m

BIOLOGY

LIBRARY

G

C ASSELL'S

NATURAL HISTORY

EDITED BY

P. MARTIN DUNCAN, M.B. (LOND.), F.R.S., F.G.S.

PROFESSOR OF GEOLOGY IN AND HONORARY FELLOW OF KING'S COLLEGE, LONDON J CORRESPONDENT OF THE ACADEMY OF NATURAL SCIENCES, PHILADELPHIA

VOL. V

ILL USTRA TED

CASSELL AND COMPANY, LIMITED

LONDON, PARIS & MELBOURNE

1895

ALL RIGHTS RESERVED

PISCES.

PROFESSOR H. G. SEELEY, F.R.S., F.G.S., ETC.

INVERTEBRATA (INTRODUCTION).

PROFESSOR P. MARTIN DUNCAN, M.B. (LoxD.), F.R.S., F.G.S., ETC.

MOLLUSCA.

HENRY WOODWARD, LL.D., F.R.S., F.G.S., ETC.

TUNICATA.

HENRY WOODWARD, LL.D, F.R.S., F.G.S., ETC.

MOLLUSCOIDA (BRACHIOPODA AND BRYOZOA).

AGNES CRANE.

INSECTA (INTRODUCTION).

W. S. DALLAS, F.L.8.

COLEOPTERA.

H. W. BATES, F.L.S.

p>

* ' ''

HYMENOPTERA.

W. S. DALLAS, F.L.S.

CO^TEJSTTS

CLASS PISCES. -FISHES. CHAPTER I.

GENERAL INTRODUCTION THE ANATOMY AND OTHEH CHARACTERISTICS OF FISHES.

PAGE

Immense Variety of Forms Characteristics of the Class Industrial Importance to Man Fecundity— Colour Mental Endowments— Their General Structure— The Lowest Type of Fish Structural Features in Sharks and Rays The Skull Peculiarities in the Lepidosiren Skull of Codfish The Sense Capsules Teeth and Jaws The Branchial Arches— The Muscles of Fishes The Skin and Mucous System To what Causes the Colour of Fishes is Due— The Scales of Fishes Agassiz's Classification based on Scales The Nervous System The Spinal Cord— The Brain— Organs of Smell, Sight, and Hearing— The Electric Organs— The Teeth of Fishes— The Alimentary Canal— The Liver— The Air-bladder— The Blood— The Heart— The Gills— Fins and their Functions- Classification of the Fishes 1

CHAPTER II.

THE PAL.EICHTHYES, OR FISHES OK ANCIENT TYPES.

DIPNOI, OR MUD -FISHES— Why this Order is Interesting— THE AFRICAN MUD-FISH— THE SOUTH AMERICAN MUD-FISH— THE GENUS CERATODUS— GANOIDEI, OR FISHES WITH BONY SCALES— THE AuuvjE—Amia, cahu—THE BONY PIKE OF THE NILE— THE AMERICAN BONY PIKE— Its Remarkable Characters -HOLOCE- PHALA— The Chinuera vwnstwsa—Tke Genus Callorhynchus— PLAGIOSTOMATA— The Sharks and Rays— SELACHOIDEI— THE BLUE SHARK— Its Habits— Muscular Vitality— Economic Uses— Other Genera— The Common British Tope— THE HAMMER-HEADED SHARK— THE SMOOTH HOUND— The Porbeagle, or the Beaumaris Shark— THE THRESHER, OR Fox SHARK— THE BASKING SHARK— -Enormous Proportions - The "Sea Serpent "—Habits- Fisheries— Characters THE SIX-GILLED SHARK THE DOG FISHES - The Nurse Hound and the Rough Hound Their Eggs and Egg-purses— ''Sea-dog Soup"— The Black-mouthed Dog-fish— Cestracion— THE PICKED DOG-FISH —Why so Named— Characters— Various Forms— THE SPINOUS SHARK— THE MONK-FISH— The Indian Shark Oil Industry— BATOIDEI, THE RAYS - Distinctive Features— THE PRISTID.E— THE RHINOBATIIXE— THE TORPEDI- NIDJE— THE GENUS TORPEDO— Strength of the Shock— The Electric Organs— Characters— Other Forms- THE RAYS -Characters -The True Skate— Fishery— THE LONG-NOSED SKATE— THE BORDERED RAY— THE SHAGREEN RAY —THE HOMELYN RAY— THE THORNBACK— THE STING RAYS— Growth of its "Spine"— Various Species— THE EAGLE RAY— THI Ox RAY, OR SEA DEVIL— CHONDROSTEI— THE STURGEONS— Characters - Caviare— Fishery —Other Economic Uses— The Common Sturgeon— Article of Diet- The Acipenser huso— The Sterlet . . 18

CHAPTER III.

THE PLECTOGNATHI. THE LOPHOBRANCHII. THE ANACANTHINI.

THE PLECTOGNATHI— Singular Shapes of the Fishes of this Order— Their Characters— The Triacanthinse— The Balistime— The File -fish— The Monacanthinse— The Ostracion— The Gymnodontes— The Genus Triodon— The Globe -fishes— The Genus Xenopterus— The Tetrodons— The Genus Diodon Darwin on the Habits of a Diodon Allied Genera— The Sun-fishes -The Common Sun-fish— Habits— Characters— The Oblong Sun-fish— THE LOPHOBRANCHII Their distinctive Features— The Solenostoma— Characters— The Syngnathidae Interest attaching to them— The Broad nosed Pipe-fish— Description— The Great Pipe-fish— Habits— The Marsupial Pouch Other Species The Ocean Pipe-fish The Worm Pipe-fish The Sea-horses Phyllopteryx Dr. Giinther's Account of its Spines and Filaments The Genus Hippocampus The British Sea-horse Other Species THE ANACANTHINI— THE COD-LIKE DIVISION— THE COD— Its Voracity— Its Fecundity— Tame Cod— Description of the Fish— The Cod-fisheries— Long-line and Hand-line Fishing— THE HADDOCK— A "Great Conchologist "— " St. Peter's Mark "—THE WHITING— Couch's Whiting-The Pollack —The Coal-fish— THE HAKE— The Greater Fork Beard— The Burbot— THE LING THE MACKEREL MIDGE— The Silvery Gade— The Rocklings— The Tadpole Hake -THE TORSK— The Ophidiidse— Characters— THE GENUS FIERASFER— Distinctive Features— The Greater Sand Eel— The Lesser Sand Eel— THE FLAT-FISH, OR PLEURONECTID.E— Characters -THE HOLIBUT— The Largest of the Flat-fish The Rough Dab, or Sand-sucker THE TURBOT THE BRILL THE WHIFF, OR MARY SOLE, OR SAIL-FLUKE— The Topknot— BLOCK'S TOPKNOT— The Scald fish, or Megrim, or Smooth Sole— The Genus Pleuronectes— THE PLAICE— Favourite Fish of the Poor— Lacepede's Story about Shrimps and Plaice— THE DAB, OR SALTIE, OR SALT-WATER FLUKE— The Smear Dab— The Pole, or Craig Fluke— THE FLOUNDER— THE SOLE —THE LEMON SOLE— THE VARIEGATED SOLE— The Solenette— Trawl Fishing 48

CHAPTER IV.

