixed till they died; and even after death the power of adhesion continues. The wet finger being applied to the part, the fish becomes suspended; when alive, they instantly attach themselves to the hand if taken out of the water.” THE SERPENT-HEADS,—Family OPHIOCEPHALIDZ. Mainly characteristic of the Oriental region, although also represented in Africa, the fresh-water fishes known as serpent-heads are interesting not only on account of their structure, but likewise from their peculiar habits. They form a single family, constituting a sectional group by itself, and represented by two genera, in one of which (Ophiocephalus) pelvic fins are present, while in the second (Channa) they are wanting. As a family, the serpent-heads are character- ised as follows. ‘The body is elongate and covered with medium-sized scales; all the fins are devoid of spines, the anal and single dorsal being*long and low ; and there is an additional cavity above the proper gill-chamber, although this is not furnished with supplemental gills. The depressed head is covered with somewhat plate-like scales, and has the eyes lateral and the gill-openings wide; each gill- chamber containing four gills, while teeth are present on the jaws, palatines, and vomer. If present, the pelvic fins are thoracic in position, and composed of six rays. The lateral line is sharply curved or almost interrupted, and an air-bladder is present. Of the typical genus there are some thirty existing species, having a distribution coextensive with that of the family, and in Asia ranging over Baluchistan, Afghanistan, India, Ceylon, Burma, China, Siam, and the Malay Archipelago; the figured species (0. striatus) being common to such distant localities as India and the Philippines, and at times reaching as much as a yard in length. The second genus, Channa, is represented only by a single species from Ceylon and China. In a fossil state these fishes have been identified from the Phocene rocks of the Siwalik Hills in North-Eastern India. In India the serpent-heads are found both in rivers, ponds, tanks, and swamps, many of them seeming to prefer stagnant to running waters. Day writes that these fishes “having hollow cavities in their heads, and an amphibious mode of respiration, are able to exist for lengthened periods out of their native element, and can travel some distance over the ground, especially when it is moist. They are able to progress in a serpentine manner, chiefly by means of their pectoral SERPENT-HEADS. 409 and caudal fins, first one of the former being advanced and then the other. These fishes appear to be monogamous, some breeding in grassy swamps or the edges of tanks, some in wells or stone-margined receptacles for water, and others again in holes in river-banks. The varieties which live in tanks and swamps keep much to the shallow and grassy edges. Amongst the fish which I myself saw exhumed from the mud of a dried-up tank were some Ophiocephali; they are also recorded by the natives of India as descending with downpours of rain.” When living in muddy water they rise to the surface from time to time to take in atmospheric air, and captive examples prevented from doing this have been known to die. STRIATED SERPENT-HEAD (} nat. size). During the time they are buried in hard mud it must be assumed that these fish become completely torpid and stop the respiratory function. THE LABYRINTH-GILLED FISHES,—Families AVABANTID& and LUCIOCEPHALID.. In the members of these two families of estuarine and fresh-water fishes, which constitute a sectional group by themselves, the apparatus for enabling them to exist for a considerable time out of the water is carried to a greater degree of complexity than in the last, and takes the form of a laminated accessory gill-like organ, situated in a chamber on each side of the head above the one containing the true gills. In these fishes the body is compressed, oblong, and elevated, with medium-sized ctenoid scales. The eyes are lateral, the gills four in number, the gill-opening rather narrow; and false gills either rudimentary or wanting. The single dorsal fin, as well as the anal, has a variable number of spines; and the pelvic fins are thoracic in position. While in some cases the lateral line is interrupted, in others it is altogether wanting; and the air-bladder may be either present or absent, but when developed it is generally very large, sometimes even extending into the tail. These fishes, which are of comparatively small size, are confined to Southern Asia and South Africa, and are all capable of existing for a longer or shorter period out of their native element, when they oxygenate their blood directly from atmospheric air by means of the accessory 410 SPINY-FINNED GROUF. gill-like organ. Whereas some are carnivorous, others are vegetable-feeders ; but all are capable of domestication, in which state they are subject to considerable variation, and several have been acclimatised in countries other than their own. The flesh of all of them is said to be eatable, and that of some is of excellent quality. On account of their brilliant coloration, and the curious habits of some of them, these fish have always attracted more than ordinary interest. The fish to which the somewhat inappropriate name of climbing- Climbing-Perch. o 5 perch (Anabas scandens) has long been applied by Europeans in CLIMBING-PERCH ON LAND (3 nat. size). India is the sole representative of a genus characterised by the presence of teeth on the palate, and the serration of the free margins of the opercular and preorbital bones. In form the body is compressed and oblong; the lateral line is interrupted ; the single dorsal fin has its spinous portion much longer than the soft part; while in the anal fin the spines are less numerous than those on the back. The caudal fin is rounded, and the seales are rather large. In length the climbing-perch may reach at least 84 inches, and in the adult state its general colour is dark green, usually marked with dusky bands, which disappear soon after death. It frequents. PARADISE-FISH. ATI both estuaries, rivers, and tanks, and is distributed over India, Ceylon, Burma, the Malay Archipelago, and the Philippine Islands. That this fish can travel long distances on land, where it drags itself along by hitching its pectoral fins round the stems of grass and other herbage, in the manner indicated in our illustration, is perfectly well ascertained. With regard to its climbing powers some amount of incredulity has been expressed, but it is very noteworthy that its Malayan name (wndi-collz) signifies tree-climber, while nearly a thousand years ago certain Arab travellers were informed of the existence in India of a fish that was in the habit of ascending cocoa-nut palms to drink their milk. Apparently the only definite record that we have of a European having witnessed such scansorial feats is from the pen of one Daldorf, who wrote that in the year 1791 he had taken one of these fishes from a moist cavity in the stem of a palmyra- palm growing near a lake. He first observed it when already five feet from the ground, struggling to ascend higher, and suspending itself by its gill-covers; and bending its tail to the left, it fixed its anal fin in the cavities of the bark, and sought by expanding its body to urge its way upwards, and its march was only arrested by the hand with which he seized it. Although there is no reason to doubt this very detailed narrative, the circumstance that later observers in India have never seen the feat repeated would seem to indicate that it is but seldom the fish takes to actual climbing. Regarding the habit of this fish, in common with the serpent-heads, of burying itself in the mud of tanks, Sir J. E. Tennent writes that “in those portions of Ceylon where the country is flat, and small tanks are extremely numerous, the natives are accustomed, in the hot season, to dig in the mud for fish. Mr. Whiting informs me that, on two occasions, he was present accidentally when the villagers were so engaged, once at the tank of Malliativoe, within a few miles of Kottiar, near Trincomali, and again at a tank on the Vergel River. The clay was firm but moist, and as the men flung out lumps of it with a spade, it fell to pieces, disclosing fish from 9 to 12 inches long, which were full- grown and healthy, and jumped on the bank when exposed to the sunlight.” The Oriental region is the home of another allied genus of fishes (Polyacanthus), represented by several species, and differing from the climbing perch by the absence of teeth on the palate, and the smooth margins of the preorbital and opercular bones; the mouth being small and slightly pro- tractile. The spinous part of the single dorsal fin is much longer than the soft portion, the anal being similar; the pelvic fins have one spine and five soft rays, some of which are usually elongated; and the caudal is rounded or pointed. The lateral line, which is never complete, may be wanting. These fishes inhabit fresh Paradise-Fish. waters and estuaries along the coast of South-Eastern Asia, but are seldom found any great distance inland. The pretty and brightly coloured paradisc-fish is an inhabitant of China and Cochin-China, and was long regarded as the representative of a distinct genus. It is, however, now known to be merely a domesticated variety of a species of Polyacanthus, although we are not aware that the normal form has hitherto been discovered. From our figure it will be seen that it differs from the ordinary members of the genus in the large and forked tail, and likewise in the great development of the soft rays of the dorsal and anal fins. Throughout China this fish is kept in confinement; and is even more suited to 412 SEIN -PLINN EDGR OCT. captivity than the gold-fish, as it will breed in vessels of very sinall capacity. It is even stated to live in water strongly impregnated with acid, and its tenacity of life is very great. When kept in dark or muddy waters the colour is generally a dull uniform brown; and it is only when living in clear water, exposed to the sunlight, that the golden hue and red transverse bands make their appearance, these showing at an earlier period in the males than in the females. On account of the excellent quality and taste of its flesh, mention must be made here of the gurami (Osphromenus olfax), as a well- known representative of a third genus belonging to this family. Agreeing with the members of the preceding genus in the absence of teeth on the palate, the smooth border to the preorbital and opercular, and the structure of the pelvic fins, Gurami. PARADISE-FISH AND TELESCOPE-FISH. these fishes differ by the smaller number of spines in the dorsal or anal fins, which are either fewer than the soft rays, or but very slightly exceed them. The body is moderately elevated and compressed ; the small and oblique mouth is capable of a considerable degree of protrusion ; and the first ray of the pelvic fins is elongated into a slender filament, the remainder being generally rudimentary. When present, the lateral line is continuous; and there is always an air-bladder. Distributed over the rivers of South-Eastern Asia, these fishes are represented in India only by a small species (O. nobilis), of some 4 inches in length, inhabiting North- Eastern Bengal and Assam. The gurami, which is a native of the rivers of China and the Malayan Archipelago, has, however, been introduced into several parts of India and has also been naturalised in the Mauritius, Cayenne, and Australia. It is easily recognised by its large size, great convexity of the profile of the under surface, and greenish brown colour, marked in the immature condition by four or FIGHTING-FISH Are o five dark vertical bands. It attains a weight of fully 20 lbs. and, when kept in clean water, is stated to be the best flavoured fresh-water fish in South-Eastern Asia. As it is extremely tenacious of life, and likewise almost omnivorous in its diet, it is in every way admirably adapted for transportation and acclimatisation. THE GURAMI (;4 nat. size). A fourth genus (etta), distinguished by the short dorsal fin occupying the middle of the back, and without any pungent spine, the long anal, and the production of the outer ray of the five-rayed pelvic fins, must also be mentioned on account of its containing the so-called fighting-fish (B. pugnax), which is bred by the Siamese for the sake of the sport afforded by its pugnacious propensities. Cantor writes that, “when the fish is in a state of quiet, its dull colours present nothing remarkable; but if two be brought together, or if one sees its own image in a looking-glass, the little creature becomes suddenly excited, the raised fin and the whole body shine with metallic colours of dazzling beauty, while the projected gill-membrane, waving like a black frill round the throat, adds something of grotesqueness to the general appearance. In this state it makes repeated darts at its real or reflected antagonist. But both, when taken out of each other’s sight, become instantly quiet. This deseription was drawn up in 1840 at Singapore, by a gentleman who had been presented with several by the King of Siam. They were kept in glasses of water, fed with larvae of mosquitoes, and had thus lived for many months. The Siamese are as infatuated with the combats of these fish as the Malays are with their cock-fights, staking on the issue considerable sums, and sometimes their own persons and families. The licence to Fighting-Fish, exhibit fish-fights is farmed, and brings a considerable annual revenue to the King of Siam. The species abounds in the rivulets at the foot of the hills of Penang.” 414 SPINY-FINNED GROUEF. The small fish (Luciocephalus pulcher), from the fresh waters of the Malay Archipelago, shown in the accompanying illustration, is the sole representative of the second family of the labyrinth-gilled group, which difters from the first in the absence of spines from both the dorsal and anal fins. Pike-Head. The species derives its name from the produced muzzle and general pike-like form of the head; and has its elongate body covered with moderate-sized scales, and traversed by a continuous lateral line. The teeth are small, and the gill-openings wide. The single spineless dorsal fin is very short and placed far back on the body; the pelvics consist of one spine and five rays, one of the latter being PIKE-HEAD (nat, size). elongated ; and the tail-fin is rounded. There is no air-bladder. Nothing is known with regard to the life-history of this prettily marked fish. Unicorn AND Rippon-FisH,—Families LOPHOTIDA and TRACHYPTERIDA. Avreeing in their ribbon-shaped bodies, and also in the extension of the dorsal fin from the head to the end of the tail, the unicorn and ribbon-fishes are thereby easily distinguished from all the preceding forms, although they differ so much from one another as to be entitled to form distinct families, each of which is regarded by Dr. Giinther as representing a sectional group. pene The single representative of the first family (Lophotes cepedianus) differs from the whole of the members of the subclass hitherto described, in that the vent is situated at the hinder extremity of the body, close to the tail, with a small anal fin immediately behind it. The pelvic fins are very minute, and thoracic in position; the caudal is also small and rounded; the mouth is incapable of protrusion; teeth are present on the jaws, palatines, and vomers; and there is an air-bladder. The most striking peculiarity about this strange fish is the eleva- tion of the crown of the head into a high crest, surmounted by an exceedingly long and recurved spine forming the commencement of the dorsal fin. The bones and flesh are firm, the general colour is silvery, with lighter spots, but the fins are rosy ; and the total length is at least 5 feet. This fish, which has been taken in the Atlantic off Madeira, and also in the Sea of Japan, probably dwells at a consider- able depth, although not so far down as the ribbon-fishes. Its habits are unknown. RIBBON-FISH. 413 From the unicorn-fish the members of this family may be distinguished by the absence of an anal fin, and by the caudal (which, as in our figure, is rarely preserved in the adult state) being either rudimental, or small and bent up above the axis of the body in a fan-like manner. The band-lke body, which may measure as much as 15 or 20 feet in length, with a depth of a foot and a breadth of not more than an inch, terminates in a short and deep head, furnished with large lateral eyes, and a small mouth; the teeth being feebly developed. The high dorsal fin is composed of a very numerous series of rays, which are neither articulated nor branched, and has a detached Ribbon-Fishes. UNICORN-FISH (745 nat. size), portion on the crown of the head elevated into tall filaments,’ and the thoracically- placed pelvic fins may consist either of several rays, or be reduced to a single long filament. Scales are wanting; and the numerous vertebr as well as the other bones, are remarkable for their softness and loose structure; the flesh being like- wise of a flabby consistence. The young, which are not unfrequently found at the surface of the ocean, are very unlike the adults, having the body more like that of an ordinary fish, but remarkable for the enormous development of the rays of the front part of the dorsal and pelvic fins, and in a minor degree those of the caudal likewise. The dorsal rays are, indeed, several times the length of the whole fish, and are furnished at intervals with barb-like dilatations. Most ribbon- fish are silvery in colour, with rosy fins. They are divided into three genera, of 1Tn our figure this part is represented as connected with the rest of the fin, 416 SPIN VHNNED GROCEL. which LTrachypterus has well-developed pectoral fins, while Stylophorus has the tail produced into an exceedingly long filament; Regalecus being distinguished by the reduction of the pelvic fins to a pair of long filaments with dilated extremities, and the small size or rudimentary condition of the caudal. Our figured example (R. banksz) belongs to the third genus, and has the body of considerable relative depth, but ina much smaller Indian form (RA. russelli) the body is so slender as to have a rod-like appearance. Banks's ribbon-tish appears to be only known from specimens cast ashore on the British coast; the first of these having been stranded at Whitby in January 1759, since which date only fifteen other examples were BANKS’S RIBBON-FISH (7g nat. size). recorded up to 1878. All these fishes are, indeed, known almost entirely from examples found in a dead or dying condition on the surface of the ocean, or cast ashore by the waves. In this state the whole of their tissues are so disintegrated and broken that the body can scarcely be lifted whole from the water, and it is thus evident that ribbon-fishes are inhabitants of the lower strata of the ocean. although at what precise level they live has not yet been ascertained. They are found in all seas, but are mostly of very rare occurrence on the surface, the single representative of the genus Stylophorus being only known by one example captured in the early part of this century near Cuba; while the same is the case with regard to Russell’s ribbon-fish from Madras. That the young are also deep- THORNBACKS. 417 sea fishes is, as Dr. Giinther remarks, perfectly evident from their filamentous fins, which would be irretrievably damaged if their owners did not live at depths where the water is perfectly undisturbed. From the expansion of the extremities of the pelvic fins, Banks’s ribbon-fish has been named the oar-fish; while from a supposed idea that it accompanied the shoals of those fish, it has likewise been designated the king of the herrings. It has been suggested that large ribbon-fish floating on the surface have given rise to many of the reports regarding the sea- serpent; but, as Dr. Giinther pertinently points out, such dead or dying creatures do not by any means accord with the active movements generally attributed to that mythical monster. Still, however, we believe that a stranded ribbon-fish has been mistaken for a dead sea-serpent. THE THORNBACKS,—Family NOTACANTHID. The last family of the great division of spiny-finned fishes we have been considering in the foregoing paragraphs includes only the deep-sea fishes NA ew URS WOON ° YOON RRO RISSO’S THORNBACK (4 nat. size). . known as thornbacks, all of which are referred to the single genus Notacanthus. These fishes are very abnormal forms, agreeing only with the more typical members of the suborder to which they are referred in the presence of spines in the median fins. Possessing an elongate and somewhat compressed body, covered with minute scales, they are specially characterised by having the dorsal fin composed of a series of low isolated spines, without any soft portion; while the anal is elongated, with a great number of spines; the pelvic fins being abdominal in position, and comprising more than five soft rays, in addition to several un- articulated ones. In the head the muzzle is prolonged in advance of the mouth; the moderate-sized eyes are lateral in position; and the teeth are small and weak. The six known species range from the Arctic Ocean to the Mediterranean, Atlantic, and South Pacific. All are deep-sea fishes, probably dwelling at depths of from a hundred to five hundred fathoms ; although one specimen taken to the south of Yokohama during the voyage of the Challenger is stated to have come from a depth of nearly nineteen hundred fathoms. VOL. V.—27 418 SPINY-FINNED GROUP. THe WRASSE-LIKE FisHEes,—Families POMACENTRIDA, LABRIDA, CHROMIDIDA, ete. In almost all the families of spiny-finned fishes hitherto described the lower pharyngeal bones are completely separated from one another, whereas in the four families remaining for consideration these are united with one another. It has been considered that this difference was of sufficient importance to justify the reference of the families with united pharyngeals to a subordinal group of equal rank with one containing those in which these bones remain distinet ; but we prefer to follow Day in regarding the group now to be considered merely as a section of the suborder which includes all the other spiny-finned fishes. That this is the correct view is proved by the circumstance that in one aberrant genus of perches SILVER-DOTTED POMACENTRUS (§ nat. size). (Gerres) some of the species have the lower pharyngeal bones separate, while in others they are united. In the three families constituting the present group there is a single dorsal fin, in which the number of spines and soft rays 1s nearly equal; while the anal is usually similar in character to the soft dorsal ; and the pelvic fins are thoracic in position, and include one spine and five soft rays. . The first of the families of the present sectional group takes its name from the genus Pomacentrus, which, together with the allied genera, includes tropical fishes mainly frequenting the neighbourhood of coral- reefs and islands, and thus closely resembling the scaly-finned fishes (p. 343) in their mode of life; a few species of the family range, however, into the seas of the temperate zones. As an example of the typical genus, we figure P. scolopsis, from the Malayan seas and Polynesia. As a family, these fishes are specially characterised by the presence of false gills and etenoid scales. In form, the body Pomacentrus. WRASSES. 419 is more or less short and compressed; there are weak teeth in the jaws but none on the palate, and there is an air-bladder, The family is represented by eight genera and considerably over a hundred species; and the genera may be divided into groups, according as to whether all or some of the opercular bones are serrated at the edges or are all simple ; Pomacentrus belonging to the intermediate group, in which the preopercular is serrated, while the edges of the other bones of the gill-cover are entire. In a fossil state the family is represented by an extinct genus from the middle Eocene deposits of Monte Bolea. Pomacentrus is the largest genus of the family, its representatives ranging over the tropical seas of both hemispheres. Curiously enough, not only do these fishes resemble the scaly-finned fishes in their mode of life, but they are very similarly coloured, so much so, indeed, that in some instances actually the same pattern of coloration is common to members of the two famihes. This, as remarked by Dr. Giinther, is one of many instances showing that the coloration of animals depends to a great extent on their mode of life and natural surroundings. All these fishes are carnivorous, subsisting on various small marine animals; those furnished with compressed teeth probably browsing on the coral-polyps. Distinguished from the preceding family by their cycloid scales, the wrasses form an extensive group (Labrida), many of the members of which may be easily recognised by their greatly thickened lips, sometimes provided with an internal fold; and from this character they derive their German title of lip-fishes. False gills are present, and the true gills, three and a half in number on each side. The body is oblong or elongate, and while teeth are present in the jaws they are absent on the palate. In the single dorsal fin the number of spines is usually equal to that of the rays; the anal is similar to the soft dorsal, and an air-bladder is present. Littoral in their habits, the great majority of the wrasses are found in tropical and temperate seas, none occurring within the limits of the polar seas. Rocks and coral-reefs are their favourite haunts, most of them feeding chiefly on molluscs and crustaceans, for crushing the shells of which their teeth are specially adapted. In many kinds there is an additional pointed curved tooth at each angle of the upper jaw, used for holding a shell against the front and side teeth, by which it is crushed. The majority of the wrasses are beautifully coloured fishes, decorated not only with transient iridescent hues on the scales, but likewise with permanent colours formed by the deposition of pigment in the tissues. Some of the species grow to a large size, specimens weighing upwards of 50 Ibs.; and it is these larger species which are most esteemed as food-fishes, the flesh of the smaller kinds being of inferior quality. In a fossil state wrasses date from the middle Eocene of Monte Bolea, where remains referable to the existing genus Labrus occur; while an extinct Eocene genus from North America appears to be the ancestral form of the existing black fish (Zawtoga). An allied extinct family is represented by Phyllodus, from the Cretaceous and lower Eocene of Europe—distinguished by the flattened leaf-like pharyngeal teeth—as well as Wrasses. by several other more or less nearly related Tertiary types. < Asit would be quite impossible in our limited space to describe True Wrasses. 7 o J even a few of the numerous genera of wrasses, we must content ourselves with saying that these are arranged in groups according to the structure 420 SPIN VFINNED GROOP. of the anterior teeth, and devote our remaining observations mainly to the typical wrasses constituting the genus Labrus. In this genus, of which the figured striped or red wrasse (L. mixtus) may be taken as a well-known British example, the body is compressed and oblong in form, with the moderate-sized scales arranged in more than forty transverse rows; the muzzle is more or less sharply pointed; the cheeks and opercular bones are covered with imbricating scales, which are, however, wanting or but few in number on the interopercular; and the conical teeth are arranged in a single row in the jaws. ‘The spines of the dorsal fin are numerous, varying from thirteen to twenty-one, and are all of approximately equal height ; there are three spines in the anal fin; and the lateral line is continuous. In the young, the edge of the preopercular bone is serrated. ‘These wrasses are chiefly STRIPED WRASSE (4 nat. size), characteristic of the Mediterranean area, gradually diminishing in the more northern seas of Europe, and being quite unknown in those of India. The striped wrasse exhibits a remarkable sexual variation of colour; the males usually having the body marked with blue streaks or a blackish band, while in the females the back of the tail shows two or three blackish blotches. The other British species is the Ballan wrasse (Z. maculatus), in which the general colour is bluish green, the seales being margined with reddish orange, and the fin-rays also of the latter tint. Couch writes that the Ballan wrasse “frequents deep gullies among rocks, where it shelters itself among the larger kinds of seaweeds, and feeds on crabs and other crustaceous animals. It takes a bait freely, and fishermen remark that when they first fish in the place they take but few, and those of large size; but on trying the same spot a few days after, they catch a great number, and those WRASSES. yee smaller, from which they conclude that the large fish assume the dominion of a district, and keep the younger at a distance.” The gold sinny (Crenilabrus melops) is a British example of a second genus, distinguished by the serrated edge of the preopercular, Another well-known member of the family is the black-fish (Tautoga onitis), of the Atlantic coast of North America, so named on account of its blackish brown colour, and the sole representative of a genus characterised by the naked opercular, the rudimental scales on the cheek, and the double row of teeth in the jaws. Since their Mediterranean representative (Scarus cretensis) was a fish held in high estimation among the ancients, brief mention must be made of the parrot-wrasses, of which the other species are inhabitants of the tropical parts of the Atlantic. These fishes are easily recognised by their sharp Parrot-Wrasses. \ \ iy \ \ Ay Vey) aN K LOIN ANY \ i) Nt hy, ) YY RAN ee i Nt AN se the true eels, and the head is scaleless and without barbels. The dorsal fin is either totally wanting, or reduced to a fatty rudiment; the anal is extremely elongated; pelvics are wanting; and the caudal is likewise generally absent, the oD = >] DS ; . tail terminating in a point, which, when broken off, can be renewed in the same manner as in the blind-worms. The vent is situated in or near the throat ; the gill-openings are rather narrow; an air-bladder is present; the stomach has a blind appendage; and the ovaries are provided with puck In the skeleton the pectoral girdle is attached to the skull. By Professor Cope the typical genus 1s 5 5 . . . considered to be to a certain extent intermediate between the last family and the eel-like representatives of the cat-fishes. 452 TUBE-BLADDERED GROUF. As a genus, the electric eel is characterised by the absence of the caudal and dorsal fins, by the anal extending to the extremity of the tail, the absence of scales, the single series of conical tecth, and the minute eyes. Abundant in the rivers and lagoons of certain parts of Brazil and the Guianas, the electric eel grows to a length of fully 6 feet, and is capable of giving a more powerful shock than any of the other fishes endued with electric power. It will be unnecessary to give any deseription of the electric organs here; and it will accordingly suffice to mention that they form two pairs of longitudinal structures lying between the skin and the muscles; one pair being situated on the back of the tail, and the other along the sides of the base of the anal fin. That these organs are capable of giving shocks sufficient to kill other fish and small manuals is undoubted; but Dr. Giinther considers that the description by Humboldt of the capture of electric eels by horses driven into water, in order to receive the shocks and thus exhaust the fishes, seems to be the result of the imagination of some person who related the supposed incident, or to rest on some isolated incident, since no recent travellers to the district have found evidence of the existence of the practice. SECTION NEMATOGNATHI. THE CaT-FISHES OR SHEATH-FISHES,—Family SIZURIDZ. Although represented only by a single European species, and that confined to the rivers to the eastward of the Rhine, the great family of cat-fishes is one of extreme importance in tropical and subtropical countries, its members being extremely abundant in the fresh waters and estuarses of the Oriental region, as they are in those of South America. An essential characteristic of the family is the invari- able absence of scales, the skin being either smooth or covered with bony tubercles or plates; and this character, together with the presence of the barbels from which they derive their popular title, will always serve to distinguish the cat-fishes from the other great fresh-water family of the carps. In the skull an essential feature is the absence of a subopercular element to the gill-cover; while the margin of the upper jaw is formed mainly by the premaxille, the maxille being more or less rudimental. A rayed dorsal fin may be absent, but the fatty dorsal is generally present; and when an air-bladder is developed, it may be either free in the abdominal cavity or enclosed in bone, but always communicates with the ear by the intervention of the auditory ossicles, which are somewhat lenticular in form. The skull is characterised by the full ossification of its lateral region, the septum between the eyes being also bony; and in many instances the skull is prolonged backwards by the development of a kind of bony helmet over the nape of the neck, formed by dermal ossifications overlying some of the bones of the pectoral girdle. Frequently this shield, as well as the hinder bones of the skull, are ornamented with a tuberculated sculpture. Many of these fishes have also a powerful spine at the front of the dorsal fin, which can be locked into a fixed, erect position by a rudimental spine acting asa kind of bolt at its base, and is itself articulated to the vertebre, and also joined by a ring to a second spine, in a manner similar to that obtaining in the angler-fish. To support this spine certain special modifications exist in the structure of the pectoral girdle. Some of the genera, CAT-FISHES. 