WeSt,.Newmaji chr.ad iiat.

TYPICAL BUTTERFLIES.

/ '

,li«inif)A ojwiaM .H .<t*U<

A. Orange Scallop Wing, Cethosia biblis (male). B. Royal Swallow Tail, Tinopalpus impcrialis (male). C. Black-tipped Sulphur,
Dercas verhuelli. D. Swinhoe's Tortoiseshell, Junonia swinhot i. E. Common Blue, Lyccena alexis (male). F. Mango Admiral,
Euthalia lubentina. G. Silver-studded Skipper, Hesperia comma. H. Sooty-veined Porcelain, Cyrestis thyodamas. I. Duke of
Burgundy, Nemeobius lucina, J. Harris's Snowfiake, Euplcea harrisii (female).

THE ROYAL

NATURAL HISTORY

f&m.

THE ROYAL
NATURAL HISTORY

EDITED BY

ARD LYDEKKER, B.A., F.R.S., Etc.

WITH PREFACE BY

P. L. SCLATER, M.A., Ph.D., F.R.S., ETC.

SECRETARY OF THE ZOOLOGICAL SOCIETY OF LONDON

ILLUSTRATED WITH

Seventy-two Coloured Plates and Sixteen Hundred Engravings

W. KUHNERT, F. SPECHT, P. J. SMIT, G. MUTZEL, A. T. ELWES, J. WOLF,
GAMBIER BOLTON, F.Z.S.; AND MANY OTHERS

VOL. VI.

LONDON"

FREDERICK WARNE & CO.

AND XEW YOKK

1896

[All Rights Reserved]

■

an

Lot
v. U

PRINTED BY MORRISON AND OIBB LIMITED, KDINBUROH

CONTENTS

INVERTEBRATE ANIMALS

CHAPTER I. — The Jointed Animals, — Subkingdom Arthropoda ; The Insects,-
Insecta ; Ants, Bees, Wasps, etc., — Order Hymenoptera.

-Class

Distinction between Vertebrates and Invertebrates — Special Characters of Arthropods
— Distinctive Characteristics of Insects — Geological Age of Insects — Other Features —
Mimicry — Characteristics of Hymenoptera — Development — Classification — The Saw-
Fly Group (Suborder Sessiliventres) — Stem Saw -Flies (Cephidce) — Tailed Wasps
(Siricidce) — True Saw-Flies (Tenthredinidai) — Typical Group (Suborder Petiolata) —
Gall-Wasps (Cynipidce) — Proctotrypidce — Chalcididce — Ic\mei\mon-W a,s*ps(Ichneumonida;)
— Braconidce — Other Families — The Ants (Formicidce) — Mutillidce, etc. — Bembicidce —
Pompilidce — Sphegidce — Crabronidce — Philanthidce — Wasps and Bees — Solitary Wasps
and Mud-Wasps (Masaridce and Eumenidce) — Social Wasps (Vespidce) — Solitary Bees
(Andrenidce) — True Bees (Apidce), .......

CHAPTER. II. — Jointed Animals, — continued ; Insects,— continued.
The Flies and Fleas, — Order Diptera.

Characteristics of the Order — Straight- Seamed Flies (Suborder Orthorrhapha) — Mosquitoes
and Gnats (Calicidce) — Daddy- Long- Legs {Tipulidce) — Midges (Chironomidce) — Fungus-
Midges (Mycetophilidce)— Gall-Midges (Cecidomyidce) — Sand-Flies, etc. (Simuliidce and
Bibionidm) — Horse-Flies, or Breeze-Flies (Tabanidce) — Robber-Flies, etc. (Asilidce and
Etnpidw) — Bee-Flies (Bombyliidce) — Circular-Seamed Flies (Suborder Cyclorrhapha) —
Hover-Flies (Syrphidce) — Conopidce — Typical Flies (Muscidce)— Gad-Flies and Bot-Flies
((Estrid(e) — Forest-Flies (Hippoboscidm) — Fleas (Pulicidce, etc.), ....

47

vi CONTENTS

CHAPTER III. — Jointed Animals, — continued ; Insects, — continued.
Butterflies and Moths, — Order Lepidoptera.

Characters of the Order — Development— Structure of Larva — Pupa — Enemies — Mimicry —
Imago, or Perfect Insect — Head — Thorax, and its Appendages — Abdomen — Extinct
Forms— Butterflies (Suborder Ehopalocera) — Classification — Fritillary Group (Nymph-
alidcc) — Erycinidce — Blues and Coppers (Lycamidm) — Skippers (Hesperiidce) — The Moths
(Suborder Heterocera) — Emperor -Moths (Satumiidce) — Silk -Spinners {Bombycidce) —
Hawk-Moths (Sphingidce) — Prominents (Notodontidce) — Clear-Wings (Sesiidce) — Synto-
midce — Burnets (Zygaznida) — Case-Weavers (Psychidce) — Cossidce — Allied Families —
Lasiocampidce — Lymantriidce — Tiger - Moths (A rctiidce) — Owl - Moths (Noctuidcc) —
Loopers (Geometridaz) — Snout-Moths (Hypenidce) — Suborder Microlepidoptera, . . 77

CHAPTER IV. — Jointed Animals, — continued ; Insects, — continued.
The Beetles, — Order Coleoptera.

Characteristics of the Order — Section Pentamera — Tiger-Beetles (Cicindelidce) — Carnivorous
Ground-Beetles (Carabidce) — Carnivorous Water-Beetles (Dytiscidce) — Whirligig Beetles
(Gyrinidce) — Short-Winged Beetles ! (Staphylinidce) — Paussidte—Pselaphidw—BuTxmg-
Beetles {Silphidce) — Hairy-Winged Beetles {Trichopterygidm)—Histeridw — Nitidulidce —
Dermestidce — Hydrophilidce — Stag - Beetles (Lucanidcc) — Passalidce — Tribe Lamelli-
cornia—Buprestidce — Click - Beetles (Elateridce) — Lycidce — Glow - Beetles (Lampyridce)
— Telephoridce — Cleridce — Ptinidce — Section Heteromera — Tenebrionidce — Rhipidophoridce
—-■Meloidce — Stylopidce — Section Tetramera — Weevils (Curculionidce) — Scolytidce —
Brenthidce — Anthribidce — Longicorn Beetles (Cerambycidce) — Bruchidce — Chrysomelidce —
Section Trimera — Lady-Birds (Coccinella), . . . . . .123

CHAPTER V.— Jointed Animals, — continued ; Insects, — concluded. Orders Neuroptera,

Orthoptera, Rhynchota, etc.

Characters of Neuroptera— Caddis-Flies (Suborder Trichoptera) — Phryganeidce, etc. — Flat-
Winged Group (Suborder Planipennia) — Scorpion-Flies (Panorpidce) — Snake-Flies and
Adder-Flies (Sialidce) — Mantis-Flies (Mantispida}) — Nemopteridce — Ant-Lions (Myr-
meleontidce) — Lace-Wing Flies (Hemorobiidce and Chrysopidce) - — Order Orthoptera —
Dragon-Flies (Odonata) — Libellulidce — JEschuidce — Ayrionidce — May-Flies (Eplmneridoi)
— Stone-Flies (Perlidce)— Termites, or White-Ants (Termitidce) — Book- Lice (Psocidw) —
— Bird-Lice (Mallophaga) — True Orthoptera — Crickets (Gryllidce) — Long-Horned
Grasshoppers (Locustidw) — Locust Tribe (Acridiido?) — Stick- and Leaf-Insects (Phas-
midce) — Praying Insects (Mantidce) — Cockroaches (Blattidfc) — Earwigs (Forjiculidce) —
Order Rhynchota — Land-Bugs (Geocorisa) — Water-Bugs (Hydrocorisa) — Cicadas
(Cicadidw) — Lantern-Flies (Fulgoridw) — Frog-Hoppers (Cercopidaz) — Leaf-Flies (Psyl-
lida}) — Plant- Lice (Aphidw) — Scale-Insects (Coccidce) — True Lice (Pediculina) — Order
Thysanoptera — Order Thysanura, . . . . . . .159

CHAPTER VI. — Jointed Animals, — continued. Centipedes, Millipedes, Scorpions,
and Spiders, — Classes Chilopoda, Diplopoda, Arachnida, etc.

Characters of Centipedes — Subclass Anartiostigma — Subclass Artiostigma — Orders Litho-
biomorpha, IScolopendromorpha, and Geophilomorpha — The Millipedes (Class Biplopoda)
— Their Subclasses and Orders — Scorpions, Spiders, Ticks, etc. (Class Arachnida}) —
Their Characteristics — The Scorpions (Order Scorpiones) — The Whip-Scorpion and their
Allies (Order Pedipalpa) — Order Palpigradi — The True, or Web-Spiders (Order
Araneiv) — Segmented Group (Suborder Mesothela) — Typical Group (Suborder Opistho-
thelrf^—The various Tribes and Families of the same — The False Spiders (Order Soli-

CONTENTS vii

PAGE

fugce) — The False Scorpions (Order Pseudoscorpiones) — The Harvest-Spiders (Order
Opiliones) — Suborder Laniatores — Suborder Palpatores — Group Ricinulei — The
Mites and Ticks (Order Acari) — Aberrant Types, ..... 204

CHAPTER VII. — The Jointed Animals, — concluded. The Sea-Spiders, King-Crabs,
Crustaceans, etc., — Classes Pantopoda, Oigantostraca, Crustacea, etc.

Characters of Sea- Spiders— The King-Crabs (Class Oigantostraca)— Existing Forms (Order
Xiphosura)— Order Merostomata— Order Trilobita — Crabs, Lobsters, Crayfish, etc.
(Class Crustacea)— Characteristics of the Class — Typical Crustaceans (Subclass Malaco-
straca)— Order Decapoda — Short- Tailed Group (Suborder Brachyura) — Long-Tailed
Group (Suborder Macrura) — Cleft-Footed Group (Order Schizopoda) — The Mantis-
Shrimps (Order Stomatopoda) — Sessile-Eyed Series (Edriophthalmata) — Order Isopoda
— Order Amphipoda — Subclass Entomostraca — The Barnacles (Order Cirripedia) —
Bivalved Group (Order Ostracoda) — Oar- Footed Group (Order Copepoda) — Order
Cladocera — Leaf- Footed Group (Order Phrjllopoda) — Class Prototracheata, . . 248

CHAPTER VIII. — Stone-Lilies, Star-Fishes, Sea-Urchins, and Sea-Cucumbers,—

Subkingdom Echinodermata.

Characteristics of the Group— Distinction of the Classes— Mode of Life— The Cystids (Class
Cystidea)— The Stone-Lilies or Crinoids (Class Crinoidea) — The Blastoids (Class Blas-
toidea) — The Star-Fishes (Class Asteroidea) — The Brittle Stars (Class Ophiuroidea) —
The Sea-Urchins (Class Echinoidea) — The Sea-Cucumbers (Class Holothuroidea) — De-
velopment of Echinoderms, . . . . . . . . 289

CHAPTER IX.— The Molluscs, or Shell-Fish,— Subkingdom Mollusca.

Definition of the Group — Growth — Coloration — Age— Reproductive System — Food — Organs
of Sense — Locomotion — Uses in Nature and to Man — Noxious Molluscs— Distribution —
Classification — Squids, Cuttle-Fishes, and Nautili (Class Cephalopoda) — Characteristics
— Two-Gilled Group (Order Dibranchiata) — Octopus Tribe (Octopodidre) — Other Families
— Argonautida: — Suborder Decapoda — Squids (Loliginidm) — Sepiolidce— Onyclioteuthidm
and Chiroteuthidw — The Cuttle-Fishes (Sepiida^) — Spirulidw — Four-Gilled Group (Order
Tetrabranchiata) — Nautilida; — Allied Families, ...... 320

CHAPTER X. — The Molluscs,— continued. Class Gastropoda.

Distinctive Features of Gastropods— Lung-Breathing Group (Order Pulmonata) — Suborder
Stylommatophora — Shelled Slugs (Testacellidce) — True Slugs (Limacidai) — The Snail
Tribe (Helicidce) — Other Families — Suborder Basommatophora — Earlet Shells (Auri-
culidw) — Pond-Snails, etc. (Limnceidw., Physida?, and Chilinidre) — Hind-Gilled Group
(Order Opisthobranchiata) — Naked-Gilled Subgroup (Suborder Nudibranchiata) — Sec-
tion Anthobranchiata — Doris Tribe (Doridopsida', Doridaz, etc.) — Section Inferobranchiata
— Section Polybranchiata — Section Pellibranchiata — Section Parasita — Covered-Gilled
Subgroup (Suborder Tectibranchiata) — Suborder Pteropoda — Sections Gymnosomata and
Thecosomata — Front-Gilled Group (Order Prosobranchiata) — Suborder Pectinibranchiata
— Section Toxoglossa — Cones (Conida?) — Auger -Shells (Terebrida) — Pleurotomidce —
Cancellariida) — Section Bhachiglossa — Olives (Olividai) — Harps (ffarpida) — Marginellidm
— Volutes {Volutidai) — Tulip-Shells (Fasciolariidat) — Conch-Shells (Turbinellida?)—
Whelks - (Buccinidce) — Dog- Whelks i (Nassidas) — .Dove-Shells - (Columbellidw)— Murices
(Muricida:)— Section Tamioglossa — Tritons {Tritonidcv) — Tun-Shells (Doliidai) — Cowries
(Cyprceidm) — Wing-Shells (Strombidaz) — Cerithiidce— Worm-Shells ( Vermetidce) — Melan-
iidas — Strepopomatidaz — Periwinkles (Littorinidce) — Rissoidw — Hydrobiidai — Viviparous

viii CONTENTS

PAGE

PondSnails(Viviparidce) — Valvatidce — Ampullariidce — Cyclophoridce — Cyclostomatidce—^
Truncatellidce — Hipponychidai — Calyptrceidce — Xenophoridce — Naticidce — Section Pteno^
ylossa— Violet Snails (lanthinidce)— Wentle-Traps (Scalariidce) — Section Gymnoglossa — I
Eulimidce — Pyramidellidce — Suborder Heteropoda — Pterotracheidce — Atlantidce — Sub-
order Scutibranchiata — Section Rhipidoglossa — Helicenidce — Neritidce — Turbinidce —
Trochidce — Delphinulidce— Ormers {Haliotidoz) — Pleurotomariidce — Keyhole Limpets
(Fissurellidce)— Section Docoglossa — Acmceidce — Limpets (Patellida?) — Lepetidce,. . 341

CHAPTER XL — Molluscs, — concluded. Classes Amphineura, Scaphopoda, and Pelecypoda.

The Chiton Group (Class Amphineura) — Chitons (Order Polyplacophora) — Order Aplacophora
— The Tooth-Shells (Class Scaphopoda) — The Bivalves (Class Pelecypoda)— Order Proto-
branchiata — Order Filibranchiata — Order Pseudolarnellibranchiata — Order Eulamelli-
branchiata— Suborder Submytilacea — Suborder Tellinacea — Suborder Veneracea — Sub-
order Cardiacea — Suborder Myacea — Suborder Pholadacea — Suborder Anatinacea
— Order Septibranchiata, . . . . . . . ., : . 398

CHAPTER XII. — Moss- Animals and Lamp-Shells, — Subkingdom Molluscoidea.

The Moss-Animals (Class Bryozoa) — Characteristics of the Group — Subclass Ectoprocta — Order
Phylactolmmata— Order Gymnolmmata — Subclass Entoprocta — The Lamp-Shells (Class
Brachiopoda) and their Characteristics — Hinged Group (Order Testicardines) — Hinge-
less Group (Order Ecardines), . . . . . . . 419

CHAPTER XIII. -The Worm-Like Animals,— Subkingdom Vermes.

Characteristics of Worms — Bristle- Worms, or Annelids (Class Annelida) — Their Distinctive
Features — Many-Bristled Group (Order Polychaita) — Sparsely-Bristled Group (Order
Oligochceta) — The Leeches (Class Hirudinea) — The Gephyrean Worms (Class Gephyrea)
The AVheel- Animalcules (Class Rotifera) — The Thread-Worms, or Round-Worms (Class
Nematohelminthes) — Spiny-Headed Thread-Worms (Order Acanthocephala) — Typical
Thread-Worms (Order Nematoidea) — Arrow-Worms (Order Chcetognatha) — The Nemer-
tine Worms (Class Nemertinea) — The Flat- Worms (Class Platyhelminthes) — Tape-
Worms (Order Cestoda) — Trematode Worms (Order Trematoda) — Many-Suckered Group
(Suborder Polystomeai) — Two-Suckered Group (Suborder Distomew) — Turbellarian
Worms (Order Turbellaria) — Suborder Rhabdocoela — Suborder Dendrocala — Group of
Uncertain Position (Orthonectidos and Dicyemidce), ..... 432

CHAPTER XIV. — Jelly-Fish, Corals, and Sea- Anemones, — Subkingdom Cailenterata.

Distinctive Features of Ccelenterates — The Ctenophores (Group Ctenophora) — Stinging Series
(Group Cnidaria)— The Jelly-Fish and their Allies (Class Polypomedusas) — Order
Siphonophora— Order Hydromedusa — Fresh-water Forms — Order Scyphomedusm — The
Sea- Anemones and Corals (Class Anthozoa) — Six-Rayed Polyps (Order Hexactinia)—
Horny Corals (A ntipatharia) — Eight-Rayed Polyps (Order Octactinia) — Coral-Reefs and
Islands, . . . . .'■■•. . , . 474

CHAPTER XV.— The Sponges— Subkingdom Porifera.

Distinctive Characters of the Group — Reproduction— The Calcareous Sponges (Class Calcarea)
— Six-Rayed, or Glass-Sponges (Class He;cactinellida) — The Common Sponges (Class
Demospongia) — Four-Rayed Sponges (Order Tetractinellida) — The Fleshy Sponges
(Order Carnosa) — Single-Rayed Sponges (Order Monaxonida) — Fresh-Water Sponges —
Horny Sponges (Order Ceratosa), . . . . - . . . •. f>26

CONTENTS

IX

CHAPTER XVI.— The Lowest Animals,— Subkingdom Protozoa.

Characteristics of Protozoans — The Root-Footed Group (Class Rhizopoda) — The Amaebas
(Order Lobosa) — Order Foraminifera — Sun- Animalcules (Order Heliozoa) — Order
Radiolaria — The Infusorial Animalcules (Class Infusoria) — Flagellated Infusorians
(Order Flagellata) — Ciliated Infusorians (Order Ciliatar), .... 550

Index

569

g|lllg/gia£flga

LIST OF ILLUSTRATIONS

COLOURED PLATES

Typical Butterflies,
Mimicry in Insects,
Giant Swift Moth,
Beetles in a Flood,
Orthoptera,
Crustaceans,
Cephalopoda,
Land Molluscs,
Ctenophores,
Sea-Anemones,
Glass-Sponges,
Radiolarians,

Frontispiece
Facing page 10
103
12a

„ 176
256
336

„ 345

„ 475
50O

„ 537
562

PAGE PLATES

A Column of the Army-Worm,
Insect Life in Summer,
Hermit Crabs, .

Page 53
„ 65
„ 263

TEXT ENGRAVINGS

PAGE

I'AGE

Group of Beetles (Bruchus),

1

Ichneumon- Wasps,

24

Mouth Organs of Insects, .

7

Various Ichneumon-Wasps,

25

Group of Saw- Flies,

15

Pimpla instigator, .

25

Boring Apparatus of Giant- Tailed Wasp,

16

Microgaster nemorum,

26

Giant- Tailed Wasp,

17

Javelin-Wasp,

26

Pine Saw-Fly and Broad-Bodied Saw-Fly,

17

Burnished and Gold Wasps,

27

Saw- Flies, .....

18

Honey-Pot and Parasol Ants,

31

Green Saw-Fly, ....

19

Mutilla and Scolia,

33

Oak-Gall Wasp, etc.,

20

Pompilus, etc.,

34

Sponge Gall- Wasp, Oak-Root Gall-Wasp,

Mellinus, etc.,

35

etc., .....

20

Leaf-Cutter Bee, .

36

Rose Gall- Wasp and Gall,

21

Inmates of a Hive, .

38

Egg- Wasps, ....

22

Mud- Wasps,

40

Gouty-Legged Wasp, Chrysalis-Stinger,

Life-History of the Hornet,

41

etc.,

23

South African Wasp and Nest,

42

LIST OF ILLUSTRATIONS

XI

Group of Solitary Bees,

PAGE

43

Mason-Bee,

43

Carpenter- Bee,

44

Flower-Bees,

44

Humble-Bees,

45

Wing of Daddy-Long- Legs and Blow-Fly

48

Banded Gnat,

50

Army- Worm Fly, .

55

Development of Hessian Fly,

57

Columbatsch Fly, .

58

St. Mark's Fly, .

58

Great Horse-Fly, .

59

Robber- Flies, .

60

Black and White Bee-Fly,

61

Female Stratiomys,

61

Hover-Fly,

62

Group of Flies and their Grubs, .

67

Tsetse Fly, ....

69

Spiny Fly, .

71

Asparagus Fly,

71

Chlorops tasniopus, .

72

Development of Horse Bot-Fly, .

72

Ox Warble-Fly and its Development,

73

Life-History of Sheep Bot-Fly,

74

Forest-Fly,

75

Common Flea and its Structure, .

76

Pine Hawk-Moth, with Larva) and Pupa,

77

Wing of Noctua Moth,

82

Peacock and Meadow-Brown Butterflies,

86

Resplendent Ptolemy,

87

Wall-Brown,

88

Group of British Butterflies,

89

Group of Tropical Butterflies,

90

Black- Veined White,

91

Hawk-Moths,

93

Spurge Hawk-Moth and Caterpillar,

96

Oleander Hawk-Moth, with Larva anc

Pupa, ....

97

Puss-Moth and Lobster-Moth

100

Hornet Clear- Wing and Goat-Moth,

101

Psyche Moth,

102

Life-History of Pine-Lappet Moth,

105

Procession-Moth, .

106

Lackey-Moth,

107

Hermaphrodite Gipsy-Moth,

107

Development of Gipsy-Moth,

108

Black- Arches Moth,

108

Pale Tussock-Moth, with Larva and Pupa

109

Brown-Tail and Gold-Tail Moths,

109

Satin- Moth,

110

Tiger - Moth, Six - Spot Burnet, am

...

Spangled White,

Ill

Merveil-du-Jour, Rustic Shoulder-Knot

and Figure-of-Eight Moth, .

112

White-Spotted Pinion and Pine-Moth,

PAGE

113

Red Under- Wing, with Larva,

113

Feathered Gothic, Angle - Shades, anc

I

Antler- Moth, .

114

Pepper-Moth, with Larva and Pupa

115

Group of Loopers,. .

116

Bordered White, and Argent- and Sable

Moth, ....

116

Magpie Moth and its Development,

117

Dark Spinach-Moth and Larva, .

117

Purple-Barred Yellow, and Lime-Speck

Moth, ....

117

Mother-of-Pearl Moth, with Larva,

118

Oak-Tortrix and its Development,

119

Oak-Gall Tortrix, and Larch Tortrix,

119

Pea-Moth and Larva,

120

Codlin and Meal-Moth,

120

Corn-Moth, and Larva of Clothes-Motl

L

and Wax-Moth,

121

Plume-Moth, etc., .

121

Larch Mining-Moth,

122

Carnivorous Beetles and their Prey,

124

Zabrus and Larva, .

128

Tiger-Beetles,

130

Elaphrus riparius, .

131

Mormolyce phyllodes,

132

Scarites gigas,

132

Dytiscus and Hydrochai'is, .

133

Whirligig Beetle, .

134

British Rove-Beetles,

135

Claviger testaceus, .

137

Silpha atrata and Larva, .

138

Hister fimetarius, .

138

Meligethes ceneus,

139

Great Black Water-Beetle,

141

Burrowing Beetle, .

142

Scarabceus sacer,

142

Aphodius fossor,

142

Male of Geotrupes, .

143

Polyphylla fullo,

143

Summer Chafer,

144

Rhinoceros-Beetle,

144

Ceratorrhina smithi,

145

Chalcophora mariana,

145

Wire- Worm,

145

West Indian Fire-Fly,

146

Telephorus fuscus, .

146

Clerus formicarius, with Larva and Pupa,

146

Trichodes apiarius,

146

Death- Watch Beetle,

146

Churchyard Beetle and Larvil,

147

Meal-Worm Beetle and Larva,

147

Oil-Beetles and Larvae,

148

Male and Female of Xenos,

148

Xll

LIST OF ILLUSTRATIONS

PAGE

Sitones lineatus,

149

Pine- Weevil, with Larva and Papa,

149

Apion apricans,

150

Leaf- Rolling Weevils, . ,

150

Apoderus longicollis,

150

Nut- Weevil and Larva,

. 151

Pear- Blossom Weevil,

151

Apple-Blossom Weevil, . .

151

Various Weevils, . . .

151

Palm- Weevil,

152

Hylotrxipes bajidus, with Larva,

152

Prionus and Er gates, . . ■

153

Musk-Beetle,

154

Strangalia armata and Larva,

154

Toxotus meridianus,

154

Rhagium, ....

155

Necydalis major,

155

Long- Horned Beetles,

156

Donacia clavipes, .

156

Colorado Potato-Beetle,

157

Life-History of Tortoise-Beetles, .

157

Lady -Birds,

158

Cases of Caddis-Fly Larvae,

160

Life-History of Caddis-Fly,

162

Common Scorpion-Fly,

163

Life- History of Alder-Fly,

163

Life-History of Ant-Lion,

164

Lace- Wing Flies, .

165

Life-History of Dragon-Flies,

168

Male May-Fly,

170

May-Fly Moulting, . . , .

170

Common Stone- Fly, . .

171

White Ants and their Development,

173

Psocus lineatus,

176

Group of Crickets,

177

Mole-Cricket, with Eggs and Larva,

178

Hetrodes and Meconema,

179

Migratory Locust and Larvce,

181

Tettix subulata,

182

A Stick-Insect and Larva,

183

Praying Insects,

184

Egg-Case of Kitchen Cockroach, .

185

Cockroaches, .

185

Earwigs, ....

186

Hottentot Bug,

188

Shield Bugs,

189

Syromastes and Neides,

189

Pyrrhocoris apterus,

190

Calocoris striatellus

190

Tingis, Aradus, and Cimex,

191

Reduvius personatus, . . .

191

Salda elegantula, .

191

Common British Water-Bugs,

192

European Cicadas, . * ' .

193

Cixius nervosus,
Pseudophana euwpma,
Ledra and Aphrophora,
Gentrotus comutus, .
Psylla genistas,

Life-History of Vine-Phylloxera,
Lachmis punctatus,
Spruce-Gall Aphid,
Female Orthezia urticw,
Cochineal Insects, .
Various Lice,
Corn-Thrips,
Heliothrips,
Podura villosa,
Desoria glacialis,
Black-Banded Centipede, .
Common English Centipede,
Centipede devouring a Beetle Larva,
Head of Geophilus,
Geophilus grappling with Earth- W
Suinatran Millipede,
Bristly Millipede, .
Sumatran Pill-Millipede,
English Pill-Millipedes,
Millipede (Julus), .
Flat Millipede,
Celebean Millipede,
Spanish Yellow Scorpion,
African Rock-Scorpion,
Bornean Whip- Scorpion,
West African Tailless Whip-Scorpion,
Anatomy of Cross-Spider,
Female Drassns,
Female Wolf-Spider,
Jamaica Trap-Door Spider and Nest,
Bird-Eating Spider,
Palm Trap-Door Spider,
Field-Spiders,
House-Spiders,
Water-Spiders,
An Orb-Spinner, .
Common Cross-Spider,
Side-Walking Spiders (Xysticus),
Side- Walking Spider (Palystes),
Tarantula, .
Jumping Spiders, .
False Spider,
Book Scorpion,

South American Harvest Spider,
Chilian Harvest Spider, .
Velvety Mite,
Water Mite, and Water Scorpion infested
with same, ....
Beetle-Mite, and Dor Beetle infested with same

243
243

LIST OF ILLUSTRATIONS

xm

Mouth- Organs of Sheep-Tick

English Sheep-Tick,

Dog- or Sheep-Tick,

Pigeon-Tick,

Cheese-Mite

Itch-Mite, .

Demodex folliculorum,

A Spider's Spinnerets,

Slender Sea-Spider,

Shore-Spider,

Chinese King-Crab,

A Trilobite,

Nauplius Larva of Barnacl

Zoaea Stage of Crab,

Jaws of Crayfish, .

Young Edible Crab,

Swimming Crab, .

Indian Land-Crab,

Swift Land-Crab, .

Calling-Crab,

Thornback Crab, .

Long-Beaked Spider-Crab

Dromia Crab,

Broad-Clawed Porcelain-Crab,

One- Clawed Lobster,

Larva of Crayfish, .

Slender-Clawed Crayfish,

Common Crayfish,

Common Prawn, .

West Indian Prawn,

Mussel-Prawn and Sponge-Prawn

Hooded Shrimj), .

Long-Necked Shrimp,

Mantis-Shrimp,

Serolis bromleyana, .

Sphieroma, .

Male and Female Gnathia,

Common and Pill Wood- Lice,

Fresh-Water Shrimp,

Sand-Hopper,

Spiny Shrimp,

Gigantic Andania,

Skeleton-Shrimp, .

Whale- Louse,

Transparent Ocean-Shrimp

Phronima, .

Barnacles attached to Pumice

Acorn-Barnacle,

Stalkless Barnacle,

Parasitic Cirripedes,

Parasitic Barnacles,

Copepods, .

Fish- Lice, .

Spiny-Tailed Water-Flea,

PAGE

PAGE

244

Egg-Capsule of Water-Flea,

285

244

Glassy Leptodora, . . . .

286

245

Scale-Tailed Apus,

286

245

Branchipus, and Brine Shrimp, .

287

245

Peripatus, . . . . .

288

246

Anchor Sea- Cucumber,

290

246

Sea-Cucumbers and Brittle-Star, .

291

247

Ambulacral System of Starfish, .

292

248

Group of Stone- Lilies,

294

249

Lofoden Boot-Crinoid,

297

250

Medusa-Head Pentacrinid,

299

252

Rosy Feather-Star and Sabella, .

300

253

Parasitic Swellings on Crinoids, .

303

254

Blue China Star-Fish,

304

254

Pedicellarice,

305

256

Starfish Turning Over,

306

256

Common Brittle-Star,

307

257

Edible Sea-Urchin,

308

258

Jaws of Stone -Urchin,

309

258

Shield-Urchin,

309

259

Fiddle Heart-Urchin,

310

261

Phial- Shaped Pourtalesia,

311

261

Leather-Urchin, .

311

262

U-Shaped Sea-Cucumber, .

312

265

A Deep- Sea Holothurian (Scotoplana),

313

266

„ „ (Psychropotes),

314

266

Club-Like Sea-Cucumber,

314

267

A Plated Holothurian,

314

268

Green Snake-Star, .

315

269

Development of a Sea-Urchin (Stages 1-8)

316

270

„ „ (Stage 9),

316

270

„ „ (Stage 10),

317

271

Young Sea-Urchin,

318

272

Brood- Pouch of Sea-Urchin,

319

274

Beak of Cuttle-Fish,

327

275

Common Octopus, .

329

275

Shell of Female Argonaut, . ,,

332

276

Male Argonaut,

333

277

Common Squid,

335

277

Sepiola, ....

336

277

Shell of Spirula, .

338

278

Section of Shell of Pearly Nautilus,

339

278

A Ceratite, ....

. 340

279

An Ammonite,

. 340

279

Shell-Bearing Slug (Testacella),

343

280

Glass-Snail and Amber-Snail,

. 344

281

Black Slug,

345

282

Clatisilia, ....

347

282

Agate-Snail (Achatina),

. 348

282

Pythia scarabceus, .

. 349

282

Earlet Shell (Auricula), .

349

283

Embryo of River- Limpet, .

. 350

284

Teeth of Snails, .

. 350

285

Common Pond-Snail (Limnrea), .

351

XIV

LIST OF ILLUSTRATIONS

Various Forms of Limn&a,

Ramshorn Snail (Planorbis),

Circulation in Pleurobranchus,

Acanthodoris spinosa,

Ancula cristata,

Tethys leporina,

Dendronotus arborescens,

Phyllirhoe bucephala,

JEoli&ia papillosa, .

Elysia viridis,

Limapontia capitata,

Synapta digitata with parasitic Entoconcha

Larva of Entoconcha,

Acera bullata,

Philine aperta,

Sea- Hare (Aplysia),

Pleurobranchus peroni,

Larva of Pneumoderma,

Clione,

Cavolinia tridentata,

Larva of Cavolinia,

Gleba cordata,

Animal of Periwinkle,

Textile Cone,

Black Olive,

Teeth of Whelks, .

Section of Whelk, .

Animal of Murex, .

Egg-Capsules of Purpura,

Rhizochilus,

Helmet- Shell (Cassis),

Tun-Shell (Dolium),

Fig-Shell (Pyrula),

Money-Cowries,

Wing-Shell (Strombus),

Pelican's Foot (Aporrhais)

Worm-Shell ( Vermetus),

Spawn of Periwinkle,

Horned Winkle (Lacuna),

Rissoa,

Viviparous Pond- Snails,

Teeth of Vivipara,

Star-Fish with Thyca,

Violet Sea-Snail, .

A Pelagic Heteropod (Pterotrachea),

Atlanta peroni,

Freshwater Nerite,

Dolphin- Shell ( Delphinula),

Under Surface of Limpet,

Common Chiton, .

Larva? of Chiton, .

Eyed Chiton,

Common Tooth-Shell,

Section of Animal of Dentaliurn

PAGE

PAGE

351

Soft-Parts of River-Mussel,

401

352

Anatomy of River- Mussel,

402

353

Left Valve of Meretrix,

. 403

354

Right Side of Anomia, with Shell Re

356

moved,

. 404

357

Common Mussel Closed and Attached bi

7

357

Byssus,

. 405

358

Common Mussel Opened, .

. 406

359

Date-Shells in the Rock, .

406

359

Pearl- Oysters,

. 407

360

Valve and Soft-Parts of Common Oyster,

408

361

Margin of Mantle of Pecten,

. 409

362

File-Shell in its Nest,

. 409

362

Large River-Mussel,

411

363

Pearl-Mussels and Pearls, .

. 412

363

A Valve and Soft- Parts of Tridacna,

414

364

Animal and Case of Rocellaria,

416

367

Pholas in its Burrow,

416

367

Ship- Worm and its Larva, • .

417

368

Brechites vaginiferus,

. 418

368

Section of Paludicella,

. 420

369

Lace Coral (Retepora),

. 421

369

Lepralia, ....

. 422

371

Sea Mat (Flustra), .

. 423

373

Tubulipora verrucosa,

. 424

376

Cristatella and Young,

. 425

377

A Fixed Moss- Animal,

. 426

379

Back Valve of Terebratulina,

. 428

380

Development of Thecidium,

429

380

Thecidium mediterraneum, .

430

381

Upper Valve and Animal of Crania,

. 431

382

Lingula pyramidata,

431

383

Group of Bristles of an Annelid, .

432

384

Parapodium and Bristles of Annelic

I

384

(Heteronereis), .

433

385

Sea-Mouse (Hermione)

434

385

Head of Nereis,

434

386

Various Annelids, .

435

387

Arenia fragilis,

436

387

Chaztopterus,

437

388

Tube-Worm (Hermella),

437

389

Common Serpula, .

438

391

Sabella,

438

391

Common Earth-Worm,

439

393

Phreoryctes menkeanus,

439

394

Beaked Nais,

440

395

Myzostoma gigas, .

441

396

Common Leech,

442

397

Structure of Leech,

442

398

Rock- Leech,

443

399

Gephyrean Worms,

444

399

Four- Horned Rotifer,

446

400

Flower Animalcule,

447

401

Spiny- Headed Thread-Wo

cm,

448

LIST OF ILLUSTRATIONS

xv

Front End of Thread-Worm,

PAGE

449

Development of Thread-Worm, .

450

Vinegar-Eel,

451

Rhabditis and Ilhabdonema,

451

Humble-Bee Thread-Worm,

452

Human Round Worm,

453

Head of Round Worm,

"453

Human Thread-Worm,

454

Dochmius duodenalis,

454

Head of Cucullanus elegans,

454

Trichinosis Worm Coiled Up,

455

Trichina spiralis, .

455

Larvae of Gordius, .

456

Eggs and Larva of Mermis,

456

Arrow- Worm,

457

Proboscis of Tetrastemma, .

457

Four-Eyed Nemertine (Tetrastemma),

458

Cross-Bearing Nemertine, on a Coral,

459

A Nemertine (Pterosoma), .

460

Pilidium Larva, with Nemertine Worm,

461

Human Tape- Worms,

461

Egg and Embryo (Proscolex) of Tape-

Worm,

462

Bladder- Worm Stage (Cysticercus) of Tape-

Worm,

462

Toznia echinococcus,

463

Broad Tape-Worm,

463

Trematode Worms,

464

Life-History of Double-Worm,

465

Dactylocotyle and Anthocotyle,

466

Polystomum and Larva,

467

Liver-Fluke and Larva, .

467

Development of Distomum,

468

Larval Form of Liver- Fluke,

468

Mesostomum tetragonum, .

469

Trematodes,

470

Schizostoma productum,

470

Single-Eyed Turbellarian (Stenostomum),

471

Structure of a Dendroccelian,

472

Smooth Polycelis, .

472

Two-Striped Geodesmus, .

472

Planarian Worm (Planaria),

472

Tufted Planarian (Thysanozoum), .

473

Mhopalura, ....

473

A Dicyemid,

473

Cydippe,

476

Venus' Girdle,

478

Stinging Capsules,

.

480

Physophora,

.

482

Stephalia, .

.

483

Clavatella, .

.

485

Pedis,

485

Corymorpha, with Detached Medusae,

486

Monocaulus,

487

Group of Hydractinia,

Hydractinia on a Whelk-Shell,

Millepora, .

Hydra Monster, Artificially Produced,

Chrysaora, .

Ehizostoma,

Periphylia, .

Tessera,

Monoxenia darwini,

Development of Monoxenia,

Sections of Monoxenia,

Outline of Caulastrwa,

Larvae of Sea- Anemone, .

A Sea- Anemone (Actinia),

Endive- Leaved Anemone, .

Short- Ten tacled Anemone,

Parasitic Anemone (Palythoa), on Glass

Rope Sponge, .
Palythoa axinellcc, .
A Simple Coral (Thecocyathus),
Scarlet Crisp Coral (Flabellum),
Mushroom-Coral (Fungia),
A Deep-Sea Coral (Leptopenus),
A Branching Coral (Dendrophyllia),
A Madrepore Coral (Madreporia),
A Massive Coral (Astroides),
Developmental Stages of Astroides,
A Star-Coral (Astr&a),
A Brain-Coral (Meandrina),
Mouths of Brain-Coral,
A Horny Coral (Antipathes),
An Alcyonarian Coral (Alcyonium),
A Sea-Pen (Pteroides),
Umbellula thompsoni,
Umbellula encrinus,
A Sea-Fan (Gorgonia),
Corkscrew Sea-Fan (Streptocaulus),
Red Coral, ....
Organ-Pipe Coral (Tabipora),
Structure of Tubipora,
Island with Fringing- and Barrier-Reefs,
Coral- Island, or Atoll,
Section through a Coral- Reef,
Diagram Explaining Theory of Subsidence
Outline of the Island of Aiva,
Mouths of Madrepore,
Bread-Crumb Sponge, Showing Currents,
Flagellated Chambers of Sponges,
Sponges Growing on Seaweed,
Carpenter's Glass- Sponge,
Structure of Venus' Flower-Basket,
An Ascon Sponge, .
Structure of Toilet-Sponge,
Calcareous Ascon Sponge (Leucosolenia),

PAOK

488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
502

503
504
505
505
506
506
507
507
508
509
509
510
510
510
512
513
514
514
515
516
517
517
517
520
521
522
524
524
525
526
527
528
530
532
532
533
534

XVI

LIST OF ILLUSTRATIONS

A Calcareous Leucon Sponge (Leucandra)

Development of Sycon raphanus, .

Siliceous Sponge- Spicules,

Siliceous Spicules of Anchor-Sponges,

Sea Kidney Leather-Sponge (Chondrasia)

A Single-Rayed Sponge (Axinella),

Siliceous Spicules of Monaxonid Sponges,

Esperiopsis challengeri,

Limestone Bored by Sponge,

Embryo of Fresh- Water Sponge, .

Section of Common Bath-Sponge,

Ascetta primordialis,

Proteus Animalcule,

Proteus Animalcule (highly magnified),

Orange-Coloured Protomyxa,

Young Capsuled Animalcule (Arcella),

Egg-Shaped Gromia,

Hyperammina and Astrorhiza,

PAGE

535
536
537
540
541
542
542
543
544
545
546
547
550
551
553
553
554
555

Peneroplis pertusus,

Structure of Orbitolite, . .

Polymorphina,

Shells of Globigerina,

Polystomella,

Sarcode Body of Polystomella,

Green Sun- Animalcule (Acanihocysti

Lattice- Animalcule,

Mail-Coated Flagellata,

Phosphorescent Animalcule (Noctiluca),

Pyrocystis, ....

Mussel- Animalcule (Stylonychia), .

Bell- Animalcule (Vorticella), .

Nodding Bell- Animalcule (Epistylis),

Rosel's Trumpet- Animalcule (Stentor),

Marine Animalcule (Acineta),

Bud-Bearing Animalcule (Hemiophrya),

Spiral-Mouthed Animalcule (Spirostomum),

556
556
557
557
558
559
560
561
563
563
564
564
565
565
566
567
568
568

THE ROYAL NATURAL HISTORY.

INVEBTEBBATE ANIMALS.

CHAPTER I.

The Jointed Animals, — Subkingdom ARTHROPODA.

The Insects, — Class Insecta.

Ants, Wasps, Bees, etc., — Order Hymenoptera.

_. . In the early days of zoological science, when the value in classification

Distinction J J .

between Verte- of the structural and embryological characters of living beings was

brates and in- but little understood, the animal kingdom was divided into two
subkingcloms called Vertebrata and Invertebrata ; the former embrac-
ing those forms provided with a vertebral column, or backbone, and the latter those
that were not so provided. With the addition of some few classes, whose organ-
isation has only recently been fully comprehended, the Chordata of to-day are
coextensive with the Vertebrata of half a century ago. But the term Invertebrata,
as denoting a natural assemblage of animals, has long ceased to be used by every
competent zoologist, and is nowadays merely applied as a conveniently vague title
for all the animals that have not acquired the characters of the Chordata. This
change of opinion has been brought about by the attainment of a far more intimate
acquaintance with the structure and development of the lower animals than our
predecessors, with their less refined methods of investigation, could possibly

VOL. VI. — I

2 INVERTEBRATES.

possess ; and it has resulted in the splitting up of the so-called invertebrates into
a number of subkingdoms, each of which is equivalent to the entire group of
Chordata.

It must not, however, be supposed that no advance has been made of late
years in chordate morphology, and that the conception of the essential characters
of the group is the same as it was in the earlier part of the century. So far
indeed is this from being the case, that the zoologists of those days would certainly
be greatly puzzled to understand the reasons for the present wide extension of the
group to embrace such forms as the sea-squirts and the worm-like Balanoglossus,
which have no vertebral column, and do not even present the outward semblance
of any of the classes of the true Vertebrata. Strictly speaking, therefore, they
are not Vertebrates at all ; yet their claim to be ranked in the same great category
of animals as the lancelet, which also has no backbone, and the fishes, is now generally
accepted, and is based in the main upon their possession, in common with all the
true Vertebrates, of three characteristics not found in any other group of the animal
kingdom. These are, firstly, the presence of slits in the lateral walls of the pharynx,
by means of which the anterior part of the alimentary canal is put into communica-
tion either with the body-cavity or directly with the outer world ; secondly, the
existence, either as a temporary or permanent structure, of a cartilaginous rod, the
notochord, lying lengthwise in the upper part of the body ; and, thirdly, the position
of the principal nervous tract, also in the upper part of the body, but above the
notochord. The fate of the notochord in the different classes of Chordates is some-
what varied. In some of the sea-squirts, for instance, it persists only in the tail,
which may entirely disappear when the animal settles down to its sedentary life.
Hence these creatures are sometimes called the Urochordata, or rod-tailed. In the
lancelet, however, this structure remains throughout life, and extends from the end
of the tail to the extremity of the head. Hence the section containing this little
fish-like creature is called Cephalochordata, or rod-headed. In all the higher
members of the assemblage, however, that is to say, in fishes, amphibians, reptiles,
birds, and mammals, the notochord falls short of the front end of the head, ter-
minating j ust behind a point which in the floor of the skull eventually becomes
the pituitary fossa. Moreover, in all the forms that acquire a bony skeleton, this
rod is to a greater or less extent replaced by the bodies, or centra of the vertebras,
or segments composing the backbone ; these centra supporting the bony arches
developed for the protection of the dorsal nerve-chord. No less varied is the fate
of the pharyngeal slits, or visceral clefts. Whereas in the lower Vertebrata, such
as fishes, these remain as the branchial slits, in the adults of the more highly
organised forms, like mammals, they practically disappear, one only remaining as
the eustachian tube, by means of which the back of the mouth communicates with
the inner chamber of the ear.

With this brief resume of the fundamental features of Chordate morphology,
we may turn to the remaining groups of animals, the so-called In vertebrata, which,
as a whole, may be distinguished from Chordates merely by negative characters,
there being no pharyngeal slits, no notochord, and no central nervous system
running along the back. Nevertheless, some of the higher groups of invertebrated
animals — such as the Arthropods and Molluscs — resemble each other, and differ

GENERAL CHARACTERISTICS. 3

from the Vertebrates in the arrangement of some of the principal organs of the
body. For instance, although as in Chordates the front end of the nervous chord
is lodged in the head above the mouth, and constitutes the brain, the rest of it
runs along the ventral or lower surface of the body beneath and not above the
alimentary canal, which thus, in its anterior or oesophageal part, passes right
through a ring or collar of the nervous system. Again, the chief centre of the
circulation, the heart, is lodged in the back and not in the lower part of the body, so
that the arrangement of these two structures is exactly the opposite of that which
obtains in the Chordata. If, for example, a transverse section be • cut through a
fish a little behind the head, the nerve-chord, the alimentary canal, and the heart
will be found to occupy the following positions — the first named being in the back,
the second in the middle, and the third below ; while, on the contrary, a section of
the same kind, taken in substantially the same place in a centipede, will show that
the heart is above, and the nerve-chord below the alimentary canal.

This arrangement of the organs in question does not, however, exist in all
invertebrated animals. In some the nervous system is absent ; in others it con-
sists of two strands, one running along each side of the body, and neither above
nor below the alimentary canal. In others, again, there is no circulatory system,
and in others no alimentary canal. There is consequently an extreme divergence
in anatomical structure between various kinds of Invertebrates, and zoologists
have attempted to express these differences, as explained above, by the referring
these various creatures to distinct subkingdoms.

Eight of such subkingdoms are provisionally recognised in the present work,
and are arranged as follows: — (1) Arthropoda, or Invertebrate animals with jointed
legs, such as insects, spiders, and crustaceans ; (2) Echinodermata, or star-fish, sea-
urchins, stone-lilies, etc.; (3) Mollusca, or soft-bodied, unsegmented animals, often
with a shell, but without legs, like cuttle-fish, whelks, and oysters ; (4) Molluscoida,
including the lamp-shells and corallines ; (5) Vermes, or worms and their
kindred ; (6) Ccelenterata, or jelly-fish, sea-anemones, and corals ; (7) Porifera, or
sponges ; and (8) Protozoa, or single-celled animals, like the microscopic foramin-
ifera. As the special characters of each of these subkingdoms are pointed out in
the chapters devoted to them, no further reference is necessary in this place.

Special ^^e term Arthropoda is applied to the classes of animals com-

Characters of posing this subkingdom in allusion to the fact that the limbs are
Arthropods, divided by joints into a series of movable segments. The title, how-
ever, is not in all respects satisfactory, seeing that members of other groups,
mammals and birds for instance, also have jointed legs, and in one important
though not typical class of Arthropoda, namely, the Prototracheata, containing the
aberrant family Peripatidce, the appendages are short and undivided. The name
is consequently often superseded by the later but more appropriate term Gnatho-
poda, meaning foot -jawed, which refers to a characteristic that is perfectly
distinctive of all the species included under the heading. This is the transforma-
tion into jaws, or gnathites, as they are sometimes called, of one or more pairs of
the appendages that lie at the sides of the mouth, or just behind it. The number
of pairs involved in the formation of jaws varies from one to six, the smallest being
found in Peripatus, and the largest in crabs and their allies, while between these

4 JOINTED ANIMALS.

two extremes we meet with two pairs in the Millipedes, three in the Insects, and
four in the Centipedes.

The appendicular nature of the jaws, then, is the most distinctive feature of
the animals now under discussion. But if two members of the Arthropoda, say for
instance a lobster and a centipede, be compared together, they will be found to
possess many other structural characters in common. Thus the body is bilaterally
symmetrical, that is to say, if it be cut exactly in half lengthwise, the right and
left portions will be precisely alike. It is, moreover, divided into a series of
segments, placed one behind the other in a long series ; each segment bearing a pair
of limbs, which in the centipede are all alike, but in the lobster vary considerably
in size and structure in different regions of the body. In both types, moreover,
some of the segments at the front end of the body are modified by fusion, and in
other ways, to form a head, which is furnished with eyes, and bears, in addition to
the jaws, appendages that have been transformed into long, many -jointed feelers,
called antennae. In the lobster, however, there are two pairs of these organs, while
in the centipede there is but one.

These external resemblances are correlated with others connected with the
internal anatomy. The alimentary canal, for instance, traverses the body from
end to end ; and the nerve-chord lying beneath it consists of two adjacent strands
united together in the separate segments, the points of union being marked by
swellings called ganglia, from which nerve-threads radiate to the neighbouring
parts. Above the alimentary canal comes the heart, and this organ, although
superficially very different in the two types, is yet constructed upon the same
general plan. In the centipede it is long, tubular, and composed of many distinct
segmentally-arranged chambers, and furnished with arteries for the distribution of
blood to the tissues, and with slits or ostia by which the fluid again makes its
way back to that organ. In the lobster, on the contrary, the heart is short, thick,
and consists of a single chamber, but is nevertheless provided with the arteries
and slits as in the case of the centipede.

The dissection of these two creatures would, however, reveal one fundamental
difference between them. In the centipede it would be noticed that the body is sup-
plied internally with a rich system of branching tubes which open on the exterior
by means of apertures placed in the sides of the segments. These tubes are known
as tracheal, and their apertures as stigmata. They, or similar structures, are found
in nearly all Arthropods that live upon the land and breathe the oxygen in the
air. They are, in fact, the breathing organs, and analogous to the lungs. The
lobster has no such system of tubes; for living in the water, and breathing
the oxygen dissolved therein, this crustacean has need of a different type of
respiratory organ analogous to the gills of fishes. These it possesses in the form of
delicate plumes attached to the bases of the walking-legs and the sides of the
body just above them ; and although concealed from view and protected from
injury by a large plate, these gills are yet freely exposed to the water in
which the animal spends its existence. Gills resembling those of the lobster in
function, and also substantially in structure, are found in almost all Arthropods that
live in the sea.

The characters that have been here briefly alluded to in the description of the

GENERAL CHARACTERISTICS. 5

anatomy of the centipede and lobster will be found to be equally discernible, if
other prominent types of Arthropoda be examined. Differences of course will be
found to exist ; but, on the whole, the plan of structure that has been sketched is true
for all the classes. For instance, in all of them, except the Centipedes and Millipedes,
there is a tendency in the more specialised members towards an increase in size of
the limbs in the front half of the body, accompanied by a corresponding dwindling
of those in the hinder part. Thus a crab and a spider walk upon four pairs of
legs placed just behind the head, and an insect upon three ; and in the case of the
insect the legs of the hinder region have entirely disappeared, while the larger
number of them have similarly vanished in the spider and the crab. There is also
a tendency in the higher members of each class for the ganglia of the nervous
chord to lose their segmental arrangement, and to become concentrated together in
one large mass, placed near the seat of the greatest muscular activity. Never-
theless, underlying all the modifications of structure — however extensive these may
be — there is a common plan of organisation which may be regarded as typical of
the Arthropoda. This may be briefly sketched as follows. The long bilaterally-
symmetrical body is divided into a series of approximately similar segments, each
bearing a pair of similar and segmented limbs. These limbs are the organs of
locomotion ; but some of those at the front end of the body, where comes the
mouth and the organs of vision, take on the function of jaws, and are used for seizing
and masticating food instead of for progression. The nervous system consists of a
double ventral chord with ganglionic enlargements in each segment, and the first
ganglia of this ventral chain are connected by means of a chord on each side of
the oesophagus with the brain, which is lodged in the head. The heart, lying
above the alimentary canal — which runs from one end of the body to the other —
consists of a series of chambers, one for each segment of the body, and is provided
with arteries for the distribution of the blood, and with slits or ostia for receiving-
it back again.

The Arthropoda are divided into the following classes, the chief characteristics
of which are described further on — (1) Insects (Insecta, or Hexapoda); (2) Centi-
pedes (Chilopoda) ; (3) Millipedes (Diplopoda) ; (4) Spiders, Scorpions, Ticks, etc.
(Arachnida) ; (5) King-crabs (Gigantostraca) ; (6) Crustaceans (Crustacea) ; (7) Pro-
totracheata (Peripatus).

It is possible, however, to group these into larger divisions. The insects,
centipedes, and millipedes, for example, may be placed together as Tracheata,
characterised by the possession of tracheae and of a single pair of antennae. The
Crustacea stand alone in having two pairs of antennae, and in breathing with
gills. By means, however, of the extinct class of the Trilobites, they are
connected with the king-crabs; and these in possessing only six pairs of well-
developed anterior limbs, and in having no antennae, strikingly resemble the
Arachnida. Peripatus is very peculiar, but shows signs of a distant relationship
with the centipedes, although in many anatomical features it is not very far
removed from the worms.

Distinctive The term insect, although originally and, according to the mean-

Characteristics ing of the word, correctly employed in a wide sense to embrace
of insects. aj j ^hose animals in which the body is externally divided into a

6 INSECTS.

number of segments, including, of course, butterflies, beetles, bugs, spiders,
scorpions, centipedes, millipedes, not to mention crabs and shrimps, is now, by
common consent, used in a much more restricted sense to apply solely to such
members of the Arthropoda as have only six walking-legs. In allusion to this
feature the class is nowadays often called the Hexapoda, the term being much
more precise and applicable than that of Insecta. In addition, however, to the
possession of six legs, insects are characterised by certain other well-marked
features, serving to distinguish them from all other arthropods. The body is
divided into three distinct regions, arranged in a longitudinal series, and named
respectively, from before backwards, the head, thorax, and abdomen.

The head, which varies much in size and shape in different groups, bears the
eyes, the antennae, and the jaws. The eyes are of two kinds, simple and compound.
The latter, of which there is a single pair, situated one on each side of the head,
and often so large as to occupy the greater part of its right and left half, consist
externally of a multitude of lenses, often exceeding many thousands in number.
The simple eyes, or ocelli, on the other hand, are fewer in number — usually only
two or three — and placed upon the forepart of the head. The antennae are movably
articulated by means of a special socket to the front of the head, usually below or
near the inner edge of the compound eyes. They vary much in structure and
length, being sometimes long and pliable, and composed of a large number of
segments, as in the cockroach, and at other times short, like those of the house-fly,
and consisting of a few 'segments only. There is no doubt that the antennae
contain highly important organs of sense, the bristles with which they are studded
being probably tactile, and some of the other organs possibly olfactory in function.

The front edge of the head, or its lower edge when carried vertically, is often
movably jointed to the rest of it, and constitutes an upper lip, or labrum. In the
formation of the jaws, which are attached to the lower surface of the head, three
pairs of appendages, respectively named the mandibles, the maxillae, and the
labium, are involved. But these parts are susceptible of an extreme amount of
variation in structure and function, being sometimes formed for mastication, as in
the mandibulate forms, such as the cockroaches and beetles, and sometimes for
piercing or sucking, or both combined, as in the so-called sucking forms like
the flies, butterflies, and bugs. There is no doubt that the mandibulate type of
mouth in which the gnathites, or jaws, are more foot-like in structure, is the most
primitive of all. In this case the mandibles usually consist of a stout pair of one-
jointed skeletal pieces, the inner edge of which is furnished with biting teeth.
Sometimes, as in the males of stag-beetles, the mandibles are enormously large,
and simulate horns. The maxillae are much more complicated in structure ; each
consists of a basal piece, composed of two segments — the cardo and stipes — from
which spring two branches, an outer or palp, which has the appearance of a
dwarfed limb, and an inner, which is in its turn double, the inner blade being called
the lacinia, and the outer the galea. The jaws of the third pair, constituting the
so called labium, or lower lip, are constructed upon the same principle as the
maxillae, but the parts usually considered to correspond to the cardo are united
to form a plate — the mentum — which is articulated by its hinder part to a sternal
plate of the head, called the submentum. In front of the mentum there are

GENERAL CHARACTERISTICS. 7

externally the jointed palpi, resembling those of the maxillae, and between these
there is a median, sometimes bilobed, piece, called the ligula, and a pair of pieces
termed the paraglossae. The degree of development of the several parts varies
greatly in different orders, and it is often a matter of considerable difficulty to
determine the exact correspondence that exists between them in two insects
belonging to different orders. This is especially the case when the jaws have
been modified to form the different organs of suction that are met with. The
structure of these will be described in detail when the species that possess them
are discussed. Another organ to be mentioned in connection with the jaws is a

MOUTH-ORGANS OF INSECTS.

1, Head of honey-bee, from the front ; 2, Head of humble-bee, from below ; 3, Maxillae and labrum of a bee
(Andrena) ; 4, Maxillae and labium of saw-fly (Cimbex) ; 5, Lower view of head of carnivorous beetle
{Procrustes) ; 6, Maxilla of carnivorous beetle (Cicindela) ; 7, Maxilla of cock-tail beetle (Staphylinus) ; 8,
Maxilla of locust ; 9, Head of bug {Cicada) from the front ; 10, Head of butterfly ; 11, Head of horse-fly
{Tachina).
Labium — a, mentum ; b, ligula ; b', paraglossae ; c, palp ; d, mandible. Maxilla (e), with/cardo ; g, stipes ;
h, lacinia ; h', galea ; i, palp ; k, head-plate ; n, teeth on lacinia.

membranous lobe, called the hypopharynx, or tongue, projecting into the interior
of the mouth from the floor of the labium.

The thorax, or median part of the insect's body, is formed of three segments
called the pro- meso- and metathorax, each of which is composed of several distinct
pieces. The dorsal areas of the three segments are termed the pronotum, meso-
notum, and metanotum ; the lateral regions the pleurae ; and the inferior regions
the sterna. To the pleurae are articulated the three pairs of legs, each of which
consists primarily of five segments, named respectively, from the base to the apex,
coxa, trochanter, femur, tibia, and tarsus; the last, which constitutes the foot, being
generally tipped with two claws, and subdivided into several — often as many as
five — smaller segments. To the sides of the upper surface of both the meso-

8 INSECTS.

and metathorax are usually attached a pair of wings, which are very characteristic
organs of all the higher insects, although absent in the lowest forms, and in many
species degenerate through parasitic habits. The wings differ much in structure,
thickness, clothing, etc., in different orders of insects, but in all cases they seem
to consist of an upper and a lower membranous layer, traversed by narrow bands
of thicker material, the nervures.

The abdomen in insects is marked off from the thorax by the absence of true
appendages. It may consist of as many as ten distinct segments, but never of
more, and generally of fewer. Each segment is protected above by a dorsal plate,
or tergum, and below by a ventral plate, or sternum, the two being connected
laterally by membrane. The last segment is often provided with a pair of
appendicular structures, which may be long, many-jointed, and antenniform, or
short and one-jointed, like the pincers of an earwig. And, in addition to these,
certain other structures, such as the stings of bees and wasps, and the ovipositors
of locusts and ichneumon flies, are frequently connected with the hinder segments
of the abdomen. The only other external structures that need be mentioned here
are the stigmata, or apertures, of the respiratory organs. These pierce the lateral
surfaces of the thoracic and abdominal segments, and vary much in number, size,
and form, being generally far more plainly seen in the larvae than in the adults.
There may be as many as eleven pairs, but usually the number falls short of this.

In exceptional cases, as in the plant-lice (Aphidce) belonging to the order
Hemiptera, and in certain parasitic flies of the group Pupipara, the young are born
in an advanced stage of development, the eggs developing within the body of the
parent without being first deposited. But in the vast majority of species the
young make their first appearance in the world in the egg-stage.

Between the time of its escape from the egg-shell and the attainment of
maturity, the young undergoes a succession of moults, or castings of the skin. In
some cases the change of structure that an insect presents during the course of its
growth is, comparatively speaking, trifling, the young being hatched in a condition
in which in outward form it substantially resembles the parent in everything but
size, and, in the case of species that bear wings in the adult, in the entire absence
of these organs. A familiar instance of this method of growth is found in the
cockroaches and grasshoppers, in which the young emerge from the egg as
miniature and wingless copies of their parents.

In other cases, however, as in the flies (Diptera) and butterflies (Lepidoptera),
an extraordinary change of form takes place during growth, the young upon
hatching being so totally unlike the adult that no one unacquainted with the facts
of insect development would suppose the two to belong to the same category of
animals. In these two orders, as well as in some others, the new-born young
has the appearance of a fleshy grub; and the grub-like condition is retained
unchanged, except in size, until the time for the last moult approaches. It then
undergoes a startling change of condition, and, losing its organs of sense and
ceasing to feed, passes into a state of quiescence, during which the final changes
in its organisation are more or less rapidly passed through, and the final moult
sets free the mature insect, perfect in all its structural details.

The immature stages of insects that present a complicated development of

GEOLOGICAL AGE. 9

this kind are variously spoken of as grubs, maggots, caterpillars, or, more com-
prehensively, larvae; while the quiescent stage is termed the chrysalis or pupa,
and the final sexually mature stage the imago or perfect insect. Moreover, such
species are said to undergo a complete metamorphosis, or to be holometabolous, as
opposed to those like the cockroach, whose growth is accompanied by but little
change of form, and are said to present an incomplete metamorphosis or to be
ametabolous. It must not, however, be supposed that all insects are either com-
pletely or incompletely metamorphic in their development. The familiar types
that we have mentioned exhibit almost, although not quite, the extremes of change
that are offered in the class; but between these occur other types which show
developmental phenomena more or less intermediate in their nature, being less
complicated than those of the blow-fly and more complicated than those of the
cockroach. An account of these various methods of development will be given
under each order as it is described.

Like the Crustacea, Arachnida, Millipedes, and all the main
' divisions of the Arthropoda, with the exception of the Proto-
tracheata (Peripatus), and possibly the Centipedes, Insects are an exceedingly
ancient group, having left their remains in strata of Silurian age. The exact
nature and affinities of these primeval remains has not, however, yet been satis-
factorily determined, and some authors indeed seem to doubt whether they are
rightly referred to insects. Still there is no question that species of this
group flourished in abundance during the Carboniferous period ; but the con-
clusion that all the known fossil insects from these strata form a natural order,
distinct from all the existing groups of this rank can hardly be regarded as finally
established, seeing that, in the opinion of some authors, they are assignable to
places in our classification of existing species, and are nearly related to the orders
Orthoptera (cockroaches, grasshoppers, and dragon-flies), and Hemiptera (bugs and
plant-lice). In the Secondary rocks insect remains, considering the small chances
of the preservation of such creatures in stratified deposits are fairly abundant ;
and none of the species present ordinal differences from those which now exist.
So, too, the hosts of species that have been discovered in Tertiary deposits, in the
amber-beds and elsewhere, are referable to existing orders.

It has been estimated that in numbers of species insects excel
' all other land animals of the world taken together, and a recent
computation has put the total of described forms at 250,000, and yet, according to
Lord Walsingham, only about ten per cent, of existing species have hitherto been
discovered. But this is not the only respect in which the animals of this class
are in advance of all other groups. In brightness of colour, beauty of pattern,
and gracefulness of form some of the species can hardly be equalled even by the most
gorgeous birds, while in mechanical perfection of structure, as testified by activity
and strength, others of the group are unsurpassed in the animal kingdom. It has
been stated that if a man could leap in proportion to his stature as far as a flea can
hop, he could clear at a bound a wall over one hundred feet high, and if he could sing
as loudly as the cicada, his voice could be heard for a distance of many miles.
Indeed, even in matters about which man is wont to especially pride himself,
such as those touching social organisation, he might with advantage go to the ant

io INSECTS.

to learn wisdom, since many of the problems of modern civilisation, involved in
the questions concerned in the regulation of increase of population, the proper
division of labour, and the support of useless individuals, have been satisfactorily
solved by many of the species of insects that live habitually in communities.

Speaking in a general way, insects may be said to be terrestrial animals, since
all the species are fitted more or less completely for atmospheric respiration and for
progression on the land ; many of them in addition are furnished with wings, which
propel them through the air with amazing velocity. In many of the orders, how-
ever, as, for instance, in the beetles and bugs, there are species that have adopted
an aquatic mode of life and spend their days in fresh- water ponds and streams in
various quarters of the globe. Others again, like some of the gnats and dragon-
flies, live in fresh-water during the larval stages of their existence, but quit it on
attaining maturity. Insects, too, are sometimes found on the coast beneath stones
and seaweed at low water, but there is only one species of insect that can strictly
be called marine ; this is a bug (Halobates) sometimes met with in numbers on
the surface of the ocean thousands of miles from land.

The phenomena known as mimicry and protective resemblance
Mimicry. . ... .

are strikingly exemplified in insect life. The term mimicry is usually

applied to cases where a species, otherwise unprotected, lives unmolested owing to
its resemblance to another which is gifted with defensive weapons in the form of
poison-glands, or with a nauseating flavour that renders it distasteful. Such species
as these are usually rendered conspicuous by contrasting patches of bright colour.
It is noticeable, for instance, that the patterns of bees and wasps are strikingly
diversified, in order that the insects may be readily recognised and not slain by
mistake for other species. Bees and wasps, then, being species that enjoy
immunity from attack, are often imitated or mimicked by perfectly harmless flies
and moths, and some beetles and animals allied to crickets similarly mimic ants.
But the phenomenon of protective resemblance — or the mimicry of inanimate
objects — by which a species is rendered practically invisible amongst its surround-
ings on account of its resemblance to a leaf, stone, twig, or bird-dropping, is of far
commoner occurrence. On the accompanying Plate a few instances of this kind
of adaptation to surroundings are portrayed. Figs. 12, 13, and 18 are the
larvae or caterpillars of different species of Lepidoptera, the first two in colour and
shape simulating branches, and the last a snail-shell; Figs. 1, 2, 9 and 14 are
leaf-like pupae or chrysalids of other kinds of Lepidoptera; while Figs. 3, 5, 7, 11,
15, 23, and 24 are the adult stages of members of the same order under different
disguises. The most noticeable of these is Fig. 11, representing a large and
handsome butterfly, which, when at rest with its wings folded back, exactly
resembles a dead leaf, even to the midrib and stem ; while Figs. 23 and 24, exhibit
two small moths, which might be readily mistaken for bird-dung. In the
Orthoptera, as the insects allied to the cockroaches and grasshoppers are called,
the phenomenon is carried to an extent elsewhere unsurpassed in the animal
kingdom. This is well shown in the case of the leaf-insect (Fig. 4), the stick-
insect (Fig. 8), and the leaf-like locust (Fig. 10). Most of the other figures on
the Plate are of less importance. Attention, however, may be drawn to the water-
bug (Fig. 16), the young dragon-fly (Fig. 6), the beetle (Fig. 19), the curious bugs

I. Chrysalis of Apatura ilia. 2. Chrysalis of Rhodocera rhamni. 3. Green Hairstreak Butterfly, Thecla rubt. 4. Leaf Insect,
Phyllium sicti folium. 5. Green Silver Lines Moth, H alias prasinana. 6. Young Dragon-Fly. 7. Scarce Merveil in Jour Moth,
Moma orion. 8. Stick Inseet, Bacillus rossii. 9. Chrysalis of Papilio podahrius. 10. Leaf-like Locust, Pterochroza cnlorata.

II. Dead-leaf Butterfly, Kallima philarckus. 12. Caterpillar of Araptrryx sambucaria. 18. Caterpillar of Notodonta ziczac.

14> Chrysalis of Pabilio evander. 15. Buff-tip Moth, Phalera bucephala. 16. Water-Bug, Ranatra linearis. 17. Dead-leaf May-Fly,
Drepanopteryx phatanoides. 18. Larva of Ctmbex bctulce. 19. Mesosa cerculionoides. 20. Phlcea corticata. 21. Pemphigus xylostei.
22. Psychid caterpillar. 28. Tortrix ocellaria. 24. Clouded Border Moth, A braxas marginata 25. Histerid Beetle. 26. Byrrhid
Boetle. 27. Cocoon of A ides amanda.

■

MIMICRY IN INSECTS.

HYMENOPTERA. 1 1

(Fig. 20) which in attitude and colour closely approximate to the stems or bark
to whick they cling. Figs. 25 and 26 show two beetles resembling sheep's droppings.
Fig. 17 exhibits one of the May-flies like a dead leaf, and Fig. 21 two plant- bugs
which secrete threads of white wax and appear as tufts of woollen matter.

Characteristics 1'ne general characters of the Hymenoptera will be more or less

of the familiar to most readers from their acquaintance with the well-

Hymenoptera. known members of the wasp, bee, and ant tribes. The scientific
name by which the order is known is derived from the fact that the upper and
under wings on either side are linked to each other by a series of minute hooks on
the one which cling to a fold in the membrane of the adjacent margin of the other.
The group includes the saw-flies, wood-borers, gall and parasitic wasps, ichneumons,
ants, spider-killing wasps, solitary and social wasps, and solitary and social bees.
The number of species known is from 30,000 to 40,000, though from our know-
ledge of the proportion which they bear to other orders, it is computed that there
may be upwards of 150,000 species yet to be discovered. In specialisation of
structure they undoubtedly rank amongst the most highly developed of the
Insecta. The neat, agile frame, hard shining integuments, stout mandibles, strong,
light wings, and movable abdomen, bearing, in the case of the female, at its apex
an ovipositor of great power and precision of application, or modified into an instru-
ment for sawing and boring in some species, and in several families becoming a sting.
All these features combine with a temperament of extreme nervous energy to give
them a character for general intelligence, and a power of adapting means to ends
such as are manifested in no other allied order. The web-making spiders alone
resemble them in this respect, and we are able to find few analogies nearer than
the intelligent action, individual or concerted, of man himself. The social
Hymenoptera, such as ants, bees, and wasps have solved, on their own life-plane,
industrial difficulties and social problems, pressing for solution in the various
societies of men. Doubtless this has been accomplished to a certain extent
only at the cost of a loss of individuality such as civilised man would not
tolerate for a moment. When we find that the worker-ants, bees, and wasps
have, during their specialisation as workers pure and simple, lost their sexual
faculties, that the members of a species of Amazon ant during their specialisation
as warriors have lost the power of even feeding themselves, being entirely depend-
ent on slaves for their food, we may well pause before concluding that such
solutions of important problems are in the end for the best, at any rate so far
as concerns the human race.

Without entering into the more minute details of structure, the general
characters by which the order may bfe distinguished are as follows. The posses-
sion of four transparent wings, a head, thorax, and abdomen distinct from each
other, the latter joined to the thorax by a narrow stalk, or, in the case of the
Tenthredinidce by a broad uniting joint. The integuments are strong, hard,
shiny, and often hairy. The mandibles are well developed for biting purposes,
while the subordinate mouth-parts are, in the case of the honey-bees, modified to
form a long tongue-like proboscis for extracting nectar from flowers. The head
is more or less globular, bearing compound eyes and several ocelli on the crown
between and just behind the antennae. The mandibles are used, besides the

12 INSECTS.

mastication of food, for digging holes in the ground or for gnawing timber and
various other purposes. In some ants the soldiers have the head enormously
developed, as are also the mandibles ; their function being to protect the society
from enemies, and also to carry on war against neighbouring communities. The
antennae are in most cases long, jointed, and filiform, constituting sensitive organs of
touch and recognition. The thorax is composed of the usual three pieces,
prothorax, mesothorax, and metathorax. It bears the wings, four in number,
above, and the legs, six in number, beneath, the latter being modified in many
species for special purposes, such as, in the bees, for gathering pollen from the
blossoms of the plants visited for the sake of honey. Often the legs are armed with
long spines, which in the sand-wasps materially assist in the excavation of the
pits in which these insects bury their victims and deposit their eggs. The wings
are ample, strong, and light, formed of a transparent membrane strengthened
with fine nervures or veins. The arrangement of these nervures varies much
in different groups, and is of importance in the classification of members of the
order. The relative importance of this character is, however, not the same in
every family, being in the saw-flies, perhaps, of the greatest value. Species which
are wingless in one or both sexes are found in many of the families ; while in the
genus Oxyura of the family Proctotrypidw the wings consist merely of a fine
central stalk with a battledore-shaped plumose tip. The abdomen is united to the
metathorax either throughout its whole width, as in the Tenthredinidce, or, as in
most of the other families, by a narrow stalk or petiole. These two characters
serve for the division of the order into the groups of Sessiliventres and Petiolata.
The organs of reproduction are situated at the apex of the abdomen ; while in the
female the instrument for depositing the eggs has become in the section Aculeata
developed into a sting ; in the Ichneumonidce it is sometimes enormously long, and
used for piercing the larvae in which they lay their eggs. In the case of the large
wood-borers (Sirex) it is used as a boring instrument, while in the saw-flies it is
serrated on the edges and employed to wound the tender shoots on which the
eggs are deposited. Amongst the Pompilidce and some other families, the sting
is used to paralyse the victim in which the insects lay their eggs, or leave in the
cell to feed the larvae as they hatch. Probably no pain is given to the victim,
and even in the case of those grubs that feed internally upon the tissues of
caterpillars in all probability less inconvenience is caused than we suppose.

In all cases the metamorphosis is complete. The egg may be laid in a cell
prepared either by the female or the workers for the purpose, and the grub is fed
by the attendants on a preparation of pollen or other foods specially prepared.
In other cases the eggs may be laid on the foliage of trees and plants on which
the larvae feed, or they may be deposited upon or in the bodies of living or
paralysed caterpillars, grubs of other species, or spiders, locusts, and the like.
The Cynipidce with the poison from their sting, and other causes combined,
produce a large gall upon the leaves of trees, especially oaks ; and on the fleshy
cell-structure of these galls the grubs feed when they emerge. Larvae of two
different kinds are met with in the order. Thus, whereas those of the saw-flies
have legs, sometimes even more in number than those of the Lepidoptera, the
grubs of the majority lack functional legs. The former live a life of greater

HYMENOPTERA. 13

liberty, feeding on the foliage of trees ; the latter are free, so far as they are not

confined within an egg-membrane, but being internal feeders, whether in foliage

larvae, wood, or shut up as solitary hermits, each in its several cell passes a larval

period of limited freedom. It is a curious fact that the legs of some larvae are

more evident in an early than in the latter stages, thus proving that the habit of

cell-life is a comparatively recent departure from a former habit, when in all

probability the larval life was passed in greater freedom.

The phenomenon of parthenogenesis is one which crops up in
Development. . , . . .

various orders of insects, being simply the production by the female

of eggs or young without the fertilisation of the egg-germs within the female, by
the stimulative elements necessary to the production of young in the higher
animals. It is not, however, a chance phenomenon, appearing as a race-preserving
expedient, on the sudden failure of male forms, but one of nature's resources for
preserving the continuity of species. It is constant in many species of the
Hymenoptera, in the form of what is known as the alternation of generations ; in
some species, however, it is supposed to be the sole form of reproduction, for the
males of these species have never yet been discovered. Whether we regard
the fertilisation of the female egg-germs by the male elements as dynamic or
stimulative, or as merely a matter of the interchange of character determinants
between the two sexes, it appears to be beyond a doubt that a continuous
succession of virgin-reproductions must inevitably tend to the degeneration and
ultimate extinction of the race. Parthenogenesis or virgin-reproduction may
be of three kinds. First, resulting in the production of the male sex only ;
second, of the female alone ; and thirdly, in cases when the young are produced
not as eggs in the first instance, but alive, as in the case of the plant-lice or
Aphidce. It seems that parthenogenesis does not favour the production of one
sex more than another. We should, therefore, be cautious how we accept too
hastily the commonly received belief that male bees are necessarily the offspring
of non-fertilised eggs. It by no means follow^ that because an egg was not
fertilised that therefore the sex produced in it is the direct result of non-
fertilisation. The question, however, is still a matter of controversy, and more
evidence is needed before final conclusions can be reached.

That the members of this order are on the whole useful to man cannot be
doubted, — more useful perhaps than the majority of insect forms, — whether as bees,
with their honey-storing instincts, or as the ichneumon tribes dealing destruction
to thousands of the larvae — those insect pests which would otherwise work terrible
havoc with our corn crops and garden produce. On the other hand, it must be
confessed that the larvae of the saw-flies often work damage to the foliage of
forest-trees, while in many tropical climates ants are a devouring scourge to all
that belongs to man.

We must now leave these introductory lines, but before passing
Classification. , ,,.,,, . ,. „ . . . , ., .

on to a more or less detailed description of certain species and their

peculiar characteristics of structure and of habit, the subjoined outline of classifica-
tion of the various families of the order will give a general idea of the different
groups, which are more obviously separated by certain broad distinguishing
characters.

14

INSECTS.

Order Hymexoptera.

Suborder Sessili ventres.

1. Family Texthredixid^e — Saw-Flies.

2. „ Siricid^e — Wood-Borers.
Suborder Petiolata.

Section Parasitica.

1. Family Cyxipid^e — Gall- Wasps.

2. „ Proctotrypid^: — Egg- Wasps.

3. „ Chalcidid^: — Parasitic Gall- Wasps.

4. „ Ichxeumoxid^e — Large Larvae- Wasps.

5. „ Bracoxid^e — Small Larvas-Wasps.

6. „ Evaxiid^e — Hymenoptera Parasites.

7. „ Chrysidid^e — Burnished Wasps.
Section Aculeata.

1. Family Formicid^e —Social Ants.

2.

3.

4.

5.

6.

7.

8.

9.
10.
11.
12.
13.
14.
15.
16.
17.

Mutillid^e — Parasitic Ants.
Thyxxid^e — „ „

scoliid.e — ,, „

Sapygid^e — „ „

Bembicid^: — „ „

Pompilid^e — Spider- Wasps.
Sphegid^e — Locust- Wasps.
Larrid^e.
Nyssoxid^.