THE ORDERS PHARYNGOGNATHI AND ACANTHOPTERYGII.

Characters of the Order PHARYNGOGNATHI— THE POMACENTRID.E— Distribution— Diet— Distinctive Features— THE LABRID.E— Characters— The Ballan Wrasse— The Cook Wrasse— The Corkwing— Other Genera— The Group Chseropina— The Group Julidina— The Rainbow Wrasse— The Genus Pseudodax— The Group Scarina— The Group Odacina— THE EMBIOTOCID.E— THE GERRID.E— THE CHROMIDES— The Order ACANTHOPTERYGII— Dr. Giinther's Classification— THE PERCIDJE— The Perch— Where Found— Diet— Large-sized Specimens— Characters— The Bass— The Ruffe— Allied Genera— The Smooth Serranus— The Dusky Perch— The Stone Bass, or Wreck-fish —Why so Called— THE PRISTIPOMATID.E— THE SQUAMIPINNES— Characters— Various Genera— Curious Habit of Shooting at Insects— THE NANDID^E— THE MULLID.E— THE RED MULLET— Epicurean Luxury— Mode of Cooking —THE SPARID.E— THE BLACK SEA BREAM, OR OLD WIFE— The Bogue— The Common Sea Bream- The rilthead— THE HOPLOGNATHID.E— THE CIRRHITID^;— SCORPJENINA— THE POLYCENTRID.E— THE TEUTHIDID.E— THE BERYCID.E— THE KURTID.E— THE POLYNTMID.E— THE SCI^ENID^;— The Maigre— Value of its Head— THE XIPHIIDJE— The Common Sword-fish— Contests between Fox Sharks, Sword-fishes, and Whale— The " Sword "— THE TRICHIUEHXE— The Scabbard -fish— The Silvery Hairtail— THE ACRONURID.E— THE CARANGHXE— The Scad, or Horse Mackerel— THE CYTTINA— The John Dory— Characters— Whately's Little Joke— Legends about the Dory— THE STROMATEINA— THE CORYPII.ENINA— The Ray's Bream— The Opah— THE NOMEINA— THE SCOMBRINA —THE MACKEREL— Young " Shiners "—Size— Abundance— Migrations— Voracity— Mackerel-fishing— The Spanish Mackerel— The Tunny— Characters— Size— The Tunny Harvest— Beef-like Flesh— The Bonito— The Germon— The Genus Pelamys— The Genus Auxis— The Pilot-fish— THE SUCKING-FISH, OR REMOHA— Nature of the Sucking Disc . 74

265341

iv NATURAL HISTORY.

CHAPTER V.

ORDEH ACANTHOPTERYGII (concluded). PAGT

THE TRACHINID.E— Uranoscopus— Star-gazers The Greater Weever, or Sea Cat The Lesser Weever THE MALACAN- THID.E THE BATRACHID.E THE PEDICULATI THE SEA DEVIL, OR ANGLER Its Voracity The Genus Malthe COTTINA— THE MILLER'S THUMB, OR RIVER BULLHEAD— THE SEA SCORPION, OR FATHER LASHER— The Gurnards— THE CATAPHRACTI— THE COMEPHORID.E— THE DISCOBOLI— The Lump-sucker, or Lump-fish— The Sea- Snail THE GOBIID.E THE OXUDERCID.E THE CEPOLID.E THE TRICHONOTID/E— THE HETEROLEPIDINA— THE BLENNIID.E— The Wolf-fish, or Cat-fish— The Butterfly Blenny— The Shanny— The Viviparous Blenny— THE

ACANTHOCLINID.E— THE MASTACEMBELIDjE— THE SPHYRjENID.fi— THE ATHERINIDjE The Sand Smelt— THE

MTOILID.E The Grey Mullet THE GASTEROSTEID.E STICKLEBACKS The Three-spined Stickleback Its Pugnacity The Nest— The Ten-spined Stickleback The Nest The Fifteen-spined Stickleback, or Sea Adder The Nest— THE FISTULARID^:, OR PIPE-FISHES— THE CENTRISCID.E— The Trumpet-fish, or Bellows-fish— THE GOBIESOCIU.E— THE PSYCHROLUTID.E THE OPHIOCEPHALID.« The Walking-fish THE LABYRINTHICI Supra- branchial Organ— The Climbing Perch— THE LuciocEPHALiD.E— THE APHREDODERID.E— THE LOPHOTID.E— THE TRACK YPTERID.E— THE NOTACANTHI . 92

CHAPTER VI.

THE ORDER FHY8OSTOMI.

ORDER PHYSOSTOMI-SILURID.E— Characters— The Various Sub-Families— The Silurus Glanis-The Malapterurus electricus Its Electric Organ— The Genus Loricaria Curious Feature connected with the Genus Aspredo - CHARACINID*— HAPLOCHITONID^; STERNOPTYCHID.E Pearl-spotted Fishes— SCOPELUXE— Bombay Duck— STO- MIATID^ SALMONID.E— Characters— THE SALMON Description Climbing the Rivers The "Leaps" Changed Appearance after Spawning Hatching The Fry Growth-Stages of the Young— The Journey to the Sea The Salmon at Sea— Various Modes of Fishing Largest Catches Distribution THE GREY TROUT THE SALMON TROUT— THE COMMON TROUT THE GREAT LAKE TROUT Other Species of Trout THE CHARR Various Species THE SMELT THE CAPELAN The Genus Coregonus— THE POLLAN THE GRAYLING— PERCOPSID.E GALAXID.E MORMYRID.E— GYMNARCHID.E— EsqciDjE— THE PIKE— Its Size and Age— Its Voracity— Pike Migrations— The Lucie Family Characters of the Fish UMBRID.E SCOMBRESOCID<E The Genus Belone —The Garfish The Genus Scombresox The Saury, or Skipper The Genus Hemirhamphus The Flying Fish The Genus Exoccetus Characters Height and Duration of Flight C YPRINODONTID.E —Singular Eye Character of Anableps HETEROPYGII CYPRINID.E— Distinctive Features— The Carp— Habits— Carp Culture -Its Diet— The Crucian Carp— THE GOLD FISH— Kept as a Pet— Variation in Colour— Characters— The Barbel— The Gudgeon— The Roach— The Chub The Dace— The Ide— The Red-eye, or Rudd— The Minnow— The Red-fin— The Spawn-eater— The Tench— The Rhodeus amarus The Bream— The Bleak— The "Essence de 1'Orient " The Loach The Spinous Loach . . 107

CHAPTER VII.