453 such as the one represented by the eel-like cat-fish, have additional breathing- organs ; in this particular instance taking the form of a branched structure attached to the gills. On the other hand, in the sac-gilled cat-fishes (Saccobranchus), there is a long sac running down the muscles of the back behind the proper gill-chamber. Through this breathing-sac blood is carried from and returned directly to the heart; and in consequence of this arrangement these fishes can remain alive for hours or even days apart from water, so that they are able to traverse spaces where aquatic respiration is impracticable. Among the Indian representatives of the family it is somewhat curious that whereas most of the forms dwelling far in the interior of the country near and in the hills have the air-bladder ossified, this is not the case with those inhabiting the rivers of the plains and the sea. The majority of the cat-fishes are inhabitants of the fresh waters and estuaries of the tropical and subtropical regions of the globe ; but, as we have seen, one species is found in those of Eastern Europe, while a considerable number enter the sea, although generally keeping near the coasts. They are found not only in rivers, but likewise in lagoons and marshes. Day writes that “they mostly prefer muddy to clear water, and the more developed the barbels the more these fishes appear to be adapted for an inland or muddy fresh-water residence. The wider and deeper the rivers, the more suited they are for the Si/uride, consequently the larger forms are comparatively rare in the south of India, whilst they abound in the Indus, Jumna, and Ganges, as also in the Irawadi and other Burmese rivers.” It may be added that they are equally common in the muddy waters of the La Plata River. “Owing to their usual resort,” continues the same writer, “these fishes appear to employ their feelers in moving about in muddy places, and consequently have less use for their eyes than forms that reside in clear pieces of water. This is one reason why the size of the eye as compared with the length of the head is much greater in the young than in the adult. The eye, in fact, atrophies, instead of increasing in size in proportion with the remainder of the head. In some species the skin of the head passes over the eye without any trace of a free orbital margin. In the genus Arius, and some allied marine forms, the males appear to carry their ova in their mouths, perhaps until the young are produced. Many of these fishes are credited with causing poisonous wounds, and we frequently find such cases admitted into hospitals. The injuries may be divided into two classes, namely, those in which the wounds are of a distinctly venomous description, and those in which the jagged spines occasion intense inflammation, often of a dangerous character.” The flesh of the cat-fishes is of an inferior quality, and generally eaten only by the lower classes. All the members of the family are very tenacious of life, and extremely difficult to kill, Geologically cat-fishes date from the lower Eocene London Clay, where they are represented by the extinct Bucklandium, apparently allied to an existing African genus; while in the higher Eocene of the south of England there occur species referred to the existing genus Arius. An extinct genus has also been described from the Eocene of North America; and in the Eocene of Sumatra, as well as in the Pliocene of India, the fossil forms belong to existing genera, and some of those from the latter deposits even to species still inhabiting the same country. Numerically the eat-fishes form an exceedingly large family, the existing types constituting considerably over a hundred genera, 454 TUBE-BLADDERED GROUP. many of which contain a multitude of species. In this work only a very few of the genera can be even mentioned, some of those selected including the largest members of the family. Claurias anguillaris is a well-known representative of the first subfamily, in which the long dorsal and anal fins extend nearly throughout the length of the trunk, It belongs to a minor group confined to Africa and the Oriental region, and characterised by the dorsal fin being either Eel-Like Cat-Fish. composed of weak rays throughout its length, or with its hinder portion modified into a fatty fin. The wels (Silwrus glanis), shown in the larger figure of the illustration on p. 436, is the typical representative of the second subfamily, in which the rayed dorsal fin is but little developed, and if present at Wels. all occupies only the hinder region of the trunk; the fatty portion being small or wanting. The anal fin is not much shorter than the caudal region of the backbone, and the pelvic fins are behind or below the dorsal. In the wels and its congeners the short dorsal has no pungent spine ; the fatty fin is wanting; there are two upper and two or four lower barbels; the head and body are naked; and the tail-fin is rounded. The wels itself, which is confined to the European rivers eastwards of the Rhine, has six barbels, of which the upper pair are considerably longer than the head, and commonly attains a length of from 6 to 9 feet, although it occasionally grows to 13 feet. In colour the head, back, and edges of the fins are bluish black, the sides greenish black spotted with olive-green, and the under-parts reddish or yellowish white with blackish marblings. Frequenting rivers and lakes with muddy bottoms, the wels feed on fishes, frogs, and crustaceans, but it will also seize and pull down ducks, geese, or other birds swimming on the surface. The spawning- time is in the middle of summer, when these fish resort to the shallows in order to deposit their eggs on the stems and leaves of water-plants. Yarrell’s Cat- Another gigantic species is Yarrell’s cat-fish (Bagarius yarrell2), Fish, etc. from the large rivers and estuaries of India and Java, which attains a length of fully 6 feet, and from its huge head and mouth is one of the ugliest fishes in existence. The only member of its genus, it belongs to a subfamily in which the rayed dorsal fin is short, and situated in the hinder part of the body in advance of the pelvics; and there is always a fatty fin, which may, however, be short; and the anal is shorter than the caudal region of the backbone. When nasal barbels are developed, they belong to the hinder nostrils. In the group of genera to which Yarrell’s cat-fish belongs the front and hinder nostrils are placed near together, with a barbel between them; and in this particular form there are eight barbels, and the upper surface of the head is naked. This gigantic species is of especial interest on account of its fossilised remains occurring in the Pliocene deposits of the Siwalik Hills in North-Eastern India. The well-known genus Arius, from all the tropical regions of the world, belongs to another group of the same subfamily, in which the front and hinder nostrils are close together, but have no barbel, although the hinder-pair are provided with a valve. The Tropical American genus Pimelodus is the typical representa- tive of a third group of the same subfamily, in which the two pairs of nostrils are equally devoid of barbels, but are placed at a considerable distance apart. The CAT-FISHES. 455 largest species is the leopard cat-fish, or suravi (P. pati), from the rivers of Argentina and Uruguay, growing to a length of 6 or 7 feet, and having the yellowish skin marked with a number of black spots, like a hunting-leopard. Somewhat curiously, this genus is represented by two outlying species from West Africa. The best known representative of the fourth and last group of genera in this subfamily is the bayad (Bagrus bayad) of the Nile; the group being easily recognised by the circumstance that while the two pairs of nostrils are remote from one another, the hinder have barbels. Both species are confined to the Nile, but the allied Chrysicthys ranges all over Tropical Africa, and Macrones and Rita are Oriental forms. In these forms the short dorsal fin has a pungent spine, and the head and neck are generally protected by a tuberculated bony shield. Electric Cat- On account of the property from which they derive their name Fishes. brief mention must be made of the electric cat-fishes (Malapterurus) of Tropical Africa, belonging to a subfamily in which the rayed dorsal fin, when present, is short and confined to the hinder region of the body, while the pelvic fins are inserted behind. From their allies these fishes are distinguished by the total absence of the rayed dorsal, so that they have only a fatty dorsal immediately in front of the tail (which is rounded), and opposite the anal. The head and body are smooth, the pectoral fins have no spine, and there are six barbels. The species inhabiting the Nile grows to about 4 feet in length. Mailed Cat- The only other members of the family, which space admits of Fishes. mentioning, are the mailed cat-fishes (Callichthys, Loricaria, etc.), constituting a subfamily mainly confined to Tropical and South America, although represented by a few Oriental forms. In all these fishes there is always a rather short rayed dorsal fin, beneath or in front of which the pelvics are generally inserted. The gillanembranes are confluent with the skin of the isthmus, and the gill-openings constricted to small slits. The pectoral and pelvic fins are placed horizontally ; and the vent is in front of, or only slightly behind, the middle of the length of the body. Among these fishes the species of the genus Callichthys, which are confined to the rivers on the Atlantic side of South America, belong to a group characterised by the nearness of the two pairs of nostrils, between which there is generally a short flap, and by the expansion and reversion of the lower lip to form a broad flap more or less deeply notched in the middle. In the genus mentioned, the head is covered with bony plates, and the body encased in two rows of transversely elongated overlapping shields on each side; all the species being of small size. Like certain other South American forms belonging to another sub- family, of which the members of the genus Doras are perhaps the best known, these mailed cat-fishes are in the habit of making nocturnal journeys during the hot season, when the pond they inhabit is about to dry up to another of greater capacity, and they likewise construct nests for their eggs. In the case of the genus last mentioned, these Journeys may occupy several nights, during which the fish travel in large companies. As they have no special breathing-sacs, they must apparently close their gill-openings, and thus keep the gills moist. The nests, which are made at the beginning of the rainy season, are formed of leaves, beneath which the eggs are deposited and watched over by both parents; the whole structure being sometimes placed in a hole on the margin of the river or pond. 456 LOBLEL-BILADDERED (GIco Ofz In the armoured eat-fish, forming the genus Loricaria, the body is remarkable for its elongated and slender form; while the head is depressed, with a more or less produced and spatulate snout, on the under surface of which the mouth is situated at a considerable distance from the extremity, its margins being surrounded by large folds, and each corner having a barbel. Both the dorsal and anal fins are short and elevated, and the entire head and body enveloped in a bony cuirass. s SECTION PLECTISPONDYLI. THE Carp TRIBE,—Family CYPRINID. Adopting a modification of Professor Cope’s classification, the eels and their allies may be regarded as forming one sectional group of the suborder, while the cat-fishes constitute a second by themselves. A third equivalent group will then be made by the carps, together with the under-mentioned family of the characinoids and certain allied forms. This third group—for which the name Plectispondyli has been proposed—while agreeing with the cat-fishes (forming the group Nematognathi) in having the first four vertebrae fused together and highly modified, differs in the presence of a subopercular bone. As in the last family, the margin of the upper jaw is formed by the premaxille, and the whole mouth is toothless, teeth being developed on the pharyngeal bones alone. While the head is invariably naked, the body is generally covered with scales, and although it may be scaleless it is never invested with bony plates. False gills may be developed, and, if so, are glandular. When an air-bladder is present, it is always of large size; and it may be divided into two lateral moieties enclosed in an ossified capsule, or constricted into an anterior and posterior portion which are not thus protected. The numerous members of this family are fresh-water fish, confined to the Old World and North America, being quite unknown in the southern half of the New World, and also in Australia. Showing much less diversity of form and habits than the cat-fishes, the carp tribe are for the most part omnivorous, although a few of its members restrict themselves to a vegetable diet. Although some of them prefer muddy situations, where their barbels are probably of assistance, the majority of the carps differ from the eat-fish in selecting clear waters for their haunts. The Indian forms seem to be more carnivorous than their European relatives, many of the larger kinds preying upon their smaller brethren. Geologically, the carps appear to be a comparatively modern group, the earliest known forms occurring in the Eocene of Sumatra; these being identified with existing Oriental genera. Other fossil carps have been obtained from the North American Eocene, and are assigned to extinct generic types; while in the Continental Miocene we find representatives of a number of the existing European genera, as well as of a few now mainly or exclusively Asiatic. On account of their more cleanly feeding-habits the flesh of the carps is superior to that of the cat-fishes. The family is represented by over a hundred existing genera, arranged under two subfamilies. rinses The common carp (Cyprinus carpio) claims our attention as the typical representative of the subfamily Cyprinine, characterised by the air-bladder (wanting in one Oriental genus) not being enclosed in bone, and divided into an anterior and posterior moiety. In the Oriental genus (Homalop- CARTE TRIBE: 457 terus) without an air-bladder the number of barbels is six, but otherwise there are never more than four of these appendages, which may be reduced to a single pair, or be wanting. alone to a group in which the anal fin is short and usually furnished with five or six pemiched rays, the true carps have the lateral line running along the middle of the tail, the dorsal fin placed opposite the pelvies, and containing a more GROUP OF CARP. 1, Carp; 2, Large-scaled variety of Carp ; 3, Crucian Carp: 4, Barbel (4 nat. size). or less strongly serrated bony ray, and more than nine branched rays, while the pharyngeal teeth are arranged in three series, with those of the outermost one molar-like. The muzzle is rounded and blunt, with four barbels, and the rather narrow mouth at its extremity. The true carps form a small genus confined to the temperate parts of Europe and Asia, the common species being a native of the latter continent, and abundant in a wild state in China, where it has also long been domesticated. Thence it was introduced into Germany and Sweden, and subse- 458 TUBE-BLADDERED GROUP. quently into Britain—it is said early in the seventeenth century. The ordinary form is shown in the upper figure of the illustration on p. 457; but there are many domesticated varieties, differing either in the form of the body or the size and arrangement of the scales. Among the latter, one of the most remarkable is the so-called spiegel-karpfen (mirror-carp), Shown in the right-hand middle figure of the illustration. In this variety, which is found only in ponds, the scales are three or four times the normal size, and instead of covering the whole body are arranged in from one to three longitudinal rows, with bare skin between them. In Western Europe the carp has taken kindly to its new habitat, not unfrequently attaining as. much as a yard in length, with a weight of 25 lbs., while very much larger specimens. are on record. Preferring still waters, with a soft muddy bottom in which it erovels with its snout for food, the carp feeds on various vegetable substances, as. well as on insects and other small aquatic invertebrates. When the surface of their haunts is locked in ice, carp le deeply buried in holes in the mud, frequently consorting in numbers, and undergoing a partial hibernation, which is not broken till the returning warmth of spring. Their growth is extremely rapid, and their fecundity extraordinary, nearly three-quarters of a million eggs having been counted in the roe of a medium-sized specimen. They are capable of living a considerable. time out of water, especially if they are moistened from time to time; and are known to live to a very great age. Carp will interbreed both with the Crucian and golden carp. Crucian and Easily distinguished by the absence of barbels, the Crucian carp: Golden Carp. (Curassius vulgaris), and the golden carp, or gold-fish (C. awratus). are the best known representatives of another closely allied genus; the former being a native of Central and Northern Europe, but also found in Italy and Siberia, while the home of the second is China and the warmer parts of Japan. Both are comparatively small species, and have been long domesticated; whereas, however, the Crucian carp always retain the original brownish colour, the domesticated variety of the golden carp has assumed the well-known golden tinge from which it takes its name; an albino form being also known. Among the numerous varieties. of this fish the most curious is the so-called telescope-fish, shown in the right-hand figure of the illustration on p. 412, taking its name from the prominence of the highly movable eyes, and likewise characterised by the great development of the caudal fin. In Europe gold-fish thrive best in waters heated somewhat above the ordinary temperature, and they are accordingly frequently kept in engine-ponds, where the water may have a temperature of some 80°, and in which they breed freely. The Crucian carp, Shown on the left of the illustration on p. 457, is con- fined to ponds and lakes, where it seeks the deepest parts. Represented by some two hundred species from the tropical and temperate regions of the Old World, the barbels are best known by the common European species (Barbus vulgaris), shown in the lower figure of the illustration on p. 457, and the gigantic mahasir (B. tor) of India and Ceylon. Agreeing with the carps in the structure of the anal fin, and the position of the lateral line and dorsal fin, they belong to a subgroup of genera in which there are generally not more than nine rays in the dorsal fin, the pharyngeal teeth being arranged in three rows, the greater part of the cheek not covered with bone, the Barbels. CARP TRIBE. 459 anal scales not enlarged, and the eye unprovided with a fatty ld; while they are specially characterised by the arched mouth—which is devoid of internal folds—and by the presence of false gills. The anal fin is frequently tall, the lips are devoid of any horny covering, and the barbels, if present, may be either two or four in number. The scales may be either small or very large, and the body is frequently of a much more elongated form than in the true carps. While some species are not more than 2 inches in length, the mahasir, and some other kinds, may grow to at least 6 feet. Of the Indian forms, Day writes that those with four barbels (among which is the mahasir), “ provided they are soberly coloured, attain a large size; the brilliantly coloured forms are mostly residents in clear or rapid mountain- streams, or rivers contiguous to hills, and generally small. A strong dorsal spine is usually (if not invariably) a sign that the species lives in the vicinity of high mountains, the streams of which it ascends to breed. An exception has, however, to be made of those forms with serrated dorsal spines, which are usually resident in the waters of the plains.” The common barbel, which has four of the appendages from which it derives its name, not uncommonly grows to a length of 2 feet, with a weight of from 8 to 10 Ibs., but may attain much larger dimensions. Oa Confining our attention mainly to the European representatives of the family, we have next to mention the gudgeons ((robi0), which may be distinguished from the foregoing by the pharyngeal teeth being arranged in a double or single series; the body being entirely covered with scales; and the muzzle having two small barbels, with the mouth inferior in position, and the premaxillary bones protractile. The scales are of moderate size, the short dorsal fin has no spine, and the intestine is remarkable for its shortness. These small fishes are represented only by two species, of which G. fluviatilis is British; and, like the barbels, they are purely animal-feeding. The British species 1s shown in the lower figure of the illustration on p. 462. From the whole of the members of the family noticed above the so-called “ white-fish ” belong to a group of genera in which the anal fin is short or of medium length, with from eight to eleven branched rays, and not extending forwards beneath the line of the dorsal; the lateral line, when complete, running nearly or quite in the middle of the tail. From certain allied forms they are distinguished by the short dorsal fin having no bony ray; and the pharyngeal White-Fish. teeth form a single or double series, the margin of the lower jaw is not cutting, and there are no barbels. As distinctive peculiarities of the white-fish may be mentioned the protractile premaxillary bones, the imbricating scales, and the smooth outer surface of the pharyngeal teeth. The numerous representatives of the white-fish are distributed over the rivers of the North temperate zone, the New World forms somewhat exceeding in numbers those of the Old. Among the European representatives of the genus, the roach (Leuciscus rutilus), shown in the right- hand middle figure of our illustration, agrees with several other species in having a single series of pharyngeal teeth, at least ten rays in the anal fin, and the dorsal nearly opposite the pelvic fins; its deep body being silvery, and the lower fins of the adult generally tinged with red. Its range is confined to Europe north of the Alps. On the other hand, the chub (Z. cephalus), shown in the lower figure of the illustration, may be selected as an example of a second group in which there are two 460 TUBE-BLADDERED GROUP. series of pharyngeal teeth. This fish has a somewhat wider distribution than the last, extending southwards into Italy and eastwards into Asia; it is uniformly coloured, with greyish margins to the scales. To the same group of the genus belongs the dace (L. vulgaris), with the same distribution as the roach, to which it presents a considerable external resemblance, although smaller and longer in form ; GROUP OF WHITE-FISH. Ide, Rudd, Roach, and Chub (4 nat size). its sides being silvery, but the fins not tinged with red. Roach and dace are commonly found in company, and have identical habits. The fish shown in the upper figure of our illustration is confined to the central and northern countries of the Continent, where it is known as the ide (Z. idus), and is a uniformly-coloured species nearly allied to the last. It is of special interest on account of a golden- coloured domesticated variety bred in Germany, and known as the orfe. Another CARP TRIBE. 461 member of the same group is the rudd or red-eye (L. erythopthalmus), of which a specimen is represented in the left-hand middle figure of the illustration; this species, which ranges all over Europe and Asia, may be distinguished by its scarlet lower fins, the general hue of the scales being coppery. The familiar and diminu- tive minnow (L. phoxinus) differs from all the foregoing members of this group by the incomplete lateral line ; its range being limited to Europe, although it is repre- sented by an allied species in North America. The habits of all these familiar fish are too well known to need notice; but it may be mentioned that several of them will interbreed, as they will with species belonging to other genera of the family. Representing a genus by itself, the European tench (Tica vulgaris) differs from the white-fish by the presence of a small pair of barbels to the mouth; the pharyngeal teeth forming a single series. The small Tench. TENCH (4 nat. size). scales are deeply embedded in the thick skin; there is a complete lateral line; both the dorsal and anal fins are short; and the caudal, instead of having the markedly forked form characteristic of the roach and its allies, is but slightly emarginate. The terminally-situated mouth has its lips moderately developed. Whereas white- fish prefer clear running streams, the tench frequents ponds, lakes, and other more or less stagnant water; its colour, which is sometimes bronzy golden, and in other cases Olive-green, with a more or Jess blackish tinge, is stated to vary with the purity or otherwise of the water in which it lives. Tench always keep near or in the mud, beneath which they entirely bury themselves during the colder months, after the fashion of so many members of the family. A good tench will weigh 4 lbs., but examples of 5 lbs., and even over, are not very uncommon. It is probably owing to the abundant supply of mucus secreted by the skin that the tench was considered to be endowed with healing powers. Tench are exceedingly prolitic, and as they bear transport easily, are admirably adapted for stocking ponds. 462 TUBE-BLADPDERED (GROOFP. = By this name may be distinguished.a small genus, containing Beaked Carp. : ; zi c > 7 ; seven species, from Continental Europe and Western Asia, and differing from the two foregoing by the margin of the lower jaw forming a cutting edge, overlain with a brown horny layer; one of the species (Chondrostoma nasus) being represented in the lower figure of the illustration on p. 465. These fishes are further characterised by the medium or small size of the scales, the termination of the lateral line in the middle of the deepest part of the tail, by the dorsal fin having not more than nine branched rays, and being situated opposite the root BITTERLING, BLEAK, AND GUDGEON (nat. size). of the pelvics, and also by the rather elongate anal bearing ten or more rays. The mouth is inferior in position, and transverse; and there are no_barbels. Commonly known in France as le vez, the figured species does not usually exceed 18 inches in length, with a weight of about 3 lbs. It is generally found in deep water, where it feeds on various vegetable substances, but more especially on the green confervoid growth covering submerged stones, which is neatly mown off by a seythe-like action of the horny margin of the transverse lower lip. Seesrtie The small voach-like fish known as the bitterling (Rhodeus amarus), of which two examples are shown on the left side of the accompanying illustration, is the European representative of four genera of small CARP TRIBE. 463 o carps mainly characteristic of Eastern Asia and Japan, and having the following distinctive features. The anal fin is of moderate length, and extends forwards to below the line of the dorsal; the lateral line, when fully developed, runs on or ‘near the middle of the tail; and there is but a single series of pharyngeal teeth. The bitterling, which belongs to a genus characterised by the incomplete lateral line, and the small size of the scales, is locally distributed in Central Europe, where it is not unfrequently found in hot springs. It is one of the smallest of European fishes, the females being generally about 14 inches in length, while the males do not exceed twice this size. The name is derived from the bitter taste of the flesh; and it is only perch and eels that will take this fish when used as a bait. In common with its allies, the bitterling is remarkable for the circumstance that in the breeding-season the oviduct of the female is produced into an elongated tube, projecting a considerable distance beyond the surface of the body. This organ, which may be compared to the ovipositor of an insect, is introduced within the shells of fresh-water mussels, and the eggs are thus deposited in a situation where they will be protected from the attacks of enemies. The common European bream (Abrams brama), shown in the lower figure of the illustration on the next page, is the type of a large group of genera, characterised by the elongation of the anal fin, and by a portion or the whole of the abdomen being compressed so as to form a sharp edge. In the type genus the much compressed body is deep or oblong in form, with the scales of Bream. moderate size, and the lateral line running below the middle of the tail; the short dorsal fin, which is not furnished with a spine, being situated opposite the interval between the pelvic and anal fins. In both jaws the lps are simple, the upper being protractile, and generally longer than the lower, although occasionally the reverse condition obtains. The pharyngeal teeth may be arranged in either a single or double series; and the scales do not extend across the sharp edge of the lower surface of the hinder part of the body. Distributed over Europe north of the Alps, portions of Western Asia, and North America, the breams are repre- sented by about fifteen species, of which the common bream and the white bream (A. blicea) are found in Britain. The white bream, shown in the upper figure of our illustration, has the general colour of the sides bluish white, without any trace of the golden yellow lustre, from the presence of which the common species is often termed the carp-bream. They may also be distinguished by the iris of the eye in the latter being yellow, and in the former silvery white, tinged with pink. Yarrell writes that “bream swim in shoals, feeding on worms, and other soft-bodied animals, with some vegetable substances; and if the water they inhabit suits them, which is generally the case, as they are hardy in their nature, they grow rapidly, and spawn in May. At this season one female is generally followed by three or four males, and they bear at this time a whitish tubercle on their scales, which causes them to feel rough to the hand.” In some of the Irish lakes bream run to as much as 12 or 14 lbs. in weight; and as they are a greedy fish, great numbers can be taken by the aid of ground-baiting. Of the other two species here figured, the zope (A. ballerus), forming the second figure from the top, is an inhabitant of Germany, Holland, and Sweden; while the zarthe (A. vimba), is found in the Danube, as well as in the rivers of North Germany, Sweden, and Russia. The 64 TOUBE-BLADDERED GROUF. rae latter species may be easily recognised by the keeled upper surface of the tail, and the projecting muzzle; while the zope is characterised by the great elongation of the anal fin, which commences opposite to the dorsal, and extends nearly to the tail, combined with the oblique direction of the cleft of the mouth. Te Me Up of Meee hdl GROUP OF BREAM. White Bream, Zope, Zarthe, and Common Bream (4 nat. size). By this name is known in Austria the typical representative (Aspius rapax) of a small genus of carps, containing four species from Eastern Europe and China, and somewhat intermediate in structural characters between the breams and the bleaks. Agreeing with the former in the shortness of the gill-rakers, these fishes always have the lower jaw projecting considerably beyond the upper, which is but slightly protractile; the anal fin never has less than thirteen rays; and the sharp lower edge of the abdomen Rapfen, behind the pelvic fins is crossed by the scales. Common in Eastern and Northern CARP TRIBE. 465 Europe, although unknown in the British Islands, the rapfen, is generally found in lakes or rivers flowing through level country, as it requires clear but tranquil waters, In colour it is bluish black above, with the sides bluish white, and the under surface white; the dorsal and anal fins being blue, and the others tinged with red. In weight this fish does not exceed a dozen pounds, and in length never measures more than a yard. SICHEL, RAPFEN, AND BEAKED CARP. Especial interest attaches to the beautiful little fish known as the bleak (Alburnus lucidus), of which a figure is given on the right side of the illustration on p. 462, on account of the use of the pearly matter from its scales in the manufacture of artificial pearls. Of bleak there are fifteen species, ranging over Europe and Western Asia; the common British species being found only to the north of the Alps, although represented by an allied form in Italy. From both the preceding genera these fish are distinguished by the slender and lanceolate form of the closely set gill-rakers. The body is more or less VOL. V.—30 Bleak. 406 LOUBH-BLADDERE DT GIRO OP. elongate, with the scales of moderate size, and the lateral line running below the middle of the tail. The fins are generally similar to those of the last genus; and the lower jaw projects more or less beyond the upper, which is protractile. In the hinder part of the abdomen the scales do not extend across the sharp lower edge. Generally about 4 or 5 inches in length, and never exceeding 7, the common bleak is steel-blue in colour above, with silvery white sides and under surface, and the dorsal and caudal fins grey, the others being colourless. It is found in rivers, lakes, and ponds, preferring clear water; and in calm, warm weather swimming rapidly about near the surface in search of flies and other insects. During the spawning-season, which is in May and June, bleak collect in large shoals, which are preyed upon not only by perch, but likewise by gulls and terns. Nearly allied to the bleak is a small fish (Lewcaspius delineatus) from the rivers of Eastern and Southern Europe, distinguished by the extreme shortness of the lateral line, which scarcely extends beyond the extremities of the pectoral fins. The scales also are of a regular ovate form, without the distinct fan-like rays so characteristic of the bleak. The last member of this great subfamily that we shall mention is the curious-looking fish (Pelecus cultratus) shown in the upper figure of the illustration on p. 465, known in Germany as the sichel, and forming the sole representative of its genus. It is at once characterised by the whole of the abdominal surface of the oblong and compressed body forming a sharp cutting edge; the scales being small, and the lateral ine making a sudden descent behind the pectoral fin towards the lower surface. The cleft of the mouth is always peculiar in having a nearly perpendicular direction. The pectoral fins are unusually tall, and the dorsal is placed far back, and above the anal, which resembles that of the bream in its numerous rays. On the pharyngeal bones the teeth are arranged in a double series, and are strongly hooked. In profile this fish, which generally ranges from 6 inches to a foot in length, is remarkable for the straightness of the line of the back, and the convexity of its lower border. It is widely distributed in Eastern Europe, being common in the Black and Caspian seas, as well asin their affluent rivers. In form this fish makes a curious approach to the members of the herring tribe. With the small fishes known as loaches, of which there are three European genera, we come to the second subfamily (Cobitine) of the carp tribe, which is characterised by the air-bladder being either partially or entirely enclosed in a bony capsule; false gills being always absent. In these fishes the body may be elongate, oblong, compressed, or cylindrical, but is never depressed ; the muzzle and lips are fleshy; and the small, inferiorly-placed mouth Sichel. Loaches. is furnished with from six to twelve barbels. The median fins are spineless, the dorsal having a variable number of rays, but the short anal possessing but few, while the pelvic pair may be wanting ; scales small, rudimental, or absent, and when present, cycloid, and usually immersed in mucus; in one Oriental genus, developed upon the back and sides of the head. The loaches of this subfamily are confined to Europe and Asia; and while some of those from the former continent are partial to swift clear streams with a stony bottom, the Indian forms delight in CARP TRIBE. 467 muddy tanks, where they bury themselves in the mud. All are carnivorous; and, in spite of their small size, the European species are esteemed as food. The giant loach (Misgurnus fossilis), forming the central figure of our illustration, is the largest European member of the group, and belongs to a genus of four species, common to Europe and Asia north of the Himalaya. The genus is characterised by the elongate and compressed form of the body, the absence of an erectile spine near the eye, and the presence of from ten to twelve barbels, four of which belong to the lower jaw; the dorsal fin being placed above the pelvic pair, and the caudal vounded. The European species, which grows to a length of 10 inches, is found in stagnant waters in Southern and Eastern Germany, and North-Western Asia ; GIANT LOACH, COMMON LOACH, AND SPINY LOACH (4 nat. size). being replaced by an allied form in China and Japan. The true loaches (Vema- chilus), on the other hand, have six upper barbels, and none on the lower jaw. They are represented by some fifty species from Europe and Temperate Asia; the common British loach (WV. barbatulus), shown in the upper figure of the illustration, being found in clear streams all over Europe with the exception of Denmark and Scandinavia. The spiny loach (Cobitis tenia), shown in the lower corner of the illustration, is the typical representative of a third genus, distinguished from the last by the presence of a small, bifid, erectile spine below each eye. The figured species is locally and sparingly distributed in Britain, but more common on the Continent. Certain Indian loaches formerly included in this genus are now regarded as distinct, the subfamily being represented by eight other gener: in the same country. 468 TOUBE-BEADDERED (GROUE. AFRICAN LOACHES,—Family A NERD. Two small loach-like fishes from the fresh waters of Tropical Africa, one of which (Kneria congolensis) is figured in the annexed illustration, alone represent a family distinguished from the preceding by the absence of teeth on the pharyngeal bones, and by the elongated air-bladder being undivided, barbels beg wanting. While the figured species is from the west coast, the other (AY. spekei) inhabits Central Africa. THE CHARACINOID FISHES,—Family LRYTHRINIDA. As an example of a very extensive family of fresh-water fishes, confined to Tropical America and Africa south of the Sahara, we select an American form known as the piraya (Serrasalmo piraya), since in our limited space it is quite impossible to deal with any of the others. , It may be mentioned, in the first place, ANGOLA LOACH (nat. size). that these fishes are commonly known as the Characinide, but as there is no such genus as Characinus, it is obvious that this term cannot stand, and we have accordingly adopted another. According to Professor Cope’s arrangement, these fishes belong to the same sectional group as the carp tribe, from which they may be distinguished by the brain-case not being produced between the orbits, and likewise by the number of upper pharyngeal bones varying from four to one instead of being always two; a further point of difference occurring in the structure of the upper jaw, which is formed in front by the premaxille, and at the sides by the maxille. Like the carps, the hody is sealed and the head naked ; but barbels are invariably wanting, and the jaws may be either toothless, or furnished with a dentition of a very powerful type. In most cases there is a small fatty fin behind the dorsal; the air-bladder is always transversely divided into halves, and there are no false gills. Unfortunately, there are no fossil forms to aid in the explanation of the peculiar geographical distribution of the family, which is very similar to that of the chromids:; but there can be little doubt that the ancestral types originally inhabited the great land-mass of the Northern Hemisphere, from whence they migrated southwards to their present isolated CHARACINOIDS. 