Crabroxid^e — Fly and Aphid- Wasps.
Philaxthid^e — Andrena Parasites.
Masarid^e — Solitary Wasps.
Eumexid^e— Mud- Wasps.
Vespid^e — Paper- Wasps.
Andrexid^e — Solitary Bees.
Apil\e — Honey and Humble-Bees.

The Saw-Fly Group, — Suborder Sessiliventres.

This group contains the various species of saw-flies, and may be subdivided
into the saw-flies proper (Tenthredinidce) and the wood-borers, or tailed-wasps
(Siricidce), although it also comprises the little pith-boring Cephidce and the rare
and little known species of Oryssidce. The food of the larvae of these insects
consists entirely of vegetable matter. In the case of the first-named family, the
leaves of trees and shrubs ; in that of the second, the solid wood of various trees ;
and in the case of the third, the tender pith of the stalks of rye and also the
shoots of pear and other trees. Such grubs as are internal feeders are either
limbless, or have at most six more or less rudimental thoracic legs. Those, on the
other hand, which live a free life and feed on foliage, are very similar in general
appearance to lepidopterous larvse, from which they may be distinguished by the

HYMENOPTERA.

*5

greater number of their legs ; these varying from twenty to twenty-two, whereas
those of the Lepidoptera have but sixteen at most. They also differ by the shining
and almost naked skin, and the curious habit possessed by many of curling in the
posterior segments, raising them at the same time and depressing them with a
rhythmic movement. This action, which may be for the purpose of frightening
away foes, coupled with the melancholy -looking eyes, gives them a grotesque
appearance, not observable in the caterpillars of the Lepidoptera, save in a few
instances. When full grown, the majority of the larvae leave the food-plant and
spin in or on the surface of the ground, or under dry leaves and moss, a barrel-
shaped cocoon in which they pass the winter, turning to a chrysalis only a short

1, Sirex juvencus, female larva, pupa (all of nat. size) ; 2, corn saw-fly and larvae in the rye stalks ;
3, Pachymerus calcitrator, a wasp parasitic on the above ; 4, Larva and pupa of Cephus (enlarged).

time before the perfect insect emerges. At least a thousand species are known,
though this is probably but a small moiety of those that exist.

Stem Saw-Flies, — Family Cephid^e.

The larvae of these slender, delicate, armoured insects pass their lives in the
stems of plants or young shoots of trees ; and the adults are characterised by the saw
of the female being partially concealed by two integumental flaps. As an example
of the typical genus, we may take the corn saw-fly (Cephus pygmceus), of which
the perfect insect flies actively in the sunshine, flitting from blossom to blossom
among buttercups in May, and thence onwards through the summer. The larvae
cause serious damage on the Continent to rye crops, and more rarely in wheat fields,
where they crawl up and down within the stems, feeding on the delicate tissues.
When full fed, they construct a transparent cocoon in which to pass the winter,

i6

INSECTS.

becoming pupae, and a little later in May emerging as full-grown saw-flies. The
parasitic insect {Pachymerus calcitrator) figured in the illustration on p. 15 is one of
the Petiolate Hymenoptera which seems to be exclusively parasitic on the present
species.

Tailed Wasps, — Family Siricid^e.

In this family the female is furnished with a long, boring ovipositor for
piercing the bark of trees ; the eggs being laid in the orifice thus formed, and the
larvae feeding on the wood. In the accompanying illustration of the boring
apparatus of one species c, c, a, shows the whole of the muscular structure with

which the boring is carried out. The perfect insects are
usually of large size and conspicuously coloured. Among
the typical forms the common tailed-wasp (Sirex juvencus)
is a very rare species in England, although more plentiful
on the Continent. The females, which are sometimes
surprised in the act of depositing their eggs on pine-trees,
may be easily caught, as the ovipositor can only be with-
drawn with considerable difficulty. Indeed, the abdomen
breaks in half, if the insect be roughly grasped. The much
larger giant tailed-wasp (S. gigas) is far commoner among
pine-trees, and is distinguished by its bands of black and
yellow. Although it does considerable damage, it does not
attack a perfectly healthy tree, unless recently felled. How
long the larvae may live in the interior of the tree, and
how long it is before the perfect insect appears, is not
known, but cases are often quoted of this insect appearing
in houses soon after their completion, having evidently
emerged from the wood of the joists and beams. Another
genus is well represented by the broad -bodied saw-fly
(Lyda campestris). In this species the grubs feed on the
young shoots of the Scotch fir, in which the eggs are laid.
When hatched, the larvae spin a slight web in which they
remain concealed, protruding the forepart of the body
when feeding on the pine needles. When all the needles in the neighbourhood
have been devoured, the web is extended, so that a great number of young shoots
may be embraced and destroyed. The perfect insect is shining blue-black, with
some of the abdominal segments reddish yellow.

BORING APPARATUS OF GIANT

tailed wasp (much en
larged).

True Saw-Flies— Family Tenthredinid^:.

In this exceedingly numerous and widely distributed group, a well known
example is the pine saw-fly (Lophyrus pini), of which the larvae are sometimes
found in such numbers in pine-woods, where they feed upon the needles, that the
trunks are often coloured yellow and the branches weighed down. Towards
the end of July, the perfect insect emerges by gnawing off the cap of the barrel-
shaped pupa-case. The eggs are laid in incisions made in the needles, these

HYMENOPTERA.

17

wounds being subsequently closed with a viscid secretion which protects the eggs.
As many as twenty eggs may thus be deposited in a single needle. When young,
and also just before turning into pupa?, the grubs are very susceptible to sudden

FEMALE AND MALE OF GIANT-TAILED WASP (nat. size).

cold or heavy rain, which will kill off thousands. In addition to these destructive
agencies, nearly forty different kinds of parasites infest the grubs, while mice
devour numbers of the pupae. The illustration below shows all the stages of de-

1, pine saw-fly, larvae on pine needles, and also pupse cases shut and open ; 2, broad-bodied saw-fly,

with larvae and nest. (All nat. size. )

velopment, one of the grubs being drawn in the act of endeavouring to ward off the
attacks of a parasite by the ejection from its mouth of an offensive fluid. To the
same family belongs the turnip saw-fly (Athalia spinarum), which is one of the
vol. vi. — 2

i8

INSECTS.

most destructive species. The perfect insect appears in May from larvae which
have passed the winter in their pupae cases, and lays its eggs upon the leaves of
rape and turnips ; as many as two hundred or three hundred eggs being often
deposited by a single female ; and in September and October the ravages of the
green and black larvae become only too evident. The grub is full grown in October,
when it descends to the surface of the earth, and forms a cell of earth grains, in
which it passes the winter. The majority of the members of the family belong to
the typical genus Tenthredo, and are elegant, active insects, which alone of all the
saw-flies exhibit a carnivorous habit. It is not easy to distinguish the males from
the females, though the difference in the colour is of some assistance. It has been
noticed, for instance, that in cases where the abdomen of the female is entirely
black, that of the male is black and red. Of the green saw-fly (T. scalaris), the
larva is common on the willow, and is pale green with black spots on the back,
sometimes blending to form a central band. The pretty brush-horned rose saw-

1, turnip saw-ply and larvae ; 2, rose saw-fly, male ; 3, saw-fly, female, and with larvae. (Nat. size.)

fly (Hylotoma rosea), which in size and colour closely resembles the turnip saw-fly,
extends throughout Europe, where it is common wherever rose-trees occur; the
larva being found from July to October on both the wild and cultivated roses.
When turning to a pupa, it spins an outer meshed envelope, and a more densely
woven inner one ; early larvae pupating at once, and emerging as perfect insects
early in August. The later broods, however, pass the winter in the pupa case, and
appear in the following spring. The female makes an incision on the twigs of rose
bushes, in which she lays her eggs, after which the twig withers away.

Typical Group — Suborder Petiolata.

The insects belonging to this second subdivision of the order are distinguish-
able from the last by the petiole, or short stalk joining the abdomen to the thorax.
Sometimes this stalk is so short that the abdomen and thorax are closely united,
while in others it is longer, and thus these characters form a fairly natural sub-
division of the Petiolata into the pseudosessile and pedicellate forms. For general

H YMENOPTERA.

19

purposes they may, however, be divided into Parasitica, or those in which the
females are furnished with an ovipositor, and Aculeata, or those in which the
ovipositor has become modified into a retractile sting.

Gall- Wasps, — Family Gynipid^.

Of the former, or parasitic section of the suborder, our first representatives are
the gall-wasps {Cynipidce), all of which are small and inconspicuous insects, vary-
ing in colour from black to brown and brownish red. The wings are furnished
with few nervures, and the dark stigma on the anterior margin is absent ; while
in some species the females have the wings either rudimentary or altogether want-
ing. Of the galls so common on the foliage of trees and other plants, some are
produced by beetles, aphides, flies (gall-midges), and others by the members of
the present family and some of the Tenthredinidce. In the gall - wasps each
species selects some special portion of the plant for its attack, which it pierces with

green saw-fly, Tenthredo scalaris (nat. size).

its ovipositor, and lays an egg in the wound. As to what exactly gives rise to the
resultant gall, which follows sooner or later upon the wounded plant, is not known
with any certainty. It has hitherto been supposed that the fly injects an irritat-
ing fluid into the wound, but recent researches tend to show that this serves rather
as an adhesive security to retain the egg on the selected spot. It is probable that
the different stimulative irritants offered, first by the inflicted wound, next by the
presence of the eggs, and thirdly by the movements of the larva after it is hatched,
together with the action of a fluid exuded by the grub itself, all tend to produce
the strange modifications of cell structure which manifest themselves in the forms
of the various kinds of galls. The larvae of the Cynipidce almost entirely feed
internally upon galls produced on oak-leaves and the oak-blossoms. These galls
are entirely closed, and the grub dwells within a hard cell, called the larval
chamber. In some cases there may be several such chambers, as, for instance, in
the Bedeguar-gall on the wild rose-tree formed by Rhodites rosce. We have said
that each species confines itself to one portion of the plant, and the form of the
gall is the same ; but an exception is furnished by the galls of Spathegaster bac-
carum, which occur upon the leaves as well as on the flower-tassels of the oak.

INSECTS.

The phenomenon known as the alternation of generations, — that is to say,
where produced generations alternate with each other in consecutive succession, —

] , common oak-gall wasp ; 2, Torymus reyius, a parasite on the same ; 3, Gall of Cynips gemmce ; 4, Larval
chamber, shut and open ; 5, The same enlarged, above on the left is figured the purple hairstreak and its
larva; 6, The same enlarged ; 7, A gall cut through, showing the grub.

2 6 4

1, the sponge gall-wasp, with an old sponge-gall ; beneath is a new gall, whence the wasps have not yet made their
exit ; 2, oak-root gall- wasp, with its gall ; 3, bramble gall- wasp (Diastrophus rubi), with its gall ; 4, A gall of
the same slit in half; 5, Synergus facialis ; 6, Figites scutellaris, parasites; 7, Ibalia cultellator, parasitic on
Sirex juvencus. (All the galls and Fig. 7 nat. size ; Fig. 6 enlarged.)

HYMENOPTERA.

21

has been clearly shown to exist amongst the Cynipidai. It is a remarkable fact,
too, that the galls produced by a parthenogenetic female are different in form from
those produced by a female originating from the normal sexual process. The
insects produced by these different galls were for many years looked upon as
distinct species. It is, of course, on the cell-tissues of the gall that the larvae of
the Cynipidce feed and thrive ; they themselves, however, in their turn being
subject to the attacks of numerous hymenopterous parasites of various kinds.

Of the typical genus, we may take the common oak-gall wasp (Cynips folii)
as a familiar example. It is a glistening black insect, which forms an oak-gall on
the under side of oak-leaves. A parasite (Torymus
regius) lays its own egg upon the larva of the
Cynips lying within the gall, when the latter is
about half grown. Another species (Cynips gemmce)
is produced from conical scale-covered galls, sprout-
ing from the young shoots of the oak, in the interior
of which the grubs feed. The illustration on p. 20
shows the gall produced by insects of this species.
To the same family belongs the sponge gall-wasp
(Teras terminalis), .which emerges from many-
chambered spongy galls. In spring these galls are
light coloured ; but later on, when the insect has
made its escape, become brown. The female insects
may be either winged or wingless, whereas the males
are always provided with these appendages. Up-
wards of forty parasites have been reared from the
galls of this species. Yet another familiar type is
the bramble gall-wasp (Diastrophus rubi), which in
spring produces hard and often twisted swellings on
bramble -stems, from which in due course emerge
the perfect insects. In the same illustration is
shown the oak - root gall - wasp (Bioriza aptera).
In this form the female is wingless, but the male is
unknown. The galls are formed on the rootlets of
the oak-trees beneath the surface of the ground.

In the common rose-gall wasp (Rhodites rosce), which produces the so-called
bedeguan gall on roses, the larvae are full-fed in autumn, although the perfect insect
does not appear till the following spring. Their beautiful, mossy, pink-tinted galls
furnish a home for many other insects, such as various species of Synergus, but
especially parasites belonging to the families Pteromalidce and Braconidce.
Synergus facialis, of which a figure is given in the lower illustration on p. 20, is
parasitic on the gall-wasps. So too is Figites scutellaris, shown in Fig. 6 of the
same illustration. These are gall-wasps, so far as structure is concerned ; but as
regards their habits they are in no way different from ichneumons, living in the
larval state in the bodies of various insects. Figites scutellaris, as well as most
other members of the group, are parasitic on the larvae of the flies ; while Ibalia
cultellator is parasitic in the larvae of the giant saw-flies.

ROSE GALL-WASP AND ITS GALL.

INSECTS.

Family PROCTOTRYPIB^E.

The members of this obscure family are minute insects, with scarcely a trace of
nervures in the wings in some species ; and the ovipositor can be protruded and

withdrawn at pleasure. Though some of the
species are wholly unlike the Aculeata, yet others
approach them so nearly in general characters that
the present classification must be regarded as
tentative. The habits of these minute insects are
imperfectly known, though some are parasitic in
the eggs of insects and spiders. The perfect insects,
small and black, with variously-shaped plumose
wings, seem to prefer damp, dark localities, such as
furnished beneath fallen leaves and debris of
hedges. Here also may be placed the two species
of egg- wasps (Teleas hvviusculus and T. terebrans),
which are both shining black and very minute
insects, shown in the accompanying illustration,
where they are buzzing round the eggs of a moth,
ready to insert their own. The females usually
deposit their eggs in those of the family Bombycidce,
as, for instance, those of the common lackey.

Familv GhalcibiBjE.

1,

EGG-WASPS.

Teleas Icevlusculus ; 2, Teleas tere-
brans ; 3, Eggs of a moth with a Teleas
upon them about to pierce and lay its
eggs within ; 4, Eggs. (All but No.
4 much enlarged.)

This group includes a large number of small
brightly - coloured insects with metallic lustre ;
nearly three thousand European species being
known, while the tropics have not yet furnished
their contingent of species. The antennae are
always elbowed, and the wings broad with few nervures. Some of the larvae
live in galls, devouring the grub of the gall-wasp or those of the other inhabitants
of the galls. The members of the present order, scale-insects and plant-lice, are
alike subject to the attacks of the species of this family. One species {Leucopsis
gigas) found in Southern Europe lays its eggs in the larvae of a mason-bee, which
makes a cell of hard cement to protect its grub. Now the attacker has a boring
apparatus, and the problem is how to ascertain the whereabouts of a grub, bore
through the hard masonry, and lay eggs in the inmate. The cells are not distinct ;
but the whole number, which are made in a sort of colony, are covered with
cement, so that the task is doubly difficult. With the divining powers apparently
situate in the antennae, a suitable spot is chosen, and after, it may be, an hour or so
of continuous boring, the succulent morsel is reached and the egg laid. How the
wasp knows where the grub lies is not known. It seems to have the power — if not
of seeing — at any rate of feeling literally through a brick wall. One of the largest
members of the family is the gouty-legged wasp (Smicra clavipes), the egg
of which is laid in the larvae of certain water-insects. The wasp is glistening

HYMENOPTERA.

23

black, with reddish legs, the wings being better furnished with nervures than in other
members of the family. In the chrysalis-stinger (Pteromalus puparum) the egg
is laid in the chrysalis of several common butterflies during summer, while the
larvae remain in their host all through the winter, sometimes to the number of fifty.

1 3 2

I, gouty-legged wasp ; 2, chrysalis-stinger ; 3, Sketches of various Chalcididce (enlarged).

The Ichneumon-Wasps, — Family Ichneumonibje.

The species included in this vast family number upwards of six thousand, and
doubtless more remain to be discovered. The majority are parasitic on the larvae
of Lepidoptera, rendering good service to the agriculturist and gardener by holding
in check the enormous quantities of larvae hatched every year. Some, however,
attack other insects as well as spiders. The family is distinguished by the
variation of the wings, though these characters vary too slightly to be of much
value for generic or specific purposes. The antennae are of uniform thickness,
many-jointed, and, as a rule, filiform, though in some exceptional cases club-shaped.
The ichneumon-wasps do not hum, either when quiescent or on the wing, and are
thus enabled to approach the victim within whose body they wish to lay their
eggs with a greater chance of success. Having selected a suitable caterpillar,
the female deposits an egg with Jier ovipositor either on or beneath its skin. The
egg soon hatches, and the grubs feed upon the tissues of the larvae until full fed,
when they pupate in or around the now almost empty skin of the caterpillar. The
family has been divided into five groups, sufficiently distinguished from each other
in their typical forms, but merging into one another through transitional species.
Our first example is the ichneumon (Exenterus miarginatorius) figured in the
illustration on p. 24, which belongs to the subfamily Tryphonince, and is
found chiefly in pine-woods, where it is parasitic on Lophyrus pini, described on
p. 16. The female attaches an egg by means of a hooklet to the skin of the green
larvae, when nearly full grown. When the insect forms its barrel-shaped pupa, in
which to pass the winter, the parasite remains attached to the skin of the larva,
whose tissues it gradually absorbs. The perfect insect makes a small hole in the
pupa-case when it emerges, and does not, as does L. pini, bite off a little cap at
the top. Another type is Bassus albosignatus, which frequents the honey-dew
dropped by aphid colonies. It lays its eggs on various larvae which feed upon the

24

INSECTS.

aphides. In the allied genus Banchus, the species are parasitic on caterpillars,
especially those of the hawk-moths. The affected larvae do not even reach the
pupal state, but shrivel away, while the parasites form pupae within the empty
skin. The members of the typical genus and subfamily, such as Ichneumon
pisorius, are among the largest and most brightly coloured of the group ; their
colours, which are white, black, red, and yellow, occurring in great variety of
combination. The females are usually more brightly coloured than the males.
The former sex is easily distinguished by the filiform antennae, which are some-
times knotted, and may be observed to coil after the insect is dead. Many fine
species may be taken from moss in the spring, where they hibernate, though the
great majority appear in the summer and do not live through the winter. The
European species named is one of the largest, and may be regarded as typical of
the general appearance of members of the family. It is found from June onwards

1, Exenterus marginatorius, about to sting the larva of Lophyrus pini ; 2, Pupa-case of the latter with the
parasite emerged ; 3, With the proper saw-fly emerged ; 4, Bassus albosignatus, about to attack a Syrphus-
larva ; 6, Banchus falcator ; 7, Pupa of the ichneumon, (Nat. size.)

in pine-woods, where it attacks the larvae of the pine hawk-moth, depositing a
single egg in each victim. The caterpillar maintains its general health, and passes
into the chrysalis state as though nothing were amiss ; the only difference being that
a large ichneumon-fly emerges instead of the expected moth. An illustration of
the parasite is given in the illustration on p. 25, together with a pupa-case,
with the cap removed, whence the fly has escaped. Of the other forms here figured,
the male of Cryptus tarsoleucus gives a good idea of the general appearance of the
males of the ichneumons, with their narrow elongate abdomen. All the species of
Cryptus are parasitic on the larvae of the saw-flies, and the Bombycidce ; the female
laying several eggs in each larva. A fine handsome form is the one known as Mesos-
tenus gladiator, on account of its long needle-like ovipositor. It flies in June, and
may be found in the vicinity of old crumbling walls, where bees of various kinds make
their nest in the holes and crevices. In the same illustration is figured Ephialtes
inanifestator, representing the subfamily Pimplariinw. In some members of this
group the ovipositor issues from a ventral cleft in the abdomen, and in others from

HYMENOPTERA.

25

the tip itself ; the instrument being sometimes three times the length of the entire
body. All the species of the genus are much alike in general appearance, the
smaller kinds being parasitic on small larvae, and the larger on those of superior
They may be seen flying about in woods in summer, in search of the wood-

size.

1, Ichneumon pisorius, male, and empty pupa of pine hawk-moth, whence the parasite has emerged ; 2, Cryptus
tarsoleucus, male ; 3, Mesostenus gladiator, female ; 4, Ephialtes manifestator, male and female, the latter
laying her eggs. (Nat. size.)

boring larvae in whose bodies they lay their eggs. With intelligent agility the
female hurries over the trunk, but by what sense she ultimately detects the
presence of a larva within, and directs the ovipositor straight down to the spot, it
is impossible to say ; sight can be of
no assistance, nor, one would judge,
can touch. Can the antennae be used,
as the divining rod is supposed to be
used in the search for water, when
commonsense methods have failed ?
Possibly, however, the sense of smell
assists, and thus the seemingly
miraculous becomes once more a
common-place. The females appar-
ently follow the borings of the larvae,
for it would be next to impossible
for them to penetrate the hard fibres
of the timber in which their victims
burrow. One of the commonest
members of the family, and one of
the largest English forms, is Pimpla instigator, which preys upon many species of
larvae, especially those so destructive both in gardens and the forests. The perfect
insect may be seen on tree-trunks, in woods and hedgerows, searching for larvae,
with its wings raised, ready for instant action. The illustration represents this
species attacking the larvae of the satin moth.

Pimpla instigator, female to the left, stinging the larva of the
satin-moth. To the right is the moth, beneath it the
pupa, from which emerges the adult, while the male of
the parasite is seen below.

26

INSECTS.

Family BRACONID^:.

The members of this family are very similar in general appearance to those
of the last, though the differences in the number and form of the cells enclosed

by the wing-nervures forms an easy distinction. In
habits the Braconidce are similar to the Ichneumonidce,
attacking as a rule the larva3 of Lepidoptera, although
they are found as well in those of other insects. Up-
wards of a thousand parasitic grubs of the genus
Microgaster have been taken from a single caterpillar.
It must be remembered that the grubs are not in reality
gnawing at the vitals, but are nourished by the fluids
circulating through the system. As an example of the
family, we may take the genus Microgaster, which
comprises many of the commonest species. The females
of all, except two which are parasitic on Aphides and
the eggs of spiders, attack the larvae of Lepidoptera,
especially those clothed with hair. They are themselves
the victims of the attacks of a species of Pteromalus —
a genus of Hymenoptera briefly noted above.

Other Families.

In the family Evaniidce the abdomen is attached

above the middle of the metanotum, not to its lower

Microgaster nevwrum, female (en- margin. Among these is the javelin - wasp {Foenus

larged) ; its larva? are feeding jaculator), a species parasitical on Hymenoptera which

atthe nata LeT ^ ^ ^ breed m old walls. In the typical genus Evania the

species are believed to be parasitic on the cockroach,
depositing their eggs in the egg-capsules, and this habit will account for the presence
of a certain species on board ships, where cockroaches abound. The members of the
family Chrysididce are not easily mistaken for those of any other, being of moderate
size, and distinguished by the brilliancy of their colour, not only in the tropics but
even in temperate climates. The integuments are more or
less coarsely punctured, and the whole body glistens with
metallic lustre, golden-yellow, fiery-red, blue, and green, all
these being as a rule in combination. The perfect insects
are most numerous in the summer months, and may be
observed amongst flowers, on decaying timber, old walls,
and other suitable hunting-grounds. The females lay their

eggs in the nest of the various burrowing Hymenoptera. It is probable that the
grub devours the store of food garnered for its own progeny by the careful
mother. Possibly it makes little distinction between the food supply and the
tissues of the organism nourished by them. The common ruby-tailed wasps belong
to this family.

The golden burnished wasp (Stilbwm splendidum) is entirely steel-blue or

javelin-wasp, Foenus jacula-
tor (nat. size).

HYMENOPTERA.

27

golden-green. It occurs on the shores of the Mediterranean, and is also found
in Asia. It is one of the largest of the European forms. Among these, the
burnished blue wasp (Chrysis cyanea) is universally distributed throughout the
whole of Europe. The females lay their eggs in the larvae of those species of
Hymenoptera which make their nests in bramble-stems. The common golden
wasp (C. ignita) may be seen flying in search for the larvse of Hymenoptera,
whose burrows are made in old posts, walls, sand-pits, and other such places. Of
the royal gold- wasp (Hedychrum lucidulum), another of the commoner and more
beautiful species, a figure appears in the accompanying illustration. In the same

lilililllllW

mum

;:!lMHifc^v>sS&iS5

k-^^S.^.

i:#lliilf

4 3 2

BURNISHED AND GOLD WASPS.

1, Golden burnished wasp ; 2, Burnished blue wasp ; 3, Common gold wasp ; 4, Royal gold wasp, female ;

5, Brazen-tailed wasp.

illustration is also shown the brazen-tailed wasp {Elampus ceneus), of which the
female deposits her eggs in the grub of a small species of the Sphegidce.

The Ants, — Family Foemicid^e.

The ants bring us to the section Aculeata, the members of which differ from
the preceding section in that the females are furnished with a retractile sting in
place of an ovipositor. As a family, ants are characterised by having the first
segment of the abdomen and sometimes also the second reduced in size to form a
stalk for the rest of the abdomen. The workers, moreover, are without wings.
On account of their remarkable habits and intelligence, these insects demand a
fuller notice than is accorded to other groups. As regards their visual powers,
ants are very sensitive. While disliking any strong light suddenly thrown into
their nests, they prefer rays transmitted through a red medium, but object more
to those coming through green and yellow, while those through a violet medium
they abhor. Though sight is well developed, hearing seems much less so ; vibra-
tions of the air produced by tuning-forks, violin strings, or whistling, being little
heeded. Neither has any sound emitted by the ants themselves been detected,
3ven with the most sensitive instruments. The sense of smell is evidently keen,
for brushes dipped in scent arouse distinct curiosity. When the scent left in its
bract by an ant is obliterated, the ants next following are baffled, like hounds at
tault, until, after a little casting about, they pick it up on the other side. In
seeking for an object of whose existence and position they are aware, ants make

28 INSECTS

use of both sight and smell ; but it is in the latter that they place most confidence,
for if the object be removed only the space of an inch from its position, the ant in
search of it will make a number of cross journeys over the old resting-place before
it is successful. The scent, too, seems to be rather that left by former footsteps
than proceeding from the object itself. This sense of smell, and perhaps touch
combined, is obviously manifested in the caressing or recognition of friends with
the delicate antennae. The mysterious sense of direction is, after all, but sensitive-
ness to the direction in which the rays of light fall from a luminous object, and,
as such, is but a form of sight. This is proved as follows : — Ants made to cross
a wooden bridge would, in most cases, instantly turn round, if their heads were
turned in an opposite direction, by the bridge being made to rotate on a point.
And they would at once lose the sense of direction if light was shut out from the
artificial tract prepared for them, while if the candle were moved round in the
same direction as the bridge over which they travelled, though the direction be
changed, the ant does not become aware of it, because the rays of light fall from
the same point. Nevertheless, the sense of smell is evidently the stronger, for
ants carrying larvae from a cup to the nest still continue their course, although the
board on which they are travelling be turned right round. They follow the scent
of former tracks rather than take notice of the direction in which the light falls.

It is obvious that without some faculty representing, at anyrate, the rudi-
ments of memory, ants would not be able to recognise even the scent left by
comrades on the ground, nor would they persistently seek for an object which
had been removed. They exhibit, however, all the phenomena of true memory.
A fact, by repetition, becomes more firmly fixed as a sense-impression on their
brains. It fades away if not refreshed. Evidence in favour of a highty-developed
sense of memory is furnished by the fact that ants from a certain nest were in
the habit of journeying year by year, during the season of activity, to a chemist's
shop, six hundred yards distant, to a syrup-jar. It is scarcely likely that the jar
was found every year by fresh ants, so that memory alone will account for the
circumstance. It is perhaps in the recognition of friends, however, that ants
manifest the most extraordinary powers of memory. They invariably recognise a
friend, while a stranger is almost instantly slain. Ants held captive for months,
and returned to the nest, are recognised as lost friends, and caressed with the
antennas. This recognition might be merely a matter of the well-known odour of
a friend; but even then it must be a national smell, for it is scarcely possible
that each can recognise the personal scent of every individual. Not only do they
recognise the perfect ants, but even the offspring, or eggs, removed and hatched in
other nests, and returned home full grown, are recognised as kith and kin, while
their foster-mothers are slain. One can hardly suppose that the scent, unless
such be inherited, would account for such recognition.

Whereas ants show evidence of such feelings as rage and combativeness, the
emotion of sympathy is by no means as constant or intense as might be supposed
from their general intelligence and power of recognising friends. Mutilated ants,
and those in difficulties, are passed by on the other side ; but an intoxicated ant
staggering in its tracks does not fail to excite astonishment, and is carried off as
a sort of curiosity to the nest. Chloroformed ants, however, are dropped into the

HYMENOPTERA. 29

water, where they were, of course, motionless. That ants have the power of com-
municating- intelligence admits of no doubt. Two ants were introduced, the one
to three hundred or six hundred larvae in one glass, the other to two or three in
another glass, each took a larva and returned to the nest. A larva was added to
the second glass every time one was taken. In forty- seven and a half hours the
ant which was introduced to the six hundred larvae had brought two hundred and
fifty-seven friends to help, while the other in fifty-three hours had brought but
eighty-two.

The swarms of ants which in spring rise in clouds are males and females.
This is their nuptial dance, and for hours they circle and sport in the sunshine.
The males fall and die, or are destroyed by numerous foes. Nor is any assistance
offered them by the workers, who well know that their vocation in life has been
fulfilled, and they themselves are no longer of any use. The females having
divested themselves of their wings, with claws and legs, set about founding new
colonies. The eggs, however, must be nursed if they are to hatch, and are
subjected to much licking by the nurses. Then the larvae must be fed ; next, they
are carefully cleansed and carried for their daily walk through the lanes of the
nest. Not even after the grub has become a pupa is the ant allowed to emerge
without assistance. Biichner writes that "the little creature when freed from
its chrysalis is still covered with a thin skin, like a little shirt, which has to be
pulled off. When we see how neatly and gently this is done, and how the tiny
creature is then washed, brushed, and fed, we are involuntarily reminded of the
nursing of human babies." Next, they are taught their domestic duties, and to
distinguish between friend and foe. If the nest is attacked, the older and more
experienced fight, while the younger members remove the pupae to a place of safety.

Ants not only feed upon the honey-dew dropped by plant-lice upon leaves,
but also rear aphide eggs, and feed the insects for the sake of their secretion.
Tunnels, or covered ways, are made by some ants up the branches of the trees
where the aphides live, so that the insects are enclosed and kept prisoners.
Certain portions of the tunnels are enlarged to form stables, where the aphides are
penned, the doors being large enough for the narrow ants to enter and leave, but
not for the rotund plant-lice to escape. The ' cows ' are induced to part with a
drop of honey-dew by a gentle stroking with the antennae, and general encourage-
ment of other kinds. Ants are far in advance of human dairymaids in the matter
of tact in dealing with their cows. Colonies of aphides have been carried by ants
to fresh pastures.

It is no long step from cow-keeping to slave-making. At least three species
of ants indulge in this reprehensible practice. A raid is organised against a
neighbouring nest — warriors and workers are slain, and the pupae carried off,
hatched, and reared, soon to work and fight for their masters in the land of their
captivity. In some cases the slaves are kept for indoor occupation, and are carried
off, as part of their goods and chattels, by their masters, when they migrate into
new quarters. Another species does not work at all, neither males nor females ;
the workers — sterile females — capture slaves, but do no more. They neither feed
their young, nor make their nests, — a city-state entirely dependent on slave-
labour. Not only, however, do slave-making ants engage in expeditions against

30 INSECTS.

other communities for the purpose of securing servants; but even many ants,
whose energies are confined to agriculture, not infrequently wage war for the sake
of plunder on others whose habits of life are similar. An expedition of the former
tribes usually consists of a general attack upon the nest of a species which they
are in the habit of enslaving. Single scouts are sent out to reconnoitre, whose
business it is to investigate the position of the nest and the whereabouts of the
entrances. Having satisfied themselves of the feasibility of an attack, they return
to their own nest, and summon forth the hosts of ferocious warriors. These
encouraging one another with taps of the antennae, march on the unhappy colony,
whose baby inhabitants they propose to enslave. Of all the warriors the most
warlike are the amazons (Formica rufescens), robber-ants of great size, strength,
and courage. A column is formed, and, guided by the scent of their prey, as they
come within the radius of their victims' pathways to and from their city, in
hundreds they rush onwards. An hour, it may be, after the start, the nest is
reached and entered, and soon the struggle becomes a furious battle, on the one
hand to save, on the other to carry off the larvae. Up the neighbouring trees the
owners fly with their precious burdens, a harbour of refuge, secure from danger,
for here the Amazons cannot follow — specialised to kill but not to climb. Others
hang on the flanks of the retreating columns and harass the thieves bearing off
the tender pupae. A nurse seizes one end of her nursling, the Amazon has the
other, imperceptibly the jaws of the latter steal up, still holding on, towards the
far end, till the nurse's head is pierced. Sometimes the Amazon lets go, and the
nurse is gone in a trice, and the pupa with her, while the warrior contents itself
with a vicious grin as the embryo slave vanishes into the tree-tops. The slaves
left behind in the city are ready to receive the plunder ; and soon more slaves are
hatched, whose prison is now their home, for they have never been conscious of
another. But success does not always smile upon their expeditions ; an entire army
may lose the way, courage may fail the leaders, disputes may arise, and general
unaccountable want of esprit de corps, breaks their resolution, and the attack is
abandoned. Many a warrior loses its way emerging from the ravaged nest by
passages which open to the thicket far from those they entered by. The sense of
smell is of no avail, that of direction does not rise to the occasion.

Another robber-ant (Formica sanguinea), not so well furnished with offensive
weapons, but larger and more intelligent than the former, also sallies forth in
search of slaves. Both may meet in combat on the march, and the dead and
dying mangled remains, and heads and legs nipped off", bear witness to the
consequences. These robber-ants do not attack a nest with a rush, as do the
Amazons. They lay deliberate siege to it, surround it, securing the entrances and
exits. None of the inhabitants are allowed to pass if they carry pupae.

Of the other inmates of ants' nests such as beetles, crickets, spiders, wood-lice,
and the like, want of space forbids mention, ancL indeed, the reason of their
presence is not obvious. The supposition that they are kept as pets possibly
derives support merely from the analogy drawn from similar whims amongst
human beings. That ants sleep is an undoubted fact, and so too that they bestow
much care upon their toilet, assisting each other in this respect. Bates writes
that "here and there an ant was seen stretching forth first one leg and then

HYMENOPTERA.

3i

another, to be brushed and washed by one or more of its comrades, who performed
the task by passing the limb between the jaws and tongue, finishing oft' by giving
the antennae a friendly wipe." Recreations, too, are not unknown to them ;
running after each other in hide-and-seek, followed often by a rough-and-tumble
game. Stranger still, they hide away the dead bodies of their friends in chinks
and crevices far from the nest, and thus perform a sort of burial. That the
habit is more than the desire to be rid of what is useless, or may be injurious,
seems doubtful ; unless, indeed, such device lies at the root of all funeral customs,
as is not improbable.

Of the British species, the largest is the red wood-ant (F. rufa). It
abounds in fir-plantations in the southern counties of England, and the huge
heaps of pine-needles it gathers over its nest are familiar objects to frequenters

1, honey-pot ant ; 2, parasol-ants on the march ; 3, Dwellings of husbandmen ants. (Nat. size.)

of the forests; while the size, ferocity, and numbers of the ants themselves

become a nuisance even before their ways have ceased to be amusing. If the

nest be disturbed, the fumes of formic acid burst out full in the face of the

intruder, while the jaws of the enraged inhabitants render further operations

impossible. Numbers of nests, however, are annually ransacked of their pupae

for young pheasants, which often seem surprised by the flavour of the ants, which

they pick up with the pupae. Highways cross the paths in every direction

iround the nest, and the ants may be seen coming and going continuously

jhroughout the day, bringing in twigs, caterpillars, and fragments of all kinds of

nsects, to be safely stored away in the nest. Still larger is the Hercules ant

Camponotus herculeanus), which inhabits wooded highlands in continental Europe,

md constructs its nest in decayed tree-trunks. The female measures more than

lalf an inch in length ; and the insects, when swarming, gather in a cloud around

he base of some tree. In colour the body is glistening grey, while the tips of the

vings are yellow. The honey-pot ant (Myrmecocystus mexicanus), of which the

32 INSECTS.

habits are alluded to above, inhabits the highlands of Mexico and South Colorado.
The nest is constructed in the ground, usually beneath hillocks, in a gravelly soil,
and contains passages and chambers arranged in different storeys, some for food,
others for the larva?, and the third for the honey-pots. The inhabitants condemned
to servitude in the honey-secreting department of this community are never
allowed out. An allied species is found in Australia. Still more curious is the
South American satiba, or parasol-ant (CEcodoma cephalotes), dreaded on account
of the havoc it works amongst the foliage of plantations. Agriculture, too, becomes
next to impossible where these destructive insects abound. They are not without
their uses, however, for the Indians regard the females when full of eggs as a
delicacy. Seizing the insects by the thorax, they nip off the luscious morsel with
their teeth, much as we may see monkeys behave towards a fly. The nests of this
species are prodigious. Bates speaks of hills forty yards in circumference, or about
twelve yards across, while others are of even larger size. This hill, huge as it is,
is merely the outer covering of a network of galleries extending deep and far into
the ground, with many outlets into the surrounding country, usually carefully
secured. The workers, of which there are two forms, look after the progeny and
gather food ; while the soldiers, with broad heads and terrible jaws, sally forth if
danger threatens their citadel. The stronger workers march in daily procession
to the plantations in search of leaves, and return, each with a piece securely held
in its jaws. The more slightly built remain at home, engaged in the less arduous
operations of domestic economy, and rarely venture far from their nest. These
leaf-cutting expeditions are directed chiefly against coffee- and orange-plantations,
and the ants, accompanied by a detachment of soldiers, partly no doubt to keep
order, and more especially to guard the caravan against freebooters, march in
large columns to the groves, climb the trees, and begin to reap their daily harvest.
Each ant having cut with its toothed mandibles a piece of leaf half an inch in
diameter, descends the tree, holds its booty high in the air, edge upwards, and so
homewards. The leaf-discs thus held above their heads have earned for these
insects the name of " parasol-ants." The path they travel on is soon beaten down
with footsteps, and worn till it becomes a deep groove; but even height does
not end their activity and mischief, for they make raids on the houses of the
planters in search of groceries and sweetstuffs, appearing often in swarms. There
are several species of this genus with similar habits, and all are known by the
natives of Brazil under the single name saiiba. An illustration of one of the leaf-
cutting expeditions returning homewards is given in the illustration on p. 31.

Family MUTILLID^E, etc.

The species included in the families Mutillidce, Thynnidce, and Scoliidcv,
number from twelve hundred to fifteen hundred. The females of members of the
first two are wingless, while those of all three families possess a formidable poison-
sting. Of the European Mutilla europcea, the males may be seen, though not
commonly, amongst flowers, and frequenting foliage infested with aphides. The
wingless female may, however, often be met with on sandy commons in summer.
The larvae are found in the nests of humble-bees, where they feed upon the grubs.

HYMENOPTERA. 33

All species of the family, however, are not parasitic on humble-bees, for in South
America, where the tribes of the former are scantily represented, those of the latter
are numerous. Of the third family, we take as example the formidable Scolia
nemowhoidalis, which is found in Turkey, Hungary, Greece, and Southern
Russia. Not very much is known of its habits and life-history, but such as is
points to a larval life parasitic on various beetles ; while other members of the

Mutilla europcea—1, Female ; 2, Male ; and Scolia nemorrhoidalis — 3, Male ; 4, Female.

family have been taken from nests of the parasol-ant. In the Scolidce the wings
are present in both sexes. Figures of the male and female are given in the
illustration above.

Family BEMBICID^E.

The members of this family are distinguished from the under-mentioned
Sphegidai by the formation of the labrum, which is much produced. In general
appearance they resemble the hornets and larger wasps. Bembex rostrata, figured
on p. 35, is found not uncommonly throughout Europe, but becomes more local in
the northern countries. The insects fly in circles, with a loud hum of their power-
ful wings round and round the burrows which the female makes in the loose sand
or earth. Here are stowed away the bodies of large flies, reduced by an application
of the sting to a state of unconsciousness ; and in each nest a single egg is laid, the
grub when hatched feeding upon the food which it finds placed within its reach.

Family POMPILTD^J.

In this group the males are characterised by their slender form and small
size ; and both sexes may be recognised by their energetic hurrying to and fro
with quivering wings and antennae, moving rapidly on all sides, as they search
sandy commons for a suitable spot to burrow in, as well as for the spiders which
they numb with a sting and store up for the larvae. The members of the family
are universally distributed, being larger and more brilliant in tropical countries.

VOL. vi.— 3

34

INSECTS.

Some make their nests in the beetle-borings of old trees and posts, and prey upon
all kinds of insects and their larvae ; others prey exclusively on spiders, and confine
their burrowing operations to sandy soils. Not only do spiders of the family
Lycosidce, which run freely on the surface of the ground but make no nest, fall
victims to the Pompilus, but the Epeiridce are snatched from the very centre of
their maze and carried off, their powers of resistance rendered futile by one
paralysing stroke of the poisonous sting. Well are these spiders aware of the
danger, for they drop instantly from their webs into the herbage when the hum of
wings warns them of the near presence of a wasp. Others, however, whose staple
food consists of bees and wasps, are not so easily alarmed, and learn to distinguish
between friends and foes. The figured Pompilus natalensis is of considerable
service in Natal, since its habit is to search every nook and cranny for house-
frequenting spiders. Up and down the windows, in and out amongst the rafters,

1, Pompilus natalensis ; 2, Pompilus trivialis ; 3, Larva of latter on garden spider ; 4, Priocnemis variegatus ;

5, Agenia punctum, with its two cells.

the female passes to and fro in search of the large spiders which lodge in their
webs hung up amongst the woodwork. The victims when captured are buried
with the egg in a hole in some suitable corner within or without the house. A
large species of this genus attacks spiders of the genus Lycosa on English commons,
and buries them in a somewhat similar fashion. The second species figured in the
illustration (P. trivialis) also attacks spiders, especially Lycosa inquilina.

Family SPHUGID^J.

Many of the handsome insects belonging to this family are uniformly black,
black and red, or yellow and black. The majority, however, are black with brilliant
yellow or white markings, and shine with the lustre of burnished metal. These
markings are very variable even in the same species, rendering their identification
difficult for the student, though on account of that contrast of colour, and the

HYMENOPTERA. 35

activity of their movements, the members of this family are amongst the most
attractive of all hymenopterous insects. Some species prey upon lepidopterous
larvae, others on grasshoppers, while another provisions its nest with three or four
crickets. These latter, however, are not captured without a severe tussle. The
Sphex leaps upon the cricket's back, delivers a couple of stings, and all is over.

Family CrabeoniDjE.

The numerous members of this family are usually black with yellow markings.
Their nests are formed either in the ground or in decaying timber ; the tunnels of
wood-boring beetles being utilised in the latter case. While the smaller species
feed chiefly on aphides, the larger kinds are more partial to flies. Figures of three
species, viz., Crossocerus scutatus, C. elongatulus, and Crabro patellatus, are given

Mellinus arvensis — 1, Male ; 2, Female ; 3, M. sabulosus ; 4, Bembex rostrata ; 5, Philanthus triangulum, Cerceris
arcuaria ; 6, Male ; 7, Female ; 8, Trypoxylonfigulus ; 9, Crabro patellatus— Female ; 10, Male ; 11, Crossocerus
scutatus— Male ; 12, G. elongatulus ; 13, Oxybelus uniglumis. (1, 10-13 enlarged, the rest nat. size. )

in the annexed illustration. Another form is Mellinus arvensis, usually met with in
pine-woods, where it may be seen searching about on the sandy soil, and is particu-
larly fond of the honey-dew deposited by aphides. A smaller form (M. sabulosus)
is likewise shown in the illustration. The same illustration also shows Trypoxylon
figulus, a black insect, which may be observed throughout the summer flying
busily to and fro among posts and decaying trees. A variation in the mode of
making its cell will be noticeable. Selecting a long tunnel, the female brings in
aphides or small spiders, lays an egg, deposits a suitable supply of food, and fits on
the top a wad of mud, above this again another cell is constructed, similarly
capped with mud, and so on till the tunnel is full.

36

INSECTS.

Family PmLANTHlDJZ.

As an example of this family may be taken Philanthus triangulum, the larva
of which feeds upon the honey-bee, and other members of the same group. In
the illustration on p. 35 a figure of this species is given. Since, at least, five
bees are provided for each larva, the havoc caused in hives where these insects
abound must be considerable. A separated nest, in some warm sunny slope, is
made for each egg. Another form is Oxybelus uniglumis, figured in the illustra-
tion on p. 35. In this species the female excavates tunnels in sandy ground,
to which the sunshine has free access, and flies are mainly used to provision the
nest, as a rule one only to each cell. The fly is attacked from above, knocked
down, stung in the neck, and carried off to the nest. A third form (Cerceris

common leaf-cutter bee. a, b, Female arid male (enlarged) ; c, Rose-leaves with several pieces clipped out and a bee
at work ; d, Nest in a willow stem ; e, A single cell ; /, The lid of same ; g-h, Pieces of leaf ; i-k, Side pieces.

arcuaria), shown in the same illustration, is a black insect with yellow bands
on the abdomen, as are most of its kindred.

Wasps and Bees.

Before taking into consideration the families into which these groups are
divided, it is advisable to give an account of some points connected with their
habits, as well as a notice of their special senses. As regards sight, the large size
of their compound eyes, in addition to the presence of ocelli, indicates their high
degree of visual power. In respect of perception of colour, experiments have
shown that if honey be placed on cards of different colour, bees show a decided
preference for special tints; orange and yellow being the prime favourites.

HYMENOPTERA. 37

Similarly, no doubt, the colours of flowers have a greater or smaller degree of
attraction for these insects. Indeed, it is beyond question that the fertilisation of
flowers by the visitation of bees has tended to the development of the special
colours patronised by the insects, while blossoms which were of less favourite hues
have gradually disappeared. Black, white, and green flowers are not so common as
yellow, orange, blue, or red ; and black is less prevalent than either of the others.
Although experiments to prove or disprove the sensibility of bees to sound have so
far been negative, yet from the fact that they are exceedingly sensitive to a certain
peculiar cry occasionally emitted by the queen, which acts like an electric shock, it
would appear that hearing is likewise well developed. That bees and wasps are
able to find their way, and to fly off apparently without hesitation straight for
home, needs no proof. But this power does not necessarily indicate some mysterious
sense of direction, enabling them to perceive their bearings by occult means.
Rather may it be looked upon as due to the ordinary observance of conspicuous
landmarks, such as are utilised for guidance even by man himself. Bees, for
instance, have been taught the way to a store of honey by the repetition of single
experiences, proving that they pass from the unaccustomed to the well-known,
little by little. Naturally, the direction of a point to which whithersoever they
may wander out, they must invariably return many times a day, soon passes from
the sphere of calculation and enters the region of simple intuition ; so rapid and
unconscious are the various acts of perception involved. That these insects do
thus take note of landmarks has been shown by Bates, who describes how a sand-
wasp carefully marked the spot where half of a larva had been left by circling
round and alighting in the vicinity. And even then, when it returned, though it
flew many times straight to a certain conspicuous leaf close above the booty,
doubtless a landmark yet it could not for a long while — and after repeated pounces
in the wrong direction, and more it seemed by good luck at last — succeed in finding
it. No one who has heard the cry of an angry wasp, and experienced the pain
which has followed, will doubt that anger and malice have their places in the
wasp's nature. Often do these insects seem to make straight for an innocent
bystander, and sting from pure spitefulness. Sympathy for the ailing and
wounded, as amongst the ants, so amongst the bees, seems to be more noticeable
than it is towards those actually in distress, — though uninjured. It has been
doubted, indeed, whether bees show any affection for one another ; the caressing
antennae, as well as the personal attentions to each other so noticeable in the case of
ants, are certainly lacking. As in ants, however, the antennae seem to be the chief
organs of communication.

As regards habits, there are two chief operations in which bees and wasps
engage, namely, the procuring of food and the rearing of a progeny. This food is
of two kinds, — honey gathered from the nectaries of flowers, and bee-bread, or
flower-pollen moistened with honey, kneaded by the workers, and stored away, for
feeding the larvae. The workers, or honey-gatherers, do not bring in more than
one sort of pollen at the same time ; and when the nurses, or domestic bees, receive
the pollen from the honey-gatherers they keep it carefully separate. The sort of
pollen is more nutritious than another, and a female larva fed on the more nutri-
tious bee-bread will become a queen or fertile female, and one hive cannot afford

38

INSECTS.

more than a few of such luxuries. Those fed on the less nutritious bread turn out
workers, or non-fertile females. For the males special conditions are arranged by
the queen when laying the eggs. Royal cells, framed for the feeding of queens,
are much larger than those for workers. In secreting wax for the cells, bees
having eaten as much honey as they can conveniently carry, hang in a cluster from
the top of the hive. Soon the wax begins to burst from glands beneath the edges
of the segments of the body, and is rubbed off with the legs. Cell-construction
now begins, and in addition to the wax, a sort of resinous cement, drawn from the
sap of conifers, is used to strengthen the walls at their angles, and also to cover the
inside of the hive. The six-sided form of the cells of the honey-bee
appears to have been evolved after ages of gradual modification from
the simple cylinder which would be formed by a cylindrical body — as that of a
bee — moulding wax around itself ; this form alone admitting of the greatest
number of cells being placed side by side, and tier by tier, without leaving waste

Honey-Bee.

INMATES OF A HIVE.

A — 1, Queen ; 2, Worker (non-fertile female) ; 3, Drone or male ; 4, Mandible from outside. (All slightly enlarged.)
B, Hind-leg of worker ; c, Thigh (femur); b, Shank (tibia) ; a, First tarsal joint. C, Egg (much enlarged). D,
Larva and pupa (nat. size). E, Longitudinal section of the abdomen of a worker ; 1, Honey-crop ; 2, Egg-sac ;
3, Poison-sac ; 4, Oil-gland ; 5, Semen-sac or spermatheca ; 6, Sting ; c, Segmental interstices, whence the wax
issues. F, Mouth-parts ; a, Maxillae ; d, Basal joint of same ; b, Labial palpi ; c, Tongue. G, Bee-louse and
its pupa (much enlarged). H, Brush (much enlarged). J, Poison-apparatus ; a, Poison-gland ; b, Poison-
vesicle ; c, Sting-groove ; a, Sting ; e, Sting-sheath. (All much enlarged.)

vacant spaces between. The greater the number of the cells the stronger the
colour, the stronger the colour the more numerous the swarms and the greater the
chance of the perpetuation of the race. The intermediate form between the cylinder
and the regular hexagon is found in the comb of the Melipona bee, which forms
cylindrical cells, but so close together that the partition-wall becomes a flat-plate,
since it is impossible for a thin sheet to be concave on both sides at once ; modifi-
cations from this form combined with modified instincts would eventually produce
a regular hexagon. It is to be borne in mind, however, that this form arises not
because the bees are aware that a regular hexagon is the most economic form of
cell they can adopt, but simply because, when a group of bees stand close to each
other, and form cells of pliant wax, — whose walls break through at all points on
account of their proximity, rendering it necessary to build up a flat wall between, —
they cannot fashion it in any other way. For at all points of a single cell, six bees

HYMENOPTERA. 39

at the sides, and six bees below are constantly encroaching and fitting in the sides
and corners of their own cells, around that of each single bee. Bees have proved
in practice what to the mathematicians is inevitable in theory. Nevertheless, bees
are not compelled to form their combs in this or that way without any power of
adaptation to special circumstances. They construct their comb and hang their
connections wherever the holding seems likely to be most secure, and thus, on a less
complicated plane of intelligence, carry out precisely what human beings accom-
plish under more complex conditions, namely, they adapt means to ends. The
difference is one of degree, not of kind.

The fact that eggs are laid by a single female of unusual size is note-
worthy. Bee-colonies, however, unlike those of the social wasps, are permanent,
hibernating during the winter. Each wasp-colony or nest originates from a single
female, which survives through the winter and by herself lays the foundation of
a new colony. Among bees a certain number of workers, or non-fertile females,
are set apart as maids-in-waiting, who attend to the queen's wants in the matter of
food, which are considerable during the period of laying. A single egg is laid in
each cell, and, as mentioned above, larger cells are set apart for the queens ; the
difference between these and the non-fertile females being entirely brought about
by the difference in food. This, however, is not the case with the males, and it is a
disputed point whether the queen can control the sex of any particular egg, or
whether she can select a male egg as she proceeds with the laying. Certain it is,
at any rate, that when she reaches a drone or male-cell, which is larger, she
deposits an egg which will become a male. It has usually been asserted that
unfertilised eggs become males, while those which are fertilised turn out females.
This may be the case, and certainly would tend to bear out the general truth that
absence of nutrition tends to give the male element greater preponderance in the
progeny, though the immediate physical conditions on which the sex of the offspring
depends are imperfectly known. A superabundance of males is, as a rule,
associated with failing provisions and loss of bodily energy, and this is borne out
by the fact that when the queen is old she is apt to lay too many drone-eggs.
This, however, is a failing which the community cannot put up with, and if the
queen be unable to produce profitable offspring she is put to death. Still both
bees and queens well know that the one supreme calamity which can befall the
bee-community is to be left without a queen, not because they need her rule,
but because on her alone rests the future of the colony. And it has been
asserted that if two queens only remain, and are contesting for the mastery,
and each should simultaneously have the chance to deliver a sting which might
prove fatal to both, each releases the other, dreading to leave the hive queenless.

Inseparable from these phenomena is that of swarming; or the
Swarming. m » • • •

budding off of new colonies from the mother-hive. Owing to the

instinct of the workers, who can arrest or accelerate development ■ by regulating

the food-supply, a new queen is always ready when a swarm of bees is prepared

to leave the overcrowded hive. This queen is, however, not permitted to leave

her cell till the actual moment of flight ; and all along has to be protected from

the reigning queen, by whom, if opportunity were afforded she would be killed.

Indeed, when the swarming season is over, the actual sovereign is permitted to

4°

INSECTS.

make short work of all her rivals. The function of the nurses, as their name
implies, is to rear the young, and, if necessary, preserve the queens. After the
males, or drones, have fulfilled their duties, they are massacred in thousands by
the workers ; even the young grubs and pups3 being dragged from their cells and
killed. In many wasp - societies, these matters are, however, more leniently
arranged, since the males usually assist in the general duties of the colony. Still
even these exhibit an unaccountable habit, all the grubs and pupee being dragged
out and slain as winter approaches. Whether the wasps themselves begin to experi-
ence the pinch of hunger, and wish to close mouths which must otherwise starve,
or what may be the motive for such action, is beyond our ability to guess. Since
every wasp, save here and there a large female, or queen, perishes at the approach
of winter, the massacre cannot be justified on the score of prudential social policy.

Solitary Wasps and Mud- Wasps, — Families Masarid^e and EUMENIDJS.

The true wasps may be conveniently divided into solitary and social wasps,
although there is a more or less complete transition between the two. Of the typical

MUD-WASPS.

1, Odynerus parietum, female, with nest ; 2, Chrysis ignita ; 3, Polistes, gallica, female and nest.

solitary wasps (Masaridce), which are mostly tropical forms, and constitute a link
between the parasitic wasps described above and the Vespidce, but little is known.
Some kinds are, however, parasitic, and possibly many may be so. On the other
hand, the Eumenidce are solitary wasps, which make their nests chiefly in mud-
walls or sandstone cliffs ; some constructing a series of mud-cells in the hollow
stems of plants, and supplying their grubs with caterpillars for food. A well-
known European example is the figured Odynerus parietum, a variable insect,
making its appearance in May and June. The nests are made in holes of old
mud-walls, or the banks of clay-pits, and are filled with grubs of beetles belonging
to the family Chrysomelidce, or with the' caterpillars of small moths.

Social Wtasps, — Family Vespid^j.

The members of this group form a link between the foregoing and the true
bees, since each species includes a fertile female or queen, unfertile females or

HYMENOPTERA.

4i

workers, and males or drones. The nests are formed of a kind of paper manu-
factured from the dry parings of old posts and trees. Since we have already dealt
briefly with the general habits of the Vespidce, further reference to them, save as
occasion for their mention arises in the course of subsequent description of species,
will be unnecessary. The members of the family may themselves be distinguished
at once from all other Hymenoptera by the peculiar arrangement of the wings
when folded at rest. The fore -wings partly enclose the hind- wings, both pairs
lying along the sides of the abdomen, not concealing it from above. The food of
wasps consists of the saccharine matter derived from various vegetable products
and also from animal matter. As regards the distribution of species — apart from
the usual increase in size and beauty of colouring — it may be remarked that the
closer the equatorial regions are approached, the more numerous do members of

LIFE-HISTORY OP THE HORNET.

a, b, Adult; c, Portion of brood-cells ; d, Larva; e, Pupa, (d and e somewhat enlarged.)

this group become. Of the better-known forms the common hornet ( Vespa crabro)
is readily distinguished from other species of wasps by its large size and the
prevailing red tint on the anterior portions of the body. It is universally dis-
tributed throughout Europe, and occurs as far north as Lapland. The solitary
female, after her hibernation, commences to build the first foundation of her nest
in May on some convenient beam in a loft or outhouse, or frequently in the
holes made in the eaves of thatched cottages by sparrows. The food of the grubs
consists of the bodies of insects, bees, etc., which the workers chew up for their
benefit. On the approach of autumn the remaining larvae, which have not yet
been hatched out, are torn from their cells and left to perish. Under the title of
common wasps no less than five species may be included, although V. vulgaris is
the common wasp par excellence. V. germanica may be recognised by the three

42

INSECTS.

SOUTH AFRICAN WASP AND ITS NEST (nat. size

black spots on a yellow clypeus. V. vulgaris presents a longitudinal black line
dilated at the extremity. V. rufa is rare in Northern Europe. V. media has the
yellow markings of the abdomen darker than in the other species. The wood-
wasp, V. silvestris, hangs its nest on the bough of a tree or shrub. Such brief

notices are, of course, wholly inadequate
for a student of the group ; and reference
must be made to writings devoted to the
special points of difference between these
closely allied species. Among other forms
space only admits mention of the South
African wasp {Belonogaster), of which
the comb is shown in the annexed figure.
Common in houses at the Cape, this
insect is much dreaded on account of the
severity of its sting.

Solitary Bees, — Family AnbreniBuE.

These insects may be recognised by
the fact that the pollen-collecting organs
are situated on the femora and coxse of
the hind-legs, and the neighbouring sides
of the thorax. The genera Andrena and Hylceus comprise the greater part of all
the wild bees of Central and Northern Europe. The perfect insects appear in
the early spring, making their nests in sandy soil. In the first genus figures of
three species (A. schencki, A. cineraria and A. fulvicrus) are given in the accom-
panying illustration. H. grandis, figured on the same illustration, flies in July
and August, and forms a large number of holes — a kind of colony — in some sunny
slope. The species of both Andrena and the allied Halictas are parasitic, and
display a very curious habit. When retiring to rest they fasten upon a twig or
the edge of a leaf with their mandibles, fold their wings, draw up their legs, lay
the antennas neatly along their backs, and, having induced a temporary lock-jaw,
hang securely until the morning, when they loose their hold and hurry off once
again to play the parasite on their relatives. Another species figured in the same
illustration is the hairy -legged bee (Dasypoda hirtipes), which appears on the wing
in July, and constructs a nest of about six cells in sandy ground. The burrow
runs obliquely at first, afterwards descending perpendicularly. Another well-
known type of the family is exemplified by the mason-bees, of which one
species (Chalicodoma muraria) is represented in the annexed illustration. These
insects make their appearance in Europe during May, when the female forthwith
sets about constructing her nest. This includes not more than ten simple cells,
and is attached to old walls or houses ; the cells being formed of grains of sand
glued together with the saliva of the builder. In 1886 some bees of an allied
genus (Osmia) constructed their nests in the locks of a door at Deptford. The
cells had completely choked the works of the locks, and in one case a portion of
the nest was forced out by the insertion of the key without driving away the bees.

HYMENOPTERA.

43

As the locks were in pretty constant use, it would appear that all the nests must
have been built within a few days.

The leaf-cutter bees, of which an example {Megachile centuncularis) is figured
on the illustration on p. 36, take their name from lining their nests with cells

GROUP OF SOLITARY BEES.

1, 2, Hairy-legged bee {Dasypoda hirtipes) ; 3, 4, Shenek's earth-bee (Andrena schencki) ; 5, 6, Grey -haired
e irth-bee (Andrena cineraria); 7, 8, Brown earth-bee (.4. fulvicrus); 9, 10, Large burrowing bee (Hylasus
(/ -andis). A male and female of each is figured. (All of nat. size.)

i lade from fragments of leaves nipped out by the strong jaws of the

These cells may be placed either in the holes of trees, in clefts and crannies

\ 'alls, or in specially con-

s;ructed burrows in the

ground. Among the leaves

most generally employed

a -e those of the poplar,

h Drnbeam, privet, poppy,

a id rose. The mode in

v hich these insects work,

a id the structure of their

c< lis and burrows are

e ihibited in the illustra-

ti m. Yet another type

o building is exemplified

b - the carpenter - bees

(„ 'ylocopa), which are

k longst the finest mem-

b rs of the entire family.

insects,
of old

MASON-BEE.

1, Nest with bee emerging and larva in an open cell ; 2, Male ; 3, Females
fighting. (Nat. size.)

44

INSECTS.

Their cells are built in rows in the solid wood of trees, and the method of procedure
will be observed in the illustration exhibiting the violet carpenter-bee (X. violacea).
This species, which is rare in Northern Europe, forms a series of cells in each of

which lies a larva, and since the lower
ones are obviously the oldest, it is some-
what difficult to understand how the newly-
-emerged perfect bee escapes into the upper
air from the lower cell. At present it is
not altogether clear what course it takes ;
whether it gnaws its way through the
chambers where brothers and sisters are
peacefully awaiting future developments —
at the imminent risk of arresting all
chances of such by thus breaking into their
bedrooms, to the detriment of nervous
systems not yet hardened to bear the strain
— or whether it gnaws its way straight
out at the side, seems a matter of doubt.
Some authorities state that the female has
already foreseen and guarded against such

VIOLET-WINGED CARPENTER-BEE, WITH CELLS CUT OUT -i • i i •• • i

in a tree-stem undesirable contingencies, by preparing a

door of escape at the bottom of the lower
cell. And they record as a remarkable fact that the bees, each in turn, gnaw
through the floor of its cell, and of course find their elder brother or sister already
flown from the cell next below. They never go in the opposite direction through

1, 2, hairy-legged flower-bee (Anthophora kirsuta), female and male , 3, 4, tufted flower-bee [A,
retusa), female and male ; 5, wall-nesting flower-bee (A. parietina), female ; 6, 7, long-horned bee (Eucera
longicornis), female and male. (All of nat. size.)

the roof. Our next examples of this family are the flower-bees {Anthophora), of
which three species are shown in the annexed illustration. In general appearance
these insects closely approximate to humble - bees. They build their nests in

HYMENOPTERA.

45

burrows in the ground, in holes of trees, or clefts and cracks in walls ; the cells
being separated by partitions, and made of the ruins of the burrow or cleft.
Generally the whole nest has the form of a twisted tube. Like their allies, these
bees are solitary, and, like humble-bees, are much infested by parasites. Finally,
we have the long-horned bees, of which one species (Eucera longicomis) is shown
in the same illustration. These bees construct smooth tunnels in the earth, divided
as usual into sections, each of which contains one egg, together with a supply of
pollen and honey for the future larva.

True Bees, — Family Apidje.

In this group are included not only the various kinds of honey-bees, but
likewise their more clumsy cousins the humble-bees. Such a well-known insect
as the common honey-bee ( Apis meliftca), of which the habits have been already
referred to, requires no special notice; but it is important to observe that the

1, COMMON HUMBLE-BEE WITH NEST; 2, STONE HUMBLE-BEE. (Nat. size.)

honey-bees of the equatorial zone differ somewhat from those inhabiting more
temperate regions, in consequence of which they are assigned to distinct genera,
such as Melipoma, Trigona, and Tetrasoma. All these are rather small and sting-
less bees, making up for the absence of a special weapon of offence by a free use
of their jaws. Their brood-cells and combs resemble those of the common wasp,
each forming but a single layer; and clay and resinous substances being chiefly
used for closing the entrance of the cavities in which the nest are placed. The
characteristic transitional features in the shape of the cells, intermediate between
the simple cylindrical and the perfect hexagonal forms, have already been noticed
in the short introductory remarks. Melipoma and its allies form the connecting
link between the solitary and the hive-bees. As in the wasps, each family in the
humble-bees owes its origin to a single female which has hibernated — usually in

46 INSECTS.

some hole in the ground which it excavates for the purpose. The hive-bees, on
the contrary, swarm, that is, they send off a full-grown population under a queen
ready to enter upon the organised life of an industrial community at once. The
different forms of humble-bees are much the same as those of the hive-bees,
namely, large females ; workers or undeveloped females ; small females which are
similar to the large (or queens) in structure ; and males. One very strange habit
has been recorded and confirmed by subsequent observations. A small female is
set apart for the duty of awakening the nest every morning with her piercing
note, and has been called the " trumpeter." It seems that only those nests which
are large and have plenty of spare hands can afford this luxury.

Humble-bees, both as regards appearance and habits, are too well known to
need description. Of the two species figured in the annexed illustration, the
common humble-bee (Bombus terrestris) forms small rounded nests of carded
moss. On the other hand, the stone humble-bee (B. lapidarius) makes its
habitation in cavities among stones, where it forms an oval nest, of which only
the sides are covered with moss and grass.

F. 0, PICKAKD-CAMBKIDGE.

[Note. — The first ten pages of this chapter are by Mr. Pocock.]

CHAPTER II

Jointed Animals, — continued.

Insects, — continued.

The Flies and Fleas, — Order Diptera,

As implied by their scientific name, the typical members of the order now claiming
attention are distinguished from all other insects by the possession of but a single
pair of wings. In this case one pair of these organs has disappeared, and examina-
tion will reveal the fact that it is the front pair that is retained in full functional
importance, while the hinder pair has become reduced to a couple of short slender
club-like organs, known as halteres or balancers. From their small size it might
be supposed that these balancers were organs of but little physiological importance,
but the experiment of removing them will show that this is not the case ; for an
insect thus mutilated is thereby entirely deprived of the power of maintaining its
equilibrium and of directing its course in the air. Hence the name balancers that has
been assigned to these rudimentary wings. The mouth-parts, instead of being of
the primitive mandibulate type, are formed for purposes of piercing or sucking. In
the former kind of structure, as represented for instance in Pangonia longirostris,
one of the horse-flies (Tabanidai), these organs are composed of seven pieces, which
have been interpreted by Mr. Waterhouse as follows. The uppermost is a long
pointed instrument, the labrum. Immediately below this, and more or less
concealed by it, is an almost equally long and slender piece, which is probably the
hypopharynx. The mandibles are modified into a pair of sharp lancets, and below
them are two extremely slender instruments, which, from the presence of palpi, are
recognisable as parts of the maxilla. All these pieces lie concealed in the basal half
of the proboscis, which, for part of its length, is gutter-shaped, but afterwards
assumes the form of a tube, and is believed to be comparable to the labium. In
the gnats the mouth is formed upon the same plan, but the lancets are all more
slender. In piercing the skin the lancets only are used, the labium or proboscis
serving merely as a guide. In the flies that use the mouth for sucking — as for
instance in the blow-flies and drone-flies — the jaws are still more modified, so that
the identity of the separate pieces is difficult to establish. The most prominent part
is the proboscis, the expanding terminal lobes of which are the paraglossce of the
labium. The maxillae are represented by two scales or short stylets closely
adherent to the sides of the proboscis, and of two club-like palpi; but the
mandibles seem to have disappeared.

The only character that need be specially noticed in the wings is that they are
usually naked, — being but rarely furnished with short hairs, — and that the veins

48

INSECTS.

are almost all longitudinal, that is, they run from the base or point of attachment
of the wing to its free margin. These veins are represented in the accompanying
figures by the letters a, b, c,-d, e,f, g. The transverse veins x, y, on the contrary,
are always few in number. The shape and size of the spaces (indicated by the
numbers 1, 2, 3, etc.) circumscribed by these veins form valuable systematic
characters for distinguishing the species and genera of this order. The balancers
may be entirely exposed, as in the common daddy-longlegs, but are sometimes
concealed by a scale-like membrane as in the blue-bottle fly. In connection with
the wings may be noticed the buzzing of flies. This appears to be the result of
two distinct sounds, one produced by the rapid vibration of the wings, and the
other by the vibration of the thorax. The latter movement is the more rapid of
the two, and gives rise to the shrill note heard the moment a blow-fly is seized ;
while the former is the ordinary buzzing produced when the insect is in flight.
According to recent calculations, the thoracic vibrations in the case of one of the
humble-bee flies (Volucella) amounted to thirteen hundred per second, while those
of the wings were just one-half this number, namely, six hundred and fifty per
second. The legs possess the normal five segments ; the tarsi or feet, which are

WING OF DADDY-LONGLEGS AND OF BLOW-FLY.

also divided into five segments, being armed with two claws, and in addition, often
supplied with adhesive pads, by means of which the insects are enabled to ascend
perfectly smooth surfaces. These pads are composed of a multitude of funnel-shaped
hairs, each supposed to act as a minute sucker. Some authors assert, however,
that they secrete a sticky fluid, and that the insect maintains its hold by this
means. The antennae vary considerably in structure. In their least modified
form, as presented by the gnats and their allies, they are simple and thread-like
organs, consisting of a series of subequal segments, often modified by the presence
of long symmetrically arranged bristles, which impart to them a feather-like
aspect. In most of the members of the order the antennae are, however, curiously
constructed. The three basal segments are stout, the third being especially large
and produced into a great lobe-like plate, sometimes projecting as far as the extre-
mity of the terminal part of the organ, which frequently has the form of a plume-
like whip, the flagellurn, although sometimes reduced to a bristle. Not unf requently
the antennae differ greatly in structure according to sex. In the males of gnats, for
example, they are large and feathery, while in the females they are only furnished
with short hairs. The males and females of most of the common flies, on the
contrary, may be recognised by the development of the compound eyes. In the
former sex these organs are almost in contact on the summit of the head, while in
the latter there is a widish space between them. Rarely the sexual characters are

DIPTERA.

49

much more pronounced, as for instance in the stag-horned flies, in which the head
of the male is furnished with large branching processes, and the stalk-eyed flies, in
which the eyes in this sex are supported upon long, horizontal, immovable stalks.

Like the other higher orders of insects, flies, in the course of their development,
go through a complete metamorphosis ; the larvae — of which perhaps the commonest
are maggots and cheese-hoppers — being worm-like, and passing into a partially or
wholly quiescent pupal stage before attaining maturity. These larvae differ much
in structure in some of the families ; those of the gnats having a well-developed
head, with the antennae, mandibles, maxillae, and labium always recognisable ;
whereas in the maggots of the blow-fly the head is narrow and pointed, without
antennae, and with the mouth -parts reduced to a pair of retractile hooks, the
opposite extremity of the body being broad and square-cut. It must not be supposed,
however, that the larvae of all the members of this order are of one or other of
these two types. On the contrary, the structure varies according to habitat, and
almost every gradation is found linking the two together. Some species live in
fresh- water ponds and streams, others in the earth amongst roots of grass, others
again in rotting animal or vegetable matter, and others, like the maggots of the
warble-fly, in the stomachs of the hosts they infest. Thus the nature of their food
and surroundings is extremely varied, and that the larvae are likewise so, may be
seen by a glance at the figures in the following pages.

Upon reaching its full size the larva passes into the pupal stage. The pupa,
however, exists under two conditions. In one case, as in the gnats, it emerges from
the skin of the larva and leads an independent life of longer or shorter duration,
until the attainment of maturity ; in the others, as in the fly called Stratiomys, it
remains within the larval skin, which becomes thickened and constitutes a
protective covering for it. Again, the rupture of the larval skin for setting free
the pupa is effected in one of two ways. In the first case the opening is T-shaped,
consisting of a longitudinal split on the back behind the head, or rarely of a transverse
split between the seventh and eighth segments of the body ; in the second case a
circular split occurs behind the head, which is pushed off like a kind of cap. These
two methods of splitting of the larval skin have been used as characters for
dividing the Diptera into two suborders, those in which the pupa escapes in the
former way being termed straight-seamed flies, or Orthorrhapha, and those in which
the pupa escapes in the latter way circular-seamed flies, or Cyclorrhapha. For the
rupture of the larval skin, the pupae of the Cyclorrhapha are furnished with a bladder-
shaped excrescence on the front of the head. In the vast majority of flies the
young make their first appearance in the form of eggs. In some few cases,
however, as in the genera Sarcophaga and Mesembrina, belonging to the family
Muscidce, the young are born as active maggots ; while in the forest-flies and their
allies only one young one matures at a time, and this is retained by the mother and
nourished at her expense until it has passed into the pupal stage. The most
anomalous method of reproduction occurs in one of the gall-midges, where the
larvae themselves produce other grubs by a process of internal budding.

That flies were abundant in early Tertiary times, when they were not very
different from those that now exist, is shown by the abundance of their remains
preserved in the amber beds of the Baltic. Strata of the same age at Florissant,

VOL. VI. — 4

5°

INSECTS.

Colorado, have also yielded fossil flies. A few have been obtained from Secondary
rocks.

The Straight-Seamed Flies, — Suborder Orthorrhapha.

The first section of this suborder contains the gnats and mosquitoes (Culicidct),
daddy-longlegs (Tipulidce), true midges (Chironomidce), and fungus - midges
(Mycetophilidce). These families are sometimes spoken of collectively as the
Nematocera, or flies with thread-like antennae, on account of the length and thin-
ness of those organs, which usually consist of as many as ten or more segments.
The maxillary palpi also are elongate, and the body and limbs present, as a rule,
the type with which we are familiar in the gnats and daddy-longlegs.
Mosquitoes and The mosquitoes and gnats (Cidicidce), although often regarded as

Gnats. distinct, are in reality identical. They abound in all lands, and may
be met with in cold barren countries like Iceland and Lapland as well as in the
dense forests of tropical climes, everywhere being the plague of travellers on
account of their insatiable thirst for blood and the intense irritation caused by their
bite. It is, however, only the females that bite and suck blood, and in this

connection it may be pointed out that
no members of the Diptera sting in
the sense in which the word is used
with regard to ants and wasps ; that
is to say, the wound, although giving
rise to a sharp stinging sensation, is
inflicted by jaws, and not, as in the
case of the ants, by an organ especially
designed for the purpose placed at the
hinder extremity of the abdomen.
The annexed figure representing the
banded gnat (Cidex annulatws), a
species sometimes found in houses, and
noticeable for being .the largest British
form, is selected to illustrate the mode of life characteristic of the members of
this family. The long slender eggs, amounting to some three hundred or more,
laid by the mother in batches on the surface of a pond or ditch, give rise to worm-
like larvae furnished with a distinct head, a large somewhat squared thorax, and a
tapering jointed abdomen. Along each side of the body there is a row of bristle-
tufts, one for each segment, and the last segment is in addition produced into a
couple of tubular tails, at the extremity of which open the tracheae or breathing-
tubes. Thus equipped, the young gnat hangs suspended in the water, its heavy head
directed downwards, and the tip of its forked tail just projecting above the surface,
so that the apertures of its breathing-apparatus are in communication with the air.
Occasionally when the surface of the water is disturbed, or from any other reason
causing alarm, the larva wriggles to the bottom of the pond, soon, however, to return
to its accustomed place at the surface. During growth, the larva undergoes a series
of three moults before reaching its full size, the newly - clothed insect escaping

a. Female

BANDED GNAT.

b, Larva ; c, Pupa.

(All enlarged.

DIPTERA. 5 1

from the old skin through a longitudinal slit behind the head. At the fourth
moult emerges the pupa, which is a very different looking creature from the
larva, showing the cases for the antenna?, wings, and legs of the adult, while from
the sides of its thorax project a pair of tubes, analogous to those of the larval tail,
and like these carrying the apertures of the trachea?. By means of its jointed
abdomen the pupa jerks itself about in the water in company with others of its
kind. At the appointed time a longitudinal split occurs on the back behind the
head, and, extricating itself from its pupal-case, the adult gnat appears on the
surface of the water, where under favourable conditions its skin hardens and its
wings unfold, while it floats upon the water using its discarded clothing as a raft.
If this time of danger be successfully overcome, the insect takes wing and joins its
companions in their mazy dance ; but, before acquiring strength to do so, it is at
the mercy of every wave or gust of wind, and if once swept back into the water,
its chances of survival are small. The above-mentioned banded gnat may be
distinguished from other British species by its large size, its spotted wings, and
striped legs and abdomen. The common gnat (C. pipiens), which is often abundant
in houses in the autumn, is much smaller and without the ornaments characteristic
of its larger ally.

Travellers in the tropics are so familiar with mosquitoes that nothing we
can say can add to their knowledge of the subject. But to give those who
have been fortunate enough to avoid a practical acquaintance with them some
idea of the torments caused by these little pests, we quote the following passages
from the works of two well-known naturalists. Speaking of his sojourn at a
place on the Amazons, Bates says "at night it was quite impossible to sleep
for mosquitoes ; they fell upon us by myriads, and without much piping came
straight at our faces as thick as rain-drops in a shower. The men crowded
into the cabins and then tried to expel the pests by the smoke from burnt
rags, but it was of little avail, although we were half suffocated by the operation."
Again, Emerson Tennent writes that " of all the insect pests that beset an
unseasoned European, the most provoking by far are the truculent mosquitoes.
Even in the midst of endurance of their onslaughts one cannot but be amused by
the ingenuity of their movements; as if aware of the risk incident to an open
assault a favourite mode of attack is, when concealed by a table, to assault the ankles
through the meshes of the stocking, or the knees which are ineffectually protected
by a fold of Russian duck. When you are reading, a mosquito will rarely settle
upon that portion of your hand which is within range of your eyes, but cunningly
stealing by the under side of the book, fastens on the wrist or little finger and
noiselessly inserts his proboscis there. I have tested the classical expedient
recorded by Herodotus, who states that the fishermen inhabiting the fens of Egypt
cover their beds with their nets, knowing that the mosquitoes, although they bite
through linen robes, will not venture through a net. But notwithstanding the
opinion of Spence, that nets with meshes an inch square will effectually exclude
them, I have been satisfied by painful experience that, if the theory is not altogether
fallacious, at least the modern mosquitoes of Ceylon are uninfluenced by the same
considerations which restrained those of the Nile under the successors of Cambyses."
An interesting question arises in connection with mosquitoes as to the nature of

52 INSECTS.

the food of the vast hordes of them that frequent the tropics. It is true that the
females alone bite ; but the proboscis is a highly perfected organ for piercing and
sucking, and it might be supposed that it is extensively used for the purpose. Yet
it has been pointed out that the vast majority of mosquitoes can never taste
mammalian blood. In various places, such as parts of India for example,
mosquitoes are found in swarms in spots never visited by human beings, and in
which there are no large mammals. It has been suggested that, failing to obtain
blood, mosquitoes support themselves on the juices of plants, but no observations
in support of this have been recorded.