PHYSOSTOMI (concluded) CYCLOSTOMATA LEPTOCARDII.

GONORHYNCHID^;— HYODONTID.E— OSTEOGLOSSID^E-CLUPEID^E— THE ANCHOVY— THE HERRING— The Fisheries— The Boat and Nets— The Whitebait— The Sprat— The Shad— The Pilchard— The Pilchard Fishery— CHIROCENTHID^E ALEPOCEPHALID.E— NOTOPTERID.E— HALOSAURID.E— GYMNOTID.E— The Electric Eel— Electric Organ— Effects of the Shock— SYMBRANCHID^E--MUR/ENID.E Characters— Various Types THE SHARP-NOSED EEL Weight Habits THE BROAD-NOSED EEL THE CONGER EEL— Characters Prehensile Power of its Tail Habits The Genus Muraena— PEGASID.E— CYCLOSTOMATA— Characters— MARSIPOBRANCHII— PETROMYZONTIDA:— Characters— THE SEA LAMPREY Distinctive Features Great Suctorial Power— Distribution— THE LAMPERN, OR RIVER LAMPREY— THE SAND-PIPER— MYXINID^E— Characters— THE HAG —Distinctive Features— Remarkable Nostril Character —Its Enormous Mucous Secretion LEPTOCARDII CIRROSTOMI THE LANCELET Size Characters Peculiar Heart and Blood —Difficulty connected with it and Hag— FOSSIL FISHES 134

THE ANIMALS WITHOUT BACKBONES— THE INVERTEBRATA.

INTRODUCTION.

Characteristics of Vertebrata Modifications Characteristics of the Invertebrata Various Distinctions among Them- selves—Habits— Classification Intermediate Groups 150

INVERTEBRATA.— TYPE MOLLUSCA. CHAPTER I.

THE CEPHALOPODA.

Cephalopoda Derivation of the Term Unexpected Relationships Shells Utility of Aquaria General Characters of the "Naked" Cephalopods— Classification : the Dibranchiata and Tetrabranchiata Their Mode of Locomotion The Mouth and Eyes Means of Escape and Defence— Representative Dibranchiates in the Ancient World DIBRANCHIATA, OCTOPODA— ARGONAUTID.E— The Argonaut, or Paper Nautilus— Its Fabled Position— Its Praises as Sung by the Poets How the Nautilus really Swims— The True Uses of the Arms Curious Fact regai-ding the Shell The Male as Compared with the Female The " Hectocotylus " Species of Argonaut— OCTOPODID.E The Common Octopus Appearance Formidable Seizing Organs Owen's Description of the Tentacles Mechanism of the Suckers The Octopods of Leghorn The Octopus of the Greeks Mr. Darwin's Account of the Octopus A Diver Attacked The Adventures of an Octopus in an Aquarium Spawning Season Eggs of the Octopus Henry Lee's Observations as to the Hatching of the Eggs The Baby Octopus New Growth of Amputated Limbs Food for Predatory Fishes Contests with the Conger Eel The " Devil-fish " and Nursehound Various Species of Octopus De Montfort's Gigantic Octopus Cuttles and Octopus as Diet —Octopus Fishery— DECAPODA— TEUTHID^E— Distinctive Features— The Tentacles— Suckers— Shell— Remark- able Skin Characters— Play of Colours THE COMMON SQUID— "Pen-and-ink Fish " Their Spawn The "Little Squids" The Nerve-masses of the Dibranchiata A Tom Thumb Cephalopod Loli<iopsis Ckeirotcuthis Histioteuthis The Clawed Calamary Construction of the Suckers of the Calamary The Armed Calamary The Sagittated Calamary " Sea-arrows " Squid-bait The Cod-fishery Squid-jigging The Giant Cephalopods —Instances of their being Met with, and of their Capture Sir Francis Chantrey and Fossil Ink BELEMNITHXE No Living Representative What the Fossil really is Species SEPIAD.E— The Common Cuttle-fish— Beautiful Coloration The Bone or Shell The Cranial Cartilage in the Cuttle The Heart Movements in the Water

CONTENTS. v

PAGE

Not Long-lived in Confinement, and why— The Cuttle's Eye— The " Ink-bag "—Discharge of the Ink— Use of the Ink The Eggs of the Cuttle Young Cuttles Uses of the "Bone" Various Species of Sepia The Cuttle as an Article of Diet SPIRULID,E Genus Spirula— Remarkable Characters Rarity Difficulty of Studying it Peculiar Shell Characters— ORDER TETRABRANCHIATA— NAUTILIAD/E— External- shelled Cephalopods— Nautilus and Spirula the only Siphonated Shells Living Construction of the Shell Rumphius's Account of the Pearly Nautilus— Mr. Moseley's Observations How the Animal Moves Abundance Various Parts of the Nautilus The Air-chambers The Uses of the Siphuncle Formation of the Septa Fossil Members of the Tetrabranchiata 154

CHAPTER II.

THE GASTEROPODA.

'Shell-fish" Uses of the Shell The Kinds of Shells Economical Uses of the Mollusca in the Earliest Period and in the Present Day— Form and Growth of Shells Parts of a Shell— Order I. PROSOBRANCHIATA : (a) SIPHONOSTOMAT A— Siphonated Gasteropoda— Family I. STROMBID^:, " Wing-shells "—2. MURICID.E— Murex, the Source of the Celebrated " Tynan Purple " Dye " Mitre-shells " Fusus, the " Red Whelk " Whelks used for Food Hemifusus, one of the Largest of Living Shells «t. BUCCINID.S Buccinum, "Triton's Shells "- The "Dog Whelk," Nassa Purpura Its Dye How it Tackles its Prey Magilus Boring in Coral— The Harp- shells The Olives— 4. CASSIDID^E Cassis "Cameo-shells" Triton Use of the Sheilas a Trumpet Growth of Sea Snails— 5. CONID.E The " Cones" Their Beauty and Commercial Value Conus Gloria-maris Terebra, the " Auger-shell "—6. VOLUTID.E Rarity of the Volutes 7. The CYPRJEUXE Cowries Richness of their Colour and their Value Past and Present Prices of Specimens of Rare Shells The Money Cowry— Cuttle-fishing with Cowry Bait— Shells as Articles of Ornament in Dress— Ovulum 189

CHAPTEE III.