469 distributional areas. It is, however, not a little remarkable that whereas in their migration to Africa they have been accompanied by members of the carp tribe, in Tropical America they entirely take the place of that family. The numerous genera, none of which are common to the two hemispheres, are ranged under eleven groups or subfamilies, the majority of which are confined to either the one or the other half of the distributional area, although a few have representatives of both. As regards their habits, some of these fishes are strictly carnivorous, while others are as exclusively vegetable-feeders. The figured species belongs to the last subfamily, which includes four exclus- ively American genera, represented by some forty species, and characterised by the somewhat elongated dorsal fin, behind which is a small fatty fin; by the gill- membranes being free from the isthmus, and also by the distinct serration of the middle line of the under surface of the body. On account of their large size, two other genera of these fishes, which have respectively received the names of Hydrocyon and Cynodon, must be mentioned ; THE PIRAYA (4 nat. size). the former being from Tropical Africa, and the latter from Brazil and the Guianas. They grow to the length of 4 feet, and are highly predacious; the subfamily to which they belong being characterised by the presence of a short dorsal and anal fin, the large conical teeth, the want of attachment between the gill-membranes and the isthmus, and the approximation of the nostrils. THE CYPRINODONTS,—Family CYPRINODONTID. The small fishes which, for want of an English title, we may designate cyprinodonts, bring us to the first family of another sectional group termed the Haplomi, which also includes the pikes. In addition to certain other structural features of the skeleton, this group is characterised by the first four vertebrae being 470 TUBE-BLADDERED GROUP. separate and of normal form; while in the skull the parietal bones are separated by the supraoccipital, all the opercular bones are present, and the pharyngeals are distinct, the upper ones being directed forwards, and three or four in number. As a family, the cyprinodonts are specially distinguished by the margin of the upper jaw being constituted solely by the premaxille, and the enlargement of the third upper pharyngeal bone. Externally they may be readily distinguished from the carps by the head being scaled as well as the body, and they have no barbels. Both jaws are toothed, and the pharyngeals are also furnished with teeth, which are heart-shaped. There is no fatty fin, and the dorsal is situated in the hinder half of the body. The air-bladder is simple, and the false gills are wanting. Inhabiting either fresh, brackish, or salt water, these fish are distributed over the south of Europe, Africa, Asia, and America; some being purely carnivorous, while others feed ‘on the organic substances to be found in mud. Most of the forms are viviparous; and the males, which are much inferior in size to the females, and, according to Dr. Giinther, probably the smallest living fishes, frequently have the anal fin specially modified to aid in the reproductive process. Asa rule, the fins are relatively larger in the males than in the females, and there is likewise some difference in the coloration of the two sexes. In a fossil state, remains of the typical genus occur in the Miocene strata of the Continent, which have also yielded others re- ferred to an existing American genus; while the head of a species much larger than any now living has been described from the Pliocene of India, this specimen being figured in the accom- panying illustration in order to show the scales on the head so characteristic of the family. Cyprinodonts are represented by about a score of genera, which may be divided into two sub- families, according to the nature of the food. In the first of these, which includes the typical genus Cyprinodon, and has a distribution co- extensive with that of the family, all the forms HEAD OF A FOSSIL CYPRINODONT, WITH g : : : ONE OF THE SCALES ENLARGED. are carnivorous or insectivorous, and are char- acterised by the firm union of the two branches of the lower jaw in front, and likewise by the shortness, or slight convolution of the intestines. On the other hand, in the second subfamily, which is exclusively restricted to ‘Tropical America, the species seek their food in mud, and have the two branches of the lower jaw but loosely joined together, while the intestine is highly convoluted. Itis in this group that the sexual differences are most strongly marked. Deere As an example of the family we take a remarkable genus belonging to the first subfamily, represented by three species from Tropical America, one of which (Anableps tetropthalmus) is shown in the accom- panying illustration. Having a broad and depressed head, with the region over the eyes much raised, the elongate body compressed in front and depressed behind, a protractile muzzle, and the cleft of the mouth horizontal and of moderate size, these BLIND FISH. A471 fish are specially characterised by the structure of the eye, which is quite unique among vertebrates, and from which they derive their name. In each eye the integuments are divided into an upper and a lower moiety by a dark-coloured transverse band in the outer layer; the pupil being likewise bisected in the same plane by means of a lobe projecting from each side of the iris. The scales are of small or moderate size; the dorsal and anal fins short, the latter being placed in advance of the line of the former, and in the male (which in this genus is larger than the female) modified into a long, thick, scaly organ, with an aperture at the end. ‘These fishes are the largest existing members of the whole family, growing nearly to a foot in length. They are abundant in North Brazil and the Guianas, where they frequent mud-banks on the coast and in the estuaries of the larger FEMALE AND MALE DOUBLE-EYE (3 nat. size). rivers; many of them being often left stranded by the retiring tide, where they progress on the slime by a series of leaps. After birth the young are carried about by the female in a thin-skinned sae divided by a partition, until they are suffici- ently advanced to take care of themselves. When swimming, these fishes frequently go on the surface with the eye half in and half out of the water; and it is in accordance with this habit that the eyes are divided, the upper portion being able to see in the air, while the lower is adapted for vision under water. That such is really the case, is proved by the structure of the lens of the eye. In terrestrial animals the lens is lenticular, that is to say, of the shape of two watch-glasses put edge to edge; whereas in ordinary fishes, which have to see in such a dense medium as water, the lens is spherical. Now in the double-eye that portion of the organ of vision which is above the level of the water has the lens lenticular, while in that portion which is below the water the lens is spherical. In Brazil the flesh of these fish forms an article of consumption. 472 TUBE-BLADDERED GROUP. THE BiLInD-FisH,—Family AMBLYOPSID. The celebrated blind-fish (Amblyopsis speleea) from the Mammoth Cave in Kentucky, the Wyandotte Cave in Indiana, and the subterranean streams which appear to connect the waters of the two, is generally regarded as the typical repre- sentative of a family closely allied to the last. This fish, which does not exceed 5 inches in length, and breeds viviparously, closely resembles the genus Cyprinodon in that certain specimens (which have unnecessarily been separated as Typhlichthys) lack the pelvic pair of fins. All traces of external eyes are wanting, and the skin is totally devoid of colour. In order to enable the creature to find its way about in the dark subterranean waters of the limestone rocks of the Central United States, its head is provided with a large supply of organs of touch, arranged in a series of transverse ridges on each side; while its sense of hearing is also stated to be very highly developed. Professor Cope writes that if these fish “be not alarmed, they come to the surface to feed, and swim in full sight like white aquatic ghosts. They are then easily taken by the hand or net, if perfect silence is preserved, for KENTUCKY BLIND-FISH (nat. size). they are unconscious of the presence of an enemy except through the medium of hearing. This sense is, however, evidently very acute, for at any noise they turn suddenly downwards and hide beneath stones, ete., on the bottom. They must take much of their food near the surface, as the life of the depths is apparently very sparse. This habit is rendered easy by the structure of the fish, for the mouth is directed partly upwards, and the head is very flat above, thus allowing the mouth to be at the surface. It thus takes food with less difficulty than other surface-feeders, as the perch, where the mouth is terminal or even inferior; for these require a definite effort to elevate the mouth to the object floating on the surface.” Nearly allied to that variety of the blind-fish in which pelvic fins are absent is a small fish known as Chologaster, in which small external eyes are retained, and the body is coloured ; the front of the head being provided with a pair of horn- like appendages. These small fish were first known from three examples taken in the ditches of the South Carolina rice-fields, but a fourth specimen was captured in a well in Tennessee in the year 1854. The retention of the eyes and their dark colour indicates that these fishes have taken to a partially subterranean life more recently than the blind-fish. PULTE. 4 ~I ww THE Umpres,—Family UveripZ. A small fish from Austria-Hungary known as the umbre (Umbra kramer‘), together with a second (U. limi), locally distributed in the fresh waters of the United States, indicate a family distinguished from the Cyprinodontide by the upper jaw-margin being formed in front by the premaxillary bones and by the maxillary bones at the sides; the base of the skull being of simple structure in both families. Like the cyprinodonts, the umbres have the head and body scaled, and no barbels to the mouth. There is no fatty fin, and the dorsal is opposite the pelvics, or a little behind them, while the anal is short, and the caudal rounded. The stomach merely forms an expansion of the intestine ; the air-bladder is simple; and the false gills are hidden and glandular. The European species, which is known as the hunds-fisch in Germany, dwells in marshes and muddy pools, where it buries itself in the mud at the bottom. As in most cyprinodonts, the males are smaller and more slender than the females, scarcely reaching a couple of inches in length, whereas the latter grow to 3 or 33 inches. THE PIKE,—Family HsocrDZ. Such a familiar fish as the pike (sox Lucius) scarcely requires much in the way of description, but it is an important one as representing, with other members of the same genus, a family by itself. Agreeing with the umbres in the structure COMMON PIKE. of the jaws, pike may be distinguished externally by the absence of scales on the head, and internally by the more complex structure of the base of the skull. The body is covered with cycloid scales; there are neither barbels nor a fatty fin; and the dorsal is situated in the caudal region of the vertebral column, in the position of the fatty fin of the salmon tribe. The stomach has no blind appendage, the false gills are glandular and concealed, and the gill-opening is unusually wide. In the upper jaw sickle-shaped teeth are borne by the premaxille, palatines, and vomer, the maxille being toothless, while the lower teeth are of variable shape. The long narrow body terminates in a forked caudal fin; and the long, broad, and depressed snout has the lower jaw exceeding the upper in length. Confined to the fresh waters of the temperate regions of the three northern continents, pike may be considered a western rather than an eastern type, seeing that whereas the common species has a range equivalent to that of the family, the whole of the other six species are confined to the United States. In Europe the pike inhabits 474 LOBE BDLADDERED (GROG: all the Russian rivers, with the exception of those of. the Crimea and Trans- caucasia, and is likewise found in Siberia. In Lapland it extends even beyond the limits of the birch, while to the south it is common in the Venetian lagoons. Growing very rapidly, the pike not uncommonly attains a length of 45 or 46 inches, with a weight of 35 or 36 Ibs.; and although fishes of much larger dimensions are on record, the accounts of these must be received with great caution. It is pretty well ascertained that fish of 45 inches are not commonly more than about fifteen years old, and the stories of examples living for a century, or even more, appear to be legendary. Pike are among the most predaceous and greedy of all fresh-water fish, nothing coming amiss to their voracious appetites, since not only will they devour worms, leeches, frogs, trout, carp, and other fishes, but they pull under the young, and often even the adults, of all kinds of water- birds, and have no objection to an occasional water-vole. Their habit of lying like a log in the water (from which trait they probably derive their name), as well as the sudden rush they make after their prey, are well known to all; and the damage these fish do to trout-streams is almost incredible. Pike are also great devourers of the smaller members of their own kind. Frequenting alike ponds, lakes, and rivers, pike in Ireland spawn as early as February, but in England a month or two later, while in some parts of the Continent the season lasts till May. Males, which are inferior in size to their consorts, are said to be more numerous than the latter; and it is not uncommon for a female in spawning-time to be attended by three or four members of the opposite sex, who crowd around her as she lies quiet to deposit her eggs. THE AFRICAN BEAKED FisH—Family MoruyvripZ.. The very remarkable fish (Mormyrus peters:) shown in the upper figure of the illustration on p. 475, is the best known African representative of a large genus of fresh-water fishes confined to Africa, and constituting not only a family but likewise a distinct section, to which Professor Cope applies the name of Seyphophori. Having the narrow parietal bones of the skull distinct both from one another and from the supraoccipital, these fishes are especially distinguished by having each of the pterotics (which lie on each side of the parietals) large, funnel-shaped, and enclosing a cavity expanding externally, and covered by a hid-lke plate of bone. The anterior vertebre are simple and unmodified; and a subopercular bone is present in the gill-cover. Externally both the body and tail are covered with scales, but the head is naked, and the muzzle has no barbels. In the upper jaw the middle portion is formed by the united premaxille, and the sides by the maxille; the gill-opening is reduced to a small slit; there are no false gills; and the air-bladder is simple. A fatty fin is wanting; and whereas in the typical genus all the other fins are well developed, in the allied (rymnarchus (which is likewise exclusively African, and is sometimes regarded as the representative of a distinct family), the caudal, anal, and pelvic fins are want- ing, the tail tapering to a point, instead of terminating in a deeply forked fin. The beaked fishes are divided into groups according to the length of the dorsal fin and the form of the muzzle, the figured species belonging to a group in which FEA TPHEROBA CES. 475 the dorsal fin is relatively short, scarcely exceeding the anal in length, while the muzzle is long and bent down. From its nearest allies the species in question is distinguished by the production of the extremity of the lower jaw into an elongated, conical, dependent, fleshy appendage, nearly equal in length to half the head. In colour the skin is dark brown, relieved by two lighter crossbands between the dorsal and anal fins. Other species have the muzzle short and blunt ; and whereas some grow to a length of between 3 and 4 feet, others are compara- tively small fishes. No less than eleven species of this genus are found in the Nile; which, together with some of the West African rivers, is likewise the home of the single representative of the genus Gymnarchus. In form the latter fish (4 nat. size), PETERS BEAKED FISH AND SLENDER PIKELET is eel-like; its jaws being armed with a series of incisor-like teeth, and its length reaching to upwards of 6 feet. Both genera are furnished with a pair of organs lying on the two sides of the tail, which are stated to be transitional in character between ordinary muscle and a true electric organ; although, if this be correct, it is difficult to conceive what can be the object or use of such a structure. Each consists of an oblong capsule, divided by vertical partitions into a number of chambers filled with a gelatinous substance. One of the species (IZ. oryrhynchus) from the Nile, is frequently depicted in the frescoes of the ancient Egyptians. SECTION ISOSPONDYLI.! THE FEATHER-Backs,—Family NOTOPTERIDA. According to the classification we are following, the whole of the remaining members of the tube-bladdered fishes form a group denominated Isospondyli, and 10n p. 333 the group Isospondyli is given as of equivalent rank with the Physostomi, of which, in the scheme here followed, it should be only a section, 476 TUBE-BLADDERED GROUP. characterised as follows. The parietal bones are completely separate; the symplectic bone, which is wanting in the group last treated of, is present; the anterior vertebrae are simple and unmodified, and both the upper and lower pharyngeal bones are separate. The group includes the least specialised of all the bony fishes, and those forming a transition to the ganoids. From the peculiar form of the dorsal fin certain fresh- and brackish-water fishes from BORNEAN FEATHER-BACK (3 nat. size). West Africa and the Oriental region, one of which (Notopterus borneensis) is shown in the illustration herewith, have received the not inappropriate name of feather-backs. They constitute a family differing from all the others in this section by the tail being tapering and fringed inferiorly by a continuation of the anal fin, as well as by the presence of a cavity in the ring-like pterotic bone, the base of the skull being double. Both the body and the head are covered with small scales; barbels are wanting; the margin of the upper jaw is formed in front by the premaxille and at the sides by the maxille; and the opercular bones are incomplete. There is no fatty fin, and the dorsal, when present, is very short, and situated in the caudal region; the pelvic pair being rudimental or wanting. The air-bladder is divided internally into several com- partments, and terminates at each end in a pair of narrow prolongations, of which the anterior ones are in communication with the organ of hearing. A further peculiarity is that the spawn falls into the cavity of the abdomen previous to its exclusion. There are two Indian representatives of the genus, one of which grows to a couple of feet in length; a third is Bornean, and the other two are West African. An extinct species has been described from the Eocene of Sumatra. THE SOUTHERN PIKELETS—Family GALAXIIDZ. For want of a better name we may designate by the name of southern pike- lets a genus of small fresh-water fishes from the Southern Hemisphere, one of which (Galaxias attenuatus) is represented in the lower figure of the illustration on p. 475. Together with the members of the next family, these fishes are dis- tinguished from the other genera of the present sectional group noticed here by having the base of the cranium simple, the tail being rounded or forked, and the ARAPAIMAS. ee pterotic bone devoid of a cavity in its interior. Externally these fishes may be recognised by the naked body and the absence of barbels; the fatty fin being absent, and the medium-sized dorsal opposite the anal. Internally the air-bladder is large and simple; and the eggs, as in the last family, fall into the abdominal cavity. Represented by rather more than a dozen species, the largest of which seldom exceeds 8 inches in length, these fish are of especial interest from a distributional point of view, since they occur in such isolated areas as New Zealand, New South Wales, Tasmania, and the southern extremity of South America. From their spotted bodies, the New Zealand representatives of the genus were formerly known as trout by the colonists. An allied New Zealand genus (Neochanna), represented by a single species, differs in the absence of pelvic fins; all the known specimens of this singular form having been found buried in burrows of clay or hard mud at a considerable distance from the water. SS oS os BRAZILIAN ARAPAIMA (5); nat. size). THE ARAPAIMAS,—Family OsTEOGLOSSID&:. Agreeing with the last family in the conformation of the base of the skull, the large tropical fresh-water fishes, which may be collectively known as arapaimas (although this name properly belongs only to the Brazilian species here figured), 478 TUBE-BLADDERED GROUP. are fully as interesting as the latter from their geographical distribution, which presents a curious general similarity to that of the existing lung-fishes, although in the present instance one of the genera has a much wider range than either of the lung-fishes. In confirmation of the northern origin of the present group, it is noteworthy that an arapaima exists in Sumatra, and also that an extinet genus (Dapedoglossus) occurs in the Eocene strata of the United States. From the preceding the more typical representatives of this family are structurally dis- tinguished by the upper pharyngeal bones being three, instead of only two in number. Externally these fishes have the body covered with large, hard scales of a mosaic-like structure; the lateral line being formed by wide openings of the mucus-canal; and the scaleless head nearly covered with roughened ossifications of the skin. The margin of the upper jaw is formed both by the premaxille and maxille, the gill- openings are wide, and false gills are wanting. The long dorsal closely resembles the anal fin, over which it is placed in the caudal region of the body; both coming very close to the tail-fin, with which they may unite as an abnormality. In structure the air-bladder may be either simple or divided into cells. The true arapaima (Arapaima gigas) of the larger rivers of Brazil and the Guianas, which is the sole representative of its genus, occupies the proud position of being the largest fresh-water bony fish, its length not unfrequently exceeding 15 feet, while its weight may reach upwards of 400 Ibs. As a genus, it is distinguished by the broad cleft of the mouth, in which the lower jaw is very prominent, and the absence of barbels, as well as by the rounded lower surface of the body, and the moderate length of the pectoral fins. In addition to an outer series of small conical teeth in the margins of the jaws, there are rows of rasp-like teeth not only on all the bones of the palate, but likewise on the tongue and hyoid bones. In spite of its enormous dimensions, the arapaima is captured by the natives of Brazil with a hook and line; its flesh being highly esteemed as food, and in a salted condition largely exported. It is also taken by being struck with an arrow, to which a line is attached; and a graphic account of this method of hunting is given by Schomburek. It appears that a party go out in a boat, and row about until a fish is sighted, when the bow and arrow are brought into requisition, and if the shot be successful, the monster is at length landed. Barbelled The four representatives of the typical genus Osteoglossum may Arapaimas. e distinguished from the last by the presence of a pair of barbels to the lower jaw, the obliquity of the cleft of the mouth, the sharp lower surface of the body, and the greater length of the pectoral fins. Of the four species the first is American, and has the same distribution as the true arapaima, the second occurs in Sumatra and Borneo, while the other two are Australian. The two latter have, however, but a very local distribution, the one (O. leichardti) being confined to the rivers of Queensland, where it is known to the natives as the barramundi, and to the colonists as the Dawson River salmon; while the second (0. jardinet), which is distinguished by the absence of a spine to the anal fin, inhabits the rivers dis- charging into the Gulf of Carpentaria. The flesh of both these species is highly esteemed as an article of food. Arapaima. Small-Mouthed The third genus of the family, which includes only a single Arapaima. snecies (Heterotis nilotica), differs from both the foregoing in having MOON-EVE AND CHISEL-JAW. 479 the pharyngeal bones numerically the same as in the southern pikelets, on which account Professor Cope regards it as the type of a distinct family. Differing from the other two genera in the comparatively small size of the cleft of the mouth, and also in the approximate equality of the length of the jaws, this fish has no barbels, and only a single series of teeth in the jaws, teeth being also present on the pterygoid and hyoid bones, but wanting on the vomer and palatines. A further peculiarity is to be found in the presence of a peculiar spiral organ on the fourth gill-arch ; and the air-bladder differs from that of the other members of the family in its cellular structure, while the stomach comprises a membranous and a muscular portion. The fish in question is found alike in the upper Nile and in the rivers of Western Africa. It grows to about 2 feet in length. Moon-EYE AND CHISEL-JAW,—Families H YODONTIDA and PANTODONTIDZ. Each of the two fishes figured in the annexed illustration is the only represent- ative not only of a genus, but likewise of a separate family ; these families agreeing CHISEL-JAW AND MOON-EYE (3 nat. size). with all the remaining ones of the present section in having the pterotie bone normal, the base of the skull double, and four upper pharyngeal bones, all of which are distinct, and the third the largest and directed forwards. In the first family the parietal bones are united, and there are two true tail-vertebre in front of the complex bone supporting the rays of the caudal fin. 480 TUBEBLADDERED GROOGP. Externally, the moon-eye (Hyodon tergisus), as the single representative of the first of the two families is popularly termed, has the body covered with cycloid scales, the head naked, and no barbels. The margin of the upper jaw is formed by the premaxille in front and the maxille at the sides, the latter bones being articulated to the former at the point of junction; and all the elements of the gill-cover are present. There is no fatty fin, and the short dorsal is placed in the caudal region, above the fore-part of the longer anal; the caudal fin being forked. The gill-openings are wide; the stomach is horseshoe- shaped, the intestine short, and the air-bladder simple; false gills being absent. In form the body is oblong and compressed, with a part of the lower surface form- ing a sharp edge; and the cleft of the mouth is somewhat oblique ; all the bones of the palate bearing small teeth, and the edges of the tongue carrying a larger series. Before their exclusion, the eges fall into the cavity of the abdomen. The moon- eye, shown in the lower figure of the cut on p. 479, grows to a length of from 1 foot to 18 inches, and is confined to the fresh waters of North America, where it is abundant in the lakes and rivers of the western side of the continent. The small fish (Pantodon buchholzi) represented in the upper figure of the cut on p. 479, was discovered not very many years ago in the rivers on the West Coast of Africa, and takes its name from the strong dental Moon-Eye. Chisel-Jaw. BEAKED SALMON (4 nat. size). armature of the jaws. Remarkably like a cyprinodont in external appearance, this fish has the body covered with relatively large scales, and the sides of the head with bony plates; the margin of the upper jaw being formed in front by the united premaxille, and at the sides by the maxille. The short dorsal fin is situated still further back than in the last genus, its front margin being considerably behind that of the rather longer anal; both the pectoral and pelvic fins are very tall, the rays of the latter forming isolated filaments, and the caudal is long and pointed, with some of its rays projecting. The muzzle is blunt, and the cleft of the mouth cirected upwards. In the gill-cover there is only an opercular and a preopercular bone, the gill-openings are wide, and the branchiostegal rays are numerous. False gills are absent; the air-bladder is simple; and the ovaries of the female, and the corresponding organs of the opposite sex, are furnished with a duct. BEAKED SALMON. 481 THE BEAKED SALMON,—Family GONORHYNCHID_E. A third fish of the present section, constituting a family by itself, is the so- called beaked salmon (Gonorhynchus greyi) from the seas of the Cape, Japan, and Australia. Agreeing with the two preceding families in the absence of a fatty fin this fish differs in having barbels to the mouth, while in the tail there is no true caudal vertebra. Both the head and body are completely covered with scales, of which the free edges are spinose ; and the margin of the upper jaw is formed entirely by the short premaxille, which are continued downwards over the maxille. The short dorsal fin is situated far back on the body, above the pelvic pair, the still shorter anal having a more posterior position; and the tail-fin is slightly forked. The gill-openings are narrow, the air-bladder is wanting, and the stomach simple. Measuring from 12 to 18 inches in length, this fish seems to be partly pelagic and partly littoral in its habits; being found in New Zealand, where it is known as the sand-eel, in bays with a sandy bottom, while elsewhere it has been taken in the open sea. In New Zealand its flesh forms an article of food. The family is also represented by an extinct genus (Vofogoneus) from the Eocene of the United States. THE SCOPELOIDS,—Family SCOPELID”. As an example of an important family of, for the most part, pelagic or deep- sea fishes, we select the so-called phosphorescent sardine, Scopelus engraulis, as being a member of the typical genus. The members of this family agree with the last in having the parietal bones united and mo true tail-vertebra, but they may be distinguished externally by the absence of barbels and the presence of a small fatty fin some distance behind the dorsal, and likewise by the want of spines on the scales, when the latter are present: some genera having the body scaled, while in others it is naked. The margin of the upper jaw is always constituted solely by the premaxille: the gill-cover may be incompletely developed; the gill-opening is wide; false gills are present; but an air-bladder is wanting. The intestine is remarkable for its shortness; and the eggs are enclosed in the saes of the ovaries, whence they are extruded by means of ducts. Containing a large number of existing genera, the family is likewise represented by several extinct types, the earliest of which dates from the Cretaceous of Istria. In the typical genus the body is oblong in form and more or less markedly compressed, with the investing scales of large size. Along the sides run series of phosphorescent spots: while similar glandular structures may in some species occur on the front of the body and on the back of the tail. The cleft of the mouth is unusually wide; the premaxillary bones being long, slender, and tapering, and the maxille well developed. The teeth are villiform, and the eye is relatively large. The pelvic fins are inserted just in front of or immediately below the line of the foremost rays of the dorsal (which is situated nearly in the middle of the length of the body), and are composed of eight rays; the fatty fin is very small; the anal is generally long; and the caudal forked. There are from eight to ten rays in the branchiostegal membrane. Dr. Giinther writes that “the fishes of this genus are small, of truly pelagic habits, and distributed over all the temperate and VOL. V.—31 482 TUBE-BLADDERED GROUP. tropical seas; they are so numerous that the surface-net, when used during a night of moderate weather, scarcely ever fails to enclose some specimens. They come to the surface at night only; during the day, and in very rough weather, they descend to depths where they are safe from sunhght or the agitation of the water, Some species never rise to the surface ; indeed, scopeli have been brought up in the dredge from almost any depth to two thousand five hundred fathoms.” Upwards of thirty species of this genus are known, and there is also an allied genus (Gyimnoscopelus) distinguished by the absence of scales. Among several other remarkable forms of the family, we may especially notice a very curious fish (/props) obtained at great depths during the voyage of the — SF ZS —— SSS ald | PHOSPHORESCENT SARDINE (nat, size), Challenger. Possessing an extremely elongate and cylindrical body, covered with large, thin, deciduous scales, this fish has a depressed head and an elongate, broad, spatulate muzzle, of which the whole upper surface is occupied by a luminous or visual organ, divided longitudinally into two halves, and representing the highly- moditied eyes. The whole length of this strange fish does not exceed between 5 and 6 inches. Another deep-sea fish (Plagyodus) is noteworthy on account of its large dimensions, and the formidable armature of its mouth; the scaleless body being long and compressed, the snout much produced, and the teeth of the jaws and palate of very unequal size, some forming long and sharply-pointed tusks. THE PHOSPHORESCENT ScOPELOIDS,—Families STERNOPTYCHIDA! and STOMATEID. More or less nearly allied to the scopeloids are two families of deep-sea or pelagic fishes usually bearing phosphorescent organs along the sides of the body ; an example of each being represented in the accompanying illustration. Silvery Light- The fish (Photichthys argenteus) shown in the upper figure of the Fish. illustration, is taken as our representative of the first of the two families, of which, in addition to the phosphorescent organs, the leading characters are as follows. The body may be either covered with thin deciduous scales, or PHOSPHORESCENT SCOPELOTIDS. 483 o entirely naked; barbels are wanting; and the fatty fin is either rudimental or of very minute size. Both the premaxille and maxille take a share in the formation of the margin of the upper jaw, and bear pointed teeth of variable length. The bones of the gill-cover are not fully developed; the gill-opening is of great width; false gills may or may not be developed; and, when present, the air-bladder is of simple structure. The ovaries are furnished with ducts. Whereas in the figured species the teeth are small, in the allied genus Chauliodus they are greatly elongated, and thus indicate highly predaceous habits on the part of their owner. Hedgehog- The members of the second family, of which the bearded Mouths. — hedgehog-mouth (Echiostoma barbatum), shown in the lower figure of our illustration, is taken as an example, may be readily distinguished from the i ull sui ‘iy Mian dy AA alg lanl i s2 SILVERY LIGHT-FISH, AND BARBED HEDGEHOG-MOUTH (4 nat. size). preceding by the presence of a long barbel to the hyoid; the skin being either naked or covered with exceedingly delicate scales, and the fatty fin (as in the figured specimen) frequently wanting. In other characters these fishes closely resemble those of the preceding family. When a fatty fin is present, as in the genus Astronesthes, the rayed dorsal is of considerable length, and placed in advance of the anal; but in the other genera both the anal and dorsal are short, and placed opposite to one another a short distance in advance of the forked caudal. In the genus represented by the figured species, the body is naked and the pectoral fins are filamentous; but in the allied Stomias there are exceedingly small scales which scarcely overlap one another. Occasionally met with floating in a helpless condition, these fishes have been dredged from depths of eighteen hundred fathoms ; and it will not escape the notice of the reader that, although dwelling in total darkness, they, like most of their allies, have well-developed eyes. On this point, 484 TUBE-BLADDERED iGROUL. Monsieur Filhol writes that “the existence of eyes in fishes which we believe to live in a dark medium, seems at first sight impossible to understand. But this fact receives an explanation when we learn that the creatures furnished with these organs are covered with a coating of luminous mucus, or bear phosphorescent plates. The phosphorescence with which the fishes of the ocean depths are endowed serves indeed both to guide them and to attract their prey, fillng for them in the latter case the same office as a torch in the hand of a fisherman. This peculiarity has been long noticed in surface-fishes which pursue their prey at night; Bennett, for instance, having described a shark which gives off a bright green phosphor- escence from the lower surface of its body. On one occasion that zoologist brought into a room a freshly-caught specimen of this shark, upon which the whole chamber was illuminated with the light given off from its body. It is probable that the different species of sharks living at moderate depths, like the one THE DORAB (4, nat, size). described by Bennett, make use of their luminosity solely for the purpose of attracting their prey within reach. In most cases the origin of this light-giving mucus must be attributed to glandular organs distributed along the flanks and tail, on the head, and more rarely on the back. There exists, however, in certain fishes, which lack these glandular organs, an apparatus of a totally different nature for the emission of light; this apparatus consisting of a kind of biconvex transparent lens closing the front of a chamber filled with clear fluid. This cavity is carpeted by a blackish membrane, formed of hexagonal cells, thus recalling the retina of the eye, and is connected with certain nerves. Phosphorescent plates of this type may be situated either beneath the eyes, or on the sides of the body,” one of the fishes thus furnished belonging to the family now under consideration, in which it forms the genus Malacosteus. A specimen of this fish captured before death had ensued was observed to emit a yellowish light from the uppermost plate beneath the eye, while that from the lower plate had a greenish tinge. In the genus Stonvas, continues our author, “the sides of the body present a double longitudinal series of phosphorescent plates, which emit light in such a manner as to cause the DORAB. 