The daddy long-legs (Tipulidce) contain the finest species of this
division of the order ; the largest European form being the giant
daddy long-legs {Tipula gigantea), which has its wings clouded with brown, and
measures about 1^ inches in length. Much larger kinds are, however, met with in
Burma and China. The short and fleshy proboscis is not adapted for piercing, but
merely for absorbing fluids ; and the antennae are not feathery, as is so often the case
in the gnats and midges, although in the species of the genus Ctenoplwra — which are
of stouter build, and often brightly coloured black and yellow, thereby resembling
some of the saw-flies — the antennas are pectinated in the male. In this family the
eggs are laid and the larvae undergo their growth and change of form either in
water or earth. The females of two of the commonest British species (T.
oleracea and T. palwdosa) may be seen in summer and autumn flying about
meadows and depositing their eggs here and there in the soil. When hatched, the
larvae start feeding upon the roots of grass and corn, thereby doing considerable
damage to farmers and gardeners, to whom they are known by the name, " leather-
jackets."

The true midges belonging to the family Chironomidce are
nearly allied to the gnats, with which they are often confounded ; but
the mouth-parts are rarely adapted for piercing, the proboscis being short and soft.
In the genus Ceratopogon the jaws of the females are, however, lancet-shaped, and
capable of drawing blood. The little black midge that in the summer settles upon
the hands and face and inflicts a sharp prick belongs to this genus. But the best
known member of the family is the plumed midge (Chironomus plumosus), which
on summer evenings may be seen dancing in swarms along roads and lanes. Its
name has been given to this species on account of the beautiful feathery-like
antennae of the male. In connection with this species a case of luminosity has
recently been recorded. An observer in Russian Asia found on the shores of Lake
Issykkul a pumber of examples of this midge, and of an allied form belonging to
the genus Corethra emitting a phosphorescent light. Failing to discover any
luminous organ he came to the conclusion that the light was due to the presence
in the insect of multitudes of parasitic bacteria, an opinion strengthened by
the observation that the shining individuals were sluggish and never seen on the
wing.

The fungus-midges (Mycetophilidai) take their name from the

' fact that the larvae of most species feed upon fungi of various kinds.

The perfect insects, which frequent damp situations, are all of small size, and mostly

pale in colour. To this family belongs the so-called yellow-fever fly, a species of the

A COLUMN OF THE ARMY-WORM.

DJPTERA. 55

genus Sciara, which in North America is said to appear when yellow fever is
prevalent. But perhaps the most notorious species is the so-called army-worm fly
(Sciara nmilitaris), which has long attracted attention on account of the peculiar
habits of the larvae. This fly is completely black, with the exception of its legs,
which are brownish. The female, which is represented of the natural size at d, in
the accompanying illustration, and enlarged at c, is larger than the male, and has
the abdomen terminating in a pointed stylet. In the male, on the contrary, there
is at the apex of the abdomen a pair of thick two-jointed claspers, and between
these a couple of small adjacent processes, as shown at e. The extremely small
eggs are laid by the mother, to the number of about one hundred, upon soil amongst
fallen leaves on which the larvae feed. On attaining maturity, these larvae measure
nearly a quarter of an inch long, and have the form represented at a. The
black head is distinct, and furnished with eyes, and the semi-transparent body
consists of thirteen segments, some of which are furnished with lateral black
stigmata. In many countries of Europe where this insect is met with, vast hosts
of these maggots, forming a compact mass, sometimes several feet long and an inch

army-worm fly (Sciara militaris).

a, Larva ; b, Pupa ; c, Female midge ; d, The same (nat. size) ; e, End of abdomen of male ; /, A portion

of the antennae. (Magnified, except d.)

or two broad, have been seen at times creeping along at a slow pace through the
woods like a greyish serpent. The maggots crawl along, not only side by side,
but also one over the other, all adhering together by their sticky surfaces, and con-
tinually changing their position in the column. At the close of their march, when
fatigue or want of nourishment causes them to rest for a time, the larvae composing
a single train collect into a ball, which gradually diminishes in size, and finally
disappears by the burrowing into the mould of those that are lowest in the mass.
For a long while the reason for this peculiar habit remained wrapt in obscurity,
and perhaps even yet we do not understand its full significance. It has been
suggested, however, that when the supply of food for the multitude runs short, the
whole army is moved by a sudden impulse to start in search of fresh supplies. It
is almost superfluous to add that the peasantry of the countries where this strange
phenomenon is observable, failing to understand its true significance, have from
time immemorial regarded it as something supernatural, and as foretelling various
events in the future, some looking upon it as a sign of the imminence of war, others
of the destruction of their crops, and so forth. The pupa of the army-worm is

56 INSECTS.

shown at b in the figure on p. 55. This stage lasts from eight to twelve days ;

but the perfect insect is shortlived, the female surviving apparently only long

enough to pair with the male and lay her eggs.

When speaking of one of the true midges reference was made to a pathological

case of phosphorescence, but in the present family there are two instances known

of the normal occurrence of this phenomenon — not, however, in the adult insect, but

in the larval or pupal stages. The first instance is furnished by Ceroplatus sesioides,

a midge, which although not yet known to occur in England, has been met with in

several of the countries of Europe. Here the luminosity is said to resemble that of

the glow-worm, but proceeds from the entire animal, and from members of both

sexes. The larvae, which are found in small colonies on the under side of a fungus,

exhibit, when crawling in the dark, a moving streak of light, less bright than that

emitted by the pupae. The insect also shines when lying in the cocoon, so long as

its abdominal rings are still transparent and have not attained their complete

colouring. The cocoons themselves are not luminous, but allow the light to be

transmitted as through a paper lantern ; and since as a rule several of them are

situated together a more extensive glow is displayed, whereby both the cocoons

themselves and the surrounding objects are illuminated. When the insect is about

to emerge from the cocoon, the luminosity gradually diminishes, and ultimately

ceases altogether. The second instance is presented by a New Zealand midge

called Boletophila luminosa, the larva of which is known as the " glow-worm."

Here the female is luminous in all three stages of its existence, but in the male

the luminosity disappears two or three days before the emergence of the perfect

insect. The luminous organ, which is situated in the posterior part of the body of

the larva, consists of a gelatinous, semi-transparent structure, capable of extension,

contraction, and other changes of form, and, like its luminosity, is completely under

the animal's control. As to the part played by this organ in the midge's economy,

authors are at variance ; one believing that the light serves to attract small

creatures, so that they become entangled in a web of mucus, which the larva

suspends in some niche in the soil.

The gall-midges (Cecidomyidce) are minute, fragile insects, in
Gall-Midges. . te. „. . . p i •

which the wings are furnished with few veins, are often hairy, and

always fringed on the edges. From an agricultural point of view, these insects are

the most important of all the gnat-like flies, since much damage is at times done to

crops by their larvae. The most notorious is the Hessian fly (Cecidomyia destructor),

represented in its various stages in the accompanying illustration. This insect was

believed to have been introduced into North America by the Hessian troops at the

time of the War of Independence, whence the inhabitants of the United States

gave it the name by which it is now commonly known. The adult female, which

measures rather less than a tenth of an inch, is mostly of a velvety black colour,

varied with blood-red, especially on the abdomen ; while the rather larger male is

browner, with the red clearer. These flies may be observed on the wing during

the second half of April. They live, however, only for a few days, and perish soon

after laying their eggs, which amount to about eighty or a hundred. These are

placed separately or in pairs upon the leaves of the wheat-plant, and in a short time

hatch, when the larvae crawl down the leaf, reach the stalk, and burrow in it to take

DIPTERA.

57

up their abode and feed upon its tissues. This does not immediately, nor in a direct
manner, cause the death of the plant, but, weakening its stem, renders it liable to
be beaten down by wind or rain, and causes it to bear inferior corn if it reach
maturity, Towards the end of July the larvae are full grown, and pass into
the pupal stage ; while at the end of August or the beginning of September the
adults again appear and lay their eggs on winter wheat, the larvae that are hatched
from these passing the winter in the pupal state and completing their development
in the spring. Nearly allied is the wheat-midge (C. tritici), which, as its name
indicates, also attacks the wheat-plant, to which it at times does great damage.
The female lays her eggs — often in numbers — not on the leaves or stems, but in
the heart of the blossom, and their presence either entirely prevents the formation
of any seed, or renders that produced of a poor kind.

There are many other species of gall-midges which attack different kinds of
plants, such as the willow, hawthorn, etc., but lack of space forbids further refer-

DEVELOPMENT OF HESSIAN ELY.

a, Female enlarged and of natural size ; b, Abdomen of male ; c, Pupa ; d, Skin of larva forming pupa-case ; e, Larva
seen in profile (the line representing its nat. size) ; /, Larva from above (enlarged) ; g, Wheat-stalks infested with
larvue.

ence to them. One only (Miastor metroloas) demands attention on account of the
remarkable powers of reproduction of its larvae. In the majority of cases insects
are only able to reproduce their kind after attaining the adult state, the larvae
being merely the young modified for a free and active existence ; but the larvae
of this midge, which are found under the bark of trees, possess the remarkable
power of producing within their bodies living young. These grow to a certain size
at the expense of their parent, whose vitals they devour, then rupture the empty
skin and start life on their own account. The second larvae repeat the same
process of reproduction, and so the phenomenon continues through the cold months
of the year. At the beginning of the summer the process comes to an end, and
the larvae fulfil their destiny and give rise to mature insects in the ordinary
manner.

58

INSECTS.

Sand-Flies, etc.

COLUMBATSCH FLY

(enlarged).

The two families now to be mentioned have been termed the
anomalous, or fly -like Nematocera, since although their antennae are

many-jointed, they are shorter than in the foregoing families, and their limbs and

bodies instead of presenting the aspect of those of the gnats and midges, are shorter,

thicker, and closely approach in this respect those of ordinary flies. To the family

Simuliidce belong the minute " sand-flies " of the tropics, which surpass even the

mosquitoes in their venomous bite, and on account of their minute size are far more
difficult to cope with. In these insects the mouth-parts are adapted
for piercing ; and the early stages of life are passed in water. The
best known European example is the Columbatsch fly (Simulia
columbatzensis), taking its name from a village in Servia, where
it is a great pest. In fact, in all the countries irrigated by the
lower waters of the Danube, this fly, hardly larger than a flea,
abounds ; and it is said that in Hungary cattle and sheep have
been destroyed by hundreds owing to the tortures they have
suffered from these insects. The little flies creep into the eyes,

nose, and ears of their victims, and there gorge themselves with blood, driving the

poor beasts to the verge of madness by the intolerable irritation of their bites.

The second family of the group (Bibionidce) contains the well-known St.

Mark's fly (Bibio marci), a large, black, hairy, slow-flying insect, common in spring,

and taking its name from its being frequently seen in numbers on or about St.

Mark's Day. The two sexes differ greatly in many respects, the male having the

wings clear, whereas those of the female

are dusky ; again the eyes in the male are

so large that the entire head seems to be

composed of them, but in the female these

organs are small and wide apart. This

distinction, however, although not usually

in so pronounced a form, is observed

between the two sexes of many flies. The

eggs — in number amounting to about one

hundred and fifty — are laid on the ground

among vegetable or animal debris, on which

the larvae subsequently feed. In the grub

the head has neither eyes nor recognisable

antennae, but the mouth-parts are distinct ;

the body consisting of twelve segments,

each of which is surmounted by a row of bristles. After passing the winter in the

soil in an immature state, the larvae ascend to the surface in the spring, and take

on the pupal stage, from which, after about a fortnight's time, the perfect insects

emerge.
Horse-Fiies, or Although related to the gnats and midges by the nature of the

Breeze-Flies. s]^ through which the pupa makes its escape from the larval skin,

and consequently referred to the section Orthorrhapha, the flies of this family

approach those of the second section in the shortness of their antennae, and since

all the Diptera with short antennae were formerly termed the Brachycera, — as

ST. mark's fly (nat. size, with enlarged figure of
larva and pupa).

DIPTERA. 59

opposed to jSTematocera, — these and the remaining families of the suborder are
often grouped together as Orthorrhapha Brachycera. Although the horse-flies
(Tabanidce) are often termed gad-flies, the latter name is proved by Anglo-Saxon
literature to have been originally applied to the (E^r its-group of the Mascidcv.
Horse-flies are distributed all over the world, and vary but little in outward form,
usually having large, fat bodies, and being generally of a dull reddish brown
colour. They are all bloodsuckers, and the mouth-parts — which have been
described at the commencement of the chapter — attain a high degree of perfection
as piercing instruments. A common representative of the family in England is
the so-called clegg (Hcematopota pluvialis), a greyish insect which has a habit of
pitching quietly upon the hands or face, and inflicting a sharp prick almost before
the victim is aware of its presence. Fortunately, however, it is easily killed, for,
instead of taking flight, it generally stays where it has settled, and allows itself to
be crushed. A larger, though scarcer British species is the great horse-fly
(Tabanus bovinus), the female of which sucks the blood of
large mammals, such as horses, asses, and cattle. The males
always frequent flowers ; and the larvae in form and habits
show considerable resemblance to those of the daddy-long-
legs, living in the soil and feeding upon the roots of grasses.
In this way they spend the winter, reaching maturity in
May, when they pass into the pupa-stage, the fully-formed
insect appearing in June. In India these insects are known
as elephant - flies, for even the thick hide of an elephant GREAT horse-fly, with
affords no protection against their sharp needle-like jaws. ,nat# size)

Judging from the account of a resident, horse-flies are a

terrible plague in Florida. " Cows, horses, and mules have a wretched time
in the summer, when they are eaten alive, and come home with the blood running
down them. When driving, we used to spend all our time killing these soft,
fat-bodied insects, which die at the least touch — in fact, the commonest kind
never seem in any case to live more than twenty-four hours, and those which
come into the houses are always dead the next morning. Their sting is really
painful. I remember one day, when walking through the flat woods, suddenly
feeling something like a pin running into my arm, and, on looking down, found it
to be an extra big horse-fly. The arm was most tender for days after, feeling as
though badly bruised, and was so much swollen as to make it quite a difficult
matter drawing any sleeve over it. The 'coachman-fly' [doubtless one of the
family Asilidce] is said to feed on the horse-flies ; and will sit through a whole
drive on the collar, or some other part of the harness, or even on the steed itself,
in order to pounce on the insects as they settle. The curious thing is that the
horses seem to know the difference, for directly a horse-fly comes, even if it
does not sting, they become restless, tossing their heads, and lashing with their
tails, but the ' coachman ' may rest on any part of them for any length of time,
and never be interfered with, or driven off!"

The flies of the family Asilidce are generally of a somewhat

'slender build, the body being long and parallel-sided, while the legs

and wings are long and strong. All are provided with a short, powerful, piercing

6o

INSECTS.

proboscis, and prey upon insects of various kinds, often seizing and carrying oft'

butterflies, much larger than themselves. The general form of the members of

this family is shown in Fig. 1 of the annexed illustration, representing Dioctria

oelandica, a species from the island of Oeland, off the coast of Sweden, with

a shining black body, and wings of the same colour. Many species of the genus

Asilus are found in Britain, but the largest and handsomest of all is the hornet

robber-fly (A. crabroniformis), measuring upwards of an inch in length, and of a

yellowish colour variegated with black, there being four stripes of the latter colour

upon the thorax, and a broad transverse band across the base of the abdomen.

Some of the tropical members of the family are far larger, those belonging to the

genus Mydas, from South America, being scarcely surpassed in dimensions by any

member of the order. The fly represented in 2 of the illustration is the tesselated

empis (Empis tessellata), belonging to the family Empidai, the species of which

are predaceous like the Asilidce,

and resemble them in form, but

differ in certain structural details

which need not be dwelt upon.

The tesselated empis — the

largest member of the group

found in Britain — is ashy grey

in colour, and has its abdomen

ornamented with a chess-board

pattern. As Dallas expressed

it, " when paired, the females of

this and of many other of the larger species of the family are always found to

be busily engaged in sucking out the juices of some other insect. It seems

probable that the male seizes the opportunity of his intended partner being thus

occupied to make his advances ; if her mouth were free he would in all likelihood

himself fall a sacrifice to her voracity."

The families of short-horned, straight -seamed flies hitherto
Bee-Flies

considered resemble each other in the fact that the larvae live in the

earth, and feed upon the roots of grass or other vegetable matter, while the adults
prey upon other animals, whose blood they suck. But in the bee-flies (Bomby-
liidce) — so called from the likeness in hairiness and shape they present to humble-
bees — the larvae, so far as known, live parasitically on other insects, attacking
grasshoppers, caterpillars, etc., while the adults suck the juices of flowers. The
genus Bombylius is represented in England by a small number of species, although
in the tropics there are large numbers of forms. In all the thick, fat body is
covered with long yellow hairs. The wings are powerful ; and the head is furnished
with a long proboscis, which is thrust into blossoms while the insect (No. 8 on p. 65)
stays poised in mid-air, like a hawk-moth when similarly occupied. The black-and-
white bee-fly (Anthrax semiatra) is mostly of a black tint, and clothed with hair
of the same colour ; but the hairs on the front part of the thorax and abdomen take
a yellowish tinge, the wings, as shown in the illustration, being black in the basal
half but clear elsewhere. These insects may be seen on the wing in dry, sunny
spots, stopping from time to time to suck a flower, or rest upon a stone, and seeking

ROBBER-FLIES.

1, Dioctria oelandica ; 2, Empis tessellata (nat. size).

DIPTERA.

61

BLACK AND WHITE BEE-FLY, WITH PUPA-SKIN
PROTRUDING FROM COCOON OF BEE.

for the cells of solitary bees wherein to deposit their eggs. The left-hand figure
shows the cocoon of one of these bees, with the pupa-case, from which the fly on
the right has just emerged, protruding
from it. For the last family of this section
(Stratiomyidcv) the common Stratiomys
ehamcdeon may be taken as the type.
This is a rather large insect, with a short
broad abdomen, variegated at the sides
with pale spots ; the sides of the face and
the posterior part of the upper surface of
the thorax being also yellow. The antennas
are longish, and the hinder part of the
thorax is armed with a pair of spines.
The females, which may be seen on the
wing in the neighbourhood of marshes,

ponds, and ditches, lay their eggs on the leaves of water-plants, and the larvae spend
their time wriggling about in a helpless way. In these larvae the body consists of
twelve segments, is somewhat depressed, pointed at each end — though more so
towards the tail than the head — and covered with a tough blackish brown skin.
The head is small and pointed, and the retractile tail-segments are furnished at the
tip with a breathing-orifice surrounded by a circlet of barbed hairs. By means
of these the larva is enabled to suspend itself from the surface
of the water, hanging vertically downwards with the orifice
just above the water's level ; and is also able by the folding
in of the hairs to take a bubble of air below the surface when
it sinks to the bottom. The larvae feed on such particles of
matter as they find in the water ; and when ready to pass into
the pupal stage creep to the land, and take refuge beneath a
stone, or in spme other place of safety. The development of
the pupa and perfect insect takes place only in the front part of the larval skin,
A curious choice of habitat for her young on the part of some flies belonging to
this family has been recorded from Wyoming. These larvae were found in a cup-
shaped depression at the top of a cone about twenty inches high situated a few
feet from a large sulphur mound, under which the boiling water could be heard.
Through small apertures in the bottom the hot water rose and filled the cup.
It was in this that the larvae were found; and it is estimated that the tem-
perature of the water was only twenty or thirty degrees below boiling point.

female OF Stratiomys
chamoeleon.

Circular-Seamed Flies, — Suborder Cyclorrhapha.

This suborder, which is characterised by the circumstance that the pupa escapes
from the larval skin through a circular aperture formed by the pushing off of the
head-end, contains the majority of ordinary flies. It is divisible into two sections,
the first of which includes those that present the normal method of development,
the young being hatched from eggs laid by the mother, although very rarely the
eggs hatch immediately before being laid. The second embraces those in which

62

INSECTS.

Hover-Flies.

the young are retained within the parent's body, and nourished at its expense until
the pupa stage is reached. The flies of the last category are for this reason
generally called Pupipara.

The family Syrphidce includes a number of species which,
although differing considerably in external form, may be distinguished
from other members of the suborder by the presence of the so-called spurious vein
in the wing — a vein lying between the third and fourth longitudinal veins, and

crossing the short transverse vein (marked in
the figure on p. 48) which unites them. They
also bear considerable superficial resemblance,
both in colour and shape, to various bees and
wasps. The best known types are the hover-
flies (Syrphus), drone - flies ( Eristalis), and
humble-bee flies (Volucella). The hover -flies
of the genus Syrphus, which with their black
and yellow bands mimic wasps, are so named on
account of their habit of hovering in flower-
gardens in summer, darting from blossom to
blossom, and often sustaining themselves poised
in mid-air, after the manner of a hawk. The
females lay their eggs singly on leaves and
stems infested with plant-lice ; and the larvae
devour numbers of these pests, seizing them in
a most voracious manner, sucking them dry, and
rejecting the empty skins.

Like the hover - flies, drone-
flies {Eristalis) frequent flower-
gardens, where they may be seen in numbers on
various blossoms. As their name indicates, these
flies resemble honey-bees, the likeness being so
close that it is difficult to persuade an uninitiated
person that they may be handled with impunity.
The resemblance, which is enhanced by the
ceaseless twitching of the abdomen, appears
indeed to be more deeply seated than might at
first be supposed, for spiders, which recognise their prey by touch and not by sight,
treat the drone-flies with caution. Thus a blue-bottle fly placed in a web of the
field-spider was immediately and without hesitation seized and devoured, although
a humble-bee was avoided by the spider, which — evidently fearing to come to close
quarters — let out a thread, and rushing round and round its victim at a distance,
succeeded in winding it up, and then approaching, inflicted a bite which soon put
an end to the insect's struggles. When a drone-fly was thrown into the web, the
spider darted at it as before, but as soon as it touched the fly with its fore-legs,
recoiled, as if in alarm, then returning to the attack dealt with the harmless
victim just as it had previously acted with the humble-bee. The larva? of the
drone-flies live mainly in ditches and feed upon decaying organic matter, and are

Drone-Flies.

hover-fly (Syrphus seleniticus).
1, Fly ; 2, Fly hovering ; 3, Larvae devouring
plant-lice on leaf ; 4, Larva ; 5, 6, Differ-
ent views of pupa. (4, 5, 6, enlarged ;
the rest nat. size. )

DIPTERA. 63

commonly known as rat-tailed maggots, on account of the long tail-like appendages
at the hinder end of the body. With this flexible and telescopic tail, traversed by
tracheal tubes opening at its tip, the maggot is able to breathe while below the
water, by keeping the tip of its tail above the surface, where it is supported by
the rosette of hairs round the extremity. The eggs of drone-flies are also laid in
dead carcases and other refuse, and it is now believed that the legend of the ox-
born bees of the ancients is traceable to this habit of the fly, in conjunction
with its striking resemblance to the honey-bee. The belief that honey-bees are
produced by spontaneous generation from carcases of dead animals has pre-
vailed for more than two thousand years, but according to Osten Sacken, " the
original cause of this delusion lies in the fact that a drone-fly (Eristalis tenax) lays
its eggs upon the carcases of animals, that its larvae develop within the putrescent
mass, and finally change into a swarm of flies, which in their shape, hairy clothing,
and colour look exactly like bees, although they belong to a totally different order
of insects." Scarcely less interesting than the drone-flies are the species of
Volucella. These large flies (p. 65, No. 9) mimic humble-bees in colour ancl form ;
and it was long supposed that the females were thus enabled with impunity to
enter the nests of humble-bees and lay their eggs amongst those of the proper
owners. But although it is true that the eggs of the Volucella are laid and the
larvae reared inside the nests of various Hymenoptera, it has been ascertained that
the species which resemble humble-bees visit for the same purpose the nests of
wasps, to which the flies bear no particular resemblance. And it is hardly credible
that the wasps give access to the flies under the delusion that they are members
of the community, as was conceivable in the case of the bees. We are compelled
therefore to conclude that the flies are allowed by the bees and wasps to come and go
without interference for some reason apart from the resemblance that exists between
the two sets of insects. It is, of course, possible that the similarity offered by the
flies to bees and wasps is more deeply seated than was supposed, and affects such
senses as touch or smell, or some other unknown sense, but there seems no evidence
to justify this supposition ; and if the maggots of the flies feed on the larvae of the
bees or wasps, we are not yet in a position to offer an explanation of the pheno-
menon. If they play the part of scavengers, clearing the hive of waste matter, the
reason for the admittance of the flies becomes clear,

Closely resembling many of the Syrphidce in their banded coloration,
which imparts to them a wasp-like aspect, the members of the family Conopidce
may be recognised by the absence of the spurious vein in the wings, and also by
their broad heads, of which the fore-part is produced into a conspicuous promin-
ence bearing the long antennae. Like the horse-flies, the Conopidce in the adult
stage frequent flowers, but they lay their eggs in the bodies of various Hymen-
optera, like bees and wasps, and also in crickets and other Orthoptera. Here
the eggs hatch and the larvae feed upon the living tissues of their prey, and
here they undergo their metamorphosis, although they do not invariably
quit the place of their development upon the death of the victimised host.
Taschenberg, for example, found the pupa of Conops vittatus emerging from
the abdomen of a humble-bee which had been for six months in his collection. '
The Conopidce are widely distributed, and especially abundant in the tropics.

64 INSECTS.

Bates gives an account of the habits of a species which he noticed hovering over
the armies of foraging ants. These ants, he says, " are accompanied by small
swarms of a kind of two-winged fly, the females of which have a very long
ovipositor, and which belongs to the genus Stylogaster. These swarms hover with
rapidly vibrating wings, at a height of a foot or less from the soil over which the
ants are moving, and occasionally one of the flies darts with great quickness
towards the ground. I found that they were not occupied in transfixing ants . , .
but most probably in depositing their eggs in the soft bodies of insects which the
ants were driving away from their hiding-places. These eggs would hatch after
the ants had placed their booty in their hive as food for their young."

The family Musciclce embraces a large and varied assortment
of species, of which house-flies and blow - flies are well - known
examples. The characteristic structure of the wings may be seen by referring to
the figure on p. 48. The proboscis is adapted for sucking, and usually ends with
two fleshy lobes. The flagellum of the antennas is generally plumed with hairs on.
both sides, though sometimes, as in the tsetse, the hairs are restricted to one side,
while in the spiny-flies it may be naked. The relative size of the three basal
segments of the antennae varies in different genera, but usually, as in the blow -flies,
the house-flies, and the tsetse, the third segment is at least three times the length
of the second (see b in figure on p. 69, and 10 in that on p. 65). It may also be
mentioned that the upper surface of the thorax is marked with a transverse suture,
and that the feet are furnished with a pair of adhesive pads (11 in the figure on p.
65). The family is divided into several subfamilies, and these may be grouped in
two sections, based upon the presence or absence behind the wings of a membranous
scale which, when present, covers the halteres or balancers. The subfamilies that
possess this scale are termed the calypterate Muscidce ; while those that are with-
out it are in contrast called the acalypterate Muscidce. Taking the calypterate
Muscidce, we begin with the subfamily Muscince, of which the house-fly (Musca
domestica) is the typical representative. This species may be found during
summer in numbers in every house, crawling up the window-panes, flying in
companies about the middle of the room, or creeping about the table in search of
food. It is the unwelcome companion of man in every country, following him in
his travels, taking up its residence with him wherever he may choose to settle, and
resisting equally well the cold of northern latitudes and the heat of tropical climes.
For the most part, the eggs are laid and the larvae undergo their development in
excrement ; but the choice of the female does not seem to be always restricted to
matter of this sort, since she sometimes selects meal, bread, or fruit, for the
purpose. These flies are liable to the attacks of a parasitic fungus (Emjmsa
muscce) which causes their death, and in autumn it is not uncommon to find their
bodies killed by this means, with the abdomen much distended, and showing the
soft membrane between the segments. The common blue-bottle or blow-fly
(Calliphora erythrocephala) is too well known to need description. One of the
most noteworthy features connected with this fly is the extraordinary keenness of
the sense — perhaps smell, which enables it to discover the whereabouts of carcases,
however small, or of particles of meat. In these it hastens to lay its eggs ; and in a
longer or shorter time, according to temperature, the eggs hatch, and the larvae,

INSECT LIFE IN SUMMER.
1, Common Wasp ; 2, 3, Honey-bees ; 4, Hairy-legged Bee {Dasypoda) ; 5, Wasp (Pompilus) ; 6, Stone Humble-
bee ; 7, Common Humble-bee; 8, Bee-fly (Bombylius); 9, Humble-bee Fly (Volucella); 10, Spiny Fly
(Tachina) ; 11, Noctuid Moth(Anarta) ; 12, 13, Field Tiger-Beetle, crawling and flying ; 14, Wood Tiger-Beetle ;
15, Rose Beetle {Cetonia) ; 16, Dung-Beetle {Typhoeus) ; 17, Field-Cricket ; 18, Grasshopper (Stenobothrus).
VOE. vi.— 5

DIPTERA.

67

feeding upon the meat, rapidly grow until they reach maturity and pass into the
pupa stage. Many persons believe that blue-bottles arc full-grown examples
of the house-fly, and when informed that such is not the case, and that these
insects after reaching the winged stage are incapable of growth, point out that
blue-bottles vary greatly in size, and ask what may be the explanation of the
difference. The answer is, that the size of the blue-bottle in its final stage depends
upon the size of the maggot before pupating, and the size of the maggot upon
the amount of nourishment it is able to obtain before its supply of food was
exhausted. In any given case, when the supply is limited, the maggots that
are the first to hatch will get more food than those that appear later, and
in consequence, when the whole of it is exhausted, will have attained a greater
length and fatness than the others, and thus become converted into larger flies. Or,

GROUP OF FLIES AND THEIH GKUBS.

1, Blow-fly ; 2, Eggs ; 3, Larvae ; 4, Pupa ; 5, Newly-born larva of grey flesh-fly ; 6, Grey flesh-fly : 7, Adult-larva
of the same ; 8, House-fly and larva ; 9, Sharp-mouthed fly ; 10, Head of house-fly ; 11, Foot of grey flesh-
fly ; 12, Carcase of house-fly killed by fungus growth. (10, 11, enlarged ; the other nat. size.)

again, if three or four hundred eggs be laid in a dead mouse and the same number
in a dead rabbit, it is clear that in the former case the supply of food will be
smaller for each larva, and will sooner come to an end than in the latter.

The grey flesh-fly (Sarcophaga carnaria) is a handsome species, measuring in
the female half an inch in length. Seldom entering houses, it is not uncommon
in the open country, where it may be seen basking in the hot sun upon stones
or walls. Its prevailing colour is pale slate-grey, variegated on the thorax with
black bands, and the abdomen with square black spots, set corner to corner like
the squares of a chess-board. A noteworthy fact connected with this species is
that the eggs hatch within the parent before being laid, so that the young are
born alive; they feed upon decaying animal and vegetable matter. The blow-
flies belonging to the genera Calliphora and Lucilia, respectively known as
the blue-bottle and green-bottle flies, as a general rule deposit their eggs upon
dead animal matter. This, however, is by no means always the case, there being
many instances on record of the laying and hatching of the eggs upon living

68 INSECTS.

animals. Thus it is by no means uncommon for sheep to be attacked in this
way by a green-bottle fly (L. silvarum). On this subject, Mr. Reeks writes that
" these flies deposit their eggs in the wool of sheep, generally about the root of
the tail or behind the shoulders, anywhere, in fact, where the wool is most greasy.
The larvae of these flies are most troublesome to shepherds in the latter part of
May and June, until the sheep are sheared, and much later in the summer with
lambs, when they should be dipped in a preparation of arsenic and soft soap."
Toads and frogs also seem to be frequently selected as objects of attack on the part
of these flies. In one case the eggs of a green-bottle fly were laid on a toad's back,
and the larvae upon hatching migrated into its eyes. In other cases the laying of
the eggs and migration of the larvae have not been actually observed, but toads
have been found with their nostrils infested with maggots ; and it is possible that
the latter may have effected an entry from the outside, as described above. Mr.
Guthrie, who noticed the occurrence of the larvae of a blue-bottle (Calliphora) in
the nostrils of toads, writes that "it is probable that the number of toads is largely
kept under by those means. In 1872 toads were remarkably plentiful in the
neighbourhood of Tenby, South Wales, and I noticed that the disease was very
prevalent amongst them. In the following year scarcely any could be found, and
I saw none diseased." Cases are also on record of the death of lizards from
maggots of blow-flies, which testify to the extraordinary vitality of the latter.
In one instance a gecko fed on blue -bottles was found to have the whole
abdominal region greatly distended. It soon afterwards died, and on dissection its
intestines, lungs, and liver were found to be almost entirely destroyed by maggots,
whose presence was naturally attributed to eggs from gravid female blue-bottles,
which had been swallowed as food. In another case, some lizards fed on the living
maggots of the blue-bottle died in consequence of the attacks on their internal
organs by their intended food. Far more important are the cases of infection of
human beings ; the resulting sickness, which often entails great suffering, and may
end in death, being known as myiasis.

The sharp-mouthed fly (Stomoxys calcitrans), represented in 9 of the figure
on p. 65, closely resembles the house-fly in size, shape, and colouring, but may be
recognised by its sharp, horizontally projecting proboscis, and also by the flagellum
of the antennae being hairy upon one side only. It is less often seen in houses
than the house-fly, although occasionally paying them a visit, especially if there
be stables in the vicinity. By means of its proboscis this fly pierces the skin
of cattle and horses, or even of man, and gorges itself on the blood. Its eggs are
laid in the excrement of the cattle on which it feeds. Resembling Stomoxys in
habits and in the structure of its antennae and mouth-parts, the tsetse fly (Glossina
morsitans) of Equatorial Africa, although barely equalling a blow-fly in size, is
one of the greatest pests to domestic cattle, as the following accounts amply testify.
As shown in the annexed illustration, the proboscis of this fly is long and
prominent, and the antennae (6) are peculiar in that the third segment is very
long and produced almost as far as the apex of the flagellum, which is furnished
with barbed hairs along its outer surface only. Writing of the tsetse, Livingstone
says that "we had come through another tsetse district by night, and at once
passed our cattle over to the northern bank, which, though only fifty yards

DIPTERA.

69

distant, was entirely free from the pests. This was the more singular that we
often saw natives carrying over raw meat with many tsetse upon it. This insect
is not much larger than the common house-fly, and is nearly of the same brown
colour as the honey-bee. The after part of the body has three or four yellow
bars across it. It is remarkably alert, and evades dexterously all attempts to
capture it with the hand at common temperatures. In the cool of the mornings
and evenings it is less agile. Its peculiar buzz when once heard can never be
forgotten by the travellers whose means of locomotion are domestic animals, for
its bite is death to the ox, horse, and dog. In this journey, though we watched the
animals carefully, and believe that not a score of flies were ever upon them, they
destroyed forty-three fine oxen. A most remarkable feature is the perfect harmless-
ness of the bite to man and wild animals, and even calves so long as they con-
tinue to suck the cows, though it is no protection to the dog to feed him on milk.
The poison does not seem to be injected by a sting, or by ova placed beneath the

tsetse fly (enlarged).
a, Side view of head ; b, Antenna.

skin, for, when the insect is allowed to feed freely on the hand, it inserts the
middle prong of the three portions into which the proboscis divides somewhat deeply
into the true skin. It then draws the prong out a little way, and it assumes a;
crimson colour as the mandibles come into brisk operation. The previously
shrunken belly swells out, and, if left undisturbed, the fly quietly departs when it
is full. A slight itching irritation follows the bite. In the ox the immediate
effects are no greater than in man ; but a few days afterwards the eyes and nose
begin to run, the coat stares, a swelling appears under the jaw, and sometimes at
the navel ; and though the poor creature continues to graze, emaciation commences,
accompanied with a peculiar flaccidity of the muscles. This proceeds unchecked
until, perhaps months afterwards, purging comes on, and the victim dies in a state
of extreme exhaustion. The animals which are in good condition often perish
soon after the bite is inflicted with staggering and blindness, as if the brain were
affected. Sudden changes of temperature produced by falls of rain seem to hasten
the progress of the complaint, but, in general, the wasting goes on for months.
When the carcase is opened, the cellular tissue beneath the skin is found injected
with air, as if a quantity of soap-bubbles were scattered over it. The blood is
small in quantity, and scarcely stains the hands in dissection. The fat is of a

7o INSECTS.

greenish yellow colour, and of an oily consistence. All the muscles are flabby,
and the heart is often so soft that the fingers may be made to meet through it.
The lungs and liver partake of the disease. The stomach and bowels are pale
and empty, and the gall-bladder is distended with bile. These symptoms seem
to indicate poison in the blood, the germ of which enters when the proboscis is
inserted. The mule, ass, and goat enjoy the same immunity from the tsetse as
man and the game. Many large tribes on the Zambesi can keep no domestic
animals except the goat, in consequence of the scourge existing in their country.
Our children were frequently bitten, yet suffered no harm ; and we saw around
us numbers of zebras, buffaloes, pigs, palas, and other antelopes feeding quietly
in the very habitat of the fly. There is not so much difference in the natures
of the horse and zebra, the buffalo and ox, the sheep and the antelope, as to
afford any satisfactory explanation of the phenomenon." With the gradual spread of
civilisation, it might be supposed that the ravages of this pest would become lessened,
but this does not appear by any means to be the case. Writing in 1881, Mr.
Selous remarks that " nowhere does this virulent insect exist in such numbers as to
the westward of the Victoria Falls, along the southern bank of the Zambesi and
Chobi. It is usually found in great numbers near the rivers, becoming scarcer
and scarcer as one advances inland, till at a distance of a few miles it disappears,
except in some particular patches of forest. Along the water's edge they are an
incredible pest, attacking one in a perfect swarm, from daylight till sunset ; and
without a buffalo or giraffe tail to swish him off, life would be unendurable. . . .
About one in every ten bites (that perhaps touches a nerve) closely resembles the
sting of a wasp or bee, as it will cause one, when seated to spring up as if pricked
with a needle. ... I think that this plague of the tsetse flies along the Chobi
and Zambesi is due to the enormous numbers of buffaloes that frequent their
banks, as they always seem very partial to these animals. The bite of this
remarkable insect, as is well known, though fatal to all kinds of domestic
animals, is innocuous to every species of game and to man. A general belief
exists that among domestic animals, the donkey, dog, and goat are exceptions
to this rule ; but this is a mistake, for I have seen all three die from the effect
of its bites." The genus to which the common tsetse belongs is represented in
South Africa by several species, all of which seem to be similar in habits. It
ranges from Somaliland in the east and the Congo in the west, southwards as far
as the Limpopo. Fortunately it is not universally distributed throughout the
country, being somewhat local in its distribution, and inhabiting definite tracts of
land, corresponding with the beds of rivers, from which it does not appear to spread
to any great distance.

Another group of flies constitutes the subfamily Tachinince, of which the
best known examples are the spiny-flies (Tachina), so called on account of the
thickness of the bristles with which their bodies are clothed. Of stout and robust
build, these flies present a great resemblance to blow-flies and their allies, but have
the bristles of the antennae naked, or feathery only at the base, and the scales cover-
ing the balancers of larger size. The larvae, like those of the Conopidce, live
parasitically upon other insects, such as beetles, grasshoppers, and caterpillars.
The great spiny-fly {Echinomyia grossa), rather a local species, is the largest

DIPTERA.

7i

is

spixy fly (Echinomyia
ferox), WITH LARVA
AND PUPA (nat. size).

representative of the family found in Britain. It is about two-thirds of an inch
long, with a short, broad, oval abdomen ; the shining black of its body being
relieved by the reddish yellow colour of the head and the base of the wings. The
allied species (E. ferox) represented in the illustration is brownish, with the
abdomen tinted with red at the sides. Belonging to the same subfamily
the Australian fly Rutilia, remarkable among the order for
being ornamented with bright metallic green spots. By rea-
son of their external form and general colouring the flies of
the subfamily Anthoinyinoe, appear to the casual observer
to be nothing but ordinary house-flies ; but they may be
distinguished from the latter by the absence of the apical
transverse vein on the wing (marked d on the figure of the
fly's wing on p. 48). The scales, moreover, which cover the
halteres are very small, and lead up to the condition found
in those flies in which they are absent. The larva?, which

differ from those of the house and blow-flies in being covered with spines, live on
plants of various kinds, those that have attracted the most attention being the
species that attack cultivated vegetables, such as onions, cabbages, lettuces, radishes,
and the like. Those members of the family having no scales covering the balancers
and assigned to the subfamily Tryp>etince are generally of small size, many
being very obnoxious on account of the damage inflicted by their larva? on
various marketable vegetables. Of the numerous species it is only possible to
a notice a few. The first is the painted-winged as-

paragus-fly {Platyparea pceciloptera), which, as its
name indicates, has variegated wings, and attacks
asparagus. The male is smaller than the female, as
shown by the length of the lines in the figure, and
the latter sex may be recognised by the possession
of a long ovipositor, by means of which she deposits
her eggs between the scales of the head of the
asparagus. The laying takes place about the begin-
ning of May, and in two or three weeks, according
to the season, the eggs hatch, and the larva? burrow
into the stalk of the plant. In a fortnight or so
the latter reach maturity, and, after passing through the pupa stage, develop
into flies towards the end of June. Many more or less nearly allied species are
found in England and other countries, but it will suffice to indicate a few of the
more important. Of these the cherry-fly (Spilographia cerasi) and the olive-fly
(Dacus olece) devour in their larval stages the fruits after which they are named ;
while the various species of the genus Ceratitis similarly attack the orange.
Recently C. capitata was very destructive to the mandarin oranges in Malta, and
seems to have been first introduced into the island about twenty years ago. This
fly is lively and hardy, as shown by the fact that a specimen kept under a glass
shade without food maintained its activity for twelve days. When egg-laying, the
female chooses the side of the fruit exposed to the sun, where it perforates the rind
so that the larva? upon hatching start at once to devour the nutritious food. The

asparagus fly, $ male ; £ , female.
(a) Front view of head.

72

INSECTS.

infected fruit drops to the ground, and the larvae when mature pass out to become
pupee beneath the earth. Besides oranges and other acid fruits, peaches and
melons are attacked by this fly. The annexed figure represents another of these
injurious little insects (Chlorops tceniopus), a shining yellow fly variegated with

black bands. This species and its allies, which are most
destructive in the larval stage to cereals and grass,
much resemble in the cycle of their development the
above-mentioned Hessian fly. Allied to the preceding in
structure and habits are the members of the sub-family
Ortalince, containing the genus Ortalis and others. A
curious representative from the Malay Archipelago,
known as the staghorn-fly {Elaphomyia), takes its name
from the development of the sides of the head into
large branching horns. This, however, is only a sexual character, and confined to
the male. Finally, the small black fly (Piophila casei), known in the grub-stage
as the cheese-hopper, belongs to that group of Muscidce in which there are no
scales to cover the balancers.

Chlorops tceniopus, with figure
showing side view of head
(much enlarged).

Gad-Flies and Bot-Flies, — Family (Estrid^:.

The flies of this family are mostly of large size, and many present superficial
resemblance to various kinds of bees. In structural characters they are nearly
allied to house-flies, but the head is larger and broader and the mouth-parts are
reduced. In the larval stage gad-flies infest, either
as internal or external parasites, various mammals,
but since those that attack domestic cattle have
been more thoroughly studied than the others,
attention will mainly be directed to three of the
best known forms, namely, those that infest respect-
ively horses, oxen, and sheep. The horse bot-fly
(Gastrophilus equi), which resembles the honey-
bee in size, colour, and form, lays its eggs on the
skin of horses, asses, and mules, which seem to
have an instinctive dread of the insect. It has
been noticed, moreover, that the gad-fly instinctively
selects for the purpose a spot that is well within
reach of the quadruped's mouth. The reason for
this, although not at first very obvious, becomes
clear when it is understood that the larval fly can
only obtain its proper nourishment in the alimentary
canal of its host. As soon as the maggot emerges
from the egg it starts to irritate the horse's skin.
Thereupon the horse, to remove the irritation, licks
the infested spot and swallows the maggots, which
then attach themselves by means of their hook-like
mandibles to the inner wall of the stomach or

DEVELOPMENT OF HORSE BOT-FLY.

a, Adult fly ; b, Egg attached to a hair ;
c, Mature larva ; cl, Newly-hatched
larva ; e, Pupa. (All enlarged.)

DIPTERA.

73

OX WARBLE-FLY AND ITS DEVELOPMENT.

a, Fly ; b, Larva ; c, Pupa — the latter from the lower side. (All enlarged.)

oesophagus, making little excavations, and nourishing themselves by sucking up
the secreted mucus. Here in perfect security they live and grow for about
a year ; after which, when nearly full grown, they enter the intestine and pass
out of the body with the excrement. Falling to the ground, the maggots bury
themselves in the soil and enter upon the pupal stage. In favourable weather
the perfect insect is produced from the pupa in about six weeks. The ox-bot,
or ox-warble (Hypoderma bovis) deposits its eggs in the hair of the skin of
cattle, and the mag- a j

gots after hatching
burrow through the
skin and take up their
lodging in the tissues
beneath, where in
course of development
they give rise to the
large tumours known
as warbles, each of
which opens to the
exterior by means of
a small aperture. In
these tumours the
maggots remain for
ten or eleven months until practically full grown, when, quitting their host, they
fall to the ground, bury themselves, and in the course of a month or six weeks
emerge from the pupa stage as fully developed flies. The species most commonly
met with in England is not H. bovis but H. lineatum. It can be easily under-
stood from the fact that since no fewer than four hundred maggots, each grow-
ing to an inch in length, have been known to infest a single beast, the loss
occasioned by the attacks of this fly is considerable. It has been estimated,
indeed by Stratton, that in the United Kingdom alone a loss of something like
£8,000,000 per annum is sustained. The mischief begins in the summer, when
the cattle gallop about in terror in their vain efforts to escape the flies seeking
to deposit their eggs upon them. This causes waste of milk and damage to
health. Then there is the damage to the meat by the destruction of the tissue
just under the hide, resulting in what butcher's call licked meat or jelly. And
lastly, there is the evidence of tanners as to the damage to hides ; one estimate
given by a firm putting the loss on hides sold at two markets in Birmingham
during seven weeks at £545 ; while a Nottingham authority reckons the loss in that
town at £1500 to £2000 per annum. The sheep bot-fly (CEstrus ovis) lays its eggs
in the nostrils of sheep, and the maggots after being hatched pass up the nasal
passages and enter the chamber in the bones of the forehead, where they nourish
themselves on the mucus to which the irritation of their presence gives rise.
The presence of these parasites, which are seldom fewer than seven or eight at a
time, is most injurious to the infested animal, and gives rise to a sickness of a very
serious nature. At the end of about nine months the larvae reach maturity, and
making their way again into the nostrils are expelled by the sneezing of their

74

IJYSECTZ.

host, and reaching the ground bury themselves, and remain concealed until
they emerge as perfect insects from the pupal stage. The three species above
mentioned serve as types of the life-histories of the entire family, which contains
in addition a large number of genera and species infesting various kinds of
animals. Even man himself is not exempt from their attacks, and all kinds of
domestic cattle and beasts of burden, such as reindeer, camels, and elephants, are
l liable to be infested with them.

Two notices of the occurrence of
larvae in human beings were pub-
lished by John Howship in 1833.
In both cases the larvae, named
(Estrus humanus, were extracted
from tumours, the sufferer in
one case being a soldier in
Surinam, and in the other a
carpenter in Columbia. In
addition to the mammals men-
tioned, others, such as hares,
rabbits, mice, and voles, often
suffer from these parasites. Their
larvae have also been met with
in birds and frogs. Schneider,
for instance, states that two larvae much resembling those of Hypoderma were
obtained from under the skin of the head of a young sparrow, where they had
produced two large hard tumours, and Krefft has given descriptions of specimens
belonging to the genus Batrachomyia that were found living parasitically upon
Australian frogs. The larvae were situated between the skin and the flesh behind
the drum of the ear, and could be squeezed out through apertures in the skin.

LIFE-HISTORY OF SHEEP BOT-FLY.

a, Adult fly ; b, Larva from upper side ; c, Pupa from under
side (all enlarged).

Forest-Flies, — Family Hippoboscid^e.

This family brings us to the second section (Pupipara) of the Cyclorrohapha,
all the members of which are no less remarkable amongst flies for the strangeness
of their appearance than for their method of development. They are all short and
flat, with longish and powerful legs which enable them to run with great speed ;
some of them being entirely wingless, with the mouth-parts much reduced ; but in
the mode of their development they are absolutely unique in the entire order. In
the first place only a single young one at a time is produced, and this, instead of
being laid in the egg-stage, remains within the mother, nourished at her
expense by means analogous to those which obtain in the higher mammals. When
born, the young is either actually a pupa, or immediately assumes the pupa-state,
being motionless, without segmentation, and entirely protected by a horny shell,
which imparts to it the appearance of the seed of a vetch. The members of this
section, which are mostly parasitic on birds or mammals, are referable to three
families. Of these, the forest-flies are represented by several genera, all the members
of which are parasitic upon mammals or birds, and are frequently spoken of as

DIPTERA.

75

ticks. The species known from its abundance in the New Forest as the forest-fly
(Hippobosca equina) has the wings well developed. It infests horses and oxen,
usually attaching itself to those parts of the body where the covering of hair
is scanty. A second kind, known as Omithomyia avicularia, occurring, as its name
indicates, on birds of almost all kinds, also possesses a pair of fully developed
wings ; but in another species, Stenopteryx hirundinis, which is found on swallows
and about their nests, the wings are narrow and sickle-like and scarcely fitted for
flight. A fourth species, the so - called deer - tick
(Lipoptena cervi), is provided with wings upon issuing
from the pupa-case ; but after flying about for a time
the insects settle upon deer, and drop their wings by
fracturing them at the base. The last member of the
family to be mentioned, the so-called sheep-tick — which
must not be confounded with the mite of that name
— is entirely wingless from its birth. We thus get in
this family a series of forms starting with the fully-
winged forest-fly and leading through the swallow-tick
with its wings reduced in size, and the deer-tick which
can cast its wings, to the sheep-tick which has entirely
lost these organs. The second family of the group,
Nycteribiidce, contains the single genus Nycterbia, the
species of which live parasitically upon bats. All are wingless and have lost
their compound eyes, but possess the balancers. The legs are long, powerful,
and furnished with strong hooked claws, by means of which they cling to the
hosts they infest. The bee -louse (Braida caeca ; G. on p. 38), the type of the
family Braididce, is a minute, blind, and wingless insect infesting honey-bees ;
being found upon the workers, as well as upon the drones and queen, but seeming
to have a preference for the two latter as hosts.

common forest-fly (enlarged).

The Fleas, — Family Pulicidje, etc.

The fleas, which by some are regarded as an order (Aphaniptera), may be
considered to be aberrant flies ; their mouth-organs, which are adapted «f or piercing
and sucking, being modified upon the same principles as obtain in the flies. They
further resemble that group in undergoing a complete metamorphosis, but differ
from the majority of flies in being destitute of wings. The group is divisible into
two families. In the true fleas or Pulicidce the body of the adult is strongly flat-
tened from side to side, and thus, in conjunction with the smooth, hard, and nearly
naked integument, enables the insect to swiftly traverse the hairy coating of its host.
Some of the segments, however, are usually armed with strong backwardly-projecting
spines. There are no compound eyes, but each side of the head is furnished with a
simple eye ; the legs being long, strong, and fitted for leaping. The eggs are laid
about the floors of houses, kennels, etc. ; and the larvae, which are slender, worm-
like creatures, devoid of legs, but furnished with a biting mouth, live on particles of
decaying organic matter found in the dust of the places they infest. When adult,
the larva, or maggot, is said to spin a cocoon within which the pupa state is passed.

76

INSECTS.

In addition to mankind, fleas (Pulex) live parasitically upon other animals such
as dogs, cats, badgers, pigeons, fowls, moles, hedgehogs, squirrels, etc. They are,
moreover, even more abundant in tropical than in temperate countries. Tennent,
for instance, says that in Ceylon " they may be seen in myriads in the dust of the
streets, or skipping in the sunbeams which fall on the clay floors of the cottages.
The dogs to escape them select as their sleeping-places spots where a wood fire has
been kindled ; and here, prone on the white ashes, their stomachs close to the
earth, and their hind-legs extended behind, they repose in comparative coolness,
and bid defiance to their persecutors."

To the family Sarcopsyllidce
belongs the dreaded chigoe or jigger
{Sarco'psyllus penetrans) of tropical
countries. The adult female burrows
beneath the skin of the foot, and
shortly after effecting an entrance
her body becomes swollen up with
eggs, and grows to the size of a pea.
At this stage she may be easily
extracted, and as the young are not
parasitic it is seldom that serious
results ensue. According to Mr.
W. H. Blandford, " the recorded dis-
Labrum ; tribution of the chigoe extends over
ary rrr0picaj America and the Antilles,
from 30° N. to 30° S., and in late
years it has been exported in ballast to Africa, and has established itself in Angola,
Loango, and the Congo." It also occurs in British Central Africa, where quite
recently it occasioned much suffering among the natives, and, by laming the native
postmen, caused delay in the transmission of mails. As in the case of the Pulicidce,
the fleas of this family do not confine their attentions to mankind. There is, for
example, a genus known as Vermipsylla, which occurs in Turkestan, and is said to
be very injurious to cattle ; and Mr. Blandford has recently recorded a species from
Ningpo in China, found buried in the ears of sewer-rats. Speaking of the occurrence
of the jigger in Florida, a correspondent writes that " the wooden houses are built on
piles, and under them the sand is infested with jigger-fleas. All dogs are attacked
by them, and fowls and puppies frequently killed; in fact, sitting hens must
regularly have their combs covered with lard and brimstone, and insect powder
dusted over their wings, to keep them alive. These jiggers are very tiny
and black, and do not hop like Old World fleas, but, fixing themselves into the
flesh, stick there, and are most difficult to remove. An English visitor who has
once collected eggs in a Florida hen-house, on a hot June day, will for ever
remember the result."

E. I. POCOCK.

COMMON FLEA AND ITS STRUCTURE.

1, Egg ; 2, Larv.se ; 3, Pupa ; 4, Perfect insect ;
b, Labium ; c, Labial palpi ; d, Mandible ;
palpi.

CHAPTER III.

Jointed Animals, — continued.

Insects, — continued.

Butterflies and Moths, — Order Lepidoptera.

PINE HAWK-MOTH WITH LARV^l AND PUPA.

The beautiful insects comprehended in the order to which the name Lepidoptera
or scale- wings has been given are familiar to the majority of readers without any-
lengthened introductory description. The butterflies, or Rhopalocera, and the
moths, or Heterocera, though they form two distinct sections of the order, cannot
be divided by any hard-and-fast lines. They may generally be distinguished from
one another by the manner of the folding of the wings at rest, or more precisely by
the different character of the antennas. The wings of the moths, too, are locked
together by a tiny hook on the inner margin of one wing fitting into an eye on
the inner margin of the other. The butterflies never possess this curious structure.
The Lepidoptera are easily distinguishable from other orders of insects by the
four ample wings, with more or less regular veins or nervures, clothed with the
minutest, exquisitely-chiseled scales, of many shapes, and great variety of external
chasing. These scales are but modified forms of hairs, broadened out, flattened
and fashioned to cover the delicate membrane of the wing with an overlapping
armament of beauty. And it is to this wondrous sculptured dust, breaking up the

7 8 INSECTS.

rays of sunlight as it plays upon the surface of their wings, that butterflies and
moths owe their tender shades, brilliant colours, and metallic lustres. A few
butterflies are clear-winged, with scarcely any scales, such as the Ithomia of
Brazil, while the Sesiidco represent the clear-wings amongst the moths. Some
orders of insects, such as the Hymenoptera, have four membranous wings like the
Lepidoptera, but these are transparent and not clothed with scales. Others, such
as the beetles, have the upper pair horny and useless for purposes of flight, the
second pair being membranous but not scaly. The mandibles, or jaws, found in
most other four-winged insects except the Hemiptera or bugs, are replaced in the
Lepidoptera by a long tubular proboscis or suctorial apparatus, used for exhausting
the contents of honey-bearing flowers, or drawing in nutriment from less taste-
ful sources. In common with all other insects, the Lepidoptera have the body
divided into three separate sections. The head, bearing the eyes, proboscis, and
antennas ; the thorax, whence originate the legs below and the wings above ; and
lastly the abdomen, bearing along the sides the spiracles for breathing, and the
generative organs at the apex. The abdomen is never attached by a narrow stalk
or jjedicle as in the Hymenoptera. So close may their general resemblance be
to other insects, that, as is the case with the hornet clear- wing moth, none but a
naturalist could distinguish it from the common hornet. A general resemblance of
body-plan may coexist in individuals of two widely separate orders, together with
a habit of life and temperament, and likewise essential characters, wholly distinct
and different.

The Lepidoptera also resemble the insects of most other orders in
Development. .

passing through several sharply defined phases before the last and

perfect stage is attained. All first appear in the form of an egg laid by the mother
on some food-plant or tree. On hatching, the eggs give rise to a free-
walking, feeding, sleeping, and breathing larva or caterpillar; thence, after suc-
cessive changes of the skin, this passes into the quiescent, trance-like state, called the
pupa or chrysalis stage ; from this it at last emerges, at a suitable season of the year,
as the fully formed butterfly or moth. At the commencement of life the butterfly
or moth is a thing of beauty even in the egg state. Butterflies' eggs, though falling
into distinct groups of resemblance, on which even systems of classification have
been based, are as various as they are beautiful. Globular, oval, flat, barrel-shaped,
bottle-shaped, green, white, or brown, the egg is usually of a hue which renders it
not easily visible on the leaf where it has been deposited. After a time the shell
bursts, the tiny larva creeps forth, and commences feeding either on the egg-shell
or on the food lying in abundance near at hand. The larvae are long, cylindrical,
creeping, worm-like objects, with short legs, and a more or less hairy or quite
naked body. The greater number feed upon the leaves of trees, shrubs, plants, and
grasses ; while many are internal feeders, burrowing deep into the decaying hearts
of various trees. Others mine in the pith of thistles ; while many more burrow
at the roots of grass, or devour turnip-roots, to the detriment of the crops. The
larvae of the mining moths (Tinew) make sinuous channels between the upper and
lower skin of various leaves. These in the perfect form are amongst the smallest
and most lovely of all the Lepidoptera. Others, again, feed on clothing and other
woollen stuffs, gnawing ragged holes, and when the imago or perfect insect appears

LEPIDOPTERA. 79

the mischief has been done. So voracious are larvae that huge oak forests may be
in a few days swept bare of almost every vestige of foliage,
structure of The body consists of a head bearing biting mandibles for nipping

Larva. 0ff the edges of leaves, or gnawing amongst decaying timber ; a pair
of small, short antennae form appendages on either side ; and just behind three
simple eyes, or ocelli, on either side, very different from the large compound eyes
of the perfect insect. Behind the head lie eleven segments or movable rings.
Three of these, close behind the head, correspond to the thorax of the adult,
and bear the three pairs of thoracic legs, short and horny, exactly corresponding to
the three pair of legs of the butterfly or moth. The other segments bear the pro-
legs, or claspers — varying in number from one to five pairs — used for clinging to
leaves and other surfaces. In some of the moths the last pair are obsolete as legs,
and are developed into a pair of horns, supposed to be for protective purposes, as
for instance in the puss-moth. A caterpillar may thus possess sixteen legs, though
often there is not the full number.

A very curious form of larva is that producing the insects known as the
geometers, so called because of the peculiar gait of the caterpillar, which measures
out the surface over which it passes with a regular series of equal strides or loops.
Their body is long, but since there are but four pro-legs, they cannot crawl, but by
bringing up the hinder-legs advancing the head, and again bringing forward the
tail, the caterpillar spans the space to be traversed by a series of looping strides.
Hence the Americans call them " span-worms." These larvae, too, are remarkable
for their resemblance — when the head is stretched outwards — to a broken twig, a
likeness which undoubtedly secures them from many dangerous foes. Many larvae
are protected by their similarity in colour to the surrounding foliage, and it
has been supposed that the pigment from the leaves which the caterpillar eats
lends its characteristic hue to its devourer. From the moment of hatching until
the final moult, when the caterpillar enters the pupa state, it undergoes a series of
from eight to ten changes of the skin. These changes form crises in the lives of
larvae, which, at any rate in captivity, sometimes die during the process.

The stage immediately preceding that of the perfect form is
usually called, when reference is made to the butterflies, the chrysalis
state ; but in the case of the moths, the pupa state, though there is no essential differ-
ence between the two. In this strange quiescent state the wings, legs, antennae,
and proboscis of the future insect can be seen fully formed and folded tightly
within the outer covering. The only signs of vitality are given by wriggling
movements of the segmented abdomen, when the pupa is irritated. The hard
external covering is useful for resisting the attacks of predaceous insects, though
of course not securing them immunity from mice, birds, or moles, which devour
them with avidity. The chrysalis of a butterfly is usually angular and gilded.
Some are suspended simply by the tail, others have a silken girdle round the
middle to keep them fast, while some spin a very slight cocoon. The pupae of the
moths, on the other hand, are dull red, usually smooth mummy-like objects, to
which likeness the word pupa or " puppet " doubtless refers. The greater part of
these lie simply in the earth, beneath moss or bark, wherever the larva has crawled
to effect the change, without any additional covering. Others form a hard cocoon

8o . INSECTS.

of the grains of mould, to which consistency is given by means of a gummy secre-
tion furnished by the larva. Many form with this secretion a hard case, the outer
side covered with chips of the surrounding bark, which, owing to their similarity to
the surroundings, serve as a protection from observation. Others spin a silken egg-
shaped cocoon, sometimes flocculent and broken, sometimes formed of yards and
yards of silken thread, emitted from the mouth and passed over and under, across
and rOund, until the cell is complete. Amongst the more interesting of these,
cocoons is that of the emperor-moth, which forms a short tubular exit closed
against the entrance of earwigs and other insects by a circular series of fine bristles
directed outwards and converging to a point. The principle of contrivance is the
same as that employed in the manufacture of lobster-pots ; but here the process is
reversed, for in this case it admits of a ready egress but prevents any entrance.
Moths whose pupa stage is passed within an external cocoon have a double task
before them when the time is ripe for an emergence. The pupa itself — as does also
the chrysalis of butterflies — splits at the dorsal suture above the thorax, and the
moth emerges, ferreting a way through one end of the cocoon, which seems to be
softened by moisture from within, and thus escapes. The imago, or perfect insect,
having now emerged, climbs to some point of vantage, where the wings, still very
small, though completely formed, are allowed to hang downwards, expand and
harden in the air. After a few hours they are stiff and ready for use.

At no stage in their lives are lepidopterous insects free from the
Enemies. . .

attacks of enemies. In the egg-state they fall a prey to beetles and

small birds, and as larvae they are extremely liable to receive a deadly thrust with

the ovipositor (or sting) of an ichneumon. As the ichneumon-grubs grow at the

expense of their host, scarcely a tissue in the whole body may remain, save those

needful for the carrying out of life-supporting functions. And at last, when the

grubs are themselves ready to pupate, and have no further need of their host, they

finish up the rest and the larva dies — chiefly because there is nothing left to live.

The enemies of the imago, whether butterflies or moths, are numerous. Birds,

bats, dragon-flies, etc., pursue and harass them whenever they happen to meet with

them. The marvel is that any remain alive to lay eggs and perpetuate the species.

In the struggle to escape detection and capture, all unconscious

though it may be, arises the phenomenon alluded to above, and known

as protective mimicry. The kindred phenomenon of protective colouring, when the

moth or butterfly merely resembles in hue the bark, leaf, or twig on which it

rests; also protective resemblance, simply when insects take the form of objects,

such as twigs, dead leaves, bits of decayed wood, flakes of white bird-droppings ; these

are all well known. But protective mimicry means more, it implies the actual

mimicking either the form, colour, or habits of some other insect which is either

too savage or unpleasant to make it a desirable object of food ; as, for instance,

the clear-wing moths mimic gnats, bees, wasps, ichneumons, etc. Perhaps the

most curious instance is that of the Kallimas or dead-leaf butterflies of Northern

India, whose upper sides are richly coloured, while the under sides are dull brown

mottled and veined with darker colours. So conspicuous a butterfly would not

fail to fall a ready prey to foes. If it but settle for an instant, however, the

sharpest eye will not detect them. The secret lies in the colour and veining of the

LEPIDOPTERA. 81

under side. The fly settles, clings to a twig, presses the tails of the under-wings —
now folded together against it — and nothing but an old withered leaf remains
where but just now was a gaudy butterfly. A species of the genus Heliconiua, an
insect avoided by birds on account of its bitter flavour, is closely mimicked by
another butterfly of the genus Mechanitis. Though very sweet - flavoured, it
escapes unmolested amongst its less agreeable companions. The mimicry involved
in the feigning of death by many species of moths is, of course, protective. It has
even been asserted that a specimen of the magpie-moth continued to feign death
three hours after its head had been severed from the thorax,
imago or Perfect If all the dangers noted above have been passed through with

insect. impunity, in due time, at various seasons of the year, the perfect
insects — butterfly, or moth, as the case may be — will emerge. These vary in size from
12 inches or more in the expanse of the upper- wings to a quarter of an inch; — the
latter being amongst the smallest moths, or Microlepidoptera. We have remarked
that the body is divided into three distinct divisions, head, thorax, and abdomen ;
we must now shortly notice the various structures peculiar to each division. The
first division of a lepidopterous body is itself divided into four
main divisions. The occiput, next to the thorax; the epicranium,
bearing the antennas ; and, in some moths, the ocelli or simple eyes ; the clypeus,
lying in front of the epicranium, just on the mouth-parts, which latter themselves
fall into at least five or six distinct structures ; the proboscis, long, and capable of
being rolled up beneath the labrum when at rest ; the labrum, lying at the base of
the proboscis, above ; the maxillary palpi (absent or rudimentary in the butterflies) :
the labial palpi, and rudimentary mandibles, aborted in many cases, complete the
mouth structures. It is in the structure of the mouth-parts, perhaps, that the butter-
flies and moths differ most from other insects, and more especially from the fact
that the mandibles of the insects have in the Lepidoptera become modified into a
long, spirally curled, retractile proboscis, composed of three distinct hollow tubes,
soldered to each other along their inner margins. Indeed, it has much the appear-
ance of a double-barreled gun, with a third tube lying below beneath the suture of
the upper and larger pair. But it is with this latter alone that nutrition is imbibed,
and it is supposed that the other pair may furnish air in addition to that obtained
through the spiracular orifices along the abdomen. The ocelli, or simple eyes,
resembling those of the larvae ; the small eyes on the upper part of the head of
bees and other Hymenoptera, as well as those of other Arthropods, such as we find
to the number of from four to eight in the spiders, are not discoverable in the
butterflies, but are present in the moths alone. The large compound eye, composed
of numerous facets, is, however, present in both sections of the order, lying on
either side of the epicranium, just below the point of insertion of the antenna?.
Whether they see nature with these " as through a veil," or appreciate every detail
as we do ourselves, is a matter of speculation, but not easy of solution. The pair
of thread-like, many-jointed organs, which take their origin from the side of the
epicranium, just above and within the compound eyes, are amongst the butterflies,
with the exception of the family Hesperiidce, thread-like, and abruptly clubbed at
the apex. In the latter family they are gradually thickened towards the end,
which often terminates in a hook-like point. The moths, however, as their name

vol. vi. — 6

82 INSECTS.

Heterocera implies, furnish us with far greater variety in the form of the antennae ;
quite apart from the fact that they differ in both sexes of the same species, thread-
like, for instance, in the female, pectinate in the male sex, we find at least ten
different forms of antenna? amongst members of this section : — Filiform, or thread-
like, gradually tapering to a point ; fusiform, broadened from the base onwards
to the tip, which is again narrowed ; dilate, narrow from the base to about one-
third its length, then rather suddenly enlarged, and again narrowed at the tip ;
ciliate, clothed with the finest hairs ; setigerous, each joint furnished with a bristle
on either side ; setigerous and ciliate, furnished with both fine hairs and paired
bristles ; fasciculate, each joint furnished with a group or tuft of short bristles,
like a small brush ; dentate, or toothed, each joint produced into a sharp tooth-like
process at the side; lamellate, where each joint is produced at the margin into a
small plate-like prominence ; serrate, sawlike, each joint produced into a short
sharp point at the side, giving the whole antennas the appearance of a saw, the
teeth are not so long as in the dentate antennas ; 'pectinate, each joint furnished
with long plume-like hairs, or a pair of such on either side.

Thorax and its The second division of the body, like that of the Hymenoptera,

Appendages. js composed of three closely united rings, each bearing beneath a

pair of legs, while the posterior pair carry also on their upper or outer sides, each a

pair of well developed wings. The proiliorax bears the
fore-legs. The mesoihorax the mid-legs and fore-wings.
The metathorax the hind-legs and hind-wings. The
legs are not used normally for walking, but are chiefly
serviceable for clinging to objects while settling or at
rest. They do not call for any special mention; and
( are not of great account for purposes of classification,

LEFT FORE-WJXG OF A NOCTUA , - ^ butterflieg where in fly, cage o£ the mftles

MOTH. * '

a, b, c, h, indicate the normal of the three families Nymphalidai, ErycinidcB, and
position of the transverse Lyccenidce, the fore-pair are much reduced in size,

hands, a, costal margin ; / bei jn gome cages &]iao8t rudimentary.

inner margin ; a, discoidal ° ^

spot ; e, reniform spot. By far the most important structure in the eyes of

the general naturalist, though not necessarily so in
the opinion of the expert, are the beautiful membranous, scale -clad pinions.
These give the distinctive character to lepidopterous insects, and render them so
fascinating to the lover of nature. Broad and ample on the whole amongst the
butterflies, more narrowed as a rule amongst the moths — the hawk-moths for instance
— they are formed of the finest transparent membrane stretched out between the stiff
rib-like nervures, or, more properly speaking, veins, which carry the nutritive fluids
from the central system to all parts of the structure. The nerves, as custom will
persist in terming them, in the butterflies take a bow-like or ellipsoidal sweep from
the base of the wing, forming what is called the discoidal cell, whence there branch
off to the edges a series of horizontal, almost parallel, slightly divergent, nervures.
On the position of these the identification of species is most securely based, though,
in order to examine them, the insect must be spoiled as a specimen. In the moths,
on the other hand, the discoidal cell is less conspicuous, though nervures branch off
divergently from the base of the wing in a somewhat similar manner to those of

LEPIDOPTERA. 83

the butterflies. One of the most remarkable features in the wings of the
Heterocera, as distinguishtd from those of the Rhopalocera, is the existence of the
frenulum and retinaculum, briefly referred to above as the hook-and-eye arrange-
ment, with which the fore-wing is locked to the hind- wing. As already said, the
scales are modified hairs, which take a more and more perfect scale-like form
towards the centre of the wing. They lie in regularly arranged rows, over-
lapping each other, attached by a short stalk to a small forea or pit in the
membrane, to the number of many hundreds of thousands on each insect. Of
different shapes and sizes they are themselves, owing to their exquisitely sculptured
surface, objects of extreme beauty. And it is to these alone that butterflies and
moths owe their manifold tints, from the sombrest browns to the most resplendent
metallic greens, golds, and purples.

The third division of the body is composed of a series of nine

rings or segments, sometimes, as in the case of many of the moths,
tufted along the dorsal line, and also at the extremity. The spiracles, through
which the air passes to the tracheal system, lie along the sides of the abdomen,
while the organs of reproduction are placed at the extremity in both sexes.

Butterflies and moths very rarely occur in the fossil state, owing

no doubt to the delicacy of their integuments. Species of both, how-
ever, have been found in Tertiary deposits and some few in nodules of amber. The
Tertiary beds of the Florissant lake - basin of Colorado have furnished seven
species of butterflies, a dozen of moths, and one caterpillar. Two specimens of
hawk-moths are known, in one of which is well preserved the spirally-coiled proboscis.
Galleries of the leaf -mining Tineina have been preserved in leaves from the Chalk,
while other Lepidoptera, a few pearl-moths, owl-moths, goat-moths, silk-spinners,
burnets, and clear- wings, together with a few species of Vanessa and blues, have
also been recognised.

The Butterflies, — Suborder Rhopalocera.

As distinguished from the moths, the butterflies may be recognised as a general
rule by their antennae, which, as suggested by the name Rhopalocera, are slender
and abruptly clubbed at the extremity. In some cases, however, in the family of
the skippers, these organs are gradually enlarged towards the tip, which is itself
often slightly hooked. Butterflies have not, in any case the hook-and-eye arrange-
ment— the retinaculum and frenulum — by which the upper- and under- wings are
in the moths interlocked along their inner margins. The fore-legs are not always
well developed, and this is particularly noticeable in members of the male sex,
forming a reliable character in the broad subdivision of the Rhopalocera into
families. Butterflies are mostly diurnal in their habits, flying in the sunshine by
day, although a few take wing only towards evening. Their eggs and larvae differ
considerably in many respects from those of the moths, while the chrysalis is seldom
enclosed in even the finest network of silk, and in no case is wrapped in a distinct
cocoon, nor even buried beneath the earth, very rarely even close to the surface.
Usually the chrysalis is angular and blotched and speckled, with gold and silver
ornamentation; sometimes it is suspended to a branch or twig by the tail, and

84 INSECTS.

sometimes while fastened by the tail also engirdled with a line of silk around the
middle, thus tying in a position horizontal to the plane to which the larva has
attached itself. These two characters also have been used for purposes of classifi-
cation, and the suborder has been divided into Suspensi and Succincti on account
of this difference in the attachment of the chrysalis.

The following broad subdivisions of butterflies may be made : —
Firstly, those which have four perfect legs only in both sexes, the
fore-pair being rudimentary or undeveloped ; while the chrysalis is suspended by
the tail without any girdle. These include the family Nymphalidce. Secondly,
those having four perfect legs in the male, and six in the female, while the feet of the
former have no claws at their extremity ; the chrysalis being raised, resting on a
leaf or suspended. The Erycinidce represent this group. Thirdly, we have the
family of the blues (Lyccenidce), in which there are six perfect legs in the female, and
the chrysalis is suspended. The fourth group is that of the swallow-tails
(Pajnlionidce), in which both sexes possess six perfect legs, while the chrysalis is
attached by the tail and girdled by a silken thread. Lastly, the Hesperiidce agree
with the preceding as regards the legs, but the chrysalis is either attached by
threads, or enclosed in a loose cocoon. As a rule, mountainous regions are those
which abound most in butterflies, although there is a marked exception in the
case of the valleys of Tropical America.
The Fritiiiary The family Nymphalidm includes an extensive assemblage of

Group. butterflies, among which are the fritillaries, peacocks, painted ladies,
tortoiseshells, and admirals. Here also come the leaf-butterflies, purple emperors,
white admirals, Camberwell beauty, and the large high-flying blue Morphos. We
have also the subfamily Satyrince, which includes the ringlets, marbled whites,
meadow-browns, and graylings, besides many others too numerous to mention.
First we may notice, as an example of the subfamily Danainw, the butterfly
shown on the lower right-hand corner of the coloured Plate, which is known as
Euplaia harrisii. In common with several other species, it belongs to a genus of
large blue, and brown- winged tropical butterflies, in which the upper surface of the
wings is usually spotted with white. At the top left-hand corner of the same Plate
is figured the male of the orange scallop- wing (Cethosia biblis), which may be taken
as a representative of the subfamily Nymphalince. It is an inhabitant of North-
Eastern India. Its black and spiny larvae have the body banded with red and
yellow, and the head surmounted with a pair of horn-like processes.

A better - known group are the fritillaries (Argynnis), which are mostly
confined to the temperate districts of the Northern Hemisphere. In this genus,
the British silver- washed fritiiiary (A. paphia) is amongst the finest representatives
of a large number of orange-red or fulvous insects whose hind- wings on the under
side are spotted, spangled, or slashed wTith silver upon a dusted green ground.
Not uncommon throughout England, it occurs in abundance in the glades of the
New Forest, where the larva feeds on the dog-violet or wild raspberry. The dark
green fritiiiary (A. aglaia), a near relative, frequents the southern grassy downs along
the margins of the cliffs, or sports in the fern-embroidered dells of the lake-district
valleys. The high brown fritiiiary (A. adippe), a rather smaller form, whose hind-
wings, as are those of the last-named species, are spotted with silver discs, while

LEPIDOPTERA. 85

those of the silver-washed are slashed obliquely towards the lower angle. The
Queen of Spain (A. lathonia), a much rarer insect, and the two elegant little pearl-
bordered fritillaries (A. euphrosyne and A. selene) are also British. The greasy
fritillary (Melitcea aurinia) brings us to another genus, the members of which
closely resemble those of the former, but are as a rule smaller. So many figures of
all the British species have been published, that detailed description is superfluous.
The greasy fritillary inhabits low-lying marshy meadows in various localities in
England, where the larvae feed on the plantain. The heath fritillary (M. athalia)
is a very similar though very local species ; while the glanville (M. cinxia) is rare
in Britain, where it is confined to . the Isle of Wight. Many handsome species of
this genus are found in all the more northern regions of the world, but undoubtedly
the most numerous occur in the South- Western United States. The magnificent
fritillary A. childreni, which measures nearly 5 inches from wing-tip to wing-tip,
is indigenous to the Himalaya. Closely allied to the fritillaries is the map-butter-
fly (Araschnia levana) of Central Europe. It presents two very distinct forms,
one of which (A. levana) appears in the spring, the other (A. prorsa) later on in
the summer, while an intermediate form (A. porima) is also recognised. The form
known as the spring brood, figured on p. 90, is fulvous red with scattered black
spots, presenting also three white spots near the tip of the wing. The summer
brood (Fig. 4) has black wings with a red marginal line, having besides a broad
broken white bar across the wings and some white spots near the margin. The
larvae feed on the nettle in June and September. The insect, though common on
the Continent, has not been taken in England. The curiously-shaped butterfly
known as the common (Polygonia c-album), was formerly much more common in
England than it is at present. The wings are rufous with black spots, and very
strongly emarginate along the edges, and angular. The white c-shaped spots on
either hind -wing beneath render it not easily mistaken for any other British
species.