THE GASTEROPODA (concluded) AND PTEROPODA.

Order I. (concluded)— (b) the Holostomata, or Entire-mouthed Sea Snails— Family 8. NATICIOE— 9. CANCELLARIAD.E— 10. PYRAMIDELLID.E— 11. SOLARIAD.E— "The Staircase-Shell "—12. SCALARIAD.E— Scalaria pretiosa, the "Wentle- trap" Great Value attached to this Shell 13. CERITHIAD,E Potamides in Fresh Water 14. TURRITELLID-E "Tower-shells" Vermetus Worm-shells 15. MELANIAD^E— 16. PALUDINID.E Fresh-water Snails the "Apple Snail," Ampullaria Its Tenacity of Life 17. LITTORINID.E— Periwinkles as Food 18. CALYPTRA:IIXE "Bonnet Limpets" The Grotto-shells, Phorus 19. TURBINID.E— Trochus 20. HALIOTID-E The Ear-shell, Haliotis Uses of Pearly Shells Pleurotomaria —Its Rarity 21. IANTHINID^E lanthina, "Floating Shells" The Raft 22. FISSURELLID.E 23. NERITID.E— 24. PATELLID.E— "Limpets" Used as Food How the Oyster-catcher Detaches them— 25. DENTALIAD.E— 26. CHITONID.E— Multivalve Snails— Order II.. PULMONIFERA— Air-breathers- Anatomy of a Snail Inoperculata, or Land Snails without Operculum— Characters Curious Experience of a Desert Snail— 27. HELICID.E— Used as Food— The Largest Land Shell Known— The Odontophore, or Tooth-bearing Tongue—Other Genera— 28. LIMACID.E The Slugs— The Mucus Secretion and its Uses 29. ONCIDIAD.E 30. LIMX.EID.E Air-breathing Pond Snails— 31. AuRicuLiDJi— Operculata, or Operculated Land Snails 32. CYCLOSTO- MID.E 33. HEUCINID.E 34. ACICULID.E Order III., OPISTHOBRANCHIATA 35. TORNATELLID.E— 36. BI-LLID,E 37. APLYSIAD.E "Sea Hares" 38. PLEUROBRANCHID.E— 39. PHYLLIDID^E The "Sea Slugs" 40. DORID,E 41. TRITONIAD.E 42. ^EOLIDJE 43. PHYLLIRHOID.E 44. ELYSIAD^E Order IV., NUCLEO- BRANCHIATA— Oceanic Snails-45. FiROLiD^E— The Carinaria— 46. ATLANTIIXE— Class III., PTEROPODA Their Pelagic Character Their Abundance Source of Food to the Right Whale Their Wing-feet compared to Moths— Delicacy of their Shells Distribution 207

CHAPTEE IV.

THE CONCHIFERA.

Class IV., CONCHIFERA Bivalve Shells— Their Sedentary or Burrowing Habits— Structure of Bivalve Shells- Anatomy of Animal— Muscles, Mantle, Gills, &c.— Family 1. OSTREID.E— Oysters— Their Economic Value Frank Buckland on the Oyster —The " Points " of an Oyster— Mode of Cultivation— The Young Oysters— Their Enemies— Their Sensitiveness to Cold— Ancient Shell Relics— 2. ANOMIAD^E— 3. PECTINID^E- Scallop Shells— The St. James's Shell The Spondylus, or Thorny Oyster Vivacity of Young Pecten Value of Bivalve Shells— 4. AVICULID.E— Pearl Oysters— Use of Shells— Value of Pearls— Pearl-fishery, Ceylon— The Divers— THE GREAT PINNA 5. MYTILID.E Mussels A Bridge Preserved by Mussels from Destruction Boring Shells, Lithodomi -6. ARCADE 7. TRIGONIAD.E Trigonias 8. UNIONHXE River Mussels Pearl Mussels— 9. CHAMID.E 10. TRIDACNID.E Giant Clams 11. CARDIAD.E 12. LUCINID.E 13. CYCLADID.E 14. ASTARTIDJS 15.

CYPRINIDjE 16. VENERIDJ2 17. MACTRID.E 18. TELLINID.E— 19. SOLENID.E " Razor-shells " 20. MYACID.*

21. ANATINHXE 22. GASTROCH^ENID.E Stone-borers 23. PHOLADID*— Wood-borers The Ship-worm . . 230

INVERTEBRATA.— INTERMEDIATE TYPE. THE TUNICATA.

Structure of the Tunicata Explained The Throat or Gullet serving as the Breathing Organ Curious Ebb and Flow of the Blood Their Division into Simple, Social, and Compound Ascidians Known to Aristotle 1. SIMPLE ASCIDIANS Muscular Nature of Tunic "Sea-Squirts" Where Found— 2. SOCIAL ASCIDIANS Mode of Union Genera— 3. TRUE COMPOUND ASCIDIANS Their Anatomy 4. THE PYROSOMID^E Their Pelagic Habits Their Phosphorescence 5. SALPID.E— Pelagic— Solitary or in Chains 252

THE INTERMEDIATE GROUP, MOLLUSCOIDA.

THE MANTLE-BREATHING BIVALVES (BRACHIOPODA) AND THE MOSS ANIMALS (BRYOZOA).

THE BRACHIOPODA— Life History and Characters of the Brachiopoda— Origin of the Name— Subdivision "of the Group— Its Relations to other Organisms— Growth and Structure of the External and Internal Skeleton Muscles Organ of Attachment Mantle— Gills Digestive, Generative, and Nervous Systems— How the Brachiopoda Live —Classification and Anatomy of Minor Groups Distribution in Space and Ranges of Depth of Living Forms— Fossil Genera— Embryology and Affinities— THE BRYOZOA— Life History of the Moss-animals —Name and Position of the Group— Its Chief Subdivisions— The Colonial Skeleton— The Individual Moss-animal Muscles and their Action Respiratory, Circulatory, and Reproductive Systems Structure and Functions of the Appendicular Organs— Classification and Anatomy of Minor Groups Geographical and Bathymetrical Dis- tribution of Marine and Fresh-water Genera Geological Range Reproduction of the Colony and of the Individual Embryological History— Affinities and Systematic Position of the Brachiopoda and Bryozoa . . . 2-58

vi NATURAL HISTORY.