485 whole fish to be bathed in a brilliant luminous halo. This fish must, indeed, be a formidable creature to the other inhabitants of the ocean abysses; being in every way constructed and armed for strife, and its powerful teeth admirably fitted to seize and tear the flesh of the other fishes upon which it preys.” In other species (e.g. Hustomias) the barbel is greatly lengthened, all the fins form long dentated filaments; the whole of these structures being apparently modified for the emission of phosphorescent light. In our figured species not only are there luminous dots down the sides of the body, but also larger plates beneath the eyes. THE Doras,—Family CHIROCENTRIDA. With the fish represented in the accompanying illustration, which ranges from the Red Sea to the Malay Archipelago, and is commonly known in the East as the dorab (Chirocentrus dorab), we come to the first of what we may term the LONG-FINNED HERRING (} nat. size). herring and salmon group, the more typical members of which differ from the preceding families of this section in having the parietal bones of the skull separated from one another by the intervention of the supraoccipital. In common with the herrings, this fish, which is the sole representative of its family, has but a single true tail-vertebra. Externally the body is covered with thin deciduous scales ; barbels, and a fatty fin are alike lacking; but the elements of the gill-covers are fully developed. The margin of the upper jaw is formed partly by the premaxille and partly by the maxill, which are firmly welded at their junction; the short dorsal fin is situated in the caudal region of the vertebral column above the much longer anal, the tail is deeply forked, the pelvic fins are minute, the lower surface of the body is sharp, the gill-opening wide, and false gills wanting. The upward direction of the cleft of the mouth, which is armed with formidable teeth, coupled with the elongation of the lower jaw, gives a rather peculiar expression to the head, and the eyes are remarkable for being covered with skin. The stomach is furnished with a blind appendage, the intestine is short, and the air-bladder cellulated. As this fish attains a length of fully a dozen feet it is a sufficiently formidable monster, and when captured is said to bite viciously at every object 486 TUBE-BLADDERED GROUP. within reach. Its flesh is of poor quality. It has been considered that the extinet Chiromystus, from the Eocene of Brazil, may belong to this family. LonG-FINNED HeERRING,—Family BATH YTHRISSIDZ. Although its osteology has not apparently been described, we may place here the fish (Bathythrissa dorsalis) shown in the illustration on p. 485, which is another of the numerous forms in the present section representing a family by itself. Having an oblong body, with a rounded under surface, invested with eycloid seales, the head naked and devoid of barbels, and no fatty fin, this fish may be at once recognised by the great length of the many-rayed dorsal fin, which occupies nearly the whole length of the back, and is situated in advance of the short anal. There is no air-bladder, and very small eggs are produced by the ductless ovaries. This fish, which attains a length of two feet, has been obtained in Japanese waters at a depth of between three and four hundred fathoms. THE EXTINCT SAURODONTS,—Families HNCHODONTIDA, SAUROCEPHALID 2, ete. Before proceeding to the consideration of the herrings, we may briefly refer to a group of more or less closely allied extinct families, mainly characteristic of the Cretaceous period, but also represented in the lower Tertiaries. From the large size of their lanciform, reptile- like teeth, all the members of the group are collectively spoken of as the saurodont fishes. The first family (Dercetide) is typitied by the genus Dercetis, of the Chalk, and is characterised by the elongated form of the body, the large size of the teeth, which are implanted in sockets, and the presence of several rows of large triangular bony plates along the SKELETON OF A SAURODONT FISH (Hurypholis). sides of the body; the muzzle being frequently produced into a beak, and the dorsal fin single. Nearly allied is the family (Hnchodontide) represented by the widely spread Cretaceous genera Hnchodus and Lurypholis; these fishes having the body moderately compressed, and either naked or partially protected by bony plates, and the elongated upper jawbones armed (like those of the lower jaw) with small, immovably welded teeth. To a third family belongs the genus Sawrocephalus, from the North American Cretaceous, which, together with the allied forms, has the body much compressed, the large upper jaw armed with powerful teeth, usually set in sockets, and a single series of similar teeth in the lower jaw, the palatine bones being toothless. A peculiarity of the vertebrae of these fishes, with the exception of those of the neck, is the presence of two deep grooves and pits on their sides. Some of these fish attained huge dimensions; the American and Australian Cretaceous genus Portheus being distinguished by the presence of an enormous bony crest in the middle line of the skull. HERRING TRIBE. 48 ~I THE HERRING TRIBE,—Family CLUPEID.Z. Second to none in their commercial importance, the herring tribe are remark- able for the enormous number of individuals by which several of the species are represented rather than for the multiplicity of the species themselves; this being probably one of the chief reasons for the great value of these fishes as a food-supply. Although the existing representatives of the family may be readily distinguished from the salmonoids by the absence of a fatty fin, yet extinct forms indicate such an intimate connection between the two groups as to induce some naturalists to include both in a single family. Whatever may be the ultimate verdict on this point, in a work like the present, where we are mainly concerned with living types, it is obviously preferable to follow the ordinary system. While the typical representatives of the family have the parietal bones of the skull separated by the supraoccipital and but one true tail-vertebra, in the genus Elops the parietals are in contact, and there are two caudal vertebre. On this account it has been proposed to make the latter genus the type of a distinct family; a similar proposal having been made in the case of an analogous departure from the ordinary type among the salmonoids. In addition to the absence of the fatty fin, most herrings are characterised by the presence of small bony plates on the lower margin of the body. Externally the whole body is scaled, with the lateral line mostly wanting; while the head is generally naked, and the muzzle always without barbels. The under surface is more or less compressed, and generally so much so as to form a sharp edge, which is usually serrated. In the gill-cover the four elements are present, and the gill-openings are in most cases very wide. Both premaxillz and maxille enter into the formation of the margin of the upper jaw, but each of the latter bones is peculiar in being composed of three separate pieces. ‘The single short dorsal fin has a small or moderate number of weak rays, and the anal may be many-rayed. The stomach is furnished with a blind sac; the air- bladder is of more or less simple structure ; and well-developed false gills are usually present. Distributed over all temperate and tropical seas, herrings are mainly littoral fishes, none of them being inhabitants of deep water, and none truly pelagic. Although the majority are marine, many of them will enter fresh water, and some live permanently therein, while it is probable that all can be acclimatised to such conditions. As might have been expected from their generalised structure, herrings are an ancient group, the typical genus dating from the period of the Chalk, while anchovies and other existing generic types are known from the Eocene. A number of more less nearly allied Cretaceous genera appear to connect the family very closely with the higher ganoids. ; The common herring (Clupea harengus) belongs to a group of Et ad genera characterised by the equality in the length of the two jaws, the presence of free fatty lids to the eyes, and the serration of the lower border of the hinder part of the body; the typical herrings being distinguished from the allied genera by the anal fin being of moderate length, with less than thirty rays, and the serration of the under surface commencing from the chest or point of origin of the pectoral fins. Usually the seales are of moderate or large size, although they may be small; the cleft of the mouth is of medium width; and if 488 LOUBE-BLADDERIAD GROOT teeth are present at all, they are rudimental and deciduous: In position the dorsal fin is opposite the anal, and the caudal is deeply forked. Represented by some sixty species, the genus has a distribution coextensive with that of the family; but whereas the flesh of the majority of its representatives is of excellent quality, that of some tropical forms may acquire poisonous properties. In the case of such a well-known fish as the common herring it will be superfluous to give any descrip- tion; but it may be mentioned that this species may be distinguished from its allies by the presence of a patch of small ovate teeth on the vomer. It has also the dorsal fin situated exactly midway between the extremity of the muzzle, and the longest ray of the caudal fin, and the pelvic fins are directly under the dorsal. SHAD, SPRATS, AND HERRING (the shad 1, the others 3 nat. size). Whitebait are for the most part the young of this species. Common to both sides of the cooler regions of the Northern Atlantic, the herring ranges eastwards to the seas on the north of Asia. Associating in shoals numbering millions of individuals, the herring feeds upon crustaceans, worms, insects, and the young and eggs of other fishes, as well as those of its own kind. <“ During the day,” writes Mr. J. M. Mitchell, “the shoals are sometimes observable near the surface, and may be seen playing on the water, as the fishermen eall it, making a ripple,—a dark roughness similar to what we may see at the beginning of a slight breeze, this being somewhat observable without the appearance of either whales or birds. The passing near or over them of a boat or ship makes them instantly dart off in every direc- tion, leaving the appearance of long trails of light, if at night. We have been HERRING TRIBE. 489 informed by fishermen of Newhaven that the herrings take considerable flights out of the sea; off Stonehaven, in the month of September, one of these men having seen a shoal, after the spawning-season, rise up out of the water in a vast mass of many yards in extent, sparkling and flashing and flying several feet above the surface. .. On some of the coasts, as on those of Norway, the herring-shoals are frequently accompanied or pursued by numbers of whales and aquatic birds, which are all occupied in preying on them. The large dark masses of the whales rising and blowing and throwing up great quantities of the herring into the air, sparkling and glittering in the clear winter day ; the constant movements of the birds, with their shrill notes, actively engaged in seizing their easily-obtained food, vying with man in their attacks on the countless myriads of herrings, form a most wonderful sight. ... When the herrings swim near the surface, if it is calm weather, the sound of their motion is distinctly heard at a small distance; and at night their motion, if rapid, causes a beautiful bright line from the phosphorescent quality of the skin; and it is also said, that when a great body of them swims near the surface, their presence is ascertained by a strong fishy smell.” In another passage, after stating that the idea of fish migrating from the Arctic regions southwards is purely erroneous, the same author observes that “from all circumstances known of the natural history of the herring, in regard to its visits on our own coasts and the coasts of other countries, it 1s reasonable to suppose that it inhabits the seas in the neighbourhood of the coasts on which it spawns, and that it arrives at particular seasons near the coasts for the purpose of spawning, the shoals leaving the coasts immediately thereafter; and the early or late, distant or near, approach to the coast in different years, perhaps depends on the clear and warm, or dark and cold weather of the seasons, as well as upon the depth of water at the feeding and spawning-grounds.” Herrings have been kept in a brackish-water pond com- municating with the Humber, where they became dwarfed in size. The much smaller sprat (C. sprattus), so abundant on the Atlantic coasts of Europe, differs by the absence of vomerine teeth; while the shad (C. finta), shown in the upper figure of the illustration on p. 488, may be distinguished by having one or more black blotches on the sides. In this species, which not only frequents the European coasts, but ascends rivers, and is abundant in the Nile, the bony gill- rakers, of which there are from twenty-one to twenty-seven on the horizontal portion of the outer gill-arch, are short and stout. On the other hand, in the similarly spotted allice-shad (C. alosa) the gill-rakers are very long and fine, and number from sixty to eighty on the part mentioned. Both the shads are consider- ably larger than the herring. Whereas in both the herring and the sprat the opercular bone is smooth, in the pilchard or sardine (C. pilchardus) this part is’ marked by ridges radiating towards the subopercular. This species is abundant in the English Channel, the seas of Spain and Portugal, and the Mediterranean ; Vigo Bay being noted for its sardine-fishery. The following account of the sardine-fishery is taken from the Asian news- paper. “Sardines are migratory in their habits, and the exact locale of their winter quarters, despite frequent research on the point, remains a mystery. In ordinary years it is the custom for the fish to make their first appearance on the coast of Africa about the end of March, then passing northward in 490 TUBEBLADDERED GROUF. large shoals, they follow the coast of Portugal, crossing the Bay of Biscay, till they strike the coasts of Vendée in the month of April or May. Before day- break the fishing-boats leave port to search for the shoals of sardines; indeed, many leave in the evening and anchor at sea. When a peculiar bubbling of the water reveals the fish, the nets are immediately thrown. Each net is from 900 to 1000 yards in length, about 3 yards in width, and black in colour. On the upper part of the net are corkfloats, and on the lower part leaden sinkers to keep the net in an upright position. The oarsmen, generally two in number, row always either against the wind or the tide. One man casts the net as the boat advances, while ancther throws the roque into the water. This bait is an important feature of the sardine catch, as it is expensive, and fishermen often lose considerable quantities of it. It is made of the roe of cod-fish or mackerel mixed with clay, and costs from 50s. to £5, 10s. a barrel, and it 1s thrown into the water in small balls, which slowly dissolve and sink. At nightfall the boats return to port, where they sell their fish to the canners at prices varying according to the abundance of the catch and the size and freshness of the fish. Sales are made by the ‘thousand, but this term does not always indicate exactly a thousand sardines. For example, at Belle Isle 1240 fish are supposed to make a thousand. Factories for preserving sardines are located at all the ports, for the fish spoil easily and cannot bear transportation. The fishermen convey the sardines to the factories in baskets. The process of canning is as follows :—The sardines are spread on boards and salted, and the heads removed. They are then thrown into brine, where they remain half an hour. They are next washed in clean water and dried on screens. This work is done almost entirely by the wives and children of the fishermen, their united wages during the season enabling the family to subsist during the following winter. After the fish have been thoroughly dried they are cooked by dipping them for a few minutes in oil heated to 212° F. They are again drained and handed over to workmen, who pack them in small tin boxes, which are filled with pure olive oil and then soldered. The oil used is imported from the province of Bari, Italy. The boxes are next thrown into hot water, where they remain for two or three hours, according to the size of the boxes. When withdrawn, the boxes are first cooled, then rubbed with sawdust to cleanse and polish them, and packed in wooden cases of one hundred boxes for export: during their immersion in the boiling water oil will escape from all boxes not properly soldered, and in such eases the loss is sustained by the solderer, but so skilful are those in the craft that a good workman rarely misses more than two or three boxes per hundred Periodically the fish entirely disappear for a season or so from the coasts of Spain, France, and “Ttaly.” Fresh-Water Especial interest attaches to the Australian fresh-water herrings Herrings. = (Diploiystus), which differ from the typical genus in having a series of bony plates similar to those on the lower surface between the back of the head and the dorsal fin, since a similar type of fish has been long known in a fossil state, having been obtained from the Cretaceous rocks of Brazil and Syria, and the Lower Tertiary of the United States and Britain. The persistence at the present day of this ancient type of herring in the fresh waters of Australia is an instance of the survival of primitive forms of life in that region. SMOOTH-HEADS AND SOUTHERN SALMON. 491 The common anchovy of the Mediterranean (Hngraulis encras- sicholus) is the typical representative of a second widely-spread genus, with over forty species, differing from the last by the more or less nearly conical muzzle projecting beyond the lower jaw, and also by the eyes being covered with skin; while the cleft of the mouth is deep, and the tail-fin forked. In most cases each side of the body is ornamented with a broad longitudinal silvery stripe. The common anchovy is met with off the south-western coasts of England, but wanders still further to the north, and serves to supply the markets of the world. Some species have the rays of the pectoral fins produced, and thus lead on to the allied Oriental genus Coilia, in which the foremost rays of these fins are fila- Anchovies. mentous, and the exceedingly long anal fin extends backwards to join the caudal. ee A very distinct group, which, as already mentioned, is regarded by some as a distinct family, is typically represented by the two species of the tropical and subtropical genus Llops. In addition to the characters of the skull noticed in p. 487, these fish have the lower jaw longer, a thin plate of bone extending backwards from the point of union of the two branches of the lower jaw, and the whole under surface of the body smooth and rounded. The common species grows to a yard in length. An allied type (Rhacholepis) occurs in the Cretaceous rocks of Brazil. ee ee The earliest allies of the herring tribe seem to be the extinct slender-scales (Leptolepididw), of which there are a considerable number of species, ranging throughout the Jurassic period. In the typical Leptolepis the dorsal fin is placed immediately over the pelvic pair, but in the nearly allied Thrissops it is over the anal. Although there are a number of other extinct generic types, more or less closely related to the herrings, it is impossible to enter into their consideration here, and we accordingly pass on to BLACK SMOOTH-HEAD (4 nat. size), THE SMOOTH-HEADS AND SOUTHERN SALMON. Fainilies A LEPOCEPHALID.2 and HAPLOCHITONID2Z. pane a The first of these two families is typically represented by the " genus Alepocephalus, of which a species (A. niger) is shown in the annexed illustration. While agreeing with the typical salmonoids in the structure 492 TUBE-BLADDERED GROUP. of the skull and the presence of two true tail-vertebre, as well as in other features, these fish may be distinguished by the absence of the fatty fin. Whereas barbels are invariably absent, and the head is always naked, the body may be either scaled or bare. Both premaxille and maxille enter into the formation of the margin of the upper jaw, the former occupying the upper front edge of the latter. All the elements of the gill-cover are present: the dorsal fin is situated opposite the anal in the caudal region; the gill-openings are very wide; false gills are present; the air-bladder is wanting; and the curved stomach has no blind appendage. All these fish have the teeth feebly developed, the eye large, and the bones thin; while they are remarkable for their uniformly black coloration. ‘The whole of them are deep-sea tishes, with an apparently almost cosmopolitan distribution, some of them having been taken at a depth of over two thousand fathoms. Whereas the body of the typical genus is covered with thin cycloid scales, in another type the place of these is taken by fine granules. ZEBRA-SALMON. By this name may be designated two genera of fresh-water fish, constituting a family which represents the salmonoids in the Southern Hemisphere ; the zebra-salmon (Haplochiton zebra) being figured as an example of the typical genus. Like the salmon and herrings, devoid of barbels, these fish agree with the former in the presence of a fatty fin, but differ in having the margin of the upper jaw formed solely by the premaxillary bones. The body may be either naked or covered with scales: the gill-opening is wide; false gills are present ; and the air-bladder is simple. The ovaries are in the form of plates, and, in the absence of a duct, the eggs fall into the abdominal cavity. ‘The species of the typical genus, which, although devoid of scales, are externally very similar in appearance to trout, are confined to the lakes and rivers of Chili and the extreme south of Patagonia and the Falkland Islands. In South Australia and New Zealand the family is represented by the genus Prototroctes, in which the body is scaled and the jaws are armed with minute teeth; the New Zealand species being commonly known to the colonists as the grayling. Southern Salmon. SALMON FRIBE. 493 THE SALMON TrIBE,—Family SALMONID.Z. With the salmon tribe, which include the finest and “ gamest” of all fresh-water fish, we come to the last group of the true bony fishes, which may be distinguished from the preceding family by the margin of the upper jaw being formed by the pre- maxillz in front and by the maxille at the sides. As a rule, the body is scaled, while the head is invariably naked; the under surface of the body being rounded. SALMON AND SEA-TROUT (% nat. size). Inhabiting alike salt and fresh-waters, those species which spend a part or the whole of their existence in rivers or lakes are in the main confined to the Temperate and Arctic zones of the Northern Hemisphere, although one outlying genus occurs in New Zealand; and whereas the majority of the marine forms are deep-sea fishes, two genera are entirely pelagic in their habits. A considerable number of the species inhabiting fresh waters descend periodically or occasionally to the sea ; and in some cases it is perhaps rather difficult to say whether these fishes should be regarded as marine or fresh-water. All the salmonoids are remarkable for the 494 TUBE-BLADDERED GROUP. excellent quality of their flesh, which in many forms is of a more or less strongly marked pinkish hue, brought about by the crustaceans on which these carnivorous fishes so largely feed. Fossil marine salmonoids, some of which belong to existing genera, are known from the upper Cretaceous period, several of them apparently connecting the family very closely with the herrings. As mentioned above (p. 487) the more typical members of the family have the parietal bones of the skull separated from one another by the supraoccipital, but in Coregonus and Thymallus they unite together in front of it. There is, however, a genus (Stenodus) in which both conditions exist, so that there is no justification for making the union of the parietals a reason for referring Coregonus to a family apart. In all cases the supraoccipital extends forwards to join the frontals (passing beneath the parietals in the genera where those unite), and is thus quite different from the condition obtaining in the carps and characinoids. Pee aie Having the dorsal nearly or quite opposite the pelvic fins, the members of the typical genus Saliio are characterised by the small size of the scales of the body, the strong and fully developed teeth, and the presence of not more than fourteen rays in the anal fin, and of numerous blind appendages to the intestine. The cleft of the mouth is always deep, the maxilla extending up to or beyond the line of the eye. Conical teeth are present not only in the margins of the jaws, but likewise on the vomer and palatine bones, as well as on the tongue, although there are none on the pterygoids. The eggs are remarkable for their relatively large size; and the young, like those of most or all the other genera, are marked with dark crossbars. In the males the lower jaw is more developed than in the females, and at certain seasons may be developed into an upturned hook. The genus is confined to the colder portions of the Northern Hemisphere, its southern limits in the Old World being the rivers of the Hindu Kush and the Atlas range, and in America the rivers flowing into the head of the Gulf of California. Few zoological subjects have given rise to a greater amount of discussion than the life-history of the members of this genus, and the number of species by which it is represented. As regards the latter point, great difference of opinion still prevails among experts. Thus, for instance, Day considered that all the indigenous British salmonoids might be arranged under three specific types, namely, the salmon, the trout, and the charr; while other authorities admit an almost endless amount of species. The subject is not one which admits of dis- cussion in this work; and we shall accordingly confine our notice to the salmon, the typical sea- and river-trout, and the charr. As regards the variability of these fishes we may, however, quote a passage from Dr. Giinther, who writes that “these are dependent on age, sex, and sexual development, food, and the properties of the water. Some of the species interbreed, and the hybrids mix again with one of the parent species, thus producing an offspring more or less similar to the pure breed. The coloration is, first of all, subject to variation; and consequently this character but rarely assists in distinguishing a species, there being not one which would show in all stages of development the same kind of coloration. The young of all the species are barred; and this is so constantly the case that it may be used as a veneric, or even as a family character, not being peculiar to Salmo alone, but also common to Thymallus, and probably to Coregonus. The number of bars is not SALMON TRIBE. 495 quite constant, but the migratory trout have two (and even three) more than the river-trout. In some waters river-trout remain small, and frequently retain the parr-marks all their lifetime; at certain seasons a new coat of scales overlays the parr-marks, rendering them invisible for a time. When the salmonoids have passed this ‘parr’ state, the coloration becomes much more diversified. The males, especially during and immediately after the spawning-time, are more intensely coloured and variegated than the females; specimens which have not attained to maturity retaining a brighter silvery colour, and being more similar to the female fish. Food appears to have much less influence on the coloration of the outer-parts than on that of the flesh; the more variegated specimens being frequently out of condition, whilst well-fed individuals with pinkish flesh are of a more uniform, though bright, coloration. . . . The water has a marked influence on the colours; trout with intense ocellated spots are generally found in clear rapid rivers, and in small open Alpine pools: in the large lakes with pebbly bottom the fish are bright silvery, and the ocellated spots are mixed with or replaced by X-shaped black spots ; in pools or parts of lakes with muddy or peaty bottom, the trout are of a darker colour generally ; and when enclosed in caves or holes, they may assume an almost uniform blackish coloration.” A change of colour also takes place in the migratory species with the renovation of the scales, which occurs during their residence in the sea, the newly-grown portion of the silvery scales concealing the spots; and this change of coloration varies greatly according to the habitat of the individuals of some of the species. Variations of size are also common, these being for the most part dependent upon the abundance or otherwise of the food, and the extent of the area in which the fish dwell; but differences in this respect also occur among the fish hatched from the same batch of spawn, and living under the same conditions. The variations in the form and proportions of the body, and more especially in the head and jaws, according to age, sex, and season, are likewise very important, but cannot be noticed fully. The true salmon (S. salar), together with the kindred species and the trouts, belongs to a group of the genus characterised by the presence of teeth on the whole length of the vomer during at least some period of life. In the case of such a well-known fish Salmon. and also one which is generally pretty easy to distinguish from its congeners—it will be unnecessary to give a description. Dr. Giinther gives, however, certain characters by which this fish may always be identified, and among these the following may be noticed. The scales on the tail are of relatively large size, and each transverse series running from behind the fatty fin towards the lateral line contains only eleven, or occa- sionally twelve, whereas in the trouts there are from thirteen to fifteen. Secondly, the main part or body of the vomer carries a single series of small teeth, which, with advancing age, gradually disappear from behind forwards, so that half-grown and adult individuals have but a few remaining. Having a circumpolar distribution, the salmon ranges southwards in America to 41° north latitude, and in the Old World to 43°, being unknown in any of the rivers flowing into the Mediterranean. Salmon will grow to a length of between 4 and 5 feet, and commonly reach as much as 40 lbs. Much heavier fish are, however, occasionally captured. Among these may be mentioned a salmon of 60 lbs. from the Severn in 1889; one from the 496 LTUBE-BLADDERED GROG. Tay of 62 lbs. in 1891; a third of 63 lbs. from the Esk in 1890; another of 68 Ibs. from the Tay in 1893; and a fifth from the same river taken in 1870, which weighed a fraction under 70 Ibs. There is an earlier record of a British salmon of 83 lbs. weight, while a Russian is stated to have scaled upwards of 93 Ibs. For the following brief sketch of the life-history of the salmon, we are indebted to a paper by Mr. G. Rooper, from which the following extracts, with some verbal alterations, are taken. After mentioning the well-known periodical migration of salmon, the writer observes that the eggs are deposited by the female “some time during the winter months, in beds of gravel over which a rapid stream flows, principally in the upper reaches of the river, where the water is more aérated and free from pollutions of any sort—since clay, earth, or any extraneous substance would choke and destroy the embryo fish. Indeed, from the time of entering the river, the object of the fish seems to be to arrive at its source. Until they have spawned they never descend, but, resting at times in favourite pools, continually struggle upwards. Only the late fish spawn in the lower waters. To such as have only seen the salmon in prime condition, the appearance of the fish when on the eve of spawning would come as a surprise. The female is then dark in colour, almost black, and her shape sadly altered for the worse from that which she presented when in condition. As for the male, he is about as hideous as can well be imagined, his general colour being a dirty red, blotched with orange and dark spots. His jaws are elongated, and the lower one furnished with a huge beak, as thick, and nearly as long as a man’s middle finger; while his teeth are sharp and numerous, and his head, from the shrinking of the shoulders, appears disproportionally large. His skin also is slimy and disagreeable to handle, and, in fact, scarcely a more repulsive creature in appearance exists. Arrived on the spawning-ground the female, then called a baggit, alone proceeds to form the nest, or ‘redd’ as it is termed. This she eftects by a sort of wriggling motion of the lower part of her body working on the loose gravel. Many authors state that this is effected by the action of the tail, but I think the convex formation of the body at that period would prevent the tail touching the gravel, unless the fish stood at an angle of 45°,in which case the stream would carry her down. The redd, a deep trench, being formed, the female proceeds, attended by the male fish—frequently by two kippers, as they are then called—to deposit her eggs. This she does, not all at once, but in small quantities at intervals, frequently returning to the redd for the purpose. The eggs are at once fecundated by the milt of the kipper; this process going on for two or three days, the fish sinking down occasionally into the pool below to rest and recover their strength. The effect of the fertilisation of the ova is to add greatly to their specitic gravity ; the eggs sink, and are at once covered with gravel by a similar motion on the part of the baggit to that used in the formation of the redd. Here, the process being completed, the eggs remain during a period of from one hundred and twenty to one hundred and forty days, according to the temperature of the water. At the expiration of that time, the little fish come into existence, and, after a few days, wriggle out of their gravelly, bed and seek refuge under an adjacent rock or stone, where they remain in safety for some twelve or fourteen days longer. The appearance of the young fish at that time gives little promise of the beautiful SALMON TRIBE. 497 form to which they subsequently attain. They are indeed shapeless little monsters, more like tadpoles than fish, each furnished with a little bag of nutriment forming a portion of the abdomen. On this, for two or three weeks, they subsist, until it is absorbed, when they take the form of fishes. They are then about 1 inch in length, and are known as salmon-fry or samlets. A portion of the eggs are washed down the stream during the process of spawning, and become the prey of trout and other fish which attend the redds for the purpose of feeding on them. In this they do no harm whatever, for these eggs, being uncovered and unfecundated, could never arrive at maturity. The kippers, when not actually engaged in the spawning process, swim rapidly about the redd, fighting fiercely with one another. ‘The use of the beak appears then to come into operation. Many authors erroneously describe this beak either as a weapon of offence, or as a sort of pickaxe used in digging out the redd; but it seems to me that nature has provided this singular excrescence as a protection and safeguard against the savage attacks made on each other. So large is its size, and so closely does it fit into the hole or socket formed in the upper jaw, that it would appear almost impossible for the fish even to open his mouth; but he does so, to some extent at least, and with its cat-like teeth inflicts deep, and sometimes dangerous wounds on his antagonists. As to its alleged use as a digging implement, the substance of the beak is cartilaginous, not horny, and by no means hard; it would be worn down in the process of digging in ten minutes, and, moreover, the female alone prepares the redd. After leaving the stone or rock under which it has sought protection, the young fish grows very rapidly, as is natural in one destined to attain such huge dimensions as the salmon. In the course of a month or six weeks the fry have attained to the length of 4 inches, and are then called ‘parr’; when they bear conspicuously on their bodies transverse marks or bars, which are common to the young of every member of the salmon family. Unfortunately, there is another little fish, a humble relation of the lordly salmon, also barred, very similar in appearance, which too is called a parr, and the identity in name and similarity in appearance has occasioned great confusion and controversy, especially as they are inhabitants of the same waters, and affect to some extent each other’s company. The time of their remaining in the parr stage is also a subject of dispute; and while some say two, three, or sometimes four years, my opinion is that they remain one year only. In the second April of their existence a change in the appearance of the parr occurs, which assumes the silvery scales of the adult fish, wearing his new apparel over his old barred coat. He is now called a ‘ smolt, and perhaps, with a wish to exhibit himself in his new and beautiful apparel, evinces a daily increasing restlessness and desire to quit his home. With the first floods in May myriads of these lovely little fishes start on their downward journey toward the sea. It is a beautiful sight to watch they movements when descending ; and for many days the river teems with them, not a square foot of water being without one when the stream is at all rapid. As fry the smolts were exposed to many dangers, but they were nothing to those which beset them as parrs on their journey towards the sea. Their enemies are legion. Trout and pike devour them; gull swoop down and swallow them wholesale. Herons, standing mid-leg deep in the water, pick them out as they pass; and even their -OL..V.