The handsome butterflies known as tortoiseshells (Vanessa) are amongst the
most widely distributed of the family, though confined to the Northern Hemisphere.
Most inhabit the more temperate regions of Europe, Asia, and America, although a
few occur in India, Ceylon, the Malay Peninsula, and Mexico, The caterpillars
feed on plants and trees, and are usually dark and spinous. The chrysalis, angular
and distinguished by its brilliant lustre, is suspended by the tail, and forms a beautiful
object. The large tortoiseshell (V. polychloros), so common in woods in England,
is usually found settling upon the trunks of trees, in summer and autumn. The
wings are rich fulvous-red, blotched and margined with black, and having a
narrow broken vein of blue just before the outer fringe. The larvae feed on the
leaves of various trees, and the chrysalis is pale pink relieved with golden
blotches. The small tortoiseshell (V. urticce), whose jet-black spiny larva feeds
on the nettle, is amongst the commonest British butterflies. The peacock
butterfly ( V. io), well known on account of the large eye - like blotches
on the upper and under - wings, is figured in all its stages in the illustration
on p. 86. The larvae also feed upon the nettle ; and the insect is found
throughout Europe and Northern Asia as far as Japan, but not in Northern Africa.
One of the handsomest, and at the same time of the rarest, of British butterflies,

86

INSECTS.

is the Camberwell beauty ( V. antiopa). Its large angular wings are rich brown above,
with a broad yellow border, enclosing on its inner margin a row of blue spots.

In the tropics the place of the preceding genus is taken by Junonia, the
members of which are not perhaps so richly coloured as the tortoiseshells. They
occur all over Eastern and Southern Asia, and are also found in North and South
America, the Oriental countries, and Africa. The caterpillars are spinous, as are
those of the two tortoiseshells. A figure of the beautiful, although dark-
coloured, Swinhoe's tortoiseshell (J.
swinhoei), is given at the lower left-
hand corner of the coloured Plate.
As an example of the genus Pyra-
meis, we may take the red admiral
(P. atalanta), which is a well-known
and richly-coloured British butterfly,
appearing in the autumn in woods,
and also in orchards where it feeds
upon the juices of decaying apples.
The large black wings with a scarlet
band across the upper, and a margin
of the same colour around the lower,
together with the group of pure
white blotches towards the tip of the
former, render it a very conspicuous
insect. When, however, the wings
are closed, the mottled black and
brown render it almost invisible.
The larvae are black and spinous,
and feed upon the common nettle ;
and the species is found all over
Europe and North Africa, North and
West Asia, and North and Central
America. In many other regions its
place is taken by some very closely
allied forms. In the painted lady
(P. cardui), of which the caterpillars
feed upon the thistle, the wings
are orange -red, black -spotted, and
black-tipped, the latter area bearing a group of white spots. It is abundant in
almost every country of the world, except the Arctic regions and South America.
Nearly allied are the porcelains (Cyrestis), which measure from 2 to 3 inches across
the wings, and are found in India, the Malay Archipelago, and a few in West
Africa and Madagascar. The sooty-veined porcelain (G. thyodamas) represented on
the coloured Plate, No. 3 from the lower right corner, is an inhabitant of
Madagascar. Of the genus Limenitis, the large white admiral (L. populi) occurs
in Central Europe, South Scandinavia, and Finland, but has not been met with in
the British Islands or in Holland. It is nearly twice the size of the English white

iSP°

GROUP OF BUTTERFLIES.

1, Peacock butterfly ; 2, The same just emerged ; 3, The
caterpillar ; 4, The chrysalis ; 5, Meadow-brown ; 6, The
caterpillar (nat. size).

LEPIDOPTERA.

87

admiral (L. Camilla), its wings being brown with a row of lunate orange marks
near the hinder margin of the lower wings. The arrangement of the white bars
on the upper wings is the same as that of the British form, but these are almost
obliterated in the male sex. The under side is of a beautiful orange-yellow colour,
broken with white, and elsewhere suffused with various shades of purplish and
bluish grey.

Closely allied to the admirals are the mango-butterflies (Euthalia), which are
almost entirely confined to India, the Malay Peninsula, and the adjacent islands.
They measure from 2 to 4 inches across the wings, and the larvae feed on the
leaves of the mango. An illustration of the black mango-butterfly (Eu. lubentina)
will be found on the coloured Plate, No. 2 from the top right corner. The
emperors (Apatura) are widely distributed over the world, except in Africa. Two
species alone are found in Europe, and these are much more brilliant insects than
the majority of the temperate species. The caterpillars are not hairy, but smooth,
and bear a pair of horns on the
head, as also does the chrysalis.
In Britain the purple emperor
(A. iris) is confined to the
southern counties of England.
Its strong purple -shot, white-
banded wings, 3 inches in expanse,
carry it with a grand sweeping
flight far above the highest oak-
trees, whence it descends, alas
for imperial predilection, to a
savoury banquet of putrid flesh,
set out in some suitable locality.
The caterpillar feeds upon the
sallow, and the perfect insect
appears in July.

Passing over many genera,
containing some of the loveliest
foreign forms, we reach the sub-
family Morphinai, in which the
caterpillars are remarkable for
their bifurcate tail and notched
or bifid head. The species of the
typical genus are giant butter-
flies of almost every hue, the
most conspicuous being of a

dazzling metallic sky-blue. Their long, satiny wings bear them aloft far out of
the reach of the collector's net. In the annexed illustration is figured, from the
under side, the resplendent ptolemy {Morplio neoptolemus). The upper side is
rich black brown, with broad transverse blue bands, shot with delicate lilac across
both wings. A pair of white spots are conspicuous on the tip of the fore-wing.

We have now to briefly notice a number of much less brightly coloured

RESPLENDENT PTOLEMY (nat. size).

INSECTS.

butterflies, many of which will be familar to most readers forming the subfamily
Satyr ince. They include the ringlets (Erebia), speckled-woods (Pararge), marbled
whites (Melanargia), meadow-browns and heaths (Epinephele and Ccenonympha),
wall-browns (Satyrus), graylings and common wood-ringlet (Hipparchia), and many
others. The caterpillars are mostty smooth, fusiform, and green, having two
horns on the head and a bifurcate tail. They feed on grasses. These butterflies fly
somewhat feebly over meadows, downs, highlands, and heath districts. As an
example of the typical genus Satyrus may be taken the common British wall-brown

(S. megcera). Here the wings are rufous
brown, spotted, speckled, and streaked
with black, having also a single eye-like
spot on the upper-wing at the tip, and
three on each lower -wing, near the
margin. As a rarity, collectors prize a
specimen in which the fore-wing spots
are bipupilled, or having twin pale
centres. Of the graylings {Hipparchia),
the British H. semele is abundant in
the heath and mountainous districts of
England. Owing to its beautifully
grey-mottled under-side, it is absolutely
invisible when settled upon rocks or
amongst the grey stones of the moorlands. The nearly allied meadow -browns
and heaths (Epinephele), which do not present a very great number of species,
are most abundant in the Mediterranean region and Western Asia. They fall
into two groups, of which E. janira is a good example of the one, while E.
tithonus, the large heath or gatekeeper, illustrates the other. The former, which
is the commonest of British butterflies, abounds in fields and meadows in the
summer, ceasing to fly the moment the sunbeams are obscured by a passing
cloud. Specimens with pale patches on the wings are valued by lovers of varieties.
The upper figures on p. 86 represent the adult and caterpillar.

wall-brown (nat. size).

Family ERYCINIDJE.

This small family, of which the characters are given on p. 86, includes species
chiefly found in the tropics. Erycina aulestes of Brazil is peculiar in having the
mid- wings produced into a tail-like projection. As an example of the family we
may take the Duke of Burgundy butterfly (Nemeobius lucina), an illustration of
which is given in the coloured Plate, No. 2 from the lower right corner. Its
brown, yellow-spangled wings once earned for it a place amongst the fritillaries.
It is, however, the sole British representative of a family whose members are so
abundant in Brazil.

The Blues and Coppers, — Family Lyc^kiDj®.

This large family, represented by many small brightly -coloured insects,
includes the blues, coppers, hairstreaks, and many others. Of the hairstreaks

LEPIDOPTERA.

89

(Thecla) the purple hairstreak (T. quercus) is a familiar example. This butterfly
has the wings brown black, shot with purple, and abounds all through Europe
wherever oak forests exist. It flits round the foliage, laying its eggs, and resting
on the leaves, and is a common British butterfly. The green hairstreak (Th. rubi)
is a smaller species than the rest, with a bright green under side, and is not
uncommon in some districts flying around bramble-bushes in summer. In the allied
genus Polyommatus, we mention the large copper (P. dispar) as one would speak

1 2 3

GROUP OF BRITISH BUTTERFLIES.

1, Large white admiral ; 2, Golden rod copper, female ; 3, Male of same ; 4, Small copper ; 5, Azure or
Clifden blue ; 6, Silver studded skipper ; 7, Duke of Burgundy.

of a departed friend, for, although formerly abundant in the fens of Cambridge-
shire and other counties, it has not been seen alive for over half a century in
Britain. The small copper (P. phleas) is, however, very abundant both in England
and on the Continent. It is shown in No. 4 of the above illustration. Of the
golden-rod copper (P. virgaurece) figures are given in Nos. 2 and 3 of the same
illustration. This species is abundant on the Continent, though unknown in
Britain. It flies in July and August, and the larva feeds on the golden-rod. The
elegant little butterflies known as blues (Lyccena) have the upper side of the

9°

INSECTS.

wings in the male sex of various shades of blue ; those of the female, on the other
hand, being usually brown, shot with a bluish or purple tinge. The larvae are
wood-louse-shaped, and feed mainly on grasses of various kinds. The common
blue (L. alexis) is one of the most abundant of British butterflies, whose white-
fringed, pale blue upper side and speckled under side, in the male, are familiar to

GROUP OF TROPICAL BUTTERFLIES.

1, Scarce swallow-tail, with larva and chrysalis ; 2, Map-butterfly, spring brood ; 3, Larvae ; 4, Summer

brood ; 5, Chrysalis of same.

everyone. The male is figured on the top right corner of the coloured Plate.
Of the many blues found in England, such as the silver-stud, the chalk-hill, the
holly blue, and the little or Bedford blue, the Clifden blue (L. adonis)— the azure
blue of many authors — is the most beautiful. It occurs not infrequently, though
locally, upon the Chalk downs of the southern coasts, and in some other localities.
A figure of the male is given in the illustration on p. 89. The wings are of a
much brighter blue than those of L. alexis.

LEPIDOPTERA.

9i

The Swallow-Tailed Group,— Family Papilionidm.

This immense family includes the giant Ornithoptera, or bird-winged butter-
flies of the tropics, the swallow-tails, Apollo butterflies, whites, brimstones, and
many others. As mentioned above, this family and the next are characterised by
the possession of six perfect legs in both sexes. The chrysalids of the present
family are suspended by the tail and girdled with a thread of silk. The largest of
the butterflies {Ornithoptera) belonging to this family measure nearly a foot across
the expanded wings. The typical members of the family are the swallow-tails
(Papilionince), which are large butterflies characterised generally by the presence of
a long tail-like process to the hind-
wings. Occasionally, however, as
in the female of Papiliomerope,
these appendages are wanting.
The two uppermost figures of the
illustration on p. 90 exhibit the
scarce swallow-tail (P. podalirius),
which is a large, strong insect with
triangular front wings, and a long
tail at the lower angle of the
hinder pair. In colour the wings
are pale yellow, with oblique trans-
verse black bars. This splendid
butterfly, although common in
Southern Europe, North Africa,
West Asia, and Persia, is only very
rarely taken in England. The larvae
feed on leaves of the sloe, apple,
plum, and other orchard trees. The
common swallow-tail (P. machaon)
was formerly very abundant in the
fen districts of England, but since
these have been drained it has
become scarcer. The four wings
are sulphur -yellow, black at their
base, with black veins, and hinder
pair of the same colour, with a band
of blue towards the margin, and a

red spot on the inner angle, close to where the tail springs. The larva feeds on the
common carrot. This species has a very wide range, occurring in the Kashmir
Himalaya. Of the royal swallow-tail (Tinopalpus imperialis), from Sikhim, a
figure is given in No. 2 from the top left-hand corner of the coloured Plate. The
females are less brilliantly coloured than the males, and have a pair of tails to each
hind-wing.

The whites, clouded yellows, orange-tips, brimstones, etc., represent the second
subfamily (Pierince) of this assemblage, in which there are no tails to the hind-

BLACK-VEINED WHITE, WITH LARVA AND CHRYSALIS.

92 INSECTS.

wings. One of the rarest British butterflies is the black-veined white {Aporia
cratcegi), shown in all stages of development in the illustration on the preceding
page. Its caterpillar feeds on the leaves of the blackthorn and other bushes. Of a
foreign representative of the group, the black-tailed sulphur (Dercas verhuelli), an
illustration is given in the coloured Plate, No. 2 from the left lower corner. It
is nearly allied to the common brimstone butterfly (Rhodocera rhamni), so
abundant in spring in English lanes and hedgerows.

The Skippers, — Family Hesperiid^.

This family differs from all the others in the broad, thick head ; the hind tibia
(with some few exceptions) being armed with two pair of spurs. There are
hundreds of species belonging to this interesting family, the majority being
indigenous to South America. Many are distinguished by their powerful build,
brilliant colours, and long-tailed hind- wings. The European species are all small,
and more or less sombre coloured, averaging about an inch across the wings. In
the puss-tailed skipper (Goniurus catillus) of Brazil, the front-wings are brown
on the upper side, with five or six pale yellow spots ; and the hind-wing also
brown, and ending in long, broad flat tails, quite as long as the hind- wing itself.
The antennse are strongly hooked at their apex. Telegonus alardus, from
Venezuela, has large wings, 2 inches across, brown, shot at their base with blue
and green, but only very slight tail-like prominences on the hinder-wings. To
Pamphila and the following genera belong all the small, quick-flying butterflies,
known as the skippers, properly so called. When at rest many of these insects
raise the upper-wings, leaving the lower ones horizontal, a habit not unknown
among butterflies of other families. The Lulworth skipper (P. actceon) is a rare,
or rather local, small brown skipper, confined in England to a few spots along the
south coast. Amongst others are P. silvanus, the large skipper, P. linea, the small
skipper, and P. lineola, the scarce small skipper lately added to the British list.
The dingy skipper belongs to another genus {Nisoniades), as does the chequered
skipper (Cyclopides). The grizzled skipper {Hesperia malvcti) is a black or brown
butterfly, with white spots on the upper side, common in England in summer. The
silver-studded skipper (H. comma) is confined to some of the midland and southern
counties of England, though abundant on the Continent. Figures of this butterfly
will be found in the illustration on p. 89, and on the coloured Plate, No. 3 from
the top right corner.

The Moths, — Suborder Heterocera.

Since limitations of space will only admit mention of a few of the genera and
species of butterflies, we pass on to the moths, in which the antennas are of many
different forms, but never distinctly clubbed. Moths are vastly more numerous —
both in genera and species — than butterflies ; and, as already observed, are for the
most part nocturnal insects. The other distinctive features having been already
mentioned, we proceed to the first family of the group.

LEPIDOPTERA.

93

Emperor-Moths, — Family 8a tueniid^e.

The splendid moths included in this family are probably amongst the most
beautiful, as they certainly are amongst the largest, of all known Lepidoptera,
ranging in size from the atlas moth (Attacus atlas), which measures a foot at
least in expanse of wing, down to the English emperor-moth, of 2 or at most
3 inches in diameter. They do not, however, vary so very much in the com-
parative beauty of their richly coloured ocellated wings. The larvee, too, are
not only of remarkable beauty, but have great commercial value ; for it is from
members of this family that China and Japan obtain vast quantities of a strong,
though less expensive silk than that produced by the ordinary silk-worm. The
former are the oak silk-moth of China (Saturnia pernyi), and its near relative
Anthercva yama-mai of Japan. In all their stages these lovely insects are
remarkable, differing widely in their general characters from the majority of

1 2

HAWK-MOTHS.

1, Eyed hawk-moth and larva ; 2, Humming-bird hawk-moth and larva. (Nat. size.)

moths. The larvae, with their clear rich green velvet bodies, deeply cleft into
separate, well-marked segments ; their rounded warts, golden, rose-coloured, and
sky-blue, emitting long sinuous hairs, the latter, sometimes enlarged at the
extremity, cannot fail to attract attention both for their unusual aspect and their
beauty. When this stage is past, and the insect reposes in the large, leathery,
sombre-brown cocoon, there is no lack of interest. The mouths of these cocoons, as
noted at the commencement of the chapter, are fashioned for the better security of the
slumbering pupa. No earwigs, beetles, or other prowling enemy can find its way
into the cocoon to destroy the inmate, though the moth can readily emerge as
soon as the outer shell of the enclosed pupa has been burst. For with a subtle
ingenuity, no less wonderful because instinctive, the larva has carefully provided

94 INSECTS.

against these contingencies. It has arranged stiff, springy bristles round the
orifice, each pointing outwards, gathered in at their tips, so that unwelcome visitors
cannot gain an entrance. But beyond all these interesting features, the perfect
insects are themselves sufficient to enlist our admiration. The enormous, strong
fore-wings with prominent anterior angles ; the rich browns, purples, and greys
in every shade and gradation; the large crescent-shaped or eye-like blotch on
both fore and hind-wing render the members of this family not easily to be
mistaken for any other lepidopterous insects. True, the eye-like blotches recall
to mind those of the peacock-butterfly, but the stout, woolly bodies, the plumose
antennas, and the feathered legs of the emperor-moths will show clearly enough
that the resemblance is but superficial, and that there is no close relationship
between them. The males fly swiftly, with a somewhat erratic flight in the
broad daylight ; and if the female, held captive in some receptacle, be placed in
the open woods, many of the former sex will eagerly gather round the cage,
and thus themselves fall victims to the net of the naturalist. There are many
varieties included in the family Saturniidce, though mention can be made of only
a few. The common emperor - moth (Saturnia carpini), one of the dwarfs of
the family, is abundant in England, where, in the heather-districts, the beautiful
emerald larva, studded with rose or golden-yellow warts, may often be discovered
wandering over some open sandy space or footpath. It is, however, at times
scarcely distinguishable as it nestles amongst the heather -stems, since the rosy
warts on the back and sides assimilating closely with the pink heather-blossoms
secure it from observation. The moth itself — smaller and darker in the male sex
— is of a deep purple brown. The fore-wings, richly variegated with greys, are
bordered with a snow-white fringe, while the hind-pair are orange margined with
brown. Both fore and hind-wings bear a black eye-like blotch, ringed with a
narrow line of blue in the centre. The tough and dry empty cocoon may often
be seen spun up amongst the heather-stems. The common emperor is found all
through Europe and in Northern and Western Asia, while a much larger form,
the peacock-moth (S. pyri), is not uncommon in Southern Europe, and has been
caught as far north as Paris. Passing on to the Chinese oak silk-moth (8. pernyi),
we find that its chief interest lies in the fact of the commercial value of its cocoon ;
a value which has not been fully recognised for more than thirty or forty years.
The Abbe Perny, from whom it derives its scientific name, was the first to
introduce it to the notice of European silk-merchants, and from him we have
a description of the method adopted by the Chinese in breeding and rearing
the larvae and winding off the silken treasure. Coppices of dwarf oak-trees are
cultivated, the earth is smoothed and cleansed with great care beneath the trees,
while attendants are always at hand- to shift the larvae from one bush to another,
or restore them to the foliage when they have fallen to ground. The best of the
cocoons from last year's cultivation are placed in a carefully regulated temperature,
and the moths are hatched off exactly at the season when the oak-leaves are
beginning to be ready for the larvae. This will be about the month of April,
when the females are laid in wicker trays where they may deposit their eggs.
Soon, within ten days, the tiny larvae creep forth and mount the oak-twigs laid
in the trays for their reception. Carried forth to the tender oak-foliage, they

LEPIDOPTERA. 95

quickly commence to feed, while the keepers are always on the watch to protect
them from insect-vermin, birds, etc., which, if permitted, would soon clear off
the whole plantation. Forty-five days at the outside, and the larvae are full-fed ;
they then spin their cocoons, pass into the pupa state, and the winding oft* of the
silken harvest begins. The largest cocoons are selected and set aside for the
breeding of larvae for another year. The rest are exposed to a high temperature
which destroys the pupae within. Boiling water — in which the earthy salts of
buckwheat ashes cleaned for this purpose have been dissolved — renders the cocoon
fit for being unwound. The silk is wound off in strands, — five, six, or eight in
number, — a single strand from each cocoon, according to the strength of thread
required. The silk thus prepared is much stronger than that from the silk-worm
moth, though it is neither so fine in texture nor so valuable. The Japanese oak
silk-moth (S. yama-mai) is closely allied to the above, and the process of culti-
vation of the insect much the same.

The Silk-Spinners, — Family BombyciDjE.

The only species belonging to this family known in Europe is the one
mentioned above as the true silk-worm moth {Bomtibyx mori). This insect has
become acclimatised in many parts of Southern Europe, where, as in China, it
is cultivated for its silken produce. The larva is itself not remarkable, save
perhaps for its resemblance to the caterpillars of the hawk-moths, with its smooth
naked skin, and short erect tail. It is, however, by far the most valuable
caterpillar yet discovered. Ages ago, from two to three thousand years before
the Christian era, — if Chinese records be reliable, — this larva was well known in
the far East, and already silk-culture was a well-established element in the
national industry. History relates how the eggs were first brought to Europe,
in the reign of the Emperor Justinian, by Persian monks, concealed in their
hollow bamboo staves ; and from these silk-culture in Europe took its origin. It
was, at any rate, carried on at Constantinople in A.D. 520. The Arabs introduced
the industry into Spain, whence it spread in the twelfth century to Sicily, and
thence to Italy and all the south of Europe. So far as England is concerned,
both James I. and George I. endeavoured to introduce the cultivation of the silk-
worm for commercial purposes, but without success. The actual mode of cultiva-
tion and preparation of the cocoon differs in no very essential feature from that
of the oak silk-moth, save that it is usually conducted under cover in well-
ventilated rooms; the wicker trays of silk- worms being arranged in rows one
above the other on light bamboo racks.

The Hawk-Moths, — Family Sphingidje.

The large moths included in this family are either diurnal or subnocturnal
in their habits, flying powerfully both in the daytime or just before nightfall.
Amongst other characteristics, the antennae are gradually thickened towards the
tip, which terminates in a hook. The fore-wings are elongate, narrow, and usually
pointed towards the apex ; while the hind-wings are comparatively of small size.

96

INSECTS.

The larvae are smooth, generally with a horn on the last segment of the abdomen.
They make no cocoon, but the pupa lies in the earth, into which the larva burrows
before the transformation takes place. As is the case with almost all, they are
protected by their colouring, which assimilates to that of the food-plant. These
line insects are divided into several subfamilies and many genera.

As the type of the subfamily Achei'ontince, may be taken the well-known
death's-head moth (Acherontia atropos), which is by far the largest of British
moths. It is a very stout, bulky insect, with strong, broad wings ; its thorax having
on the upper side a pale mark, which bears some small resemblance to a human
skull, whence it derives its scientific and trivial names. The fore-wings are dark
plum-colour, lined and spotted with the yellow ; the hind-wings yellow, with two
sinuous transverse bars of black ; and the body dark plum-colour, with black trans-
verse lines, and a yellow patch at the side of each segment. The most remarkable fact
about the moth is that it is capable of producing an audible squeak. Whether this is

ADULT AND CATERPILLAR OK SPURGE HAWK-MOTH, WITH ICHNEUMON-FLY.

produced, as was formerly supposed, by the friction of the palpi against the
coiled proboscis, or by the sudden passage of air — previously drawn into a cavity
in the stomach — through the oesophageal orifice and the proboscis, acting upon a
cleft at the extremity of the latter, is not certain. If, as has been asserted, the
squeak does not abate even on the decapitation of the moth, the air-passage theory
suffers a shock, and evidently does not entirely account for the noise. The
cleft at the end of the proboscis would perform a somewhat similar function to
that of the tongue in a penny trumpet, the reed in certain wind instruments, or
the orifice in a whistle-pipe. The handsome larva (green, with large, pale yellow,
swollen anterior segments, and yellow, black-speckled oblique stripes across the
sides), with its spinous tail, may be sometimes discovered on the jasmine and in
potato-fields. Not unfrequently, the large pupa tumbles from its friable earthen
case, when the potato crop is dug. The moth flies strongly at night, feasting
usually upon the sap oozing from the trees. It does not, however, hesitate to rob
the hive of the honey-bee, and apparently without molestation.

LEPIDOPTERA. 97

To the typical genus of the second subfamily Smerinthince belong several
well-known British species, among which the eyed hawk - moth (Smerinthus
ocellatus) is figured on p. 93 as an example. This moth is characterised by its
angular, slightly scalloped fore-wings and rose-coloured hind-wings, each bearing
an eye-like black spot, ringed with blue, near the inner angle. The larva is
delicate green, its skin rough with minute warty points, with a series of oblique

OLEANDER HAWK-MOTH. WITH LARVA AND PUPA (nat. size).

white stripes across the segments at the sides, and a short, sharp tail. It feeds
on the willow and other trees, assimilating well in colour with the leaves and their
oblique veins; while the moth, hanging with half -closed wings, closely resembles a
half-detached withered leaf. The insect is found thoughout Europe and Northern
Asia. One of the largest and most beautiful of the tribe is the oleander hawk- I
moth (S. nerii). In this species the fore- wings are rich green, veined with white, y
having towards their base a triple, transverse rose-coloured bar, whose posterior ;
vol. vi. — 7

98 INSECTS,

arm runs along the hind-margin of the wing to the thorax. The hind-wings,
thorax, and abdomen are green. ' The larva is green, with a pale band and
numerous white speckles on the sides. The first three segments are suffused
with yellow, and the third bears a large bilobate blue spot, outlined with black,
on either side. The moth occurs throughout Europe, Africa, and Southern Asia ;
but neither larva nor perfect insect are often taken in England. The caterpillar
feeds on the oleander and periwinkle in summer. Another beautiful, though small
species, is the elephant hawk-moth (Choerocampa elpenor), which typifies a third
subfamily (Chcerocampince). In this species the front-wings are green, margined
and veined with delicate rose-colour; the hind -wings black, with rose-coloured
borders ; the thorax and abdomen of the same tint of green, with a central rose-
coloured band along the back, another at the sides ; while the two last segments of
the abdomen are rose-coloured. The larva is black, with three eye-like spots at
the sides of segments three, four, and five, which are much enlarged, having also a
rose-coloured band along the sides. It feeds on fuchsia, bed-straw, willow-herb, etc.,
and is common in Europe and Northern and Western Asia in June. To the same
subfamily belong the members of the genus Deilephila, which have a world-wide
distribution, although specially common in Southern Europe ; among these, one
of the commonest on the Continent being the spurge hawk-moth (J), euphorbice).
Although the adult is rare in England, the caterpillar has been observed in some
numbers in Devonshire, feeding on the sea-spurge. The fore-wings are grey and
rose-colour in blended tints, with a large dull-green spot at their base, and an
oblique submarginal band of the same colour, besides two smaller crescent-shaped
spots towards the tip ; the hind- wings delicate rose, with black base, a deep crimson
transverse bar, followed by a narrower black one a little beyond the middle ; and
the thorax and abdomen green, the latter with white sides. The caterpillar is black,
speckled with yellow, having a dorsal rose-coloured central line, a row of yellow
spots along either side, and another below of red and yellow spots blended. It
feeds on the sea-spurge from July to September. In the figure on p. 96 the larva is
repelling the attack of an ichneumon, by ejecting noxious fluid into its face.

The pine hawk -moth (Sphinx pinastri) belongs to the typical subfamily
(Sphingince), and is a dull grey species, scarcely to be discerned as it rests on
the similarly tinted bark of the pine-trees on which the larva feeds. The moth
lays her pale green eggs upon the pine-needles, and in about a fortnight the larvae
emerge, and at once attack the needles. They have occurred in such abundance
on the Continent as to ruin whole forests of pine-trees, to the extent of many
thousand acres. Although the moth is common throughout Europe, and several
specimens have been taken in England, it is very doubtful whether a genuine
British-bred specimen has ever occurred. The larva, which changes to a pupa
beneath the earth, is green, with narrow longitudinal bands of red and white ;
these lines being naturally a great protection amidst the longitudinal lights and
shades of the pine-needles. The species is figured on p. 77.

Yet another subfamily (Macroglossincc) is represented by the humming-bird
hawk-moth (Macroglossa stellatarum), shown in the figure on p. 93. This small
and swift species, which hovers with a darting, fluttering course over flower-beds
in the sunshine, is double-brooded, and occurs almost all the year round. It has

LEPIDOPTERA. 99

often been mistaken for a humming-bird, whose flight it closely resembles, while
travellers familiar with the latter mistake the long proboscis from which the moth
derives its generic name for the slender bill of the humming-bird. The fore-
wings are dark black-brown, and the hind-wings pale copper-red. The sides of
the abdomen are blotched with white, its extremity being thickly tufted. The
larva is green or pinkish brown, with a pale stripe along the sides ; and feeds on
the lady's bed-straw. The autumn brood of larvae hibernate in the pupa state, the
perfect insects emerging in the spring.

The Prominents, — Family Notodontid.e.

These moths — which are of moderate size, with stout, hairy bodies, long, ample
wings, sometimes with a tooth-like tuft of scales on the inner margin — are very
similar in general appearance to members of the family of owl-moths {Noctuidce).
The antennae are usually pectinate in the male, and simple in the female, but in some
genera comb-like in both sexes. The larvae, which in many species assume strange
abnormal shapes and attitudes, are smooth and shiny, and without the last pair of
claspers. In some cases the terminal segment bears a pair of tail-like processes,
which can be raised or depressed, spread widely apart, or closed at pleasure. When
full-fed, the larva forms a tough cocoon, covered with chips of wood or other debris,
in which it turns to a pupa. The perfect insects fly at night, and may sometimes
be found during the day resting on the trunks of trees, palings, or other suitably
coloured objects. A common British representative is the buff- tip (Phalera buceph-
ala), although it is more often met with in the larval state than adult. Yellow-
and-black -spotted, the young larvae may be found together, feeding gregariously
upon elms and other trees. The silver-grey wings, streaked and barred with rich
browns, their tips painted with a patch of pale yellow, appear when closed, as the
moth rests on the grey bark of a tree, exactly like a short grey stick with the
top bevelled off on either side, and partially decayed. The puss-moth (Bicranura
vinula), is another common British species often found on poplar trees in the larval
state, though the perfect insect is seldom met with. The latter has white fore-
wings, tinged and marked with grey ; the thorax being spotted with black. The
compressed, globular, dull red egg is laid in the summer months on the leaves of
the poplar or sallow, and the tiny caterpillars are at first quite black, but become
greener as they grow older. When full grown, they assume, at rest, the character-
istic position represented in the accompanying illustration, whence they derive
their name of puss-moths, from some fancied resemblance to a cat. The bifurcate
tail emits thin red filaments from the apex of each branch when the larva is
irritated ; the colour being then bright green, with a red-brown or chocolate-pink
patch margined with white behind the head, narrowed and then broadened at the
sixth segment, and narrowing again to the tail. The cocoon is very tough, formed
in some crevice of the bark gnawed into a convenient cup by the strong jaws of
the larva. On the top are glued the chips thus obtained, and, with bits of lichen
added, it almost defies detection amongst the surrounding knobs and rounded bits
of bark. The species is common throughout Europe and Asia. The caterpillar of
the lobster-moth (Stauropus fagi) resembles nothing to be found in nature save

ioo INSECTS.

those of the closely allied species, as may be seen from the illustration. The moth
is found, but not commonly, throughout Europe, and the larva feeds in July upon
the oak, birch, and other trees. It is supposed that the extraordinary attitude,
with head and tail erect, has proved beneficial in warning off noxious enemies.
Another type is represented by the figure-of-eight moth (Diloba ceruleocephala),
in which the fore-wings are lead-colour, with a pair of white spots which sometimes
bear a very close resemblance to figures of eight. The larva is blue-green, with
a central yellow stripe along the back, another below the spinners, while each
segment bears a number of black warts, each with a black hair springing from the
top. Illustrations of the moth and larva will be found on p. 112. Of other forms,
the dromedary prominent {Notodonta dromedarius), the zigzag (N. ziczac), the

l 2

puss-moth (1) with caterpillar (2) in two stages of development, and (3) cocoon ; (4) caterpillar of

THE LOBSTER-MOTH.

kitten -moth (Cerwra bifida), and the swallow prominent (Pheosia dictea), are
amongst the more remarkable of the Notodontidce indigenous to England. But
we must leave this interesting group, and passing over the family Cymatophoridce,
including the peach-blossom (Thyatira batis), frosted green (Polyphloca ridens),
buff-arches (Habrosyne derasa), and others, we reach

The Clear- Wings, — Family Sesiidje.

These elegant insects — whose transparent wings, attenuated bodies banded with
yellow and red, dilate and hooked antenna?, give them no small resemblance to
members of the Hymenoptera — are diurnal in their habits, flying swiftly to and
fro in the bright sunshine. The larvae are what is called internal feeders, burrow-
ing in the trunks of various trees, or in the pith of shrubs. The pupae are armed
with little hooks, which enable them to move up and down their tunnelled
galleries. There are many species even in England, one of the largest being the
hornet clear- wing ; and so closely do this moth {Trochilium apiforme) and its near
relative (T. bembiciforme) resemble the common hornet, or perhaps more nearly
the female of one of the smaller wasps, that only a practised naturalist would be

LEPIDOPTERA.

101

able to tell the difference, and then only on a close examination. The wings are
transparent, and the body is black, striped and spotted with yellow. The moth
has a curious habit, which increases the deception, and renders its likeness to some
hostile wasp still more striking. If surprised sitting in the sunshine upon a poplar
trunk, the abdomen will be arched upwards, and the tail tapped against the bark
with a veritable — to all appearances — stinging movement. The larva burrows in

(1) HORNET CLEAR-WING, WITH LARVA AND PUPA J (2) GOAT-MOTH, WITH LARVA AND PUPA. (All nat. size.)

the wood of the poplar, and the pupa-skin may be found half out of one of the
galleries when the moth has emerged. The insect is common all through Europe
and Northern and Western Asia

Family Syntomidce.

The next family, the Tiniageriidce, must be passed over, and a brief reference
made to the moths of the family Syntomidce, which introduces uf to the well-known
burnets. The Syntomidce include small -moths with broad, triangular, spotted wings,
and body extended beyond the hind-wings. The members of this family are very
similar in general appearance to the burnets, but differ in the absence of the ocelli.
They are widely extended, and take the place of the burnets in the tropics of the
Eastern Hemisphere. Among them, the spangled white (Syntomis phegea) is a
common moth in some localities on the continent of Europe, with blue-black wings
spotted with white, as represented in the illustration on p. 111. The larva is
black, thickly clothed with hair, and feeds on the dandelion, while the perfect
insect flies, somewhat like the burnets, in the sunshine, and settles upon flower-
heads. It is not found in England, though extending through Europe to Northern
and Western Asia.

We may also notice the handmaid moth {Naclia ancilla), a very rare
species in England, but not uncommon in the woods of Southern and Central
Europe in June and July. Its larva is black, with yellow lines on the back and
sides, and it feeds on tree and rock lichens in spring.

102 INSECTS.

The Burnets, — Family Zygjenidm.

The burnets are for the most part small moths, with long, rather narrow fore-
wings, and stout bodies extending beyond the hind-wings. Their usual colour is
black, green, or dark blue, spotted with red, white, or yellow. The hind-wings are
grey, red, or similar in colour to the fore-wings, with a narrow black margin ; and
the antennae are somewhat abruptly narrowed towards the extremity. The burnets
are local, though, from their gregarious habits, abundant where they occur. The
larvae are rather compressed, tapering at both ends ; and the cocoon is long, spindle-
shaped, yellow or white, of fine shiny silk, and attached longitudinally to grass-
stems. Of the six-spotted burnet (Zygcena filipenduloe) the caterpillar feeds late
in the autumn, and hibernates until the following spring. It is short, stout,
slightly hairy, dull yellow, with two rows of black spots along the back, and feeds
on grasses of various kinds. The moth flies heavily in broad daylight, and may
often be seen, two or three together, hanging upon flower-heads in chalk-pits and
on downs by the sea. Its fore-wings are black, with metallic green lustre, having
six bright red spots placed in three pairs ; and the hind-wings are bright crimson,
with a narrow black border. The species, which is abundant in certain parts of
England, as well as on the Continent, is shown in various stages of development in
the illustration on p. 111.

The Case- Weavers, — Family Psychid^.

An interesting group of moths, although not noticeable either for size or
coloration, is that of the case-weavers. Their chief claim to notice is from the

curious habits of the larvae, which form from vegetable
debris, twigs, chips, etc., a case in which they dwell,
protruding merely the thoracic segments, with the three
pairs of legs belonging to them. Some other moths,
as for instance the genus Coleophora, also construct a
tough case of a somewhat similar nature but manu-
factured entirely of silk. Amongst other insects the
same habit of the larvae is found amongst the caddis-
flies, which creep on river-beds protected by a case of
encrusted shells, pebbles, twigs, etc. In the moths of the
present family the males alone possess well-developed
wings, the females being wormlike, and often without
antennae, legs, or wings. The phenomenon known as
parthenogenesis has been observed amongst members
of this family. The moths are mostly dull brown
insects, and the various species are better distinguished
by a comparison of the larval-cases than of the insects
psyche moth. themselves. Of the many species embraced in this

a, Male ; b, Female, larva in case ; family, one only can be described, and this but briefly.

c, Female pupa; d, Female m, . . , n , . 7 N . , ,, , .....

moth; e, Male, larva in case- iniS sPeCieS (Psyche UniCOlor) IS a dull-brOWn little

/, Male pupa. (All of nat. size.) moth, common in Central and Eastern Europe, but

GIANT SWIFT MOTH

LEPIDOPTERA. 103

not found in England. The larva of the male moth makes a larger and more con-
spicuous case, than does the grub which will produce the wingless female. The
larvae hibernate securely enclosed in their cases, which are spun on a tree-trunk or
other convenient object. In the spring the silken attachments are severed, and the
larva continues to feed until the time of pupation has arrived, when it again spins
up the mouth of the case to a tree or post, and changes within it to the pupa.
The male then emerges as a perfect moth, but the female, which is devoid of eyes,
ovipositor, or any appendages worthy of being styled antennae or legs, remains in
the larval-case even after it has emerged from the pupa. The organs for the
production of eggs are, however, complete, and parthenogenesis must, as in many
other cases, be looked upon as exceptional.

Family CossiDJE.

The moths belonging to this family, like those of several others, do not possess
any proboscis ; the antennae being pectinate in both sexes. The larvae are smooth,
and feed sometimes for several years before pupating in the centre of tree-trunks of
various kinds ; a cocoon being formed of chips of wood within which the pupa awaits
its final development. The family is typified by the goat-moth (Cossus ligniperda),
in which the front-wings are of a rich brown, streaked and mottled with darker
tints, while the hind-pair are dull brown. The larva — often known as the auger-
worm — is exceedingly destructive to forest trees, the holes which it bores in its
ravages being often half an inch, and even more, across. Its odour recalls that of
a goat, hence the name given to the moth. A large, long, flat, broad larva, flesh-
coloured, with short hairs scattered over the body, it is seldom met with, though it
sometimes may be found as it crosses a road or footpath when seeking for a suitable
place in which to spin its cocoon. It lives for over three years in the larval state,
and makes a very tough cocoon from wood chips, glued together with a gum which it
secretes. It is a native of Europe and Western Asia, generally appearing in June and
July. It is figured on p. 101.

Allied Families.

The next family (Arbelidce) must be dismissed without further remark. The
Hepialidce include the insects known as ghost-moths, one of which, the largest
British species {Hepialus lupulinus) has the wings white above and brown below,
so that when it flies in the dusk of the evening it appears and disappears in rapid
sequence owing to the practical invisibility of the dull colour of the under side, in
sharp contrast to the vivid white of the upper side. A near ally of the ghost-moth,
likewise referable to the family Hepialidce, is the splendid giant -swift moth
(Zelotypia stacyi) of Australia, which has been selected for illustration in our
coloured Plate, as being one of the finest of all moths. As the coloration and
characters of this magnificent insect are sufficiently indicated in the illustration, it
will only be necessary to give some account of its habits. Originally described
from imperfect specimens found at the Manning River and in the neighbourhood
of Newcastle, this moth was subsequently obtained in some numbers by the miners
of the latter district. Mr. A. S. Olift' writes that " as the insect is rarely found in

104 INSECTS.

the perfect, or imago condition, the larva has to be sought for and reared, — a
matter of no little difficulty, as it lives, like those of the allied genus Charagia, in
cylindrical burrows, which it makes in the interior of the stems or branches of
trees, sometimes near the surface of the ground, and sometimes at a height of fifty
or a hundred feet. By searching for these burrows, and rearing the larvae, or
pupae, when found, a considerable number of specimens have been obtained by the
miners ; but I am informed that the supply is by no means equal to the demand."

The caterpillar is long, cylindrical, and fleshy. Above its general colour is
pale yellow, with the divisions between the segments inclining to reddish brown.
The first three segments are rather bright red ; and the following segments, with
the exception of the two last, are marked with three pale spots in the middle, and
two on each side. The finely rugose head is black, as are the claws of the short
legs. In the long and cylindrical pupa each of the abdominal segments beyond
the extremities of the wing-covers is provided with a transverse serrated horny
ridge near the front margin; the seventh to the tenth segments bearing similar but
less prominent ridges ; while the hinder extremity is armed with small sharp spines.

Usually the caterpillar makes its burrows in the wood of the grey gum tree ;
but there is some doubt as to whether it does not occasionally resort to another
species of gum. Regarding the habits of the larva and pupa, Mr. Froggart writes
that the former " changes into the chrysalis in December, after having eaten off
the web in front of the bore, and placed a thick felty wad, or button, just inside
the opening of the bore ; but as soon as the chrysalis skin has become hard and
firm, it pushes the wad away, and moves freely up and down the bore, which varies
in depth from ten to twelve inches. It can move up and down the passage very
rapidly, the curious file-like rings on the lower edge of the abdominal segments
being evidently adapted to helping its locomotion. When nearly mature it has the
habit, particularly in the afternoons, of resting in the bore, with the top of its head
just level with the floor of the cross-bore, and plainly visible from the outside. The
moths appear early in March. It has been found that they never come out after
three o'clock in the afternoon ; and chrysalids under observation, if not out at that
hour, can be safely left until the next day." The next family (Callidulidce) must also
be omitted ; while the Drepanulidce may be referred to as containing the British
species Cilix spinula, and the common hooktip (Drepana falcataria), and allied
forms. Of the Thyrididce there is but one European genus (Thyris) and no British
species of this ; while the next family (the Limacodidce) is not of sufficient import-
ance to detain us.

Family LASIOCAMPID^.

The lappets, drinkers, and eggars, are well-known species included in this
large family. These moths are large, for the most part, 2 inches to 2$ across the
expanded fore-wings, others being smaller, about 1 inch only in expanse of wing,
with stout hairy bodies and strong wings. They fly rapidly in broad daylight or
at night. The larvae are clothed with soft hair, that on the sides being often
directed downwards in a tufted form. To the genus Gastropacha belong the
lappet (G. quercifolia) and the oak-eggar (G. quercus) ; the common drinker per-
taining to another genus (Odonestis), with the specific name potatoria. As examples

LEPIDOPTERA.

*°5

of the former genus we select for description the pine-lappet and the procession-
moth, both abundant on the Continent, but not occurring in England. The larvae
of both these moths spin silken cocoons. Having the front-wings grey, tinted
with different shades of brown, the pine-lappet (Gastropacha pini) is a large moth

LIFE-HISTORY OF PINE-LAPPET MOTH.

as Male; b, Female; c, Eggs; d, Larva; e, Cocoon;/, A beetle (Calosoma) attacking larva; g, Larva of Calo-
soma; h, An ichneumon laying its eggs in the pupa; i, Small parasites emerging from their cocoons on the
remains of the larva which they have devoured.

measuring from 2| inches across the wings. The larvae are ashen grey, with a
dorsal row of dark blotches, a lateral brown stripe, and a pair of blue transverse
bands on the third and fourth segments. This handsome larva is often very destructive

io6

INSECTS.

to the pine-forests, where it feeds upon the needles of the trees, and sometimes
appears in overwhelming numbers. In coping with the enormous quantity of
caterpillars of this moth which devastate the district on these occasions, man is
materially assisted by other creatures. Thus, a tree-frog ascends and feeds upon
the larvae ; ichneumons of different species sting, and thus destroy, thousands ; an
internal fungus establishes itself in the caterpillar, with the same result; and,
lastly, a beetle and its larvae, which are represented in the illustration, render no
small assistance in clearing off the pest. The caterpillars are hatched in the autumn
and hibernate, remaining throughout the winter in the moss at the foot of the trees.

processiox-jioth {Gastropacha processioned). 1, Male ; 2, Single hair of the larva ; 3, Segment of larva;

4, The pupa ; 5, The cocoons of several larv;e spun up together. (Nos. 2 and 3 enlarged.)

The main illustration represents the migration of the larvae in orderly procession.

In this state, coiled round in a spiral form, they may be frozen quite stiff, yet
on the return of spring they regain vitality, and climb the trees in search of their
usual provender. The red-brown cocoon is spun sometimes between the needles
of the tree, as represented in the illustration, or else beneath some semi-detached
piece of bark. In the procession-moth (Gastropacha processicmea) the fore-wings
are yellow -grey, with a glossy sheen, and dark indistinct oblique transverse bars.
The larvae are hairy with a blue-black back, pale sides, and red or grey warts on
each segment. At night the caterpillars march out to feed in a regular orderly

LEPIDOPTERA.

107

LACKEY-MOTH.

Perfect insect, eggs, larvae, and cocoon.

procession, as represented in the illustration. One, the leader, marches at the

head, followed by two, three, and so on, forming a wedge-shaped column. They

ascend the oak-trees and return again in the same manner to their resting-place.

They also spin their cocoons together as in Fig. 5 of the illustration. The species is

common throughout Central and Southern Europe in August and September. As

our last representative

of the family we take

the lackey-moth (Clis-

iocampa neustria),

which is common in

England and all through

Europe and North and

Western Asia during

July and August. The

fore - wings are dull

ochre-brown, with two

oblique transverse

brown bars. The eggs

are laid by the female

in the late summer in

a firmly attached ring

round some small twigs,

as shown in the illustration. The larvae hatch in the spring following, and are

brown with blue, white, red, and yellow longitudinal stripes ; all feed on the leaves

of the pear and other fruit trees, and spin a long sulphurous yellow cocoon amongst

the leaves.

Family LymaNTBIID^E.

This group includes a number of moths in which the males have the antennas
strongly pectinated, while in the case of the genus Orgyia the female is wingless.
None possess a proboscis. The larvae are hairy, and clothed with long thick tufts,
springing in some places from wart-like prominences. The hairs of the larvae are
woven into the cocoon, and if they come in contact with the skin cause great
irritation. In this family are included some well-known British moths, such as the
vapourer (Orgyia antiqua), the pale tussock (Dasychira pudibunda), the black
arches (Lymantria monacha), the gold-tail and brown-tail, the satin-moth, and

many others. In the gipsy-moth (Ocneria
dispar) the wings of the male are smoky
black, while those of the female are grey;
the appearance of the two sexes being very
different indeed. The larvae feed on various
trees, and though very rare in England are
sometimes so abundant on the Continent as
to prove very destructive to all kinds of
trees and herbage ; stripping even maize and
hermaphrodite gipsy-moth. millet-fields, orchard, and vegetable produce.

io8

INSECTS.

The cocoon is formed in a few folded leaves spun together with silk or in
a crevice in the bark. The single figure represents an hermaphrodite specimen

BLACK-ARCHES MOTH.

1 and 2, Males ; 3, 4 and 5, Females ; 6, Young larvae ; 7, Full-grown larvae ; 8, Pupa. (Nat. size.)

LEPIDOPTERA.

109

of this insect. Its wings, antennae, and the dark half of the thorax and abdomen
on the left side are of the colouring and form peculiar to the male, while those
on the right resemble the form peculiar to the female. The illustration on
p. 108 illustrates the stages in the development of the black -arches moth,

PALE TUSSOCK MOTH, WITH ITS CATERPILLAR AND PUPA (nat. size).

which is not altogether abundant in England but much more commonly met
with on the Continent. Indeed, so abundant is it at times that it causes
great injury to forest trees. In Prussia, Lithuania, and Poland, the havoc has

brown-tail moth. 1, Male ; 2, Female laying eggs ; 3, Larvae ; 4, Pupa ; 5, Antennae of male ; 6, Wing-scales ;
7, gold-tail moth (Porthesia auriflua) larvae ; 8, Separate plumose hairs ; 9, Segments of larvae. (5, 6, 8, 9,
enlarged. )

been particularly severe. In 1863 the moth appeared in countless thousands,
driven up as a regular insect storm by the south wind. Within a few hours the
moths spread over the whole country side, buildings were completely covered

INSECTS.

by them, and the very surf of the lake assumed a more snowy whiteness, due to the
colour of the hosts of moths drowned in the waters. The woods seemed as
though visited by a violent snowstorm, so thickly were the insects massed in the
foliage. In 1852 whole forests were felled, in order if possible to be rid of the
pest. The trunks were searched for eggs, and every tree-trunk in an area of
fourteen thousand acres was examined. Often an ounce of eggs would be taken
from a single tree, and, at the computation of thirty thousand to the ounce, we
get, at one hundred trees per acre, upwards of thirty hundred million larvae at
work upon the trees in that area when the eggs hatched. Spotted woodpeckers,
finches of all kinds, the larva of a longicorn beetle, Clerus, all assisted in the work
of destruction. Yet, in spite of all this, it needed a hundred labourers with twenty

foremen to carry out the destruction
of the young larvae hatched from
eggs which were overlooked in a
single acre of forest. The ground
too, after the season was over, was
white with the cocoons of countless
thousands of Ichnewmonidce, so that
millions of the larvae can never, from
the attacks of these alone, have
reached maturity. The pale tussock-
moth (Dasychira pudibunda) derives
its trivial name from the tufts or
tussocks of hair so noticeable a
feature in the hairy clothing of the
larvse. The fore-wings are grey with
a smoky transverse bar. The larva is
green with a transverse bar of velvet black between the segments from five to eight.
Each of these segments bears a thick squarely truncated tuft of upright yellow
hairs, and the last carries a long tail or brush of hair. The species is abundant in
England and all Europe. In the brown-tail moth (Porthesia chrysorrhoea) the
wings are snowy white, while the body is white with a brown tufted tail in the
male, which in the female is much larger. The hairs of the tuft are deposited upon
the eggs as a covering when laid by the female. The larva is short, thick, and
black, with four rows of spiny tubercles along the sides. It is common in Great
Britain and also on the Continent. Very similar to the last is the gold-tail
(Porthesia auriflua), but the front -wings are dotted with three or more black
spots, while the tuft at the extremity of the abdomen is formed of golden hairs
instead of brown. The larva has rows of tubercles along the sides, whence issue
numerous hair-like bristles. Each of the tubercles of the second row bears tufts of
white hair. The third row is bright red. A bright vermilion double stripe runs
along the back, while between the tenth and eleventh segments is a cup-like scarlet
protuberance. The satin-moth (Porthesia salicis) is another well-known member
of the family, taking its name from the white satiny wings; the antennae and
thorax being also white, and the body black, clothed with white hairs. The larva
feeds on the poplar, and is abundant in England and throughout Europe.

satin moth {Porthesia salicis), with larvae and pupa.

An ichneumon is depositing its eggs in one of the larvse, while
another is just emerging from the pupa.

LEPIDOPTERA.

The Tiger-Moths, — Family Arctiidje.

Two families, including many tropical species, come between the Lymantriidce
and the Arctiidce, namely, the Pterothysaniclce and the Hypsidcc. The forms
included under the name Arctiidce, embracing a number of beautiful moths,
such as the tigers, ermines, etc., are usually divided into four subfamilies, the
Arctiince, represented by the tigers, properly so called, the Lithosiince including
the footmen, the Nolince, and the Nycteolince. Of the first subfamily, the most
familiar member is the common tiger-moth (Arctia caja), which in summer comes
freely to light. The fore-wings are rich chocolate-brown with cream-coloured
markings ; and the hind-wings crimson with black blotches. Two very beautiful

1, COMMON TIGER-MOTH

2 and 3, Varieties of same ; 4, Larva of same ; 5, six-spot burnet ; 6, Its larva ;
7 the spangled white. (Nat. size.)

varieties of this exceedingly variable moth are figured in the accompanying
illustration. The larva is the well-known woolly bear, a large swiftly moving
caterpillar, clothed with long bristling black hairs, red at their base, which spins a
loose web, thickly covered with the hairs with which it is clothed, and turns to a
naked pupa.

The Owl-Moths,— Family Noctuid^:.

Passing over the family Agaristidce, we reach the true night-flying moths,
now included in the family Noctuidce. This enormous group has been subdivided
into no less than ten subfamilies. Of the first subfamily (Trifeince) the rustic
shoulder-knot (Hadena basilinea) is a well-known example. In this moth the
fore-wings are grey-brown, with a central transverse darker band, and a distinct
dark streak at the base of the wing. The larva is grey-brown, with three white
lines along the back. It feeds on various kinds of grass, and often on the ears of

INSECTS.

wheat devouring the corn grains. As its scientific name implies, the pine-moth
{Trachea pinipercla) is in the larval state very destructive to pine-trees in seasons
favourable to a great increase in their number. When young, they spin together
the needles of the pines, and often drop themselves by a thread to various points,
whither they may feel inclined to descend. The pupa may be found in plenty
amongst the moss which so often carpets the ground in pine-woods. The moth
itself is cinnamon-red, with white blotches and spots. It is common in England
and on the Continent. A figure of the moth and larva is given on p. 105. The
merveil du jour (Diptkera orion), figured in the illustration below, indicates
another subfamily (Acontince). It has the fore-wings of a pale green, with
longitudinal white stripes, and three broken transverse black bars, the fringe
being spotted with black and white. The egg is described as resembling a sea-
urchin, having twenty sinuous ribs. The larva is black, with large primrose
yellow spots on the back of the third, fifth, and eighth segments. It feeds in

1, MERVEIL DU JOUR, WITH LARVA ; 2, RUSTIC SHOULDER-KNOT, WITH LARVA \ 3, FIGURE-OF-EIGHT

MOTH, WITH LARVA.

September upon the oak and birch, and the pupa is enclosed in a cocoon of bark
chips, or fragments of decayed wood. This insect is very rare in England, but
common on the Continent. In the same group, the caterpillar of the white-
spotted pinion (Cosmia diffinis), as well as that of the closely-allied C. trapezina,
are remarkable for their habit of preying upon their fellow-caterpillars if confined
together, otherwise their food consists of the leaves of various trees. The moth of
the species figured in the illustration is very beautiful, being of a satiny chestnut,
suffused with reddish grey, and having two somewhat transverse slashes from the
margin of the wing. Not uncommon in England, it is even more abundant on the
Continent. The crimson under- wings (Catocala), which indicate another subfamily
(Guadriflnce), and are known in the New Forest as the crimsons, are rich
chocolate-brown of various hues, with deep crimson under- wings, marked with a
pair of transverse black bands. They come to sugar freely in July, and are
common in some parts of England. The finest and rarest of these beautiful
insects is the Clif den nonpareil (Catocala fraxini), very rare in England, but more

LEPIDOPTERA.

ll3

abundant on the Continent. Scarcely less striking is the red under-wing (0.
nupta), in which the grey wings are mottled with darker shades, rendering it difficult
to detect when resting on the grey bark of some forest-tree. The hind- wings are
pale crimson, with a central curving transverse black bar, and another broad black
band along the margin. The caterpillar is grey, with darker brown markings,

1, WHITE-SPOTTED PINION MOTH, WITH LARVA ; 2, PINE MOTH, WITH LARVA. (Nat. size.)

bearing a pale yellow prominence on the ninth segment. It feeds on a species of
willow, Salix fragilis, and the adult appears on the wing in August and September ;
being not uncommon in England, but found more abundantly on the Continent.
In the angle-shades (Brotolomia meticulosa), which is one of the most beautiful, as
it is one of the commonest of British moths, the larva is delicate green, smooth,

RED UNDER-WING, WITH LARVA (iiat. size).

and velvety, thickly speckled with minute white spots. It feeds on groundsel.
The perfect insect, which appears on the wing in May and June, and a second
brood in September, is common throughout Europe. In the prettily -marked
species known as the feathered gothic {Neuronia popularis) the fore-wings are
dark brown, with white nervures. The orbicular and vermiform spots are of the

VOL. VI. — 8

H4

INSECTS.

same colour. The antennae are pectinate in the males, and simple in the female ;
while the hind-wings are dull white, with darker margin. The larva is brown,
streaked and spotted with black and rosy brown, with a pale stripe along the
sides, and four others, more interrupted, along the back. It feeds on the various
kinds of grasses in April and May, while the perfect insect appears on the wing in
the early part of September. Figures of this European species are given below.
The next form for notice is the so-called antler-moth (Charccas graminis), which

2

1, THE FEATHERED GOTHIC, WITH LARVA ; 2, ANGLE-SHADES J 3, THE ANTLER MOTH.

is probably one of the most destructive species in Britain, when, under the
influence of a favourable season, the larvae appear in very great numbers. The
larvae feed upon the roots of grasses, and it is no uncommon thing for whole
districts of pasture-land to become brown and withered, owing to their attacks.
The perfect insect appears on the wing in August and September. A figure
of this moth is given above.

The Loopers, — Family GeometriDsE.

The moths belonging to this group resemble in many respects the butterflies,
having large, ample wings, a small head, and a narrow elongate body. The antennae
are not, however, clubbed ; those of many of the males being pectinated. The palpi
protrude only slightly, the proboscis is present in different degrees of development,
while the head bears no ocelli on the top. When at rest, the majority of these
moths carry their delicate wings slightly expanded, or closed over their bodies,
like the roof of a house, sloping from the centre on either side. They are semi-
nocturnal in their habits, appearing at dusk, and lying concealed during the day
in bushes, trees, and herbage, whence they may be easily driven by beating the
foliage. The larvae differ very decidedly from those of the other families, several
pairs of the pro-legs being wanting, so that locomotion is possible only by alternately
advancing the front and hinder segments, the central portion of the body being
thus raised in the form of a loop. The pupae are sometimes, as in the butterflies,
encircled with a silken thread, but the majority spin together a few leaves,
and change within the receptacle thus formed, or burrow into the earth amongst
dead leaves and moss. Of the first subfamily {Boarmiince) we select as a
representative the handsome pepper-moth (Biston betularia), which is one of the
largest of the European geometers, and resembles members of the family Bombycidce
in the possession of a stout abdomen. The form of the larva, however, is

LEPIDOPTERA.

"5

quite distinct, and closely resembles that of a dead twig. Doubtless such a likeness
saves it somewhat from the attacks of birds and ichneumon-wasps. When fully
extended, and clinging only by its
hindmost claspers, the caterpillar
assimilates so marvellously with the
brown and olive tints of the boughs
among which it takes up its station,
that it is almost indistinguishable
from its surroundings. Another
handsome member of the same group
is the mottled umber (Hibernia
defoliaria), which appears very late
in the season, long after the majority
of the members of the order have
completed the term of their exist-
ence. By night the male circles
around the trunks of trees in search
of his wingless partner. In the
former sex the large wings are pale
ochre in colour, with a darker wavy
transverse bar. The female, on the
other hand, is variegated black and
ochreous yellow, and bears no small
resemblance to some species of spider.
The larvse feed on the buds of various
trees, and descend into the earth to
change into the pupa ; the latter
being dark mahogany, with a sharp
spine at the tail. The species is
not rare in England and on the
Continent. The scarce umber (IT.
aurantiaria), which is figured in the
same illustration, is less common than the last, but appears at the same season.
Nearly allied is the winter-moth (Cheimatobia brumata), which in mode of life is
somewhat similar to the mottled umber, but, as indicated by its scientific name,
flies still later in the year. The larva lives partially secluded amongst the leaves
which it draws together with silk. When occurring in great numbers, these cater-
pillars do serious damage to forest-trees and orchards. The male is of a dusky
grey colour, wTith three darker bands across the upper- wings ; while the female is
wingless. In order to prevent the females from ascending the trees and laying their
eggs on the foliage, it is the custom in Sweden to ring the trunk with a narrow
band of some sticky substance. The bordered white (Bupalus piniarius) is another
well-known member of the group. In this species the males are very abundant,
flying amongst fir-plantations in England and on the Continent. The females are
no less common, but do not take wing so readily. The larva is pale green, with
whitish stripes, and pale yellow spiracles, and feeds during the months of August

PEPPER MOTH, WITH LARVA AND PUPA (nat. size).

n6

INSECTS.

and September on the spines of the Scotch fir. One of the most familiar of the
British loopers is the magpie-moth {Abraxas grossulariata), which at times makes

° GROUP OF LOOPERS.

mottled umber— 1, Male ; 2, Female ; 3, Larva, scarce umber— 4, Male ; 5, Female, winter moth— 6, Male ;

7, Female; 8, Larva. (Nat. size.)

its appearance in great numbers. The perfect insect is prettily mottled with white
and black, and on this account is called in Germany the harlequin-moth. Another
species, the scarce or clouded magpie (A. ulmata), is more abundant in the Midland

bordered white— 1, Male ; 2, Female, with larva ; 3, argent and sable, with larva. (Nat. size.)

counties of England than the common magpie, though less so in the south. Of the
common species the larva feeds on the gooseberry and black-currant, doing consider-
able damage at times. It is one of the most strikingly marked of the geometric

LEPIDOPTERA.

117

larvae, and turns to a yellow-banded pupa within a slightly woven web. The

little moth shown in the annexed illustration, and commonly known as the dark

spinach (Larentia chenopodiata), may

be taken to represent the subfamily

Larentiince. Appearing in July and

August, it is a common species on the

Continent, and is specially abundant

in gardens and shrubberies, where it

may be found resting either on the

bark of trees or the walls of buildings.

The caterpillar is greyish brown in

colour, and feeds on the goose-foot.

The group to which this species belongs

are often termed carpet-moths. Of

another genus, known as pugs (Eupi-

thecia), the lime -speck moth {Ea.

signata) may be mentioned. The

MAGPIE MOTH IN ALL STAGES OP DEVELOPMENT.

DARK SPINACH MOTH AND LARVA (nat. size).

(Melanippe hasiata) appears in May,
flying actively round trees. The
larva may be found later in the year
amongst the birch foliage, in a recep-
tacle formed of several leaves drawn
together with silken threads. The
pupal-state is passed in the ground.
Figures of this moth and its larva
are given on p. 116. The purple-
barred yellow (Lythria pvirpuraria),
figured in the annexed illustration, is
a not uncommon species on commons,
pasture -lands, and stubble-fields in
England and the Continent. The
ground-colour of the wings is pale
olive-yellow, the upper pair banded

ground - colour of the wings is milk - white,
with grey blotches and specks, and a broad
red grey band on the margin. These moths
fly commonly at night in England and on
the Continent, while the larva, which is very
variable in colour — bluish green, yellow-green,
or pinkish white — feeds in August and Sep-
tember on various annuals, such as golden-
rod, rag-wort, etc. Figures of the moth and
larva are given in the illustration below. By
no means a common species in England,
although found occasionally in districts where
birch - trees abound, the argent - and - sable
l 2

1, PURPLE-BARRED YELLOW ; 2, LIME-SPECK.

(Nat. size.)

n8

INSECTS.

with two or three pale vinous-purple bars. The larva, which is brownish yellow
with a pale longitudinal dorsal stripe, feeds on sorrel and docks.

Snout-Moths, — Family Hypenid^e.

The snout-moths {Hypena) are intermediate between the Geometridce and
Pyrcdidce, bearing characters which ally them to both families and yet exclude
them from either. The common snout (H. proboscidalis) is a pale brownish
yellow moth, transversely marked with rusty brown ; and is abundant throughout
England and the Continent from June to September. H. obsitalis has only once
been taken in England.

Suborder Microlepidoptera.

The whole of the remaining members of the order are of minute size, and
are hence generally indicated by the above name, although it must be understood
that many of them are closely allied to some of the foregoing. They are divided
into a large number of families — with their subfamilies and genera — of which only
a very few can be even mentioned here. Among these the pearls (Pyralidce) are
represented by the mother-of-pearl moth (Botys margaritalis), which in June or

July may be seen in Britain hovering
over the fields in the dusk of the
evening, where the female lays her
■^ eggs on the seed pods of the flax
and other plants. When the cater-

MOTHER-OF-PEARL MOTH, WITH LARVA (nat. size).

pillar emerges it spins a few threads
between the pods, and bores through
their outer shell in order to feed upon
the seeds. The moth itself is of a
dull sulphur-yellow, with two trans-
verse rusty yellow bands, intersected
by a rusty brown stripe running obliquely from the tip of the wing. It is common
in June and July on the Continent. To the same family belongs the meal -moth
(Asopia farinalis), found in abundance in summer wherever corn, meal, or grains
are stored in quantities. It rests on the rafters and walls in the daytime, flying at
nightfall. The larva feeds on corn, meal, grain bran, etc., and passes its life in
concealment in a silken tube, of which the outer side is encrusted with particles of
the food-stuffs on which the larva feeds. The larval-state lasts for nearly two
years. A figure of this species is given on p. 120.

The wax-moth (Galleria mellonella) may be taken to illustrate another family
— the Tortricidce. This remarkable moth is double-brooded, appearing on the
wing in the springtime, and again in July and onwards. The larva feeds in
the hives of honey-bees, and, according to some, in the nests of wild-bees as
well. The wax, however — not the honey — forms its food-stuff', and through
the combs it eats long tunnels which it lines with silk as it goes. It does not
seem particularly choice in the matter of diet, and has been successfully reared on
heather, woollen-stuffs, dry leaves, paper, etc. In the case of the wax-eaters, the

LEPIDOPTERA.

119

second brood nourishes itself upon the excrement of the first brood, which seems
to differ in no way from the original wax itself. The moth appears on the wing
in May. An illustration of this insect, together with the larva, pupae, and the
waxen honeycomb on which it feeds, may be seen on p. 121. Another member
of the same family is the oak-tortrix (Tortrix viridana), figured in the annexed
illustration. This beautiful little moth,
bright green with shining grey hind-
wings, may be found flying about in June
in swarms in woods where oak - trees
abound. The larvae which feed on the
leaves, and roll themselves carefully within
the folded leaves, are sometimes so numer-
ous as to become a perfect pest. Acres
and acres of oak-plantation may be seen
completely stripped of the foliage, while
the green moths flutter about in countless
thousands. The pupal-state is passed in
a folded leaf or in the chinks of the bark

or other suitable crevice. The larch-tortrix (Retina buolinana) is a bright, foxy
red moth with habits very similar to those of the last-named species. The moth
may be seen in July flying amongst the trees in young plantations, and laying

OAK-TORTRIX IN VARIOUS STAGES OP DEVELOPMENT

(nat. size).

1, oak-gall tortrix ; 2, Pupa appearing from the resin-gall ; 3, Glypta resinance, ichneumon ; 4, the larch
tortrix ; 4 a, Pupa ; 5, Larva in a larch-bud ; 6, Pupa appearing from gall. (1 and 4a much enlarged.)

its eggs amongst the buds at the tip of the shoots. The larvae are hatched in the
autumn, and commence to gnaw the buds, giving rise to the exudation of resin.
A figure of this moth, with its larva and pupa, will be found in the illustration

INSECTS.

rEA-MOTH AND LARVA.

on p. 119. In the allied pine-gall tortrix (R. resinella) the adult has dark
fore -wings, streaked and mottled with transverse silvery bars and blotches.
The larva feeds within the stem of the buds of the pine-needles, their ravages
causing a drop of resin to exude from the twig which grows larger as the
activities of the internal burro wer increase. If the drop of resin be examined
a small passage at the base will be found passing into the pith of the pine-
twig, and here the larva may be found. This lump of sticky gum, which attains
the size of a filbert, and in which the larva passes the pupal -state, has been
misnamed a gall ; but a gall is not an exuding juice or gum — it is a distinct
outgrowth of the cellular structure of the plant. The woodcut on p. 119
gives illustrations of the moth, the resin -drop, and the pupa. A figure is also
given of the ichneumon-fly, which seeks the larva with its long needle-like
ovipositor ; and from its eggs emerge the grubs which will in due course devour

their nest. An especial interest attaches
to the pea-moth {Grapholitha dorsana),
whose larva is the so - called maggot
which attacks green peas. When full
fed it seeks the earth, and constructs a
cell in which to pass the pupal -stage.
These larvae also are not averse to a pro-
vender of dry peas, to which it often causes considerable destruction. The moth
appears on the wing in May. The well-known codlin-moth (G. pomonella) takes
its name from the circumstance that the larva feeds within apple-trees, eating,
however, not so much the flesh as boring 2 3

into the heart and feasting upon the pips.
It is rosy red, paler beneath, with grey
tubercles, each bearing a long bristle.
This moth flies in June and conceals
itself in the daytime in a crevice in the
bark, with whose tints its grey mottled
wings readily assimilate. The family of
the clothes -moths (Tineidce) is typically
represented by the lesser clothes - moth
{Tinea pellionella), although it must be
borne in mind that there is not one
particular moth which destroys clothing,
but that the larvae of several species are
equally destructive. T. pellionella is one

of the smaller of these, whose larvae, of a silky yellow colour, attack all kinds
of clothing, as well as the upholstery of our furniture. T. tapetzella, a larger
species, attacks more exclusively furs, skin-rugs, etc. A figure of the larvae of one
species will be found on p. 121. In the allied corn-moth {T. granella) the cater-
pillar is very destructive to corn in granaries, feeding indiscriminately upon
various kinds of grain. The female lays one or two eggs on a single corn-grain ;
and after the deposition of all the eggs, the bodies of the adults may be found in
numbers in spider-webs in places which they frequent. The presence of the

1, codlin-moth ; 2, Its caterpillar ;
3, meal-moth. (Nat. size.)

LEPIDOPTERA.

121

caterpillar may be known by the " pass " or excrement on the grains. Several
grains may be spun together, the larva feeding within the shelter of the receptacle
thus formed. Figures of both moth and larva are given in the accompanying

3

1, CORN MOTH, WITH LARVA. 2, LARVA OF CLOTHES MOTH. 3, HONEYCOMB, with 4, LARVA OP

wax moth ; 5, Pupa ; 6, wax moth.

illustration. Of certain allied species there are no English names, so that they

must be mentioned by their scientific titles. Among these, Depressaria nervosa,

3 2 7

4 (5 1

1, nest with larvae of Hyponomeuta malinetta, and 2, The moth. 3, Depressaria nervosa (enlarged) ; 4, The

moth (nat. size) ; 5, Larva (enlarged) ; 6, Pupa. 7, common plume-moth {Pterophorus pentadactylus).

figured in the illustration above, appears on the wing from June to September,
and has reddish grey fore-wings mottled and streaked with black dots. The female
lays her eggs upon cumin, and the larvae soon after they emerge spin together

INSECTS.

the flower-heads, feeding on the seeds and blossoms. When about to enter the
pupal state, the larva bores its way into the centre of the food-plant, gnaws out
a suitable chamber, closes the entrance with a little door of silk, and remains
safe from the attacks of insidious insect foes. In the same illustration is figured
Hyponomeuta malinella, a familiar moth during June and July in English apple-
orchards. The satiny white fore-wings, with three longitudinal rows of black dots,
render it a beautiful and conspicuous object as it rests on the apple-tree by day, or
flies to and fro beneath the trees as the evening draws on. The female lays her
eggs in an elongated cluster on an apple-twig, and the presence of the larvae first
becomes apparent owing to the silky gauze net with which the tiny larvae spin the
leaves together, enlarging their domicile as occasion requires. When full fed,
they pupate also in the web, so that numbers of tiny pupae nestle side by side
where the larvae were wont to feed. When alarmed, the caterpillars drop to the
ground suspended by a thread, crawling actively away amongst the grass.

Another family is typified by the genus Coleophora, which embraces about
seventy species of small moths, characterised by their long narrow wings, margined

with long delicate fringes, the first joint of the
antennae often bearing a tuft of hair. The larvae
live in little cases, in which they pass the winter,
turning to the pupa in the spring. As an example
of the genus, we figure the larch-mining moth (C.
larcinella), which is a dull-coloured moth, whose
larvae eat their way into the needles at the tip of
young larch-trees, the needles attacked, and indeed
often the whole bunch, turning yellow and wither-
ing. The caterpillar is full fed towards the end
of May, when it spins its little case fast to a
larch-needle, and turns to a pupa within. A few
weeks later the moth emerges at the hinder end
of the case. Finally, we have the beautiful plume-
moths (Pterophoridce), of which the common
species (Pterophorus pentadactyhts) is figured
in the illustration on p. 121. Throughout the
family the larvae are hairy, and when full fed
suspend themselves by their anal claspers, turning to pupae without any covering.
The pupae themselves are often hairy also, though many of them are quite smooth.
The plume-moths, as a family, may be recognised by their feathery wings, slender
bodies, and long spinous legs.

F. 0. PICKAKD-CAMBRIDGE.

LARCH MINING-MOTH.

CHAPTER IV.

Jointed Animals, — continued.

Insects, — continued.

The Beetles, — Order Coleoptera.

The beetles are in general easily distinguished from all other insects, and though
they seem almost endless in their variety, and comprise an immense number of
distinct specific forms, constitute a very well defined order. The chief characters
that serve to distinguish them are briefly as follows. They undergo a complete
metamorphosis. Their mouth — which is fitted for taking in solid food — is furnished
with biting jaws (mandibles), a pair of maxillae with palpi, and an undivided, or
very slightly divided lower lip (labium), which also bears palpi. The antennae are
extremely variable in form, but seldom possess more than eleven joints. The
prothorax is usually large and is freely articulated with the following segment
(mesothorax), over which it fits behind in such a manner as almost to completely
cover it on the upper side. The fore-wings are converted into a pair of stiff horny
structures called elytra, which, in a state of rest, usually meet by their edges in a
straight line along the middle of the back, and serve to protect the hind-wings and
the soft hind-parts of the body. The hind-wings are in beetles the only true
organs of flight ; these are membranous and transparent, provided with few
nervures, and when not in active use are generally folded transversely beneath
the elytra. Many beetles are without hind- wings and are said to be apterous ; but
it is to be remembered that very few beetles, except in the larval state, are com-
pletely apterous in the sense of being without both hind- wings and elytra. In the
wingless species the elytra are generally well developed, and frequently fastened
together along the suture where they meet. The presence of elytra, though not
exclusively peculiar to beetles, is still one of their most characteristic features, and
affords in most cases a ready means of recognising them. Elytra very similar to
those of some Coleoptera are, however, met with among the ear- wigs ; and the
elytra of beetles do not invariably meet in a straight suture. Thus in the oil-
beetles (Meloe) one elytron folds partly over the other; while in certain other
groups, the Rhipiphoridce for example, the elytra are of such a form that they
either do not meet at all, or only just touch at the base, and are sometimes so small
and so little like the ordinary elytra of beetles that their true nature is not at first
sight very apparent.

"We have alluded above to the great variety that is to be met with among
beetles. No insects exhibit greater extremes of size ; and we find on the one
hand beetles so small that a pin's head is large in comparison, while on the other

124

INSECTS.

we get those giants of their race, the elephant and goliath beetles, which are
nearly as big as a man's fist, and the still larger titan from South America,
which is sometimes quite half a foot long, and scarcely less broad in proportion.
Even within the limits of a single species beetles are not always of a nearly
uniform size ; and it is not uncommon to find that in certain species some
individuals may be very much larger than others, frequently two or three times
as large, and occasional^ even as much as five times. In their external form
beetles also afford the most striking contrasts ; and the differences of form are not
confined to the general shape but extend to nearly all parts of the body. The
head especially varies to a great extent both in its shape and in the direction
which it takes. It is somewhat ring-like behind, where it fits more or less deeply
into the cavity of the prothorax. The part between the eyes and the prothorax
may be as wide as or even wider than the rest of the head, or may be abruptly or
l 2 s

CARNIVOROUS BEETLES AND THEIR PREY.

1, Carabus nemoralis ; 2, Calosoma sycophanta ; 3, Carabus auratus, and larva. (All nat. size.)

gradually narrowed behind to form a sort of neck. In most beetles this part of
the head is rather short, but its length varies ; and there is one remarkable species
from the Philippines which presents a most comical appearance owing to the
extraordinary length of its neck. This species belongs to a group of leaf-rolling
beetles, and doubtless finds its long neck extremely useful. The fore-part of the
head is most variable in shape, and though generally short is in some beetles quite
out of all proportion in its length. In the weevils it is prolonged in the form of a
rostrum or snout, which is sometimes much longer than all the rest of the body.
What is called the " front " of the head frequently faces upwards, being on the
same plane, or nearly so with the occiput or posterior part of the upper surface.
But in many beetles the fore-part of the head is bent down, so that the front looks
forwards ; and sometimes even to such an extent that the mouth is drawn back
against the prothorax, and the front of the head looks downwards. The lower or
anterior part of the front of the head is called the clypeus, and to this — usually by

COLEOPTERA.