CLASS INSECTA. CHAPTER I.

ANATOMY OF INSECTS. PAGE

Characteristics of the Arthropoda— Insects— Divisions of the Body— Segments of the Abdomen— Structure of the Thorax —The Jointed Limbs— Parts of the Leg— The Feet— The Wings— The Head— The Antennae— The Organs of the Mouth— Segmentation of the Head— Modifications of the Mouth in Sucking Insects -The " Moulting "- The "Transformations " of Insects : Larva, Pupa, and Winged Stages— Internal Anatomy— The Nervous System Structure of the Eye— Function of the Antennae -The Digestive System The Circulatory Apparatus How Respiration is Performed— Reproduction— Classification 281

CHAPTER II.

ORDER COLEOPTEKA : CARNIVOROUS BEETLES.

Definition of the Order Functions of the Coleoptera in Nature Total Number of Existing Species External Structure Metamorphosis and Early Stages Instincts Voice-organs and Organs of Hearing Hidden Nature of the Haunts of the Majority of the Species of Coleoptera Nocturnal Habits Attracted by Light— The Number and Variety of Specie s swept down by Floods in River-valleys— Fossil Beetles— Section PENTAMERA, Beetles with Five-jointed Tarsi Tribe ADEPHAGA, or Predaceous Beetles Family CiCLNDELiD^E, or Tiger Beetles —Family CARABID^:, Carnivorous Ground Beetles 296

CHAPTER III.

CARNIVOROUS, ANOMALOUS, AND BURYING-BEETLES.

PENTAMERA (continued] Family DYTICID.S, or Carnivorous Water - Beetles Air-breathing Insects Peculiar Mode of Respiration Structure, Transformations, and Habits— Family GYRINID^S, or Whirligig Beetles Curious Mode of Progression on the Surface of the Water explained Family PAUSSID.E— Grotesque Forms— Kept as Involuntary Guests of Ants Tribe PALPICORNIA Family HYDROPHILIIXE, Herbivorous Water-Beetles— Carnivorous Habits of the Larvae Families GEORRYSSID^:, PARNID.E, and HETEKOCERID.E Mode of Breathing by Air-bubbles carried beneath the Water by the Parni Tribe BRACHELYTRA : Family STAPHYLINID.E— Low Type of Structure Families PSELAPHID.E and ScTDMJfSTDJt Blind Pselaphidse, the Pets of Ants— Tribe NECROPHAGA or CLAVICORNIA Heterogeneous Composition of the Tribe— Family SILPHID.E— Burying Beetles, and their Singular Habits— Families TRICHOPTERYGID.E, SCAPHIDIID.E, PHALACRID.E, and NITIDULID.E— The Smallest Beetles known Families TROGOSITID.E to HISTERID.E— End of the Necrophaga 309

CHAPTER IV.

THE LAMELLICORN AND SERRICORN BEETLES.

PENTAMERA (continued) TRIBE LAMELLICORNIA— High Degree of Specialisation of the Tribe— Concentration of the Nervous System Larvae and Metamorphosis Horned Species FAMILY LUCANID^E, or STAG BEETLES FAMILY SOAJURSmz, or TRUE LAMELLICORNIA— Dung-feeding Scarabaeidse— The Sacred Beetle— Pill-rolling— A Parasitic Species Burrows of Geotrupes Leaf -eating Scarabaeidas— Cockchafers Goldsmith Beetles Rhinoceros and Elephant Beetles— Rosechafers —Goliath Beetles TRIBE SERRICORNIA Peculiar Structure of the Fore and Middle Sternums— FAMILY BUPRESTID.E— FAMILY ELATERID.E, or CLICK BEETLES— Fireflies— TRIBE MALACODER- MATA— Glowworms— Object and Cause of their Light— FAMILIES CLERHXE, PTINID^:, AND BOSTRICHIDJE . . 322

CHAPTER V.

SECTIONS HETEROMERA, TETRAMEUA, AND TRIMERA.

SECTION HETEROMERA : Beetles with Five-jointed Tarsi to the Four Anterior, and Four-jointed to the Two Posterior Legs Division of the Heteromera into Atrachelia and Trachelia Habits Churchyard Beetles— Blister Beetles Hypermetamorphosis Singular Parasitic Habits and Mode of Development of Sitaris, Meloe, Cantharis, Rhipiphorus, Hornia, Rhipidius, and the Stylopidce SECTION TETRAMERA: Beetles with Four- jointed Tarsi Family CURCULIONID.E, or Weevils— Family SCOLYTID^E, or Bark Beetles Habits of some of the British Species -Families BRENTHID^;, ANTHRIBID.E, and BRUCHID.E (Seed-borers)— Tribe LONGICORNIA— Great Beauty and Variety of Form and Colours Night-flying and Day-flying Longicornia Musk Beetles Gigantic Species Mimetic Resemblances and Protective Disguises— Branch-sawyers— Popular Errors on the Subject Tribe PHYTOPHAGA, or Leaf-eaters Strange Habits of some of their Larvae Tribe EROTYLIDES SECTION TRIMEHA : Beetles with Three-jointed Tarsi— Lady-birds 336

CHAPTER VI.

ORDER HYMENOPTERA : ACULEATA, Oil STINGING HYMENOPTERA.