— 22 498 TUBE-BLADDERED GROUF. own kindred devour them without seruple. Unluckily,. too, for them, a certain number of great, hungry kelts (as the fish are called after spawning), having recovered to a great extent their condition, accompany them on their seaward journey, and prey upon their young companions as they travel; and I believe that a hungry kelt will devour upwards of forty or fifty smolts in a day. Arrived at the sea, the little fish are met by a fresh array of enemies. The army of gulls is always with them, and these are reinforced by cormorants, divers, and other sea-birds, besides which shoals of ravenous fish await their arrival, and assist in thinning their ranks. It is wonderful that any should escape, and, but for the extraordinary fecundity of the salmon, they would speedily be annihilated; but such is their prolific nature that a remnant always survives to return to the spawning-beds and keep up the supply. Buckland calculated that the number of egos laid by a salmon was about one thousand to the pound weight, a fish of 15 lbs. therefore producing fifteen thousand eggs. The food of the smolt during his sojourn in the sea is abundant, consisting chiefly of sand-eels, molluses, and marine insects. ‘The smolts increase accordingly very rapidly in size, and in three or four months the fish that came down 5 or 6 ounces in weight returns to the river from whence he came, a grilse of from 4 to 6 Ibs.; the grilse being the fifth stage of the salmon’s existence. Unless accidentally prevented the grilse always returns to the river from whence it came, and after spending the autumn and winter at home, and providing for the continuance of the family by spawning, as already described, returns as a kelt to the sea in the following year, reappearing the next as a salmon of at least 10 or 12 Ibs. weight. It should be added, that, after spawning, the fish speedily recover their colour, and to a great extent their condition ; the baggit at once losing her dark complexion, and the kipper disearding his hideous livery, his great beak being rapidly absorbed, his sides becoming silvery, and his back assuming a dark bluish tinge.” With reference to the statement in this account that salmon always return to the river of their birth, it may be observed that although this is generally the case, the circumstance that salmon occasionally make their appearance at the mouth of the Thames and other rivers which they have ceased to inhabit, shows that there are exceptions to the rule. The obstacles that salmon will surmount in their ascent of rivers during the return from the sea are too well-known to require notice; but it is probable that the height to which they can leap has been exaggerated. The period of spawning varies with the country, taking place in the south of Sweden and North Germany at the latter part of October or early in November; while in Denmark it may be deferred till February or the beginning of March; November and December being the usual spawning-months in Scotland. In spite of their diversity of habitat, and likewise of coloration and structure, Day is of opinion that the migratory sea-trout, or salmon-trout (S. truttw), and the stationary river-trout (S. fa7rio), as well as the various forms from the British lakes, are nothing more than varieties of a single Trout. variable race ; and it must be confessed that no one has hitherto been able to define all the nominal British species with anything like definiteness. Still, however, in the modern sense of the words there is no possibility of drawing a hard-and-fast SALMON TRIBE. 499 line between a species and a variety; and the question is accordingly of no very great importance one way or another. Some of the characters distinguishing the salmon from the trout have been already indicated on p. 494; and it will suffice to note very shortly some of the reasons given by Day for regarding all the British trout as referable to a single species. It is well known that sea-trout—as represented not only by the typical form, but likewise by the so-called sewen (S. cambricus) of the Welsh rivers—are silvery in colour, with black spots during their sojourn in the sea; when, however, they enter the rivers for the purpose of spawning, an orange margin appears on the upper and lower edges of the caudal, MAY-TROUT AND HUCHO (54 nat. size). and likewise on the fatty, fin; while spots of the same colour show themselves on the body. On the other hand, the nonmigratory forms may be arranged under two types of coloration, some loch-trout (which may have been originally migratory, but are now landlocked) being mainly silvery during the smolt-stage, and subse- quently golden and spotted; while the estuarine, lake, and river-trout are all golden, with purplish reflections, and more or less fully marked with black and vermilion spots. It appears, indeed, that a long residence in fresh water generally leads to the disappearance of the silvery sheen characteristic of the salmonoids while in the sea (and which is probably their primitive type of coloration), and to the promotion of colour. As a partially transitional type between sea-trout and 500 TUBE-BLADDERED GROUP. river-trout may be taken the Lochleven trout, which is somewhat silvery during the smolt-stage, with the spots generally black, and no orange border to the fatty fin, but at a later stage assumes the general coloration of the river-trout, although lacking the white black-based front margin to the dorsal, anal, and pelvic fins characteristic of the latter. Silvery trout do, however, occasionally occur in fresh waters, where there is no possibility of their having migrated from the sea. In concluding his observations concerning the coloration of trout, Day writes that “yeasons have been shown for admitting that sea-trout might breed in fresh waters without descending to the sea. That they can be traced step by step, and link by link, into the brook-trout, and vice-versa ; that the Lochleven trout, which normally possesses a smolt- or grilse-stage, passes into the brook-trout; and also that breeding any of these two forms together sets up no unusual phenomena.” Later on, he observes that some of the chief distinctions between the sea- and fresh-water forms of trout consist in the comparatively more complete system of dentition in the fresh-water races, their generally longer head, blunter muzzle, and stronger upper-jaw, irrespective of the smaller number of blind appendages to the intestine. The dentition is, however, excessively variable; and specimens with the coloration and form of the river-trout taken in estuaries, or even in the sea, usually have the small number of vomerine teeth characteristic of the migratory forms; while, on the other hand, fresh-water examples with the coloration of the migratory type, may have a dentition of the nonmigratory type. “It has been asserted that brook-trout invariably have a double row of teeth along the body of the vomer, and some authors have gone so far as to assert that these teeth are not deciduous. Doubtless it is not uncommon to find trout up to 2 lbs. weight, or even more, with all the vomerine teeth thus remaining intact when a double row is present; but it is by no means rare to see only one irregularly-placed row, while in very large specimens these teeth (unless they have entirely disappeared) are always in a single row, and the vomer may be found toothless, or with only one or two teeth at the hinder edge of the head. Equally incorrect is the statement that the teeth disappear differently in different forms, for in all they first assume a single row, and then fall out, first commencing from behind. But in the rapidly growing sea-trout the vomerine teeth are shed sooner than in the brook-trout.” The limits of our space preclude our entering further into the consideration of this interesting subject. The ordinary sea-trout, which is essentially a North-European fish, much more common in Scotland than in England, and grows to a length of 3 feet, is depicted in the lower figure of the illustration on p- 493; while, as an example of a spotted form, we take a variety of the Continental lake-trout (S. lacustris), shown in the upper figure of the illustration on p. 499. Known on the Continent as the mazforelle (May-trout), this fish has the sides of the body marked with irregular angular or X-shaped black spots, between which are red spots, these spots becoming less numerous beneath the lateral line, while the under surface may be tinged with red. On the gill-cover the spots are larger and more rounded. In the typical variety of this trout, from the Lake of Constance, the spots do not extend below the lateral line; this form being known as the schwebforelle. The migrations of the sea-trout are very similar to those of the salmon; in Sutherland the great run of these fish to the sea taking place in June, while they reascend SALMON TRIBE. 501 the rivers in autumn to spawn. Jardine writes that “in approaching the entrance of rivers, or in seeking out, as it were, some one they preferred, shoals of this fish may be seen coasting the bays and headlands, leaping and sporting in great numbers, from 1 to 3 or 4 Ibs. in weight; and in some of the smaller bays the shoals can be traced several times circling it, and apparently feeding.” On the other hand, the Continental May-trout spends the colder months in the deepest waters of the mountain-lakes, only coming to the surface in May. During the summer these trout may be seen swimming round the shoals of small fishes on which they prey until they get them well together, when they make a sudden rush among them. Much the same difference of opinion as obtains with regard to the number of species of trout exists in the case of charr, Charr. GRAYLING AND CHARR (¢ nat. size). Dr. Giinther recognising five British lacustrine species, which he regards as distinct from S. wmbla of the Swiss lakes; while Day includes the whole of these under the latter, which is also taken to embrace the sebling (S. salvelinus) of the mountain-lakes of Bavaria and Austria, as well as the migratory northern charr (S. alpinus), ranging from Lapland and Seandinavia to Iceland and the northern parts of Scotland. All charr differ from salmon and trout in having the teeth at all ages confined to the head of the vomer, instead of being distributed over its whole length; and all the forms mentioned above, which have a very uniform 502 TUBE-BLADDERED GROUP. type of coloration, agree in having median teeth on the hyoid bone. Without cominitting ourselves definitely, we confess that we are inclined to agree with Day as to the specific identity of the whole of them. ‘To illustrate the group, we have the sebling depicted in the lower figure of the illustration on p. 501. In the spawning-season the upper-parts of this fish are brownish green, and the sides lighter; the under surface passing through all shades of orange to vermilion, from the throat to the pelvic fins, where the colour attains its greatest intensity. The sides are ornamented with rounded spots varying from white to red in colour ; the dorsal fin has dark markings, and the pectoral and pelvic fins are brilliant red. This form commonly grows to a length of 8 or 9 inches, but the northern charr attains much larger dimensions. Day writes that “the colours of the British charr do not vary to so great an extent as in the trout, owing to their residing in deeper waters, and usually merely ascending towards the surface at night-time to feed, while other changes in tint are consequent upon the breeding-season. In the Lakes of Cumberland, Westmoreland, and Lancashire this fish in its ordinary state is the case-charr of Pennant; when exhibiting the bright crimson belly which it assumes before spawning, it is called the red charr; when out of season, the spawn having been shed, it is distinguished by the name of the gilt charr. Charr are a more delicate and apparently shorter-lved fish than trout, requiring deeper and stiller pieces of water, and a colder temperature; they have even been recorded as residing in lochs where the sun never reaches the surface of the water. They are readily destroyed by poisonous substances; while attempts to introduce them to fresh localities have not been so uniformly successful as with the trout.” The North American charr (S. fontinalis), which has been successfully intro- duced into British waters, together with the hucho (S. hucho) of the Danube, difter from the foregoing in the absence of median teeth on the hyoid bone; the latter fish being shown in the lower figure of the illustration on p. 499. The general colour of the American charr is greenish,—lghter above than beneath,—beautifully shot with purple and gold, ornamented with numerous dark spots above, and fewer below the lateral line, many of which in front of the dorsal fin coalesce into streaks, and also with red spots above the aforesaid line. Most of the fins have dark markings; and in the breeding-season the male assumes a black line along the under surface. These fish usually range in size from 2 to 3 Ibs., although they may be larger. The hucho, on the other hand, which is readily characterised by its elongated, slender, and almost cylindrical form, attains dimensions equal to those of the salmon. Many-Rayed A group of migratory salmonoids (Onchorhynchus) mhabiting the Salmon. North American and Asiatic rivers flowing into the Pacific differ from the typical genus in having more than fourteen rays in the anal fin; while their kelts are remarkable for the degree to which the jaws are hooked, and the humping of the back. An early writer in describing the hordes in which these salmon annually visit Kamschatka, states that they “come from the sea in such numbers that they stop the course of the rivers, and cause them to overflow the banks; and when the waters fall there remains a surprising quantity of dead fish upon the shore, which produces an incomparable stink; and at this time the bears and dogs catch more fish with their paws than people do at other places with their SALMON TRIBE. 503 o nets.” Dr. Guillemard adds that “every year the various kinds of salmon arrive at the mouths of the Kamschatkan rivers with surprising regularity. The date of the advent of these different species extends from May to mid-August; but each has its own time of arrival, which, from its constancy, appears to be more or less independent of seasonal influences. A few fish apparently remain at or about the river mouths during the summer, and eventually return to the sea, but these are so few as to be scarcely worthy of mention. The vast majority—practically all, in fact—ascend the streams to spawn, and, having once done so, die. In the case of some species every fish appears to perish; in others, a few get back to the sea.” The Oriental salmon (0. orientalis) of Kamschatka commonly grows to a weight of from 50 to 60 Ibs.; and the flesh is said to be superior in flavour to that of any other member of the family. The beautiful and delicately flavoured little fish known as smelts melts. : : - : are represented by three species, one of which (Osmerus eperlanus) is COMMON SMELT (} nat. size). an inhabitant of the seas and many fresh waters of Northern and Central Europe, while the second (0. viridescens), which is perhaps only a variety, is confined to the opposite side of the Atlantic, and the third (0. thaleichthys) is found on the coasts of California. These fish form a kind of connecting link between the salmon and its allies and the under-mentioned Coregonus, but internally differ from both, the appendages to the intestine being short and few in number, and the egos small, while the teeth are strongly developed. The scales are of moderate size: the cleft of the mouth is wide, with the maxillary bone extending nearly or quite to the hinder margin of the eye; the teeth of the upper jaw are much smaller than those of the lower; the vomer is armed with a transverse series of teeth, several of which are tusk-like; the palatines and pterygoids bear conical teeth ; 504 TUBE-BLADDERED GROUF. while there are also tusk-like teeth on the front of the tongue, and several longitudinal series of small ones on the hinder part of the same. In length the pectoral fins are medium. Growing to a length of 7 or 8 inches in the sea, the common smelt is also found in rivers and landlocked lakes, where its size is always considerably less. The allied candle-fish (Thaleichthys), of the Pacific coasts of North America, distinguished by its rudimental teeth, has flesh of such an oily nature that it can be burnt as a candle, although it is hkewise used as food. For want of a collective English name, we must allude by a modification of their Latin title to an extensive group of mostly fresh-water salmonoids, among which the powan (Coregonus clupeoides), the vendace (C. vandesius) of Lochmaben, and the pollan (C. pollan) of the Irish lakes, are well-known British forms. In these fish the scales are not strikingly large ; Coregonoids. the cleft of the mouth is of moderate size, with a broad maxilla, either short or of medium length, and not extending beyond the front margin of the socket of the eye; while the teeth, if present at all, are minute and deciduous, in the adult usually remaining only on the tongue. The dorsal fin is not over long, and the caudal is deeply forked. Whereas in the small size of their eggs these fish resemble the smelts, they differ in having about one hundred and fifty blind appendages of nearly uniform length attached to the intestine. As already mentioned, these fish differ from the typical salmonoids in the relations of the bones on the top of the skull, on which account they are regarded by Professor Cope as indicating a separate family. Represented by over forty species, ranging over Northern Temperate Europe, Asia, and North America, core- gonoids are for the most part entirely fresh-water fishes, although a few make periodical migrations to the sea, while the European schneepel (C. oxyrhynchus) is as much a marine as a fresh-water fish. Local in their distribution in Europe, although as many as three different species may inhabit the same lake, coregonoids are extremely abundant in all the fresh waters of North America (where they are commonly known by the name of white-fish); and whereas all the British forms are small, some of the continental species may attain a length of fully two feet. The genus may be divided into groups, according to the conformation of the muzzle and jaws. Of these, the first is represented solely by the schneepel (C. oryrhynchus), which frequents the coasts and rivers of Belgium, Holland, Germany, and Sweden, and occasionally wanders into British waters. It is easily distinguished by the production of the extremity of the upper jaw into a conical fleshy snout projecting beyond the lower, while its scales are more or less nearly circular. In length, this fish grows to a foot and a half. Asan example of the group in which the muzzle is obliquely truncated, with the nose projecting, we may take the marane (C. lavaretus), shown in the lower figure of our illustration; this fish being widely distributed in the lakes of the Continent, where its flesh is highly esteemed as food. Whereas in the Austrian lakes this fish does not exceed 14 or 15 inches in length, with a weight of half a pound, in Lake Constance it grows to a couple of feet in length, and from 4 to 6 lbs. in weight. Living at great depths, this fish feeds on worms, insects, and water-snails. While the powan belongs to another group characterised by the vertical truncation of the muzzle, the pollan and vendace are assigned to yet another division in which the lower jaw is longer than the upper, SALMON TRIBE. 505 into a shallow notch of which it is fitted. Asa representative of this latter group we take the pigmy marane (C7. albula) of Northern Europe, shown in the upper figure of the illustration. Pollan, which grow to a length of about 6 inches, are largely sold in Belfast during the spawning-season, at which time they come up from the deep waters of Lough Neagh to the shallows. At times they occur in enormous numbers, upwards of seventeen thousand having been taken on one occasion in the early part of this century. PIGMY MARANE AND MARANE (3 nat. size). Peskiioes The last of the salmonoids that we have space to notice are the erayling, of which the European species (Thymallus vulgaris) is shown in the upper figure of the illustration on p. 501. Nearly allied to the coregonoids, the grayling are readily distinguished by the greater height and length of the dorsal fin, which includes from thirteen to twenty-three rays. The cleft of the mouth is also smaller, and the maxilla of small size. Small teeth are present in the jawbones, as well as on the palatines and the head of the vomer, but they are wanting on the tongue. The blind appendages of the intestine are less numerous than in either the salmon or the coregonoids, and the air-bladder is unusually large. The range of the genus includes a large portion of Europe, Northern Asia, and the colder regions of North America. The common species is found locally over a great part of Europe, ranging from Lapland to Venice, and from England to Russia. It is, however, unknown in Ireland, and has only been introduced of late years into Scotland; while in England it is most abundant in the rivers flowing from the limestone Pennine chain in the north, and the Red 506 GANOIDS. Sandstone districts of the central counties, and likewise in the chalk streams of the south. In the latter area grayling occasionally run to nearly 4 lbs. in weight, but in Northern Scandinavia they may reach | lb. more. In Switzerland they are found in Lake Constance and other large pieces of water. An elegantly-shaped fish, the grayling varies considerably in colour according to the season of the year, the back being generally greenish brown, passing into grey on the sides, while the under-parts are silvery. The sides of the head are yellow, with black spots, which also occur on the fore-part of the body; and brownish grey longitudinal stripes run in the direction of the rows of scales. The pelvic and anal fins are violet, frequently marked with brown crossbars; the pectorals are yellow, turning to red in the breeding-season ; while the black-bordered dorsal and caudal are generally red, although sometimes blue; the former, and sometimes also the latter, being ornamented with longitudinal dark bands or rows of spots. A second species, with smaller scales, inhabit the mountain streams of Dalmatia, but the other two are North American. A remarkable fish from the fresh waters of the United States known as Percopsis guttata, which has the general characters of a salmonoid but the mouth and scales of a perch-like type, is regarded as represent- Percopsis. ing a family (Percopsidw) by itself, nearly allied to the salmon tribe. THE Bony PIKE AND ITs KINDRED,—Suborder Aitheospondyli. The remaining groups of the Teleostomous fishes exhibit a more or less decidedly lower type of organisation than those described above ; and, although the sturgeons are still well represented, these groups as a whole are evidently waning ones at the present day, having only very few living forms, whereas in past epochs some of them formed the dominant types in the fish-fauna of the world. The bony- pikes of the fresh waters of North America constitute a family (Lepidosteide) which forms the sole existing representative of a distinct suborder. While agreeing with the preceding suborders in the divisional characters mentioned on p. 334, the members of this group and the next exhibit much more marked differences from all the foregoing groups than do the latter from one another. With the exception of the extinct spear-beaks, the tail is of the abbreviated heterocercal type ; that is to say, that while its fin is more or less nearly symmetrical, the vertebral column, which retains its primitive tapering extremity, runs in the upper half. The scales are ganoid, and very frequently quadrangular, although they may be rounded and distinctly overlapping. In the living represen- tatives of both suborders the air-bladder is connected with the cesophagus by a duct, in the same manner as in the tube-bladdered fishes; but the optic nerves simply cross one another, without any interlacing of their fibres, and there is a spiral valve to the intestine. Whereas, with the exception of one extinct group of herrings, the whole of the suborders of bony fishes hitherto noticed are unknown previous to the Cretaceous epoch, members of the two groups to be now considered were abundant in the antecedent Jurassic period. The group including the bony-pike may be distinguished from the next by the full ossification of the internal skeleton; the scales being always of the typical BONY-PIKE. aos / quadrangular ganoid type, and the branchiostegal rays having no in advance of them. gular plate As a family, the bony-pikes, of which the common species (Lepidosteus osteus) is shown in our illustration, are distinguished from all other fish by having the bodies of the vertebree convex in front and con- cave behind, instead of having both surfaces cupped. The fins are furnished with fulcra, the dorsal and anal consisting of soft rays only, and placed far back, and near the caudal, which is of the abbreviated heterocereal type ; while the trunk is much longer than the abdominal portion of the vertebral column, and the bran- chiostegal rays are comparatively few, and have not an enamelled outer surface. In form, the body of the bony-pikes is elongate and subcylindrical; the long muzzle is either spatulate or beak-shaped: the cleft of the mouth wide; and both Existing Family. BONY-PIKE (4 nat. size). the palate and jaws are armed with bands of rasp-like teeth, and also with larger conical ones. There are four gills and three branchiostegal rays on each side ; and the air-bladder is cellular. Bony-pike, of which there are three existing species, are now confined to North and Central America and Cuba; but they are repre- sented in the European Eocene, and by allied extinct genera in the Eocene and Miocene strata of the United States, one of these also occurring in the French Eocene. The existing forms grow to a length of 6 feet, and are carnivorous, feed- ing upon smaller fishes. They are often known by the name of gar-pike, although, as mentioned on p. 400, that title is best restricted to a totally different group. The extinet Jurassic spear-beaks (Aspidorhynchus) constitute a second family (Aspidorhynchide), distinguished by the normal structure of the vertebre, the homocercal tail, and the production of the upper jaw ; the general form of the body and the arrangement of the fins being very similar to that obtaining in the bony-pike. Spear-Beaks. 508 GANOIDS. THE Bow-FIN AND ITs ALLIES,—Suborder Protospondyli. The so-called bow-fin (Ama calva) of the fresh waters of the United States is the sole existing representative of a second and larger subordinal group, differ- ing from the last by the imperfect ossification of the skeleton, the notochord being either persistent throughout life, or if more or less completely replaced by vertebre, those in front of the caudal region have their bodies composed of three distinet elements (pleurocentra and intercentrum), which remain separate and alternating even when fully developed. The lower jaw is complex, and composed of several pieces ; in the pectoral arch the infraclavicular plate is absent; and the pectoral fin has more than three basal elements belonging to the true internal skeleton; while the tail is always abbreviated heterocercal. THE BOW-FIN (1 nat. size). Together with three extinct genera, the bow-fin constitutes a family (Amiide) characterised as follows. The lower jaw has its suspending arrangement directed backwards, and the cleft of the mouth is wide; the degree of ossification of the vertebre is variable, although these often form complete discs; the body is elongate or fusiform; the margins of the jaws are armed with an outer series of large and conical teeth, internally to which are smaller ones; fulcra to the fins are either wanting or of minute size; and the dorsal fin is of variable, although usually of considerable length. Having the scales thin, somewhat rounded, and overlapping, the bow-fin represents a genus in which there are no fulera, and the long dorsal fin occupies three-fourths the length of the body, while the anal fin is short, the caudal rounded, and the throat furnished with asingle gular plate, followed by a number of branchiostegal rays. The single existing species of the genus, which attains a length of 2 feet, is confined to the fresh waters of the United States, where it is exceedingly abundant in some of the Existing Family. THE BOW-EIN. 509 northern lakes, but remains of extinct species have been obtained, not only from the Eocene rocks of the same country, but likewise from the upper Eocene and Miocene strata of Europe. Carnivorous in its diet, preyimg both upon other fish and also upon aquatic crustaceans and insects, the bow-fin is capable of living for fully an hour out of water; and when in its native haunts, especially where the water is foul, comes frequently to the surface to breathe, rising to the surface, and taking in large mouthfuls of air without the emission of a single bubble. When near the surface, this fish often utters a bell-like note, probably due to the passage of air from the air-bladder. The breeding-season, during which the colours of the fish are more brilliant, lasts from May till the beginning of June. The bow-fins breed among floating islands of herbage fringing the great lakes. Here they lay thousands of minute eggs on the water-plants which form the base of a series of tunnels, composed partly of root-fibres, and partly of a moss-like growth. Of the nest thus formed, the male fish takes entire charge till the fry are hatched; the development of the eggs being unusually rapid. The embryos, while agreeing in many respects with those of the typical ganoids, are stated to approximate in other points to those of the higher bony fishes. Megalwrus, from the upper Jurassic, is an allied extinct genus with a short dorsal fin and fulera; while the Jurassic Eurycormus and Liodesmus likewise belong to the same family. Among several extinct families of which the members are mostly Extinct Families. of Jurassic age, we may notice the Pachycormide, as represented typically by Pachycormus, im which, while the body and jaws have the same form anc structure SKELETON OF AN EXTINCT AMIOID (Caturus). as in the bow-fish, the notochord is persistent, and the ethmoid bone fused with the vomer to form a long beak; the fin-rays being slender and closely set, the dorsal fin short, and fulera absent or minute. Hugnathus and Caturus are well-known members of a third family distinguished by the vertebrxe being usually represented by incomplete rings, by the large fulera, and the short dorsal fin; the caudal fin being forked. The Pyenodonts, ranging from the Lias to the Eocene, constitute another family group, in which the body is either deeply fusiform or rhomboidal; the notochord has no ossification around it; the cleft of the mouth is narrow ; the teeth are small, nodular, and aggregated into a pavement, without vertical successors ; the gill- cover is of a very simple type; branchiostegal rays and fulera are alike absent; and the dorsal fin is elongated. The family is typically repre- sented by the genus Pycnodus; but we have fioured as an example of the dentition the lower RIGHT HALF OF THE LOWER JAW OF A 2 i A pycnopont (Mesodon).—After Gaudry. jaw of the allied Mesodon. Yet another family 510 GANOIDS. (Dapediidw) is represented by Dapedius, Lepidotus, and several other allied genera, In which the body is more or less deeply fusiform, the suspensory apparatus of the lower jaw either vertical or inclined forwards, the cleft of the mouth narrow, the teeth cylindrical or in the form of button-like knobs, the vertebra not more than rings, and the dorsal fin not ex- tending more than half the length of the body. In this family the teeth have vertical suc- cessors; and while some of the earlier THE GIANT SCALE-TOOTH, WITH A DETACHED SCALE AND TEETH genera date from (much reduced). the Trias, the sceale- tooths (Lepidotus), of which an example is figured in the illustration, survived till the Chalk. Some of the species of this genus attained very large dimensions ; and their remains are beautifully preserved in the Lithographic Limestone of Bavaria. In all these the seales are of the typical quadrangular ganoid type. THE STURGEON-TRIBE,—Suborder Chondrostei. This important suborder brings us to the last group of the fan-finned fishes (Actinopterygii), which forms a division by itself differmg in several important particulars from the one including the whole of the foregoing suborders ; the more important characters of the first division having been given on p. 334. Whereas in that division the number of dermal rays in the dorsal and anal fins is equal to the supporting elements in the true internal skeleton, in the present division the dermal rays are more numerous than their supports. Then, again, whereas in the former division the pelvic fins have their superior row of supporting ossicles, or baseosts, rudimental or wanting, in the present group these are well developed. The living representatives of the sturgeon tribe agree with the bow-fish and its allies in the want of any interlacing of the fibres of the optic nerves at their crossing, and likewise in the presence of a spiral valve to the intestine. In both the living and extinct types the tail is of either the diphycercal or heterocereal type. As a suborder, the sturgeon tribe may be characterised by the more or less completely persistent notochord, by the inferior and superior supporting ossicles (axonosts and baseosts) of the dorsal and anal fins forming a simple and regular series, and also by the presence of a pair of infraclavicular plates in the pectoral girdle. In all the known forms there is a single dorsal and anal fin, both of which are well separated from the caudal; while in the existing members the air-bladder is fur- nished with a duct. Although represented at the present solely by the sturgeons and their allies, the group was very abundant during the Secondary epoch: and whereas the sturgeons, together with certain extinct families, form what may be termed a degenerate specialised series characterised by the absence of ganoid scales in a second and normal series the body was covered with such scales. vs i ! Ways " GIANT AND COMMON STURGEON, 7: & STURGEON TRIBE. 513 Toothed The toothed sturgeons, of which there are two existing repre- Sturgeons. sentatives, each forming a genus by itself, constitute the family Polyodontide. While agreeing with the other members of the series in having the cartilaginous skull invested with a series of superficial bony plates, these fishes are specially distinguished by possessing a median unpaired series of bones in this shield; by the absence of branchiostegal rays; the presence of minute teeth in the adult; the heterocereal tail; and by the skin being either naked or with some scales on the upper lobe of the tail. The first of the two existing genera is represented by the spoon-beaked sturgeon (Polyodon folius) of the Mississippi, which grows to a length of 6 feet, and is characterised by the production of the upper jaw into a very long spoon-like beak, with thin, flexible margins, equal to one-fourth the SPOON-BEAKED STURGEON (;/; nat. size), total length in the adult, but still longer in the young. The gill-cover ends in a long tapering flap; the upper lobe of the tail bears a numerous series of narrow fulera; and the air-bladder is cellular. On the other hand, the slender-beaked sturgeon (Psephurus gladius) from the Yang-tse-kiang and Hoangho rivers of China, differs in the more conical form of the beak, and in the large size and small number of the caudal fulera. Growing to an enormous length—it is said as much as 20 feet—this fish agrees with the preceding in the very small size of its eyes, from which it may be inferred that both seek their prey without depending upon sight. Indeed, in the muddy waters of the rivers they inhabit, eyes can be of little use, and it has been suggested that these fish depend chiefly upon their beak, which is probably employed as an organ of touch. The fiesh of both species is eaten. Among several fossil forms, we may mention the genus Crossopholis, of the North American Eocene, on account of the retention of a series of oblique rows of scales VOL. V.