125

the intervention of a short flexible piece known as the epistome — the upper lip
(labrum) is attached. Running along the middle of the under side of the head
there is a piece, generally marked off by a line on each side, which in its posterior
part is named the gula, and in front the submentum. The submentum — sometimes
prolonged beyond the margin of the head in the form of a peduncle — gives attach-
ment to the lower lip (labium), which consists of a basal piece of variable size and
form called the mentum, and a terminal part, the ligula. The latter usually bears
two lobes (the paraglossee) at its extremity, while from its base, known as the
hypoglottis, the labial palpi arise. Between the labrum and labium lie the
mandibles and maxillse. The mandibles are strong biting jaws, and are attached
to the sides of the head by pivot-like joints, which permit only of lateral move-
ments. They are often much larger in the males than in the females, and in the
males of some forms such as the stag-beetles, attain monstrous proportions. Each
of the maxillse consists typically of a stem, composed of two pieces — cardo and stipes
— with a four-jointed palp attached to the outer and two lobes to the inner side of
the free end of the stipes. Except in the larval state, beetles rarely possess those
eyes with a single lens which are known as ocelli. The compound eyes, on the
other hand, are generally large and well-developed, but vary considerably in form,
and in the size and number of their facets. The}^ are often simple in outline,
sometimes slightly notched in front and reniform, or the notch may extend more
deeply and divide the eye into two distinct lobes. Each eye may even be
completely divided into two parts, more or less widely separated from one another ;
so that some beetles appear to have four eyes instead of two. This appearance is
very strongly marked in certain water-beetles, in which one part of each eye is on
the upper, and the other on the under side of the head. The eyes of some beetles
look coarse and granular, while in others they appear quite smooth and glassy-
looking, owing to the small size and slight convexity of their facets. Among the
longicorn beetles, it is generally found that in the nocturnal species the eyes are
coarser and more granular than in those species which fly during the day ; so that
the size of the facets seems to have some relation with the conditions of light
depending on the habits of the insects. But this curious fact does not, so far as we
know, apply to any other family of beetles. Exceptionally also it is found among
beetles that the facets in the upper part of the eye are different in size to those on
the lower part. The antennas of beetles are scarcely less important in their
functions than the eyes. They are in most cases sensitive to touch, and there is
reason to believe that these organs are also the chief seat of the senses of smell
and hearing. They appear under a variety of different forms, some of which,
while subject to minor modification, are pretty constant throughout certain large
groups of beetles, and thus account for the names, Clavicornia, Lamellicornia, etc.,
given these groups. As a rule the antennas, no matter what their length, are made
up of eleven joints or segments ; but this number may be increased, in some cases
to thirty or forty (Rhipicera), and even to as many as fifty (in the Longicorn genus
Polyarthron), or it may be reduced even to so low a number as two (in Platy-
rhopalus). When the joints are more or less cylindrical in form, the antennas may
be either filiform, if of nearly uniform thickness throughout, setaceous if they taper
towards the extremity, or moniliform if each of the joints is short and bead-like.

126 INSECTS.

The antennae are said to be clavate when thickened at the extremity, in the form
of a knob or club ; lamellate when three or more of the terminal joints spread out
in broad processes which lie flat upon one another ; serrate, when the joints have
on one side short angular processes like the teeth of a saw ; pectinate or comb-like,
when the processes are fairly long and stand out nearly at right angles ; or
flabellate, if the processes are proportionately very long. These are some of the
chief types of antennas met with in the Coleoptera ; others of less frequent occur-
rence will be mentioned when we come to treat of the different families. The sense
of smell is undoubtedly very acute in a great many beetles, as anyone acquainted
with their habits could easily testify ; and it is considered probable that certain
minute pits scattered over the surface of the antennas, or crowded together on
special areas, are in some way connected with this sense. Though it is not so easy
to prove that beetles can hear, it seems hardly open to doubt that in some cases at
least they possess this faculty. Every one has heard of the death-watch beetle
(Anobium), which lives in old furniture and wood-work of houses, and makes a
noise like the ticking of a watch. This little beetle produces the noise by hammering
against the wood with its head, and apparently does so for the purpose of attracting
its mate, who replies by making a similar tapping sound. It is easy by imitating
their sounds to get the beetles to answer back ; so that here at least there is some
evidence that these insects are endowed with the faculty of hearing. Many other
beetles are able to make sounds, which though not nearly so intense as the chirping
of the crickets and grasshoppers, and not usually confined to one sex, are produced
somewhat after the same manner by the friction of one part of the body over
another. In beetles the sound sometimes arises from the rubbing of the hind-legs
against the edge of the elytra, but in most cases it results from the rubbing of an
edge over an adjacent area which is crossed like a file by a number of fine parallel
ridges. This stridulating area is in some beetles placed on the upper side of the
back part of the head, or on the gular surface underneath, so that when the head
moves in its socket the upper or lower edge of the prothorax, as the case may be,
scrapes along the file and thus gives rise to the sound. The prothorax of beetles
is, as we have already stated, freely articulated with the mesothorax. Its dorsal
arch or pronotum ordinarily covers over the whole of the mesonotum, with the
exception of the small piece known as the scutellum ; but when the prothorax is
bent down, a considerable part of the mesonotum in front of the scutellum comes
into view. It is on this part that the stridulating area of most of the longicorns
and of some phytophagous beetles (Megalopince) is situated. These insects make a
sort of squeaking noise — which is sometimes fairly loud — by rapidly bending the
prothorax up and down, and so causing its hind edge to move backwards and
forwards over the ribbed surface of the mesonotum. In other beetles the stridu-
lating area may be either on the upper surface of one of the hinder segments of
the abdomen, or on the sides of one of the anterior segments ; the sound being
produced in the one case by the friction of the area against the edge of the elytra,
in the other by that of the posterior thighs against the sides of the abdomen.

Beetles are among the most active of insects when on the ground, and, in accord-
ance with their running powers, we find that their legs, though generally slender, are
strong and well developed. But in certain groups, where the habits and environ-

COLEOPTERA. 127

ment of the insects require it, the legs are adapted to various other purposes.
Beetles that jump usually owe their leaping powers to the greatly thickened
femora and straight and relatively long tibiae of the hind-legs. It would, however,
be a mistake to suppose that when a beetle has thickened and strongly developed
hind-legs it must consequently be able to jump. Some burrowing species, and
others that are not very active in their movements, have very thick hind-legs ;
though, as a rule, it is the front pair of legs which is thickened and otherwise
modified to serve as digging organs in those beetles that burrow underground. In
aquatic beetles the swimming legs are disposed like oars, and have all their parts
broad and flat, while their breadth is further increased by rows of bristles. Either
the hind-legs only, which is the rule, or the middle pair also, as in the whirligig
beetles (Gyrinidw), may be thus transformed into swimming organs. The coxae, or
basal joints of the legs, vary much in shape and in the mode in which they are
inserted in their sockets on the under side of the thorax. Those of each pair are
sometimes close together, sometimes widely separated from another; while a
longer or shorter distance may intervene between the coxae of the different pairs of
legs, and especially between those of the two hinder pairs. Considerable import-
ance attaches to the number of joints in the tarsi or feet. In classifying beetles
this number is one of the first things to be noticed. If a beetle has five joints in
each of its tarsi, it is placed in that section of the order which is known as the
Pentamera ; if it appears to have only four joints in each foot, it belongs to the
Tetramera ; and if but three, to the Trimera. When there are five joints in each
of the four anterior feet, and only four in the hind-feet, the beetle may be regarded
as one of the Heteromera. To these general rules there are a few exceptions which
need not be discussed here ; but we must point out that although in the Tetramera
the tarsi appear to be four-jointed, and in the Trimera three-jointed, they are really
composed of five joints and four respectively. The fourth joint in the one case,
and the third in the other, are, however, usually so small as not to be noticed
except upon very close examination. The abdomen is never stalked in beetles, but
attached to the thorax by a broad base, which is applied against the posterior
coxae; exceptionally, however, as in certain mimicking species, its base may be
more or less narrowed. It is generally somewhat flattened in shape ; and on the
upper side eight segments are usually distinguishable, which, so far as protected by
the elytra, have a soft and but slightly horny integument. Five or six segments
are generally visible on the ventral side, but in certain cases the number may be
reduced. The terminal segments are usually retracted within the abdomen, and
completely hidden from view, but in the females of many species they can be
exserted in the form of a tubular ovipositor, which enables the insect to lay its
eggs deep in the crevices of bark.

Although beetles do not always exhibit differences in external form by which
the sexes may be distinguished, such differences frequently exist, and are some-
times of the most pronounced character. As a rule, the male is more slenderly
built than the female, and has longer and more fully developed antennae ; his eyes
also are often larger, and in the length and shape of the legs, and in the width
and structure of the tarsi, differences in the two sexes are frequently to be noticed.
When the male is fully equipped for flying, the female may be without wings, or

INSECTS.

Zabrus gibbus aiid its larva
(nat. size).

even, as in the case of the glow-worm, without elytra; and whenever there is any
decided difference in coloration, it is almost invariably the male which displays
the brightest and most conspicuous colours. The great projecting horns and pro-
cesses on the head or prothorax which give so grotesque an appearance to many
beetles, are generally wanting or only feebly developed in, the females ; and
these and other differences are sometimes so strongly marked that it is difficult
to recognise in the two sexes individuals of one and the same species.

The larvae of beetles do not in outward appearance exhibit anything approach-
ing the great diversity seen in the perfect insects. They seldom display conspicuous
markings, and are mostly of dingy white, brownish, or black colours. The external

structure and form vary sufficiently to make it possible
to tell to what family of beetles, or division of a family,
a larva belongs ; but, so far as species are concerned,
our knowledge of the larvae is extremely limited, and
applies to a relatively very small proportion of the
whole number of known species of Coleoptera. In
the weevils, and some other beetles, the larvae are soft
white grubs with scarcely any trace of legs, but in most
of the other larvae the legs are fairly well developed,
though not so completely as in the perfect insects.
The head is always horny, and furnished with jaws
for biting and grinding solid food. Exceptionally,
as in the carnivorous larvae of some water-beetles, the mandibles are adapted
for sucking up the juices of the animals on which these larvae prey. The
antennae are short and few-jointed, and in some cases quite inconspicuous. Eyes,
when present, are always in the form of ocelli, which are grouped together in
varying number on each side of the head. The head is followed by a series of
rings or segments, of which the first three — scarcely different in form from the rest
— constitute the thorax, and give attachment to the legs. A pair of prolegs is
sometimes present on the last segment, but in beetle-larvae the intermediate seg-
ments never carry those false legs, which are so often found in the caterpillars of
Lepidoptera and Hymenoptera. The spiracles — which are mostly hidden by the
elytra in the perfect insects — are generally quite conspicuous in the larvae, and
appear as a row on each side of the body. Their number varies ; and in those
aquatic larvae which breathe by means of tracheal gills they are altogether want-
ing. When about to pupate some larvae construct cocoons of earth, or, in the case
of wood-boring species, they may make a shell out of fine chips and dust glued
together with a sticky secretion. The pupae, whether enclosed in a cocoon or not,
are inactive, and show all their appendages lying freely against the body, with
each appendage wrapped round by its own special covering of integument. The
larval existence of beetles varies from five or six weeks in some groups to almost
as many years in others ; and when conditions arise to interfere with the proper
nourishment of the larvae, the period may be unduly prolonged. Some of the
wood-boring larvae seem to live an exceptionally long time. There is at the present
time in the Natural History Museum in London a block of wood containing a
living longicorn larva, which for the past five or six years has been feeding and

E.ETLES IN A FLOOD.

COLEOPTERA. 129

burrowing in the wood. The larva was brought to the museum in a boot-tree,
which its owner previously had in constant use for over fourteen years. Other
cases are on record in which beetles have been seen to emerge from furniture in
houses, after having apparently passed an even more prolonged larval existence.

Beetles, whether from the extent of their numbers or the variety of their
shapes and instincts, are well qualified to play an important part in the economy
of nature. Their chief function is that of universal scavengers. Not only do they
dispose of the smaller quantities of dead and decaying animal and vegetable matter
passed over by larger animals, but, by their own peculiar methods, they are enabled
to attack and clear away even the carcases of quadrupeds of large size, and the
dead trunks of the largest trees. Owing to the compactness of their shape, and
the solidity of their outer covering, they are adapted for a much greater diversity
in modes of life than is possible for insects of other orders. Besides groups fitted
to act as scavengers, we find further series of forms that live in, and prey up^n,
all kinds of plant life. There are groups again, either of terrestrial, arboreal, or
aquatic habits, which seek for, and prey upon living animals of the smaller kinds.
Some beetles live within the depths of the darkest caverns; and in such cases,
having no use for eyes, they are generally blind. Others are to be found dwelling
as " guests " in the homes of the ants and termites. Although the beetles cannot
boast of such a long line of ancestry as the cockroaches and other Orthoptera, yet
their records go back to an early period in geological history. There is no certain
evidence that they existed in Palaeozoic times, and their first appearance has not
been traced farther back than the beginning of the Secondary epoch. The earliest
undoubted fossil remains of Coleoptera occur in the Swiss Trias, and from this
period onwards fossil beetles are to be met with in greater or less abundance in
rocks of different ages. They are especially well preserved in amber ; and from
the Tertiary amber beds on the Baltic thousands of specimens have been collected.

Of the beetles now existing, quite one hundred and thirty thousand different
species have been described, and, considering the rate at which new species
are being yearly added, it is probable that before the end of the century the
number of named species will fall little short of one hundred and fifty thousand.

SECTION PENTAMERA.

Beetles in which all the tarsi are five-jointed. In this section there comes first
a great tribe of beetles, which, on account of their carnivorous tastes and predaceous
habits, are known as the Adephaga. Their whole organisation seems well adapted
to enable them to capture and devour their prey, and it is in the modifications
directed to this end that some of the chief distinguishing characters of the tribe are
to be found. Their legs are fitted for speedy locomotion, and their jaws for the
cutting and tearing operations to which they are usually applied. The mandibles
are acutely pointed and have sharp cutting edges ; and the inner lobes of the
maxillae are hard and hooked at the end. The outer lobes of the maxillae are two-
jointed and slender, and resemble palpi ; which explains the fact that these beetles
are often described as having three pairs of palpi. The antennae are usually
simple, and never clubbed. The tribe is divided into the Geodephaga and
Hydradephaga, one subtribe containing terrestrial, the other aquatic forms.

VOL. VI. — Q

130

INSECTS.

The Cicindelidce consist of about one thousand known species, which are dis-
tributed throughout the world, but are much more abundant in tropical than in
temperate or cold countries. In Europe two genera only are represented — Tetracha,
which comprises nocturnal and twilight-loving species, and Cicindela, whose species
are found in the hottest and sunniest places. The tiger-beetles are extremely
pretty insects of remarkably active habits, and exhibit the predaceous type of
structure to perfection. Besides possessing great speed of foot, most of them make
ready use of their wings, and they are further characterised by large and prominent
eyes, and mouths well adapted for seizing and holding their prey, the mandibles
being long and provided with a number of sharp teeth, while the inner lobe of the
maxillae is furnished with a movable claw or hook at the tip. The fact that this

hook is movable and not
firmly fixed to the blade
of the maxillae, affords a
means of distinguishing
the tiger-beetles from all
the other beetles of the
tribe Adephaga. More
than half of all the
known species of the
family belong to the
single genus Cicindela,
and this is the only genus
which is cosmopolitan.
With the exception of a
few species of an almost
entirely ivory - white
colour, the Cicindelidce
exhibit greenish, bronzy,
or darker metallic tints, frequently varied with white or pale yellow spots and
bands, which in the case of a great many species run together to form more or less
intricate and pretty patterns. While their shape is usually such as is shown in
our figure of C. hybrida, we get, on the other hand, remarkable exotic forms, in
which the body is narrow and elongated, and broadest towards the hinder end.
Collyris and other genera of the various Oriental countries — where the species are
found pursuing their prey on the trees in the forests — afford examples of this type.
From its great resemblance in colour and form to Collyris, a rare and curious
longicorn beetle, found in the same localities, has been named Collyrodes ; and it
has been remarked by Mr. Wallace that beetles of the family CicindelidcB are
amongst those most frequently mimicked by other beetles.

In external structure the carnivorous ground -beetles (Carabidce) approach
the Cicindelidce, from which they may in most cases be distinguished by their
general shape, as well by the fact that they never exhibit the coloration and
markings characteristic of that family. Other points of difference may be seen
in their less prominent eyes, in the absence of an articulation in the hook of
the maxillae, and in the shape cf the mandibles, which, though occasionally long,

TIGER-BEETLES.

Cicindela hybrida (with larva and pupa slightly enlarged) ; Collyris
longicollis (enlarged).

COLEOPTERA.

131

do not exhibit the slender curved form and sharp dentition met with in the tiger-
beetles.

The number of species of Carabidai at present known can scarcely be less than
eleven thousand. This family seems better represented in temperate and colder
regions than within the tropics, though species, in more or less abundance, are to
be found in every country and island of the world. Whilst the species are almost
all predaceous in their habits, we find them under a variety of different forms and
with several distinct peculiarities of structure, many of which are to be regarded as
special adaptations to the various situations in which the insects hunt for their prey.

The Carabidw like all other beetles have their enemies, but we never find in
this family any of those mimetic and protective disguises that are so commonly
met with in certain other groups ; and to escape from their enemies the ground-
beetles have mostly to rely upon their speed of foot, or the readiness with which
they can take to flight or disappear amongst the herbage. Many species are, how-
ever, provided with anal glands that secrete an acrid or stinking liquid which is
sometimes ejected with considerable force when the insect is handled. In the
" bombardier-beetle " (Brachinus crepitans) and others of the same group, the
secretion is volatilised on emission, and issues as a little cloud of smoke, which is
accompanied at each discharge by a slight sound ; and when the insect is irritated
it repeats the discharge several times in succession, but each time with diminished
force. The " bombardier " is a rusty-red species, with dull blue-black elytra, and a
narrow head and prothorax, and is pretty common, especially on chalk, in different
parts of the south and south-east coasts of England. Amongst those species of
the family that in habits and general appearance most closely resemble the
Cicindelidce, are the little beetles of the genus Elaphrus. These love to run about
in the rays of the sun, not so much in dry places, as on the muddy banks of
rivers, on the sands of the seashore, and in other damp situations. They have
large prominent eyes, a narrow prothorax, slender legs, and curiously marked
elytra. This genus is confined to the Northern Hemisphere. The species which
we figure, Elaphrus riparius, like some other beetles of
the family, is able to produce a stridulating noise by
rubbing the back of its abdomen against a projecting
nervure on the under side of the elytra. Those tiny
little beetles of a glistening bronzy-black appearance,
and with beautifully sculptured elytra, which are to be
seen on almost any bright day in the spring or summer,

running quickly over garden beds or paths, belong to MaphrmHpaHus (enlarged),
the genus Notiophilus, and are some of the smallest

species in the whole family. The genus Carabus, after which the family is
named, contains over three hundred species, and is somewhat remarkable in its
distribution ; for, with the exception of a small group of species found in Southern
Chili, it is restricted in its range to the North Temperate zone. Six or seven
species are found in Britain ; Carabus violaceus and C. nemoralis are perhaps the
two most frequently met with, being abundant in gardens and fields in almost
every part of the country. The first is nearly smooth, of a dull blue-black colour,
with purplish borders to the thorax and elytra, and is of about the same size

132

INSECTS.

as G. nemoralis (represented in the figure on p. 124). The latter has a purplish
thorax and bronzy elytra, marked with a few rows of conspicuous punctures.
Another species which we figure, C. auratus, is very rare in England and doubtfully
indigenous, but in France it is common and does much service by destroying the
cockchafers and their grubs. The genus Galosoma approaches Carabus in many
of its characters, but may be easily distinguished by its shorter, broader, and more
rounded prothorax, and the greater relative width of its elytra. Galosoma
inquisitor, though rare and found only in parts of England, may be regarded as a
true British species ; but the species figured (C. sycophanta) is only an occasional
visitant to this country and cannot be considered indigenous. The Carabidoe. as a
whole, though sufficiently varied in their external structure, do not exhibit any very
unusual or striking peculiarities of form, and the species already considered, with
a few more presently to follow, may be taken as typical of the commoner forms
met with throughout the family. In the genus Mormolyce we have, however, a
remarkable exception. The species of this strange genus — three in number, and all
very much alike — have been found in Java, Sumatra, and other East Indian Islands.
They are of a pitchy-brown colour, and have the body much flattened, and the

head greatly elongated, while their
antennae are also very long ; but, as
will be seen from our figure, the chief
peculiarity in the appearance of these
extraordinary insects is due to the
great lateral expansions of the borders
of the elytra, and the curious manner
in which these expansions are pro-
longed behind. M. phyllodes, the
best known species, occurs in Java,
Borneo, and the Malay peninsula;
and the people of Java, struck no
doubt by its peculiar shape, call it " the violin." Some of the largest individuals
of the species are nearly three and a half inches long, and measure more than
an inch and a half across the broadest part of the elytra. We have
alluded, in our introduction, to the burrowing habits of some of the
Carabido3. The Scaritinai are a group that possess such habits, and
the accompanying figure of Scarites gigas will give an idea of the
general form characteristic of nearly all the species of the group.
The genus Scarites comprises a large number of species, all of a
uniform black colour, and most of them of a moderate size. They
make their burrows in the banks of streams, the seashore, or other
suitable places, and rarely leave them during the day, lying in wait
for their victims at the mouth of the holes. The genus Zahrus,
which we have next to notice, forms, so far as its habits are con-
cerned, one of those exceptions that go to prove the rule. For,
while it is true that almost all the Garabidm are carnivorous and predaceous
insects, some at least of the species of Zabrus and a few others are largely, though
probably not wholly, addicted to a vegetable diet. The species {Zabrus gibbus)

Morniolyce phyllodes (from a small specimen).

Scarites gigas
(nat. size).

COLEOPTERA.

*33

figured on p. 128 lives in corn-fields, and has at different times committed great
havoc among crops — wheat, barley, rye, etc., in various parts of Germany and Italy.
The Dytiscidce or carnivorous water-beetles, resemble the Carabidce in many
of their structural features, and differ chiefly in the modifications undergone to fit
them to an aquatic mode of life. Thus we find, as in the latter family, the
mentum is usually broad and deeply emarginate in front, the outer lobe of the
maxillae is two-jointed and palpiform, the antennae are moderately long and slender,
and the trochanters of the hind -legs are prominent. On the other hand, the
antennae are always smooth ; the head is broad and fits deeply into the prothorax,
while the latter is applied by a broad base against the elytra, so that the outline
of the body is continuous, and the general shape more or less oval ; the hind-legs,

J)ytiscus marginalis

Sf./lSffl,/.^

- 1, Male ; 2, Female ; 3, Eggs ; 4, Pupa ; 5, Larva attacking a tadpole ; 6, Hydrocharis
caraboides ; 7, Its larva; 8, Acilius sulcatus, Female. (All nat. size.)

which with their tibiae and tarsi flattened and furnished with rows of bristles,
are adapted to serve as oars in swimming, are somewhat longer than the other
legs, and come off from the body at a considerable distance behind them, while
their coxae appear as broad flat plates firmly joined to the metasternum, for parts
of which they might at first sight be very readily mistaken. The males may
be distinguished from the females by the shape of their fore-tarsi, in which the
first three joints are strongly dilated, and furnished underneath with sucker-like
hairs ; while in this sex also the back is generally smooth and glossy, the elytra
of the females frequently have a ribbed or corrugated surface. The Dytiscidce
seem especially fond of stagnant waters, and some of the species are common
objects in our ponds and ditches. They come to the surface when it is necessary
to take in a fresh supply of air beneath the elytra. These organs fit very closely
against the sides of the body, and so prevent the air from escaping while the beetle

i34 INSECTS.

is swimming about under the water ; but the air meanwhile is being used up in
breathing by means of the thoracic and abdominal spiracles. The beetles fly
strongly, and on fine summer evenings may sometimes be seen winging their way
to new quarters, a change which is often necessitated by the drying up of the pools
in which they had previously been living. Dytiscus marginalia, one of the largest
British species, is also one of the commonest and best known. Another common
species, Acilius swlcotus, is also represented in our figure.

The Gyrinidai, or whirligig beetles, are a small but very well-defined group, and
in many points of structure are sharply distinguished from the other families of the
tribe Adephaga. In their oval shapes they resemble the Dytiscidw, though they are
usually somewhat flatter below and a little more convex on the upper side. But in
the relative proportions of the three pairs of legs they are
entirely different. The fore -legs are long and slender, and
when stretched out look like arms, whereas the two hinder
pairs are short and broad, being modified for use as paddles in
swimming. Another very distinctive feature is presented by
the eyes, each of which is divided by a ridge on the side of the
head into two widely separated portions, one lying on the upper
commos whirligig gjjy 0f ^he heaci and the other underneath. These beetles

beetlk, Gyrinus . ......

natat&r (enlarged). appear, in consequence, to have four eyes ; one pair, as it is said,
though there is no proof of the fact, for espying objects above
them, the other for looking at things in the water below. From the Dytiscidai
and Carabidce they differ further in having their antennae shorter than the head,
and the outer lobe of the maxillae either completely atrophied or else in the form
of a slender spine. The Gyrinidoi, though widely distributed and represented in
almost all parts of the world, include altogether rather less than three hundred
known species. The genera are few in number and two only occur in Europe.
Some of the British species, such as Gyrinus natator, are commonly to be seen in
ponds and canals or " holes " in reedy sluggish streams, where the shiny little
beetles attract attention by the ease and rapidity of their movements as they skim
about on the surface of the water, performing a variety of intricate evolutions,
some sweeping along in graceful curves, others going round in circles or spiral
tracks, now all collecting together in groups, and then, if startled, suddenly darting
off with amazing speed in every direction.

The next beetles we have to consider are those which, on account of their
abbreviated wing-cases, are known as the Brachyelytra. This tribe to which,
however, not all beetles with short elytra belong, contains a single very large
family — the Stapliylinidai. Owing to the shortness of their elytra, and the usually
narrow and elongated form of their bodies, the rove-beetles have an easily recognised
and characteristic appearance. The head is generally large and flat with a narrow
neck behind where it fits into the prothorax. The antennae — composed of eleven,
or occasionally twelve joints — are usually filiform, but are often slightly thickened
towards the extremity, and in some cases end in a distinct club. Though prominent
and conspicuous in a few genera, the eyes are, as a rule, raised but very little above
the general surface of the head. It is interesting to note that ocelli, which are of
such rare occurrence in adult beetles, are to be found in certain groups of this

COLEOPTERA.

[35

family ; two ocelli being present in Homalium and its allies, and a single ocellus
in the genus Phlceobium. The mandibles vary in form according to the habits of
the species ; they are usually strong, often sharply curved and pointed at the end,
and of a distinctly carnivorous type. Attached to the base and running a little
way alongside the inner margin of each mandible, there is to be seen in many
species a narrow flexible plate fringed, or not, with hairs at the end. This piece,
first made known by Kirby, who called it the prostheca, is rarely met with
except in the Staphylinidw. The ligula is' narrow, and bears distinct para-
glossae ; and the outer lobe of the maxilla is never palpiform. The rove-beetles are
for the most part carnivorous, and prey upon all kinds of larvae and other insects,
as well as upon slugs, snails, and worms, but they feed largely on carrion, and to
some degree on vegetable matter. Several species live in fungi, some in flowers,
others under bark and in rotten wood, while in the case of certain genera, such as

BRITISH ROVE-BEETLES.

1, The devil's coach -horse (Ocypus olens) ; 2, Staphylinus pubescens ; 3, Philonthus ceneus ; 4, Ooiypcrus rufus ;
5, Poederus riparius ; 6, Staphylinus ccesareus. (Nos. 3, 4, and 5, slightly enlarged.)

Lomechusa and Atemeles, the species are to be sought for in or about ants' nests.
Some of these latter species are welcome guests, since, like the Aphides, they
secrete a liquid which is eagerly swallowed by the ants ; others may possibly act as
scavengers. Amongst the species of the genera Spirachtha and Corotoca, which
live with the Termites in South America, some are very remarkable from the fact
that the females give birth to living young.

Many of the British species of beetles belong to this family. Every one has
seen the devil's coach-horse, that long, black, ugly-looking but useful insect which
is to be found under stones and earth, or roving about in gardens, and which when
you attempt to stay its progress, by pointing with a stick or finger, stands with
threatening jaws and upturned tail as if ready to accept the challenge. This species
which, with a few others, is represented in the figure, is scientifically known as
Ocypus olens, and is one of the largest of the rove-beetles. Its habit of turning
up the tip of the abdomen is not peculiar to it, but is common to nearly all the
beetles of the family, which on that account are sometimes called cock-tail beetles.

We come now to a series of small families, forming the group known as the
Clavicornia or Necrophaga. This group, however, rests on no true scientific basis,

136 INSECTS.

and is more or less artificial in its character. Most of the species included in the
group feed upon decaying animal or vegetable matter, hence the name Necrophaga.
The antennae exhibit in general a tendency to be thickened towards the tip, and in
many cases the last three joints form a distinct club ; but in some of the families
antennas of quite another shape are to be found. Though usually five-jointed, the
tarsi display in the number of their joints almost every variation met with in the
Coleoptera.

The family of Paussidce includes probably less than two hundred known
species, the majority of which have been discovered in the tropics of Asia and
Africa, though one species (Paussus favieri) occurs in the south-west of Europe.
They are mostly reddish brown insects, of rather small size, oblong form, and in
general appearance little attractive, were it not for the extraordinary shapes of
their antennae. These organs are generally very broad and flat, in some species
resembling a paper-knife in shape ; the number of joints varies from ten to two,
and the last joint frequently has a bulbous or discoidal form. So far as at present
known, all the species live in ants' nests, and, unless sought for in these situations,
they are rarely seen except at night when they occasionally fly into rooms, attracted
by the light from the lamps.

The tiny beetles belonging to the Pselaphidce resemble the Paussidce in exhibit-
ing certain anomalies in their structure, and their lives are passed in similar obscure
situations. But while the Paussidce may possibly be related to the Carabidce, the
very short elytra of the Pselaphidai, and the entirely horny nature of the dorsal
plates of the abdomen seem to indicate an affinity with the Staphylinidce. In
other points of structure, however, these two families are different. In the
Pselaphidce the lobes of the maxillae are soft and membranous ; and the abdomen,
which in one group (the Clavig evince) is composed of five segments, with the basal
rings fused together, is quite incapable of the movements so characteristic of the
rove-beetles. The joints of the antennae vary in number from eleven to six,
or even two, and are in most cases clubbed at the end. While in one division
of the family the palpi are usually composed of three or four joints, and are
long and conspicuous, in the other they are one-jointed and scarcely visible.
The tarsi are three-jointed, the first and second joints often very short, while
the third is long and in many cases bears only a single claw. The Pselaphidce
are distributed throughout most parts of the world. They are to be found
under stones, moss, dead leaves, and other vegetable refuse, as well as under
the bark of trees, and in damp marshy situations ; but the most interesting
species are those which live in ants' nests. They are all of small size. The genus
Glaviger, comprising about eighteen European and one or two Asiatic species, has
six-jointed antennae, and is further remarkable for the fact that the long cylindrical
head is entirely devoid of eyes. The best known species, C. testaceus, is in
Britain met with chiefly in the nests of the common yellow ant (Lasius flavus),
though on the Continent it is found also in the nests of other species. It is
about a tenth of an inch long, yellowish brown in colour, wingless, with the
elytra fused together, and with a deep impression on the base of the abdomen.
The relation between the ants and their guests is of a most interesting character.
Whenever an ant meets one of these guests in a gallery of the nest, it gently

COLEOPTERA.

137

Claviger testaceus, caressed by ants (greatly enlarged).

touches and caresses it with its antennae, and while the beetle responds in a
similar manner, the ant sucks at the tufts of hair near the end of the beetle's
elytra, and then licks the whole anterior surface of the back of its abdomen.
The ants feed the beetles in very much the same way as they feed their larvae.
When the beetle is hungry it expresses its desire to be fed by licking an ant near
the mouth, and occasion-
ally stroking the sides of
its head with gentle
movements of its
antennae. During the
process of feeding the
beetle is passive ; the ant
moves its head gently to
and fro, while the head
of the beetle rests almost
motionless in its mouth.
The attention bestowed

by the ants on the beetles is as great as that which they give to their own larvae,
and they frequently feed the hungry ones among them, before looking after the
wants of their own brood.

The orange-banded burying-beetles of the genus Necrophorus are probably
the best-known members of the Silphidce, though they are not to be considered the
most representative, either in habits, size, or general appearance. The many genera
of which the family is composed differ greatly in size and outward form, while the
burying instinct is almost entirely confined to the genus Necrophorus. In nearly
all cases, however, the antennae, consisting usually of eleven joints, are thickened
towards the tip or furnished with a distinct club ; the prothorax is usually broad
and flat, with sharply defined lateral margins, while the elytra frequently do not
reach to the tip of the abdomen; the coxae of the four anterior legs are large,
prominent, and conical in shape ; and the tarsi are usually five-jointed, though
occasionally with a less number of joints. The Carrion - beetles are widely
distributed, though chiefly characteristic of the colder and temperate zones.
In the genus Necrophorus the antennae terminate in an almost globular, four-
jointed mass ; the body is broadest across the ends of the elytra, which are
abruptly truncated, leaving the tip of the abdomen exposed. The species of this
genus are black in colour, but in most of them the elytra are crossed by two
broad orange bands. They feed upon dead animals of all kinds, and their habit of
burying the smaller carcases, such as those of mice, moles, small birds, etc., has gained
for them the name of " sexton " or " burying " beetles. Their mode of operation is to
creep underneath and dig the earth away until they have made a hole big enough
to receive the dead body ; as the latter sinks, the loose soil closes over it and in
time completely hides it from view. The females then lay their eggs in the
carcase, which subsequently serves as food for the larvae. These insects must have
a very acute sense of smell, for in a very short time after a mole has been killed
some of them may be seen hovering over the body, although not previously
observed anywhere in the vicinity. Out of about a dozen species of Necrophorus

i3»

INSECTS.

occurring in Europe, seven are found in Britain, N. vespillo being perhaps the
one which is most widely distributed. Most of the species of the genus Silpha —
from which the family name is derived — are dark, sombre-looking insects, some-
what ovate in shape, the prothorax being broad and closely applied to the base of

the elytra, while the elytra
usually extend to the tip of
the abdomen. The head is
small, and when turned down
is hidden under the pronotum.
The beetles themselves are
generally met with in or about
dead animals, but some of the
species display a partiality for
a vegetable diet ; thus in
France the adult Silpha
reticulata has been found to
attack wheat, while Silpha
nigrita devours strawberries
in the Alps and Pyrenees.
The larvae of most of the

Silplut atrata and larva (rather less than nat. size).

species are somewhat like wood-lice in shape, with the posterior angles of the
abdominal segments sharply produced. Those of S. opaca and S. atrata are some-
times very destructive to the leaves of sugar-beet and mangold-wurzel.

The Trichopterygidce, or hairy-winged beetles, are exceedingly minute insects,
the smallest, in fact, of all- the beetles, many of the species being less than the
fiftieth part of an inch in length. They are further remarkable on account of
the structure of their wings. These
organs are very long and narrow,
each consisting of a strip of mem-
brane attached to a horny stalk and
fringed on each side with long and
closely-set hairs.

The HisteridcG form a well-
defined family, widely distributed,
and numbering considerably more
than twelve hundred species. In
colour they offer little variety, being
mostly either black, dark blue, or
green, the elytra being occasionally
spotted with red or yellow. They

are compactly oval or oblong-oval in form, and nearly always present a highly
polished appearance. The antennae are short, with a long basal joint and a very
distinct terminal club, and as a rule are capable of being turned back into grooves
beneath the thorax. The elytra are truncate at the tips, leaving the last two
segments of the abdomen exposed ; they are generally marked with a series of finely
impressed longitudinal lines, the number and disposition of which afford useful

Hister fimetanus and larva (nat. size).

COLEOPTERA.

*39

characters in distinguishing between the different species of a genus. In the
division of the family to which Hister belongs, the prosternum is produced in
front, forming a prominent " chin-piece " which serves to protect the lower part of
the head when the latter is retracted. In Saprinus the " chin-piece " is wanting.

The Nitidididce have some resemblance in external form to the Histeridce,
though they are generally of smaller size, with their integuments less hard, and
their colours a little more varied. The elytra are
slightly truncate behind, leaving a variable number of
the segments of the abdomen exposed. The antenna?
are eleven-jointed or, exceptionally, ten-jointed, with
the last two or three joints forming a knob; the maxillae
have as a rule but a single lobe, and the tarsi are five-
jointed, though in a few genera the males, at least,
have only four joints in the posterior tarsi. Many of
the species are found feeding and breeding in decaying
vegetable or animal substances, such as rotten wood,
bark, fungi, and in carcases or bones ; some frequent
the exuding sap of trees ; while a very large number
are to be seen on flowers, amongst which are the
brightly-coloured little beetles of the genus Meligethes.
The species figured (M. cenews) is one of the commonest,
and met with chiefly on the flowers or leaves of cruci-
ferous plants. In Germany these little beetles are well
known, on account of the depredations they commit
in crops of rape. A few days after emerging from
their winter sleep, the beetles lay their eggs in the
buds ; in about a fortnight the larvae are hatched and
proceed to feed on the undeveloped or full-blown
flowers ; while later on they attack the young pods,
to which they do more damage than the beetles them-
selves. The small family Byturidce may also be
mentioned here. The genus Byturus contains only
four or five known species, which are confined to
Europe and North America, and one of which is
familiar to gardeners and others as the " raspberry
beetle." This species (B. tomentosus) is somewhat
oblong in form, from an eighth to a sixth of an inch

in length, of a dirty yellowish colour, and covered with a yellow down. Though
found on flowers of many different kinds, it is especially common on raspberry
blossoms, and the cylindrical brownish larvae sometimes do much damage to the
flowers and fruit.

The Dermestidce have a special interest, owing to the destructive habits of
many of the species. The beetles themselves are small in size, oblong or oval
in shape, sometimes nearly round, and usually clothed with fine closely lying
hairs or scales, which frequently give rise to greyish or yellowish spots or bands
on the elytra. The front of the head, except in the genus Dermestes, bears a single

Meligethes ceneus (nat. size and
greatly magnified).

i4o INSECTS.

ocellus ; the short antennae, consisting usually of eleven joints, are clubbed at the
end ; the abdomen is entirely covered over above by the elytra ; and the tarsi are
always five-jointed. While certain species are met with only on flowers, the
majority live in dried animal matter — furs, skins, and the like, as well as articles
of food, such as bacon and cheese. The perfect insects do comparatively little
damage, the real depredators being the larvae, including those of many species
which in the adult state frequent flowers. The larvae are little hairy creatures of
a dark colour, looking like small caterpillars, with the hairs sticking out straight
and arranged more or less in tufts or bundles. The larvae of Anthrenus musceorum,
the so-called museum-beetle, have to be carefully guarded against in museums, as
they are very destructive to zoological collections and more especially to those
of dried insects. Attagenus pellio is another very common species of this family,
usually found in houses, and well known on account of the ravages of its larva in
natural history collections, furs, hair-stuffed couches, etc. The larva is of a brown
or red-brown colour above, and covered with long hairs pointing backwards; it
is broader in front and tapers towards the hinder end, where it carries a tail-tuft of
very long hairs.

In the Hydrophilidce the antennae are short and composed of from six to
nine joints, of which the first is relatively long, and the last three or so thickened
in the form of a club ; the mentum is a large shield-like plate without a notch in
front ; the lobes of the maxillae are not toothed, and the palpi are long and slender,
frequently much longer and more conspicuous than the antennae. These characters
afford a ready means of distinguishing these herbivorous water-beetles from the
carnivorous water- beetles, to which in general shape many of them bear a close
resemblance. The great length of the maxillary palpi has given rise to the name
Palpicomes by which the family was formerly known. In the perfect state, all
the members of the family feed upon vegetable matter ; but it is only those of the
subfamily Hydrophilince — of which the great water-beetle, Hydrophilus piceus,
may be taken as the type — that are truly aquatic in their habits ; the second sub-
family, the Splicer idiince, though including certain marsh-frequenting species, is
composed mainly of land-insects which are found chiefly in vegetable refuse or
in the droppings of herbivorous mammals. Of the Hydrophilince some are
found in stagnant, others in running water, but they are nearly all poor swimmers,
while a large number progress by simply crawling along the surface film upside
down ; in their slow movements they present a marked contrast to the active
predatory Dytiscidce.

Having touched upon the principal families of the Clavicorn series, we pass
to the Pectinicornia, a small tribe containing only two families, one of which
has no European representative, while both are somewhat limited in the
number of their species. In the Lucanidce the antennae are ten -jointed, with the
first joint long and set at an angle with the rest of the antennae, of which from
three to seven of the last joints are furnished with rigid tooth-like processes on
one side. The outer lobe of the maxillae ends in a pencil of hairs, while the inner
lobe has very often the form of a claw ; the ligula is membranous or leathery in
texture, and is attached to the inner face of the mentum ; the elytra cover over the
abdomen, which on the ventral side shows five or, in the male, six segments;

COLEOPTERA

141

and the tarsi are five-jointed, with a long slender spur projecting between the
claws of the terminal joint, and carrying at the end two long bristles. The male
insects are remarkable for the massive development of their jaws, which in many
cases are forked and branched. The common stag-beetle (Lucanus cervus), one of
the largest of European beetles, may, in the case of full-sized males, attain a
length of over 2 inches, or, if the mandibles be included, more than 3 inches. It is
most abundant in the neighbourhood of oak-woods, and in England is not
uncommon in the southern counties, where the males may be often observed on
the wing on fine summer evenings, flying with a loud hum.

The Passalidcc are a small family of about two hundred known species, which
are almost entirely restricted to the warmer parts of the world, the greater pro-

"pY/'1-' ^

1, Larva.

GREAT BLACK WATER-BEETLE (nat. size).

2. Male. 3, Female with egg-cocoon.

portion being found in America. In the form of the antennae and in some other
respects they show an affinity with the Lucanidce, though easily distinguished by
the character of the mouth-parts. The ligula is horny, and lies in a deep quad-
rangular emargination in the mentum ; the lobes of the maxillae both resemble
claws; and the mandibles offer a peculiarity of structure met with in no other
family, each being provided with a movably articulated tooth placed close to the
basal molar surface.

The Lamellicornia — comprising the burrowing-beetles, cockchafers, and a host
of other forms, differing both in habits and external structure — are represented in
all parts of the world, though relatively less numerous in Australia than in the
other great regions. We have only to mention the goliath-beetles of West Africa,
and the elephant and hercules-beetles of Tropical America, to indicate the great
size attained by some of the species ; while as regards beauty and brilliancy of

142

INSECTS.

burrowing beetle, Scarabceus variolosus (nat. size).

coloration no beetles can rival many of those belonging to the two subfamilies
Getoniince and Rutelince. The male stag-beetles, as we have just seen, are
distinguished by their large heads and monstrous jaws, but in the males of the
present family it is as a rule the prothorax which is greatly enlarged or

otherwise modified in form, and
often furnished, like the head, with
5s processes of various kinds, some-
times short, in others taking the
shape of huge curved or branching
horns. The family admits of two
principal divisions. In the first
division the ligula of the lower
lip is more or less membranous and
distinct from the mentum, and the
spiracles of the abdomen are all
situated in the connecting membrane
between the dorsal and ventral plates. Among these we may mention the genus
Scarabceus, over sixty species of which are known, most of them African, some
occurring in Asia, and a few, including sacer, one of the
sacred beetles of the Egyptians, found also in South Europe.
Amongst the coprophagous species, met with in Great Britain,
those of the genus Aphodius, which represents a second sub-
family, are the most numerous. They are somewhat oblong
in form, as shown in our figure of Aphodius fossor, one of
the largest and best-known species, and are usually shining
black, though in many the elytra are of a reddish or yellow
colour, in some cases spotted with black. A type of another
subfamily is found in the genus Geotrupes of which we have
in this country several species, including the well-known
" dumble-dor " or " shard-born " beetle (G. stercorarius). The

species almost all exhibit dark blue or black colours, and in most cases the sexes
differ little in external form; but in G. typhosus, the male is
distinguished by having three horns projecting from the pro-
thorax. The plant-feeding or phytophagous subfamilies belong
to the second division of the Scarabceidce. In these the ligula
is consolidated with the mentum, and the abdominal spiracles
are placed, some in the connecting membrane between the dorsal
and ventral plates, the others on the sides of the ventral plates.
One of our most familiar insects, the common cockchafer, gives
a good idea of the general form and style of coloration pre-
vailing in the subfamily Melolonthince, while in habits also it
resembles other species of the same group. As examples of
some of the other Melolonthinw we figure Polyphylla fullo,
one of the finest European species, which, though not indigenous
to Britain, has occasionally been found on the south coast, and — on p. 144 —
Rhizotrogus solstitialis, a common British insect, commonly known as the summer-

Scarabceus sacer (nat. size).

Aphodius fossor, with
larva (enlarged).

COLEOPTERA.

M3

male of Geotrupes
typhosus (nat. size).

chafer. The Rutelince have some resemblance in external form to the Melolon-
thince, but can in general be easily recognised owing to the difference in length
between the two claws of each of their tarsi. The Dynastince are mostly confined
to the warmer parts of the world, and chiefly remarkable on account of the
great sexual differences exhibited by the species. In the
hercules-beetles (Dynastes hercules), of the West Indies and
Tropical America, the male is sometimes over 5 inches long.
The elephant-beetle is a more massive insect, though, having
relatively much shorter horns, its total length is not so great.
As compared with other species of the subfamily the European
rhinoceros-beetle (Oryctes nasicornis), figured on p. 144, is
very modest in its proportions. Our next subfamily, the
Cetcmiince, stands unrivalled amongst the Coleoptera for the
loveliness of coloration displayed by many of its species.
The goliath-beetles belong to this subfamily. In some of the
genera, such as Ceratorrhina and Goliathus, the males may be recognised by
the shape of the head, which is often excavated above, and furnished with hooks
or horns, as shown in C. smithi on p. 145.

The Buprestidce, together with the click-beetles (Elateridce), and a few smaller
families, constitute the tribe Serricornia. Distinguished chiefly by their serrated
or flabellated antennae, the beetles of this tribe agree also in having the tarsi five-
jointed, and the presternum prolonged behind
and fitting into a cavity of the mesosternum.
They are generally of an elongated form, with
the elytra narrowed from the base to the tip
and completely covering the abdomen. The
Buprestidce have short, serrated antennae,
composed of eleven joints, which, with the
exception of three or four nearest the base,
are covered on special areas with very
minute pits supposed to be of an olfactory
nature ; these areas may be spread over
nearly the whole of each joint, or confined
to one side or the end of the joint, and their
position affords one of the most important
characters used in the classification of the
family. The family is divided into three
principal groups — the Julodince, Chalco-

phorince, and Buprestince. The first group is chiefly restricted to Africa and the
East Indies. The Chalcophorince are more widely distributed, and include many
of the finest species of the family, such as the Euchronia gigantea of South
America, and the species of Catoxantha found in the East Indies. Chalcophora
mariana — figured on p. 145 — occurs in many pine-forests of the Continent, and
is one of the largest European species. The Buprestince are more numerous than
the other two groups, and are found in all parts of the world.

The click-beetles are, as a rule, narrower and more elongated than the

Polyphylla fullo, male (nat. size).

144

INSECTS.

Bwprestidce, and differ also in having the posterior angles of the pronotum sharply

produced behind, and the prosternal process laterally compressed and slightly

curved, with its point resting in a deep cavity in the mesosternum. Their antennae

— consisting of eleven, or rarely twelve, joints
— are usually serrate, though in many cases,
especially in the males, they are either pectinate
or flabellate. These beetles owe their name of
skip-jacks to the power they have, when fallen
on the back, of springing into the air and
alighting on their legs again. The larvae of
some species eat into soft succulent roots and
tubers, and in this way prove destructive to
many of our cultivated plants. These pests are
well-known to farmers under the name of wire-
worms. The larva of Agriotes lineatus is one
of the worst, being destructive not only in the
fields but also in the kitchen-garden. It is of
a pale yellowish brown colour, differing little
in general appearance from the larvae of other
species, and lives for probably four or five
years, passing then into a pupa, which remains
concealed in the ground for a few weeks before
changing into the perfect insect. Amongst the
exotic members of this family, the most remark-
able are the fire-flies, found in the West Indies
and America. There are several species of
these beetles, all belonging to the genus
Pyrophorus, one of which, P. noctilucus, is

illustrated on p. 146. They have a dark brown or reddish brown colour, obscured

by a covering of short grey hairs, and may be easily recognised by the

two slightly raised yellow spots placed near the

hind angles of the prothorax. In the living

insect these spots glow with a rich yellowish green

light. A stronger but more diffused light of

a reddish colour is given off from the abdomen

when the beetles are flying.

The remaining families of the section Penta-

mera are included in the tribe Malacodermata.

The beetles of this tribe are distinguished by

having the elytra less solid and compact, and the

body in general softer and more flexible than is

usual in other groups. The Lycidce are deserving of notice, inasmuch as they

form one of those groups of insects which are most frequently mimicked by species

of other families. They have a characteristic appearance, owing to the small

size of the head and prothorax, as compared with the greatly expanded elytra.

To their unusual shapes these beetles generally add a conspicuous coloration;

SUMMER-CHAFER (uat. size).

rhinoceros-beetle, male (cat. size).

COLEOPTERA.

M5

Ceratorrhina sviithi, male.

tawny yellow and red, varied in many cases with black spots and bands, being the

predominant colours throughout the family. They are found on the flowers and

leaves of trees, and are sometimes seen in great

abundance ; and it is said that they secrete a

nauseous liquid, which gives them immunity

from the attacks of insectivorous animals.

The Lampyridce are remarkable on account

of the luminous properties possessed by nearly

all the species. In these insects the head is

small and, being retracted under the pronotum,

generally invisible from above ; the eyes are

large, especially in the males, the mandibles

small but sharply pointed, and the antennae come

off close together from the front of the head.

The phosphorescent organs are situated in the

abdomen, their position being shown in most of

the species by pale yellowish or whitish areas

on the ventral surface of certain of the segments.
These beetles are found in nearly all parts of the
world, though most numerous perhaps in Tropical
America. In Lampyris and certain other genera
the females are frequently apterous. The female of
Lampyris noctiluca — our native glow-worm — is not
only without wings, but has even no trace of elytra,
so that in appearance it is not unlike the larva
of the same species, though it may be distinguished
by its broad semicircular prothorax, its more fully
developed legs, and much greater luminosity. In
the genus Lucicola — which is represented by two
or three species in South Europe — both sexes are
winged, and the males are even more luminous than
the females.
The Telephoridce are distinguished from the two preceding families in having

the head more exposed, the bases of the antennae more widely separated from one

another, the pronotum

somewhat square in shape,

the maxillary palpi ending

in a hatchet-shaped joint,

and the mandibles longer

and often bifid at the end,

or toothed on the inner

side. Some of them are

among the commonest and

most familiar of our in-
sects, — being known to

schoolboys as " soldiers "

VOL. VI. — IO

Chalcophora mariana and larva
(nat. size).

Agriotes lineatus and its larva — the well-known wire-worm,
enlarged, but the larva shown also nat. size. )

(Both much

146

INSECTS.

and " sailors," — and few of our readers can fail to recognise the species figured.
This species (Telephones fuscus), and a few others of the same genus, — some of

THE WEST INDIAN FIRE-FLY,

Pyrophorus noctUucus
(nat. size).

Telephones fuscus (slightly enlarged).

Trichodes apiarius
(enlarged).

which are of an almost entirely yellowish red colour, — are very plentiful on

flowers at certain times of the year.

The Cleridce are generally brightly coloured, of cylindrical form, with

the prothorax narrower than the elytra, the eyes notched in front, the antennae

either serrate, pec-
tinate, or clavate,
and the tarsi fur-
nished underneath
with membranous
lobes. Clems for-
micarius is very
abundant in pine-
forests, where it
plays a useful part in hunting for and
devouring wood - boring beetles ; while
the larva is still more active in following

under the bark the larvae of various kinds which are there

to be met with. The second species figured (Trichodes

apiarius) hunts for its prey on flowers, especially those of the

Umbelliferai, and the larvae are found in beehives, where they

devour many of the young brood.

The Ptinidos are all small insects, usually of a somewhat

cylindrical form, rounded at each end, and with the head

retracted under a hood-like covering, formed by the prothorax.

They are obscurely coloured and chiefly interesting on account the death-watch beetle,

,. ,, . , . ... t ji i i t)j • Anobium tessellatum

or their mischievous propensities, in the larval state rtmus (enlarged).

fur is very destructive in herbaria, and natural history

collections generally. The best known of the Ptinidce are the death-watch

beetles of the genus Anobium, to which we have already referred at the

beginning of this chapter. These beetles seldom show themselves openly, so

Clerus formicarius, with larva and pupa
(all enlarged).

COLEOPTERA.

147

that to most people they are only known by the sounds they produce, or the
holes with which the larvae riddle furniture and the woodwork of houses. The
holes with which old books are sometimes seen to be perforated are also made
by the larvae of a species of Anobium, which for this reason are known as book-
worms.

SECTION HETEROMERA.

The Heteromera are those beetles in which the tarsi of the fore and middle-
legs are five-jointed, those of the hind-legs being four-jointed. The Tenebrionidce
exceed in number of species the rest of the Heteromera together. The antennas
are inserted under a projecting angle or ridge on each side of the head, and
composed of eleven or,
exceptionally, ten joints,
of which the third is
generally the longest ; the
coxae of the front-legs are
usually rounded, with their
sockets separated by a
fairly broad prosternal
process, and completely
closed in behind ; and the
claws of all the tarsi are
simple. Many of the
obscurely coloured species
are without wings, and
frequently have the elytra
fused together. The

churchyard beetles (Blaps) and the meal-worm (Tenebrio) are probably the best
known members of the family. B. mucronata is the commonest species in England;
it differs from B. mortisaga, which also occurs, though rarely, in this country, in
having shorter points to the elytra. Of the genus Tenebrio two species occur in
Britain, one of which (T. molitor) is almost cosmopolitan in its range, having been
carried in flour to nearly every part of the world. The larvae,
known as meal - worms, are long and narrow, of a light
yellowish red colour, with the integument hard, and the last
segment conical in shape and ending into two slightly diverging
processes, armed each with a small black spine.

The Rhipidophoridce are a small but interesting family
of beetles in which the wings are always more or less exposed,
and not folded transversely as in most other groups, while the
elytra are either very short (as in the genera Rhipidophorus
and Rhipidius), or else triangular in form, meeting only at the
base and diverging from one another behind.

The Meloidce are chiefly distinguished from the other Heteromera by having
the head abruptly constricted behind in the form of a short neck, the coxae of the
anterior and middle legs long and prominent, and placed close to one another in

CHURCHYARD BEETLE AND LARVA (nat. size).

THE COMMON MEAL-WORM
AND ITS LARVA

(enlarged).

148

INSECTS.

the middle line, and the claws of the tarsi accompanied each by a slender hook, so
that they appear double. Many of the species possess vesicating or blistering
properties, and the family is for this reason sometimes known as the Vesicantia.
The larvae are interesting on account of their habits and the changes of form
they undergo in the course of their development. These changes are well illus-
trated in the case of the oil-beetles (Meloe). The larvse of these when first
hatched from the egg are active little creatures furnished with six legs. They
climb on to flowers, and wait in readiness to fasten themselves to the hairs of bees
coming to gather the honey. In this way they get carried to the nest, where they
devour the eggs of the bee. They now cast their skin, appear as little, maggot-like

OIL-BEETLES AND LARVAE (nat size).

grubs, with much reduced legs, and feed on the honey intended by the bee for its
own young. After a time they change to the form of a pupa, from which, instead
of the perfect insect, a third form of larva, somewhat similar to the second,
emerges, while a further change is still required before the true pupal stage is
reached. Seven species of Meloe occur in Great Britain, but, with the exception
of one or two, are very rare. When handled or irritated they exude an oily-
looking liquid of a yellow colour from certain of their joints. This secretion,
to which they owe their name of oil-beetles, has a burning, acrid taste.

The Stylopidce are remarkable little insects, which live parasitically in the
bodies of wasps, bees, and bugs, and present a type of structure distinct from

that of all other beetles. The male is a
winged insect, with coarsely - faceted
prominent eyes, large fan-shaped wings,
and extremely small inconspicuous elytra ;
the first two thoracic rings are very
short, while the metathorax is greatly
elongated and covers over the base of the
abdomen ; the hind-legs are placed a long
way behind the middle pair, and the tarsi
1, Xenospeckii— male ; 2, female. (Both enlarged.) of all the legs are membranous under-

COLEOPTERA.

149

ncath, and without claws at the end. The female, on the other hand, is a grub-like
creature, without legs, wings, or eyes. She never leaves the body of her host, and
from her eggs active little six-legged larvae develop, which make their way out
and get carried into the nests of bees and wasps, where they bore into the bodies
of the grubs. The Stylopidce are very rarely seen, and the number of species
known is small. They have been arranged in four or five genera, based upon
slight differences in the structure of the males, all of which have the general
appearance shown in our figure of Xenos peckii.

Sitones lineatus and
allied species.

SECTION TETRAMERA.

The Curculionidce or weevils are distinguished from all other beetles by a
few well-marked characters. The head is always produced in front in the form
either of a short muzzle or a more or less elongated and
narrow beak, which carries the mouth at its extremity ; the
prothorax rarely has sharp lateral edges, and the coxal cavities
on the under side of that segment are always closed in behind
by the extension inwards of the epimera to meet in the middle
line ; and the antennae are elbowed, with the first joint as a rule
long, and some of the joints at the end forming a club. Though
agreeing in a few essential characters, the weevils present
considerable variety, not only in the form and structure of
different parts, but also in the general shape of the body.
They have been arranged in a number of subfamilies, but it
is impossible in a limited space to describe the various modifi-
cations of structure on which these divisions are based, and we
must content ourselves here with a brief reference to some of

the typical and more interesting forms. In the genus
Sitones, we have examples of those weevils in which the
snout is short and comparatively broad. S. lineatus is
a well - known species which lives on papilionaceous
plants, and frequently does much mischief by devouring
the young leaves of peas and beans. It is a little
yellowish grey or drab-coloured beetle with three pale
lines along the thorax, and a number of rows of
punctures along the elytra. Its colour is due to a thick
covering of scales, some of which, when looked at closely,
are seen to have a golden tint.

Weevils are, as a rule, most destructive during the
larval state, the adult insects doing a comparatively
small amount of injury to vegetation; but as regards
Hylobius abietis, known as " the large pine-weevil," one
of the worst enemies of young conifers, the injury done
to the trees is altogether the work of the beetles, while
the grubs are quite harmless. The genus Apion com-
prises a large number of little, long - snouted weevils,

PINE-WEEVIL, WITH LARVA AND
PUPA.

150 INSECTS.

having in general the form shown in our figure of A. apricans. Though the
British species are numerous and some of them common everywhere on clover,

trefoil, and other leguminous plants, they are
seldom noticed owing to their small size. In
Apoderus, Attelabus, and Rhynchites we have a
group of genera which are interesting on account
of the leaf- rolling habits of the females, and
remarkable also, in the case of the first genus, for
the great length of neck displayed by some of
the species. The females deposit a single egg, or

Avion apricans (nat. size and much • ,, , „

enlarged). m some cases two or even three eggs in each of

the little rolled -up leaf packages, which serve

afterwards both as a shelter and food-supply for the larvae. Three or four species

of these leaf-rolling weevils are found in Britain. Our figure of A. longicollis,

lorvn.

LEAF-ROLLING WEEVILS.

1, Attelabus curculionoides ; 2, Apoderits coryli ; 3, Rhynchites betuleti ; 4, R. populi ; 5, R. betulce. (Nat. size.)

a Javan species, shows what an extraordinary length the neck may attain in

the males of some of the tropical representatives of the genus, although in this

species it is not nearly so long in proportion as in an allied form (A. tenuissimus)

found in the Philippine Islands. The nut -weevil (Balaninas

nucum) affords a strong contrast in the shape of its head to the

species just mentioned. It will be noticed that in this weevil

the head is very short behind the eyes, whereas the beak is

greatly elongated, with the antennas inserted near the middle of

its length. The female lays her eggs in hazel-nuts while the

latter are still in a half-developed condition ; she first pierces a

hole in the soft shell of the nut, and then depositing an egg in

the opening pushes it in with her beak. The grub feeds inside

the nut, remaining in it until autumn, when it bores a round

aperture in the shell, and, escaping from the nut, makes its way

into the soil, where it surrounds itself with a cocoon formed of

Apoderus longicollis
(enlarged).

COLEOPTERA.

fragments of earth. The " apple -blossom weevil" (Anthonomus pomorum) is
another species which, on account of its injurious habits, deserves some notice. It

NUT-WEEVIL AND ITS LARVA.

PEAR-BLOSSOM WEEVIL, WITH LARVA AND

pupa (enlarged).

is about a quarter of an inch long, of a
greyish brown colour, with an oblique
white band on the elytra, and three
whitish lines on the thorax. The female
deposits her eggs in the unopened flower-
buds of the apple, and the larva by feeding
on the stamens and pistil causes the bud
to wither and die. In about fifteen days,

the larva attains its full size, changing then to a pupa within the bud, and the

beetle appears about eight days later and escapes through an opening which it

makes in the side. A closely allied species

(A pyri) proves injurious in the same way

to pear blossoms. The cabbage -gall weevil

(Ceuthorrhynchus sulcicollis) and certain species

of Baridius attack cruciferous plants ; the

larvae of the former live inside galls which

they raise on the roots of cabbages and turnips,

while those of Baridius may be found living in

the lower part of the stem. The grain-weevils,

which are most numerous in tropical countries,

are represented in Britain by two almost cosmopolitan species, the corn-weevil

{Sitophilus granarius), and the rice-weevil (S. oryzce). These are both small

apple-blossom weevil (nat, size
and enlarged).

1, Ceuthorrhynchus sulcicollis ; 2, C. assimilis ; 3, Baridius chloris ; 4, B. cuprirostris.
(The beetles all enlarged.)

INSECTS.

palm-weevil (uat. size. )

species, but belong to a subfamily (the Calandrince), which includes a number of
the largest tropical weevils, such as the palm-weevil (Rhyncliophorus palmarum).

The Scolytidce and two other small families, the
Brenthidce and Anthribiclce, are associated with the
weevils in the tribe Rhynchophora. The Scolytidai
are little beetles which live under bark, and often
prove very injurious to trees. They have four
jointed tarsi, clubbed antennae, and the head pro-
duced in front into a short muzzle. The females
lay their eggs along the sides of galleries which
they burrow out under the bark ; the larvae when
hatched make tracks at right angles to the mother-
galleries, and thus form curious and characteristic
patterns.

The Cerambycidce, or Longicorns have in most
cases a characteristic appearance by which they may
be easily recognised, though, owing to a great variety
in their form and structure, the family as a whole
is not easily defined. Thus the great length of the
antennae to which these beetles owe their name is not always a distin-
guishing feature, for in many genera the antennae are much shorter than
the body. The Longicorns resemble the Rhynchophora in having the first
three joints of the tarsi furnished underneath with a brush-like covering of
hairs, and the fourth joint very small and hidden between the lobes of the
third; but they are distinguished from that tribe by the fact that the epimera
of the prothorax do not meet,
while the head, though some-
times produced into a short
muzzle, is never prolonged in
the form of a beak. The larvae
all have a strong family like-
ness, and are quite unlike those
of the Chrysomelidce. They
are of a dirty-white or pale
yellow colour, with a rather
soft skin, and in general form
most resemble the larvae of
Buprestidce. These larvae all
live in the interior of plants;
some feeding just under the
bark, while the great majority
bore tunnels in the woody tissue, or live exclusively in the pith. The males have as
a rule longer antennae than the females, and may often be distinguished by the
larger size of the eyes, jaws, or prothorax, or the greater length of the legs. The
females are provided with a flexible ovipositor, which can be protruded some distance
beyond the end of the body. In the subfamily Prionince the anterior coxae are

Hylotriipes bajulus, with larva (nat. size).

COLEOPTERA.

153

strongly transverse, and their sockets widely open behind, the sides of the prothorax
are sharply edged, the palpi are never pointed at the end, and the front tibiae are
without a groove underneath. This subfamily is the least numerous in species,
though many of these are distinguished for their great size. Titanus giganteus, a
Brazilian species, sometimes measures over half a foot long, and is the largest of all
known beetles, while the sawyer-beetle (Macrodontia cervicornis) and other species
occurring in Tropical America, are not much smaller. Most of the Prionince are
found in the warmer parts of the world. They are represented in Europe by
Prionus coriarius, Ergates faber, and a few other forms. P. coriarius is the only
species which occurs in England, and is not very common, being met with chiefly
in oak-woods, where the larvae live in the rotten trunks of trees. The Ceram-

Prionus coriarius, female ; and Ergates faber, male (nat. size).

bycince are widely distributed and include a very large number of species. They
are as a rule narrower than the Prionince, and without sharp lateral edges to the
prothorax, while the sockets of their front-legs are seldom strongly transverse and
are often rounded and completely closed behind. Most of the species have a
stridulating area on the mesonotum, and by this means are enabled to produce
sounds. This subfamily includes a number of very remarkable mimetic forms,
some with broadly expanded elytra, and black and tawny colours resembling
Lycidce, others with the elytra greatly reduced in size, and the shape of the body
modified in imitation of various Hymenoptera. The metallic-coloured beetles of
the group Callichromides, most of which are found in tropical countries, exhale a
scent resembling otto of roses. In England this group is represented by the musk-
beetle (Aromia moschata), figured on p. 154, a handsome insect of a golden-green
or bronzy colour, which is met with on willow-trees. Amongst the European species of
Cerambycince, the groups Lepturides, Molorchides, and Clytides are best represented.
Some of the Lepturides, such as Strangalia and Toxotus are flower-frequenting

i54

INSECTS.

insects, others like Rhagium are found on the trunks of pine-trees. In the
Molorchides the elytra are usually short or very narrow, and the abdomen slender

and constricted at the
base, so that many of
the species have a re-
semblance to Hymen-
optera. The European
Necydalis major looks
like a hornet, but in
many of the tropical
forms these resem-
blances are more pro-
nounced. The Clytides
are found on flowers,
chiefly of the umbell-
iferous kind, and two or
three species are among
the prettiest of British beetles.

Some of the
Clytides and species of Hylotrupes and Callidium
are occasionally met with in houses, being intro-
duced in the wood in which the larvae feed. The
Lamiince are more numerous than the other
Longicorns, and distinguished by having an
oblique groove on the lower side of the front
tibiae, the last joint of the palpi usually pointed
at the end, and the front of the head in most
cases turned down vertically, or sometimes even inclined backwards, bringing the
mouth close to the prosternum. The species of the genus Lamia are few in
number and by no means typical of the subfamily ; they are clumsy-looking, dull
black insects, one of which (Lamia

Strangalia armata and larva
(nat. size).

1, musk-beetle : 2, Spondylis buprestoidcs
(nat. size).

textor) is found on willow-trees and in

osier-beds in some parts of Britain. In

the genus Acanthocinus the antennas

attain their greatest length, being four

times as long as the body in the male.

A. osdilis is found in pine -woods in

Scotland, and is met with occasionally

in other parts of Great Britain and

even in London, where it is sometimes

introduced in timber. Amongst the

exotic species of this subfamily, the

harlequin - beetle (Acrocinus longi-

manus) is one of the most remarkable,

being distinguished, not only by its curiously variegated colours, but also by the

extraordinary length of the front legs in the male.

The Bruchida? are a small but widely spread family of little beetles which are

Toxotus meridianus, male and female (nat. size).

COLEOPTERA.

155

found chiefly on leguminous plants,
internal parts and changing to pupee
one time classed with the weevils,
but are now generally recognised
as being more nearly allied to the
next family. They are illustrated
on p. 1, where Fig. 1 is the pea-
bruchus (Bruchus pisi); Fig. 2,
the bean-bruchus (B. rufimanus) ;
and Fig. 3, B. granarius, and
larva ; all of them being enlarged.
The Chrysomelidce, more com-
monly known as the Phytophaga
— though this name is equally
applicable to many other beetles
— all live upon plants, feeding
chiefly upon the foliage, while some
also attack the flowers. They are
almost as numerous as the weevils,
and in their own way quite as
destructive to vegetation. The
family is divided into four sections.
The Eupoda include those forms
which most resemble the Longi-
corns. Many of the beetles belong-

The larvae live in the seeds, eating up all the
within the outer shell. These beetles were at

Necydal

1, Rhagium indagator, with larva and pupa-case ;
2, Rhagium bifasciatum. (Nat. size.)

ing to this section have
thickened hind-legs, but
instead of being active
jumpers, as might be
suspected, they are really
very slow and awkward
in their movements. In
the males of the genus
Sagra, the hind-legs are
enormously developed,
the species of this genus
being for that reason
sometimes known as
kangaroo -beetles. The
Donacince live upon
aquatic plants of various
kinds; they have a
bright metallic colora-
tion, which in many
species is veiled by a
delicate covering of

i56

INSECTS.

silky hairs, and their elytra are marked with rows of deep punctures. The larvae
feed under water upon the roots of the plants, and change to pupae which are

1, Lamia textor ; 2, Female of A. cedilis ; 3, Male of Acathocinus cedilis ; 4, Saperda carcharias ;
5, S. popidnea. (All nat. size.)

enclosed in oval cocoons. In the beetles of the section Camptosomata, the body is
short, the head vertical and deeply sunk in the prothorax, and the abdomen slightly

curved, with its middle segments con-
tracted ; the antennae are short and serrate
or pectinate in the first subfamily, while
in the second they are rather long and
filiform. The larvae move about sur-
rounded by a sack -like case, from which
the head and anterior part of the body are
free. They retract themselves completely
within the case and close up the opening
when about to undergo their metamor-
phosis. The Cyclica comprise four sub-
families, of which the first, the Eumolpince,
is almost entirely composed of exotic
species, though one of the few species
found in Europe (Bromius vitis) is only
too well-known on account of the damage

Bonacia clavipes, with larva and pupa case
(nat. size).

it inflicts on the leaves of the vine. With
the Chrysomelince we come to the most
typical forms belonging to the family.
These beetles are distinguished by their oval and convex shapes, having in many
cases a great resemblance to lady - birds (Coccinellidce), while their colours are

COLEOPTERA.

157

nearly always brightly metallic or otherwise conspicuous. Some of the species

are very gregarious in their habits. Lina tremuke is often found in large numbers

in all its stages on the leaves of aspen ; the larvae are

somewhat like those of lady-birds, and have the habit

of exuding a strong -smelling yellow liquid from the

mouth and other parts of the body. The Colorado

potato - beetle (Lejrtinotarsa decemlineata) is very

destructive to the potato crops in North America. The

Galeriicince are poorly represented in Great Britain,

while of the flea-beetles {HalticincB) we have a large

number of species, of which the bes£ known are the

turnip -flea (Phyllotreta nemorum), and other little

jumping beetles which attack cruciferous plants. The

larvae of the Halticince usually mine in the tissues of

the leaf underneath the epidermis ; in this respect

differing from the larvae of most of the other

Chrysomelidce. The Cryptostomata are distinguished

by having the front of the head inclined backwards

so that the mouth is almost completely hidden. Two

subfamilies are included in this section. The Hispincv

are remarkable for the sharp projecting spines with

which many of the species are armed, while the

Cassidince have the characteristic form to which they

owe their name of tortoise-beetles. In Great Britain,

the tortoise-beetles are represented by half a dozen or more species of the genus

Cassida, one of which (C. nebidosa) in its different stages is illustrated in our figure.

COLORADO POTATO-BEETLE IN ALL

its stages {nat. size).

LIFE-HISTORY OF THE TORTOISE-BEETLES (Cassidince).

1, Cassida nebidosa ; 2, The beetle (enlarged) ; 3, The larva Cnat. size) ; 4, The pupa, and 5, the larva (both
enlarged) ; 6, Desmonota variolosa, with leg and portion of elytron enlarged.

A Brazilian species (Desmonota variolosa), remarkable for its deeply sculptured
elytra and bright golden-green colour, is also shown in the same figure.

158

INSECTS.

SECTION TRIMERA.

Two families, of which one only need be noticed here, are included in this
section. The Coccinellidce, or lady-birds are so familiar to everyone that it is quite
unnecessary to describe their general appearance. They are resembled in shape
by some other beetles, but in such cases the lady-birds may be distinguished by their
three-jointed tarsi, clubbed antennae, and the hatchet-shaped terminal joint of their
palpi. These charming little insects have always been held in much respect, as the
different names given to them testify, and it is well that it should be so. For
while the species of a few genera (Epilachna, Lasia) are herbivorous in their
habits, the great majority live — especially in the larval state — upon green-fly and
plant-lice, and, by keeping these noxious insects in check, perform a useful service
to man. The lady-birds are found in nearly all parts of the world, and over a

6

LADY-BIRDS.

1, Micraspis duodecimpunctata (nat. size and enlarged) ; 2, Coccinella septevipunctata ; 3, Larva (enlarged) ; 4,
C. impustulata ; 5, 0. bipunctata and dark variety ; 6, Chilocorus bipustidatus.

thousand different species are known. Among several species occurring in Britain
the two commonest are, perhaps, the large seven-spotted Coccinella septempuncta
and the small two-spotted C. bipunctata. The latter varies in colour to a
great extent, so that between the typical form with red elytra marked with two
black spots, and others in which the elytra are entirely black, one meets with
almost every intermediate condition. The larvae of these species may often be
seen walking about on leaves that are infested with green-fly. They may be
recognised by their slate-blue colour, marked with some yellow dots, and by the
greed with which they devour the aphides. The larvae, when about five or six
weeks old, are ready to pupate. Fixing themselves by the tail-end to a leaf, they
cast their skin, and the pupae, resting upon the cast-off larval skin, remain attached
to the leaf. The beetles emerge about eight days later, so that the whole course of
development from the egg to the perfect insect is completed in less than a couple
of months.

C. J. GAHAN.

CHAPTER V.

Jointed Animals, — continued.

Insects, — concluded.

Orders Neuroptera, Orthoptera, Rhynchota, etc.

Characters of The Neuroptera form the last order of insects which undergo a
the Neuroptera. complete metamorphosis in the course of their development. In this
order it was formerly usual to include certain groups of insects, such as the dragon-
flies, May-flies, white ants, etc., none of which pass through a period of prolonged
inactivity, or pupal-stage, before reaching the perfect condition. But although it
is largely a matter of convenience whether these groups be placed, as they are in
this work, in the order Orthoptera, or arranged in a series of separate orders, no
one, taking into consideration the great difference in their mode of development,
would now think of associating them in the same order with the true Neuroptera.
The adult insects of the present order have their mouth-organs, when fully
developed, adapted to biting and grinding, and never formed for piercing or suck-
ing ; in which respect they differ from three of the other orders of the metabolous
insects, namely, the Hymenoptera, Diptera, and Lepidoptera. From the Coleoptera
they are easily distinguished by the structure of their fore-wings, which are never
hard and horny like the wing-cases or elytra of the latter. Both pairs of wings
are membranous, and usually traversed by numerous, more or less closely reticu-
lating, veins ; whence the name of Neuroptera given to the order. The hind-wings
are often very similar to the fore-wings, but sometimes differ considerably in size
and shape. In one section — the caddis-flies — they are capable of being folded like
a fan, but in the other section (Planipennia) they always remain flat, and are
spread horizontally or obliquely in repose.

Caddis-Flies, — Suborder Trichoptera.

The caddis-flies, forming the first of the two great divisions of the order, are in
general appearance rather like some of the smaller kinds of moths ; and since they
differ a good deal from the typical Neuroptera, they are often treated as a distinct
order. In their adult state they have two pairs of wings, in which the neuration
is comparatively simple, with few transverse nervures. The wings are generally
clothed with hairs, and the hind-wings usually shorter, broader, and less hairy than
the front pair. When at rest, the hind-wings are folded fan-wise, with the fore-
wings covering them over like a roof. The caddis-flies have a rather small head,
which bears two long, tapering, and many-jointed antennas. They have round and

i6o

INSECTS.

prominent eyes, and usually also three ocelli, placed on the forehead. With the
exception of the palpi, their mouth-organs are feebly developed. Their legs are
long, and possess five-jointed tarsi ; and the tibiae are generally furnished with
spurs, whose number and disposition are of considerable value in distinguishing
the genera. These insects fly chiefly in the evening or at night, and, attracted by
the light, frequently enter houses ; some of the smaller species flying in swarms
over water. The larvae, with few exceptions, are aquatic in their habits ; some
being carnivorous, although most feed on vegetable matter. Found in streams,
lakes, and ponds, or any piece of water in which plants grow, caddis-worms, as the

VARIOUS FORMS OF CASES MADE BY CADDIS-FLY LARV.E.

1-5, Cases composed of sand and pebbles ; 6, A case made of small snail-shells ; 7-10, Cases made of

different parts of plants.

larvae are called, are well known to anglers, by whom they are frequently used as
bait. The eggs from which they are hatched are laid sometimes in the water, or
on aquatic plants or trees overhanging water. Females have occasionally been
captured with a coating of dry mud on their abdomen, showing that they had gone
to some muddy pool to lay their eggs. The cases, made out of all sorts of materials,
with which many of the larvae surround their bodies, have long been objects of
interest to the naturalist. Some larvae pick up bits of sticks and leaves, grains of
sand, and fragments of shells, or whatever else comes handiest, and fasten them
together in a rough sort of fashion ; but many exercise a choice in the selection of
materials, and exhibit great dexterity and neatness in piecing them together. The

NE UROPTERA. 1 6 1

shape of its dwelling, and the nature of the materials used, are often characteristic
of the family, sometimes of the genus or species, to which a larva belongs. In the
family Phryganeidcu, for example, the larvae construct their cases with bits of
leaves or twigs, cut into suitable lengths, and arranged side by side in such a
manner as to form a spiral band passing many times around the case (see No. 7 in
figure). The species of Limnopkilus fashion their cases in various styles ; the
larvae of L. pellucidus using entire leaves, so that the case may have a flattened
form, wide in proportion to its depth. The cases made by L. rhombicus consist of
bits of sticks or fibres placed transversely, with shells sometimes added ; while
those of L. Jiavicornis are often built almost entirely of the shells of different small
molluscs, more especially those of Planorbis. What is still more remarkable about
these cases is the fact that the case-worms do not necessarily select empty shells,
but take those with living occupants as well, and fasten them all together around
their backs. Grains of sand, of finer or coarser kind, are used by many larvae in
the construction of their cases ; and the latter may be either cylindrical in form or
slightly curved, or, as in the exotic genus Helicopsyche, they may, like snail-shells,
have a distinct spiral curvature. The grubs of other species arrange bits of sticks
transversely in four different directions, using longer pieces as they progress, so
that the complete case is four-sided, with the sides gradually widening from one
end to the other ; and there is a type in which the four sides, instead of being
straight, are carried round in a gentle spiral curve. The interior of each larval
case is a tubular chamber, lined with silk, open at each end, and about wide enough
to enable the larva to turn inside. At the fore-end, which is generally a little
wider, the head, thorax, and the six legs of the larva may be seen projecting ;
whereas the hinder end is usually closed by a silken partition pierced with holes.
The body of the naked larva is made up of a number of segments, of which the
first three — carrying the legs — are, like the head, hard and of a brownish colour ;
while those that follow, about nine in number, are soft, white, and partly trans-
parent. On the last segment are a pair of horny hooks, which enable the
larva to grip tightly to its case. On the first abdominal segment three fleshy
protuberances are often seen, — a longer one above and a shorter one on each
side, — which appear to be used in enabling the larva to steady its body in the
case, and to regulate its position with regard to the sides, so that the water
necessary for breathing may pass freely in and out. The larva breathes by
means of rows or tufts of soft white filaments — the tracheal gills — attached to
the sides of all the abdominal segments except the first and last, and differing
in arrangement in different species. Previously to entering the pupal stage, the
larvae of many species provide for their protection during that inactive and help-
less period of their existence. They shut themselves up in their cases, some by
closing the openings at each end with sieve-like plates of silk, which, while allowing
free access to the water necessary for breathing, may serve to keep out their enemies ;
others by placing stones loosely over the openings, and so accomplishing the same
purpose. There are a few larvae, moreover, which, in their earlier days, make cases
out of leaves, but add stones as they grow older, until just before pupation begins
the case is entirely made of stones. Before the pupa is transformed into the
perfect insect, it extricates itself from its case, and leads an active life, swimming
VOL. vi. — II

l62

INSECTS.

and running with agility. It then climbs up the stem of a plant to undergo
its transformation. In some of the smaller species the pupa does not leave the
water, but rises to the surface, and the fly emerges from the floating pupal skin.