Characters— The Prpthorax— The Membranous Wings— The Ovipositor, or " Sting "—Internal Structure— Habits- Larvae— Intelligence of the Hymenoptera Their Social Organisation Workers, or " Neuters "—The Sexes— The Humming of the Bee— Species of Hymenoptera— Fossil Remains -Classification— ACULEATA, OR STINGING HYMENOPTERA— APIARLE, or BEES— Characters— THE HIVE BEE— The " Hive "—Arrangement of Cells- Intelligence evinced by the Bees— The Secretion of Wax— Construction of the Cello— Deposition of Eggs- Transformations of the Bee— The Workers— Bees in Winter- The " Royal " Cell— Swarming— Formation of a New Hive— Behaviour of the Young Queen— The Cases of Limited Fertility— HUMBLE BEES— Habits— Apath us vestalis—The Solitary Bees— THE VIOLET CARPENTER BEE- -Gnawing-out and Excavation of the Nest— THE MASOV BEE— Its Cell— The Genus Osmia— The Leaf-cutting Bees— The Cuckoo Bees— The Andrenidce— VESPID.E, OR WASPS - Characters - Cells— Beauty of Workmanship— Mr. F. Smith's Account of the Founders of a Wasp Colony— Nests of the Common Wasp and of the Hornet— The Nests of other Species— The Solitary Wasps The Wall Wasp— THE CRABRONID.E -The Sand Wasps— THE POMPILHXE - THE SAPYGID.E— THE MCTILLIM— THE FORMICID^;, OR ANTS— Characters— The Nests— The Metamorphosis -The Workers— Milking the Aphides- Charge of the Young— Habits— Intelligence— The Wood Ant— Other Species— THE CHRYSIDID^:, OR GOLDEN WASPS . 353

LIST OF rLLTTST RATIO ITS.

The Blue Shark Frontispiece

The Common Pike 1

Skeleton of the Common Perch 3

Skull of Codfish 5

Scales of Fish

Diagram of Brain of Codfish 10

Jaws of Male and of Female Skate . . . .12

Internal Anatomy of the Carp 13

Swimming Bladder of Carp 14

The African Mud-fish 19

The Ceratodus 21

The Polypterus 22

A Vertebra of the American Bony Pike . . .23

Chimaera Colliei 24

Diagram of Brain of Skate ...... 25

The Hammer-headed Shark 28

The Smooth Hound 29

The Nurse Hound 32

Egg Purse of Nurse Hound J

Egg of Cestracion ; Section of the same . . .33

The Picked Dog-fish 34

The Monk-fish 36

The Torpedo Marmorata .39

TheThornback 42

The Common Sturgeon 45

Ostracion quadricornis ....... 49

Tetrodon fahaka (Floating Belly upward) . . .50

The Broad-nosed Pipe-fish 54

The Phyllopteryx 57

The Whiting 61

The Lesser Sand Eel 66

The Turbot 68

The Plaice 70

The Rainbow Wrasse 76

The Epibulus Insidiator 77

The River Perch 78

The Bass 79

The Toxotes To face page 81

The Pelor filamentosum 82

The Maigre . 84

The Common Sword-fish . . .To face page 85

The Flying Sword-fish 85

The John Dory 87

TheOpah 88

The Pilot-fish 90

The Sucking-fish, or Remora 91

The Uranoscopiis Scaber 93

The Malthe Vespertilio 94

The Sea Scorpion 95

The Armed or Mailed Gurnard 97

The Butterfly Blenny 99

The Ten-spined Sticklebacks 101

The Fifteen-spined Stickleback 102

The Trumpet-fish, or Bellows-fish ....'. 104

The Climbing Perch 105

Supra-branchial Organ of the Climbing Perch . . 106

Malapterurus electricus 109

Loricaria cataphracta 110

The Salmon 113

The Common Trout . . .To face page 117

. 118

The Smelt .

The Grayling

The Garfish .

The Exocoetus volitans

The Crucian Carp .

119 122 123 126

The Roach 129

The Tench 131

Rhodeus amarus 132

Vertebra of Herring 135

The Herring 136

The Sprat .137

The Conger Eel 142

PAGE

The Pegasus Draconis . .... 144

The Sea Lamprey . . .... 144

The River Lamprey . .... 145

The Lancelot . . . .... 147

Tongue of the Octopus . .... 155

Fabled Position of the Paper Nautilus . . . .150

The Paper Nautilus and the Octopus . To face page 157 Argonaut as it Swims Backward (Natural Position) . 157

Paper Nautilus in its Shell 157

Cross Section of Arm of Octopus Suckers of Octopus . 158 The Common Octopus ....... 159

Octopus horridus— Octopus macropus . . . . 1 60

The Common Octopus . . . .To face parie 161

The Octopus Reposing 162

The Pinnoctopus— Cirroteuthis Mulleri . . . 164

The Common Squid 167

Buccal Aspect of Common Squid Loligopsis . . 168

The Pen of the Calamary 169

Gigantic Cuttle-fish Hooked off Teneritfe . . .172 Upper and Lower Jaw of Architeuthis monachus . . 173 Marginal Ring of Sucker from one of the Sessile Arms of Architeuthis monachus. Large and Small Sucker from the Tentacular Arms of Same. Larger Sucker from Tentacle of Same .... 173

Belemnite Restored 175

The Common Cuttle 176

Branchiae and Hearts of Common Cuttle . . . 177

Sepia elegans 178

Eggs of the Common Cuttle-fish— Shell of the Sepia . 180

Section of Spirula Australis 181

Spirula Australis 182

Interior of the Shell of the Pearly Nautilus . . . 185 Exterior of the Shell of the Pearly Nautilus . . 186 Section of the Shell of the Pearly Nautilus . . .186

Shell of Triton 191

Strombus gigas, with the Animal Pteroceras lambis . 192 Murex tenuispina Mitra episcopalis .... 193

Fusus proboscidalis 194

A Group of Sea Snails Patella vulgata ; Buccinum undatum ; Nassa reticulata ; Haliotis tuberculata ;

Littorina littorea 196

Purpura lapillus Purpura patula .... 197 Magilus aritiquus Harpa imperialis Harpa articularis 198 Oliva erythrostoma Oliva porphyria .... 199 Cassis canaliculatus Cassis madagascariensis . . 199 Triton variegatum . .... 200

Cones and Volutes . To face page 201

Terebra tigrina .... 201

The Cowry (Cyprsea tigris) and its Animal . . . 203 The Money Cowry . .... 204

Cowries ... .... 205

Ovuluni volva 206

Natica papilionis 207

Solarium perspectivum Scalaria pretiosa Cerithium

aluco 209

Turritella terrebellata Vermetus lumbricalis . . 210 Melania amarula Lingual Teeth of Ampullaria—

Ampullaria canaliculata 211

Phorus conchyliophorus Turbo argyrostomus Turbo

imperialis . . 214

Trochus niloticus Trochus virgatus Haliotis tri-

costalis 215

Pleurotomaria quoyana Pleurotomaria platyspira . 216 lanthina communis lanthina and its Raft . . . 217 Dentalium elephantinum— Chiton magnificus . . 219 Anatomy of the Common Garden Snail . . . 220

Land Snails To face page 221

Helix pomatia 221

Lingual Teeth of Achatina fulica .... 222

A Slug. (Arion ater, " Black Arion") .... 223 Lingual Teeth of Testacella haliotides .... 223 Limnsea stagnalis Physa castanea . 224

NATURAL HISTORY.