—33 514 GANOIDS. on the upper lobe of the tail, as we thus have evidence of the descent of the family from fully scaled fishes. Toothless From the preceding family the typical sturgeons (A cipenseridw) Sturgeons. may be distinguished by the absence of teeth in the adult, and the presence of five longitudinal rows of bony plates on the naked body, which is elongate and subeylindrical in form, as well as by the presence of four barbels in a transverse line on the under surface of the muzzle. The muzzle is somewhat produced, and either subspatulate or conical in form, with the small, transverse mouth on its lower surface. All the vertical fins are armed with a single series of fulcra on their front edges; the dorsal and anal are situated at a moderate distance from the caudal; and the large air-bladder is simple. Confined to the temperate regions of the Northern Hemisphere, sturgeons are either exclusively or partially fresh-water fish, some of them only ascending rivers for the purpose of spawning, after which they return to the sea. With the slender-beaked sturgeon, they include the largest fresh-water fishes of this region, several of the species commonly growing to 10 feet, while some are much larger. The females deposit enormous numbers of extremely minute eggs, the product of a single individual having been estimated at upwards of three millions during a season. This wonderful fecundity easily accounts for the enormous numbers in which sturgeon, in spite of constant persecution, still crowd the northern rivers during the spawning-season. In addition to the excellence of their flesh, sturgeon are valued for their roe, from which is manufactured caviare, and for their air-bladder, the inner coat of which forms the basis of isinglass. In a fossil state sturgeons are unknown before the upper part of the Eocene period. All the members of the genus are exceedingly voracious fishes, and the majority are mainly carnivorous. During the winter many or all of them crowd together, either in inlets of the sea, estuaries, or the deep pools of rivers, where they undergo a kind of hibernation; and it is stated that in some localities they bury their noses in the mud, with their bodies and tails standing vertically upwards like a series of posts. They mcrease very rapidly in size; and the eggs are hatched in five days. Although still abundant in the northern rivers, in those of Central Europe sturgeon have greatly decreased in numbers, and few really big fish are now taken. In the beginning of the year, when they are still torpid, sturgeon are captured by breaking the ice, and stirring up the mud at the bottom of their haunts with very long poles armed with barbed prongs. As the fish seek to escape, some are stabbed with the spears; and it is said that half a score of large fish may be thus taken by a single fisherman. In summer regular fishing-stations are established on the Russian rivers, where the approach of a shoal is heralded by a watchman. Upwards of fifteen thousand sturgeon have been taken in a day at one of these stations; and when the fishing is suspended for a short time, a river of nearly four hundred feet in width, and five-and-twenty in depth has been known to be completely blocked by a solid mass of fish. The common sturgeon (Acipenser sturio), of which a small example is shown in the illustration facing p. 510, is the typical representative of the first genus, in which the rows of bony plates remain distinct from one another on the tail, spiracles are present on the head, the upper lobe of True Sturgeons. STURGEON TRIBE. 515 the tail is completely surrounded by the fin-rays, and the muzzle is either short or developed into a narrow beak of moderate length. There is some doubt as to the exact number of species of sturgeons, as these fish vary considerably according to their age, but it is probable that nearly twenty different kinds may be admitted. Among the better known forms one of the most esteemed is the sterlet (A. ruthvenus), which although rarely exceeding a yard in length, yields better flavoured flesh and tiner caviare than any of the others. It is characterised by its narrow, pointed snout, and by the great number of bony plates on the sides of the body; these varying from sixty to seventy. Common in the Black Sea and Caspian, as well as in their influent rivers, the sterlet is likewise found in the Siberian rivers, while it STERLET (;'; nat. size). ascends the Danube as far as Vienna. In contrast to this species, may be noticed the giant sturgeon, or hausen (S. iuso), shown in our full-page illustration. Having from forty to forty-five lateral bony plates, this species may be readily distinguished by the absence of shields on the muzzle, which is rather short and pointed. It is found in the Black Sea, Caspian, Sea of Azoy, and their tributaries, and occasionally enters the Mediterranean. At one time this sturgeon was to be met with in the Danube by thousands, among which specimens of upwards of 24. feet in length were by no means uncommon; but relentless slaughter has greatly reduced not only their numbers but likewise their size, although even now fish of from 1200 to 1500 Ibs. weight are occasionally taken. These, however, are mere pigmies to certain Russian examples, one of which is stated to have weighed 516 GANOIDS. 2760, and a second 3200 lbs. Migratory in its habits, this sturgeon crowds into the Russian rivers as the ice is breaking up, when many individuals are more or less severely injured by being jammed against the floes. It appears that only full- grown fish ascend some rivers, as no small ones are found in the Danube; but in the Volga these sturgeon are stated to remain during the winter in a semi-torpid condition. Although extremely powerful, the hausen is an inactive and timid fish, fleeing even from the diminutive sterlet, and passing much of its time on the mud at the river-bottom, but rising occasionally to swim near the surface. In diet it is both carnivorous and herbivorous, feeding on vegetable substances, other fish, especially various kind of carp, and even water-fowl. Its isinglass is inferior to that of the common sturgeon. Rarely visiting the British coasts, where it is a “royal” fish, the latter species has only from twenty-six to thirty-one lateral plates, and from eleven to thirteen down the middle of the back; the muzzle peing pointed, and about equal to one-half the length of the head. It is a widely distributed form, frequenting the coasts of both sides of the Atlantic, but absent from the Caspian, although found in the Black Sea. In Italy it ascends the rivers from March to May; and while in that country it does not commonly exceed 5 or 6 feet in length, specimens of upwards of 18 feet are on record. Shovel-Beaked The four species of the genus Scaphirhynchus (which must not Sturgeons. be confused with the toothless sturgeons) differ from the preceding genus by the production of the muzzle into a spatulate beak, by the narrow and depressed hinder portion of the tail being completely covered by the bony plates, as well as in the absence of spiracles, and by the fin-rays not surrounding the extremity of the upper lobe of the tail, which terminates in a long filament. Of the four species, one is restricted to the Mississippi river-system, while the others inhabit the rivers of Central Asia; all being exclusively fluviatile in their habits. Allied Extinct The genera Chondrosteus and Belonorhynchus from the European Families. Tias severally represent two families differing from all the modern sturgeons in the absence of a median unpaired series of bones in the head-shield, and also in the possession of branchiostegal rays. In the latter family the tail is diphycereal, and there are longitudinal series of bony plates on the body; whereas in the former the tail is heter- ocercal, and the body is either naked or with a small series of scales on the upper lobe of the tail; both being furnished with teeth. The — sealed types of this sub- order are so utterly unlike the sturgeons in external appear- ance that it is only by a study of their internal structure that their true affinities have been Scaled Types. AN EXTINCT ACIPENSEROID FISH (Platysomus), from the determined. They RAS all Magnesian Limestone. extinct, and mainly character- FRINGE-FINNED GROUP. ity) istic of the Secondary period, their remains being especially common in the British Lias. In both of the two principal families the tail is of the heterocereal type. In one family, as typified by the genus Palwoniscus, the body is elongated fusiform, and the teeth are slender and conical or straight. On the other hand, Platysomus represents a second family (Platysomatide), in which the body is rhomboidal, and the teeth—in the upper jaw mainly confined to the pterygoid bones—obtuse. In both groups the scales are of the ganoid type. THE FRINGE-FINNED GANorDS,—Order CROSSOPTERYGII. The whole of the members of the subclass under consideration described in the foregoing pages constitute one great order (Actinopterygii), characterised, as mentioned on p. 334, by the fan-like structure of the paired fins, and frequently also of the caudal fin; the scales being generally of the cycloid or ctenoid type. These fishes form, indeed, the dominant group at the present day ; whereas the group now to be considered is represented only by two existing species—referable to as many genera, and is mainly characteristic of the earlier epochs of the earth’s = gp a THE BICHIR. history, being abundant even in the Devonian and Carboniferous epochs, since which time it has been steadily decreasing in numbers. These fringe-finned ganoids, as they may be called, have the paired fins lobate, with an internal longitudinal axis belonging to the true skeleton more or less fringed with dermal rays, the caudal fin being either of the diphycereal or heterocercal type. A pair of large jugular plates, bounded in some instances by a series of smaller lateral ones, and an anterior unpaired element, are developed in the branchiostegal membrane to fill up the space between the two branches of the lower jaw, and thus re epresenting the branchiostegal rays of the first order. In all the scales are coated with ganoine, although they may be thin, overlapping, and rounded, or thick and quadrangular. The existing forms have the optic nerves simply crossing one another, a spiral valve in the intestine, and a duct to the air-bladder ; the presence of the latter being also shown in certain extinct types. Next to the sharks and rays, this group is one of the oldest, being well represented in the Devonian. The sole existing survivors of this great group of fishes are the bichir (Polypterus bichir) of the Nile, and other rivers of Tropical Africa, and the reed-fish (Calamoichthys calabaricus) from Old Calabar; these constituting the family Polypteridw, which has no fossil representatives, and probably forms a subordinal group by itself. In this family the notochord is more or less constricted and replaced by ossified vertebrae; the baseosts, or superior supporting elements, are rudimentary, or wanting, in the median fins; whereas the Existing Species. 518 FRINGE-FINNED GAWNOJDS. axonosts, or inferior supports, form a regular series equal in number to the dermal fin-rays with which they articulate. The scales are ganoid, and the fins without fulera. The dorsal fin is divided into a number of finlets, each formed by a spine in front and a series of rays behind; the anal fin being situated close to the diphycereal caudal, and the vent near the end of the tail, while the whole caudal region is very short. In the bichir the body is moderately elongated ; the teeth are rasp-like, and arranged in broad bands in the jaws and on the vomers and palatines, the jaws also bearing an outer series of larger pointed teeth; and the pelvic fins are well developed, but do not show the obtusely lobate structure characterising the front pair. The large air-bladder is double. The bichir is found in the Upper Nile and the rivers on the west coast of Tropical Africa, examples being occasionally carried down into the Lower Nile. The number of finlets varies from eight to eighteen, and in size this fish grows to as much as 4 feet. Nothing is known of its habits. The reed-fish is a smaller form, charac- terised by the great elongation of the body, and the absence of pelvic fins. Very little can be said here as to the numerous extinct repre- sentatives of this group. One subordinal group (Actinistia) is represented by the hollow-spined ganoids (Celacanthidw), which range from the Extinct Families. ttt, y (Sh Ae SHA Ly ALLL Kee Y WWMM EIEE ¢ RIN AAA AA ELA * ‘ avai AAAE SASSER CEE CCT ‘ CQ - SOS SAAN OND tp pS lLITID SKELETON OF A HOLLOW-SPINED FRINGE-FINNED GANOID, Undina. (From A. 8. Woodward, Cat. Foss. Fish, Brit. Mus.) Carboniferous to the Jurassic, and are best known by the genera Celacanthus and Undina. In these fishes (as shown in the accompanying figure) the notochord persists ; the axonosts of the anal and two dorsal fins are fused into a single piece ; in the caudal fin the dermal fin-rays are each supported by a series of axonosts, equal in number to the upper and lower spines of the vertebrxe; and each pelvic has a single axonost, which is not united with that of the opposite side. In these fishes the body is deeply and irregularly fusiform, with the scales overlapping, rounded, and more or less coated with ganoine. There is a gill-cover and a single pair of jugular plates; the paired fins are obtusely lobate; the tail is diphycereal, frequently with a small supplemental fin at the extremity; and the air-bladder is ossified. ~—--- more or less mark- edly triangular spines inserted in the skin by their bases. In some cases the teeth con- sisted of a single cone, with one small basal cusp; but in other forms they seem to have coalesced into a pavement-like structure. No traces of calcification have been detected in the notochord. As might have been expected, these primitive sharks were of comparatively small size, averaging from 3 to 4 feet in length. RESTORATION OF A FOLD-FINNED SHARK (Cladoselache).—After Dean. THE EXTINCT SPINE-FINNED SHARKS,—Order ACANTHODII. Whereas the two preceding groups contain the most primitive and generalised representatives of the subclass, the order now to be considered, which is likewise confined to the Paleozoic epoch, comprises sharks of a more specialised type than any existing forms. Indeed, these spine-finned sharks bear much the same relationship to the lobe-finned group, as is presented by the bony fishes to the fringe-finned ganoids; and in a strictly natural arrangement these forms should stand at the head of the class, although it is more convenient to con- sider them in this place. One of the essential features of the group is to be found in the development of mem- brane-bones overlying the original cartilagin- ous skull; the socket of the eye being also frequently surrounded with a ring of bones of similar origin. In the internal skeleton the notochord is persistent, and the cartilages are superticially calcified, frequently with a granular structure. When teeth are present, these are firmly fixed upon membrane-bones overlying the cartilages corre- sponding to the functional jaws of other sharks. The gill-arches bear a series of RESTORATION OF A SPINE-FINNED SHARK (Acanthodes). (From A. 8S. Woodward, Cat. Foss. Fish. Brit. Mus.) 548 SHARKS AND RAYS. appendages which during life were probably furnished with membranous expan- sions similar to those of the existing frill-gilled shark. In the fins the cartilages of the internal skeleton are greatly reduced, and the membranous portions are almost destitute of cartilaginous rays; while each of the paired and most of the median fins are provided with a large spine on the front edge. The tail is of the heterocercal type, and the males lack the claspers characterising the existing forms. Externally the body is covered with small and closely-arranged quad- rangular granules, between two series of which runs the lateral line. Three families constitute the order; the first of these, as represented by the genus Acanthodes, having but a single dorsal fin; while in the other two—respectively typified by Ischnacanthus and Diplacanthus—there are two of these fins. THE LOWEST VERTEBRATES AND ER ATES ees CHA Pm ae THE LAMPREY Group,—Class Cyclostomata. TILL within recent years both the lampreys and the strange little creature known as the lancelet were generally included among the class of fishes, which was also taken to comprise a number of armoured extinct forms, of which a brief notice is given below. On the other hand, the marine animals commonly termed sea-squirts, but technically known as ascidians, together with certain aberrant worm-like creatures, were classed with the great assemblage of so-called Invertebrates. Anatomical and paleontological investigations have, however, revolutionised our ideas concern- ing the creatures in question, with the result that while the lampreys are now separated from the fishes to form a class by themselves in the vertebrate subking- dom, the lancelet and sea-squirts, together with the above-mentioned worm-like creatures are now regarded as forming a subkingdom by themselves, known as the Semivertebrates, or Protochordata. The reason for the separation of the lampreys from the fishes will be gathered when we come to that group; but we must briefly notice in this place the considerations which have induced naturalists to brigade in one group such very dissimilar creatures as the lancelet, sea-squirts, and the afore- said worms. In the introduction to the Vertebrates given in the first volume we have indicated the leading structural features of that group—more especially as developed in its higher members; among these one of the most important being the dorsal position of the great nervous system, or spinal marrow, which in the higher forms is under- lain by the bodies of the vertebrae. In our description of the fishes we have, how- ever, seen that in some of the lower forms the vertebrae are represented only by the original cartilaginous rod known as the notochord, from: which they are developed by constriction in the higher types. To this we have to add that in the earlier stages of their development all vertebrates possess gill-slits, which persist in their original condition only in the fishes and lampreys. Now the result of anatomical investigations has been to show that the lancelet, sea-squirts, and the aforesaid worm- like creatures agree with the Vertebrates in the possession of a dorsally-situated nervous system, of a notochord, and of gill-slits; and thereby differ from all 550 LOWEST VERTEBRATES. other known animals. Consequently we may classify the animal kingdom as follows :— I. CHORDATE ANIMALS— Division CHORDATA eee ARR 1. Vertebrates—Subkingdom VERTEBRATA. (1) Mammals—Class MAMMALIA. (2) Birds—Class AVEs. (3) Reptiles—Class REPTILIA. (4) Frogs and Salamanders—Class AMPHIBIA. (5) Fishes—Class Pisces. (6) Lampreys and Hag-Fishes—Class CyCcLOSTOMATA. 2. Semivertebrates—Subkingdom PRoTrocHoRDATA. (1) Lancelets—Class LEPprocarptm. (2) Sea-Squirts—Class TUNICATA. (3) Worm-Like Forms—Class ENTEROPNEUSTA. II. Non-CHorpDaTE ANIMALS—Division INVERTEBRATA { Nervous System Ventral; no Notochord or Gill-Slits. We shall consider briefly the suggestions that have been made concerning the relationships between the semichordates and nonchordates at the close of this volume, and therefore proceed at once to the lampreys. Before doing so it may, however, be as well to mention that to rightly understand the peculiarities of all these matters requires a considerable amount of anatomical knowledge on the part of the reader; and structural features will accordingly be alluded to as simply and shortly as possible. THE LAMPREYS AND HAG-FISHES,—Subclass Marsipobranchii. As a class, the lampreys and their near allies the hag-fishes, with which may probably be grouped certain armoured extinct forms, are distinguished not only from the fishes, but likewise from all the vertebrates hitherto described, by the absence of true jaws, by the single aperture of the nostrils, as well as by the rasp- ing tongue; there being no limbs or ribs, and the notochord either persisting in its original form or being merely surrounded by a series of calcified rings. Probably many or all of these characters are applicable to certain extinct forms now con- sidered as more or less nearly allied to the lampreys, and we may accordingly provisionally regard these as distinctive of the subclass. On the other hand, we may consider the under-mentioned features distinctive of the lampreys as the represen- tatives of a subclass (Marsipobranchii), apart from the aforesaid extinct forms. In the existing members of the group the skeleton is cartilaginous; the skull, as in the chimeeroid fishes and some of the sharks, is immovably joined to the vertebral column; and the gills are in the form of fixed pouches (hence the name of the sub- class), without gill-arches, and either six or seven in number, with their external apertures usually opening on the sides of the neck. Anterior in position, and adapted for sucking, the mouth is surrounded by a circular or subcireular lip supported by cartilages. The naked body is provided with median fins, having cartilaginous rays like those of many fishes. Internally, the heart is devoid of the anterior expansion known as the bulbus arteriosus; the intestinal canal is LAMPREYS AND HAG-FISHES. 551 straight and simple; and the reproductive organs discharge into the cavity of the body. The place of teeth is taken in some forms by horny structures, while in others the mouth is completely unarmed. Some difference of opimion exists among naturalists as to whether the absence of the true jaws in the lampreys is an original or an acquired feature; but, to our mind, the apparent want of these organs in the primitive extinct lampreys seems to be strongly in favour of the former view. The true lampreys, of which the sea- lamprey (Petromyzum marinus), viver-lamprey (P. fluviatilis), and the small lamprey (P.branchialis) occur in Britain, are the typical representatives of a family True Lampreys. SEA-LAMPREY, RIVER-LAMPREY, AND SMALL LAMPREY (} nat. size). (Petromyzidw) characterised by the nasal duct terminating in a closed sac behind, without perforating the palate. As in all the other members of the grou fan) fo} ? the naked body is eel-like in form; but the family is peculiar in that its members undergo a metamorphosis, the young being devoid of teeth, and furnished with a single median fin, whereas in the adult the sucking-mouth is furnished with horny teeth resting on a soft cushion, and the median fin is divided. In the adult the tongue is furnished with rasping teeth, while above and below the aperture of the mouth there are a series of upper and lower teeth, and the sucking-disc is likewise provided with smaller isolated teeth. Eyes are present in the adult; and the aperture of the nostrils is situated in the middle of the head. The seven-gill pouches open externally by as many apertures on each side of the neck, but com- 552 LOWEST VERTEBRATES. municate with the pharynx by a common opening to which the ducts of all con- verge. The intestine is furnished with a spiral valve, and the eggs are minute. The true lampreys are characterised in the adult condition by having two dorsal fins, the hindmost of which is continuous with the caudal; and likewise by the upper series of oral teeth consisting either of a doubly-cusped transverse ridge, or of two closely-placed separate teeth; while the teeth on the tongue are serrated. The genus appears to be represented by four species, which are confined to the coasts and fresh waters of the Northern Hemisphere, ranging as far south as West Africa. The largest of these 1s the sea-lamprey, represented in the upper figure of our illustration, which may grow to as much as a yard in length, and is common to Europe, North America, and West Africa. On the other hand, the river-lamprey, or lampern, which at certain seasons ascends the rivers of Europe, North America, and Japan in innumerable hosts, is somewhat less than two feet in length, and differs from the last species in being uniformly coloured, instead of marbled with black. Still smaller is the small lamprey, also known as the pride or sand-piper, which is likewise common to Europe and Western North America, and scarcely reaches one foot in length; its coloration being uniform. The young of this form was long regarded as a distinct genus, under the name of Ammocetes; but its true nature was discovered by watching the transformation into the adult. The larva, writes Dr. Giinther, requires three or four years for its full development. At first the head is very small, and the cavity of the mouth “surrounded by a semicircular upper lip, the separate lower lip being very small. There are no teeth, but several fringed barbels surround the mouth. The extremely small eyes are hidden in a shallow grove ; but there is a median single nasal opening, and seven gill-openings, as in the adult. The vertical fins form a continuous fringe, in which the later divisions are more or less distinctly indicated.” When open, the mouth of lampreys is nearly cireular in shape, but when closed forms a narrow shit. Much has still to be learned regarding the habits of lampreys, but it appears that all the members of the present genus ascend rivers for the purpose of spawn- ing, and that some of them pass the whole of their larval conditions in fresh waters. They are all carnivorous, and in the adult state attach themselves by their mouths to the bodies of fishes, from which they rasp off the flesh with their horny teeth ; fish being not unfrequently met with bearing the scars of wounds thus inflicted, and a salmon has been taken high up in the Rhone with a sea-lamprey tightly adhering to its side. Bathers have also been known to be attacked by the same species. Commonly keeping to the bottom, the sea-lamprey may at times be seen swimming near the surface with a serpentine movement of the body. In the Severn the capture of this species lasts from February to May, while in the Thames the season is May and June; but in the Scottish rivers the lampreys do not ascend till the end of June, remaining till the beginning of August. During the spawn- ing-season these fishes excavate furrows in the river-bottoms for the reception of their eggs, and are said to remove impeding stones by hfting them up with their sucking-mouths. Being much exhausted by the function of spawning, at its con- clusion they make their way with all speed to the sea. The river-lamprey was at one time thought to be a permanent inhabitant of fresh waters, but it has been taken in the sea, and it has even been considered that it may undergo its meta- LAMPREYS AND HAG-FISHES. 553 morphosis in salt water. Always restricted to low-lying countries, this lamprey may be found alike in rivers, streams, lakes, and marshes, although it only spawns where the water is clear and flows swiftly over a stony bed. During the spawning- season, which takes place in March and April, the lampreys acquire a brilliant metallic lustre; while at the conclusion of the function they generally perish. Formerly these lampreys occurred in enormous quantities in many of the English rivers, upwards of three thousand having been taken at Newark in a single night; but the numbers in the Thames are now considerably diminished. Their chief use is as bait for cod and other fish; for which they are specially adapted on account of the ease with which they can be kept alive. There is nothing calling for special notice with regard to the habits of the small lamprey. Southern In the Southern Hemisphere the family is represented by three Lampreys. genera, in one of which there is a single species (Mordacia mordax) common to the coasts of Chili and Tasmania; while in a second (Geotria) there is one Chilian and another South Australian species. The first of these two genera agrees with the typical representatives of the family in the continuity between NE HAG-FISH (2 nat. size). the second dorsal and caudal fins, but differs in having two groups of three-cusped teeth above the aperture of the mouth; whereas in the second genus the two fins above-mentioned are separate, and there is a four-lobed plate above the mouth. Some of these lampreys grow to a length of a couple of feet; and in the adults of some or all of them the skin of the throat is so much expanded as to form a kind of pouch. The third genus (Hxomegus) appears to be known only by two examples from the Atlantic side of South America, one of which was picked up in the streets of Buenos Aires in 1867, while the second was obtained from the Bay of Monte Video in 1890. With the exception that the dentition is of a peculiar type, very little is known as to the structure of this rare form. It will not fail to be noticed that the remarkable geographical distribution of these southern lampreys is paralleled by that of certain fresh-water fishes already described, with the exception that there is no instance among the latter where a species is common to Australia and South America. The hag-fishes, of which there are two genera, constitute a family (Myxinide) distinguished from the last by the nasal sac having a posterior duct which perforates the palate; the single external nasal Hag-Fishes. 554 LOWEST VERTEBRATES. aperture being situated above the mouth at the extremity of the head, which is furnished with four pairs of barbels. ‘The mouth is devoid of lips, the palate is provided with a single median tooth, and there are two comb-like series of rasping teeth on the tongue. The gill-apertures, or aperture, are situated at a con- siderable distance from the head; and each gill-pouch has a separate duct opening into the cesophagus. The sides of the abdomen carry a row of mucous sacs, and there is no spiral valve to the intestine. The large eggs are invested in a horny envelope, furnished with threads for adhesion. In the true hag-fishes, of which the common species (Myxine glutinosa) is found on the coasts of Europe and North America, there is but a single gill-opening on each side of the abdomen, leading by means of six ducts to as many gill-pouches. Another species has been recorded from the extremity of South America; and the range of the genus also includes Japan. In the second genus (Bdellostoma), of which there are two species from the coasts of the South Pacific, there are six or more gill-openings on each side, each communicating by a separate duct with a gill-chamber. All these creatures are marine, and are frequently found deeply buried in the bodies of fishes, more especially members of the cod family, into which they bore for the purpose of feeding on the flesh. They are totally blind, and secrete vast quantities of slime, which seriously inter- feres with fishing in localities where these creatures abound. Met with in the fjords of Norway at a depth of about 70 fathoms, hag-fishes have been dredged from depths of nearly 350 fathoms. Primeval The Old Red Sandstone of Caithness Lampreys. has yielded the skeletons of a small limb- less creature (Palcwospondylus), which there is little doubt must be regarded as one of the forerunners of the modern lampreys. Measuring only about a couple of inches in length, these skeletons show a well-calcified skull, while the notochord is surrounded by a series of calcified rings, and the tail has a large fin, of which the supports on the upper side are forked like those of lampreys. The front of the head has a circular opening SLIGHTLY ENLARGED REsToRaTIon SULrounded with a ring of tentacles (de, lc), probably OF THE SKELETON OF THE corresponding to.the mose of a modern lamprey .wrle PRIMEVAL LAMPREY. — After . . . awe opening of the nose itself (7) appears to be single; and there are a pair of plates (#) behind the head not improbably representing gill-plates. It may be confidently assumed that this little creature is but one among a series of lost types. CHA PT ik ie THe ARMOURED PRIMEVAL VERTEBRATES,—Subclass OsTRACOPHORI. A Group of remarkable armoured forms from the Paleozoic rocks formerly placed among the fishes, are now regarded as probably constituting a subclass of the class typically represented by the lampreys, although it must be confessed that we have at present no evidence of the links which, on this view, must be supposed to have connected the two groups. Strange in form, and utterly unlike any living animals, these primeval armoured vertebrates are characterised by the ereat development of the external skeleton, the head and fore-part of the body being protected by large bone-like plates. There are no hard structures to the mouth, and there are, at most, but rudimental indications of arches for the support of limbs, while the notochord is persistent. They may be divided into three chief groups; and one of the most curious features connected with the first of these is the apparent structural identity of one layer of its shield with a layer found in the investment of the hving king-crabs. The simplest of these armoured forms is typified by the genus Pteraspis of the Devonian rocks, a partial restoration of which is given in the annexed figure. In these creatures the head and fore-part of the body are protected both above and beneath by shields; while the tail, in some eases at least, is scaled. The structure of the shield is curious, each plate consist- ing of an outer and inner hard layer, between which is a thick stratum of polygonal chambers, perforated by delicate tunnels of the sensory canal-system of the skin; all the layers lacking the ele- ments of true bone, and the outer surface being marked with fine con- Pteraspis. ‘ Penni TT A PARTIAL RESTORATION OF Peraspis. Centric SLL1ez. re eyes (From A. 8. Woodward, Cat. Foss. Fish. Brit. Mus.) are lateral and widely separated, and towards the hinder end of the back shield (which is provided with a spine) there is an aperture on each side for the escape of water from a gill- cavity. Although nothing is known as to the form and structure of the nose and mouth, the nostrils must evidently have been placed near the mouth on the under surface of the head. A pit between the eyes probably marks the site of a rudimental median eye; and the structure of the under surface of the shield indicates the presence of separated gill-pouches, which were probably supported by arches. From an examination of the whole structure of the remains, Mr. A. S. Woodward is of opinion that the shield probably covered “a truly fish-lhke head ; 556 LOWEST VERTEBRA LES: and if it was not for the invariable absence of limbs and jaws, and the forward position of the breathing apparatus in Pferaspis and its allies, these animals might be placed, without hesitation, in the class of fishes. The possibility that limbs and jaws were present, but not calcified enough to be preserved, must, however, be borne in mind; while the negative evidence on this subject, and the want of information as to the nature of the tail, are factors necessitating caution in the determination of affinities.” The next family of the group is typified by the genus Cephalaspis, in which the front shield appears to be confined to the head and gill- region, and consists of a single piece, rounded or pointed in front, abruptly truncated behind, and with the rounded margin bent inwards below to form an ornamented flattened rim. Of the triple-layered shield, the inner layer is bony, the thick middle one solid, although traversed by a network of blood-vessels, while Cephalaspis. the upper one is tuberculated and resembles teeth in structure. The eyes are placed close together in the middle of the shield, the nostrils must have had much the same position as 1m Pteraspis, and at the back of the shield there occurs on each side a small flap which must be regarded as a gill-cover. Immediately behind the shield commences the ordinary scaling of the body, without any signs of arches for the support of limbs. Paired fins appear, RESTORATION OF Cephalaspis. (From Woodward, Cat. Foss. Fish. Brit. Mus.) indeed, to be totally absent, although a dorsal and a caudal fin, stiffened by little elongated scales in place of rays, are present. The large, deep, quadrangular scales covering the body form a series of interlocking rings, doubtless corresponding in the living state to the underlying muscle-plates of the body. The third modification of the group, as represented by the Devonian Pterichthys, agrees in the general structure of the shield with certain members of the last section in which there is no dividing line between the head-shield and the united scales of the body. The head is, however, sharply defined from the body; and the armour, instead of being simple, consists of a number of overlapping plates arranged symmetrically to one another. An Pterichthys. important point of distinction from all the preceding forms is to be ag found in the presence of a pair of hollow limb-like pectoral append- ages, jointed near the middle. A small movable plate between the ‘ eyes seems to have lodged a median = eye; another movable plate on the RESTORATION OF PTERICHTHYS. (From Traquair.) cheek appears to represent the gill- cover; and a pair of loose jaw-plates on the lower surface of the front of the head, in some forms at least, are finely toothed on the hinder border; but nothing definite is known with regard to the nature of the nose, mouth, and jaws. EXTINCT ARMOURED FORMS. sis The arrangement of the median fins is generally similar to that obtaining in the second family. With regard to the true nature of the pectoral appendages. Mr. Woodward writes that they are commonly considered “as homologous with the paired pectoral fins of fishes, and certainly in their mode of fixation to the trunk there is much to favour that supposition; but the discovery of an allied organism in the Devonian of Spitzbergen suggests the wisdom of suspending judgment. The dorsal body-shield of the latter is simpler than that of Pterichthys, but the arrangement of the plates on the ventral aspect is identical, and there are also hollow pectoral appendages. These appendages, however, are merely simple triangular spines, firmly fixed by suture to processes of the body- armour; and if they are an inferior or special condition of the ordinarily movable arms, it seems not unlikely that those arms will prove to be different in origin from the paired limbs of fishes.” GH As? Tap ee Tur LANCELETS,—Subkingdom PROTOCHORDATA. Class Leptocardii. COMMON LANCELET, SINGLY, AND IN A CHAIN ( nat. size). Wirn: the curious semitransparent little creatures known as lancelets, forming the only family (Branchiostomatide) and genus of the class to which they belong, we leave the Vertebrates and come to the lower group of Protochordates; all of which retain the three essential vertebrate features mentioned on p. 549. First described by the German naturalist Pallas in 1778, from a specimen captured on the Cornish coast, the common lancelet (Branchiostoma lanceolatum) was referred to that refuge for the destitute, the Mollusca, where it remained till 1834, when it was rediscovered by Costa, on the Neapolitan coast, who gave the name of Branchiostoma, and placed it among the fishes, in the neighbourhood of the lampreys and hags. It was again discovered by Yarrell in 1836, who assigned the title of Amphioxus, and was the first to recognise the existence of a cartilaginous vertebral column, or notochord. The upper figure of our illustration shows the pointed extremities of the body, and also a number of chevron-shaped lines, with their angles directed forwards, these being the partitions dividing the longitudinal mass of muscle clothing each side of the body into a series of segments. And it is due to this segmented structure that the lancelet is enabled to swim so speedily as it does, its progress being effected by serpentine movements of the body. Paired fins are wanting; but the back is provided with a continuous dorsal fin, expanded posteriorly into a caudal fin, and continued forwards to join the ring of feelers, or LANCELETS. 