Caddis-flies are divided into seven families, arranged in two groups chiefly
distinguished by the number of joints in the maxillary palpi of the male insect.
In the first section — Inaequipalpia — the maxillary palpi of the male are composed
of two, three, or four joints, never five ; thus differing from those of the female, in
which the number of joints is always five. This section contains four families —
the Phryganeidce, Limnophilidce, Sericostomatidce, and Hydroptilidai ; the life-

LIFE-HISTORY OF THE CADDIS-FLY.

1, Larva ; 2, Pupa ; 3, Larva in its case ; 4, Perfect insect.

history of a species of the typical genus (Limnophilus) being depicted in our illus-
tration. The second section — ^Equipalpa — is characterised by the fact that the
maxillary palpi of the male are five-jointed like those of the female ; it includes
the families Leptoceridce, Hy dropsy chidce, and Rhyacojihilidce.

Flat- Winged Group, — Suborder Planipennia.

The members of this group are distinguished from the last by having both
pairs of wings formed nearly alike, and usually provided with a closely reticulated
system of nervures, with numerous transverse branches. The wings — which are
incapable of being folded up — are for the most part naked ; and, when at rest, are
turned back in a slanting position against the sides of the body. The mouth-organs
are well-developed, the mandibles in some cases attaining extraordinary proportions.
The first family is that of the scorpion-flies (Panorpidce), which have a slender
body, and the head turned downwards and prolonged in the form of a beak,
resulting from the elongation of the clypeus in front, and of the lower lip
and maxillae behind. The mandibles are rather short and narrow ; the maxillae,
which are fused with the mentum, have five-jointed palpi ; and the narrow lower
lip is bifid at the extremity, with three-jointed palpi. The antennae are setiform,
and inserted between the rather prominent eyes, and below the ocelli, which are
usually distinct. The prothorax is short and collar-like ; and the wings of these

NEUR0P1ERA.

163

insects are less closely reticulated, and have fewer transverse nervures than those
of the other groups. The common scorpion-fly {Panorpa communis), which may
be taken as the type of the family, is a shiny black insect about half an inch or more
in length, with long, transparent, spotted wings, and a yellow beak and legs. The
three last body-segments of the male are narrow, and can be curved like a tail, and

COMMON SCORPION-FLY.

a, Female depositing her eggs ; b, Male ; c, Larva ; d, Pupa.

have a reddish colour ; and the last carries a pair of pincer-like claws. It is from
this circumstance that the insect has received its name, though it does not possess
a sting like a scorpion.

In the snake-flies and alder-flies (Sialidce), forming the second family, the
head is comparatively large, and often
inclined in front, but never elongated in
the form of a beak. The antenna? are
bristle-like, and not so long as the body ;
the prothorax being strongly developed.
The camel or snake-flies (Rhaphidia) have
the head long and narrow behind, and freely
articulated with the long and narrow pro-
thorax. The latter can also move freely
at its articulation with the segment
which follows; and this explains how the
prothorax is raised, and. the head bent
forward in the characteristic attitude which
these insects adopt when about to seize
their prey, which consists usually of various
small insects.

The alder - fly, or May - fly (Sialis
lutaria), is at first sight rather like a
caddis-fly, but has a stouter body, and may
be distinguished by its more completely
developed mouth-organs, as well as by the
different structure of its wings. It emerges
from the pupa about May or June. The
winged insects fly slowly and heavily, and
are to be met with about trees and shrubs,
or walls and palings, at no great distance
from water. The female, which is somewhat larger than the male, lays her eggs
in patches on a plant or other object in the vicinity of water. There may be

LIFE-HISTORY OF THE ALDER-FLY.

1, Eggs ; 2, Larva ; 3, Pupa ; 4, Imago.

Ib4

INSECTS.

several hundred eggs packed closely together in a single cluster; they stand
upright, being cylindrical in form, with rounded ends, and each terminating above
in a little white projection. The larvae hatch in a few weeks, and then find their
way into water, where they creep on the mud in search of the aquatic creatures on
which they feed. When full-grown, they are about an inch long, with a body
tapering slightly towards the head, and, more gradually, towards the long and
narrow tail. The head and three thoracic rings are horny, the rest of the body
having a softer integument. The larva, which has strong legs and can walk well,
breathes by means of tracheal gills, having the form of jointed appendages attached
in pairs to the sides of the first seven abdominal segments. When the time for
pupation arrives, generally about May or June, the larva leaves the water and
seeks a place to bury itself in the earth. Having excavated a little cell, it throws
off the larval skin and becomes a pupa, which has the legs and wings free from

LIFE-HISTORY OP THE COMMON ANT-LION.

a, Imago ; b, Larva ; c, Pupa (nat. size).

the body, but enclosed in special sheaths. After a few weeks longer it is trans-
formed into the perfect insect.

The lace-wing flies, ant-lions, mantis-flies, and some other families, have been
associated in a third group of Planipennia, to which the name Megaloptera is
given. In all, the wings are relatively large and closely reticulated ; the prothorax
being variable in size and form, and the joints of the tarsi not dilated. The mantis-
flies (Mantispidce) take their name from the shape of the fore-legs, and their
position near the front end of the long prothorax ; in which respect they resemble
the mantis or praying insect. One species is common in South Europe. The larvae
live parasitically in the nests of spiders and tree-wasps ; and while they are at first
free and active, they afterwards become almost legless, like those of certain beetles.
The allied family Nemopteridce is mainly characteristic of the countries around

NEUROPTERA.

161

the Mediterranean Sea. These insects have elongated and narrow, or almost linear,
hind-wings, often widened out a little before the tip. The ant-lions (Myrnieleontidce)
may be recognised by their clubbed antennae, and their long and closely reticulated
wings, rounded off to an obtuse point at the extremity.

Of the European species the common ant-lion {Myrmeleon formicarius) is one
of the best known. It lives in pine-woods. The winged insect, which may be
seen in July and September, rests during the day clinging to a plant, with its
wings spread like a roof over the hind-part of its body. At sunset it becomes
active, and executes a slow flight in its search after food or a mate. The larva,
to which the name ant-lion properly belongs, has the habit of making pitfalls
to entrap its prey. It is somewhat oval in the shape of its hind-body, and has
a narrow prothorax resembling a neck, and a rather big head, provided with a
pair of long, curved, and sharply pointed mandibles, each of which has three teeth
on the inner side. Its body is arched up in the middle, and has wart-like pro-
tuberances, thickly covered with hairs, at the sides. When about to make a pit,

LACE-WING FLIES.

1, Chrysopa vulgaris ; 2, The tip of its wing ; 3, Larva ; 4, Pupa ; 5, 6, Cocoon ; 7, Egg ; 8, Hemerobius hirtus.

it selects a dry and sandy spot, and begins by tracing out a circular furrow to
mark its outer limit. Placing itself inside the circle, it buries its abdomen in the
sand, and then proceeds with the work of excavation. With one of its fore-legs it
shovels the sand on to its large flat head, to which it then gives a sudden jerk, and
sends the sand out over the border. It repeats this process, walking backwards
and maintaining a spiral course all the while, until finally it reaches the centre of
the cavity. Sometimes, however, instead of continuing to work altogether in one
direction, it turns round and works the opposite way, thus giving relief to the
leg which had previously been employed. And, as the sand is always taken from
the inner side, it is the leg on that side which is always used as a shovel. The pit,
when completed, is shaped like the mouth of a funnel, being wide above and
gradually narrowed to the bottom. Its size is adapted to the size of the larva,
which when full grown makes a pit about two inches deep, and three inches wide
at the top. Buried in the sand at the bottom, with only its antennae and the tips of
its mandibles projecting, the ant-lion waits until an ant or some other creature falls
down the loose sides of the pit, when it is immediately seized with the pincer-like
jaws, and retained until all the juices of its body have been sucked out, and nothing
left but the dry and shrivelled skin. The latter is cast outside the pit, and the

1 66 INSECTS.

larva again lies in wait. If by chance the victim should escape the first onslaught,
and endeavour to scramble up the sides of the pit, its attempt is soon frustrated, for
the ant-lion throws up sand with its head, causing the victim to tumble once more to
the bottom.

The lace-wings flies (Hemerobiidce and Chrysopidce), are smaller and more
delicate insects than the ant-lions, and have setiform antenna?. The golden-
eyed fly (Chrysopa vulgaris), figured on p. 165, may be taken as a typical species.
It is slender, with long and richly-veined wings of a tender green colour, as
is also the body. Its antennas are long and tapering, and its prominent eyes
shine like hemispheres of gold. The larvae of the lace-wings are not unlike the
ant-lion, although somewhat longer and narrower in proportion to the size of
their bodies, and less hairy. Their mandibles, moreover, have no teeth on the
inner side. In their carnivorous habits they resemble ant-lions, but instead of
making pits and remaining stationary they rove about in search of their prey,
which consists of the different kinds of green-fly and plant-lice.

Order Orthoptera.

This order being taken to include, not only the true Orthoptera, but various
other groups formerly placed in the Neuroptera, and hence known as Pseudoneurop-
tera, it is necessary in defining the group to mention only such characters as are
common to the whole of these insects. None of the members of the group undergo
a distinct metamorphosis ; the development from the larval to the adult condition
taking place by a succession of changes, and the perfect insects being distinguishable
from advanced larvae by little more than the possession of complete wings. The
wings are, however, in some cases confined to one sex, while in others they are
altogether wanting in both sexes. The mouth-organs, when not reduced to
a functionless condition, are adapted to biting ; the lower lip (labium) is nearly
always divided in the middle at its free end, and each of the two halves often sub-
divided into a pair of lobes. On the floor of the mouth, concealed by the labium,
there is, as a rule, a membranous or more or less horny structure, known as the
tongue (lingua), or hypopharynx, which is free from the labium in its anterior part.
Though poor in the number of species, as compared with some other orders, the
Orthoptera contain many of the most interesting forms of insect life ; some, like the
leaf and stick-insects, remarkable for their size and the variety of their protective
disguises, others, as the white-ants, for the wonderful development of their social
habits. The day-flies are noted for the shortness of their lives, the dragon-flies for
their beauty ; while many other forms are well known from some particular feature
or habit. In past epochs of the earth's history Orthoptera were well represented,
their remains being found in rocks of various ages extending back to Palaeozoic
times. The oldest reputed insect is known by the impression of an orthopterous
wing (Palceoblattina), from the Silurian sandstone of Calvados in France. There
is some doubt as to which group of the order the insect belonged, and even as to
whether the impression owed its origin to an insect at all. However this may
be, traces of undoubted Orthoptera, as well as of Neuroptera, are met with in rocks
of Devonian and Carboniferous ages. The Orthoptera of the latter period included

ORTHOPTERA. 167

numerous cockroaches (Blattidw), together with stick - insects, ephemerids, and
dragon-flies, some of which greatly exceed in size any existing form. One of the
dragon-flies (Meganeura monyi), was 13 inches in the length of its body, and each
of its wings was quite a foot long.

The Pseudoneuroptera are distinguished from the Neuroptera by the absence
of a pupal stage. While agreeing in this respect with the typical Orthoptera,
these insects differ by certain characters not generally considered of the first im-
portance. Both pairs of wings in this group are thin and membranous, resembling
one another in structure, and the hind-wings do not fold up ; whereas in the true
Orthoptera the fore-wings are usually thicker and harder than the hind-wings,
and the latter are capable of being folded like a fan.

The first group is that of the dragon-flies (Odonata), the general
appearance of which is too well known to need description. All have
a large head, the sides of which are covered almost entirely by the two big, glassy-
looking, compound eyes, while on its crown are two or three small simple ocelli.
Each of the short and bristle-like antennae has a stouter basal portion by which it
is inserted on the forehead. The mouth faces downwards, and has a large semi-
circular lip (labrum) in front ; the jaws being strong, horny, and well provided
with teeth. The maxillae are without palpi, but their narrow and palp-like outer
lobe is often regarded as the real palp. Succeeding the jaws behind is the lower
lip (labium), which at its free end is usually slightly cleft in the middle, while its
palpi take the form of two dilated and often two-jointed lateral lobes ; these lobes
sometimes overlapping one another in front to hide the free end of the lip. The
thick and cylindrical thorax is followed by a long slender abdomen, which usually
carries at the end two leaf -like or pincer-like appendages. When looked at from
the side, the two hinder segments of the thorax appear oblique, with the wings set
rather far back above, and the legs pushed forward below. The wings are long,
transparent, and traversed by a rich network of veins. The legs are often spiny,
and their tarsi are always three-jointed. The position of the accessory organs of
the male on the under side of the second abdominal ring is a feature distinguishing
dragon-flies from other insects.

The female dragon-fly deposits her eggs in such a position that the larvae, when
hatched, find themselves either in their natural element, the water, or very close
to it. In some species the female, accompanied by the male, goes under the water
to lay her eggs ; others drop them into the water ; while in many species the
female makes incisions in some aquatic plant and there deposits her eggs. The
larvae are even more fiercely carnivorous than the adult, and are distinguished
from all other aquatic larvae by the possession of a peculiar structure fixed under
the head, known as the mask. In their mode of respiration dragon-fly larvae are
also peculiar, some being provided with external tracheal gills— in the form of
three leaflets placed near the tail-end — which serve also to assist in locomo-
tion, while others breathe by means of gills of an exceptional character.
The latter are situated in the hinder part of the intestine and consist of six
longitudinal bands in its walls, crossed by several transverse folds, supplied
with numerous fine branches from the tracheal trunks. Water can be sucked
in at the opening, guarded by five valves at the hind end of the body, and

i68

INSECTS.

when it becomes vitiated can be squirted out again either gently or with con-
siderable force. When it is suddenly and violently expelled, it serves to propel
the insect forwards at a rapid rate. The larvse live about ten or twelve
months, during which time they undergo several moults; rudiments of wings
appearing some time before the final transformation. When this is about to
take place, the larva leaves the water by climbing the stem of a plant, or to
some other dry spot. As the time approaches, its eyes, which were before dull
and opaque, become bright and transparent. Its skin dries up, and soon begins
to crack along the middle of the thorax; the thorax appears through the cleft,
and swelling up causes it to extend ; the head is next disengaged, and the legs
are then drawn out of their sheath. The insect now throws its head farther
and farther back, and by this means gradually frees the hinder part of its
body, with the exception of the last few segments which still remain enclosed in
the larval skin. After a while, it suddenly bends its body forwards, grasps the

12 3 4 5

LIFE-HISTORY OF DRAGON-FLIES.

1, Larval skin of a dragon-fly ; 2, Larva with its mask exserted ; 3, Libellula depressa ; 4, Advanced larva
of a libellula ; 5, The same about to undergo its final transformation.

sides of the sheath with its legs, and, doubling up its abdomen, finally extricates the
rest of its body.

Dragon-flies are divided into three families, of which the first two have more
in common with one another than with the third. The Libellulidce are dis-
tinguished by their comparatively stout bodies ; by the size of their eyes, which
cover almost all the sides of the head, and very nearly meet on its crown ; and
by the structure of their lower lip, in which the median terminal piece is short
and slightly divided at the end, while the very broad palps spread out and overlap
it in front. The last character is useful in distinguishing the Libellulidce from the
next family, which in many respects they resemble. Their larvae breathe by
means of internal gills, and have a mask which is hollowed out on the inner side,
and somewhat resembles a helmet. Members of this family are found in most
parts of the world, and about twenty species occur in Europe. The jEschnidce
have eyes even larger than those of the Libellulidce. The end piece (ligula)

ORTHOPTERA. 169

of their lower lip is not divided in front, and not exceeded in length by the
palpi ; while each of the latter is armed with a strong tooth or spine. The
abdomen is long, narrow, and cylindrical. Their larvae are more elongate, and
have bigger eyes than those of the last family. The flat mask has the palpi narrow,
and armed with a movable hook at the tip. Like the larvae of the Libellulidce
they are provided with intestinal gills. Some of the largest dragon-flies belong to
this family.

The Agrioniclce form a family of slender - bodied dragon - flies, which have
both pairs of wings shaped nearly alike. They are further distinguished from the
other two families by the shape of the head, the smaller size of the eyes, and
the structure of the lower lip. The head has a projection at each side, at the
end of which is placed one of the two hemispherical eyes ; and on the wide space,
lying between the compound eyes, there are three ocelli arranged in a triangle.
The lower lip consists at its free end of three parts of nearly equal length ; the
median piece (ligula) being notched in the middle, while the two palpi consist of
two joints, of which the first is large and terminates in an inwardly curved spine,
whereas the second is small and articulated with the first, outside the base of its
spine. The larvae may be known by the three leaf-like tracheal gills at the end of
their body, which are wanting or inconspicuous in those of the other families. This
family contains many of the most brilliantly and variously coloured dragon-flies ;
the sexes of the same species often differing in coloration. Some of the exotic
species attain a great length, but this is brought about by the elongation of their
slender abdomen without a corresponding increase in the proportions of the other
parts of the body.

The day-flies, or May-flies (Ephemeridce), constituting the second
group of the Pseudoneuroptera, are comprised in a single family.
They have soft and fragile bodies, with a long ten-jointed abdomen, bearing at the
extremity two or three long, bristle-like, and many-jointed tails. The hind- wings
are sometimes wanting, and, when present, are always much smaller than the front
pair, the latter being usually three-sided, with the corners rounded oft'. Three
ocelli, in addition to the two large compound eyes, are borne upon the head ; and
the antennae are short, and composed of two stout basal joints, followed by a slender,
many-jointed bristle. In the adult the mouth-organs are never well developed,
but remain small and soft. The jaws have no function to perform, as the perfect
insects do not eat, but devote entirely to other pursuits the short span of life
remaining to them. The common notion that the life of the May-flies in the winged
state lasts but a single day is sometimes, but not generally, true, many being able
to live several days, provided the atmosphere be not too dry. There are some,
however, which do not live for even the proverbial day, but emerge one evening,
only to perish before the sun again appears. There is less truth in the supposition
that these insects appear only in May ; May-flies of one species or another being
seen on fine days throughout the summer and autumn. They are to be found in
the neighbourhood of rivers and lakes, some flying only by night, and others during
the cooler hours of sunlight, or on favourable evenings until a little after sunset.
During the heat of the day they seek repose, with their wings raised vertically.
If the day be cold and raw, they seldom fly, but remain under shelter. In fine

170

INSECTS.

MALE OF COMMON MAY - FLT,

Ephemera vulgata (nat. size).

weather, however, they may sometimes be seen assembled together in swarms
about sundown, and engaged in their pastimes, which are continued till some time
after sunset. The peculiar up-and-down movement, which marks the flight of
some species, has been often observed ; and the mazy dance of the May-flies has

been described by more than one author. In these
dancing assemblies the male insects always greatly
outnumber those of the other sex. The larvae of
the Ephemeridce live in water; a few kinds are
carnivorous, but most feed upon the minute vegeta-
tion scattered through the mud or covering stones,
and the larger aquatic plants. Many remain con-
cealed in the banks or under stones, while others
rove among water- weeds, and swim with celerity.
The larvae of some genera are found only in large
rivers. The eggs are, in some cases, deposited at the
surface of the water, and then sink to the bottom ;
but in others the female creeps into the water to
lay her eggs in patches on the under side of stones.
The eggs are exceedingly numerous, and vary in
shape according to the genus. The larvae cast their
skin several times ; they are at first without special
organs of respiration, but when they are about eight or ten days old tracheal gills
begin to appear and ultimately develop into forms, which vary somewhat in the
different genera. The gills are attached in pairs to the sides of some, or all, of the
first seven segments of the abdomen, in
some species standing out straight from
the sides, and in others turned over the
back. The mouth-organs of the larvae are
better developed than in the adult, the
mandibles being nearly always strong and
toothed, and sometimes giving off a tusk-
like process in front of the head. At their
transformation most May - flies do not
change directly from the larval form into
the imago, but first pass through a stage,
known as the subimago, in which they
have their wings expanded, and breathe
through the spiracles like the perfect
insect. In this form they are distin-
guished by the dulness of their integu-
ment, the shortness of the fore-legs and
tail-bristles, and the less prominent and a. may-fly at its final moult, with the imago

, ,, ™ , . p ESCAPING FEOM THE SKIN OF THE SUBIMAGO.

duller eyes. The subimago emerges from THE LARVA BEL0W=

the larval skin at the surface of the

water, and, after standing awhile upon the water, flies to a more convenient

resting-place. At the next moult, which soon follows, the perfect insect makes

ORTHOPTERA.

171

Stone-Flies.

its appearance. The emergence of May-flies takes place at different periods during
Bummer and autumn, and that of any one species may last for several days in
succession. At this time they sometimes appear in countless numbers, as thick
in the air as snowflakes, and at the end of their brief existence leave their dead
bodies to cover the ground, or float in masses down the stream.

Nearly fifty species of Ephemeridm are found in the British Islands. Two of
the commonest (Ephemera vulgata and E. danica) are, in the subimago stage,
known to anglers as "green drake," and "grey drake." They are four-winged
species, with a body from one-half to three-quarters of an inch in length, and
furnished at the end with three very long tails. The fore-legs are extremely long,
especially in the males, which sex is distinguished also by the much larger size of
its eyes. The larvae of E. vulgata burrow in the mud, or hide under stones, in
ponds and sluggish streams. They have rather long antennae, and the tusks of
their mandibles project a good way, and cross one another in front of the head.
They have six pairs of tracheal gills, which are turned up over the back, each gill
consisting of two narrow blades, united at the base, and fringed with hairs along
each side. The final transformations of the larvae occur about the end of May, or
early in June, at which time, on a fine evening, the winged insects may sometimes
be seen in hundreds, dancing in the air.

The stone-flies (Perlidm), forming the last group of Pseudoneur-
optera with aquatic larvae, are narrow, elongated insects of a flattened
form, with a good-sized head, rather
long, many-jointed antennae, and four
not very closely reticulated wings,
which shut horizontally over the body
when at rest. The abdomen usually
carries two long, multiarticulated
styles at the extremity. The mouth-
organs are weakly developed in the
adult insects ; the mandibles and
maxillae are membranous ; the maxil-
lary palpi long, with slender terminal
joints, and the labial palpi three-
jointed. The thorax is square or
oblong, with its three segments
almost equally developed. The tarsi
are three-jointed, and have their claws
separated by a bilobed pad. The
species of this family are not numer-
ous, though some are almost worldwide in their distribution. The adults appear
about the same time as dragon-flies and alder-flies, and frequent nearly the same
places. Though they have large enough wings, they fly heavily, and not for any
considerable distance at a stretch, and are generally most active in the evening.
The female fastens her eggs loosely together, and drops them in masses as she flies
over water. The larvae are mostly found in rapid streams, where they keep under
stones, or among broken pieces of wood, and live by preying actively upon the

common stone-fly {I'erla bicaudata).

1, Larva ; 2, The fly escaping from the larval skin ; 3, The
perfect insect.

1 72 INSECTS.

weaker creatures inhabiting the same waters. They have strongly developed jaws,
and rather long palpi. They breathe by means of tracheal gills, in the form of
tufts of filaments, attached to the bases of the legs and the sides of the integument
which joins the three thoracic and the first abdominal rings to one another. The
two filamentous tails may have a pair of tracheal tufts at their base. In later
stages of their life the larvae exhibit rudiments of wings. When the time for its
transformation arrives, the full-grown larva, or nymph, leaves the water by
climbing the stem of a plant, or crawling some distance up the bank until it finds
a dry stone on which to stand, when the emergence of the imago takes place in the
usual way, preceded first by a splitting of the larval skin along the middle of the
thorax. When the insect is free, its wings dry rapidly, and it is soon ready to fly.
A fact of importance, first noticed in the Perliche, though it also occurs in
some other groups, is that the tracheal gills are retained by the perfect insects,
where they are attached in the same places as in the larva, but much reduced in
size, and probably, in most cases, functionless. As an example of the Perlidce, one
of the best known British species, Perla bicaudata, is figured on p. 171.

Termites, or The termites, or white ants (Termitidce), differ considerably in

White Ants. one respect from all the other groups of Pseudoneuroptera. They
live in societies which are of a highly organised and complex nature and most
resemble those met with among insects of the highest type, such as bees and ants.
This is, however, the only direction in which the termites diverge to any extent
from the rest of the Orthoptera ; for, like all these, they pass from the larval to
the adult state by a series of gradual changes ; while, in the structure of their
bodies, they show an affinity with some of the lowest groups of the order. In the
termites the head is free and distinct, with the antennae composed of a number of
small bead-like joints, and rather short. The perfect insects have compound eyes,
and, as a rule, two ocelli ; but the wingless individuals are generally without eyes
of any kind. The mouth-parts, which are constructed on a clearly orthopterous
plan, are not very unlike those of a cockroach, and consist of a distinct upper lip
(labrum), two strong horny mandibles, a pair of two-lobed maxillae with five-
jointed palpi, and a lower lip (labium), divided at the end into four lobes, and
bearing three-jointed palpi. In the thorax the first segment is well developed, and
its dorsal plate, or pronotum, is rather broad and flat; the other two segments being
less strongly developed, though in the winged insects attaining a fair size. Both
pairs of wings are much alike ; they are long, narrow, not very closely veined, each
wing being marked by a transverse suture at a short distance from the base ; and in
a state of rest they are laid flat over the back. The legs are slender, and well fitted
for running, and their tarsi are four-jointed. The abdomen has a slightly elongated
or oval form, and carries two very short appendages — the cerci — near its extremity.
The common habitation of a society of white ants is known as a nest ; and in
each nest, which is divided into a number of cells or chambers communicating with
one another, there may be found several different kinds of individuals in addition
to the larvae. Some are provided with wings, or with the rudiments thereof, and
are distinguished also by having eyes. These are the sexually developed males
and females, which are capable of reproducing their kind ; though this function is,
as a rule, carried on by a single couple in each nest. The king and queen — as this

ORTHOPTERA.

*73

couple are named — are lodged in a large cell near the middle of the nest, and may
be recognised by their large size, and the fact that they retain but small stumps of
the wings which they once possessed. The royal cell is larger than the others, and
has thicker walls ; while the passages leading into it are too small to afford the
occupants a means of escape, though large enough to admit the workers, which
come and go, some to bring food to the royal pair, others to carry away the eggs
laid by the queen. At this time the abdomen of the queen, owing to the number
of eggs it contains, is swollen to an enormous size. "She lies there," writes
Drummond, in reference to one of the African species, "a large, loathsome,

WHITE ANTS AND THEIR DEVELOPMENT.

1, Male of Termes dirus ; 2, The same, seen from the side ; 3, The head, enlarged ; 4, Worker ; 5, The same, front
view ; 6, 7, Soldier, side and front view ; 8, Worker (much enlarged ); 9, Nymph ; 10, Queen.

cylindrical package, 2 or 3 inches long, in shape like a sausage, and as white as a
bolster." Her eggs are discharged at a rapid rate, amounting in a single day to
several thousands, and the process is continued with the same activity for months
in succession. Both workers and soldiers are wingless members of the community,
and, in the majority of species, have no eyes. The workers have small and
rounded heads, with short mandibles, and well-developed maxillse and palpi;
whereas the soldiers are easily recognised by their big, square, or oblong heads,
and long mandibles. The workers are the most numerous class, and have many
duties to perform in the way of building, tunnelling, and providing food for the
young larvae and for the king and queen. The soldiers look after the protection
of the workers, and act generally in defence of the community. In one genus

1 74 INSECTS.

there are no true mandibulate soldiers; but there is instead a class of individuals,
known as " nasuti," from the fact that their pear-shaped heads are prolonged in
front in the form of a beak The exact part which the nasuti play is not
yet clearly known ; but, like the soldiers of other species, these individuals
appear at the first sign of danger, and shake their head and palpi in a most
menacing way. The eggs of the queen termite are, as mentioned, carried away
by bodies of workers, and placed in special chambers, or nurseries. When the
young larvae are hatched, they are at first indistinguishable from one another,
and are little blind creatures,, with soft and pale integument ; and it is only after
the first or second moult, that they begin to show those differences which subse-
quently distinguish the larvae of the various classes. They are fed with a special
kind of food, consisting of comminuted dead wood, mixed with saliva, which certain
of the workers prepare for them. By varying the quantity and quality of the
food supplied, the termites appear able to arrest or deviate the development of
larvae that would, in the ordinary course, become perfect insects or, in other words,
they can produce workers and soldiers from larvae which, if fed upon a different
diet, might develop into winged insects fitted to become kings and queens. And
it has been shown that neither the soldiers nor the workers of the termites belong-
to one particular sex only, as is the case with the neuters of bees and ants, but
that individuals of both sexes, in an imperfect sexual condition are comprised in
each class. The winged insects into which many of the larvae develop are most
abundant at certain periods of the year, especially after rains ; they do not remain
long in the nest, but, after a few days at the most, make their way out, or are led
out by the workers, and shortly afterwards take flight. They may often be seen
flying in swarms, and at night sometimes enter houses, being attracted by the
light. Many are devoured by birds, which seize them as they leave the nest.
When they have finished their flight, and alight on the ground, they shed their
wings, which easily snap off at the line of suture near the base. If a couple,
chancing to be near a termite burrow, are found by some workers, they are brought
in, a royal cell is prepared for them, and, as king and queen, they become the
parents of a new colony. Some larvae develop into individuals, which, although
fitted to perform the functions of perfect insects, never possess complete wings,
but are provided at most with wing-pads, or rudiments of wings. These indi-
viduals, which somewhat resemble the nymphs of the perfect insects, are known as
substitution kings and queens, and take the place of true royal couples, when from
any cause the latter are not to be found.

The food of white ants consists ordinarily of decaying wood, or similar
vegetable matter, which, when it has passed in a half -digested state through their
bodies, is eaten again. These insects have also the habit of devouring their dead,
which makes it possible to destroy a whole colony by placing a little arsenic or
mercuric chloride in their food ; for the few that die through first partaking of the
poison are eaten by others, which in their turn are also devoured, and so
the poison is spread through the entire population. About two hundred species
of termites have been described ; and these inhabit chiefly the tropical and sub-
tropical parts of the world, although two small species are found in the south of
Europe. Some species live in the hollows they have eaten out in the interior of the

ORTHOPTERA.

'75

trunks and branches of trees, or in timber. They line the galleries they make, which
are often so close together as to be separated only by a thin wall, the wood in the
interior being almost all eaten away. A few make openings to the exterior, and form
nests around the branches of trees ; these nests being sometimes as large as a sugar-
barrel, though the size varies considerably. The nests of most species are usually
placed entirely below the level of the ground, and often lie beneath mounds of
earth raised above the surface. Some of the larger African species, such as Termes
bellicosus, build mounds of earth, frequently reaching a height of 12 or 14 feet.
These mounds, which may stand singly, or in groups of varying size, are divided
inside into chambers and galleries communicating with one another and with the
nests and galleries underground. The nests of this kind, which consist almost
entirely of clay, become in time quite hard and solid, and are much more
durable than those which are composed of particles of dead wood pasted
together with sticky saliva or with excrementitious matter. From the central
nests termites construct underground galleries or tunnels leading in different
directions, and sometimes reaching hundreds of feet in length. When it is
necessary for the workers to go above ground in search of food, they protect
themselves by building covered ways leading to the object they desire. Their
tunnels sometimes lead to the interior of houses, and when once termites gain
admittance in this way there is scarcely any limit to the mischief which may
result from their operations. The wooden pillars that support the roof, the wood-
work of the roof itself, and even articles of furniture, may be destroyed before
the inhabitants become aware of what is taking place. For in tunnelling through
wood termites take care to leave the outer shell intact ; and what appears on the
outside to be a solid piece of wood may consist in the interior of nothing but a
series of galleries lined with white-ant mortar. These insects easily make their
way into wooden boxes, and quickly destroy the books, papers, clothing, or what-
ever else they may contain. The rapidity with which they work is remarkable,
and in a single night they have been known to burrow up through the leg of a table,
then across the table, stopping on the way to devour the articles lying on it, and
down through another leg into the floor again. Forest trees, also, are often ruined
by the action of termites, which, in order to get at the dead branches will some-
times bore their way up through the trunk, and thus bring about its premature
decay.

The book-lice and the other insects classed with them in the
family Psocidce form another small group of Pseudoneuroptera.
They are mostly very small insects, with a proportionately big head, swollen in
front, and carrying prominent eyes, three ocelli, and bristle-like antennae. Their
mandibles are horny at the tip, but the other parts of the mouth are usually soft
and membranous; the maxillae being bilobed, with four-jointed palpi, and the
palps of the bifid labium rudimentary. The middle segment of the thorax is
the largest, and the prothorax is usually very short and narrow. The wings,
which are wanting in some species, are slanting in repose, like the sides of a roof,
and cover over the abdomen ; they are of an almost glassy transparency, and have,
as a rule, an open system of neuration. The tarsi are composed of two or three
joints. Most species of Psocidce live in the open air, and feed on fungi, lichens,

176 INSECTS.

and the fragments of other plants ; the largest European species (Psocus lineatus)

being scarcely more than a quarter of an inch long.

The Mallophaga, commonly known as bird-lice, are small wingless
insects, resembling ordinary lice to some extent, but differing from them

in many characters, and especially in the structure of the mouth, which is fitted

for taking food by biting instead of sucking. They form a distinct group, now

generally placed in the Pseudoneuroptera, though
some entomologists assign it a position near the
Pediculina or true lice. The bird-lice are flat-
bodied insects, with a broad head, varying a good
deal in form, and a thorax which usually appears
to consist of only two segments. Their antennae
are short and composed of three, four, or five
joints ; and their eyes, when present, are simple.
The mandibles appear as short hooks, sometimes

Psocus lineatus (enlarged three times). t0°thed °n the iimer skle ' the maxin* are short

and said to be always palpless ; while the lower
lip is distinct and often bears palpi. The legs are short and stout, and have
two-jointed tarsi, each of which carries at the end either one or two claws. As
bird-lice are found on mammals as well as on birds, their name is to some extent
misleading.

True Orthoptera (Orthojrtera Genuina).

The insects of this suborder differ chiefly from those of the last group in the
characters of their wings, in which the two pairs are not formed alike. The fore-
wings, which are usually stiff and tough, and in some cases horny, serve as wing-
covers, and are generally spoken of as elytra ; whereas the hind -pair are
membranous, and capable of being folded longitudinally, or both longitudinally
and transversely. The division of the ligula, or terminal piece of the lower lip
into two or four lobes, is usually more complete than in the Pseudoneuroptera.
It is usual to divide the true Orthoptera into two series or tribes — the Saltatoria,
with strongly-developed hind-legs, adapted for leaping, and the Cursoria, in which
the hind-legs are not thus developed, but are better fitted for use in running and
walking. The saltatoria, or jumpers, are sometimes spoken of as the Musical
Orthoptera, since nearly all these insects, such as crickets, grasshoppers and locusts,
are noted for the loud chirping sounds which the males produce. The females are
supposed to be attracted by the chirping of the males; they seldom emit any
sound themselves, and when they do it is generally of a very feeble character.
It is probable that most insects can hear, but by what means they do so is, in the
majority of cases, to a great extent a matter of conjecture. The Saltatorial
Orthoptera are, however, remarkable in possessing very definite organs of hearing,
which, though occupying a different position, are functionally comparable to the
ears of higher animals.

The crickets (Gryllidce) which form the first family of the sub-
Crickets. 1 ...

order, have a somewhat rounded head, supporting long whip-like

antennae. Their mandibles are strong and toothed ; the inner lobe of the maxillae

ORTHOPTERA

ORTHOPTERA.

177

being devoid of teeth, and the outer one long and slender. The fore-wings, or
elytra, do not differ from one another in structure, and, when at rest, are closely
applied to the somewhat thick and massive hind-body. The hind-wings are folded
many times, and may generally be seen projecting beyond the tips of the elytra.
The hind-legs are generally used in jumping, while the other two pairs are better
adapted for walking, although in the mole-crickets the fore-legs are thickened
and otherwise modified for use in burrowing. The tarsi of all the legs are com-
posed of either two or three joints. The abdomen bears near the tip two flexible,
velvety appendages, which are sometimes very long ; and in the females it usually
carries also a long exserted ovipositor. The chirping of crickets is produced by
rubbing the base of one elytron over the other; in which respect these insects
differ from most grasshoppers and locusts, and resemble only those grasshoppers
with long antennae, which belong to the family Locustidce. They resemble the
latter also in having their organs of hearing placed on the fore-legs. These organs
are lodged in the upper part of the tibiae, a little below their articulation with the

1-4, field-cricket (Gryllus campestris) — (1) male, (2) female, (3 and 4) young and old larvae ; 5, MALE OF the

house-cricket (Gryllus domesticus).

femora, and consist externally of two small depressions or pits on opposite sides of
each tibia, with a thin membrane stretched across the bottom of each depression.
Inside the leg a tracheal vessel widens out between the two tympanic membranes,
to form a vesicular expansion, on which are distributed the end cells and rods of a
nerve which comes from the first thoracic ganglion. Crickets are found all over the
world, but only four species are British. Of these one {Nemobius sylvestris) may
be recognised by its small size, being little more than a third of an inch long. It
is usually found among the dead leaves in woods, and appears to be restricted in
its range to the southern counties. The field-cricket (Gryllus campestris), which
sometimes measures an inch in length, is generally of a black colour, and lives in
dry fields, where it is often heard though seldom seen on account of its retiring-
habits. The house-cricket (G. domesticus) has a reddish brown colour, and
is somewhat smaller than the field-cricket. It has well-developed wings, and
the female has a long ovipositor. The mole-crickets, of which there is one
British species (Gryllotalpa vulgaris), have such a peculiar structure that
they are easily distinguished from all other insects. They have a long, smooth,
shiny prothorax ; rather short, close-fitting elytra ; and under-wings which, when
vol. vi. — 12

i78

INSECTS. )

rolled up, look like a tail curving down over the tip of the abdomen. The
abdomen itself carries two long; flexible tails, which are said to be used like
antennae, when the insect runs backwards. It is, however, by the extraordinary
shape of the fore-legs that these insects may be most easily recognised. These
limbs are thicker, but shorter than the hind-legs ; they have very short tibiae, each
ending below in four strong claws spread out like the fingers of a hand.

mole-cricket, with eggs and larvae (slightly enlarged).

Long-Homed Although named Locustidce, this family does not comprise the

Grasshoppers, locusts, but includes only those grasshoppers in which the antennae
are long and tapering, and the tarsi are four-jointed ; while the female is provided
with a long ovipositor. Besides these characters, there are some others which help
to distinguish the Locustidce from the members of the next family. In the present
group the organs of hearing are placed, as in the crickets, in the tibiae of the fore-
legs ; and the chirping of the male is produced by the friction of the wing-covers
over one another. The wing-covers, instead of being both alike, as in crickets,
exhibit a certain amount of difference in the arrangement of the veins and struc-
ture of the membrane in their basal part. Taking the male of the large British
green grasshopper as an example, it will be seen that on the portion of the right
elytron which folds horizontally over the trunk, there is near the base a somewhat
irregularly circular area, which has a glistening appearance, like a piece of talc.
This area is bordered by a strong prominent vein. In a corresponding position on
the left elytron, which, when closed, overlaps the right, there are also some thick
transverse veins, but the cells enclosed by these veins have a similar texture to
the rest of the membrane. When the insect rubs its left elytron rapidly over the
right the veins projecting on the under side scrape on the margin of the mirror, and
set the latter in vibration, thus giving rise to the well-known sound. The chirp-
ing of the Locustidce is generally louder and more prolonged than in the other
grasshoppers. In certain North American species known as katy-dids, the song
seems to consist of these words repeated again and again, with a slight variation.
The life-history of the Locustidce, so far as it is known, does not differ in any
essential respect from that of the Acridiidce. It is probable that in most cases the

ORTHOPTERA.

179

female uses her long ovipositor to lay her eggs at some depth in the ground, though
in some species the female is known to deposit her eggs on plants. These grass-
hoppers are less herbivorous in their habits than those belonging to the next family ;
many of them are, in fact, believed to be more carnivorous than herbivorous in
their tastes. The Locustidce are most numerous in species in America and Asia ;
there being not many more than two hundred species in Europe, of which about
ten are British. In the large green grasshopper (Locusta viridissima), which is
nearly an inch and a half long, and is easily distinguished by its size from all the
other British species, the male makes a harsh and strident noise, by which atten-
tion is attracted, when otherwise, owing to its green colour, it might altogether
escape notice. Green is the prevailing tint in very many species of this family.
In some species the elytra have the most exquisite resemblance in colour and
venation to green leaves; while in others they look more like withered leaves.
Nowhere is this style of protective coloration better displayed than in the exotic
genera Cycloptera and Pterochroza, one of the species of which is figured in the

1, female of Hetrodes spinulosus ; 2, male and female of Meconema varium. (All nat. size.)

coloured Plate. The shape, colour, and venation of the wings are not only exactly
like those of leaves, but there may be seen, here and there, little glistening, trans-
parent patches of cuticle, which reveal, as it were, the work of an insect grub.
In others, fungi seem to grow on the leaves, and leave their mark in the dis-
coloured patches which may be seen scattered about. Amongst the species of the
family remarkable in other respects we have space to mention only a few. In
the genus Hetrodes the adult insects of both sexes are without wings ; the pro-
thorax is very large, and is armed above with a number of spines. An idea of the
general appearance of the adult insect may be gathered from the figure of Hetrodes
spinulosus. This species is found in Arabia and Syria. For the sake of contrast
the male and female of a small British grasshopper {Meconema varium) are figured
beside it. The latter is winged in both sexes ; it is found in oak trees, and belongs
to a subfamily which is peculiar from the fact that the elytra of the male have no
stridulating organs.

The locusts and short-horned grasshoppers (Acridiidm) are dis-
tinguished by easily recognised characters from the other two families
cf the suborder. The antennae are short, seldom attaining more than half the

180 . INSECTS.

length of the body, the tarsi are three-jointed, and the female always has a very
short ovipositor. They differ also in the position of the auditory organs, and in
the mode by which the males produce the chirping. In these insects the organs of
hearing appear externally as two pits, somewhat crescentic or semilunar in shape,
placed one on each side of the first abdominal segment, immediately behind the
thorax. At the bottom of each pit there is a tense membrane, which on its inner
side is brought into relation with the terminal rods and fibres of a nerve which
arises from the last thoracic ganglion. It was thought that these pits were in some
way concerned in the production of sound, but it is evident from their structure
that this is not the case, while they really seem capable of serving no other function
than that of ears. Moreover, it is now known that the chirping of these insects is
produced by rubbing the hind-legs up and down against some of the projecting
nervures in the sides of the closed elytra. When the insect is stridulating it keeps
the tibia of the leg folded up against the femur. In some species the sound is
heard at both the upward and downward stroke of the legs, in others at the
downward stroke only. The sound varies in intensity in different species, and for
this reason some of the commoner species may be recognised even before they are
seen. In most of these insects the front of the head is vertical, or slightly inclined
backwards, but in some (Tryxalince) it is much inclined backwards, and the whole
head seems prolonged in a way that makes it look like a cone or wedge, with the
antennas and eyes near the apex, and the mouth placed below under its base. The
Acridiidce are usually provided with three ocelli in addition to the compound eyes,
the ocelli being as a rule more distinct than in the Locustidce. The mouth-organs
are well developed, consisting of a large upper lip ; strong, toothed masticatory
jaws ; five-jointed maxillary palpi ; and a lower lip, divided at the end into two or
four lobes, and bearing three-jointed palpi. The prothorax is generally large,
much longer above than below, and often carrying a prominent crest along the
middle. Wings are usually present, but the hind-pair are wanting in the females,
or even in both sexes, of some species. In their general life-history the Acridiidce
are probably much alike. The female lays her eggs at a short depth below the
surface of the ground, or attaches them to the stalks of grasses, and usually
surrounds them, in mass, with some sort of protective covering. Later on in the
same year, or in the spring of the year following, the larvse are excluded. They
soon become active, and — except that they are without wings, have shorter antennse,
and are of smaller size and no definite colour — do not differ much in appearance
from the perfect insects. After undergoing, as a rule, about six moults, the larvae
which are hatched in the spring become adult late in the summer. It is generally
in the days immediately following their entry into the perfect state that the male
insects are loudest and most persistent in their song. Few of the British Acridiidce,
of which there are about a dozen, are remarkable for the brightness of their colours ;
nor do any cause trouble by a great excess of numbers. But amongst the exotic
species there are many exhibiting vivid tints of colour ; and some which are
capable of multiplying to such an extent as to become a serious source of mischief
in the places where they abound. It is to the species accustomed to assemble
together, and migrate from place to place, in vast swarms, that the name of locusts
is more especially applied ; this habit really constituting almost the only difference

ORTHOPTEKA.

between the locusts and many of the other grasshoppers of this family. Grass-
hoppers feed chiefly on the grasses of different kinds, including most of the
cultivated grains ; but locusts leave scarcely anything in the nature of vegetation
untouched, when, as often happens, they invade a district where the ordinary
herbs and grasses are insufficient to support their vast numbers. Trees and shrubs
are then stripped bare of their leaves, and the bark and wood even are not spared.
Pressed by hunger, locusts do not refrain from attacking plants which at ordinary
times they seem to avoid. They frequently devour their own dead, and even
carry their cannibalism so far as to kill and eat the newly-moulted and soft-
skinned larvae. Different species of these destructive insects are found in all
the great regions of the world ; though North Africa is, perhaps, the one which

migratory LOCUST OP SOUTH-EAST Europe {Pachytylus migralorius) and its LARViE (nat. size).

suffers most from their ravages. The locusts referred to in Scripture belonged in
all probability for the most part to the species known as Schistocerca peregrina,
which has its chief home in the Sahara and surrounding districts.

Several other species are found in North Africa, and in South Africa Pachy-
tylus migratorioides is one of the most widely distributed. Great swarms of
locusts of this species have been seen at different times in recent years ; one which
passed over Pretoria in 1891 was estimated to be twenty -five miles long, one and
a half broad, and half a mile in depth. It was probably to this species also those
locusts belonged, of which Barrow, giving an account of their ravages in the year
1797, states that the whole surface of the ground over an area of about two thou-
sand square miles was literally covered with them ; and that when driven into the
sea by a north-west wind, they formed a bank on the shore three or four feet high
and fifty miles long. Amongst European locusts, the best known is P. migratorius,

l82

INSECTS.

Tettix subulata (nat. size).

which occurs chiefly in the south-east, and is found also in Egypt and in West and
Central Asia.

Passing from the locusts, we may briefly notice a few of the other insects of
the family. The Tryxalince are remarkable on account of the peculiar shape of

their head, to which we have already
alluded. No species of this sub-
family is found in Britain. In the
allied Tettigince the pronotum is
produced behind into a long process,
which in some of the species reaches
beyond the tip of the abdomen. Two
of the smallest species of grass-
hoppers found in Great Britain belong
to the genus Tettix — the typical
genus of this subfamily. The genus
Pnewmora, which is represented only
in South Africa, is characterised by
the bladder -like dilatation of the
abdomen in one of the sexes. The hind-legs in this genus are rather short, and
are scarcely adapted for leaping.

stick- and Leaf- The stick- and leaf-insects (PJiasmatidce) are chiefly interesting

insects. on account of their resemblance to the objects after which they are
named. They form one of the families of Cursorial Orthoptera, and, in addition
to the easily recognised shape of their bodies, are distinguished by the following
characters. The head is distinctly visible from above, and is set somewhat
obliquely, with the mouth placed well forwards on the under side. The short
prothorax is much shorter, as a rule, than the next segment, or mesothorax. The
legs which, in shape, usually harmonise with the shape of the body, are inserted
somewhat close to the sides of the thorax, those of each pair being separated from
one another by a rather broad sternal plate ; the tarsi are five-jointed, and exhibit
a pad-like lobe between the claws of the terminal joint. In the stick-insects the
trunk is long, narrow, and cylindrical ; the legs are generally long, and, when
stretched out unsymmetrically from the body, as they habitually are in the resting
insect, look like smaller branches coming off" from a thicker, jointed stem. Many
stick-insects have no wings at any stage of their life, and it is difficult, in such
cases, to distinguish the adult insects from some of the older larvae. In the winged
species the fore-wings are usually very short, and often cover only a small part of
the hind-pair; the latter exhibit a division into two distinct areas — one more
membranous and transparent, and often brightly coloured ; the other, which is
narrower, and placed next the anterior border, being coloured like the elytra.
When the wings are at rest, the brightly-coloured portion is folded beneath the
other part, which alone is then exposed to view, so that there is nothing to detract
from the general stick-like appearance of the body. These insects are usually found
amongst underwood, or on shrubs and the stems of long grasses. They are mostly
inactive during the day, and are not easily seen owing to the way in which their
form and colours harmonise with their surroundings. They roam about at night,

ORTHOPTERA.

183

and feed upon leaves. Most inhabit tropical and subtropical countries, and
amongst them are some of the largest insects known, more than one measuring
over 13 inches in length. Two species are found in South Europe, belonging to
the genus Bacillus, and are both wingless forms of rather small size. One of these
is figured in the illustration ; and, as examples of some of the more finely-coloured
tropical forms, two species from the island of Borneo are represented on the
coloured Plate of Orthoptera.

The leaf-insects, though belonging to the same family, exhibit a marked
contrast to stick-insects in the shape of the body, which, instead of being narrow
and cylindrical, is broad and flat. The male is narrower than the female, and
distinguished also by having moderately long antennae, well-developed hind- wings,
and short fore-wings. In the female the antennas are very short, the hind-wings

one of the stick-insects of south Europe (Bacillus rossi) and its larva (nat. size).

are rudimentary; and the elytra are fairly large, leaf-like structures, which, in
some species, almost entirely cover the broad, flattened abdomen. The legs have
broad, leaf-like expansions on both the femora and tibiae, contributing to the
general leaf -like appearance. It is remarkable that the colour of these insects,
which is either the green of a living leaf, or some shade of yellow or brown, like
that of a withered leaf, is due to a substance similar in its nature to chlorophyll,
or the green colouring matter of plants ; and it is stated that the internal structure
of the elytra bears a striking resemblance to that of a plant. All these curious
insects belong to the single genus Phylliu7n, and are found in the Oriental countries,
and in some islands of the Indian Ocean.

The praying insects, or Mantidce, constituting the next family
of the suborder, have the head turned down, with the face inclined
backwards, so that the vertex projects in front, while the mouth lies close to the
lower edge of the prothorax. They have many-jointed, bristle-like, or comb-like
antennae. The prothorax is generally much longer than the other two segments
of the thorax taken together ; whereas the two hinder pairs of legs are long, and
resemble one another. The fore-legs — which are inserted close to the front and
wider end of the prothorax — exhibit a peculiar form and structure, their coxae
being long and three-cornered, and often spined on the angles, and the femora broad,
flattened, and grooved below to receive the tibiae, which can be folded back upon

Praying Insects.

i84

INSECTS.

them like the blade of a knife. The tarsi of all the legs are five-jointed. These
insects usually have two pairs of wings, of which the fore-wings, or elytra, are
ordinarily of the length of the abdomen. The characteristic posture which these
insects assume when resting on a tree or shrub with their prothorax raised, and
the fore-legs doubled up in front of them, accounts for their common names of
soothsayers and praying insects. They are amongst the most predaceous and
bloodthirsty of creatures, living on flies and other insects, which they seize with
their raptorial fore-legs, in the manner shown in the illustration. Mantidce
are chiefly found in tli3 warmer parts of the world, but a few species occur
in South Europe. The best known of these is the figured Mantis religiosa.
Some species, such as the African Harpax ocellata, shown on the coloured

Cockroaches.

PRAYING INSECT SEIZING A PLY.

The egg-case and some of the escaping larvse are shown at the left-hand side of the figure.

Plate, are curiously marked, while others are prettily coloured. The colours are
sometimes so disposed that the insect in its resting attitude resembles a flower,
and thus draws towards it other insects, which, when they have approached near
enough, are suddenly caught, as if in a trap, by the arms of the deceiver.

The cockroaches (Blattidce) constitute one of those families in
which the legs are more specially fitted for running. They have a
rather short head, with a large, flat face, looking slightly downwards, and the
mouth brought close to the prosternum. The eyes are large and compound, and
in the place usually occupied by the lateral ocelli there are often to be seen
two pale soft spots in the integument. The long and tapering antennae are
inserted close to the eyes, and composed of a stouter basal joint, followed by a
number of short joints. The strong and horny jaws are toothed or spined on the
inner side, and thus well adapted to biting ; and the head is scarcely visible from
above, being overlapped by the large, shield-like plate of the prothorax. The legs
are long, with spiny tibiae, and end in five-jointed tarsi. The pulvillus, which pro-
jects between the tarsal claws of these and many other insects, constitutes a sixth
joint, although not usually reckoned as such. Cockroaches are generally provided
with two pairs of wings, the front pair being stiff and horny, while the hind pair

ORTHOPTERA.

185

are of a more membranous texture, and, in a state of rest, are folded longitudinally,
and almost entirely covered by the elytra. The abdomen is broad and flat, and
carries two jointed appendages — the cerci — near its extremity. About six
species are found in Britain, of which three only are really indigenous, the
others having been imported. The common cockroach (Periplaneta orientalis)
is believed to have belonged originally to the East, though now found in almost

egg-case of the common kitchen cockroach (the top figure nat. size, the others much enlarged).

all parts of the world. These insects are commonly spoken of as " black-beetles,"
though not beetles, and not black, but having a reddish brown colour. The male is
easily recognised by the wings, of which there are two pairs, scarcely reaching
beyond the middle of the abdomen. The female is broader in the body, and has
very short rudimentary fore-wings and no hind-wings. Her eggs are arranged in
a horny case, opening at the top, and shaped like a purse, which she carries about
with her for some time, protruding from the end of her abdomen. She finally
deposits the egg-capsule in a crevice in the walls or below the floor, and after some
interval the young larvae are excluded. During growth they shed their skin several
times. The new skin is at first soft and of a pale or nearly white colour, but

1 2

cockroaches.
1, Phyllodromia germanica, male and female ; 2, Ectobia lapponica. (Nat. size.)

gradually hardens and gets darker. The American cockroach (P. americana)
which is such a pest on many ships, and is found about the docks and ware-
houses of seaport towns, is larger than the common species. Although it
somewhat resembles the latter in general colour, it has two pale bands on the
prothorax, and is winged in both sexes. The German cockroach (Phyllodromia

i86

INSECTS.

germanica) is another imported species, said to have first arrived with the soldiers
returning from the Crimean War, but now plentiful in some houses, especially in
bakeries and restaurants. It may be distinguished by its smaller size, and pale
yellow-brown colour, with two dark brown bands along the pronotum. Both sexes

Earwigs.

1, MALE OF THE LARGE EARWIG ; 2, THE COMMON EARWIG, WITH
AN ENLARGED FIGURE OF THE FLYING INSECT.

have wings. In some parts of Central Europe they live in woods, resembling in
this respect many other species, including three, belonging to the genus Ectobia,
found in woods in England. One of the latter (E. lapponica) enters houses in
some parts of Europe.

The earwigs (Farfimdidce), which form the last family of
Cursorial Orthoptera, possess distinct characters, and are sometimes
treated as a separate order, under the name of Dermaptera. Easily recognised by
the narrow body, short, squarely cut horny elytra, and the pincer-like appendages
of their abdomen, these insects are further distinguished by the intricate folding

of the hind - wings. The
elytra, or fore -wings, do not
overlap one another as in
most Orthoptera, but, like
those of beetles, simply meet
by their edges along the
middle line. The hind-wings,
which are thin and mem-
branous throughout most of
their extent, are folded, partly
like a fan, by means of folds
radiating from near the middle
of the anterior margin, and
also transversely. In this way they occupy a small space, and are almost com-
pletely covered by the elytra, a tiny piece only being left projecting behind.
When fully expanded, each wing is somewhat elliptic in outline, with a straighter
anterior and more rounded posterior margin. To these characters it is only
necessary to add that the tarsi are three-jointed, and the ligula of the lower lip
is deeply divided, to form two long lobes. This family is represented in almost
all parts of the world, but not more than two or three species are commonly
met with in Britain. The species are distinguished chiefly by the size and
shape of their forceps, the length and number of joints of the antennae, the
state of development of the wings (which in some species are altogether
wanting), the length and shape of the tarsal joints, and other characters.
The common earwig (Forficula auricular •ia), found all over Europe, is the best
known species. The female is usually smaller than the male, and her forceps
are shorter, and without teeth at the base. Her eggs are laid under stones,
moss, or in other such places ; and she watches over them with care. It was
long ago observed that the female earwig sits over her eggs, like a hen in a
nest, and if they happen to get scattered, gathers them all together again. The
young larvae when hatched keep close to her, clustering under her body, and
sometimes climbing on to her back. They are not very unlike their mother in
appearance, but are without wings, and of much smaller size. The large earwig

RHYNCHOTA. 187

(Labidura riparia), found somewhat rarely in England along the south coast,
is nearly twice the size of the common species, and its forceps has a large tooth
beyond the middle of its length.

Order Rhynchota.

The numerous insects included in this order exhibit great differences in their
external form, and while some, such as the Flatince, rival the butterflies and moths
in the beauty and delicacy of their colours, others are amongst the most loath-
some of creatures. But whatever be their form or colour, all agree in two
essential characters, the first consisting in the fact that their development takes
place without a complete metamorphosis ; and the second that all have the
mouth taking the form of a beak, or rostrum, adapted for piercing and sucking.
The beak consists chiefly of the lower lip (labium), which is long and narrow,
composed of three or four joints, and grooved along the whole length of its upper
or anterior surface. This groove forms a sort of sheath, in which are lodged four
long slender blades, corresponding to the mandibles and maxillae of other insects,
but here transformed into piercing organs. All these parts are covered at the
base in front by the narrow and slightly elongated upper lip (labrum). From
the structure of their mouth, which is fitted only for the reception of liquid nutri-
ment, it is easy to infer that these insects live by piercing tissues of plants and
animals, and extracting the juices. The larvae differ little from the adults except
in size, the absence of wings, and their usually shorter and more slender antennae.
In many, however, the females are without wings at all stages ; and in some
cases both sexes are thus unprovided. When wings are present, they may be all
of similar texture, or the front-pair may be somewhat stiffer and less membranous
than the hinder. Wings of both these kinds are found in the section Homoptera.
In other cases, while the hind-wings are entirely membranous, the front-pair are
stiff and horny for some distance from their base, and thin and membranous
towards their extremities. Such wings, which characterise the section Heterop-
tera, are known as hemi-elytra. Over eighteen thousand species are already
known. Fossil remains of the order are found, in strata of the Jurassic epoch,
and are tolerably abundant in amber and other beds of Tertiary age.

All the Heteroptera, no matter how different they may be in external form
or mode of life, are termed bugs, although this name was originally applied only
to the bed-bug and a few closely-allied species. Most are winged insects, in
which the fore-wings known as hemi-elytra, or simply as elytra, always have
the form described above. Their antennae are either short and inconspicuous,
as in the water-bugs, or distinctly visible as in the land-bugs, and are generally
composed of a small number of joints. As a rule they have two compound eyes,
and often two or three ocelli. The first segment of the thorax is usually large,
with the head sunk deeply into it. The abdomen generally has an oval flattened
form, and the legs are mostly slender. With few exceptions bugs are characterised
by a peculiar and somewhat unpleasant odour, which arises from a liquid secreted
by special glands placed in the front part of the abdomen, and opening to the
exterior by means of two small ostioles on the ventral surface of the metathorax.

i&8 INSECTS, -

Bugs are divided into two tribes, based upon their mode of exist-
Land-Bugs. to . . r

ence, and the fact that in one tribe — the land-bugs, or Geocorisa —

the antennae project, and are distinctly visible, while in the other — the water-
bugs, or Hydrocorisa — they are very short, and hidden below the eyes. The shield-
bugs (Pentatomatidae), which constitute one of the largest families of the Geocorisa,
are so called on account of their large scutellum, which reaches at least to the
middle of the abdomen, and sometimes quite to its extremity, covering it over
completely. The fore-wings are sometimes chitinised only near the basal margin,
especially in those species with a very large scutellum. The body has in general
an elliptical outline, or is shaped like a scutcheon, owing to the projecting lateral
angles of the somewhat hexagonal pronotum. These bugs are mostly found on low
plants, some in concealment, many showing themselves openly, and often attracting
observation by their striking colours. The adults pass the winter sheltered under
bark or dried leaves. In early spring the females lay their eggs on the foliage of
low plants, shrubs, and pine trees. The oval or spherical eggs are provided with
an operculum, or lid, and disposed in patches resembling honeycomb. The

larvae moult several times in the course of their
^^^^^^^^^^rt|^«^v growth, and thus gradually effect a change in

r^i A( A t^ — ^ their form and coloration. They feed on the

Jji^^U^^^'^S^y^m^ juices of plants, or, in some cases, of animals, and

^H^^BS^^^n^m UK?" attain their ('nil size towards the end of summer.

YtK^JI |5i$rtift?tP^# r','u' European species are rather limited in number;
^/^h^H ^T^^F^Mi^^y but many forms arc found in other parts of the

^o^P^^A^^^^rJ^^ world. The Hottentot bug (Eurygaster maurus)

^^^^tS^Se^y/v tficAl(\//1r *s the name given to a species with a very large
^Hj^^^j^^/^fc^M^^^v"* scutellum, found throughout nearly all Europe.
hottentot bug (nat. size). It is of a yellow, dark brown, or black colour,

with two clear spots on each side of the base of
the scutellum. Some rather pretty bugs of the genus Scutellera, belonging to
the same subfamily, and characterised by a similar large scutellum, are found
in Australia and the Eastern Archipelago. They are of a short, broad, and
convex form, and have a very fine metallic -blue coloration, often spotted with
bright yellow. The forest -bugs (Pentatoma) have strongly projecting angles
to the prothorax, and have a long triangular scutellum. The species figured
(P. ruji'pes) is common throughout Europe, on birch and other trees, and renders
service by destroying certain caterpillars. We figure on the opposite page three
other species of this family — Acanthosoma dentatuvi, which is common on
willows ; Ewrydema oleraceum, a bluish green or metallic green species, with red
or white markings, which in some places is injurious to plants of the cabbage
tribe, but also lives on other plants, and has often been seen to prey upon insects ;
and another common species met with near the outskirts of woods and in fields
and meadows.

The family Coreidce includes a number of land-bugs, which vary a good deal
in form, but which possess in common the following characters, — antennae four-
jointed, set rather high up on the head ; two ocelli generally present ; scutellum
short and triangular; elytral membrane strongly and thickly veined. These bugs

RHYNCHOTA.

189

SHIELD BUGS.

mostly inhabit the warmer parts of the world, not more than about sixty species being
found in Europe. Their habits are not very well known. Some of the European
species live during the winter under leaves, and when disturbed in their retreat
make by their movements a peculiar rustling sound. In summer they are to be
found among herbs and
shrubs seeking their
food, or they may some-
times be seen flying
actively in the sunshine.
Our figures — one repre-
senting a stout, strongly-
built insect (Syromastes
inarginatus), the other
a species {Neides tipu-
larius) with a body as
slender almost as that of
a daddy long - legs —
illustrate what consider-
able differences of form
are met with in this
family, even among the
common European
species. The Lygceidce,
the next family of land-
bugs, may be character-
ised as follows, — antennae four-jointed, arising from below an imaginary line drawn
from the middle of the eye to the base of the rostrum ; two ocelli usually present,
and placed close to the compound eyes ; sheath of rostrum composed of four nearly

equal joints; scutellum short
and triangular; membrane of
elytra traversed by four or five
longitudinal veins. They live,
for the most part, under stones,
dead leaves, or moss at the foot
of trees, where they are often
found together in large num-
bers ; and it is from their love
of such obscure places that the
name Lygcews has been given
to the typical genus. They
feed on the juices of plants or
the dead bodies of other insects.
A few species only show them-
selves in broad daylight. The species of the genus Pyrrhocoris, and others
associated in the same subfamily, are distinguished by the fact that they have
no ocelli. P. apterus is a common and widely-spread European species, occasionally

1, Pentatoma rufipes ; 2, Acanthosoma dentation ; 3, Eurydema oleraceum ;
4, Aelia acuminata (nat. size).

1, Syromastes marginatus ; 2, Larva of the same ; 3, Neides
tipularius (nat size).

190

INSECTS.

Pyrrhocoris ajpterus (three
times the nat. size).

met with in Britain, which may be known by its red and black colours, and the
want of hind-wings, as well as of a membranous part to its elytra. The plant-
bugs (Phytocoridw) have the following characters. Head triangular in shape,
tricarinate above, and without ocelli ; antennae long, four-
jointed, with the second joint longest, and the last two very
slender ; rostrum four-jointed, resting against the under side
of the thorax, and almost reaching to the end of it; tarsi
three-jointed ; elytra with an appendix, or small angular
piece, divided off by a transverse suture from the rest of
the coriaceous part of the elytra, and coming between it and
the membrane. This family is well represented in temperate
regions, and about three hundred European species are known.
They are mostly soft-bodied, fragile bugs, presenting a con-
siderable variety of colour, of which green is in many cases
the predominant tint. They live principally on honey, and
are to be found on flowers and in meadows. Phytocoris
tripustulatus, a species with black elytra, marked with three
orange spots on the outer margin, is common on nettles. We give an enlarged
figure of another species {Calocoris striatellus), widely distributed throughout
Europe, and met with chiefly on umbelliferous plants. The Acanthiidce form a
family of mostly very small bugs, which are usually without ocelli, and have a
three -jointed beak — lodged in a groove along the under side of the head — and
two-jointed tarsi. These bugs frequently have a somewhat peculiar appearance^
owing to the membranous or vesicular lobes with
which the thorax, abdomen, and elytra are often
furnished. For this reason they are sometimes
known as membranaceous bugs. The species of the
genus Tingis are seldom more than one-sixth of an
inch long, and distinguished by the knob-like ends to
their antennae, as well as by the foliaceous expansion
of their thorax, and the extension of the latter behind
to cover the scutellum. The common T. affinis may
be recognised by the brown colour of its body, its
transparent borders, with transverse brown nervures,
and the X -shaped spot on the middle of each elytron.
This species may be found on sandy soil among the
roots of grasses, or under plants, such as wormwood,

belonging to the genus Artemisia. Another species (F. pyri) is noted for the
injury it does to pear trees, by pricking holes in hundreds on the under side of
the leaves and extracting the sap. It is of a brown colour, with pale yellow or
white elytra, marked with a brown spot at the base and another at the extremity.
Aradus corticalis is a common species, found under bark, which we figure to give
an idea of the flattened form and membranous appearance of the bugs of the sub-
family Aradincs. These bugs have a longer rostrum and more cylindrical antennae
than those of the Tingitince. The bed-bug (Cimex lectularius), which also belongs
to this family, is a wingless species, with four-jointed antennae, and a beak composed

Calocoris striatellus (much enlarged).

RHYNCHOTA.

191

1, Tingis affinis ( x 8) ; 2, Aradus corticalis ( x 6) :
3, Cimex lectularius (much enlarged).

also of four joints, which can be turned back to lie in a groove under the throat.
The shape of the insect may be seen from the figure, as well as the two lobes lying at
the sides of the scutellum, which are all it has in the way of elytra. Closely-allied
species are found in dovecots, and in the
nests of martins and bats. The
Reduviidce are predaceous bugs, in
which the head, narrowed behind in the
form of a neck, carries two ocelli in
addition to the compound eyes. Their
antennae are composed of four joints,
though these are often subdivided in
such a way that the number may
appear much greater. The rostrum is

short and strong, and three-jointed ; their legs are long, and have three-jointed
tarsi ; and the fore-legs often serve as prehensile organs, their tarsi being specially
adapted for that purpose. Beduvius personatus, the largest British species, is

three-quarters of an inch long, of a,
black -brown colour, with red legs,
which, as well as the prothorax and
antennas, are somewhat hairy.

The Saldidce, which, on account
of their large projecting eyes, are
sometimes known as Oculati, form
with the next family a sort of tran-
sitional group between the land-bugs
and water -bugs. They live in the
neighbourhood of water, either by
the seashore or along the sandy banks
of inland waters; and not only run
with great rapidity, but often advance
with leaps and bounds, their long spiny hind-legs being well fitted for this mode
of locomotion. One of the species of the typical genus Salda is represented in
the illustration. The pond -skaters (Hydrometridce) have moderately long con-
spicuous antennae, and present other points of structure showing
that they are nearly related to the true land - bugs. In some
species wings, and in others, elytra also, may be wanting. These
insects may be seen walking or gliding about on the sunny surface
of stagnant or slow - flowing waters ; and those of one genus
(Halobates) are found on the surface of the sea, sometimes right
out in mid-ocean. The true pond-skaters (Gerris) move about
very quickly on the surface of the water, and use their fore-legs
in seizing their prey. Limnobates stagnorum is a more sluggish
insect, walking slowly on the surface of the water, or on the
grassy banks ; and is remarkable for its elongated slender body,
whence its name of needle-bug or water-gnat. This species is figured on p. 192,
together with Gerris pallidum and the larva of Velia currens.

Reduvius personatus and its larva (nat size).

Salda elegantula
(greatly enlarged).

192

INSECTS.

Water-Bugs.

The water-bugs, Hydrocorisa,are distinguished from the land-bugs,
not only by their mode of life, but also by their short inconspicuous
antennae, and are mostly dull and uniformly coloured insects, frequenting stagnant
waters, where they swim some on their back, others with the back uppermost. They
are all comprised in two families. Of these, the water-scorpions {Nepidce) have a
small narrow head, and their fore-legs are specially modified to serve as prehensile
organs. Whereas some swim actively, others drag themselves slowly along the

COMMON* BRITISH WATER- BUGS.

1, The water boatman (Xotoneda glaum) ; 2, The water-scorpion (Nepa cinerea), with (3) its larva and (4) its eggs ;
5, Naucoris cimicoides ; 6, Corixa geoffroyi ; 7, Ranatra linearis ; 8, Limnobates stagnorum ; 9, Pond-skater
[Gerris pallidum), with (10) its eggs and larvae ; 11, Larva of Velia currens (nat. size).

bottom of the ponds in which they live. They are furnished with an appendage
looking like a long tail, but consisting of two separate pieces, grooved on their inner
surface, and capable of being locked closely together to form a tube, which leads
to the two spiracles placed at the hind-encl of the body. When the insects come
up to breathe, the tip of this breathing-tube may be seen emerging just at the
surface of the water. The form of the body is in some {Nepa) broad and flat ; in
others {Ranatra) elongated. The female of Nepa lays her eggs in chains on
aquatic plants, and each egg has seven short processes radiating from one end.
The eggs of the Ranatra are laid one by one in notches, which the female makes in
the stems of the plant.

RHYNCHOTA.

*93

Certain exotic species of this family are remarkable for their great size, attain-
ing in the genus Belostoma a length of over 4 inches. The water-boatmen
(Notonectidce) may be recognised by the large broad head without ocelli, and the
short thick rostrum. They have long hind-legs fringed with hairs on one side,
which they use like oars in swimming. When the insect comes to the surface to
breathe, it rests with these long legs, stretched out like a boatman leaning on
his sculls. Though the name Notonectidce has reference to their mode of
swimming on the back, this habit is not characteristic of all the species. All
are predaceous bugs, like all the rest of the same tribe, and are found abundantly
in stagnant waters. Two of the common species, Notonecta glauca and Gorixa
geoffroyi are figured on p. 192.

The Homoptera present much greater variety in external form than the
insects of the preceding group, from which they differ in the following characters.
The beak arises from the lower and hinder part of the head, and is, therefore,
almost completely hidden from view. The fore-wings are, when present, of the
same texture throughout the whole of their extent, and, in many cases, placed
slanting, like the
sides of a roof, when
at rest. All the
members of the
section live by
sucking the juices
of plants ; the
females being often
provided with a
horny ovipositor —
generally composed
of three toothed
plates, sheathed by
two valves — for the
purpose of making
incisions in plants
where the eggs are
deposited. Unlike
most bugs, they are

not odoriferous insects, although many have special glands for the secretion of a
kind of white waxy substance, often seen covering part of their body. The
cicadas (Cicadidce) are stout -bodied insects, with a short broad head, bearing
prominent lateral eyes, and three distinct ocelli, which are often brightly coloured
and resemble tiny jewels set near the middle of the forehead. The short
antennae are like small bristles inserted on the sides of the head just below the
front margin of the eyes. The prothorax is short and broad, and the mesothorax
also broad, on the upper side stretching back some distance behind to form a
kind of shield. The fore-wings are longer than the hind-pair, both being often
glossy and transparent, but sometimes finely coloured and more or less opaque.
Cicadas remain for a long period in the larval state, in many cases for several

vol. vi. — 13

EUROPEAN CICADAS.

1, Cicada orni ; 2, C. plebja and larva.

i94 INSECTS.

years ; a North American species, Cicada septemdecim, being known as the
seventeen-year locust, since that period is the interval between one generation
of winged insects and the next. They inhabit chiefly the warmer regions of
the earth, of the four or five hundred species known, not more than eighteen
being found in Europe, and these mainly in its southern parts. The song
of the cicadas, which has been celebrated from very early times, is only
produced by the male insects. " Happy " writes a Greek poet, " are the
cicadas' lives, for they all have voiceless wives." The females are necessarily
silent, since they are without the special apparatus for producing sound
distinctive of the males. The two scaly plates which in the latter cover
the under side of the base of the abdomen, are not, as sometimes supposed, the
sound - producing organs. But if one of them be stripped off, there will be
disclosed a cavity, divided by an oblique horny ridge into two portions,
the inner one somewhat irregular in shape, and exhibiting tense glistening
membranes in its walls, while the outer portion is narrow, and opens by a
narrow mouth towards the side. Hidden in the wall of the latter chamber lies
the membrane which is the chief organ concerned in the production of sound.
These membranes are set in vibration by the contraction and relaxation of a pair of
strong muscles attached to their inner faces and lying inside the body. The other
membranes in their neighbourhood seem to serve the purpose only of modulating
the sound. The cicadas figured are two of the commoner species from South
Europe. Both live on ash trees, although Cicada omi selects by preference the
manna ash. The specimen with its under side exposed may be easily recognised as
a male, on account of the two plates, or opercula, covering the cavities in which the
sound-apparatus is lodged.

The lantern-flies and other insects included in the family Fulgoridw are
characterised by never having more than two ocelli, these being placed, one on
each side, near the inner margin of the compound eyes. The latter are not large,
and below them are inserted the short and inconspicuous antennse. The front,
vertex, and sides of the head are usually separated from one another by sharp
crests, and the head itself is in some cases greatly prolonged in front. The fore-
wings are either similar in texture to the hind-pair, or else somewhat harder and
more leathery. The Chinese lantern-fly {Hotinus candelarius), so widely distri-
buted in Asia, is one of the best known ; the common names said to be given to it
in China being very suggestive of its luminosity, although so far there is no trust-
worthy evidence to show that it possesses any such property. Lantern-flies are
nearly all prettily coloured ; and of the other insects belonging to the same family
there are some, like those of the genus Flata, rivalling in the delicacy of their
colours the most beautiful butterflies or flowers ; while others, as in the genus
Flatoides, exhibit that curious mixture of grey and black, which, in combination
with the flattened form of their bodies, gives them the most astonishing resemblance
to lichen-covered bark. The species of Flata and other genera are remarkable
also for their white tufted tails of wax, which are found more especially in the
larvae, but are often present also in the winged insects. These insects do not stir
far from their food-plant, on which they may be seen both in the larval and adult
state, clustered together in large numbers, somewhat after the manner of plant-lice.

RHYNCHOTA.

i95

Cixius nervosus (enlarged).

The European species of Fulgoridce are not remarkable for their size or the
brilliancy of their colours. Jssus coleoptratus is perhaps the largest British species,
and we figure Cixius nervosus, another widely dis-
tributed British and European species, together with S-
Pseudophana europcea, the sole representative in
Europe of its genus, and sometimes spoken of as the
European lantern-fly.

The frog-hoppers (Cercopidce) are mostly small
insects with a short broad head and stiff opaque
elytra. They usually have two ocelli placed on the
vertex of the head between the compound eyes ; and
their antennae are inserted, not below the eyes as in
the Fulgoridce, but between and a little way in front of them. These insects can
give most vigorous leaps, and their hind-legs are generally thickened or other-
wise adapted for that purpose. They feed
on various plants, and in the summer the
frothy masses in which their larvae lie con-
cealed may be seen in numbers. It is from
this habit the larvae have of surrounding
themselves in a mass of froth, known as
cuckoo - spit, that the name Aplirophova
(froth-bearing) has been given to one of the
principal genera. A species of that genus is
shown in the illustration on p. 196, where
another form (Ledra aurita) — remarkable
for an ear - like lobe on each side of the
prothorax — is also figured. The family
Membracidce includes mostly exotic insects, which have in many cases an extra-
ordinary appearance, owing to the shape of the prothorax, or the curious way in
which it is armed with spines or knobs, or with both combined. In these insects
the head is somewhat vertical, and usually placed rather low down ; it carries very
short antennae inserted near the front margin ; and there are two ocelli between
the compound eyes. The family is best represented in Tropical America, very few
species being found in Europe, and two only in Britain. Centrotus cornutus, one
of the two latter, may be recognised by the form of its prothorax, which carries
on each side a horny spine, and is prolonged behind in another horny process,
reaching almost to the end of the body.

The leaf -fleas (Psyllidce) — included with the next two families in that section
of the order to which the name Phytophthires has been given — are little
jumping insects, winged in both sexes, and using their wings not so much for
the purpose of flying as to assist in their leaps. They have moderately long
antennae, consisting of eight or ten joints, and are thus easily distinguished
from the Cercopidce. The head is provided with three ocelli, in addition to the
compound eyes; and the tarsi are two -jointed. Owing to their method of
locomotion, these insects are not liable to be mistaken for plant-lice, although, like
these insects, they infest the leaves and buds of plants. They prick the leaves to

Pseudophana europcea.