PAGE

Cyclophorus, an Operculated Land Snail . . . 225 Bulla oblonga— Aplysia inca Shell of Aplysia inca . 225 Idalia ; Miranda ; Dendronptus ; Doto ; Hermsea ;

Glaucus Carinaria cymbium .... 227 Hyalea gibbosa Hyalea longirostris Cleodora cuspi- data C. lanceolata C. compressa . . . 229

Anatomy of a Common Oyster 231

Anatomy of Cytherea . 232

Young Oysters furnished with Locomotive Organs . 234 Group of Oysters of Different Ages . . . .234 Shells of Pecten and Spondylus . . To face page 265

Meleagrina margaritifera 237

The " Hammer Oyster " 238

Pinna nobilis, with its Byssus The Sea Mussel . . 239 Three Erect Columns of the Temple of Serapis at

Puteoli bored by Lithodpmi 240

Anatomy of Trigonia pectinata Trigonia costata

Trigonia pectinata 241

Unio pictorum Anodonta ensiformis .... 242

Tridacna squamosa ....... 243

Cardium edule ; Cardium echinatum ; Mya arenaria ; Cytherea chione ....... 244

Venus verrucosa, with its Animal Cytherea geogra- phica, with its Animal Cytherea maculata . . 246

Tellina radiata 247

Donax trunculus Solen ensis Solen vagina . . 248 Anatomy of Soft Parts of Mya arenaria . . . 249

The Watering-pot Shell 250

Pholas dactylus in a Shelter— Teredo navalis . . 251

Structure of Tunicate 252

Cynthia (Ascidia) microcosmus 253

Boltenia (Ascidia) pedunculata ..... 254 Pyrosoma . . . . . . . . . 256

Salpa maxima 257

Terebratula cubensis Discinisca lamellosa . . . 258 Rhynchonella spinosa ; Productus longispinus ; Cho- netes ; Ventral Valve of Productus complectens . 259

Sections of Shell Structure 260

Ventral and Dorsal Valve of "VValdheimia australis . 261 Ventral and Dorsal Valve of Lingula anatina . . 261 Dingula pyramidata ....... 262

Animal of Lingula anatina ...... 263

Crania anomala ........ 264

Internal cast of Dorsal Valve of Orthis ; Section of Pentamerus, showing Chambers Dorsal Valve of Spirifera glabra ; Dorsal Valve of Rhynchonella psittacea ......... 265

Loop of Liothyris ; Terebratulina ; Terebratella ; Bou-

chardia ; Megerlia ; Argiope 266

Thecidium Mediterraneum, as in Life . 266

Terebratula Wyvillii 267

Free- swimming Ciliated Larva of Terebratulina ; At- tached ; Later Stage ; Horse -shoe stage of Loop . 268 Bugula purpurotincta ....... 269

Cristatella mucedp 270

Winged, Crescentic, and Circular Type of Gill Tentacles 271 Alcyonidium gelatinosum ; Plumatella allmani . . 272 Cell and Anatomy of a Moss-animal .... 272 Moss-animal Retracted in its Cell .... 273 Communication Plates and Pores in Cell Walls of Membranipora msmbranacea ; Perforated Stem of Zoobotryon Alimentary Canal of Cellepora. . 274 Cells of Cheilostomatous Bryzoon Portion of Poly- zoarium with Vibraculee ; Sessile and Pedunculate Avicularia Cells of Bugula avicularia, with Avi-

cularia holding a Worm 275

Stomatopora dichotoma ...... 276

Bowerbankia Endoproctous Type, Pedicellina cernua 277 Free-swimming Ciliated Cheilostome Larva ; Statoblast

of Fredericella . 280

A Beetle with the Head, the Portions of the Thorax,

and the Abdomen Separated and Magnified . . 281 Side View of Abdomen of Decticus .... 282

Walking Leg of Cockroach 283

Head of Hornet Various Forms of Antennae . . 284

Organs of the Mouth 285

Earwig in its Development 288

Larva, Chrysalis, and Imago of Papilio machaon. . 289 Nervous System of Larva of Bee ..... 290 Nervous System of Perfect Bee ..... 291

Structure of Eye of Cockchafer 292

Digestive Apparatus of Dyticus 293

Cpleoptera Escaping from a River-flood . . . 301

Cicindela campestris and Larvze 302

Phseoxantha klugii 303

Carabus auratus ........ 304

Carabus adonis ........ 305

Procerus gigas Damaster blapto'ides .... 306

Mormolyce phyllodes Tefflus megerlei. . . 307 Hyperion schrceteri Anthia thoracica .... 308

Dyticus marginalia ....... 310

Haliplus fulvus Laccophilus variegatus— Hydroporus

griseostriatus— Suphis cimicoides .... 311 Enhydrus sulcatus Gyrinus distinctus . . . 312

Hydrophilus piceus 313

Ocypus olens (Devil's Coach-horse) and Larva . . 315

Pselaphus heisii 310

The Burying-Beetle 318

Dermestes lardarius and D. vulpinus .... 321 Cerambyx heros and Lucanus cervus (The Stag

Beetle To face page 324

Dorcus titan 324

Sacred Beetle 325

Cockchafer 327

Xylotrupes dichotoma Megaoeras chorinseus . . 328 Megasoma typhon Goliathus druryi .... 329

Ceratorhinapolyphemus 330

Rosechafer Cyria imperialis 331

Chalcophora mariana— Elater preparing to Spring

Jumping Organ of Elater ..... 332

West Indian Firefly Alaus oculatus .... 333

Lampyris splendidula ....... 334

Meloe cicatricosus Sitaris muralis .... 337

Stylops spencei 339

Rhynchophorus palmarum ...... 341

Rhynchites bacchus— Apoderus coryli .... 342

Larinus maculosus 343

The Stag-horned Longicorn . . To face pac/e 345

Oncideres vomicosus ....... 347

Crioceris merdigera 349

Lina populi 350

Seven-spotted Lady-bird 351

The Tailed Wasp 353

Diagram of Hymenopterous Wing .... 354

Common Wasp— Larva of Saw-fly 355

Larva, Nymph, and Cocoon of Wood Ant . . . 356

Head of Bee— The Hive Bee 359

The Honeycomb Under Surface of Bee, showing the

Wax between the Segments 361

Apathus vestalis 366

Osmia leucomelana and its Nest . 368

Leaf-eating Bees and Nests . . .To face page 369

Mason Bee 369

Polistes gallica and Nest ...... 372

Philanthus triangulum and Nest 374

Pelopseus spirifex and Nest 375

Mutilla europsea 377

TheWoodAnt 378

Myrmecocystus mexicanus ...... 382

SaubaAnt 383

1. Pike (Esox Indus}.

2. Great Red Fire-fish tScorfana milesl. •5. Blue Crescent-tail (Afesotsionemeryii).

4. Leaf-moon Chaetodon (Chatodon vesfertilio).

5. Blue Shark (Carckariat glancus\.

FISHES.