559 tentacles, growing from the margin of the hood-like expansion of skin which surrounds the mouth. The notochord extends to the anterior and posterior extremities of the body, reaching beyond the muscle-plates, and likewise in advance of the front extremity of the overlying nerve-chord; the latter feature being peculiar to the lancelet. An aperture distant about two-thirds of the whole length from the head, and opening in the middle line of the lower surface of the body, is the outlet of a large cavity, or atrial chamber, surrounding most of the internal organs, and especially the large pharynx; and the vent, as in many tadpoles, is situated high up on the left side, near the hinder end of the body. The reprodue- tive organs, which form oval structures lying below the muscle-plates, differ from those of the Vertebrates in that they consist of a large number of perfectly distinct chambers, corresponding to the muscle-segments of the region of the body along which they extend. In connection with the fins, it should be observed that, except at its two extremities, the dorsal fin is supported by a series of gelatinous rays, each lying in a chamber of its own ; while the ventral portion of the caudal fin has a paired series of similar supports. In young and transparent examples, the pharynx, or that portion of the alimentary tract immediately behind the mouth, is distinctly visible through the walls of the body, and can be seen to be perforated on each side by a very large number of vertical gill-slits, opening into the atrial chamber. In the living creature an almost continuous current of water is drawn, for the purpose of breath- ing and feeding, through the mouth into the pharynx, whence it escapes by means of the gill-slits into the atrial chamber, from which it is discharged through the pore. Unlike even the lowest Vertebrates, lancelets have no cartilaginous skull; the only solid structure in the head taking the form of a ring of cartilage in the hood surround- ing the mouth, which gives off a series of processes for the support of the feelers. Although paired eyes, as well as organs of hearing, are totally wanting in these strange little creatures, a pigment-spot at the front end of the nerve-tube represents a median eye; behind which is a small nasal pit,.communicating in the larva by means of a small pore with the front of the nerve-tube. With regard to the other soft-parts, it will suffice to mention that the anterior extremity of the nerve-tube is not expanded to form a true brain; and that the heart is represented merely by a series of pulsating dilatations of the great blood-vessel; the blood itself being devoid of colour. Lancelets are represented by some eight or nine species, all of which may be included in a single genus; although one from the Bahamas is peculiar on account of the unsymmetrical arrangement of its reproductive organs. Essentially littoral forms, inhabiting shallow water, especially where the bottom is sandy, these creatures have an almost universal distribution on the temperate and_ tropical coasts, although they are often curiously local. The European form has been recorded from Scandinavia, Heligoland, the English Channel, France, the Medi- terranean, and Chesapeake Bay, growing to an unusual size in French waters. Other species occur on the Atlantic and Pacific shores of North and South America, as well as on the coasts of Australia, Japan, Ceylon, and the Fiji Islands. Mr. A. Willey remarks that the lancelet “possesses an extraordinary capacity for burrowing in the sand of the seashore or sea-bottom. If an individual be dropped from the hand on to a mound of wet sand, which has just been dredged out of the 560 SEMIVERTEBRATES. water, it will burrow its way to the lowest depths of the sand-hillock in the twinkling of an eye. Its usual modus vivendi is to bury the whole of its body in the sand, leaving only the mouth with the expanded buccal cirri [tentacles] pro- truding. When obtained in this position ina glass jar, a constant inflowing current of water, in which food-particles are involved, can be observed in the neighbour- hood of the upstanding mouths. The food consists almost entirely of microscopic plants (diatoms, desmids, etc.) and vegetable débris . . . Occasionally it emerges from its favourite position in the sand, and after swimming about for some time it will sink to the bottom, and there recline for a longer or shorter period upon its side on the surface of the sand. When resting on the sand, it is unable to maintain its equilibrium in the same position as an ordinary fish would do, but invariably topples over on its side,—indifterently, the right or left;” this inability to maintain its balance being due to the absence of certain structures of the internal ear, to which this function is assigned in fishes. According to another observer, lancelets oceasionally attach themselves to another by their mouths in a chain-like manner, as represented in our illustration. That lancelets indicate an extremely archaic type, and also that they are more nearly allied to the Vertebrates than to the Invertebrates, may be considered certain; although there is still a difference of opinion whether they should be looked upon as simple or degraded forms. CHAP THR ve THE SeEA-SQuirts oR Ascrprans,—Class Tuniecata. A LEATHERY FIXED SEA-SQUIRT, MJicrocosmus (nat. size). EXTERNALLY, scarcely any creatures are more unlike the lancelet than those fixed marine animals commonly known as sea-squirts, and technically as ascidians, or tunicates. Nevertheless, in the opinion of those best qualified to judge, the relationship is probably closer than that existing between the former animal and the larva of a lamprey, in spite of the much greater external resemblance between the two latter. It is, however, when we dissect a sea-squirt that we meet with structures recalling certain features in the anatomy of the lancelet: while to find evidence of the chordate affinities of the former, we have to go back to its larval condition. In the adult condition, writes Mr. Willey, most of the sea-squirts “are sedentary animals, remaining fixed for their lifetime on one spot, whether attached to rocks, stones, shells, or seaweeds, from which they are incapable of moving. There are, however, several very extraordinary genera of ascidians, which swim or float about perpetually in the open ocean, and have become adapted in the extremest VOL. V.—36 562 SEMIVERTEBRATES. manner to a purely pelagic environment.” As there are both simple and compound fixed ascidians, so there are two similar types among the pelagic forms; but some of the latter are complicated by an alternation of generations, the one generation being a simple form, whereas in the other generation the units are aggregated into chains, as shown in our Plate of the creatures known as salpee. Among the compound fixed types the colonies, as they are termed, consist of a number of individuals produced by budding from a single parent-stock: such colonies frequently attaining very large dimensions, and being remarkable for their brilant coloration, although in other cases they merely form thin incrustations on the surface of various marine objects. Other forms, on the contrary, are merely connected at their bases by a common creeping root-like base, from which new buds are from time to time viven off, the individuals being otherwise free." Lo — A LEATHERY SEA-SQUIRT, WITH ONE SIDE OF THE OUTER TUNIC REMOVED (nat. size). Structure of Externally a simple sea-squirt, like the one (A. microcosms) re- Ascidians. presented in the first illustration, has been aptly compared toa leather bottle with two spouts; these spouts forming funnel-shaped projections, one of which—generally situated at a higher level than the other—takes in water, which is discharged from the second. The whole organism is invested in an external tunic, varying much in structure, but being frequently warty, and generally opaque, although in the salpz it is transparent. A remarkable feature connected with this outer tunic is that it contains a substance—cellulose—identical in composition with that forming the cell-walls of plant-tissues. On cutting through the outer tunic, we come, as in our second illustration, to an underlying muscular tunic, forming the true body-wall, and consisting externally of an epidermis underlain by interlacing muscular fibres. In the illustration, @ indicates the inhalent, and b the exhalent orifice of this inner tunic. On cutting into the inner tunic, we find a large so-called atrial cavity, enclosing to a great extent the viscera, and com- municating with the exterior by means of the exhalent orifice. The inhalent orifice, or mouth, communicates, on the other hand, directly with the exceedingly 1 Strictly speaking, the term “individual” includes all the units produced by budding from a common stock, but it is more convenient to use it in the ordinary sense. SLA SOUOLRTS. 563 o large pharynx or branchial chamber, which extends nearly to the hinder end of the body, and is perforated by a vast number of gill-openings, through which the water taken in at the mouth passes into the atrial chamber, Instead of passing directly into the latter chamber with the water, the food is caught up in a mass of slime, and carried round the base of the mouth-tube until it reaches the entrance to the cesophagus, which les near the hinder end of the dorsal surface of the branchial chamber. Hence it passes into the stomach, and along the intestine, which forms a U-shaped curve turned away from the dorsal aspect; the vent opening on the same aspect into the atrial cavity below the exhalent orifice. With regard to the nervous and circulatory system, it will suffice to say that there is a large nerve-ganglion embedded in the tissue of the inner tunic, and lying on the dorsal surface of the body between the inhalent and exhalent orifices; and true blood-vessels are wanting, the blood merely flowing through a series of spaces in the muscles and other tissues of the body and between the viscera, and the heart forming a dilated tube. Unlike the higher Chordates, all the ascidians are hermaphrodite; the reproductive organs frequently lying within the loop of the intestine, and discharging into the atrial cavity alongside of the vent. A remark- able physiological feature of the group is to be found in the periodical reversal of the action of the heart; the blood being driven for a certain time in one direction, after which the heart makes a short pause, and then propels it in an opposite course. In addition to certain other structural features, into the consideration of which it would be impossible to enter in a work of the present nature, the essential resemblance between the adult sea-squirts and the lancelets is to be found in the possession by both of a pharynx perforated by a large number of gill-openings, which convert it into a branchial chamber, opening into an atrial cavity instead of directly to the exterior. Several of the differences between the two, such as the hermaphrodite reproduction and the bent intestine of the sea-squirts, are probably due to their sessile habits, since such features are characteristic of most fixed organisms. Other points of difference are to be found in the absence of segmentation, and the want of a dorsal nerve-tube and notochord in the adult ascidian, although, as we shall see, a remnant of the latter exists in the tail during the larval condition. All ascidians, whether fixed or free in the adult condition, go through a free-swimming larval stage, during a part of which they develop a tail containing a notochord and nerve-tube; and as this feature is all important from a morphological point of view, it must be mentioned here, although necessarily in a very brief manner. Generally the larval condition lasts but a short time; and this may be the reason for the development of the tail, as a powerful swimming organ would seem to be essential in order to enable the Development. creature to reach a spot suitable for its permanent existence. During its develop- ment a groove makes its appearance on one surface of the ascidian embryo, the large cells on the side of which grow inwards so as to enclose a tube, corresponding to the nerve-tube of Vertebrates, beneath which is the notochord. When of an oval shape, and while still contained in its investing membrane, the embryo assumes a ventral curvature, and at the same time produces a long tapering tail, which eventually becomes coiled round it. In addition to certain other structures, this 564 SEMIVERTEBRATES. outgrowing tail includes the nerve-tube and the notochord; and in some forms contains the only muscles developed at all. Subsequently a rudimentary brain, corresponding to a simple structure in the lancelet, makes its appearance; and likewise an unpaired eye, agreeing precisely in structure and mode of develop- ment with the rudimental median eye of the tuatera. After certain other changes, among which the development of a stomach and intestine are included, the larva is ready to burst from its membranes, which it does by spasmodie AU TET Hid | NAVI } UVLO ASLO A | | i ANAT ANT A CARTILAGINOUS FIXED SEA-SQUIRT, Phadlusia (nat. size). jerkings of the tail; and it thereupon starts on a free-swimming existence. Before long the cellular structure of the notochord in the tail begins to disappear by the formation of vacuities; and eventually the whole structure becomes filled with gelatinous matter. After a brief free existence it fixes itself by its muzzle to some submarine object, with the tail stretched out and generally motionless. In a short time this appendage commences to shorten, and finally disappears, by being drawn up into the body of the developing sea-squirt and absorbed. A further process of development results in the production of the perfect sea-squirt; but it SHA-SQUIRTS. 565 would be quite foreign to the scope of this work to enter into the details of the metamorphosis ; and we may conclude this portion of our subject by stating that ascidians are probably the degenerate descendants of permanently free-swimming forms provided with a complete notochord and nerve-tube ; both of which structures are now in most cases only temporarily retained in the tails of the larve. Typical According to the classification adopted by Professor Herdman, Ascidians. the tunicates may be divided into three orders, the first of which is known as the Ascidiacea. This group includes both fixed and pelagic, simple and compound types, none of which are provided in the adult state with a tail and retain no trace of a notochord; the free-swimming forms constituting colonies, and the simple types being generally fixed. The outer tunic is permanent and well developed, generally increasing with the age of the individual; and the muscular structure of the inner tunic takes the form of an irregular network, and never of hoop-like bands. The walls of the large branchial chamber are perforated by numerous slits, opening into a single atrial cavity, which in turn communicates with the exterior by means of the exhalent aperture of the tunic; the vent opening into the atrial cavity. Many of the forms reproduce their kind by budding, and in most the sexually produced embryo develops into a tailed larva. The order is divided into three subordinal groups, of which the first—Ascidiz Simplices— includes fixed (rarely unattached, but never free-swimming) and generally solitary forms, which very rarely reproduce by budding. When colonies occur, each of their individual members has a distinct outer tunic of its own, the whole society never being buried in a common investing mass. Four families are contained in this suborder, each represented by a large number of genera. Omitting mention of the first family, we may take as an example of the second (Cynthiide) the genus Microcosmus, of which specimens are shown in the figures on pp. 561, 562. As a family, these sea-squirts are characterised by being usually attached, and sometimes stalked, although rarely free. The outer tunic is generally membranous or leathery, but occasionally cartilaginous or covered with sand; while the inhalent aperture is usually, and the exhalent aperture invariably, provided with four lobes, meeting together at the centre. The branchial chamber is longitudinally folded, with its gill-slits straight; and the tentacles may be either single or compound. In the figured genus the body is attached and sessile, and the tunic, which is not incrusted with a continuous coat of sand, is thin, leathery, and tough; both its apertures having four lobes, and the tentacles being compound. As an example of the family Ascidiidw we may take the well-known Phallusia manmillata, from the seas of North-Western Europe and the Mediterranean, which is shown in the accompanying illustration, and is the sole representative of its genus. In the family to which it belongs, the body is attached and usually sessile, although rarely stalked; the inhalent aperture generally has eight, and the exhalent six lobes; and, as a rule, the outer tunic is either gelatinous or cartilaginous, although it may be horny. The branchial chamber is devoid of folds, with the gill-shts either straight or curved; and the tentacles are simple and thread-lke. In the figured genus the body is erect and attached, and the outer tunic of a cartilaginous nature; its surface being mammillated in a very characteristic manner. It may be mentioned here that all the simple sea-squirts of this group, when touched, emit 506 SEMIVERTHBRATES. a jet of water; and that some of them, like the one figured on p. 561, are used as articles of food. To the same subfamily as Phallusia also belongs the extensive genus Ascidia, in which the outer tunic is soft and flexible, instead of being cartilaginous. A totally distinct subfamily is, however, indicated by the remark- able deep-sea genus Hypobythius, of which the two known species were obtained at depths varying from six hundred to two thousand nine hundred fathoms, during the voyage of the Challenger. Here we find the cup-shaped or pear-like —" PEAR-SHAPED ASCIDIAN, Lypobythius (75 nat. size). body attached by a longer or shorter stem; while the apertures are circular and not closed by lobes. The outer tunic is cartilaginous, but soft and thin, although thickened in places to form plates. The internal longitudinal bars usually found in the branchial chamber are wanting in this genus; the gill-slits are small and irregularly placed; and the viscera form a compact irregular mass on the dorsal side of this chamber. In the species here figured (H. calycodes), which is from the North Pacific, the stem is of great length, and the outer tunic thickened so as to form a number of nodules or plates; but in the South Atlantic form (H. SEHA-SQUIRTS. 567 moseleyv) the stem is much shorter, and there is only a single plate, situated on the dorsal side. Of very large dimensions, these deep-sea ascidians are decidedly the most beautiful members of the class, and present some resemblance to the glass-sponges. A totally different type of structure is presented by the last family (Clavelinide) of the suborder, in which the body of each individual is attached by its posterior end, and usually by means of a stalk, to a creeping basal stolon, or common mass, from which young individuals are produced by budding. The outer tunic, which is usually thin and transparent, is in most eases gelatinous, although occasionally cartilaginous; and its circular apertures are but seldom distinctly lobed. Folds are wanting in the branchial chamber, but longitudinal bars may be present, although these lack the papille found in the preceding family; and the gill-shts are straight. The tentacles resemble those of the last family in their simple, thread-like form; but the digestive tract is usually extended behind the branchial chamber to form an abdomen. In addition to the ordinary sexual reproduction, colonies may be formed by budding from the common stolon. Ten genera are included in the family, from among which the typical Clavelina is selected for illustration. Here the body is elongated and club-shaped, but with no peduncle beyond the abdomen, and is attached to a delicate, branched, creeping stolon, from which arise the buds. The thin outer tunic is gelatinous or cartilaginous, with its circular apertures devoid of lobes. The inner tunic is likewise thin, with its muscles mainly longitudinal; and the intestinal tract is extended to form a well-marked abdomen. In its restricted sense, the genus includes only half a dozen small species from North-Western Europe and the Mediterranean; the one here figured (C. lepadiforiiis) being characterised by the yellow or brown lines on the region known as the thorax. The second suborder of the typical sea-squirts— Ascidize Compositze—includes fixed forms which repro- duce by buds so as to constitute colonies in which the individuals are buried in a common investing mass, and thus possess no separate tunics. The group includes seven families; and Professor Herdman remarks that A CREEPING ASCIDIAN, Clavelina (nat. size). as many of these have originated independently from simple forms, the whole assemblage is to a certain extent an artificial one. In the first family (Botryllide) the colonies, as shown in the illustration on p. 568, usually form thin inerusta- tions on seaweeds or stones, although they occasionally take the shape of thick fleshy masses ; the individuals being arranged so as to form either circles or ellipses, or in branching lines. The common apertures of discharge are distinct, and usually furnished with lobes; the individual units are short, and show no division of the body into regions; and the outer tunic, which is usually soft, is traversed by numerous vessels with large terminal knobs. Internal longitudinal bars are present in the large and well-developed branchial chamber, in which the gill-shits are numerous; and the simple tentacles do not exceed sixteen in number. Budding may take place either from the sides of the units constituting the colony or from 568 SEMIVERTEBRATES. the vessels in the tunic. Among the five genera constituting the family, the typical Botryllus (figured on p. 572) has the colony thin and incrusting, with the individuals arranged in a circular manner, whereas in Botrylloides they form ellipses or branching lines. In the figured species of the latter (B. albicans), from North- Western Europe and the Mediterranean, the colony is pure white in colour, but in some it is purple with yellow or green markings, and in others yellowish green. As an example of forms in which the colony is thick and massive, we may cite the genus Polycyclus. Passing over the second family of the suborder, we come to the third (Polyclinide), 11 which the colony is usually massive, being sometimes incrusting, but in other cases lobed, or even stalked. The arrangement of the individuals is highly variable; and the common apertures of discharge are usually inconspicuous. Although of an elongated form, the individuals usually differ from those of the family last noticed by being divided into three regions ; the inhalent aperture having six or eight lobes, while the exhalent is frequently provided with a tongue-like process. The gelatinous or cartilaginous outer tunic is frequently stiffened by embedded grains of sand; and the branchial chamber is usually small and poorly developed, with minute gill-slits and no internal longitudinal bars. The | eanihe) on eX tentacles are small and not numerous; the digestive tract potrylloides) ON A SEA- 5 WEED (nat. size). is extended posteriorly to a considerable distance beyond the extremity of the branchial chamber ; and budding takes place from the end of the postabdominal region. The family is represented by well nigh a score of genera, among which Amaruciwi may be selected as an example, on account of its numerous species. Here the colony is massive, being sometimes lobed or stalked; the mode of arrange- ment is usually compound and irregular ; and the individuals are elongated, with six lobes to the inhalent orifice, and the postabdominal region elongated. The species here figured (A. densun) is from North-Western Europe, and is character- ised by its greyish yellow colour, and the abundance of sand in the tunic; but other kinds may be black, orange, or rosy red, or white. In our figure, @ shows A COMPOUND ASCIDIAN (Amarucium) IN WINTER CONDITION (nat. size). fully active individuals; while those in the outer ring indicated by b assume a kind of torpid condition during the winter, but give rise to fresh buds in the spring. Omitting mention of the remaining families of the group just considered, we come to the third and last suborder of the typical ascidians, namely, the phos- SEA-SQUIRTS. 569 phorescent ascidians——A. Lucie. These are represented solely by the genus Pyrosoma, which is thus the only member of the family Pyrosomatide. These ascidians are free-swimming pelagic forms, reproducing by buds in such a manner as to form colonies in the shape of a sac; such colonies sometimes attaining huge dimensions. In the sack thus formed the constituent individuals are embedded in such a manner that all their inhalent apertures open on its outer surface, while their exhalent orifices are situated within the cylinder; the mouth of the sac forming the common discharging aperture. The apertures of the units are not lobed; and the outer tunic is gelatinous and transparent, containing no hard spicules, but provided with numerous minute cells. The branchial chamber is well-developed, and the tentacles are simple. The first four individuals of the colony grow in the form of buds from a rudimentary sexually-developed larva; the subsequent increase taking place by budding from a ventral posterior stolon. The genus is represented only by four species, in one of which (P. elegans) the individuals form regular oblique rows in the walls of the sac, while in the other three they are arranged irregularly. The largest of all is P. spinoswm, from the Atlantic,in which the total length of the colony may be upwards of four feet; this species being distinguished by the surface of the sae being provided only with short sharp spines, instead of with large processes of the tunic. It is to these ascidians that the most beautiful phosphorescence of tropical seas is due, each colony, when stimulated by a touch or shake of the water, giving forth a brilliant ball of bluish hght, which lasts for several seconds, as the organism floats along beneath the surface, and then suddenly disappears. A colony is figured on p. 576. Describing the luminosity produced by these ascidians, Bennett states that on one oceasion in the Australian seas, when he reached the deck, he observed a “ broad and extensive sheet of phosphorescence, extending in a direction from east to west, as far as the eye could reach. The luminosity was confined to the range of animals in this shoal, for there was no similar light in any other direction. I immediately cast the towing-net over the stern of the ship, as we approached nearer the luminous streak, to ascertain the cause of this extraordinary and so limited phenomenon. The ship soon cleaved through the brilliant mass, from which, by the disturbance, strong flashes of light were emitted; and the shoal, judging from the time the vessel took in passing through the mass, may have been a mile in breadth. The passage of the vessel through them increased the light around to a far stronger degree, illuminating the ship. On taking in the towing-net, it was found half filled with Pyrosoma, which shone with a pale, greenish hght; and there were also a few shell-fish in the net at the same time. After the mass had been passed through, the light was still seen astern, until it became invisible in the distance.” Frequently the phosphorescence is intermittent, periods of luminosity alternating with intervals of darkness. Moseley writes that during the voyage of the Challenger, “a giant Pyrosoma was caught by us in the deep-sea trawl. It was like a great sac, with its walls of jelly about an inch in thickness. It was 4 feet in length, and 10 inches in diameter. When a Pyrosoma is stimulated by having its surface touched, the phosphorescent light breaks out at first at the point stimulated, and then spreads over the surface of the colony as the stimulus is transmitted to the surrounding animals. I wrote my name with my finger on 570 SEMIVERTEBRATES. the surface of the giant Pyrosoma, as it lay on deck in a tub at night, and my name came out in a few seconds in letters of fire.” Non-Luminous With the exception of the family just mentioned, and also of a Pelagic Ascidians. second one which constitutes the third order, the present ordinal includes the whole of the free-swimming pelagic group—termed the Thaliacea representatives of the class. Either simple or compound in structure, these ascidians lack both a tail and a notochord in the adult, but have a persistent outer tunic, which may be either feebly or fully developed. In the inner tunic the muscles are arranged in the form of more or less nearly complete circular bands, the contraction of which forms the motive agency of the creatures. The branchial chamber has either two large openings, or a number of smaller gill-slits, leading to a single atrial cavity; the latter communicating with the exterior by the exhalent aperture, and the vent opening within it. In all the members of the group an alternation of generations takes place; and this may be further com- plicated by the individuals of a single generation being unlike one another. During one period of existence temporary colonies may be formed, but these never increase by the budding of the constituent units, which eventually separate from one another and disperse. AN INDIVIDUAL OF A CHAIN-SALPA. @, inhalent, aud 0, exhalent, orifice ; d, gill; c, e, viscera; 7, eye(?); g, pedicle of union (nat. size). The well-known salpz form a suborder—Hemimyaria—characterised by the formation of temporary colonies in the sexual generation, and represent a family (Salpide) distinguished by the muscular bands of the inner tunic being incomplete on the lower surface of the body. Pelagic in habit, and transparent in structure, salpee have been not inaptly compared to a barrel with both ends knocked out; and really consist of little more than a huge pharynx, swimming through the water, and taking in large mouthfuls of the same at each contraction of its muscles. Through the hollow, to below the hinder aperture, runs obliquely a rod-like gill (d) from above the mouth, although this is too narrow to interfere with the free flow of the water; while the lower surface of the interior of the creature is furnished with a ciliated slime-secreting band, corresponding to the structure known in other ascidians and the lancelet as the endostyle. It may here be well to mention that in the lancelet the structure in question is an elongated gland situated at the base of the pharynx, and against which the ends of the SEA-SQUIRTS. 