196

INSECTS.

feed on the sap, their puncture being often followed by the formation of gall-like

swellings. The figured Psylla genistce feeds on the broom, but other species are

found on apple and pear trees. The plant-
lice (Aphidce) are small insects, which make
up in numbers what they lack in size, and,
owing to the injury they inflict on plants,
must be ranked amongst the greatest pests
with which the gardener and horticulturist
have to contend. They are those soft, pulpy
little creatures, with rather long antennae
and conspicuous round eyes, so commonly
seen crowded together on the under side of
leaves, in buds and flowers, in clefts in the
bark of trees, and sometimes even on the
roots. The antennae are composed of from
three to seven joints, on some of which are
a number of curious rounded pits, probably
of a sensory nature. The eyes are placed
on the sides of the head, and each has
often a sort of supplementary eye attached
to its hind border; while in the winged
aphides there are three ocelli on the crown
of the head. The beak is composed of
three joints ; and the tarsi are two-jointed
and terminate in two claws. Wings, as a
rule, are found only in the adult males and
in some of those generations of asexual
individuals to be mentioned presently. The

fore- wings are longer than the hind-pair, and placed in repose like a roof over the

hind part of the body. Both pairs

have a scanty venation, consisting in

each wing of a single longitudinal

vein, and of some simple or forked

branches given off obliquely from it.

The number of species is considerable,

and there is scarcely a single kind of

plant that does not suffer as the

special host of some one or more.

Many are green, whence the name of

green -fly by which they are com-
monly known ; others are black, red,

or some other colour,

1, Ledra aurita ; 2, The same seen from the side
(both enlarged) ; 3, Aphrojolwra spumaria ; 4,
Larva of the same.

Centrotus comutus (slightly enlarged).

Psylla genistce (six times nat. size).

They are usually named after
the plants on which they more particularly live,
though each species is not necessarily confined to one
kind of plant. Thus we have the plant-louse of the
rose {Aphis rosce) ; the green aphis of the apple (A.

RHYNCHOTA.

197

rnali), which is found also on the pear and sloe tree ; the cherry aphis (A. cerasi),
and a host of others named in the same manner. The life-history of plant-
lice is very complicated; and although differing somewhat in different species
is always characterised by what is known as an alternation of generations.
There are several broods or generations of these insects in the course of a year,
but it is only in the last autumn brood that true sexual individuals are found.
The males are generally provided with wings, but the females are larger

vine-phylloxera (much enlarged).
1 and 2, The wingless form found on the root, seen from above and below ; 3, The same from the side ; 4, Its
piercing organs ; 5, Winged individual ; 6, Rootlets of the vine, with swellings caused by the Phylloxera ;
7, An old root stock, with (8) hibernating individuals.

and wingless; they lay fertilised eggs, from which, in the following spring,
the first brood of the year is produced. The insects of this brood are usually
wingless, and give birth to living young, or, as in the genus Phylloxera, lay eggs
from which the young subsequently develop. The new brood, thus produced
parthenogenetically, resembles the one from which it has sprung, and gives rise to
a fresh brood in a similar manner. As many as nine or ten generations may
succeed one another in this way during the course of the season, before the appear-
ance in the autumn of the last or sexual generation. The brood preceding and

198 INSECTS.

giving rise to the latter often consists of winged individuals, which leave the plant
on which they were born and fly to some other. In the genus Phylloxera, the
males are wingless and each of the sexual females lays but a single egg, known as
the winter egg ; but in other forms the number is often much greater. Each of
the parthenogenetic females of Phylloxera may in the course of its life lay as
many as two hundred eggs, and each of the viviparous females of other species may
give birth before they die to forty or fifty young. When we consider that there
are several generations every year, it can be easily understood how it is that these
insects spread with such rapidity ; and a sum in geometrical progression would
show that the individuals which might arise in the course of a year from a single
winter egg of Phylloxera, are not to be counted by hundreds or thousands, but by
millions. Other species are capable of multiplying as rapidly. Fortunately,
plant-lice have many enemies, such as the larvae of lady-bird beetles, of lace- wing
flies, and of the flies of the family Syrphidai. These larvae devour great numbers,
and ichneumon-flies also help to keep them in check. Plant-lice are divided into
a number of subfamilies, of which the first is represented by the genus Aphis. In
this genus the antennae are seven-jointed and about as long as the body ; the two
horny tubes called cornicles, which project from the back of the abdomen, are also
characteristic. Through these tubes the lice secrete a sweet kind of liquid much
sought after by ants, who, in an affectionate way, come and caress the aphides in
order to obtain it. The sticky substance known as honey-dew, which is often
spread in a shiny layer over the upper surface of leaves, is, in most cases, nothing
but the liquid dropped by the crowds of plant-lice living above on the under side of
other leaves. The members of the allied subfamily Lachninai have six-jointed
antennae, and instead of cornicles possess prominent grandular structures placed on
the back of the abdomen. The figured Lachnus punctatus is found on the willow.

The apple-blight insect (Schizoneura lanigera),
which may be recognised by the white fluff
covering in the wingless individuals the back
of the abdomen, belongs to another subfamily.
The winged individuals of this species are
black, whereas those devoid of wings are of a
\ / yellowish or reddish brown colour, and live in

Lachnus punctatus (six times nat. size). the crevices of bark. The species is supposed

to have been introduced from America, and was
consequently at first known as American blight. In the genus Phylloxera — •
distinguished among other characters by the three-jointed antennae — one species
lives on the leaves of the oak-tree, while a second (P. vastatrix) is the dreaded
insect so destructive to the leaves and roots of the vine. These, like many other
species of the family, cause the formation of galls on the leaves and roots which
they attack. The curious galls with the appearance of small fir cones, so often
seen on young shoots of the spruce-fir, are caused by a species {Chermes abietis)
remarkable for its complicated life-history.

The scale-insects (Coccidai), which owe their name to the fact that the larvae
and females of many species look like oval or rounded scales attached to the bark
and leaves of plants, are very dissimilar in the two sexes. The adult males are

RHYNCHOTA.

199

spruce-gall aphid {Chennes abietis).
Larva ; b, An older larva with its moulded skin still
attached to it ; c, Winged insect ; d, The gall. (All
enlarged.)

provided with one pair of wings ; the hind-wings being rudimentary or altogether
absent; they have rather long antennae, distinct eyes, and, in some cases, are
furnished with two long bristle -like «

tails. These winged males are very
rarely seen, which is accounted for by
the fact that their mouth -parts are
atrophied, so that they are incapable of
taking nourishment, and live only a
short time. The females are always
wingless, and usually remain fixed to
one spot, with their beak buried in the
tissues of the plant, and their back
often spread out in the form of a shield
covering the head and body. The beak
is generally three-jointed, the antennae
are short, and in the tarsi, which appear
at first sight to consist of but one joint,
two or three joints may on close examination be distinguished, the last ending, as
a rule, in a single claw. In many species the female dies shortly after laying eggs
beneath her when her body dries up and remains as a protective cover for them.
When the larvae are hatched they soon leave this shelter, and rove about the food
plant in search of a suitable place in which to insert their beaks and begin the
operation of pumping up the sap. They cast their skin several times in the course
of their growth ; and those which become adult females undergo no great change
in appearance, beyond an increase in their size, a gradual lengthening of the

antennae, and a partial or almost complete obliter-
ation of the segmentation of their bodies. With
the male larvae the case is different ; these, unlike
all others belonging to the order, undergoing a true
metamorphosis before reaching the perfect state.
Each prepares for itself a sort of cocoon, and
it becomes transformed into a quiescent pupa,
from which, after a certain lapse of time, the
winged insect emerges. In Orthezia and other
genera the female, instead of keeping to one spot
on the food-plant, moves about and taps it at
different points in order to extract the sap.
When the eggs are laid, she envelops them in
a kind of white cottony secretion and leaves
them. Some species penetrate beneath the
epidermis of their food -plant, and often cause
the formation of galls, which, growing up around
them, sometimes take the most extraordinary
shapes. Scale-insects are probably more numerous within the tropics than in more
temperate regions, although comparatively few of these tropical species have been
described. These insects are found on the bark and leaves, and sometimes

female of Orthezia urticce (nat. size).

INSECTS.

even on the roots of several different kinds of plants. They multiply rapidly,
and often prove as injurious as the most noxious plant -lice. The orange,
apricot, olive, peach, fig, and other fruit trees, as well as ornamental shrubs
like the rose, have each their own species, from which they sometimes suffer
severely. Some years ago the orange-plantations of California were threatened
with ruin owing to the ravages of Icerya purchasi, which had been accident-
ally imported from Australia, and had spread with great rapidity. Experts
were sent to Australia to try and discover the natural enemies of the insect
in its native country; it was found that the scale-insect was there kept in check
by dipterous and hymenopterous parasites, but chiefly by the larvas of a lady-
bird beetle. A number of these beetles and parasitic insects were brought to
America, and set to prey upon the Coccidce. When they had multiplied sufficiently,
they were distributed amongst several orange-plantations, with the result that
many were soon almost entirely cleared of the scaly-bug. Though many species

cochineal insect (Coccus cacti), with enlarged figures to the left of (1) the male and (2) female.

of Coccidce have to be combated because of their injuries, there are a few which
are cultivated on account of the useful products they yield. Among these, the
cochineal insect {Coccus cacti) is a native of Mexico and other parts of Central
America, where it feeds on a species of cactus ; but it has been introduced into
Spain, Algeria, and a few other countries. The male is of a dark red colour, with
pale wings ; the female has a reddish brown colour, but her body, which shows a
distinct segmentation until the time of laying, is covered with a white powder.
About seventy thousand dried bodies of these insects, chiefly females, are said to be
contained in a single pound of cochineal. Long before the introduction of cochineal
into Europe, two native species of Coccidce had been used for similar purposes.
The dye with which the ancients produced their deep red or crimson colours was
obtained from Cermes vermilio, known to the Greeks as kokkos and to the
Arabians and Persians as kermes or alkermes. Another species (Porphyrophora
polonica), formerly known as the scarlet grain of Poland, is found in many parts
of Central Europe, and was at one time extensively collected for the sake of the
red dye it afforded. The lac-insect (Carteria lacca) of the Oriental countries,

THYSANOPTERA. 201

not only furnishes the colouring matter called lac-dye, but causes also an exudation
of a resinous substance, gum-lac, from the bark of the trees on which it lives.
Stick-lac is the name given to this substance in its native state while still adhering
to the twigs of the tree ; when separated, pounded and freed by washing from its
colouring matter, it is known as seed-lac, which after further preparation becomes
lump-lac or shellac.

The Pediculina, or true lice, as distinguished from the bird-lice of the order
Orthoptera, are provided with piercing and suctorial mouth-parts, and live on
the blood of animals, to which by this means they are enabled to gain access.
Though they are without wings, and were at one time associated with other
wingless insects in a separate order, lice are now generally regarded as de-
graded forms of Rhynchota, in which the
wingless condition has been brought about
as an adaptation to their parasitic life. In
these insects the head is set horizontally, and
carries short, cylindrical, and usually five-
jointed antennae; the eyes are small and ^head-louse with its eggs ; 2, body- louse ;
simple ; and the mouth consists externally of 3, crab-louse. (All greatly enlarged.)

a soft, retractile beak, somewhat conical in

shape, and furnished below with a row of hooks for attachment. Within the
fleshy beak there are four grooved pieces, forming by their juxtaposition an inner
membranous tube, which can be extended beyond its sheath, and acts both as a
piercing organ and as a conduit for the passage of the blood which is sucked up by
the insect. The thorax is small and not distinctly divided into segments, while the
abdomen is relatively large, generally somewhat elliptical in outline, and exhibits
seven or eight clearly marked segments. The tarsi are two -jointed, with the
second joint in the form of a claw which can be turned back towards the first.
Lice multiply rapidly, one generation succeeding another in a short space of time.
Their pear-shaped eggs are generally found attached to the bases of the hairs ; the
young, which are hatched after about eight days, undergo no metamorphosis, and,
in some cases, require only about eighteen days before becoming adult.

Order Thysanoptera.

The insects comprised in this order — some of them familiar enough to gardeners
and others, by whom they are known as thrips — are all small. A few species only
exceed four or five lines in length, while the great majority are less than a tenth
of an inch long. They are distinguished from all other insects by certain
peculiarities in the structure of their mouth and of their wings and tarsi. The
mouth lies far back on the under side of the head ; its mandibles are transformed
into a pair of piercing setae, while the upper lip, maxillae and labium — the two
latter, provided with short palpi — are united together to form a short suctorial
tube. The wings are small and narrow, contain few nervures, and are thickly
fringed all round with long hairs. Two pairs of such wings are generally present,
but in some cases they may be rudimentary or altogether wanting. The tarsi,
which consist of one, two, or three joints, are without claws at the end, but are

INSECTS.

Hdiothrips hcemorrhoidalis
(greatly enlarged).

furnished instead with small vesicular lobes, by means of which they adhere to
the surface on which they rest. To these characters of the order we may add that
the body is narrow and cylindrical ; the
thorax is formed of three, and the ab-
domen of ten segments ; there are only
three or four pairs of spiracular openings
— two on the abdomen, and one or two
on the thorax ; three ocelli are generally
present on the head in addition to the
fairly large faceted eyes ; and the
antennae are composed of from seven to

nine joints. The larvae have a general resemblance to the adult
insects, and in their last stage they remain inactive and take no
nourishment. Less than a hundred species of Thysanoptera,
belonging mostly to the European fauna, have been described.
These little insects are frequently to be seen on flowers, and on
other parts of plants. They feed upon the juices, and when present in large
numbers are capable of doing an appreciable amount of injury. Some destroy
the pollen grains, and so prevent the fertilisation of the flowers. The corn-thrips
(Thrips cerealium) sucks the young grains on the ears of corn, and stops their
further growth. Heliothrips hcemorrhoidalis, another species which we figure, is
common in hothouses, where it may be found on the young buds of several
different kinds of plants.

Order Thysanura.

FEMALE CORN-THRIPS

(much magnified).

The Thysanura are active little insects, which live generally in obscure places
and are mostly of too small a size to attract much attention. They never exhibit
any trace of wings, undergo no metamorphosis, and have a distinctly segmented
body, which is usually covered with hairs or scales and furnished behind either
with a forked tail, used as a springing
apparatus, or with two or three long, jointed
appendages, which sometimes serve a similar
purpose. Characterised on the whole by a
somewhat primitive type of structure, and,
in general appearance resembling the larvae
rather than the adult forms of other insects,
the Thysanura are in some cases distinguished
by special features of great interest. The
spring-tails (Collembola) are all furnished on
the under side of the first abdominal segment
with a curious tube or sucker, from the
mouth of which a glandular process, secreting
a viscid matter, can be protruded ; they are

remarkable also from the fact that in most of them no trace of a tracheal system
has yet been discovered. In the Collembola the eyes, when present, are in the form
of simple or grouped ocelli ; the antennae number not more than six joints, and the

Podura villosa (nat. size and greatly enlarged).

THYSANOPTERA. 203

abdomen has at most but six segments and very often only three. The forked tail,
which is attached to one of the hinder segments, is usually turned forwards and held
in position under the body ; when released, it springs back, striking the surface of
support, and causes the insect to bound up into the air. These little insects are to
be found commonly enough under flower-pots, leaves, and stones, or under the
bark of trees and in other such situations. They may sometimes be seen collected
together in great numbers, and spread over the surface of the ground like a layer
of powder. Some species, such as Podura aquatica, may frequently be seen floating
in patches on pools of water, and by striking
their tails against the surface of the water, they can
spring up into the air just as readily as others do
from the ground. Desoria glacialis is an inter-
esting species, found in Alpine regions, where it is

often to be met with on the Surface of the ice. Desoria glacialis (greatly enlarged).

The bristle -tails (Thysanura proper) form but a

small number of genera, some of which are very remarkable in having a series of
small rudimentary legs on each side of the abdomen in addition to the ordinary six
legs borne by the thorax. In all the genera the antennas are formed of a large
number of joints ; and the abdomen shows ten distinct segments, and, except in the
genus Japyx, carries at the end two or three long jointed tails. Japyx has instead
a pair of short pincers like an earwig. The little silver-fish {Lepisma saccharina)
is one of the best known insects belonging to this suborder. Found very often in
damp corners in houses, among old books or papers, it may be recognised by the
silvery scales covering its body, and by its three bristle-like tails, of which the
middle one is the longest. It feeds on the paste in the binding of books, and on
sugary and starchy substances generally, though it is credited also with eating
paper and linen. Thermophila furnorum is a species which lives in bakehouses,
where, as its name implies, it is often found in the ovens.

Machilis is one of the genera in which the abdomen is provided with rudi-
mentary legs in the form of small cylindrical appendages, each of which is
accompanied by two small protrusible sac-like organs. An appendage similar
to those on the abdomen is attached to each of the coxas of the two hinder pairs
of legs. The body, covered over with scales, is arched up in the middle, as in
Lepisma, and carries three tails. The eyes are large and faceted ; and the palpi
are long, those of the maxillse looking like a second pair of antennas. Two species
of this genus are found in Great Britain ; one being common about rocks at the
seaside, while the other is to be met with under stones in different parts of the
country. Campodea staphylinus, the last insect we have to mention, is a pale,
soft-bodied little creature, which is common almost everywhere under stones and
in loose garden soil. It runs actively, and has two very long tails which it sticks
up in the air or turns forward over its body. It has no eyes ; the antennas are
shorter than the tails and of equal thickness throughout ; and the abdomen has
seven pairs of rudimentary appendages.

C. J. GAHAN.

CHAPTER VI.

Jointed Animals, — continued.

Centipedes, Millipedes, Scorpions, and Spiders, — Classes
Chilopoda, Diplopoda, Arachnida, etc.

Characters of According to modern views, centipedes are regarded as near allies
Centipedes. 0f insects, the chief differences between the two groups being that
whereas in the latter there are only three pairs of jaws attached to the lower
surface of the head, in the former four pairs of appendages are modified to act
as masticating organs. Moreover, the body of an insect is sharply divided
into an anterior portion, or thorax, bearing three pairs of walking legs, and a
posterior half, or abdomen, which in the adult at least is not provided with
locomotor limbs, but the body of a centipede is composed of a large and varying
number of segments, substantially alike in structure, and each bearing a single
pair of legs. The number of segments varies from fifteen to considerably over
one hundred, yet no matter how many pairs of legs there may be — whether it be
fifteen or one hundred and twenty-one — their number is invariably odd.

The head bears a pair of elongate antennse in front, and often eyes arranged
in two clusters at the sides. On its lower surface may be seen the four pairs
of jaws. The first pair, or mandibles, are two-jointed and have a biting edge ;
the second pair, or maxillae, are soft, leaf-like, and united together in the middle
line, each consisting of an outer jointed and an inner unjointed branch. The third
pair, known as the first maxillipedes, are composed of four or five segments, and
much resemble one of the walking limbs, being tipped with a claw. The fourth
pair, or second maxillipedes, are large, powerful, and project forwards below the
rest, so as more or less to conceal them from view. Their basal segments are
usually fused to form a massive coxal plate, while the rest of the jaw consists of
four segments, the terminal one being a long fang with a minute aperture at the
tip, through which exudes poison secreted by a gland lodged inside the appendage.
These two pairs of maxillipedes do not strictly belong to the head, since the dorsal
elements of the segments that bear them are either distinct, or are united with
the tergal plate of the following segment to constitute a. massive basilar plate.

The rest of the body is composed of a varying number of segments, each
consisting externally of a dorsal plate or tergum, and a ventral plate or sternum,
connected laterally by a softer pleural membrane, to which the legs are articulated.
These latter are usually short, composed of six or seven segments, and each is tipped
with a single claw, and often furnished in addition with spines. The last pair are
generally longer and stronger than the rest, and sometimes considerably modified

CHAR A CTERISTICS.

205

111

\

structure. Breathing is effected by tracheal tubes, which open by means
of stigmata, placed almost always upon the pleural membrane of the segments.

Centipedes are divided into two subclasses — Anartiostigma, or those with
unpaired dorsal stigmata, and Artiostigma, or those with paired lateral stigmata.
In the former group, which contains the single family Scutigeridce and the
genus Scutigera, the head is furnished with a pair of large, compound, faceted
eyes, the widely separated antennae are exceedingly long and thread-like; and
the body, although composed of fifteen segments, has only eight dorsal plates,
all of which except the last are furnished in the middle of the hinder border
with a single large respiratory stigma. The first pair of maxillipedes consists
of five segments, and the coxae of the second pair, or poison-jaws, are not
united; the legs are very long and their tarsi
composed of a multitude of minute segments.
The species of the genus Scutigera are distributed
over all tropical and subtropical countries. Most
are of small size, with the body only about an
inch in length, but in India and China there are
species (S. longicornis and S. clunifera) which
may reach a length of several inches. The
majority are vividly coloured with black and
yellow stripes or spots, and all are remarkable
for their extreme agility, and the readiness with
which, when handled, they part with their legs.
None are indigenous to Britain, but the common
South European S. coleoptrata has been introduced
into a paper-mill near Aberdeen, where, protected
by the artificial heat, it has become established,
and breeds. Unlike the rest of the centipedes,
which habitually shun the light, the species of
Scutigera may be seen in their native haunts
darting about and catching insects regardless

of the blazing sun. They are, however, by no means strictly diurnal, and the
American S. forceps will come out in numbers at night to feed on flies.

In the Artiostigma the stigmata are paired, and open upon the pleural
membrane of all or some of the segments. There are the same number of tergal as
of sternal plates ; the eyes, when present, are not faceted, but consist of simple
ocelli ; the antennae are stouter and not thread-like ; the first maxillipedes consist of
four segments, and the coxae of the poison-jaws are united. The subclass contains
the orders Lithobiomorpha, Scolopendromorpha, and Geophilomorpha. The first
of these approaches the Anartiostigma in many characters, particularly in being
furnished with fifteen pairs of legs, the coxae of which are of large size ; and in one
of the genera (Cermatobius), which forms by itself the family Cermatobiido?, the
tarsi of the legs are many -jointed. There are either six or seven pairs of stigmata,
situated upon the first, third, fifth, eighth, tenth, twelfth and fourteenth leg-
bearing segments in Henicops and Cermatobius, while those on the first have
disappeared in Lithobius. In the latter genus, which with Henicops makes up

BLACK-BANDED CENTIPEDE, Scutigera,

(nat. size).

206

CENTIPEDES.

the family Lithobiidce, the eyes consist of a cluster of ocelli on each side of the
head, while in the other two there is only one pair of ocelli. Except in
Cermatobius, the coxae of the last five pairs of limbs are furnished with organs
known as the coxal pores, which are the apertures of special glands.

The members of this order are found in all temperate and tropical regions,
living often in pairs under stones, logs of wood, etc. The species of Lithobius are
particularly abundant, and reach their largest size in the temperate parts of the
Northern Hemisphere. A few only have been recorded from India and Australia,
but none occur in Africa south of the Sahara, nor, with the single exception of a
possibly introduced species in South America. In the Southern Hemisphere the
genus is largely replaced by Henicops, which is represented in Europe and North
America by a single small species, but has many larger forms in South Africa,
Australia, New Zealand, and Chili. The single species of Cermatobius occurs in
Halmahira, one of the Moluccas. There are about half a dozen species of

Lithobius in the British Islands, one of
the commonest and largest being L.
forjicatus, represented in the figure.
Almost equally common and equally
large, although seldom found close to
houses, is L. variegatus, — a brightly-
coloured species with banded legs, — which
is confined to the British and Channel
Islands. The largest known species is
the handsome L. fasciatus, measuring 2
inches in length, and occurring in many
of the southern countries of Europe. In
all cases the females — which may be recognised by the presence of a pair of dwarfed,
claw-tipped appendages behind the last pair of legs — lay their sticky eggs one
at a time, and roll them in the soil until they become coated with earth, and
consequently protected from observation. The young, like those of Scutigera,
are hatched from the egg with only seven pairs of legs, the remaining eight
pairs being added during growth. The food of these centipedes consist of worms,
insects, etc., which are killed by the poisonous bite of their destroyer.

The second order, or Scolopendromorpha, contains the giants of the group, some
of the tropical species of Scolopendra reaching a length of almost 12 inches. The
legs vary in number from twenty-one to twenty -three pairs, and there are either
nineteen pairs of stigmata, as in the aberrant genus Plutonium from Italy, or
more usually nine or ten pairs situated upon the third, fifth, eighth (sometimes
also the seventh), tenth, and alternate segments of even number. The eyes are
either absent or consist of four ocelli on each side of the head, and the segments of
the antennas vary in number from seventeen to twenty-nine. The members of
this order are referable to four families, the Scolopendridce, Scolopocryptopidce,
Newportiidce, and Cryptopidce. Both the Scolopocryptopidce and Newportiidai
have twenty-three pairs of legs, but in the latter, which is confined to the South
American region, the legs of the last pair are clawless and have their terminal
segments many jointed and evidently functioning as antenna?, so that the

COMMON ENGLISH CENTIPEDE (uat. size

CENTIPEDES.

207

j€<^g,

<ez%

centipede (Scolopendra morsitans) devouring a beetle larva
(reduced).

centipedes may be said to have a pair of feelers at each end of the body. The
Cryptopidcv resemble the preceding in being blind, but have only twenty-one pairs
of legs. They are all of small size, rarely exceeding an inch in length, and are
spread all over the world, extending farther to the north than any other forms.
One, namely, Cryptops hortensis, is by no means uncommon in England. The most
important forms belong, however, to the Scolopendridai, which in number of
genera and species is far superior to the others. Like the Cryptopidcv they have
twenty-one pairs of legs, but the
tarsi of these appendages are
bisegmented, and there are four
eyes on each side of the head.
From the shores of the Mediter-
ranean in the west, and from
China and Japan in the east,
this family spreads southwards
over the entire Eastern Hemi-
sphere, while in America it
ranges from the Southern
United States to Chili and
Argentina. The larger members

of the group are a foot in length, and very venomous, although their bite is seldom
fatal to man. The Scolopendridce live under stones and logs, and in the tropics
frequently take refuge in bedding, boots, or clothes. Their food consists principally
of cockroaches, beetles, worms, etc. ; but they do not seem to be particular as to

diet, since some have been found devouring lizards of
larger size than themselves, and one kept for more than
a year in the London Zoological Gardens was fed upon
mice. The female lays her eggs in clusters like berries
on the ground in some damp obscure place, and coiling
herself round them remains immovable until the young
are hatched and have gained strength enough to scatter
in search of prey. When kept without food in captivity
the mother will feed upon her young. The growth of
these centipedes, and probably of all members of the
group, is accompanied by casting of the entire integu-
ment. The membrane at the back and sides of the head
splits, the head-plate turns forwards, and through the
aperture thus made the new centipede gradually
struggles, leaving behind the old skin with its posterior
segments retracted within those that lie in front like
the pieces of a telescope. The genera of Scolopendridce
present a strong family likeness to each other ; one of
the most remarkable being the African Alipes, which
has the last three segments of the last pair of legs
flattened and leaf -like. The reason of this modification is unknown, but the
creature is said to make a noise by knocking and rubbing its legs together.

UPPER SURFACE

Geophilus tenuitarsus
enlarged).

2o8 CENTIPEDES AND MILLIPEDES.

The order Geophilomorpha, represented by the family Geophilidce, includes the
long worm-like centipedes, with the segments varying in number from thirty-nine
to over a hundred. There are no eyes, and the short thick antennae are always
composed of fourteen segments. Each segment of the body, with the exception
of the first and last, bears a pair of stigmata and is double, an anterior portion being
cut off by a distinct joint. The Geophilidce, which are distributed all over the world,
with the exception of the polar areas, are subterranean in their habits, burrowing
after the manner of earth-worms, upon which they almost wholly subsist. Two
exceptions, however, to this rule must be mentioned, namely, Linotamia rnaritima
and Schendyla submarina, both of which have been obtained upon the shores of
Western Europe, beneath stones at low-water mark. Although this is a strange
habitat for animals, air-breathing species typically terrestrial can withstand
immersion in sea- water for many hours, and in fresh water from one to two

GEOPHILUS GRAPPLING WITH EARTH-WORM (nat. size).

weeks. Many of the species emit a phosphorescent fluid from glands opening
upon the sternal surface of the segments. In Europe the time for the appear-
ance of the phenomenon is between the end of September and the beginning
of November. Although its import is not understood, it appears to be connected
in some manner with the mating of the sexes. A small reddish species (Linotcenia
crassipes) is the one most commonly found exhibiting this phosphorescence in
England.

Remains of fossil centipedes referable to the existing groups occur in amber
beds belonging to the middle portion of the Tertiary period ; while mere aberrant
types have been discovered in the Palaeozoic rocks of the United States.

To a certain extent, connecting the centipedes with the millipedes and insects,
is the class Symphyla, containing the single genus Scolopendrella. This is repre-
sented by minute pale-coloured creatures, with long thread-like antennae, fifteen
or sixteen body-segments, and twelve pair of legs, each of which is armed with
two claws. It further differs from the centipedes in having only two pairs of
jaws, as in the millipedes. Scolopendrella, which includes two British species, also
occurs in North America, India, and Sumatra.

The Millipedes, — Class Diplopoda.

Although millipedes and centipedes were formerly united to form the class
Myriopoda, it has been discovered that the characters in which they resemble each

MILLIPEDES.

209

other are comparatively trifling, and that the present group is much less closely
related to the insects than are the centipedes. In addition to certain anatomical
features, millipedes differ from centipedes in the following points. They have only
two pairs of jaws, namely, the mandibles — which are usually three-jointed — and the
maxillae, which unite to form a large plate or gnathochilarium, acting as a lower
lip. Besides these two pairs of appendages, the head is furnished usually with two
clusters of eyes, and always with a pair of short antennae, never composed of
more than eight segments, and usually of seven. The body consists as in the
centipedes of a varying, often large, number of segments, some of which are
furnished with two pairs of legs, and thus represent two primitive segments fused
together. These segments are usually cylindrical in section, and although each

A sumatean millipede, Platyrrhachus mirandus (nat. size).

may consist of as many as five skeletal pieces, these are frequently fused together
to form a single horny ring. The sternal surface, or the area between the bases of
the legs, is generally reduced to a narrow strip, the legs being almost or quite in
contact in the middle of the lower surface. The stigmata or breathing apertures
are placed close to the base of the limbs on their outer side ; and in addition to
these apertures, there is often a pair of orifices in each segment (except the last
and the first four) giving exit to an odorous fluid which serves as a protection to
its possessors. The legs are short and generally composed of
six segments, tipped with a single terminal claw. The last
segment is devoid of appendages, and furnished with a pair
of movable flaps or doors, closing over the hinder end of the
alimentary canal.

Millipedes are divided into two subclasses, Pselaphognatha
and Chilognatha. The former, with the single family Poly-
xenidce, contains minute, rather soft-bodied forms, only about
one-tenth of an inch in length, in which the body is composed
of nine segments and bears thirteen pairs of legs. The head
and dorsal plates are furnished with transverse rows of
remarkably formed somewhat scale-like hairs, and there is a
great tuft of similar hairs upon the sides of each segment,
while the last joint is furnished with a backwardly projecting
tubular brush of straight bristles. The antennae are eight-jointed, and there are no
thick glands. These minute creatures live beneath stones or the bark of trees. A
species of the typical Polyxenus is shown in the illustration. In the Chilognatha

vol. vi. — 14

BRISTLY MILLIPEDE,

Polyxenus (enlarged).

MILLIPEDES.

SUMATRAN PILL-MILLIPEDE. SphfXOpceUS (nat. size).

the antennae are seven- jointed, and the body is not furnished with tufts of scale-like
hairs. The group is divisible into the orders Oniscomorpha, Limacomorpha, and
Helminthomorpha. In the former, as represented by the pill-millipedes, the body

is short and broad, convex above and flat
below, with the second and last segments
enormously enlarged, and capable of being
rolled up into a ball. The skeletal pieces
which compose the segments are distinct and
movably jointed together. Each typical
segment consists of seven pieces ; a large
and vaulted tergum forming the upper sur-
face and concealing the legs ; while beneath this on each side there is a small pleural
piece, and between this and the two legs two still smaller tracheal plates bearing the
stigmata. The legs are in contact in the middle line of the body, and those of the
last pair are enlarged in the male and transformed into a pair of clasping organs.
Of the two families into which the order is divided the Glomeridce, or small pill-
millipedes of Europe, have the antennae close together upon the front of the head
the eyes with a single row of ocelli, and the
body consists of only twelve segments. In
the Zephroniidce, or large tropical pill-
millipedes, the antennae are situated on the
sides of the head, the eyes are composed of
a spherical cluster of ocelli, and the body
consists of thirteen segments. In the South
African genus Sphcerotherium the last
pair of legs in the male is furnished with
a well developed stridulating apparatus,
consisting of a finely ridged plate, which
by being rubbed against a set of granules
on the inner surface of the last tergal shield,
gives rise to an audible sound. Although

no representatives occur in America, the order is spread over the Eastern Hemi-
sphere, the Glomeridce ranging over Europe and thence into India and Borneo, while
the Zephroniidce occur in South Africa, Madagascar, India, the Malay Peninsula,
Australia, and New Zealand.

The Limacomorpha, or slug-like millipedes, form a small group, containing but
two known genera and three species included in the family Glomeridesmidce.
The body is composed of nineteen or twenty segments, all of them being approxi-
mately equal in size and similar in form, and none of them abruptly larger than the
rest. The body is capable of being spirally coiled ; its segments are formed
much as in the Oniscomorpha, but the tracheal plates are not distinct. The last
tergal plate, although small, forms a hood which covers over the last pair of legs,
and these are modified in form as in the males of the Oniscomorpha. The rest of
the legs are composed of only six segments, the basal of which is much enlarged.
There are no true eyes. Glomeridesmus, the typical genus, is known from two
species, found respectively in New Granada and in St. Vincent ; the other genus,

ENGLISH PILL-MILLIPEDE (nat. size).

MILLIPEDES.

Zephroniodesmus, occurring in Sumatra. None of the species exceed a quarter of an
inch in length.

In the Helminthomorpha, or worm-like millipedes, which comprise the majority
of the species, the body is composed of from nineteen to over ninety segments, is
usually elongate and slender, and capable of being spirally coiled. The characters
by which this group may be distinguished from the two preceding are that the last
tergal plate forms a complete ring, enclosing the pair of valves and sternum, and
that the tracheal plates take the form of two median sternal pieces, to which the
legs are directly articulated. Moreover, the pleural scutes, although sometimes free,
are less distinct than in the preceding groups. The order is divided into the sub-
orders Colobognatha, Chordeumoidea, Callipodoidea, Iuloidea, and Polydesmoidea.
In the first of these the mandibles have undergone great degeneration, and in the
most modified forms (Siphonophora), the lower edge of the head (labrum) and the
lower lip (gnathochilarium) are together produced into a long, piercing snout. The
pedal laminae, or sterna, are always free and movable, as are rarely the pleurae.
The secreting pores are present on all the segments, with the exception of the first
four and the last ; the parts of the segments around the pores being sometimes
produced into wide plate- or rod-like processes covering the legs. The body
segments vary in number from about thirty to over seventy, although the largest
members of this group seldom exceed an inch in length, and are generally shorter.
These millipedes occur in the tropical countries of both hemispheres, one form
(Polyzonium germanicum) extending into Central Europe. In the Chordeumoidea
there are no excretory pores, but each segment bears six symmetrically-arranged
bristles. There are usually either thirty or thirty-two body segments ; the pedal
laminae are always free, and often the tergal plate is keeled, or furnished with a
large lateral pro-
cess on each side.
There is a pair of
eyes on the head,
and the jaws are
normally devel-
oped.

The Iuloidea,
which is the largest
suborder of the
worm -like milli-
pedes, contains
families which may
be distinguished

from the last group by having the pedal laminae united to the terga. Some of
the tropical species reach 6 inches or more in length, and are the largest millipedes.
Of the families, the Spirostreptidce are spread over all tropical countries, but
scarcely migrate into temperate climes ; while the Iulidce reach their maximum
development in Europe and the United States, and are only sparsely represented
in the Tropics. The Cambalidce are remarkable for the presence of crests and
tubercles on their segments.

millipede, lulus sctbulosus (enlarged twice).

MILLIPEDES.

flat millipede, Polydesmus complanatus (much enlarged).

The suborder Polydesmoidea is almost as extensive as the Iuloidea, its members
being spread over the habitable world. The largest species belonging to the genus
Platyrrhachus, which reach a length of several inches, occur in Tropical America
and the East Indies. In all, the number of segments is nineteen or twenty, or the
fewest amongst the Helminthomorpha. Eyes are wanting, and, as in the Iuloidea,
the segments form solid rings, owing to the fusion of the pleurae and pedal laminae

with the terga. Secret-
/

ing pores are generally
present on most of the
segments, though some-
times absent in members
of the family Cryptodes-
midw. When present,
they are almost always
borne upon large plate-
like processes, springing
from the sides of the
segments. In distribu-
tion this suborder is
cosmopolitan, the temperate forms being of small size, while some of the tropical
species are large and beautifully coloured.

In habits all millipedes seem to be very similar. Although mostly
vegetarians, feeding on soft roots, fruits, and succulent plants, one of the smaller
kinds of lulidce eats worms and decaying animal matter. They occur under
stones, logs of wood, or in rotten tree trunks in damp places; and in tropical
countries come out in numbers after rain, when they may be seen crawling over
the ground and climbing bushes. Moisture is necessary for their existence, and in
captivity they freely drink water or milk. Most are slow in their movements, and
never trust in speed to escape. When walking the body is kept fully extended, and
propelled by the legs, the movements of which resemble a series of waves passing
up the body from behind forwards. As already stated, many forms are devoid of
eyes ; but even those possessing well-developed visual organs appear scarcely able to
do more than distinguish light from darkness. As they crawl along, every inch
of the road is first carefully touched by the antennae, which are tipped with a
sensory organ, and the creatures appear to be unaware of the presence of an
obstacle until the antennae have actually come into contact with it. All millipedes
are perfectly harmless, and may be handled with impunity ; but those species
possessing odoriferous glands emit a disagreeable odour, due to the secretion of a
fluid containing prussic acid. This, no doubt, serves as a protection against birds,
ants, etc., to these otherwise defenceless creatures. Some birds will, however, eat
them ; and in a hornbill's nest in the British Museum the plaster used to block the
entrance is largely composed of crushed fragments of a large Spirostreptus. Many
of the species which have no glands are otherwise protected. Polyxenus, for instance,
is studded with bristles ; while the Oniscomorpha roll themselves up into a round
ball, with nothing but the horny integuments exposed. In the breeding-season the
females of several forms make earthen nests for their eggs, working the lumps

MILLIPEDES AND SCORPIONS.

213

together. The pill-millipede (Glomeris) is said to encase only a few eggs in a ball of
earth ; while lulus lays from sixty to a hundred in her nest before closing the
aperture. Among the suctorial millipedes it is said that the common European
Polyzonium germanicum coils round her cluster of eggs and stays by them
until they are hatched. When
hatched, the young are minute, pale-
coloured creatures, consisting of the
head, with its antennae and jaws, and
six body segments, of which the first
three are provided with a pair of legs
apiece. During growth the rest of
the segments are gradually added
between the fifth and sixth, the latter
remaining the terminal segment.
Growth is also accompanied by
moulting.

Remains of extinct millipedes,
referable to several of the existing
families, occur in the middle Tertiary
rocks, while one species of doubtful
position has been discovered in the
Cretaceous. In the Carboniferous and
Devonian rocks a number of types
apparently referable to the millipedes occur, although they have been assigned to
a special order. From the existing forms they differ by the incompleteness of
the union between the dorsal elements of each double segment.

Allied to the millipedes in many characters, but differing in certain special
features, is the small group known as Pauropoda. These contain some minute
creatures, found in earth and rubbish heaps in Europe and North America, and
remarkable for the fact that their antennae are branched at the apex, and furnished
with long bristles. These have twelve body segments, and only nine pairs of legs,
the first and the last two segments being limbless.

millipede OP the genus Spirostreptus, from Celebes.

Scorpions, Spiders, Ticks, etc, — Class Arachnida.

The members of the three classes of Arthropods hitherto considered are
characterised by the possession of a distinct head, bearing in front of the mouth a
pair of antennae, and at the sides of the same at least two pairs of appendages,
which act solely as jaws. In the scorpions, spiders, and their allies, on the other
hand, there is no such distinct head, while antennae are wanting ; the first pair of
appendages being composed of two or three segments only, and acting as seizing
or biting organs. These mandibles are, in fact, the only limbs that can be
described as jaws. It is true that the basal segments of the second, and sometimes
of the third and fourth, pairs of limbs are used for crushing prey; but their
remaining segments nearly always form leg-like appendages, used both for locomo-
tion and grasping. In scorpions, for instance, the limbs of the second pair are

214 SCORPIONS.

converted into large pincers; while in spiders they are short, and resemble the
other limbs. In scorpions and the other groups, where these limbs form prehensile
weapons, they are called chelce ; whereas in the spiders and ticks, where they are
smaller and tactile in nature, they are known as palpi. Behind the palpi or chelae
come four pairs of limbs, acting as the locomotor organs. The palpi or chelae are
typically composed of six segments, and armed with a single claw, which, however,
may be fused with the terminal segment, as in scorpions. The legs seem primarily
to have been six-jointed ; and their segments, from base to apex, are respectively
termed coxa, trochanter, femur, patella, tibia, tarsus. One or more of these is,
however, almost invariably divided, so that the number rises to at least seven.
Thus, whereas in the scorpions the tibia, and in spiders the tarsus, is divided, in
other groups, like the Pedipalpi, the tarsus may be composed of a number of small
segments. Accordingly, six pairs of large appendages are attached to the forepart
of the body ; and since this part was supposed to represent the combined head and
thorax of insects, it is termed the cephalothorax. The abdomen may bear small,
dwarfed limbs, as in scorpions and spiders, but its limbs are never, either structurally
or functionally, like those of the cephalothorax. Although it may be undivided,
this part never contains more than twelve segments, and often much fewer.
Allowing twelve to the abdomen, and six to the cephalothorax, the body of the
more typical members of the class comprises eighteen segments. All Arachnoids
breathe air, either by means of short sacs or of long tracheal tubes communicat-
ing with the exterior by apertures (stigmata) on the lower surface of some
of the abdominal segments. The young which, save in scorpions, are born in
the egg stage, resemble their parents, and in the course of growth only undergo
a series of moults without metamorphosis. The class may be divided into eight
orders, the first of which includes

The Scorpions, — Order Scorpiones.

In this group all the typical eighteen segments of the body are developed, although
the last five are abruptly narrowed to form with the telson, or poison-sting, the
tail. The whole abdomen, including the tail, is distinctly jointed ; but the cephalo-
thorax is covered above with a single plate, or carapace, bearing the eyes. The
latter vary from six to ten, two being placed together in the middle, and the others
arranged at the sides of the forepart of the carapace. Of the appendages, the
four hinder pairs are similar, being tipped with a pair of claws, and used for
locomotion. The two front pairs, however, have been transformed into pincers or
nippers, the first pair, or mandibles, being small and three-jointed, and the second,
the chelae, or great pincers, of large size and six-jointed. The coxae of the four
pairs of legs are immovably united to form the floor of the cephalothorax, and
wedged in between those of the last two pairs there is a single sternal plate, the
shape of which is of considerable value as a character in the classification of these
animals. The breathing-organs consist of four pairs of sacs, — of which the
cavities are filled up with a number of fine plates, arranged like the leaves of a
book, — are placed upon the third, fourth, fifth, and sixth segments of the abdomen,
and their apertures open upon the sternal or ventral plates of these segments.

SCORPIONS.

215

In addition to these stigmata, the abdomen bears a pair of curious organs called
combs, or pectines, which are placed upon the lower surface of the second segment,
and are very characteristic of the group.

Scorpions are found almost all over the world to the south of the 40th or
45th parallel of north latitude, the only extensive area of land in the Southern
Hemisphere in which they do not occur being New Zealand. The largest known
forms occur in the tropical parts of Africa, especially on the shores of the Gulf
of Guinea, and in the southern districts of India. These are the big black
scorpions belonging to the genus Scorpio, which may
attain a length of 8 or 9 inches, measured from the
front of the head to the end of the tail. In structure
the various species and genera are, on the whole,
surprisingly uniform, all the known forms being refer-
able to four families, namely, the Buthidce, Bothriuridce,
luridce, and Scorpionidce. In the Buthidce the sternum
of the cephalothorax is small and triangularly-pointed
in front, in the Bothriuridce it is transversely linear,
and in the others it is broad and pentagonal ; but while
the luridce agree with the other two families in pos-
sessing two spurs on the articular membrane of the
tarsus, the Scorpionidce have but one.

Scorpions are a very ancient group, well-preserved
remains of two genera having been discovered in the
upper Silurian beds of both Europe and North America.
In the Carboniferous period, too, they were evidently
abundant ; but no fossil forms have yet been discovered
in rocks of Secondary age, and only one has been recorded
from Tertiary strata, this having been discovered in the
amber beds of the Baltic. The strangest fact however,
connected with fossil scorpions is the small amount of change the group has under-
gone, in spite of the enormous time that it has been in existence. For instance, the
Tertiary species named Tityus eoccenus does not differ in any important particulars
from existing forms ; while those from the Carboniferous can only be distinguished
from them as a group by having the median eyes on the carapace in advance of
the lateral. In this feature they agree with the Silurian species ; but the latter,
of which Palceophonus is the best known, are unique in the entire group in
having the feet tipped with a single claw. For this reason the order, including
living and extinct species, has been divided into two sections, the Apoxypodes,
or those with pointed feet, including the Silurian Palceophonus, and the Diony-
chopodes, or those in which the feet are tipped with a pair of movable claws.
This last group is again divisible into the Anthracoscorpii, or scorpions of the
Coal period, in which the median eyes are in front of the lateral, and the
Neoscorpii, or recent forms, in which the median eyes are placed further back.

In habits the different species seem to vary but little, most of them being
nocturnal and all of them exclusively carnivorous, feeding upon any living creature,
weak enough to be overpowered. They seem, however, to be largely dependent

SPANISH YELLOW SCORPION, Bllthus

eurojpceus (nat. size).

a, Lower surface of the abdomen,

showing combs and stigmata.

2l6

SCOEPIONS.

upon chance for the capture of prey ; for although provided with a large number
of eyes, vision is so defective that they cannot see more than a few inches, and there
is no evidence of the existence of any organs of hearing. The sense of touch, how-
ever, which resides in the hairs with which the body and limbs are studded, is
exceedingly keen. No sooner does an unwary insect approach within reach than

it is seized in the vice-like grip of
the scorpion's pincers ; then quick
as lightning the tail is brought into
use, and the sting plunged into the
struggling prey, which, as a rule,
quickly succumbs to the paralysing
effect of the poison. If, however,
the prey be of large size, and
muscular in proportion, the process
of stinging is repeated ; but it has
been noticed that the scorpion in
most cases carefully selects a soft
spot into which to thrust its weapon,
and does not strike at random. The
object of this caution is evidently
to avoid all risk of breaking the
point of the sting against too hard
a substance. The same care is
shown in the carriage of the tail,
this organ when not in use being
almost always kept curled up in
such a manner that the sting is
securely protected. Having imper-
fectly developed visionary powers,
and no tactile antennae to supply
this deficiency, scorpions when on
the move always hold their large
pincers well to the front, so as
carefully to feel the way. But
different species show considerable
variation in the carriage of the
body, some like Buthus, holding it
high, while others shuffle along
scarcely lifting it off the ground.

Again, many of the larger
species, such as those belonging to
Scorpio and Opisthophthalmus, live in deep holes, which they excavate in the ground
by means of their large and powerful pincers. Others, like the little flat scorpions
of South Europe {Euscorpius), hide away under stones and tree trunks, to which
they cling belly uppermost ; whilst others, like Buthus, dig shallow pits in
sand, just deep enough to allow their eyes a clear vision of their surround-

african ROCK-SCORPION, Scorpio viatoris (nat size).

WHIP-SCORPIONS. 2 1 7

ings, with the back on a level with the surface of the soil, and here concealed
from view they lurk on the look out for prey. Sound-producing organs have
been found in the large, black rock-scorpions of India and Africa; the organ,
which lies between the basal segment of the pincers and that of the first pair
of legs, consists of a set of tubercles and of a cluster of curved hair-tipped spines.
When the scorpions are excited, they wave their pincers up and down, and by thus
scraping the spinules against the tubercles emit a rustling sound, which has been
compared to that produced by rubbing a stiff tooth-brush with one's finger nails.
This organ is equally well developed in members of both sexes, and probably serves
as a warning to enemies to keep their distance. An analogous organ is found in
the South African Opisthophthalmus, but in this case it consists of leaf-like
hairs placed on the inner surface of the mandibles.

The Whip-Scorpions and their Allies, — Order Pedipalpi.

The members of the second order of the Arachnida resemble the scorpions in
having the abdomen composed of twelve segments, and the second pair of append-
ages transformed into huge seizing organs, but differ from them in a number of
important characters. The legs of the first pair, for instance, are not used for
locomotion, but only as organs of touch, and have their last segment devoid of
claws and divided into a series of secondary segments. Moreover, in the rest of
the legs the feet are three-jointed. The most marked distinctions are, however,
found in the abdomen. In the first place, this region is sharply marked off from
the cephalothorax by a deep constriction forming a narrow waist. There is no
trace of combs, and the first sternal plate is of large size, and entirely covers the
ventral region of the first and second segments ; so that, although there are twelve
dorsal plates on this region of the body, there are only eleven sternal plates. The
breathing-organs are of the same nature as those of the scorpions, namely, lung-
books ; but instead of forming four pairs, situated upon the third, fourth, fifth, and
sixth sterna, there are only two pairs, of which the apertures are placed behind
the sterna of the second and third segments. The order is divided into a tailed
group (Uropygi), and a tailless group (Amblypygi). In the former the body is
elongate, both cephalothorax and abdomen being much longer than wide ; and to
the last segment of the abdomen there is attached a movable tail corresponding to
the sting of the scorpions. On the lower side of the cephalothorax there are two
distinct sternal pieces, an anterior and a posterior, the latter being triangular and
lying between the coxae of the last pair of legs, while the anterior is longer and
placed between the coxae of the first pair of legs and behind those of the pincers,
which are united to form a kind of lower lip. The area between these sternal
plates is narrow, membranous, and largely encroached upon by the coxae of the
second and third legs, which nearly or quite meet in the middle line. The legs
of the first pair are also much shorter, and more typically leg-like than in the
Amblypygi, the tarsal segment alone being divided into a series of nine cylindrical
secondary segments.

_ „ _ _ The tailed suborder may be further divided into the sections

Tailed Group. . J

Tartarides and Oxopoei. The former is a small group in which the

WHIP-SCORPIONS.

cephalothorax is divided into two regions by the jointing of the carapace, the
region which corresponds to the posterior two pairs of legs having a small but
distinct tergal plate of its own. Moreover, the eyes are either absent or reduced
to a single pair, and the tail-piece, which is jointed to the last segment of the
abdomen, is short and undivided. There is a single family of this tribe, the
Schizonotidce, so-called on account of the jointing of the carapace. The family
contains two genera, Schizonotus and Tripeltis, the species of which are pale-
coloured forms, less than quarter
of an inch in length, and con-
fined to Burma and Ceylon.

The term Oxopoei, or acid-
producers, is applied to the
family Thelyphonidce, or whip-
scorpions, which differ from the
last in having the carapace
undivided, and the tail long,
thread-like, and many jointed.
The last three segments of the
abdomen, too, are very narrow,
forming a movable stalk for the
filiform tail, and on its last
segment there are generally
two, sometimes four, clear yellow
spots, the ommatoids. The eyes
are always well developed, two
of them being situated close to
the front edge of the carapace,
and the others, of which there
are eight or ten, arranged in two
clusters of three or five each at
the sides of the head, some
distance behind the front eyes.
The adult males differ from the
females in having longer and
often differently shaped pincers,
and also very generally in
having the first ventral plate of
the abdomen larger and more swollen. The females of some genera (Thelyphonus,
Typopeltis), on the other hand, have the segments of the tarsus of the first pair
of legs peculiarly modified.

Considering their antiquity and wide range, the whip-scorpions are strikingly
uniform in structure. The largest specimens, measuring about 4 inches in length,
have been met with in North-East India and Central and South America. All
the species seem to be nocturnal, spending the day hiding beneath stones, logs of
wood, etc., and, when surprised, hurrying away with considerable speed into any
holes or crevices that are handy. The Indian species require moist surroundings,

female op bornean whip-scorpion, Thelyphonus hosci (nat. size).

WHIP-SCORPIONS.

219

Tailless Group.

being generally only found during the heaviest rains, and soon dying when removed
from their humid haunts. In Florida there is, however, a species frequenting dry
sandy localities; and some species dig burrows in the ground and use them as
permanent places of abode.

In the tailless group, or Amblypygi, the body is much flattened,
the carapace being wider than long, and kidney-shaped, and the
abdomen oval with the segments gradually decreasing in size in front and behind,
and none at the hinder end being narrowed to form a stalk. Corresponding with
the great width of the carapace, we find the coxae of the third and fourth pairs of
legs widely separated, so that there is an oval sternal area, around which the coxae
of the five pairs of large cephalothoracic limbs are arranged radially. The anterior

A west African tailless whip-scorpion, Titanodamen johnstoni (nat. size).

and posterior sternal pieces of the preceding suborder are present between the coxae of
the first and last pair of legs respectively, and the space between them is filled by
horny pieces, varying in the degree of their development. The appendages also
differ from those of the Uropygi, the basal segments of the pincers being freely
movable and not united together, while these appendages are longer, thinner, and
very spiny. The terminal segment forms a sharp claw, closing back on the pen-
ultimate segment like the blade of a knife. The legs of the first pair are long and
slender, and all its segments, except the first three, are converted into a long,
thread-like, many-jointed lash acting as a feeler. The males do not as a rule differ
strikingly in external characters from the females; although the abdomen is
narrower, and the pincers and legs are longer.

In geographical distribution the group resembles the Thelyphonidw, with the

2 2 o WEB-SPIDERS.

exception that it is spread over Africa south of the Sahara, extending from
Senegambia and Abyssinia southwards into Cape Colony ; but there are no species
from Madagascar. It also seems to extend in India farther to the west than do
the Thelyphonidce, since species occur at Bombay, and thence spread along the south
coast of Arabia from Muscat to Aden. In the Indian region the species are not so
numerous as the true whip-scorpions, and in the Philippines they seem confined to
caves, living permanently in the dark. None are known from Japan or China ; but
in America a few have been recorded from Texas and California, and many from
Central America, the West Indies, and South America, as far down as Patagonia.
Like the last, this group dates back to the Carboniferous, a single genus,
Grceophonus, having been described from the coal-measures of North America.
A single specimen has also been discovered in the Miocene gypsum beds of Aix.
The existing forms may be all included in the family Tarantulidce ; the genera
being mainly characterised by the degree of development of the horny pieces on
the lower surface of the cephalothorax. In habits the group resembles the last,
except that the species, instead of digging burrows, avail themselves of natural
crevices and holes, hiding beneath stones or fallen tree trunks, for which t\xey are
adapted by the flatness of their bodies. The species frequenting grottoes in the
Philippines cling to the walls, with legs extended, and dart into rocky fissures at
the least disturbance.

Order Palpigradi.

This group is represented only by a single South European form (Koenenia
mirabilis). Structurally, this minute creature occupies a position intermediate
between the whip-scorpions and the Solifugce. As in the Thelyphonidce, there is
a long, jointed tail, articulated to the last abdominal segment, which, with the two
that precede it, is narrowed to form a movable stalk ; but, as in the Solifugce,
the abdomen consists of only ten segments. The carapace is segmented and has
no eyes ; but in the structure of its appendages Kcenenia is peculiar. The
mandibles are large, pincer-like, and composed of three segments, but the palpi and
all the legs are alike, being long, slender, and composed of a number of segments.
The legs of the first pair, however, are the longest, as in the Pedipalpi.

The True or Web-Spiders, — Order Arane^e.

In many points of their organisation, the true spiders approach the tailless
Pedipalpi. They have, for instance, a deep waist, separating the cephalothorax
and the abdomen ; the limbs are arranged radially round the cephalothorax, which
is covered below by a single sternal plate, to which a labial piece is united in front,
and above by a carapace bearing, in the majority of cases, eight eyes. Moreover,
in some instances, there are four pairs of lung-sacs, as in the Pedipalpi, although
generally the hinder pair are replaced by tracheal tubes. The differences between
the two orders are, however, striking enough. Thus the four pairs of legs are.
alike, being composed of seven segments, and used for locomotion ; while there are
no great seizing limbs, the appendages of the second pair being short and leg-like,
though composed of but six segments ; of these the basal is termed the maxilla, on

WEB-SPIDERS.

account of its function as a jaw, and the remaining five the palpus. The mandibles,
too, are larger than in the Pedipalpi, and contain a poison-gland, opening at the tip
of the second segment, which is transformed into a strong fang. In the abdomen,
a marked character of most spiders is the absence of segmentation, its covering
consisting of a soft, hairy integument, or a hard horny cuticle, while on its
lower surface there are two pairs of shortened appendages, called the spinning
mammillae, upon which open the silk-glands. These mammillae are perhaps the
most distinctive feature in spiders. Although varying considerably in shape and
length, they are usually short and composed of two, or rarely three, segments. Each
spinning appendage, however, is primarily
composed of two branches, an outer and an
inner, the outer forming the two- or three-
jointed mammilla, while the inner branch
or intermediate mammilla is always one-
jointed. Consequently there may be as
many as eight mammillae ; usually, however,
there are but six, owing to the disappear-
ance of the inner branches of the first pair
of spinning appendages.

The oldest known form (Arthrolycosa)
of the Carboniferous, differs from nearly all
existing forms in having the abdomen pro-
tected above by a series of plates, as in the
recent genus Liphistius, to which it was
doubtless allied. In Tertiary times, spiders
closely related to those now existing were
abundantly distributed over the Northern
Hemisphere, as their well preserved remains
from the Oligocene amber beds of the Baltic
and from the gypsum beds of Aix satis-
factorily testify.

The females of all spiders lay eggs, from
which the young are subsequently hatched
laying, is to spin a small and often saucer - shaped web. In this the eggs are
deposited, and are then covered over with two layers of silk forming a cocoon. The
cocoons differ greatly in shape and colour and texture, according to the spider that
makes them. They may be green, yellow, white, mottled, or nearly black; round,
oval, lenticular, or cigar-shaped ; soft and woolly, hard and nut-like, or smooth
like parchment ; while the outer casing is sometimes caked with earth or other
foreign material for purposes of concealment. After the construction of the cocoon,
the mother's interest in its fate varies in different spiders. Sometimes she pays
no further attention to it, as in the case of the garden spider (Araneus), which
suspends it in or near her web, and leaves the young to shift for themselves.
In some cases, again, she remains for a longer or shorter time on guard in its
vicinity, sometimes spinning a regular nest for her young and herself during this
period of quiescence ; but in other cases, especially among the wandering species,

ANATOMY OF COMMON CROSS SPIDER (Araneus

diadema).
1, Foot with claws and hairs ; 2, Mandible with
poison-gland and duct ; 3, Face and jaws ; 4, Spin-
ning mammillae ; 5, One of the spinning papillae.

The first act of the mother before

222

WEB-SPIDERS.

FEMALE OF DrClSSUS LAYING
HER EGGS.

the mother carries the cocoon about with her, either attached to her spinners or
clasped between her jaws. The young hatch inside the cocoon, and subsequently
make their way to the outer world through a rupture in its walls. They appear
in a helpless state, either clinging together in clusters, as in the Argiopidce ; staying

in the nest, as in the jumping spiders ; or clambering
on to their mother's back, as in the wolf - spiders.
During growth the skin is periodically cast, the mem-
brane of the cephalothorax splitting above the base of
the limbs, and the carapace being raised to make an
aperture, through which the body with the new skin
emerges. The young spider is then soft, limp, and at
the mercy of its enemies, until the integument becomes
sufficiently hard and resisting to afford firm support
to the muscles. Consequently, during this time, many species seek shelter in
silken tubes spun for the purpose. On an average, perhaps, spiders undergo about
eight or ten moults before reaching maturity, which is attained during the period
intervening between the last moult and the last but one, so that the males and
females, which during growth are much alike, emerge from the final casting in a
fully developed state. In this stage the two sexes are distinguishable, the female
having the palpi normally constructed, while in the male the terminal segment
of this appendage carries on its lower surface an organ which in its simplest form
is somewhat flask-shaped, but is more
often variously modified and compli-
cated. The male, also, is generally
rather the smaller of the two, some-
times indeed, as in many tropical
members of the family Argiopidce,
being of quite insignificant size in
comparison with the female. He also
has longer legs and a thinner abdomen,
being thus the more graceful and
active of the two. In the most
sedentary of all spiders, or those
belonging to the families Theridiidce
and Argiopidce, still more striking
differences often occur, the front part

of the carapace being sometimes raised into a high pinnacle-like outgrowth. When
the two sexes are approximately equal in size, the male is comparatively safe from
his spouse during the period of courtship, but when, as in the Argiopidce, he is much
the weaker of the two, the female often avails herself of her superiority in size and
strength to devour her mate. The first uses of the silk-glands seem to be to supply
material for the construction of the cocoon, and of a tent or tubular retreat for
the protection of the mother and young, or for the latter when passing through
the dangers attendant upon the casting of the skin. Such cases are also used for
the same purpose by many species during the winter months in temperate latitudes,
and during drought in more tropical climes. It thus appears that, in the first

female of wolf-spider (Pardosa amentata) carrying

HER COCOON.

Below is shown the arrangement of the eyes when
seen from above.

WEB-SPIDERS.

223

instance, the spinning instincts were directed solely to the protection of the species
during infancy, growth, and maturity ; and we may conclude that, apart from the
cocoon, the initial stage in the development of web-making was the formation of
some kind of tubular retreat. From this point the evolution of the spinning
industry — perhaps the most important and interesting feature in the natural
history of spiders — seems to have progressed
along two lines. Along one the tubular retreat
becomes gradually elaborated until it culmin-
ates in the trap - door nest ; while along the
other the tube is to a greater or less extent, or
even wholly, superseded by a new structure,
the snare ; the latter attaining its greatest
perfection in the triangular snap - net of
Hyptiotes, or the beautiful and symmetrical
orb -web of the common garden spider. At
the outset it is possible that the simplest form
of snare arose from the spinning of supporting
lines around the mouth of the tubular retreat,
and if these served to entangle prey it is clear
that a new and easy method of obtaining food
would be opened up, and the habit of spinning
webs of this nature would be fostered until
the various kinds of nets became evolved.
Another use to which the spinning of threads
may be put is that of flying. This is especially
practised by young spiders, who on fine
autumnal days climb to the tops of bushes
and fences, and, raising the abdomen into the
air, emit a thread or tuft of threads which
blowing away in the wind soon become large

and strong enough to carry the spider, sometimes to great heights above the ground.
It was originally supposed that these threads were spun by a species called the
gossamer-spider, but it is now known that the habit is practised by young spiders
of different families. Floating about in the air, these fine threads meet and,
becoming entangled, form masses of web, which ultimately fall upon the bushes
and fields, sometimes covering them thickly with a white coating of fine silk.

Jamaica trap-door spider (Pachylomerus)

AND APERTURE OF ITS NEST.

Segmented Group, — Suborder Mesothelae.

Spiders may be divided into the two main groups, Mesothelce and Opisthothelce.
In the former, the spinning mammillae, eight in number, are situated in a cluster in
the middle of the lower surface of the abdomen ; the upper surface of the latter
being covered with a series of nine dorsal plates, resembling those of scorpions,
while its lower surface is similarly furnished with two sternal plates covering the
first and second pairs of lung-sacs. In these characters the group differs from other
spiders, and in having the abdomen segmented it constitutes a kind of link

224 WEB-SPIDERS.

between them and the tailless Pedipalpi. It likewise resembles the latter
in the structure and situation of the breathing-organs, and also in the mode in
which the mandibles are articulated to the cephalothorax ; their basal segments
being directed forwards, parallel to each other and the long axis of the body, while
the second segments or fangs are directed backwards, also nearly parallel to the
longitudinal axis. The eight eyes are situated on a tubercle close to the front
edge of the flat and broad carapace ; the median being small, and the lateral
larger and placed in a semicircle on each side. The long and powerful legs are
armed with spines, and tipped with three claws ; their coxae being long, whereas
those of the palpi have no long maxillary process as in most other spiders. This
group comprises only the family Liphistiidce, with the genus Liphistius, of which
there is one species from Penang, and another from Sumatra ; both of large size,
measuring about 2 inches in length. Nothing is known of their habits.

Typical Group, — Suborder Opisthothelse.

In this group the abdomen is not segmented, and the spinning mammillae — of
which there are never more than six, owing to the disappearance or fusion of the
inner branches of the first pair of appendages — have moved to the hinder extremity
of the abdomen. It is separable into the sections Mygalomorphce and Arach-
nomorphce. The former group includes the forms making the nearest approach
to the preceding suborder. The spinning mammillae are reduced in number, being
usually only four, owing to the disappearance of the anterior pair of appendages,
the posterior pair alone remaining, and being represented on each side by a long
external jointed branch and a short inner one-jointed branch. Sometimes, how-
ever, two mammillae of the front pair are retained. The eyes generally form a
compact group but the lateral eyes on each side may be widely separated from
the median pair.

Several families, passing almost imperceptibly into one another, are com-
prised in the group. Among these, the bird-catching spiders (Theraphosidce) are
the giants of the order. They include several genera, such as Avicularia and
Pcecilotheria ; a species of the latter being shown in the illustration on p. 225.
Usually they are dark brown or black in colour, and clothed with short hairs
mingled with bristles. The lower surfaces of the feet are covered with a thick
pad of silky hair, furnished with adhesive power, by means of which these spiders
are able to climb vertical sheets of glass. The claws on the feet seem to be of but
little service, being small and generally concealed amongst the hairs. There are
a large number of species and genera distributed over all tropical and subtropical
countries ; the largest species occurring in the northern parts of South America,
where specimens almost equalling a rat in size are met with. The males are always
smaller than the females, being of lighter build, longer in the leg, and consequently
more agile. These spiders spin no web for the capture of prey, living either in
holes in the ground or beneath stones and silk-lined logs, or in silken tubes which
they spin in the hollows or upon the forked branches of trees. At night they
issue forth in search of food which for the most part consists of beetles and
other insects; but they will destroy and eat any living creature weak

WEB-SPIDERS.

225

enough to be overpowered, and travellers report having found small birds in their
clutches. When laid, the eggs are wrapped in a strong cocoon, which the mother
guards in her nest.

The bird-eating spiders inhabiting the countries lying between India and
Queensland differ from those coming from Africa and America in possessing sound-
producing organs, which lie between the outer surface of the mandible and the
inner surface of the maxilla or basal segment of the palp. In one case, namely,
in the subfamily Selenocosmiince, the outer surface of the mandible is furnished
with spines, and the inner surface of the maxilla with a set of horny notes, of
varying thickness and length, which are thrown into a state of vibration by being

banded bird-eating spider (Pcecilotheria fasciata).

rubbed over the spikes on the mandible. This organ is equally well developed in
both males and females, and appears in the young soon after they emerge from
the eggs. When these spiders are irritated or alarmed, they raise themselves upon
their hind-legs and, by waving the palpi, scrape the keys against the spines on
the mandibles and produce a sound which has been described as resembling the
dropping of shot upon a plate. It is probable that the sound thus produced acts
for the benefit of the spider in warning other creatures. In the second group
(Omithoctonince) the notes, formed of feathery hairs, are situated on the outer
surface of the mandible, and the spines on the inner surface of the maxilla.

Nearly allied is the family Dipluridce, differing in having three well-developed
claws upon the feet, and the external spinning mammillae exceedingly long. Its
members differ in habits, spinning upon the ground wide sheet-like webs to ensnare

vol. vi. — 15

226 WEB-SPIDERS.

prey. So far as the claw armature of the feet is concerned this family leads on
to the trap-door spiders (Ctenlzldce), famed for the perfection of their architecture.
Although the species exhibit considerable variation in the perfection of their nests,
the method of work appears in all cases to be substantially the same. A deep
tunnel is first dug in the soil and then lined with silk to prevent the falling in of
the loose earth. Then, with the object of excluding enemies such as ants and wasps,
as well as to keep out rain, a lid, formed of layers of silk, strengthened with
particles of soil, is built over the aperture, and attached along one side to the wall
of the tube in such a manner that the elasticity of the silken hinge keeps the door

normally closed. The outer surface of the
door is then covered, if necessary, with
fragments of moss, or with pieces of the
plants that grow in the vicinity of the
nest, so that when the door is closed it
matches its surroundings and becomes
practically invisible. In the genus
Nemesia, from the shores of the Mediter-
ranean and abundant in the Riviera, the
lid is thin and light and of the so-called

PALM TRAP-DOOR SPIDER (Pseudldiops) AND ITS , ,„£„„ ±„„« . V«i J_ IL *i £ -i.

NEST (nat. sizeV Wa±er ^Pe ' but in the maJorlty <>f Cases it

is thick and heavy, with a bevelled edge, so
that it fits tightly into the upper end of the burrow, and is said to be of the cork-
type. Not unfrequently the spider digs a side gallery to this burrow, and shuts
the aperture of communication between the two by means of a second door. Then,
in cases of emergency, when the lid of the main entrance has been forced, the
spider retreats along the second branch and closes the door, so that the enemy,
after exploring the main tube and finding it empty, departs, believing the burrow
to be tenantless. In some instances, indeed, the secondary branch is made to
communicate by a special opening with the exterior, so that even if its internal
aperture be discovered, the spider can still beat a retreat. It is by no means,
however, an easy matter to force open the lid in the first instance ; for no sooner
does the spider feel the attempt being made, than it seizes the inner side of the
door with the claws of its front-legs, and, firmly planting those of its hinder limbs
in the silken walls of the burrow, resists every effort to force an entrance. A few
species have forsaken the ground and taken to building their nests upon the
trunks of trees, as shown in the figure above. Some of these, like the South
African Moggridgea, and the Mascarene Myrtale, avail themselves of natural
irregularities in the surface and build silken tubes in the crevices ; then, chipping
off pieces of bark and lichen, cover the white silk, so that the tube and its door
become invisible. The South American Pseudldiops, frequenting palm-trees at
Bahia, appears to excavate its own grooves in the bark by means of the fangs, and
the stout, short spines with which its mandibles are armed.

In North Europe the only representative of this group is the genus Atypus,
which has been found in England and Ireland. This genus belongs to the
family Atypidce, differing from the rest of the section in possessing long maxillary
processes on the coxae of the palp ; and also in having six spinning mammillae.

WEB-SPIDERS.

227

Instead of making a trap-door nest, this spider spins a long silk tube, closed at
the ends, one half of which is buried in the earth, while the other lies loosely
among the grass or stones on the surface of the ground. When a fly or beetle
alights on this part of the web, the spider slowly and cautiously climbs to the
spot, and, invisible all the time to the insect, suddenly seizes it from within, and
tearing away the web drags its prey through the aperture, which is then
repaired.

The next section is that of the Arachnomorphcv, which includes the common
house and field spiders, and differs from the last in having the basal segment of
the mandible vertical instead of horizontal, and the fang closing inwards and
backwards. There are generally six spinning mammillae, comprising an anterior
two-jointed pair, a similar posterior pair, and an intermediate single-jointed pair.
Between those of the front pair there is either a functionless membranous piece,
the colulus, or a paired plate, the cribellum, which is studded with the apertures of
spinning glands. The eyes are occasionally arranged in three clusters, two being
in the middle and three close together on each side ; but usually the three lateral

field-spiders (Segestria senoculata). a, Female ; b, Male ; c, Arrangement of eyes (enlarged),

ones are scattered, and the eight eyes placed on the front of the head in two rows.
The Arachnomorphce are divided according to their structural characteristics and
web-making instincts into a number of tribes each containing one or more families.
The first tribe, Umbellitelarice, contains the single family Hypochilidce, represented
by the genus Hypochilus in North America and Ectatosticta in China. These two
spiders differ from all the rest in having the hinder pair of breathing-organs in
the form of lung-sacs; the cribellum and calamistrum being present and the
long and slender legs furnished with three claws. In the genus Hypochilas,
which is found in the forests of Tennessee, the web is constructed beneath over-
hanging rocks and cliffs and has somewhat the form of an inverted saucer, made
of thick white silk and kept in place by a loose network of threads. Beneath this
web the spider remains upside down, and it has the habit, common to other species,
of violently shaking the web when alarmed. In the tribe Pseudoterritelarice,
as in the rest of the section, the breathing-organs of the hinder pair are in the
form of tubular trachea?, but their apertures are widely separated and situated
immediately behind those of the front pair. There is no cribellum nor
calamistrum, and the eyes are reduced in number, being usually six, but some-
times, as in Hops, only two. Two well-known European representatives of this
tribe constitute the genera Dysdera and Segestria. The former, found not

-28

WEB-SPIDERS,

uncommonly under stones in damp places, may be recognised by the coral-red
colour of its carapace, its bright yellow legs and pale grey abdomen. It makes
no snare, merely constructing a small silken case, which serves as a protection
to the mother and her eggs at the breeding-season. Segestria, on the contrary,
is much darker coloured, with a band of diamond-shaped spots upon the upper
side of the abdomen. It spins in holes in old walls a tubular nest, from whose
aperture threads which serve to intercept prey pass to surrounding objects. In
addition to these forms — which belong to the family Dysderidce — this tribe con-
tains the family Oonopidce, comprising small, slender-legged spiders, with a short
and high carapace, and the exotic family Caponiidce, the chief peculiarity of
which is the transformation of the front pair of lung-sacs into tubular tracheae —
a character in which this family is unique amongst spiders. The Filitelarice
contain the family Filistatidce and genus Filistata ; the latter being represented
by several species, none of which are British. They are small or medium-sized

P

HOUSE SPIDERS.

a, Male ; b, Female (nat. size) ; arrangement of eyes shown on left hand of figure,

species, easily recognised by the aggregation of the eight eyes upon a tubercle
placed near the front border of the carapace; and of sedentary habits, spinning an
extended web of white silk, in the form of an ill-defined tube.

To the Tubitelarice are referred a number of families, presenting great
variation both in structural features and instincts. The Drassidce, for instance,
spin no snare, but merely fabricate* a silken case for themselves and young at the
breeding-season, while others, like the Agalenidce, which include the house spider
(Tegenaria atrica), build a flat, sheet-like web, continuous at one extremity with a
tubular retreat in which the spider lurks. The spiders of this last group which
spin these sheet-like snares are furnished with three claws on each foot, and long
posterior spinning mammillae ; whereas the Drassidce and Clubionidce, which live
under stones, make no snare, and catch prey by chase or by lying in wait, have all
the spinning mammillae short, and only two claws on the feet. The above families
differ from the preceding tribes of Arachnomorphce in that the stigmata of the
posterior pair of breathing-organs are not only united in the middle line to form
a single aperture, but this has also, as a rule, moved to the end of the abdomen in
front of the spinning mammillae. In two of the families, however, these apertures,

WEB-SPIDERS.

229

although covered with a fold of the skin, are distinct from each other, and have
only migrated part of the distance over the lower surface of the abdomen. These
families, Desidcc and Argyronetidce, have three-clawed feet like the Agalenidce,
but instead of being snare-spinners, fabricate a silken case to serve as a receptacle
for their eggs and as a place of refuge. Both have an aquatic mode of life. The
first family is represented by the genus Desis, found on the coasts and coral-reefs
of the South African, Indo-Malayan, and Australian seas. At low water the
reefs and rocks upon which they live are uncovered ; but at the rising of the tide
the spiders retreat into holes and crannies, where they surround themselves with
a layer of silk strong enough to keep out water. They are good swimmers
and feed upon small fish, crustaceans, etc. The Argyronetidce live in fresh water,
and are represented only by the water-spider (Argyroneta aquatica), frequenting
ponds and ditches in the British Islands and other parts of Europe. Amongst the

water-spiders, with nests (enlarged).

waterweeds the water-spider spins a thimble or bell-shaped web, the aperture of
which opens downwards. Then, ascending to the surface and thrusting its
abdomen out of the water, it succeeds, by some process not clearly understood, in
enveloping the hinder part of its body in a film or bubble of air. Retaining this
bubble in position by means of its hinder pair of legs, the spider swims down to its
web, and inserting its abdomen into the aperture of the bell, sets free the bubble of
air, which rises to the upper part of the cavity of the web and replaces a certain
quantity of water. The spider then fetches down another bubble, and repeats the
process until the web is filled with air; it then has a water-tight chamber, in
which it can dwell till all the oxygen is consumed. Here the eggs are laid and
hatched. This spider lives on insects which it catches in the water, Belonging
to the family Agalenidce is the genus Agalena, of which a British species
{A. labyrinthica) is abundant in most districts, and spins a large sheet-like
web upon hedges and bushes. At its inner extremity the web ends in a tube
communicating at the back with the bush, into which the spider makes its
escape when pursued. This spider is exceedingly agile, running with great speed

23o WEB-SPIDERS.

either on the ground or the upper side of its web. It has an ingenious method of
overcoming insects like bees, with which it is afraid to come to close quarters,
when they have fallen into the web. Attaching a thread to a spot close at hand,
the spider runs in circles round and round its entangled prey, letting out the
thread as it goes and gradually enveloping the insect, and effectually putting a
stop to all struggles. Then, when it is tightly bound, the spider cautiously
approaches, and, inflicting a bite upon the insect, puts an end to its life. Also
belonging to this family is the so-called cardinal spider (Tegenaria guyonii),
erroneously believed peculiar to the chapel at Hampton Co'urt. Although none
of the families of Tubitelarice hitherto considered possess the cribellum and
calamistrum, one family {Amavurobiidce) is supplied with these organs. A well-
known form is Amaurobius similis, which lives in holes in walls and ivy, where
it spins an irregular, untidy, woolly web. The Plagitelarice contain the family
Pholcidce, of which the genus Pholcus is the best known ; one species (P. phalan-
gioides) being not uncommon in the South of England, where in sheds and
outhouses it spins a characteristic web, composed of a tangled mass of irregularly
interlacing threads. This species has exceedingly long and slender legs, which at
first sight give it a close resemblance to the harvest spiders. It moves slowly and
clumsily ; but when alarmed has a habit of hanging downwards in the web, by the
tips of the toes, and swinging the body round and round with such rapidity that it
becomes almost invisible. No nest is made, and the cocoon consists of a flimsy
network, enveloping the eggs, which the mother carries about in her mandibles.