6. Saw-fish (Pristis antiquorum).

7. Starry Ray (Raja radiata).

8. Ox Ray (Dicerobatis giom<e\.

9. Plaice (Pleuroncctex flatessa). 10. Trunk-fish (Ostracion fHadrict

i. Blue-striped Wrasse (Labrtti > •2. Mailed Gurnard (Peristelhus

turn).

iixtus\. cataphrac

13. Muracna (Murana kelena).

CASSELL'S NATURAL HISTORY.

COMMON PIKE.

CLASS PISCES.— FISHES.

CHAPTER I. GENEKAL INTRODUCTION.— THE ANATOMY AND OTHER CHARACTERISTICS OF FISHES.

Immense Vaiiety of Forms Charactenstics of the Class Industrial Importance to Man Fecundity Colour— Mental Endowments— Their General Structure The Lowest Type of Fish Structural Features in Sharks and Rays— The Skull Peculiarities in the Lepidosiren— Skull of Codfish The Sense Capsules Teeth and Jaws— The Branchial Arches— The Muscles of Fishes— The Skin and Mucous System— To what Causes the Colour of Fishes is Due— The Scales of Fishes— Agassiz's Classification based on Scales— The Nervous System— The Spinal Cord— The Brain— Organs of Smell, Sight, and Hearing— The Electric Organs— The Teeth of Fishes— The Alimentary Canal— The Liver— The Air-bladder— The Blood— The Heart— The Gills— Fins and their Functions— Classification of the Fishes.

FISHES are the only primary division of the Vertebrata which live in water, and have no repre- sentatives passing their lives upon land or in the air. This condition of existence is probably the cause of the close correspondence in bodily form in the majority of fishes, which progress through the water chiefly by movements of the tail, and use the fins as organs with which to steer a path. Clear as is the idea which rises in the mind at the mention of a fish, the multitudes of forms which fishes exhibit are greater, perhaps, than those to be found in any of the preceding great 191

2 " NATURAL HISTORY.

groups of animals which have already been described. The slender form of the Lamprey or Eel contrasts with the expanded body of the Turbot or Plaice ; the short deep form of the Sun-fish is unlike the broad, flattened, and long-tailed Skate ; the Sea Horses, when attached by their prehensile tails, at first sight present none of the familiar characteristics of fishes ; the Flying-fish, which have the fins so expanded as to serve some of the purposes of wings, present a remarkable contrast to the spheroidal spiny body of the Globe-fish ; while the Hammer-headed Shark exhibits a form of body in some respects more singular still. When we turn to details of proportion and structure, and contrast the shapes of the head or of the tail, the variety among fishes is altogether exuberant. Ill the covering of the body there is not so much scope for variation, for although some are con- tained in a box of bony plates, or mailed with armour far heavier in proportion than that of the knights of old, and some fishes have, on the other hand, scales so delicate that they are detected with difficulty, yet by far the larger number of living fishes are clothed with soft scales, which impart to them much of their beauty, and differ in little more than size and details of ornament in the multitudinous genera. But beyond the claims upon our attention which the external forms of fishes certainly make, an interest of a far higher kind is always aroused by their wonderful habits. Here we find the herbivorous and carnivorous types of the land reproduced. Many fishes like the Sword-fish, for instance seem specially moulded into shape for purposes of slaughter: many fishes, like most of those with transversely-expanded bodies, pass their lives more or less quietly on the bottom of the sea, and simulate the sand they rest upon; other groups, like Eels, dive into the sand as though it were their natural home ; others, again, like the Gurnards, crawl with their appendages at the sides of the head, almost like some of the Crabs, when they are not freely swimming. Some fishes, like the Sturgeon, find their home indifferently in fresh or salt water ; several, like the Salmon, require to descend annually from the river to the sea. Multitudes of fishes travel in fellowship year by year over a large portion of the ocean, a few fresh-water fishes journey over land, and one or two are sometimes found roosting like birds in the branches of trees.

The industries which fishes have contributed to develop have given this group of animals an importance scarcely second to mammals and birds. No small proportion of the food of mankind is obtained by the fleets of fishing-boats around the coasts, and by the humbler nets, and snares, and lines with which fishes are captured in rivers and lakes. The use of fish for manure is of ancient date ; the capture of fishes for the manufacture of medicinal and other oils, gelatine, and isinglass is carried on on a large scale ; the skins of Sharks have always been valued for the decoration of some kinds of military weapons no less than by the cabinet-maker for their rasping properties. Much of the artificial jewellery, which resembles pearls so closely as almost to equal the natural production of the sea-shell Avicula margaritifera, owes its beauty to a preparation from the scales of the Bleak and other fishes.

The fecundity of fishes far surpasses that of any other group of vertebrated animals. The eggs laid by a single fish sometimes may be counted by millions. They are almost always small as may be seen in the ordinary hard roe of the fishes which are eaten and are frequently minute. They pass through no metamorphosis, as do the young in their development among the higher group named Amphibia ; but occasionally fishes are viviparous, and then the young are retained within the body of the parent until they have reached a relatively large size. Fishes furnish us with the smallest examples of the Vertebrates which are known, and also with some of -the biggest forms, though they never make any approach to the giant length of the larger Whales. By far the greater number of fishes are of relatively small size.

As with mammals and birds, the great majority of fishes are characterised by comparatively dull colours, which probably serve to conceal them from enemies, and have been developed as a means of enabling them to mimic the aspects of the regions of sea and river which they frequent. But all are not so simply decorated. The brilliant colours of the gold and silver and violet Carp are well known. Many fishes are striped and spotted, or burnished with colours which almost rival those of gaudy birds, and it would be difficult to name a tint which could not be matched among some representatives of the fish class. Too little, however, is known of the habits and ways of life of these highly-coloured fishes to enable us to judge how far they are an advantage to the species, which are thus characterised.