571 gill-bars abut. The only part of the salpa that is not transparent is the thick mass of viscera (¢,c) at the hinder end of the body; while the muscular bands, by the contraction of which the water is driven through the barrel, may be compared to the hoops of the latter. Externally the whole animal is invested with a thick, tough, transparent tunic: and in some forms there are two tail-like appendages to the hinder end of the body. Such is the structure of a salpa: but there are two generations in the life of these creatures, namely, the simple form, second in the lower figure of the Plate facing p. 561. It will be observed that in the chain the individuals are attached to one another by their upper and lower surfaces, and thus have these two apertures free; and when taken from the water the whole chain, which is several feet in length, can be easily resolved into its and the chain-like or aggregate form; the first bemg shown in the upper, and the component units. The specimen represented in the annexed figure is one of these detached units from a chain, the projection marked g being for the purpose of attachment to the neighbouring individual. Although extremely interesting and curious, the whole history of the development of salpze is so complicated that it is almost impossible to explain it fully in a popular work. It may be stated, however, that the solitary salpa is born from an egg carried within the body of one unit of the aggregate form, the embryo being nourished by means of a placenta from the blood of the parent. On the other hand, the chain-salpxe are produced asexually by budding from a stolon within the body of the solitary form. In the chain-salpa the eggs arise, however, at an exceedingly early period of its develop- ment, with the curious result that three generations are present at one time in a single individual. Thus a solitary salpa has within it the buds of an aggregate salpa, the units of which may each contain eggs which will ultimately develop into the next solitary form. And, as a matter of fact, in a solitary salpa the germ-cells of the embryo of the next solitary form are actually visible before the development of the stolon which is to give rise to the chain-form. As the stolon forms in the body of the latter, it includes within it the mass of germinal cells; and while the former elongates to form the chain of units, the mass of germ-cells likewise lengthens, with the result that a single egg-cell is shut off in each unit of the chain. Simple salpz vary in size from a quarter of an inch to upwards of eight inches; and in some parts of the ocean-surface are met with in inealeulable swarms. Although more abundant in tropical than in the cooler seas, their northward range extends beyond Scotland and Norway, while to the south they have been taken below the latitude of Cape Horn and the most southern point of Australia. Dr. Brooks writes that “they are abundant only after the water has been for some time undisturbed by winds; and as prolonged calms are most frequent in warm seas, those waters are most favourable for the development of these animals, which multiply with most astonishing rapidity. The smaller species are often so abundant that for hundreds of miles any bucketful of water dipped up at random, will be found to contain hundreds of them. In such places collecting with the surface-net becomes impracticable, for almost as soon as the net is dropped into the water, it becomes choked with a mass so dense that nothing can enter it.” The food of these creatures consists of minute marine organisms, both animal and vegetable. In swimming, chain-salpze progress by an undulating, snake-like move- 572 SEMIVERTEBRATES. ment. Usually, the family is divided into the two genera Salpa and Cyclosalpa, the latter being distinguished by having the digestive tract coiled up; but some writers have divided the first of these two into several subgeneric groups. A second family is represented by the very imperfectly known genus Octacnenvus, dredged at depths of between one and two thousand fathoms in the South Pacitic; the body being much flattened, and probably attached by one extremity. Nothing is known as to the life-history of this singular form. Cyclomyaria—of the free-swimming non-luminous as- The second suborder cidians takes its name from the muscular bands of the inner tunic forming perfect rings, and is typically represented by the genus Doliolum. The life-history is complicated by polymorphism; the tailed larva developing into a sexless form, the buds from which give rise to nutritive units, fostering units, and reproductive units. In the typical genus all the muscles form encircling hoops, and the three forms of the sexual generation occur together on one stolon, or outgrowth ; but in Anchinia there are only two complete muscular rings, and the three forms of the sexual generation are produced successively. The free-swimming form known as Appendicularia is the type of the third and last order—Larvacea—of the class, all the members of which are characterised by the possession in the adult state of large tail-like appendages, furnished with a skeletal axis. These creatures, which are of minute size, have not undergone the degeneration so noticeable in the adult of the other tunicates, and thus correspond much more closely to the larval stage of the latter. A curious feature is the rapid production of a temporary outer tunic, which may be shed at any time, and replaced by a second one. There is no separate atrial cavity; and the branchial chamber is simply an elongated pharynx, with two openings on the lower surface, which correspond to the gill-slits, and are well furnished with cilia. The nervous system consists of a large ganglion placed in the anterior part of the dorsal surface, followed by a long chord, provided with smaller ganglia, and extending backwards over the intestine to reach the tail, where it runs along the left side of the skeletal axis. The intestine itself is situated behind the branchial chamber, and the vent opens on the inferior or ventral aspect of the body in advance of the gill-slits. Neither budding, meta- morphosis, nor alternation of generations takes place; and the reproductive organs are situated at the hinder end of the body. The group comprises only the single family Appendiculariide, which contains five genera, the names and characters of which it will be unnecessary to mention. Tailed Ascidians. Botrylius (nat. size and enlarged). CHAP 2B Re Ne THe Worn-Like ProtocHorDATES,—Class Enteropneusta THE last, and at the same time the lowest, group of the Proto- chordates is typically represented by the marine Balanoglossus. Living buried in the sand or mud of the seashore, these worm-like creatures exhale a peculiar odour resembling that of the chemical substance termed iodoform, and Balanoglossus. secrete a copious supply of slme, to which adhere particles of sand, thus forming a protective tube for their bodies. At the front extremity of the creature, writes Mr. Willey, “there is a long and extremely sensitive proboscis, which is capable of great contraction and extension, and is in the ving animal of a brilliant yellow or orange colour. Behind the proboscis follows a well-marked collar-region, con- sisting externally of a collar-like expansion of the integument, with free anterior and posterior margins overlapping the base of the proboscis in front and the anterior portion of the gill-slits behind. (The gill- slits are seen in our illustration below the A YOUNG BALANOGLOsSUS (much enlarged). collar.) In the ventral middle line, at the base of the proboscis, and concealed by the collar, is situated the mouth. Following behind the collar is the region of the trunk or body proper, which, in the adult of some species, reaches a relatively enormous length, even extending to 2 or 3 feet. The ectodermal covering of the body consists in general of ciliated cells, among which are scattered unicellular mucous glands; the cilia, however, appear to be more prominent on the proboscis than elsewhere. In the region of the trunk, which immediately follows upon the collar-region, there are a great number of paired openings on the dorsal side of the body placing the anterior portion of the digestive tract in communication with the outer world. These are the gill-slits, and they are arranged strictly in consecutive pairs to the number of upwards of fifty in the adult. In their structure, and more especially in the possession of tongue-bars, they bear a remarkable resemblance to the gill-slits of the lancelet. This is particularly striking in young individuals. As the adult form is approached in the development, the bulk of the gill-slits sinks below the 574. SEMIVERTEBRATES. surface, only opening at the latter by small sht-like pores, and thus their true character is obscured in superficial view.” On dissection, a rod-like structure, which arises as an outgrowth of the alimentary canal above the mouth, is seen projecting into the interior of the proboscis; and this rod has been identified with the vertebrate notochord. Above this rod, and extending farther back, is a dorsal nerve-chord, corresponding to the vertebrate nerve-tube, and having, as in the latter, a central canal, at least during the earlier stages of growth. Some distance behind the notochord this nerve-tube gives off a descending branch, connecting it with a similar chord lying on the ventral aspect of the animal. We thus have evidence of the existence in this strange worm-like creature of three essentially vertebrate characteristics, namely, gill-slits, a notochord, and a nerve-tube; and it is not a little remarkable that while in the sea-squirts the notochord is found in the transitory tail, in Balanoglossus it is situated in the anterior extremity, where it extends some distance in advance of the mouth. (Quite recently it has been shown that the tornaria-larva of one species of Bulano- glossus also possesses an entostyle (see p. 570), comparable to that of the lancelet and sea-squirts. That the creature under consideration is closely allied to the other Protochordates, and thus to the Vertebrates, may be considered fairly certain ; but there are also indications of affinity with Nonchordates. In the first place, while certain species of Balanoglossus pass through the earlier stages of their existence without undergoing a metamorphosis, in other kinds such a transforma- tion takes place; the young making its first appearance in the world in the form of what is known as a tornaria-larva, or one closely resembling that of a starfish. And it is held by competent naturalists that this resemblance must be indicative of some kind of genetic relationship between Balanoglossus on the one hand, and starfish and sea-urchins on the other. In the second place, there are not wanting indications of affinity with the so-called Nemertine worms, described in the next volume; these resemblances presenting themselves in the structure of the outer layer of the skin, the presence of a proboscis (kept retracted in the Nemertines), as well as in regard to the nervous system, the reproductive organs, and the alimentary canal. The two other forms included among the Protochordates are respectively known as Cephalodiscus and Rhabdoplewra, and bear the same relation to the last as is presented by the compound ascidians to the lancelet. Both these curious creatures are fixed forms, living in societies, repro- ducing their kind by means of buds, and having a U-shaped, instead of a straight, intestine. Both are likewise deep-water creatures, the former having been dredged in the Straits of Magellan at a depth of two hundred and forty-five fathoms, while the latter has been taken off the Shetlands in ninety, and off the Lofoten Islands in two hundred fathoms. Extremely minute in size, Cephalodiscus lives in colonies, the individuals wandering about the tubes of a common house, the walls of which are composed of a gelatinous material, covered with spiny projections, and perforated by numerous apertures for the free circulation of water. The mouth is overhung by a large shield-like plate, surmounted by the row of plume-like tentacles; while on the side of the body is a pedicle from which grow Other Forms. the buds; locomotion being probably effected by means of this pedicle and the ANCESTRY OF CHORDATES. 575 mouth-plate. The latter contains a short notochordal rod; and there is a single pair of gill-shts opening from the pharynx, water being passed into this from the mouth by the action of the tentacles. In the allied genus Rhabdoplewra the individuals which go to form a colony are connected with one another by means of a common stem, representing the remnants of their original contractile stalks ; this stem gradually drying up with the growth of the colony in the region most remote from the living polyps. Each polyp has but a single plume-like tentacle ; and the buds arising from the soft part of the common stem never become detached. While the nervous system and notochord are essentially the same as in Cephalodiscus, gill-slits are wanting. Ancestry of Before making a few brief remarks on this interesting but Chordates. perplexing subject, it may be mentioned that while we have no satisfactory clue as to the first origin of the notochord, it has been suggested that the original function of gill-slits was to carry off the superfluous water entering the mouth with the food; the connection with respiration being a later addition to these structures. It is also an important factor in the consideration of this subject to bear in mind that the whole of the existing Protochordates are to a greater or less extent degenerate types, although they doubtless retain some original and simple primitive features. For the proud position of the original ancestral stock, from which have sprung both Protochordates and Vertebrates, there are many Claimants; among these being segmented worms or annelids, creatures allied to the existing king-crab, and star-fishes and sea-urchins. With regard to the annelid theory, Mr. Willing very significantly remarks that in this case the doctrine of parallelism in development has not been sufficiently taken into account; and that the more complete the superficial resemblance between an Annelid and a Vertebrate, in the same measure is the parallelism in their developmental history the more striking, and their genetic affinity the more remote. Neither is it likely that the king-crab line of descent (in spite of the apparent identity in the structure of one layer of its shell with that of the Cephalaspidians) will hold good. The evidence in favour of an alliance between Vertebrates and Echinoderms (sea-urchins and star-fishes), through the intervention of Balanoglossus, seems, however, to be steadily gaining ground. Mr. Willey, for instance, remarks that while it is probable that the proximate ancestor of the Vertebrates was a free-swimming creature, intermediate in structure between an ascidian larva and the lancelet, the ultimate or primordial ancestor may be assumed to have been a worm-like animal, with an organisation approximately on a level with that of the bilaterally sym- metrical progenitors of the Echinoderms. Mr. Garstang also, having proved that the larvee of the whole of the latter group can be derived from a single common type, and likewise having shown that the tornaria-larva of Balanoglossus can be referred to the same modification, expressed an opinion that the Vertebrates also trace their origin to the same free-swimming pelagic form. Perhaps still more probability may attach to a later theory of the same observer, who now comes to the conclusion that Echinoderms, Enteropneusta, and Chordates are all divergent branches from a common unknown ancestor; such ancestor being a bilaterally symmetrical creature with the general appearance of a certain type (4 uricularia) of Echinoderm larva. From the hypothetical common stock the Echinoderms 576 SEMIVERTEBRATES. appear to have been derived by a series of changes mainly correlated with the assumption of their characteristic radial symmetry ; while the Chordates retained the original bilateral symmetry, at the same time undergoing certain changes, into the consideration of which it will be unnecessary to enter in this place. Still more complicated are the changes necessary to evolve Balanoglossus and its alles from the ancestral form. Such of our readers as are desirous of pursuing further this interesting subject, may be referred to the works of the observer last mentioned. A PYROSOMA-COLONY. In life the colony assumes a horizontal position. END Se VOL. V. on Ablepharus, 168. Amphibians, 257. Atlantosaurus, 35. Abramis, 463. Amphichelydia, 98. Au/liscops, 406. Acanthoclinide, 395. Amphicyon, 198, 202. Aulostoma, 406. Acanthoclinus, 395. Amphignathodontidx, 286. Aulostomatidx, 403. Acanthvas, 534. Amphiouus, 558. Australian Lung-Fish, 326. Acanthodactylus, 166. Amphipnous, 450. Axolotls, 299. Acanthodes, 548. Amphisbena, 158. Acanthodii, 315, 547. Amphisbenidx, 156. Badis, 352. Acanus, 340. Amphisile, 406. Baéna, 98. Acerina, 337. Amphiuma, 305. Bagarius, 454. Acichelyidex, 86. Aimphiunmide, 302. Bagrus, 456. Acipenser, 514. Anabantide, 409. Balistes, 427. Acipenseride, 514. Anabas, 410. ; Balistide, 427. Acris, 279. Anableps, 470. Balanoglossus, 573. Acrochordus, 198. Anacanthini, 430. Band-Fishes, 391. Acrodus, 532. Anacanthus, 427. Baptemys, 78. Acronuride, 362. Anaconda, 189. Barbel, 458. Acronurus, 363. Anarrhichas, 394. Barbus, 458. Actinistia, 518. Anchinia, 572. Barracuda Pike, 397. Actinopterygii, 315, 334. Anchovy, 491. Barracudas, 362, 397. Adders, 220. Ancistrodon, 243. Barramundi, 326. Banded, 221. Anelytropidx, 171. Basiliscus, 132. Death, 225. Angel-Fish, 535. Basilisks, 132. peut 235. Anglers, 378. Bass, 339. Resplendent, 220. Anguidex, 145. Batagur, 75. _Etheospondyli, 506. Anguilla, 446. Bathydraco, 375. Aétobatis, 544. Angwis, 147. Bathythrissidx, 485. Agama, 120. Anolis, 130. Batrachidx, 376. Agamas, 120. Anomalochilus, 196. Batrachopsis, 284. Armed, 120. Anomodonts, 254. Batrachus, 377. Rough-Tailed, 122. Anoplogaster, 355. Batrachyperus, 302. Spinose, 121. Antennarias, 380. Bdellostoma, 554. Agamide, 117. Anthias, 339. Beaked Fish, 474. Aylypha, 198. Aphyonus, 437. Beaked Guruards, 835 Agonus, 384. Apionichthys, 444. Beaked Lizards, 252 Alburnus, 465. Apoda, 309. Beaked Salmon, 481. Alepocephalidex, 491. Aporoscelis, 127. Bellia, 72. Alepocephalus, 491. Appendicularia, 572. Belone, 400. Alligator, 18. Arapaimas, 477. Belonorhynchus, 517. Alligators, 18. Arius, 454. 3erry-Bone Fishes, 330. Double-Tusked, 20. Armed Bull-Head, 384. Berychidx, 353. Alligator-Terrapin, 79. Arthrodira, 315, 330. Beryx, 354, 355. Alopecias, 526, Ascidia, 566. Betta, 4138. Alytes, 285. Ascidians, 561. | Bichir, 517. Amarucium, 568. Ascidiidx, 565. Bitterling, 462. Amblycephalidx, 229. Asp, 236. Bleak, 465. Amblyopsidx, 471. Aspidites, 186. Blennies, 391, 393. Aimblyopsis, 471. Aspidorhynchidex, 507. Blenniidx, 391, 393. Amblyrhynchus, 136. Asnidorhynchus, 507. Blennius, 394. Amblystoma, 299. Aspius, 464. Blind-Fish, 471. Ameiva, 156. Aspro, 336. Blind-Soles, 444. Amia, 508. Asteracanthus, 532. Blind-Worm, 147. Amiidex, 508. Astronesthes, 483. Blue Shark, 522, 523. Ammocetes, 552. Atherina, 397. Boa, 191. Ammodytes, 438. Atherinide, 397. Boidex, 181. VOL. V.—37 578 Boinx, 186. Boas, 187. Dog-Headed, 189. Keeled, 189. Tree, 187. True, 191. Bolieria, 195. Bombinator, 284. Bony Fishes, 333. Bony Pike, 506, 507. Bow-Fin, 508. Botryllidx, 567. Botrylloides, 568. Botryllus, 568. Box, 347. Brachydirus, 331. Brachylophus, 140. Branchiostonva, 558. Branchiostonatidex, 558. Bream, 463. Brontosaurus, 35. Brookesia, 172. Brosmius, 437. Brotula, 437. Bufo, 277. Bufonide, 276. Bull-Heads, 380, 381. Bungarus, 22). Burbot, 435. Bushmaster, 248. Cachuga, 74. Caimans, 15. Caiman, 17. Calabaria, 186. Calamoichthys, 517. Californian Toad, 142. Callagur, 75. Callichthys, 455. Callionymus, 491. Callorhynchus, 332. Callophis, 220. Calotes, 119. Canthurus, 347. * Cantoria, 218. Carangidx, 363. Caranx, 363, 364. Carassius, 458. Carcharias, 522, 523. Carchariidz, 522. Carcharodon, 526. Carettochelyidx, 97. Carettochelys, 97. Carps, 456. Beaked, 462. Crucian, 458. Golden, 458. True, 456. Casarea, 193. Cat-Fishes, 452. Fel-Like, 454. Electric, 455. Mailed, 456. Yarrell’s, 454. Caturus, 509. Caudata, 289. Cave-Fish, 437. Centrarchidx, 338, Centrarchus, 338. Centriscidx, 403. Centriscus, 406. Centrogenys, 338, INDEX. Centrophorus, 534. Centropristis, 339. Cephalaspis, 556. Cephalodiscus, 574. Cephaloptera, 544. Cepola, 391. Cepolidx, 391. Cerastes, 236. Ceraterpetum, 313. Ceratobatrachidx, 273. Ceratobatrachus, 273. Ceratodus, 326. Ceratophrys, 274. Ceratops, 39. Cestracion, 530. Cestraciontide, 530. Cetorhinus, 527. Chetodon, 343. Chetodontide, 343. Chalcides, 170. Chameleon, 172. Chameleons, 171. Chameleontidx, 172. Chamesaurus, 144. Channa, 408. Characinidex, 468. Characinus, 468. Charina, 195. Charr, 561. Chauliodus, 483. Chelmon, 343. Chelodina, 93. Chelone, 82. Chelonia, 42. Chelonidx, 81. Chelydra, 79. Chelydridx, 78. Chelyidx, 88. Chelys, 90. Chersydrus, 199. Chilodactylus, 351. Chiloscyllium, 530. Chimera, 331. Chimexridex, 331. Chimeroids, 315, 331. Chioglossa, 294. Chiridz, 392. Chirocentridx, 484. Chirocentrus, 484. Chirotes, 157. Chirus, 392. Chisel-Jaw, 480. Chitra, 100. Chlamydosaurus, 123. Chiamydoselache, 532. Chologaster, 472. Chondropython, 186. Chondrostet, 510. Chondrosteus, 516. Chondrostoma, 462. Choridactylus, 351. Chorinemus, 350. Chromididx, 418, 422. Chromis, 423. Chrysemys, 73. Chrysichthys, 455. Chthonerpetum, 310. Chub, 459. Cladocyclus, 397. Cladodontia, 546. Cladoselache, 547. Claosaurus, 38. Clarias, 454. Claudius, 78. Clavelina, 567. Clavellinide, 567. Clemmys, 70. Clidastes, 249. Climbing-Perch, 410. Clupea, 486. Clupeidx, 486. Cimoliosaurus, 102. Cinosternidx, 77. Cinosternum, 77. Cinixys, 63. Cirrhites, 350. Cirrhitichthys, 350. Cirrhitidz, 349. Cistudo, 66. Coal-Fish, 434. Cobitis, 467. Cobras, 222. Coccosteidx, 331. Coccosteus, 330. Cod Tribe, 431. Cecilia, 310. Ceciliidez, 309. Celacanthus, 518. Coffer-Fishes, 427, 428. Coilia, 491. Coluber, 209. Colubridz, 198. Comb-Gilled Fishes, 423, 427. Comephorus, 396. Compsognatius, 36. Conger, 449. Conolophus, 137. Conyrodus, 439. Corallus, 189. Coronella, 205, 209. Coryphena, 368. Coryphenidx, 368. Corythophanes, 134. Coltidz, 386. Cottus, 381. Craitsie2 21 Crenidens, 347. Crocodiles, 10. Earlier, 32. Estuarine, 22. Existing, 15. Indian, 21. Long-Nosed, 27. Nile, 24. Orinoco, 27. Sharp-Nosed, 26. Siam, 25. Stumpy, 20. True, 21. Crocodilia, 10. Crocodilidx, 15. Crocodilus, 21. Crossopterygii, 315, 333 517. Crotalus, 239. Cryptobranchus, 304. Cryptedira, 89. Ctenosaura, 141. Curtidzx, 355. Curtus, 355. Cybium, 371. Cyclanorbis, 100. Cyclemys, 66. Cycloderma, 100. Cyclomyaria, 572. Cyclopteridx, 386. Cyclopterus, 387. Cyclosalpa, 572. Cyclostomata, 549. Cyclura, 140. Cynodon, 469. Cynthiide, 565. Cyprinidex, 456. Cyprinodon, 470. Cyprinodontidx, 469. Cyprinus, 456. Cyttide, 366. Cyttus, 367. Daetylopteridx, 384. Dactylopterus, 385. Dace, 460. Damonia, 72. Danubian Perches, 336. Dapedius, 510. Dapedoglossus, 477. Dasypeltis, 214. Dendrelaphis, 214. Dendrobutes, 271. Dendrobatidx, 271. Dendrophis, 214. Dendrophryniscidxe, 276. Dentice, 348. Dermatemydide, 77. Dermatemys, 78. Desmognathus, 302. Devil-Fish, 548. Dibamidex, 171. Dicamptodon, 302. Dicerobatis, 544. Dicynodonts, 255. Dinosauria, 33. Dinosaurs, 33. Armoured, 38. Bird-Like Group, 36. Carnivorous Group, 35. Horned, 38. Lizard-Footed Group, 34. Diodon, 429. Diodontidex, 428. Dipnoi, 315, 326. Diplacanthus, 548. Diplocynodon, 20. Diplomystus, 490. Dipsas, 217. Discoglossidx, 284. Discoglossus, 284. Distira, 229. Ditrema, 422. Ditrematidex, 421. Dog-Fishes, 529, 530. Spiny, 533. Dolichosauria, 249. Dolichosoma, 313. Dolioluwm, 572. Dorab, 484. Doras, 455. Dories, 366. Doryichthys, 425. Double-Eyes, 470. Draco, 118. Dragonets, 391. Dragon-Fish, 386. Drum, 356. Dryophis, 217. Eagle-Rays, 543. INDEX. Ecaudata, 257. Echeneis, 371. Echiostoma, 483. Echis, 238. Edaphodon, 332. EKel-Pout, 435. Kels, 445. Conger, 449. Deep-Sea, 449. Electric, 451. Serpent, 449. Short-Tailed, 450. Single-Slit, 450. Spiny, 395. True, 446. Eja, 237. Elacate, 371. Elaps, 218. Elasmobranchii, 315. Elasmodus, 332. Electric Eel, 451. Electric Rays, 542. Elops, 491. Elseya, 93. Emperor-Fish, 344 Emyda, 100. Emydura, 93. Emys, 68. Encheliophis, 438. Engraulis, 491. Engystoma, 271. Engystomatide, 271. Enteropneusta, 573. Enygrus, 189. Eosphargis, 88. Epicrates, 188. Erythrinidx, 468. Eryx, 194. Escuerzos, 275. Esocide, 473. Esox, 473. Eublepharis, 116. Euneces, 191. Eustomias, 484. Exonegas, 553. Fan-Finned Fishes, 334. Feather-Backs, 475. Fer-de-Lance, 248. Ferreiro, 281. Fierasfer, 438. Fighting-Fish, 413. File-Fishes, 427. Firm-Fin, 350. Fishes, 314. Fish-Lizards, 250. Fistularia, 406. Flat-Fishes, 439. Flounder, 443. Flute-Mouths, 403, 405. Flying-Dragons, 39. Flying-Fish, 400, 401. Flying-Gurnards, 384. Fold-Finned Sharks, 546. Fringe-Finned Ganoids, 517. Frog-Fishes, 376, 377. Frogs, 257, 265. Agile, 266. Antillian, 276. Bull, 268. Common, 2 Darwin’s, 272. 579 Frogs-—continued. Disc-Tongued, 284, Edible, 266. European, 266. Extinct, 284. Fire-Bellied, 284. Flying, 269. Grasshopper, 279. Guppy’s, 268. Horned, 274. Leaf, 276. Midwife, 285. Montezuma’s, 268. Moor, 266. Narrow-Mouthed, 271. Piping, 276. Pouched, 282, Sharp-Nosed, 278. Short-Headed, 272. Southern, 273. Spur-Toed, 286. Tongueless, 286. Tree, 271, 279. Typical, 265. Water, 265. Gadidx, 431. Gadus, 433. Galesaur, 255, Galeus, 524. Garial, 30. Extinct, 31. Schlegel’s, 29. Garialis, 30. Gar-Pike, 400. Gastrochisma, 369. Gastrosteidx, 403. Gastrosteus, 403. Geckonidzx, 110. Geckos, 110. Eyelid, 116. - Fringed, 114. Lobe-Footed, 112. Turkish, 112. Wall, 114. Gegenophis, 310. Genypterus, 438. Geoémyda, 64. Geotria, 553. Gerrohonotus, 146. Gilt-Heads, 348. Glauconia, 180. Glauconiidx, 180. Globe-Fishes, 428. Gobies, 388. Gobiidx, 388. Gobio, 459. Gobius, 388. Gobioesocide, 407. Gobioesox, 408. Fongylophis, 195. Goniognathus, 369. Goniopholis, 32. Gonorhynchidx, 481. Gonorhynchus, 481. Grayling, 505. Grey Mullets, 399. Gudgeons, 459. Gurami, 412. Gurnards, 380, 382. Gymnarchus, 475. Gymnelis, 431. 580 Gymnoscopelus, 482. Gymnotide, 445. Gymnotus, 451. Gyroptychius, 519. Haddock, 433. Hag-Fishes, 550, 553. Hair-Tails, 362. Hairy-Backs, 392. Hake, 435. Halargyreus, 435. Half-Beaks, 401. Haliophis, 439. Hamadryad, 223. Hammer-Headed Shark, 524. Haplochiton, 492. Haplochitonidx, 491. Haplodactylus, 347. Hardella, 75. Harottia, 332. Hausen, 515. Hedgehog-Mouths, 483. Helicops, 204. Hell-Bender, 304. Helminthophis, 180. Heloderma, 148. Helodermatidx, 148. Hemerocoétes, 392. Hemibungarus, 221. Hemichelys, 97. Hemimyaria, 570. Hemiphractidx, 286. Hemirhamphus, 401. Hemirhynchus, 362. Fleniochus, 344. Herrings, 486, 487, 490. Heterocarpus, 422. Heterocephalus, 239. Heterotis, 478. Hippocampus, 426. Hippoglossus, 442. Histiophorus, 358. Holacanthus, 344. Holocentrum, 354. Holocephali, 315, 326, 331. Holoptychius, 519. Holibut, 442. Homatopsis, 218. Homalopterus, 456. Homeosaurus, 254. Homopus, 62. Hoplognathidx, 349. Hoplognathus, 349. Hoplosaurus, 35. Horned Lizards, 142. Horse-Mackerels, 363. Hybodus, 532. Hydraspis, 93. Hydrocyon, 469. Hydromedusa, 92. Hydrophis, 228. Hydrus, 228. Hylxobatrachus, 300. Hulzxochelys, 97. Hylidx, 279. Hyla, 280. Hylodes, 276. Hylonomus, 313. Hypnobius, 302. Hyodon, 479. FHyodontidx, 479. Hyperodapedon, 254. INDEX. Hypobythius, 566. Ichthyophis, 310. Ichthyopterygia, 250. Ichthyosaurs, 250. Ichthyoscopus, 375. Ichthyotomi, 315, 545. Ide, 460. Iguana, 139. Iguanas, 128. Black, 141. Extinct, 142. Fijian, 140. Ring-Tailed, 140. True, 139. Iquanavus, 142. Iquanidx, 128. Iguanodons, 37. Ilysia, 195. Ilystidx, 195. Ischnacanthus, 548. Isospondyli, 475. Jacares, 16. Jacuaru, 154. Jararaca, 248. Knerria, 468. Knerriidx, 468. Knife-Jawed Fishes, 349. Kreuzotter, 230. Labaria, 248. Labridx, 418, 419. Labrus, 419. Labyrinth-Gilled Fishes, 409. Labyrinthodontia, 311, Lacerta, 159. Lacertidx, 158. Lacertilia, 104. Lachesis, 243. Lemargus, 334, Lamna, 526. Lamnidx, 525. Lampreys, 549, 550. Lampris, 368. Lancelets, 558. Lariosaur, 103. Larvacea, 572. Lates, 340. Latilide, 375. Latilus, 375. Latris, 351. Latrunculus, 389. Leathery Turtles, 86. Lepadogaster, 407. Lepidocottus, 381. Lepidopus, 360. Lepidosiren, 328. Lepidosirenidx, 326. Lepidostcidx, 506. Lepidosteus, 507. Lepidotus, 510. Leptocardii, 558. Leptodactylidx, 2 Leptodactylus, 27 Leptolepis, 491. Leptoscopus, 375. Leucaspius, 466, Leuciscus, 459. Lialis, 116. LDiasis, 186. Lichanura, 195. Light Fish, 482. Ling, 436. Liodesmus, 509. Liodon, 249. Lizards, 104. Agamoid, 107. Anolis, 130. Australian Frilled, 122, Beaked, 252. Bronze, 170. Ceylon Horned, 120. Flying, 118. Fringe-Toed, 166. Galapagos, 135, 137. Girdled, 143. Greaved, 153. Green, 160. Horned, 142. Keeled, 165. Long-Necked, 249. Moloch, 127. Oriental Tree, 119. Pearly, 159. Poisonous, 148. Ridge-headed, 134. Sail-Tailed, 123. Scale-Footed, 116. Sea, 135. Snake-Eyed, 168. Snake-Like, 145. Stilted, 134. Stump-Tailed, 167. Thorny-Tailed, 124, 127. True, 158. Viviparous, 162. Wall, 163. Loaches, 466. African, 468. Lobe-Finned Sharks, 546. Loggerhead, 83. Long-Finned Herring, 485. Long-Fins, 351. Long-Tails, 439. Lophiide, 379. Lophius, 379. Lophobranchii, 423. Lopholatitus, 375. Lophotes, 414. Lophotidex, 414. Lophurus, 123. Loricaria, 455. Lota, 435. Loxocemus, 186. Lucifuga, 437. Luciocephalide, 409. Luciocephalus, 414. Lucioperca, 336. Lump-Suckers, 386. Lung-Fishes, 315, 326. Luth, 86. Lycodes, 431. Lycodidx, 430. Lytoloma, 86. Mackerels, 369. Macroclemnrys, 80. Macrones, 455. Macruridx, 439. Macrurus, 439. Mailed-Tube-Mouths, 423. Malacanthidex, 376. Malacanthus, 376. Malacoclemmys, 72. Malacosteus, 484. Malapterurus, 455. Mantella, 271. Many-Rayed Salmon, 502. Marane, 504, 505. Marsipobranchii, 550. Mastodonsaurus, 313. Matamata, 90. Meagres, 357. Megalobatrachus, 302. Megalosaurus, 35. Megalurus, 509. Melamphexes, 354. Mene, 369. Merluccius, 435. Metoposaurus, 313. Metriorhynchus, 32. Microcosmus, 565. Minnow, 461. Miolania, 97. Miolaniide, 97. Misgurnus, 467. Molge, 294. Moloch, 127. Molva, 436. Monacanthus, 427. Monitors, 149. Monk-Fish, 535. Monocirrhus, 352. Monopterus, 451. Moon- Eye, 479. Mordacia, 553. Morelia, 184. Morenia, 74. Mormyridx, 474. Mormyrus, 474. Morone, 339. Mosasaurus, 249. Mud-Fish, 328. Mud-Skippers, 389. Mugil, 399. Mugilidx, 397. Mullets, 345, 399. Grey, 399. ted, 345. Mullidx, 345. Mullus, 345. Murena, 445. Murexnidex, 445. Mustelus, 524. Myliobatidx, 5438. Myliobatis, 543. Myriacanthide, 332. Myripristis, 354. Myxine, 554. Myxinide, 554. Naia, 222. Nandidex, 352. Nandus, 352. Nardoa, 186. Naucrates, 365. Nectes, 277. Nectophryne, 277. Necturus, 308. Nemachilus, 467. Nematognathi, 452. Nemichihys, 450. Nerophis, 425. Newts, 289, 295. Alpine, 296. See Oe eee OE ES SS Eee INDEX. Newts—continued. Banded, 297. Common, 296. Crested, 295. Marbled, 296. Waltli’s, 297. Webbed, 296. Nicoria, 64. Nomexide, 369. Nomeus, 369. Notacanthidex, 417. Notacanthus, 417. Nothopsis, 199. Notidanus, 532. Notidanidex, 532. Notogoneus, 481. Notopteridx, 475. Notopterus, 475. Notothenia, 376. Nototrema, 282. Oblique-Spined Blenny, 395. Ocadia, 74. Oil-Fish, 396, Olm, 307. Onchorhynchus, 502. Onychodactylus, 302. Ophichthys, 445, 449. Ophidia, 174. Ophidiidx, 437. Ophidium, 438. Ophiocephalidx, 408. Ophiocephalus, 408. Ophisaurus, 146. Opisthoglypha, 198. Ornithosauria, 39. Orodus, 532. Orthagoriscus, 430. Osmerus, 503. Osphromenus, 412. Osteoglosside, 477. Osteoglossum, 478. Osteolemus, 20. Ostracion, 428. Ostracophori, 555. Oxybelis, 218. Oxyglossus, 269. Pachytriton, 299. Pagellus, 346. Pagrus, 348. Palxobatrachidx, 284. Palxobatrachus, 284. Palxohatteria, 254. Palxoniscus, 517. Palxophis, 195. Palxorhynchide, 362. Palzxorhynchus, 362. Palexosiren, 313. Palxospondylus, 554. Pantodon, 480. Pantodontidx, 479. Paradise-Fish, 411. Paraperca, 336. Parasitic-Fish, 438. Pariasaurians, 255. Parrot- Wrasses, 421. Pegasus, 386. Pelagosaurus, 32. Pelecus, 466. Pelamys, 371. Pelobates, 283. Pelobatidx, 283. Pelochelys, 100. Pelodytes, 284. Pelomedusa, 97. Pelomedusidx, 88, 94. Pelor, 351. Pelorosaurus, 35. Pelosaurus, 313. Pempheris, 355. Perca, 335. Percarina, 337. Perch, African, 340. Oriental, 340. Sea, 339. South American, 338. Perch Tribe, 335. Percichthys, 338. Percidx, 335. Perciformes, 335. Periophthalinus, 389. Peristethus, 385. Petalopteryx, 384. Petalodontidx, 535. Petalodus, 535. Petromyzidx, 551. Petromyzwm, 551. Phallusia, 565. Philodryas, 217. Phosphorescent Fishes, 482. Photichthys, 482. Phrynocephalus, 122. Phrynosoma, 142. Phyllodus, 419. Phyllopteryx, 426. Physoclysti, 334. Physostomi, 444. Pike, 473. Pike-Head, 414. Pike-Perches, 336. Pilchard, 489. Pilot-Fish, 365. Pimelodus, 454. Pinguipes, 376. Pipa, 286. Pipidx, 287. Pipe-Fishes, 424. Plagyodus, 482. Plaice, 443. Platax, 366. Platemys, 93. Platurus, 227. Platysomatidex, 517. Platysomus, 517. Platysternidx, 75. Platysternum, 75 Plectispondyli, 456. Plectognathi, 423, 427. Plesiochelyidx, 97. Plesiochelys, 97. Plesiops, 352. Plesiosauridx, 102. Plesiosaurus, 102. Plethodon, 302. Pleuracanthus, 546. Pleurodira, 88. Pleuronectes, 439, 443. Plewronectidx, 439. Pleurosternum, 98. Pliosaurus, 103. Podoenemis, 93. | Podoeys, 340. 581 582 Pogonias, 356. Pollan, 504. Polyacanthus, 411. Polycentridx, 352. - Polycentrus, 352. Polyclinidex, 568. Polynemidex, 355. Polynemus, 356. Polyodon, 513. Polyodontidx, 513. Polypedates, 270. Polyprion, 340. Polypteridx, 517. Polypterus, 517. Pomacentridx, 418. Pomacentrus, 418. Porbeagle, 525, 526. Portheus, 486. Port Jackson Shark, 5380. Powan, 504. Power-Cod, 434. Primeval Salamanders, 311. Prionurus, 363. Pristidzx, 535. Pristiophoridx, 585. Pristiophorus, 536. Pristipoma, 340. Pristis, 536. Propseudopus, 147. Proteidx, 306. Proteus, 307. Proteroglypha, 198, 218. Proterosaurus, 254. Protochordata, 549, 550, 558. Protopterus, 329. Protosphargis, 88. Protostega, 88. Prototroctes, 492. Protriton, 318. Psammodromus, 165. Psammoperca, 340. Psephophorus, 88. Psephurus, 5138. Psettodes, 442. Psettus, 366. Pseudechis, 225. Pscudobranchus, 309. Pseudochromis, 376. Pteraspis, 555. Pterichthys, 556. Pterodactyles, 39. Pterodactylus, 41. Pterots, 351. Pteroplatea, 545. Ptyas, 208. Ptychozowm, 114. Ptyodactylus, 112. Pyctodus, 332. Pygopodidx, 116. Pygopus, 117. Pyrosoma, 569. Pyrosomatide, 569. Python, 182. Pythoninex, 132. Pythonomorpha, 249. Pythons, 181. Amethystine, 184. Anchieta’s, 186. Indian, 182, 186. Reticulated, 184. Royal, 186. Timor, 164. INDEX. Pythons—continued. True, 182. West African, 182, 185. Pyxis, 64. Raia, 541. Ratide, 541. Raj-Samp, 221. Rana, 265. Ranidx, 265. Ranidens, 302. Rapfen, 464. Rattle-Snakes, 238. Common, 239. Diamond, 240. South American, 240, Rays, 520. Beaked, 538. Eagle, 543. Electric, 542. Halavi, 539. Sting, 545. True, 541. Red Mullets, 345. Reed-Fish, 517. Regalecus, 416. Reptiles, 1. Rhabdopleura, 574. Lhacholepis, 491. thacophorus, 270. thampholean, 172. Rhamphorhynchus, 41. Lhamphosuchus, 31. Rhinechis, 212. Rhinemys, 98. Rhinobatidx, 538. Rhinobatis, 539. Rhinodon, 527. Rhinodontidx, 527. Rhinophrynus, 277. Rhinoptera, 544. Rhipidistia, 518. Rhiptoglossa, 171. Rhodeus, 462. Rhynchobatis, 540. Rhynehobdella, 396. Rhynchobdellidx, 395. Rhynchocephalia, 252. Rhynchosaurus, 254. Rhynchosuchus, 29. Ribbon-Fish, 414, 415. Rita, 455. Roach, 459. Rockling, 436. Ruffes, 337. Saccopharynx, 449. Saccostomus, 239. Sebling, 501. Salamanders, 289, 291. Alpine, 293. Black, 2938. Eel-Like, 305. Fish-Like, 302. Giant, 302. Gilled, 306. Mississippi, 304. Primeval, 310. Siren, 309. Spanish, 294. Spectacled, 298. Spotted, 291. Salamanders-—continued. ’Three-Toed, 305. Two-Legged, 308. Typical, 291. Salamandra, 291. Salamandridx, 291. Salamandrella, 302. Salamandrina, 298. Salamandring, 291. Salmo, 494. Salmon, 493, 495. Beaked, 480. Salmonidx, 493. Salpa, 572. Salpidx, 570. Sand-Eels, 437, 438. Sand-Smelts, 397. Sardine, 489. Sargus, 347. Saurocephalidx, 486. Saurocephalus, 486. Saurodonts, 486. Sauropterygia, 101. Saury, 401. Saw-Fishes, 535. Scabbard-Fish, 360. Scaled Reptiles, 104. Scaly-Finned Fishes, 343. Scaphiopus, 283. Scaphirhynchus, 516. Scarus, 421. Scatharus, 347. Scatophagus, 344. Scheltopusiks, 146. Schneepel, 504. Seiwna, 357. Scieanidex, 356. Scincidx, 166. Scincus, 169. Scomber, 369. Scomberidx, 369. Scombresocidx, 400. Scombresox, 401. Scopelidx, 481. Scopelus, 481. Scorpena, 351. Scorpenidex, 351. Scorpxnoids, 351. Scylliidx, 529. Scylliwm, 530. Sea-Bats, 366. Sea-Breams, 346. Sea-Horses, 424, Sea-Perch, 339. Sea-Snakes, 226. Sea-Squirts, 561. Sebastes, 351. Selachoidei, 315. Semivertebrates, 549, 550. Serpent-Eels, 449. Serpent-Heads, 408. NSerranidex, 338. Serranus, 339. Serrasalmo, 468. Shad, 489. Sharks, 520. Basking, 527. Blue, 522, 523. Comb-Toothed, 533. Fold-Finned, 546. Fox, 526. Frill-Gilled, 533. Sharks—continued. Greenland, 534. Hammer- Headed, 524. Hound, 524. Pavement-Toothed, 530. Porbeagle, 525, 526. Port Jackson, 530. Rondeleti’s, 526. Spiny, 535. Thresher, 526. Sharks and Rays, 315. Sheath-Fishes, 452. Sichel, 466. Side-Necked Tortoises, 88. Siluridx, 452. Silurus, 454. Siphonostoma, 424. Siren, 309. Sirenoidea, 326. Sirenoidet, 315. Skates, 541. Skinks, 166. Common, 167. True, 169. Slime-Heads, 353. Smelts, 503. Smooth-Heads, 491. Snake-Fishes, 438. Snakes, 174. JEsculapian, 209. Back-Fanged Tree, 217. Blind, 180. Bushmaster, 248. Cat, 216. Chain, 209. Climbing, 209. Colubrine, 198. Copper-Head, 245. Coral, 218. Coral Cylinder, 195. Cylinder, 195. Dark Green, 206. Diamond, 184. Barth, 197. Egg-Eating, 214. Fierce, 206. Four-Lined, 210. Four-Rayed, 211. Garter, 203. Green, 217. Horseshoe, 207. Keel-Tailed, 204. Leopard, 210. Moceasin, 203, 245. Moon, 215. Nocturnal Tree, 217. Oblique-Eyed, 203. Oriental Freshwater, 218. Pantherine, 208. Pigmy, 204. iat 207. Rattle, 238. Red, 196. Ringed, 200. Running, 208. Sand, 193. Sea, 226. Sharp-Nosed, 218. Shield-Tailed, 197. Sling, 205. Smooth, 205. Tree, 214, 217. INDEX: Snakes—continued. True, 158. Viperine, 201. Wart, 198. Water, 200. Whip, 217. Wood, 213. Snappers, 78. Temminck’s, 80. Soft-Finned Fishes, 430. Soft-Spines, 376. Soft-Tortoises, 98. Cantor’s, 100. Granulated, 100. Solea, 448. NSolenostoma, 423. Solenostomatidxe, 423, Soleoltalpa, 444. Soles, 443. Southern Salmon, 491. Sparidx, 346. Spear-bBeaks, 567. Spelerpes, 302. Sphenodon, 252. Sphyrena, 397. Sphyrenide, 397. Sphyrna, 524. Spinacide, 533. Spinax, 534. Spine-Finned Fishes, 334. Spine-Finned Sharks, 547. Spiny Eels, 395. Sprat, 489. ~ Squaloraia, 332. Squaloratidx, 352. Squamata, 104. Square-Tail, 398. Squatina, 535. Squatinide, 535. Star-Gazers, 373, 374. Staurotypus, 78. Stegostoma, 530. Steneosaurus, 32. Steneoptychidx, 482. Sternotherus, 97. Sticklebacks, 403. Sting-Bull, 375. Stolickzaia, 199. Stomateidx, 482. Stonias, 483. Stromateidx, 367. Stromateus, 367. Sturgeons, 510 Giant, 514. Shovel-Beaked, 516. Slender-Beaked, 513. Toothed, 513. Toothless, 514. True, 514. Stylophorus, 416. Sucker-Fishes, 407. Sucking-Fishes, 371. Sun-Fish, 368. Sun-Fishes, 428, 430. Suravi, 455. Surgeons, 362. Sword-Fishes, 357. Symbranchidx, 445, 450. Symbranchus, 451. Synaphobranchus, 449. Synechodus, 532. Syngnathidx, 424. Syngnathus, 424. Tarbophis, 216. Tarentola, 114. Tautoga, 419, 421. Tetidx, 153. Teju, 154. Teleostomi, 315, 333. Tench, 461. Tentacle-Fish, 380. Terrapins, 64, 70. Alligator, 79. Caspian, 71. Chaibassa, 65. Chinese, 74. Eyed, 74. Hamilton’s, 72. Hinged, 66. Japanese, 71. Land, 64. Maw’s, 78. Mud, 77. Painted, 73. Pennsylvanian, 77. Salt-Water, 72. Sculptured, 70. Spanish, 71. Spinose Land, 65. Thick-Necked, 72. Three-Keeled, 65. Testudinidex, 47. Testudo, 49. Tetragonurus, 398. Tetrodon, 429. Teuthididex, 353. Teuthis, 353. Thalassochelys, 83. Thaliacea, 570. Theriodonts, 255. Thick-Rayed Fishes, 349. Thoracosaurus, 31. Thorius, 302. Thornbacks, 417. Thorny-Nose, 392. Thresher, 526. Thrissops, 491. Thymallus, 505. Thynnus, 370. Thyrsites, 362. Tile-Fish, 375. Tinca, 461. Toad-Frogs, 283. Brown, 283. Toads, 257, 276. Common, 277. Green, 278. Natterjack, 278. Sharp-Nosed, 279. Surinam Water, 287. True, 277. Tope, 524. Torpedinidex, 542. Torpedo, 543. Torsk, 437. Tortoises, 41. Aldabra, 56. Amazonian, 94. Angulated, 61. Areolated, 62. Big-Headed 73. Box, 66. Brazilian, 49. Burmese Brown, 50. 583 584 Tortoises—continued. Carolina, 66. Elegant, 51. Elongated, 61. Florida, 49. Forsten’s, 61. Galapagos, 57. Giant, 55. Greaved, 93. Grecian, 59. Hinged, 62. Horned, 97. Horsfield’s, 61. Land, 47. Long-Necked, 93. Mascarene, 57. Matamata, 90. Pond, 68. S-necked, 89. Side-Necked, 92. Snake-Necked, 92. Soft, 98. Spider, 64. Wide-Shielded, 98. Toxotes, 344. Trachichthys, 354. Trachinidx, 373. Trachinops, 352. Trachinus, 375. Trachodons, 37. Trachyboa, 189. Trachypteridx, 414. Trachypterus, 416. Trachysaurus, 167. Tree-Frogs, 271, 279. European, 280. Pouched, 282. Typical, 280. Triacanthus, 427. Trichiurichthys, 360. Trichiuride, 360. Trichiurus, 362. Trichonotidx, 392. Trichonotus, 392. Trigia, 382. Trigonorhina, 546. INDEX. Trimeresaurus, 247. Triodon, 428. Trionychidex, 98. Trionyx, 99. Tropidonotus, 200. Trumpet-Fish, 403, 406. Trygon, 545. Trygonidey, 545. Tuatera, 252. | Tube-Bladdered Fishes, 444. Tuft-Gilled Fishes, 4238. Tunicata, 561. Tunnies, 370. Tupinambis, 154. Turbot, 442. Turtles, 81. Extinct, 86. Green, 82. Hawksbill, 82. Leathery, 86. Loggerhead, 83. Tylotriton, 299. Typhlichthys, 471. Typhilonectes, 310. Typhlonus, 437. Typhlophis, 180. Typhlopidx, 180. Typhlops, 180. Umbra, 472. Umbres, 472. Umbridx, 472. Umbrina, 357. Undina, 518. Ungalia, 189. Ungaliophis, 189. Unicorn-Fish, 414. Uraniscodon, 134. Uranoscopus, 374. Urogymnus, 545. Urolophus, 545. Uromastix, 125. Uronectes, 431. Uropeltidx, 197. Varanide, 149. MORRISON AND GIBB, PRINTERS, EDINBURGH. OT) Varanus, 149. Vendace, 504. Vipera, 230. Viperidx, 229. Vipers, 229. Common, 2380. Desert Saw, 237. Halys, 243. Horned, 236. Long-Nosed, 233. Pit, 246. Rattle, 238. Russell’s, 234. Sand, 233. Southern, 230. True, 230. Water, 246. Viviparous Blennies, 394. Weavers, 3738, 375. Wels, 454. White-Fish, 459. Whiting, 434. Whiting-Pollack, 434. Whiting-Pout, 434. Wolf-Fish, 394. Wrasses, 418, 419. Parrot, 421. Viviparous, 421. Xenodermus, 199. Xenopeltidex, 198. Xenopeltis, 198. Xenopodidx, 286. Xenopus, 286. Xiphias, 358. Xiphiide, 357. Xiphocercus, 132. Zamenis, 206. Zarthe, 463. Zebra-Fish, 344. Zoarces, 394. Zonuridex, 143. Zonurus, 144 Zope, 463. ey mh PAS ue ? a8 : ae oo = . race re a