The next tribe — {Retitelarice) — contains a host of spiders belonging to the
families Theridiidce and Linyphiidce, most of which are of small size, while
gome are the smallest of all spiders. In structure they approach very near those
Tubitelarice which have no cribellum. The web consists of an irregular network
of lines, or a horizontal sheet of silk, but there is no tubular retreat ; and the
spider crawls along the under instead of the upper surface of the web. The cocoon
is suspended in or near the snare, and no nest is built for its reception. Of
the first family a well-known representative is Laihrodectv.s tredecim-
guttatus, which somewhat exceeds the common garden grass-spider in size, and
is either black or variegated with thirteen pale spots. Occurring in the countries
bordering the Mediterranean, this spider spreads it webs over grass fields, and lives
largely on grasshoppers. This species and others of the genus are much dreaded on
account of their poisonous bite. The Orbitelarice, or orb-spinners, containing the
best known of all spiders, are closely allied to the Retitelarice, from which they
differ by the presence of a smooth spot upon the base of the mandible, and also by
having a narrow space between the eyes and the base of the mandible. In this
group the art of net-spinning has reached its highest point ; all their claws on
the feet being highly developed, while some of the hairs on the apex of the
tarsi are barbed and toothed to form a kind of spurious claw. Such members
of the tribe as possess a cribellum and calamistrum, belong to the family
Uloboriclce, which contains the well-known European genera, Uloborus and
Hyptiotes. Both these spiders are adepts at the art of concealment ; the
former spins a shabby orb -web in a hollow tree trunk and places of a
like nature, and leaves in its web the debris of insects that have been

WEB-SPIDERS.

231

captured. It slings up, moreover, a string of cocoons, extending across the web,
and at one extremity of the line, or amongst the dried carcases of flies, the
spider takes its stand and harmonises so well in shape and colour with its surround-
ings as to be practically indistinguishable amongst them. Even more interesting
is Hyptiotes, which frequents pine trees, and is
a small thick-set little species almost invisible
on the bark. It spins a web, triangular in out-
line, with anchoring threads passing from each
of the angles to surrounding objects, and the
triangular space filled in with cross-lines running
parallel to the shortest side, and traversed in
the middle by a single thread running from the
apex to the base opposite. Taking up its position
on the long anchoring thread which passes from
the apical angle, and close to its point of attach-
ment to the branch, the spider pulls in the
thread so as to draw the whole net taut, coiling
up the slack line between its front and hind-legs.
The instant a fly strikes the net, the spider
loosens its hold of the line, when the snare
springs forward with a jerk, still further entang-
ling the prey by bringing other threads into
contact with it. If necessary, the net is snapped
more than once, and when the spider feels that
the insect is enveloped, it crawls leisurely along
the web to devour it. The genus is common to
Europe and North America. The other members

of this tribe belonging to the family Argiopidce have no cribellum nor calamistrum.
Their webs vary in form, but are mostly of the orb type, consisting of straight
threads radiating from a centre to the foundation lines, which are stretched from

one point of support to another, and of a spiral line
passing from the centre to the circumference, affording
support to the radial lines and partly filling in the
spaces between them. The spiral line is the principal
part of the web involved in the capture of insects, many
of its strands being covered with a series of gummy
drops like beads on a string, which greatly hamper the
movements of a captured insect. The presence and
position of an insect in the web is perceived solely by
the delicate sense of touch in the spider's feet, and for
this reason the spider either takes up its stand in the
centre of the web, where its eight legs can command all
the radii, or else beneath some leaf at the end of a long
thread passing from the centre to its place of concealment. In cases of danger the
spiders either drop to the ground by a thread, or, seizing the web with the tips of
their feet, start spinning the body round and round in circles and causing the web

an orb-spinner (Tetragnatha extensa) at

REST IN ITS SNARE.

Arrangement of eyes shown above.

common cross spider, Araneus
diadema (nat. size).

232

WEB-SPIDERS.

a side-walking spider (Xysticus viaticus). Female, left-hand figure : male,
right-hand figure (enlarged).

to oscillate rapidly until it and its occupant almost disappear from view. The
commonest British members of the family belong to the genus Araneus, of which
the cross or garden spider (A. diadema) is so abundant in gardens late in summer
and autumn. Some of the tropical forms, such as Nephila, are of enormous size,
and construct huge webs strong enough, it is said, to arrest the flight of small birds.
The males are veritable pigmies, as compared with the females. Also belonging to
the family are those curious tropical spiders of the genus Gastracantha, which are
protected from enemies by having the integument of the abdomen hard, horny,
and armed with spines. The figure on p. 231 of a species of Tetragnatha re-
presents another toler-
ably common member
of this family. It is
characterised by its lon£
and slender abdomen,
and enormousty strong
projecting mandibles.

We now come to
spiders differing from
nearly all the preced-
ing in that they obtain
their prey by hunting
instead of constructing
snares. The first tribe
of these, the Laterigradce, derives its name from the fact that its members walk with
a side, crab-like gait, a power which they owe to the rotation of their legs back-
wards in such a manner that the lower surface is turned forwards and the front
upwards. The two first pairs of legs are longer and stronger than the others ; the
tarsi have but two claws, and the eyes are arranged in a double row. Of the
families the so-called crab-spiders (Thomisidce) include small squat-looking forms,
with the two hinder pairs of legs weaker than the two front pairs. The carapace
is broad and often biangulate in front, and the abdomen frequently wider behind
than in front. These spiders are mostly sluggish and noticeable for their protective
coloration. Those frequenting flowers for the purpose of seizing the insects
that visit them possess the power of changing their tints to suit that of the blossom
in which they take up their abode. The egg-cocoon is sometimes rolled in a leaf,
sometimes left uncovered ; but after constructing it the female forsakes her
wandering life to watch over her offspring. The Heteropodidce differ in having
the mandibles more strongly toothed. The family is represented in Europe by a
few spiders of medium size (Sparassus, etc.), but in the tropics by many of large
size. One of the best known is the tropical house spider (Heteropoda venatoria),
a large, long-legged species, introduced almost all over the hotter parts of the
world. The female carries her lenticular cocoon tucked to the lower surface of
the cephalothorax. The annexed figure of a South African spider (Palystes)
shows the characteristic size and structure of the members of this family.

Passing over certain unimportant groups, we reach the running spiders,
Citigradce, which live on the ground, and capture prey by speed of foot.

WEB-SPIDERS.

233

south African side-walking sfider, Palystes (nat. size).

The legs are strong, not very unequal in length, and armed with three claws ; the

carapace is high, with the head compressed, and bearing on each side two pairs of

large eyes belonging to the hinder row, and in front the four smaller eyes of the

first row in a straight or

curved line. The typical

members of the tribe belong

to the family Lycosidce, or

wolf - spiders, of which a

number of small forms are

found in England, and the

north and central parts of

Europe. In summer these

may be seen darting swiftly

about amongst stones and

grass, the female often carry-
ing her cocoon attached to

her spinning mammillae.

This cocoon is a spherical

or more or less compressed

sac, consisting of an upper

and lower plate, fastened at

the edges. The mother

defends her packet of eggs with the utmost courage, and searches for it with

diligence if lost. Soon after hatching, the young emerge from the cocoon, and

climbing on to their mothers back cling there by means of silk threads, until

strong enough to shift for them-
selves. The smaller species
take refuge under stones or in
crevices, and form no retreat ;
but many of the larger,
especially those commonly
known as Tarantula in South
Europe, dig a burrow in the
earth, lining it with silk, and
in some cases building round
the aperture a low circular wall
of twigs or grass. To dig the
burrow, the spider first loosens
the earth with its mandibles,
then gathering the pieces into
a heap and sticking them
together by means of silk and
slimy matter secreted from the
mouth, with a rapid flick jerks

the pellet to some distance from the scene of its operations. At the entrance of

the burrow the spider lurks on the look-out for passing insects, and during the

Italian tarantula spider, Lycosa tarantula (nat. size).

234 WEB-SPIDERS.

winter covers up the aperture with silk and retires to the deeper parts to
hibernate. In certain districts in the south of Europe these Lycosidoe are dreaded
by the peasants, and fabulous accounts were given of the deleterious effects of
their poison. The bite was said to be the cause of a disease of an epileptic
nature called tarantism, and this could only be cured by music of certain
kinds, which worked the sufferer up to a state of frenzy. Another family
(Pisanridce) differs in having the eyes of the front row separated by a wide space
from the base of the mandibles. In this group Pisaura mirabilis is a common
British spider, living in woods and fields, and at the breeding season constructing
amongst grass or shrubs a large nest, open at the bottom. In this she lays her
eggs, enveloping them in a thick cocoon which is carried about in her mandibles ;
but when the eggs are hatched, she retires to the nest and remains there with her
young. The raft-spider (Dolomedes fimbriatus) is a large and handsome species,
frequenting the borders of lakes and marshes, and owing its name to its habit of
constructing a raft of leaves upon which it floats on the surface of the water. It can
run with speed upon the water, and does not hesitate to plunge beneath the surface
or run along the submerged stems of aquatic plants in chase of prey. The mother
carries her cocoon in her mandibles ; but at the time of hatching fastens it to some
plant near the edge of the water.

The tribe Saltigradce, or jumping spiders, contains the family Attidce, all of
which are of small or medium size, with a broad square head upon which the eyes

are arranged somewhat as
in the Lycosidoe; the
anterior four being set in a
straight line upon the front
of the face, while the
middle pair are of enormous

/o 9\ ^^ir 1|m s*ze* ^ne ^eSs are stout,

/ o j O \ £&■ Jp % %. rather short, and, a rare

thing in spiders, the third
jumping spiders {Epiblemum scenicum). a, Female ; b, Male ; Igcy is often the longest '

c, Female (uat. size) ; d, Arrangement of eyes. , , , , n

there are only two claws,
the place of the lower claw
being occupied by hair-tufts. For moulting, hibernation, and egg-laying, the jumping
spiders spin a small saccular nest, which in the latter case is frequently open at one
or both ends. In this the eggs are laid and hatched, and the young remain for some
time under their mother's protection. Certain species depart from the normal type
of structure of the others and closely resemble ants. This is brought about by the
globular form of the abdomen, and a sharp constriction in the hinder half of the
cephalothorax, so that the body appears to be divisible into three parts, as in an insect.
Moreover, these spiders have learnt to walk with the gait of an ant, holding up a pair
of its legs to simulate the antennae. Thus disguised, they live in the company of
ants, and avoid the persecution to which they would be subjected if their identity
were not concealed. Why the ants refrain from destroying them is unknown.
These spiders spin no snare, and are dependent upon agility and great keenness of
vision for the capture of prey. Sighting an insect at a distance, and eagerly

FALSE SPIDERS. 235

watching the while its everjr movement, the spider gradually stalks nearer, until
within reach of a leap ; then, with a well-judged spring, launches itself on to its
prey, and, in spite of vehement struggles, tenaciously retains its hold until the
victim succumbs to the paralysing effects of the poison. An Australian species
(Attus volans) has acquired the power of prolonging its leaps into short flights,
by elevating flaps of skin which arise from the abdomen.

The False Spiders, — Order Solifug^e.

The members of this group bear such a strong superficial resemblance to the
true spiders that they are usually called by that name. The structural distinctions
between the two orders are, however, so great and so easily ascertainable, that an
example of the one may be without difficulty distinguished from an example of the
other. In the first place, the abdomen is composed of ten distinct segments, and
is not supplied with spinning-glands, while the breathing-organs, which are in the
form of long tracheal tubes, open upon its second, third, and sometimes on its
fourth sterna. The cephalothorax is distinctly jointed, its last two segments
having separate tergal plates, while its front part is covered by a head-shield
bearing a pair of large eyes near the middle of its front border, and merely traces
of the lateral eyes at the sides. The mandibles, which form a powerful pair of
toothed nippers, are articulated to the sides of the head-plate. The appendages of
the second pair are palpiform and tipped with a sensory organ ; but their basal
segments, like those of the legs, are united together on the lower surface of the
cephalothorax, which has no sternum. The three posterior pairs of legs are
tipped with two claws each, but those of the first pair have only a single minute
claw. On the basal segments of the last pair are certain racket-shaped organs,
termed malleoli ; and behind those of the second pair open a couple of large stigmata,
leading into additional breathing-tubes. The mouth is situated at the tip of a
long horny beak, projecting forwards between the mandibles. The males are
smaller and lighter than the females, but have more powerful and longer legs and
palpi. Their mandibles, however, are much weaker, and are furnished above with
a sensory organ called the flagellum. In both sexes the mandibles are supplied
on their inner adjacent surface with a set of ridges, which give rise to a grating
sound when rubbed together. Both in Europe, Africa, and America, the Solifugm
closely follow the scorpions in their distribution, ranging in America from the
Southern States of the Union southwards into Chili, and being found over the whole
of Africa ; none, however, have been recorded from Madagascar. In Europe they
occur in Spain, Greece, and South Russia, being abundant and of large size in the
steppes of the latter country. Thence they spread southwards and eastwards over
the desert countries of South- Western Asia and India ; but to the east of this
point they become gradually scarcer, and although species have been discovered
in Siam and the Moluccas, the group appears to be unrepresented in Australia and
New Zealand. No extinct members have been described.

The order contains but a single family Soljiugidce, divisible into several well-
marked genera, differing from each other in a number of structural characters.
The largest members of the group belong to the genus Solpuga, confined to South

236

FALSE SPIDERS.

Africa, and to Galeodes, which occurs in great numbers in Persia, Arabia, Egypt,
and South Russia. Another well-known form is Rhax, having the same range as
Galeodes, but being a smaller and shorter-legged type. In habits the false spiders

male of Persian false spider, Galeodes (nat. size).

are both diurnal and nocturnal; specimens of Galeodes and Rhax roam about
deserts at night, and, attracted by the light, make their way into the tents of
travellers, while at other times they may be met with darting about in the blazing

FALSE SCORPIONS. 237

mid-day sun. Most species of Solpugidce are extremely active, running with great
speed ; but those of Rhax — which have enormous mandibles and short thick legs —
are slow movers, and it is probable that the equally short-legged South African
Hexisopus is also relatively sluggish. When on the prowl, these creatures carry
the body raised high on the posterior six legs, those of the first pair and the palpi
being lifted up and waved in the air to feel the way, while the movements of
the head from side to side bear witness to their eagerness to discover prey.
Many stories are told of the courage and voracity of these animals. Their food
seems to consist mostly of beetles or other insects ; but they will not hesitate
to attack such redoubtable adversaries as scorpions.

The False Scorpions,— Order Pseudoscorpiones.

The false scorpions are all of minute size, the largest not exceeding a quarter
of an inch in length. They owe their name to the fact that, as in the true
scorpions, the appendages of the second pair are of enormous size as compared with
the body, and form pincers; the mandibles being small, and also pincer-like, while
all the legs are of the ordinary locomotor type. There is, moreover, no waist
separating the thorax from the abdomen, and the latter is distinctly jointed. All
these characters impart a considerable superficial likeness to scorpions, and
formerly the two groups were looked upon as closely allied, although there are in
reality many important, deep-seated differences between them. The abdomen, for
instance, in the Pseudoscorpiones, is practically the same width throughout, none of
the posterior segments being narrowed to form a tail, and
the last bears no skeletal piece at all comparable to the
scorpion's sting. The breathing - organs in the false
scorpions are structurally of the same nature as those of
the Solifugce, consisting of tracheal tubes, which open by
two pairs of stigmata, situated upon the third and fourth
abdominal segments. Like the true spiders, the false
scorpions possess silk-glands, but these are situated, not in B00K SC0RPI0^Wer can.
the abdomen, but in the cephalothorax, and open by croides (much enlarged).
minute apertures at the tip of the movable fingers of the

mandibles. In addition to these glands, there are others in the abdomen termed
cement-glands, which open upon the second and third sternal plates. The function
of these is not known, but' it has been suggested that they may secrete the gummy
material whieh causes the eggs to adhere together. The eyes, either two or four
in number, are placed on the sides of the forepart of the head-region.

The false scorpions, which occur in all temperate and tropical countries, live
for the most part under stones and the bark of trees, or hidden in moss or vegetable
rubbish ; only two European species, namely, Chelifer cancroides and Chiridium
museorum, are commonly found in human dwellings, in dark corners and the
wainscoting of rooms, in herbaria, or even in boxes of insect collections. Under
these conditions the former is but rarely met with, but large numbers have been
taken together in old bee-hives, wasp-nests, and badly kept pigeon-houses. The
two species, however, are by no means found exclusively in habitats of this nature,

238 HARVEST SPIDERS.

both having been observed under the bark of trees, far from the abodes of men.
In South America it is by no means uncommon to find species of Chelifer living
beneath the elytra of the large longicorn beetles. Some species frequent caves and
grottoes, and many of these, from dwelling permanently in the dark, have lost all
trace of eyes. Lastly, there are others which occur exclusively upon the seashore.
Gary pus littoralis, for instance — the giant of the order, so far as Europe is concerned
— being found in Spain and Corsica at the foot of the cliffs and beneath seaweed,
while, on the south coast of England Obisium maritimum may be met with under
the same conditions. The Cheliferida^ are, for the most part, slow in their move-
ments, walking with the pincers extended to feel the way, although they also
progress with facility sideways or backwards. The Obisiidw, on the contrary, are
much more agile, darting backwards with great speed when alarmed. Some
species of the genus Chithonius, indeed, are said to possess leaping powers of no
mean order.

Although possessing silk-glands, the false scorpions have not learnt the art of
ensnaring prey after the manner of spiders. They merely use the silk for con-
structing a small oval or spherical protective cell at the time of egg-laying, or for
purposes of hibernation, or moulting. A species of Chelifer has been observed to
build a cell, in the first instance, when preparing to moult, and in this receptacle it
stayed for five days, until the new integument had acquired its normal strength.
But about three months afterwards it returned to the same quarters to spend the
winter. As a rule these cells, or cocoons, are left uncovered, attached to the under
sides of stones, etc., but the Alpine Obisium jugorum covers its case with pieces
of earth and of vegetable debris. Like the majority of the class, false scorpions
are oviparous ; the number of eggs rarely exceeding fifty, although these are of
relatively large size. By means of a gummy material, the eggs stick together into
a rounded or oval mass, which remains adhering to the ventral surface of the
abdomen of the female. The young stay with their parent until they have
acquired their definite form, but, when first hatched, show no signs of segmenta-
tion, either of the body or limbs, and the abdomen, which is folded against the
lower surface of the cephalothorax, bears rudiments of four pairs of appendages,
which subsequently disappear. The only fossil remains of the group hitherto
discovered occur in the Tertiary amber beds of the Baltic ; the species being
apparently generically identical with those existing at the present time.

The Harvest Spiders, — Order Opiliones.

Although the members of this group are frequently confounded with the true
spiders, yet, as in the case of the scorpions and false scorpions, the resemblances
between the harvest spiders and the true spiders are comparatively few and
superficial, while the distinctive characters are many and deep-seated. In the first
place, the body is oval, and the abdomen, which is united throughout its length
with the cephalothorax, is, as in the scorpions and false scorpions, composed of from
three to eight segments. The carapace which is short, unjointed, and usually bears
one pair of eyes, is sometimes fused with the anterior segments of the abdomen ;
while in some cases the dorsal plates of all the abdominal segments are united to

HARVEST SPIDERS.

239

one another and to the carapace to form a single large plate, its separate elements
being merely defined \>y shallow grooves. The lower surface of the carapace is
either almost wholly covered by a forward prolongation of the sterna of the
anterior abdominal segments, or by the ingrowth of the coxae of the appendages.
The mandibles are composed of three segments, and are always pincer-like, and
sometimes very powerfully developed. The appendages of the second pair
(maxilla and palpus) consist of six segments, and are never chelate, although in
some species they are armed with spines, and the claw is much enlarged and capable
of being folded back upon the tarsus. In these species the appendage is used as an
organ of attack and
defence. The four
pairs of legs are alike
in form and function,
being used for loco-
motion. In addition
to the mandibles and
maxillae, there are
often accessory
mouth - parts, taking
the , form of masti-
cating lobes on the
maxillae and the coxae
of the first and second
pairs of legs; while
above the mouth
there is frequently a
labrum, or upper lip,
and above this a
second piece, or
clypeus. As in false
scorpions, breathing
is effected by means
of tracheal tubes,
opening by a pair of
orifices situated on
the sternal plate of

'the abdomen, immediately behind the coxae of the first pair of legs. In addition
to these stigmata, there is one on each side of the cephalothorax lying below the
edge of the carapace and above the coxae of the first pair of legs. These were
originally regarded as the apertures of breathing - organs, but it is now known
that they lead into glands, probably secreting an odorous and repellent fluid. In
some species of harvest spiders, the males and females are almost exactly alike ;
but usually the two sexes are recognisable by sharply marked characters. In the
males, for instance, the body is smaller and often more brightly coloured, while the
legs are both longer and more strongly spined, some of their segments being often
modified in shape. The greatest modification, however, is found in the mandibles,

south American harvest spider, Gonyleptes spinipes (nat. size).

240

HARVEST SPIDERS.

which are often much enlarged ; in the male of Phalangium opilio, for example,
the second segment is produced upwards into a great horn -like process. Fossil
forms occur in the Carboniferous, one of which has been described as Eophrynus.

Suborder Laniatores.

In the harvest spiders of this group the first sternal plates of the abdomen do
not project forwards to any great distance between the coxse of the cephalothoracic
limbs ; the first being thus separated from the mouth by a long though narrow
sternal area lying longitudinally between the coxae of the right and left sides. The
claw of the palpi is usually long, strong, and folded backwards against the tarsus,
while the other segments are generally furnished with strong spines. Only the

last four segments of the abdomen are free, the
anterior coalescing with the carapace, which bears
a pair of eyes, situated usually upon a single dorsal
tubercle. This suborder is represented by numerous
families in the tropical countries of both Eastern
and Western Hemispheres. South of the Equator
it extends to a considerable distance, reaching in
South America as far as Tierra del Fuego ; although
in temperate lands to the north of the Equator
it is poorly represented, there being only a few
species of small size in Europe and the United
States. In the tropical parts of Central and South
America the group attains its maximum of develop-
ment, both as regards species and genera, and the
abundance and size of individuals. In the families
Cosmetidce and Gonylcptidoe, for instance, speci-
mens sometimes reach an inch in length, and cover
with their long slender legs a span of many
inches. The suborder also has representatives in South Africa and Tropical Asia.

An aberrant group of the Laniatores is the family Sironidce containing a few
species from South Europe and the Oriental countries. These are all of small size
with elongate oval bodies, and relatively short and stout legs. The palpi, moreover,
are not armed with spines, thus resembling those of the following suborder; and
the legs are tipped with a single claw. The two eyes, which are situated at the
sides of the carapace, are raised on stalks, and generally there is an additional eye
on each side at the base of the stalk.

CHILIAN HARVEST SPIDER,

Gonyleptes chilensis (nat. size).

Suborder Palpatores,

These harvest-spiders differ from the preceding group in having the anterior
sternal areas of the abdomen thrust far forwards between the bases of the
thoracic limbs, so as to lie just behind the mouth. The claw of the palpi is short
and weak, and these appendages are small and unspined, being used merely as
organs of touch and not of prehension. The legs, moreover, are furnished with a

MITES AND TICKS. 241

single claw. This group has a more extensive range than the last, being repre-
sented by a number of forms in Central and South Europe, and extending even to
the Arctic Circle. The best known family is the Phalangiidw, which is exceed-
ingly rich in genera and species, and appears to be almost cosmopolitan in
distribution. The body is often soft-skinned, small, and sometimes almost of the
size and shape of a pea, while the legs, on the contrary, are exceedingly long and
slender, and even thread-like. Still more curious are the members of the family
Trogulidce, in which the integument is hard and thick, while the legs are short
and stout, and the front part of the head is produced forwards on each side into
a distinct plate, meeting its fellow of the opposite side to form a hood, hollowed
out below, and concealing the jaws and mouth-parts.

Group Ricinulei.

Tacked on to the Opiliones is a small group termed Ricinulei, which differs
in many important characters from the harvest-spiders. The mandibles, for
instance, consist of only two segments, and the palpi of only four (five with the
maxilla). Moreover, the anterior part of the carapace is furnished with a movable
hood, or cucullus, completely concealing the mouth ; and the abdomen consists of
only five segments. The legs are short, stout, and have two minute claws.

Considering the differences in structure presented by the various groups of
Opiliones, it is not surprising that corresponding differences occur with respect to
habits. The species with short, stout legs, and relatively heavy bodies, like
Trogulus and Stylocellus, are very sluggish, Trogulus lifting its legs one at a time,
and with apparent effort, and at the slightest danger ceasing all movement. This
immobility, coupled with the protective covering of earth that adheres to its
integument, conduces to the creature's safety by enabling it to escape observation.
The Palpatores and Laniatores, with their long slender legs and light bodies,
are much more active, and run off with speed when alarmed. Apart from the
agility which it confers, the extreme length of limb possessed by these Phalangiidce
stands them in good stead by enabling them to stand on tiptoe and out of reach
when threatened with destruction from armies of ants, which in tropical countries
kill and devour every creature small enough to be overcome by numbers.

The Mites and Ticks, — Order Acari.

The mites and ticks constitute a group which, for diversity of structure,
number of species and individuals, and minuteness of size, has no equal in the class.
Many are wholly parasitic in habit, and have become so profoundly modified in
organisation, and their affinities with the rest of the Arachnida so masked by
degeneration, that some authors have proposed to remove the Acari into a class by
themselves. Nevertheless, most of the species which lead a free life and have
departed least from the type of structure characteristic of the Arachnida, show so
many points of resemblance to the Opiliones, that it is by no means easy to draw
a hard-and-fast line between them. One leading character, however, by which the
ticks may be distinguished from the Opiliones is that the abdomen never presents

vol. vi. — 16

242

MITES AND TICKS.

any trace of segmentation ; it is confluent with the cephalothorax, the fusion between
the two being so complete, that, as in the harvest-spiders of the group Palpatores,
the anterior sternal plates of the abdomen are thrust far forward between the
coxae of the cephalothoracic limbs. As in all Arachnida, the mouth is adapted for
sucking, but the jaws are often partially united, and form, with a plate termed
the epistome, and the labium, a beak. The epistome is often of large size, and is
attached to the front border of the carapace ; the mandibles are either pincer-like
or simply pointed at the tip, forming piercing organs. The palpi, which resemble
a pair of small legs, have their basal segments, or maxillae, united together and to
the labium, to form a conspicuous plate or hypostome, constituting the floor of the
mouth. These organs forming the mouth-parts are often separated from the rest
of the cephalothorax by a membranous joint, and constitute a kind of movable
head, the capitulum. In many cases there are no traces of special respiratory
organs, breathing being effected by means of the skin ; but, when present, such
organs take the form of tracheal tubes, the apertures of which vary in position.
They may, for instance, lie in the head between the mandibles and palpi, or far
back in the body at the base of the legs of the last pair; but in some species
they occupy intermediate positions, and open in front either of the first, second,
or third legs. Another character of some value 'in separating the ticks from the
harvest-spiders, is that in the former the young undergo a metamorphosis in the
course of growth, being hatched from the egg as six-footed larvae, which later
acquire the fourth pair of legs. The order may be divided into the typical mites
and ticks (Acarina), and an aberrant worm-like group (Vermiformia).

The Acarina include a number of families severally distinguished by the
position of the respiratory stigmata, and the form of the mandibles and palpi. In
the velvety mites (Trombidiidw) the integument is soft and covered with variously
coloured hairs ; the legs are adapted for walking or running, the mandibles are

pointed at the tip, and the stigmata open in the
anterior portion of the body. There is usually
a pair of eyes on the carapace, although these
may be wanting. These mites, which may be
either parasitic or leading a free life, feed by
sucking the juices of animals or plants. A
fairly common British species is Trombidium
holosericeum, the second name referring to the
clothing of crimson silky hairs covering its body.
In the six -footed larval stage these mites live
parasitically upon harvest-spiders, to which they
cling, and resemble a cluster of bright red beads.
Before attaining maturity they fall from their
host to the ground, where, after undergoing their
final moult, they lead a free wandering life, living
upon minute insects such as aphides. In tropical countries mites of this genus reach
a large size, measuring half an inch in length. They are beautiful and striking
objects, resembling tufts of bright blood- red plush.

Nearly allied are the spinning-mites {Tetranychidce), which live exclusively

velvety mite, Trombidium holosericeum,
from below (enlarged eight times ; nat.
size on the leaf).

MITES AND, TICKS.

243

Right-hand figure, water-mite (Atax spinipes),
seen from below ; Left - hand figure.

WATER-SCORPION, INFESTED WITH A tax.

upon plants, and obtain nourishment by sucking the sap. One of the best known
is Tetranychus telarius, a little red mite, sometimes called the money-spider. The
web it spins is of very fine texture, and may usually be found on the backs of
leaves, where it appears to be merely used as a protective screen for both adults
and young. The silk is secreted from a conical nipple situated on the under side
of the extremity of the abdomen, and, as in the case of spiders, is manipulated
by the appendages. Also related to the Trombidiidce, but connecting them
with the next family, is the common mud-mite, Limnochares, which lives in
fresh-water ponds, creeping upon the mud or the leaves of aquatic plants. The
larva adheres to various water-insects. The
water - mites (Hydrachnidce) have been
described as Trombidiidce that have adopted
an exclusively aquatic life. They live in
fresh -water ponds and streams, where they
may be seen swimming freely by means of
vigorous strokes of their legs, which act like
oars. In the adult the body is generally more
or less spherical, and usually of a bright red
or green colour. The males of one species
(Atax globator) have a curious blunt tail-like
prolongation from the hinder end of the

abdomen. The eggs are laid in the spring, in the stems of water-plants which are
perforated for the purpose, and the six-footed larvae when hatched attach them-
selves to water - bugs (Nepa), or water - beetles (Dytiscus), by means of a large
sucker on the front of the head. The abdomen then starts growing, the feet
drop off, and the creature remains hanging like a sack to its host. One species
(Atax bonzi) lives in the shell of the fresh- water mussel, while a few (Pontarachna)
are marine. The next family (Halacaridce) contains marine forms differing from

the last in many important
features ; the mouth-parts
being more united. In
addition to the pair of
eyes on the carapace, there
is an unpaired eye upon
the epistome. These
marine mites do not
appear to swim like their
fresh - water allies, but
creep on the stems of sea-
weeds and zoophytes.
They may be obtained
either by dredging in deep
water or in rocky pools upon the coast. Passing on to the family Ga,masidce, we
find the stigmata placed far back in the body, frequently at the sides of the thorax,
above the legs of the third or fourth pair. The beak is imperfectly developed, the
palpi being foot-like and free, and the mandibles pincer-like. There are no eyes ;

1, bestls-mite, Gamasus coleoptratorum (much enlarged) ; 2, dor beetle,

INFESTED WITH GamasUS.

244

MITES AND TICKS.

and the legs are adapted for walking or running. The species figured (Gamasus
coleojrtratorum) may often be seen in numbers attached to the lower side of dor-
beetles. Others live parasitically upon bats and birds, one of the commonest
being Dermanyssus avium, which infests poultry, canaries, and other cage-birds,
whence they sometimes migrate to the persons who have charge of them. Ceylon,

Sumatra, and Mauritius are the habitat of Holo-
thyrus, in which the body is hard and horny, like
that of a beetle, and of a shining chestnut colour.

Of all the Acari the best known and most
troublesome are those belonging to the family Ixodidce,
which infest terrestrial vertebrates, and sometimes
attach themselves to men. They are furnished with
a longish cylindrical beak, armed with recurved
hooks, and formed by the two mandibles above and
the long slender labium below. The palpi are either
free, as in Argas, or closely applied to the beak,
forming in fact a sheath for it, and preventing the
escape of blood, which flows from the puncture made
by the beak. In the accompanying figure, showing
the mouth - parts of the common English dog- or
sheep-tick (Ixodes ricinus), the lower surface of the
e\C \ / ft capitulum, or head-like process, which bears the beak

» is shown at c ; d, e, f, g, represent the four segments

MOUTH-ORGANS OF SHEEP-TICK. Q| ^ palpi . £ fc ^ j^jgj procesg armed with th(J

c, Capitulum; d, e,f g Segments of h(X)ks £orming the lower side Qf the beak . and i
palp; i, Spiny -beak, formed by ° . , . .

fused mandibles. indicates the tips of the two mandibles, forming its

upper side, and projecting beyond the apex of the
labium. By means of this beak, which is thrust to its
base into the integument, the tick adheres firmly to its
host, and in detaching them care must be taken that the
head be not left behind buried in the skin. The species
/. ricinus is commonly found in all stages of growth (see
a, b, c, d, e, f of figure) adhering to cattle. The females
pump themselves full of blood, and swell up to the size of
a large pea; but the male — formerly regarded as a distinct
species under the name Reduvius — is of smaller size, and
resembles the empty female in shape. In distribution
these pests are almost cosmopolitan, but in tropical
countries they reach much greater dimensions than in
temperate climes, the females sometimes attaining the
size of a large gooseberry. In addition to mammals,
they attack birds, tortoises, snakes, and lizards ; and even
the thick hide of the hippopotamus and rhinoceros is of
no avail against attack. On account of their numbers,
the effects they produce upon cattle are sometimes of a
serious nature. These ticks are not, however, found

ENGLISH SHEEP-TICK.

Six -legged young; b, Eight-
legged young ; c, Male ; d,
Female not distended ; e,
Female distended with blood
from below ; /, Same from
above ; g, Specimen clinging
to the hairy integument of
a mammal. (All figures en-
larged twice.)

MITES AND TICKS.

245

DOG- Oil SHEEP-TICK

(enlarged).

exclusively upon their hosts; they also occur on the ground, and under stones,
where pairing and the hatching of the eggs take place. When in want of food,
both old and young climb the stalks of grass and shrubs, and clasping the tips
of the leaves with their fore-limbs, stand with the other legs stretched out behind,
ready to catch the hairy skin of cattle as they sweep through
the herbage. Also belonging to this family are the genus
Argas and its allies, the species of which nearly equal the
larger Ixodes in size, and although much less numerous in
species and individuals have almost as extended a distribution.
They may be at once distinguished from the latter by their
coarsely granular skin, flattish bodies, and the entire conceal-
ment of the capitulum beneath the projecting fore-margin of
the cephalothorax. The species here figured (Argas reflexus)
is habitually parasitic on pigeons, and occasionally occurs in
England in places where these birds abound. A closely allied

form from Persia — where it is known as the poisonous bug of Miana — is much dreaded
by the natives, its bite being said to produce convulsions, delirium, or even death.

The next family (Ori-

batidce) — the members of
which are sometimes called
beetle - mites, on account of
their hard and horny integu-
ment— contains a number of
species found for the most
part under the bark of trees
or in damp spots on the
ground, where they live by
sucking the juices of plants
and minute animals. The
palpi are free and tactile, the
mandibles pincer-like, and the
tracheae, when present, open in the socket of the last pair of legs. The last family
of true mites is that of the Sarcoptidce, which are either free or parasitic. They
have no special breathing-organs ; the palpi are basally fused to the rostrum, the
mandibles are pincer-like, and the tarsi are often furnished at their tips with a
sucker. The most familiar of those that are not parasitic
are the species known as cheese-mites (Tyroglyphus), which
feed upon decaying organic matter. The common cheese-
mite (T. siro), which has the body armed with rows of
long stiff bristles, is also found in flour and linseed meal.
Another allied species (T. entomophagus) frequently causes
much havoc among insect -collections, entirely destroying
the specimens if left unmolested, its presence in the cabinet
being usually betrayed by the fine dust that results from
its depredations. The most satisfactory method of destroy-

1 J J CHEESE-MITE (much

ing it seems to be soaking the cork of the box and the enlarged).

pigeon-tick, from above and below (much enlarged).

246

MITES AND TICKS.

itch-mite (enlarged 80 times).
(Lower view of female.)

specimens with benzine. A large number of mites living parasitically upon
mammals — such as the mouse-mite (Myocoptes) — and birds also belong to the
Sarcoptidce, ; but the only species that we have space to mention is the itch-mite
(Sarcoptes scabiei), which gives rise to the disease known as scabies. This

malady and the irritation accompanying it are caused by
the mite excavating tunnels under the skin. In these the
eggs are laid, and hatch ; and the young then start burrow-
ing on their own account. The burrows usually show as
whitish lines on the surface of the skin, and if the skin at
the end of one of these lines be pricked with a sharp
needle, the mite may be without difficulty extracted.

Worm-Like In the group Vermiformia the elongate

Group. abdomen is divided into a multitude of small
rings. There are no eyes and no tracheae. The suborder
contain only the two families Demodicidce and Phytoptidce.
In the former the adult is provided with four pairs of short
three -jointed legs ; the mandibles are styliform, and the
palpi formed of four segments, each armed with a claw. The family is represented
by Demodex folliculorum, a minute mite less than -fa of an inch in length, living
parasitically in the sebaceous sacs and hair-follicles of the human skin. The
same or an allied species has been found in the skin of a dog suffering from
mange, where they occurred in such quantities that thirty or forty might be seen
in a single drop of matter. The members
of the second family, commonly known as
gall-mites, have lost all trace of the third
and fourth pairs of legs ; the first and
second pairs only remaining and projecting
from the forepart of the body. These legs

are long and five-jointed, the mandibles are styliform, and the palpi tactile and
united at the base. The long body is furnished with symmetrically arranged
bristles. There are numbers of species, living exclusively upon the leaves of plants,
to which they do much damage by the excrescences or galls they form. Each
kind of tree seems to be infested by its own special gall-mite, the so-called nail-
galls of the lime being caused by a species named Phytoptu8 tilice. These galls
take the form of more or less cylindrical pointed columns, which stand erect on the
upper side of the leaves. As a matter of fact, they seem to arise as an inpushing
of the lower surface of the leaf to form a long pouch or pocket, in which the mites
live. Galls of much the same structure, although differing somewhat in shape,
occur in the sycamore, maple, elm, and various fruit-trees. Other species, like
the Pliytoptus of the currant and the yew, attack the young buds and prevent
them attaining maturity.

The mites and ticks complete the list of Arachnida ; there remain,
however, two small and obscure groups, which have been associated
with the ticks, but apparently for no better reason than that their affinities are
unknown. The first of these are the Tardigrada, or bear-animalcules, which com-
prise microscopical animals living in damp sandy and mossy spots. The body is long

Demodex folliculorum (enlarged 600 times).

Aberrant Types.

MITES AND TICKS.

'47

and oval in shape, and possesses four pairs of bud-like unjointed appendages, each
tipped with two claws. The last pair of legs projects from the extreme hinder end
of the body. The mouth is situated at the opposite extremity, but the only trace of
jaws that it presents is a pair of stylets. There appear to be no organs of respira-
tion or circulation ; and, unlike what obtains in all true Arachnida, the sexes are
united in each individual. The second group, Linguatulina or Pentastomida, is still
less like the Arachnida. It includes internal parasites, which in form and mode of
life present many points of resemblance to the intestinal worms. The body is long,
broad in front, narrowed behind, and divided into a vast number of rings. Near
the mouth there are two pairs of strong hooks, and although these are the only
traces of appendages that the adult presents, the embryo is furnished in addition
with two pairs of limbs, tipped with claws. It is mainly upon the evidence
furnished by these limbs that the Linguatulina are regarded as degraded mites.
One of the best known forms is Pentastomum tcenioides, which in the adult stage
lives in the nasal passages of dogs and wolves. From these hosts the embryos
escape to the outer world mixed up with the nasal mucus. Taken into the body
along with the food of the hare or rabbit, they emerge from the egg, penetrate the
walls of the intestine, and lodge themselves in the liver. Here they become
encysted, grow, and go through a series of changes of form, accompanied by
repeated ecdyses, until they pass into a state known as Pentastomum denti-
culatum. If the flesh of the rodent containing P. denticulatum be devoured by
a dog, the parasite passes into the skull of the dog, gradually takes on the form
of P. tcenioides, and acquires sexual organs. Another species has been found
living in the lungs of the Egyptian cobra, and a third in those of a species of boa.

E. I. POCOCK.

a spider's sriNNERETS (greatly magnified).

CHAPTER VII

The Jointed Animals, — concluded.

The Sea-Spiders, King-Crabs, and Crustaceans, —
Classes Pantopoda, Gigantostraca, and Crustacea.

The animals belonging to the first of the three classes named above present
such a marked general resemblance to the true spiders, that they have been
included in the same class. On the other hand, from their marine mode of life,
some writers have come to the conclusion that their affinities are rather with
the Crustaceans. As a matter of fact, it appears impossible to affiliate them with
either of these groups, and the general opinion is that they are entitled to form
a class by themselves. In all these creatures the adult is provided with four
pairs of well-developed legs, composed of a large and varying number of segments,

and each tipped with a single
claw. These limbs, which are
often exceedingly long and
slender, radiate from the sides of
the cephalothorax, which is pro-
duced into stalks for their support.
In front of these limbs, and
attached to the headpiece, are
sometimes three additional pairs of
appendages. Hence the full com-
plement of limbs is seven, and not
six pairs as in the true spiders.
The first pair of appendages, form-
ing the mandibles, are short and often pincer-like ; the second pair, or palpi, being
also short ; while the third pair, which are only developed in the females, are
shorter than the true legs, and, from their function, are termed the egg- bearing
legs. In some cases, however, these three pairs of appendages have entirely
disappeared, as in the shore-spider (Pycnogonum littorale). Projecting forwards
from the front end of the body is a long rigid beak, or proboscis, at the
tip of which the mouth is situated. This beak is not formed by the fusion
of limbs, like that of the ticks, but results from the great development of the
area immediately around the mouth. The cephalothorax is divided into four
distinct segments, of which the first, or head, supports the first four pairs of
appendages, and has on its summit a pair of eyes, while the rest bear the three
posterior pairs of limbs. Attached to the last of these segments, and projecting

FEMALE OF SLENDER SEA-.'iPIDER, WITH EGGS (much enlarged).

KING-CRABS. 249

backwards between the last pair of legs, is the abdomen, which is reduced to a
mere tubercle or rod-like process. The greater part of the body-cavity is occupied
by the stomach, which sends prolongations almost down to
the extremities of the four pairs of walking -legs. No
breathing-organs are known.

The sea- spiders are exclusively marine, and range
from shallow water to depths of sixteen hundred fathoms
or more. The conditions of life in the deep sea have by
no means a dwarfing effect upon them, since the species
living in the abysses of the ocean attain a size never
equalled by those frequenting the coast. Some of the shore-spider (enlarged).
former are of a very large size ; Colossendeis gigas, for

instance, covering a span of nearly two feet from toe to toe. None are able to swim,
but all crawl slowly amongst the branches of seaweed. The embryo emerges from
the egg as a larva, provided with a beak and three pairs of appendages, representing
the short anterior three pairs of the adult ; the four pairs of great locomotor limbs
being subsequently produced by outgrowths from a posterior elongation of the body.

The King-Crabs, — Class Gigantostraca.

In many respects the representatives of this class occupy a position intermediate

between the Scorpions and Spiders and the Crustaceans. From the fact that they

are marine and breathe by means of gills, they were formerly always classified with

the Crustaceans ; but a large amount of evidence has been brought forward to show

that whereas the earliest kinds are related to the primitive Crustaceans, the more

specialised kinds are strikingly like some of the Scorpions. The class contains

three orders, named Xiphosura, Merostomata, and Trilobita. The last two of these

are now entirely extinct, and the first named nearly so, since it is represented

at the present day by only a single genus, the king-crabs or horse-shoe crabs

(Limulus). In the existing: group, forming the order Xiphosura, the
Existin0, Forms o o j. > o j.

' body is armed behind with a long spike-like tail, movably articulated

to the middle of the hinder border of the abdomen. The abdomen consists of a
large unsegmented pentagonal plate, armed on each side with six movable spines,
and hollowed out below to receive six pairs of large flattened limbs, attached to
the anterior part of its lower surface. "With the exception of the first, each
limb supports on its hinder surface a bunch of fine branchial plates, arranged one
above another like the leaves of a book. In front of the abdomen comes the
cephalothorax, which is covered above with an enormous carapace, having its border
semicircular and its hinder angles acutely produced. The carapace is furnished
above with four eyes, two being small and simple ocelli, situated close together
some little distance behind the front border, while the others are large kidney-
shaped compound eyes, placed at a corresponding distance from the lateral
margin. The great size of the carapace is due to the prolongation of its edges
into a wide sloping shelf-like expansion, concealing the walking limbs. Of the six
pairs of the latter, the first are placed in front of the mouth, and are short, three-
jointed nippers ; while the rest are longer, generally six-jointed, and all but the

250

KING-CRABS.

last nipper-like, the last or sixth ending in a number of flattened plates. The
basal segments of the second, third, fourth, and fifth limbs are furnished with
large processes, projecting into the mouth and studded with numbers of slender
softish spines. The mouth is thus situated between the bases of these limbs, near
the middle of the lower surface of the cephalothorax. The males differ from the
females in having the second, or second and third pairs of limbs thickened and
otherwise modified. In the male of the round-tailed king-crab (Limulus rotundi-
cauda) the second and third pairs are considerably swollen, and the two fingers
of the nippers cross each other when closed ; whereas in the Moluccan king-crab
(L. moluccanus) the immovable fingers of these limbs are reduced to short processes.
In distribution, king-crabs are limited to the east coast of the United States,
to the shores of China and Japan, and of the Indo-Pacific Islands, ranging from the

CHINESE KING-CRAB.

Moluccas to Singapore and Java. In the last-named area two species, L. moluccanus
and L. rotundicauda, occur. The Chinese species is known as L. longispinus, on
account of the long and strong spines projecting from the carapace and abdomen ;
while the North American species is L. polyphemus. The habits of the last-named
species are tolerably well known. It spends the greater part of the year in water
from two to six fathoms deep, and, being unable to swim, creeps about the bottom
of the sea in search of food, or even lives buried in mud, into which it scoops its
way. This it effects by thrusting the front edge of the carapace forwards and
downwards into the mud, the tail behind being used as a prop, while the legs are
engaged in raking up the mud and pushing it out sideways. The tail is also of
service in helping the animal to regain its proper position if turned upside down.
Digging the tip of the organ into the soil, the crab raises its body, and after a few
efforts succeeds in struggling over. In fact, were it not for the possession of a
long tail, the king-crab would be as helpless on its back as a tortoise in the same
position.

King-crabs feed almost exclusively upon soft marine worms and bivalve
molluscs. The food is seized and tucked into the mouth by means of the legs,

KING-CRABS, ETC. 251

where the spines on the basal segments of these appendages crush and tear it to

pieces. In May, June, and July, large numbers of king-crabs approach the coast

in couples to spawn. Choosing spring-tides, they advance along the bottom until

the water is shallow enough to allow the carapace to project above the surface.

The female then scrapes a hollow in the mud, lays her eggs, and hurries back with

her mate into deep water. By the action of the waves the eggs are soon covered

with a layer of sand, and at ebb-tide are exposed to the warmth of the sun. When

first it emerges from the egg, the young king-crab is a minute nearly spherical

creature, with a fringe of stiff bristles running round the body, and differs from the

parent in having no tail. Subsequently it undergoes a succession of moults, during

which the form of the adult is gradually acquired, the tail appearing at the second

change. The casting of the skin is effected by the splitting of the integument of

the cephalothorax all round, immediately beneath the margin of the carapace.

Through the aperture thus made the creature struggles forth, leaving its old shell

behind. Before the growth of the tail the young king-crab is in a helpless state,

the slightest obstacle turning it upside down. In this emergency it starts a

vigorous flapping of its gill-plates, which cause it to rise in the water. Then

ceasing the agitation, it at once descends with a chance of alighting right side up.

The existing; king-crabs are the typical representatives of the
Extinct Types. .. . . & &. . z. f . r • 1 m •

family Limulidce, and fossil remains of Limulus occur in the Tertiary

rocks as wells as in the Cretaceous, Jurassic, and Triassic beds of the Secondary

epoch. In the Palaeozoic strata the class is represented by a number of forms, such

as Bellinurus from the Carboniferous, Protolimulus from the Devonian, and

Hemiaspis from the Silurian, which resemble Limulus in most of their characters,

but differ in having the abdomen composed of at least nine distinct segments. On

this account they are referred to a distinct family, Hemiaspididce. It is, however,

interesting to note that in the young king-crab the abdomen is also composed of

nine segments, so that just as in the life-history of each individual king-crab the

final and adult stage with a solid abdomen is preceded by a transitory stage in

which the abdomen is jointed, in the history of the class the existing and final

stage, represented by the adult king-crab of our own day, was preceded by a

transitory stage, which, in the segmentation of the abdomen, was on a level with

the young king-crab.

The seas in which these fossil forms lived were also inhabited
Merostomata.

by some nearly allied types, differing from the king-crabs, both in

habits and some important points of structure. The carapace, for instance, was

much smaller and did not conceal the legs, the last pair of which were generally

thickened and flattened, and transformed, as in Eurypterus, into powerful short

paddles. In one form, however, named Slimonia, the legs of the last two pairs

were enormously elongated, evidently to serve the purpose of oars. The abdomen

was used as a propeller, and it was long and divided into twelve flexible segments,

the last of which bore the tail-plate or telson. As in the king-crab, the bases of

most of the cephalothoracic limbs were armed with teeth and acted as jaws ;

but those of the anterior pair formed either short tactile organs or long and

powerful nippers, as in Pterygotus.

The Merostomata, as these animals are termed, appear to have lived both in

252

TRILOBITES.

Trilobites.

fresh and salt water, and their organisation seems to show that they were powerful
swimmers ; considering, too, the large size which some of the species attained,
examples of Pterygotus reaching a length of from 4 to 6 feet, there is little
doubt that these monstrous sea-scorpions were the masters of the ocean in
Palaeozoic times. A third order is represented by the extinct Trilo-
bites or Trilobata, which swarmed in the seas of the Palaeozoic epoch,
and are amongst the earliest of known fossils. The name Trilobite, or three-
lobed, is given to them because in the best known and typical members of the
group the body is divisible into three distinct parts — an anterior cephalic shield
corresponding to the head of the Crustacea and to the cephalothorax of Limulus,
and formed, as in Crustaceans, of five fused segments ; a median thoracic portion,

composed of a variable number of freely movable
segments ; and the pygidium, also composed of a
variable number of segments, but usually fused to
form a great caudal shield. The lateral portions
of the segments are produced sideways into great
pleural plates, which mostly conceal the limbs,
and the hinder angles of the cephalic shield are
frequently prolonged into sharp spiniform processes,
sometimes so long that they project backwards
beyond the hinder end of the body. On the upper
side of the cephalic shield there are a pair of large
kidney-shaped compound eyes, but no sign of the
simple eyes present in the Xiphosura and Meros-
tomata has been discovered. For many years no
trace of limbs could be detected, but it is now
known that a pair of limbs was attached to the
lower surface of each of the segments of the head
and body ; though instead of there being two pairs
situated in front of the mouth, as in Crustaceans,
there was only one, as in the Xiphosura, Merostomata,
and Arachnida. These, however, take the form of
long filiform antennae, and are placed on each side
of a large upper lip, or labrum, behind which comes
the mouth. The rest of the appendages of the head, as well as those of the
thorax, are alike, consisting of a large basal segment, from which spring two
branches, an inner, which was used for crawling, and an outer, many-jointed and
fringed with bristles, which was perhaps used for swimming. The basal segments
of these limbs in the head region were utilised as jaws, and in the pygidium the
inner branches, or endopodites, were flattened and more or less leaf -like as in the
lower Crustaceans, such as Apus. There is little doubt that Trilobites, instead
of swimming in the open sea and leading an active predatory life, spent their time
crawling or swimming slowly along the bottom, feeding upon worms, burrowing
in the mud, and, in case of danger, rolling up tightly into a ball like wood-lice.
Many specimens are found fossilised in this condition, with the lower surface of
the pygidium pressed against the head.

A trilobite (Triarthrus).
(From Beecher.)

CRUSTACEANS. 253

Crabs, Lobsters, Crayfish, etc., — Class Crustacea.

The Crustaceans comprise a large assemblage of Arthropods, presenting great
diversity of structure. Some of the parasitic species have become so simplified in
organisation that they appear to present no relationship with the higher members
of the class, such as crabs, lobsters, wood-lice, etc. Yet it is certain that all the
species, whether terrestrial or aquatic, free-living, sessile, or parasitic, belong to the
same stock, and may be derived from the same fundamental plan of structure.
Essentially the body consists of a large number of segments, to each of which
is attached a pair of two-branched appendages, the external branch being called
the exopodite and the internal the endopodite. Five segments at the front end of
the body unite to form a head ; the appendages of the first two of these segments
being situated in front of the mouth, and performing the office of feelers or
antennae, while those of the remaining three segments are transformed into jaws,
the first pair of jaws being the mandibles and the following two pairs the maxillae.
The rest of the appendages are variously modified, and to some are attached
respiratory organs in the form of gills. According to this definition, Crustaceans
may be distinguished from the Centipedes, Millipedes, Insects, etc., by the presence
of two pairs instead of one pair of antennae, and by possessing branchial and not
tubular (tracheal) respiratory organs. The Arachnida may be separated from
Crustaceans by having in front of the mouth only one pair of appendages, acting
as jaws and not as antennae, while respiration is effected by means of saccular
or tubular ingrowths of the integument. Nor can there be any confusion between
Crustaceans and the sea-spiders, since the latter have no antennae and all their
appendages are placed behind the mouth, which is situated at the extremity of a
tubular proboscis. But when we come to the Gigantostraca it is not so simple to
point out the differential characters of the Crustaceans. It is true that the king-
crabs are easily distinguishable, and appear to be more nearly related to the
Arachnida, yet the Trilobites, which seem to be ancestral forms of the king-crabs,
show marked affinities to the primitive Crustaceans.

In a few Crustaceans, especially those leading a terrestrial life, or inhabiting
fresh water, the young is very similar to the adult, and gradually attains maturity
without going through any marked change of form ; but
in the majority the young upon leaving the egg is unlike
the parent, and only acquires its definite form after
undergoing a series of moults. The earliest stage, which
has been called the Nauplius, is a minute oval body,
showing no trace of segmentation, and provided with a
single median eye, and three pairs of swimming
appendages, which become the two pairs of antennae and
the mandibles of the adult. This stage, however, is by
no means of invariable occurrence, but is chiefly char-
acteristic of the lowest members — the Entomostraca — (much enlarged).
and is rare in the higher Malacostraca. In some members

of the latter group, nevertheless, it does occur, as in one of the shrimps (Penceus).
In this the Nauplius passes into a stage called the Zocea, in which four pairs

254

CRUSTACEANS.

of appendages, representing the maxillae and the two following pairs of limbs
of the adult, have appeared, and the abdominal region has increased in length,
although, like the greater part of the thorax, is still limbless. A pair of compound
eyes is present on the sides of the head. After this so-called copepod stage, the
large eyes become stalked, the abdomen continues to increase in length, and takes
on the function of swimming, which was before performed by the antennae, and
the remainder of the thoracic and abdominal limbs appear. Since the thoracic
limbs are provided with a distinct exopodite, as well as the principal branch or
endopodite, as in the cleft-footed shrimps (Schizopoda), this larva is known as the

schizopod stage. Lastly, the median eye and the
exopodites of the motor-thoracic limbs disappear, and
the adult form of the Penceus is attained. It is, how-
ever, exceptional amongst the higher forms for the
young to be set free in the Nauplius stage. The young
of the lobster, for instance, hatches in the schizopod
condition ; while that of the common crab appears in
the Zosea form, although characterised by the presence
of a long dorsal spine, and a sharp beak on the carapace.
Moreover, the two pairs of antennae, the mandibles, and
maxillae, are of small size, while the following two pairs
of limbs are relatively large, and forked. By means
of these the minute transparent creature swims, and
after undergoing several moults passes into a stage termed the Megalopa, which
is much like the adult, but has enormously large eyes, and swims by flapping its
long jointed abdomen like a shrimp.

ZO.EA. stage of crab (enlarged).

The Typical Crustaceans, — Subclass Malacostraca.

Much difference of opinion still obtains as regards the classification of Crus-
taceans, which are here divided into two main subclasses. In the present group,
comprising the largest and most familiar forms, the number of segments in
the body is very generally nineteen (but never more), and each has a pair of
appendages. The first five segments compose the head, which, except in some
blind species, bears a pair of compound eyes, two pairs of antennae, and three pairs
of jaws, namely, a pair of mandibles in front, and two pairs of maxillae behind.
The eight segments behind the head, which constitute the thorax, may be united

JAWS OF CRAYFISH.

a, Mandible ; b, c, Maxillae ; d, e, f, 1st. 2nd, and 3rd Maxillipedes.

with the head, as in crabs, when the whole region is termed the cephalothorax, and
the shield that covers it the carapace. Sometimes too, as in the crayfish, the
anterior three pairs of thoracic appendages are transformed into jaws, and on this

CRABS. 255

account are called the maxillipedes, or foot-jaws; and in such cases only the

remaining five pairs, called the trunk limbs, are large, and used for locomotion or

seizing prey. In less highly organised forms, all the maxillipedes may be free and

foot-like, as in the mantis-shrimps, or only the anterior pair, as in sand-hoppers,

may act as jaws. The remaining six segments, forming the abdomen, are usually

provided with six pairs of small two-branched limbs, and to the last of these

segments there is articulated a single plate, or telson, while the limbs, or uropods,

are generally of large size, and form with the telson the tail-fin.

The Malacostraca are divisible into two series, the Podophthalmata, containing

those in which the eyes are perched on movable stalks, and the Edriophthalmata

containing those in which they are sessile, or if raised upon stalks not movable.

The former are further distinguished by having the forepart of the body generally

covered by a carapace ; in the latter some of the thoracic segments are movable

and there is generally no carapace.

The first order (Decapoda) of the stalk-eyed series is characterised
Decapods. . . . .

by having the posterior five pairs of thoracic limbs strongly

developed, and forming either walking or swimming legs, or prehensile pincers.

The three pairs of maxillipedes are generally transformed into jaws ; but in some

of the lowest forms, as shrimps, the third or last pair are long and limb-like, so

that in reality there are six pairs of large thoracic limbs. The gills, which are

attached to the sides of the cephalothorax and to the basal segments of its limbs,

are concealed in a gill-chamber, formed by the lateral portions of the carapace.

Each gill may be compared to a plume consisting of a central stem, to which is

attached a number of delicate processes in the form of flattened plates or of

filaments. The front aperture of the gill-chamber is closed by a movable plate

called the scaphognathite, and attached to the second maxilla. During life this

plate is in constant motion, baling out the impure water through the anterior

opening, and thus compelling a flow of fresh fluid into the chamber through the

openings at the hinder end of the carapace above the bases of the limbs.

Short-Tailed Group, — Suborder Brachyura.

Decapods are divisible into two suborders, the Brachyura, or short - tailed,
and Ma crura, or long-tailed group. The first-named suborder contains those
members of the order which may be called crabs. Here the abdomen, or so-
called tail, is small, and shorter than the cephalothorax, against the lower surface
of which it is usually tucked away. In the males it is generally narrow, and
bears only one or two pairs of appendages, but in the female it is broader
and is furnished with four pairs of limbs. In neither sex is its last segment
furnished with a pair of uropods forming the tail-fin. The lower surface of
the cephalothorax is generally broad and triangular, and the third pair of
maxillipedes are short and flattened, and form, when in contact, a plate completely
covering the rest of the mouth-organs. The group is divisible into five tribes, the
first of these being the Cyclometopa, or those with rounded foreheads. It includes
most of the commoner species, such as the edible crab (Cancer pagurus), and
shore-crab (Carcinus mcenas). The former belongs to the family Cancridce,

256

CRUSTACEANS.

YO0NG EDIBLE CRAB.

characterised by having the carapace much wider than long. As an article of
food the male is more esteemed than the female, being larger and having larger
claws. The two sexes, as in all crabs, may be distinguished by the size of the
tails, this organ in the male being narrower, more pointed, and having fewer and

smaller appendages than in the
female. The family Cancridcu
is represented in tropical seas
by a large number of species
and genera, some of which, such
as Actcea, have the carapace
covered with granules, and
ornamented with a network of
deep grooves.

The members of the family
Portunidce may be recognised
by a modification of the last
pair of legs. In the great
majority of crabs these legs are
like the rest, ending with a
long, slender - pointed foot, which bears evidence to its being an organ for
running, climbing, or crawling; but in the Portunidce these legs are much
flattened, the last segment in particular being dilated into an oval plate. The
creatures are thus equipped with a pair of oars, by means of which they swim
Several species of the typical genus Portunus are found in British waters, and
many of them are hand-
somely coloured, although
none are such expert
swimmers as the tropical
species, especially those
inhabiting the gulf-weed
of the Atlantic. The
peculiar motion of the
oar -like feet has given
rise to the name of
fiddler - crabs, so often
applied to the group.
The figured species
(Thalamita natator) is a
native of the tropical
seas. The common British
shore or green crab (Carcinus Tncenas), which is referred to this family, differs
from the rest in having the legs of the last pair adapted for walking, being armed
with a claw, and not flattened into a paddle. Connecting the present with the
following section, is the family Thelphusidce, which contains a number of genera
and species found in fresh- water streams, or on land, and sometimes ascending
mountains, in temperate and tropical regions. One of the best known species is

swimming-crab (nat. size).

o

3D

d

H
>
O
m
>

en

CRABS. 257

the South European Thelphusa fluviatilis, which swarms on the muddy banks
of the Lake of Albano, and is also abundant in the neighbourhood of Rome, where
it is captured for sale. Another well-known form is the Indian land -crab (T.
indica), to which the species here figured is nearly allied.

The second tribe (Catometopa) is characterised by the broad and squared
frontal region of the carapace being bent downwards. It is typically represented
by the family Gecarcinidce, including most of the true land-crabs. A large number
of these belong to the genus Gecarcinus, which has representatives in both the
Eastern and Western Hemispheres. Two inhabit the West Indian Islands, and of
one of these (G. ruricola) from Jamaica a full account has been given by
Mr. Browne.

These crabs are generally found at a distance of from two to three miles from

INDIAN LAND-CRAB (f Hat. size).

the sea, where they spend the day under stones, or in other sheltered situations.
Pairing takes place in the spring; and shortly afterwards the whole population
makes a move for the sea, in which the females lay their eggs. When seized with
this migratory instinct, nothing can turn them from their course. Issuing from
hollow trees, from under rocks, and out of innumerable holes, they muster in a host
so fast that they thickly cover an area more than a mile long, and upwards of
forty yards wide. The males lead the way, and the band proceeds in a straight
line to its destination, climbing over everything that comes in its road, be it
hedges, houses, churches, hills, or cliffs, and rather clamber up at the peril of their
lives than make a circuit. Having reached the sea, the females lay their eggs, and
the young hatch out as miniature copies of their parents. At the time of moulting,
which takes place late in the summer, the crabs retire to their burrows, close up
the apertures, and remain there out of harm's way until the old shell is cast and
the new integument hardened. It is while still in the soft state that these crabs,
which are eaten by the natives, are considered most palatable.

VOL. VI. 17

258

CRUSTACEANS.

The second family (Ocypodidce) is typically represented by the swift land-
crabs (Ocypoda), which appear to be less strictly terrestrial than the last, although
unable to endure a long sojourn in the sea. Indeed, from the adoption of a land
life their breathing-organs have become so modified that these crabs may be drowned

swift land-crab (nat. size).

by an immersion of twenty-four hours. They frequent sandy beaches, and when
chased run with such speed, as to make their capture a matter of difficulty.
They burrow deep perpendicular holes in the sand. In these they stay when
the tide is up, but at low water they wander over the beach in search of food,
which consists of sand-hoppers or any offal cast up by the waves.

These crabs are gregarious, in the sense that numbers frequent the same spot.
Each has a burrow to itself, and if one of them tries to enter by mistake the
burrow of another, the rightful occupant makes a loud scraping noise to warn the
intruder of its error ; whereupon the latter retreats in search of its own abode.
So strong is this instinct against trespassing, that a crab will always risk the
chance of a fresh run for safety, rather than persevere in seeking concealment in
the home of another.

Nearly allied to the foregoing are the calling-crabs (Gelasimus), represented by
a number of species from the warmer parts of the world. The carapace is broad
^^^ and squared in front, and the long slender eye-

stalks lie when at rest along its front border,
sunk in the orbits. But the most remarkable
characteristic is the enormous size of one of the
pincers in the male ; and it is from the habit of
brandishing this claw, as if beckoning, that the
name of calling-crab is derived. So abundant
are these crabs, that they may frequently be
seen by the thousands either running over the
sand or peering out of their holes. These holes,
which are thickly scattered over wide areas, lead into burrows frequently a foot
or more in depth. The crabs scrape up a heap of sand, and grasping the pellet
with three of the legs of one side, carry it to some distance before letting it

calling-crab (nat. size).

CRABS.

259

drop, then raising their eyes and peering round, dart back to the burrow,
scrape together another heap, and persevere in the same manoeuvre till the
burrow is of the required depth. It was long supposed that the pincers of
the male were used as weapons of attack and defence ; but, in addition to its
size, this limb is noticeable for its bright colours, and Mr. Alcock, who observed
a number of males of an Indian species (G. annulijies) waving their large
claws in the presence of a female, has suggested that their object in so doing
is to make a display of their gaudy ornamentation and thus influence her choice
of a mate.

The third family, Grapsidce, contains species which for the most part are
shallow -water forms. They are widely distributed, and attract the attention
of travellers both on account of their bright colours and their extraordinary

THORNBACK CRAB (§ liat. size).

activity. Possessing long and powerful legs, tipped with sharp strong claws,
they are able to dart amongst the rocks on the coast with amazing speed, while
by means of their flattened carapace and limbs they can slip away into the
narrowest clefts and chinks. Unlike the majority of the family, the little gulf-
weed crab (Planes minutus) occurs in temperate and tropical seas, amongst the
floating weed, and it is said that Columbus adduced its presence as an argument
in favour of the proximity of land when his sailors were on the verge of mutiny.
The crabs of the family Pinnotheridce have the carapace soft and membranous
and the orbits and eye-stalks small. An interesting fact connected with them is
their habit of living in association with other animals ; many species being found
hiding between the shells of bivalve molluscs, and they have also been discovered
lodged in the interior of sea-cucumbers. Entering this strange retreat in the zoaea
stage, they never quit it of their own choice.

In the next tribe, Oxyrhyncha, the carapace is generally narrowed in front
and wide behind, and furnished between the eyes with a distinct beak, which is

26o CRUSTACEANS.

sometimes double and of great length. On its dorsal surface the carapace is
usually roughened with spines or tubercles, and frequently furnished with hooked
hairs. These crabs frequent deep water, and, at least, on the English coast, are
regarded by fishermen as spiders. The characteristics of this group are shown
in the figures of two British species, the thornback crab (Maia squinado) and the
long-beaked spider-crab (Macropodia longirostris). Also belonging to this tribe is
Macrochira kcempferi, which is not only the largest crab, but the largest
crustacean known. It inhabits the seas of Japan, and is said to be able to span
eleven feet with its outstretched pincers.

A peculiarity of many of this group is their extreme untidiness, owing to the
quantities of seaweeds, zoophytes, and other marine objects affixed to the carapace
and limbs ; and it has been ascertained that the presence of these extraneous
bodies is not the result of chance, but that they are placed there, presumably
for the purpose of concealment, by the crabs themselves. This feat they are
enabled to perform owing to the flexibility of their pincers, and to the hooked
hairs and spines with which the carapace is studded. Some examples of Hyas,
deprived of their covering of foreign bodies, were placed under observation in an
aquarium of which the bottom was covered with a layer of sponge. Contrary
to their habitual sluggishness of manner, the crabs appeared much perturbed,
running first to one side then to the other in the aquarium. Soon, however, by
means of their pincers they tore off small fragments of the sponges, and, after first
putting them to their mouths, placed them finally upon the dorsal surface of the
carapace or limbs, sticking them there with a rubbing movement. Sometimes
after several vain efforts the crab brought the fragment afresh to its maxillipedes
and then repeats its efforts to make it adhere. The animal persevered in these
manoeuvres until the piece of sponge remained fixed in the spot where it wished
to place it. By continuing to act in this fashion the crab succeeded in com-
pletely changing its appearance, and in rendering itself indistinguishable amongst
the objects that surrounded it. The crab proceeded in exactly the same
fashion when the bottom of the aquarium was strewn with seaweeds or any
kind of zoophytes. Moreover, it was observed that some specimens, clothed with
seaweed, which were left in an aquarium of which the bottom was covered
with sponges did not hesitate to take off their old clothing and put on a new
one of sponges.

The present tribe also contains the family Parthenopidw, the species of which,
although not armed with spines and hooked hairs for holding foreign objects,
are yet protected in the midst of their surroundings, by having the carapace
covered with pits and variously shaped depressions, giving it a roughened corroded
appearance, and consequently imparting a resemblance to pieces of rock or
fragments of dead coral.

The sharp-nosed crabs, forming the tribe Oxystomata, are so called because the
carapace is produced in front into a short beak-like prominence, while the external
maxillipedes which cover the mouth are narrowed and pointed at the apex. The
families belonging to this group present great diversity of structure and habits,
the Matutidce being active swimmers and resembling the Portunidce in having
their posterior legs transformed into flattened paddles, while the Calappidce, which

CRABS.

261

live a sluggish life on the floor of the sea, have the sides of the carapace produced
into shelf-like plates covering the legs, and the upper edges of the pincers supplied
with large crests. The latter shut in the cephalothorax in front, so that when at

LONG-BEAKED SPIDER-CRAB (iiat. size).

rest the whole animal is enclosed in a casing of shell, and resembles a smooth
pebble on the sea bottom. Some of the species of the family Leucosiidce are
remarkable for the porcelain - like appearance and texture of the carapace,
while in others, as in Ebalia, this plate is granular and corroded. Three or four
species of the latter genus occur in British waters, but the majority of the
Oxystomata are inhabitants of the tropics. In the genus Dorippe, belonging to
the family Dorippidce, the last two pairs of legs are short and raised on the upper
surface of the body behind the carapace. In
this position and structure they are adapted
for carrying foreign bodies to serve as a
protection.

The aberrant forms constituting the
tribe Anomala differ from the other members
of the suborder in having sometimes as
many as fourteen pairs of gills, and also in
that the apertures of the oviducts are situated
upon the basis of the third pair of legs and dromia crab (nat. size).

262 CRUST A CEANS.

not upon the breast-plate of the cephalothorax. Moreover, as in the Dorippidce of
the preceding tribe, the last or last two pairs of legs are shorter that the rest, and
dorsally placed, as shown in the illustration of the common Dromia vulgaris.
The crab uses these limbs to hold foreign bodies like sponges and shells beneath
which it thus lies concealed.

Long-Tailed Group, — Suborder Macrura.

This suborder, comprising the lobsters, hermit-crabs, prawns, and shrimps, is
distinguished by having the abdomen or tail usually of large size, and constituting
a powerful flapper for swimming, in which function it is assisted by the
enlargement of the appendages of its last segment to form with the telson a
powerful tail-fin. The external maxillipedes are slender and leg-like, and the
antennae usually longer than the body. The first tribe, Anomura, contains forms
which typically have a symmetrical tail. With these were originally classified the
anomalous crabs, and there is no doubt that some of the species bear a striking
resemblance to the latter. This is shown in the illustration of the broad-clawed

porcelain -crab (Porcellana platycheles), which frequents
rocks and seaweed at low water. It may be distinguished
from the true crabs by its long antennae, the presence
of a tail-fin, and the slender unflattened external maxil-
lipedes. The most familiar members are the hermit-
crabs, which abound in all seas, and are represented by
several British species. In the typical forms, the integu-
ment of the abdomen is soft; and, aware of its defenceless-

BKOAD-CLAWED PORCELAIN . .,-

crab (nat. size). ness, the hermit-crab invariably thrusts itself tor protection

into some empty shell, which it subsequently never
willingly quits, save for the purpose of changing its abode for a larger one, when
compelled by the exigencies of growth. It is not an uncommon thing to find shells
containing a hermit-crab surmounted by a large anemone. The advantage to the
crab of this association is considerable, for anemones are so distasteful that no fish
will bite at them twice, and consequently a fish that would, under ordinary circum-
stances, greedily swallow a hermit-crab, shell and all, will not so much as sniff at it if
protected by an anemone. One of the commonest deep-water British hermit-crabs,
Eupagurus prideauxi, is invariably found associated with an anemone, but the
latter adheres to the lower surface of the shell in such a manner that its mouth
and tentacles are situated immediately below the forepart of the crab's body. It
is thus able to share in the meals that the crab procures for itself, and the com-
panionship is consequently mutually beneficial to the two. An advantage conferred
upon the crab by the presence of the anemone results from the fact that the latter
gradually absorbs the shell in which the former is lodged, so that there is no
occasion for it to change its abode with growth, the soft tissues of the polyp
offering no resistance to the crab's increase in size. Certain hermit-crabs have
forsaken the sea as a permanent abode, and spend the greater part of their lives on
land. For instance, the genus Cenobita, which occurs both in the West Indies and
India, may be met with in forests far from the coast. The best known of these

HERMIT CRABS.

LOBSTERS, CRAYFISH, ETC

265

terrestrial forms is the great cocoa-nut crab (Birgus latro), found in the islands of
the Indo-Pacific seas, and remarkable not only for its great size and habits, but also
for having the abdomen symmetrical and covered above with a series of horny plates.
These animals inhabit deep burrows, which they hollow out beneath the roots of

trees, and carpet with fibres stripped __., — ; ^_ _mJ= ^ ^^^.^

from cocoa-nuts. Periodically, how-
ever, they are compelled to visit the
sea to moisten their gills ; and here
they lay their eggs, the young being
hatched and living for some time on
the coast. They live principally
upon cocoa-nuts, which fall from the
palms, but they do not climb the trees
after the fruit. To get at the con-
tents of the nut, the crab first tears
away the fibre overlying the three
" eyes," and then hammers away
with its claws at the latter until a
hole is made, when it extracts the
kernel by means of its smaller
pincers. Some observers state that
after drilling through the perforated
eye, the crab grasps the nut in its
claws and breaks it against a stone.

In the next tribe, or Thalas-
sinidea, the carapace is much com-
pressed and has a small rostrum, but
the abdomen is well developed and
often wider in the middle than in
front. As in the short-tailed group,
the fourth pair of thoracic limbs are
enlarged and generally completely
chelate, while the four succeeding
pairs, of which the last is smaller
than the rest, usually terminate in
simple claws. All the members of
this group are exclusively marine,
living at the bottom of the sea
buried a foot or more in the mud.
The accompanying figure represents
a species (Thaumastocheles zeleuca)
obtained at a depth of four hundred fathoms in the West Indies. It is character-
ised by the extraordinary development of the pincers of the right claw, which are
not only very long and slender but beset with spine-like teeth. The creature is
totally blind, having lost both eyes and eye-stalks.

In the tribe of the Scyllaridea none of the limbs of the thorax are truly chelate,

one-clawed lobster, Thaumastocheles zeleuca (nat. size).

266

CRUSTACEANS,

and the antenna? are not furnished with an external scale-like basal piece. The
best known members of this group are the Palinuridai, or rock-lobsters, one member
of which, the crawfish (Palinurus vulgaris), may be seen for sale in England.

It is larger than the lobster,
and has enormously long stout
antennas, and a spiny carapace
but no claws. This species is
figured on the left side of
the coloured Plate. The second
family, Scyllaridce, contains a
considerable number of genera
(Scyllarus,Ibacus, etc.), mostly
from tropical seas, remarkable
for having the carapace broad
and flattened, with the eyes
enclosed in complete orbits on
its upper surface, and the
antennae short and scale-like.
In this tribe the larvae are
larva of crayfish, the so-called "glass-crab (nat. size). unlike those ot crabs or

lobsters. On account of their
transparency and delicacy they are called glass-crabs. The body is formed of three
distinct parts, a large round-sided head, a smaller but also round-sided thorax, and
a minute jointed abdomen which projects like a short tail from the hinder end of
the thorax. The abdomen bears no limbs.

The lobsters and crayfish (Astacidea), have at least three pairs of the
large thoracic limbs pincer-like, the first being much larger than the others. The

slender- clawed cratfish, Willemcesia leptodactyla (nat. size).

LOBSTERS, CRAYFISH, ETC

267

antennae are furnished with a distinct basal scale-like plate. The first family
{Eryontidai) contains several genera found in deep water in various parts of the
world, the slender-clawed Willemcesia leptodactyla occurring in both the Pacific
and Atlantic Oceans, at depths varying from thirteen hundred to over two thousand
fathoms. As in many deep water species the eye-stalks are rudimentary. The
five posterior pairs of thoracic limbs are chelate in both sexes, and the first pair of
antennae have their inner branches long, while the carapace is flattish with a small
rostrum.

The remaining three families, namely, the Nephropsidcz, or lobsters, the
Potamobiidw, and Parastacidce, or true crayfish, are nearly allied. Among the

common crayfish (slightly reduced).

former, the Norway lobster {Nephnyps) is smaller than the common lobster, and
has the pincers long, slender, and covered with scale-like tubercles. The common
lobster (Astacus gammarus), from a commercial point of view, is one of the most
important Crustaceans. The crayfish (Potamobiidce), which live exclusively in fresh
water, are very like small lobsters ; the species known as Potamobia jluviatilis
being found in many streams in England. Throughout the day crayfish usually
lurk under stones or the edge of banks, and creep out in the evening in search of
food, which consists of worms, water-insects, small frogs or fish, and plants and
roots of many kinds. During the winter they seek the shelter of crevices or

268

CRUSTACEANS.

excavate deep burrows in the banks. In these they lie, with their antennae
stretched forward, and their claws ready to seize any passing object that may
serve for prey. Pairing takes place in the autumn, and the female retires to her
winter - quarters to deposit her eggs, which vary in number from one to two
hundred. After being laid, the eggs are attached to the abdominal limbs of the
mother. During the winter they develop slowly and are not ready to hatch until
late in the spring or the early summer. The young, which at first much resemble
the parent and go through no metamorphosis, adhere tightly to their mother's
limbs, and do not leave her until able to shift for themselves. Growth, however,
although fast at first is a slow process, the crayfish not reaching maturity until
about five years after birth. They probably live under favourable conditions for

common peawn (nat. size).

about fifteen or twenty years. Although not considered a delicacy in England, on
the Continent and especially in France, they are much appreciated. It is said that
in Paris alone from five to six million crayfish are consumed annually, and to
meet the demand large numbers are imported from Germany and elsewhere, and
artificial cultivation has been carried on with success. The crayfish belonging to
this family are found in the Northern Hemisphere ; but in the Southern Hemi-
sphere several forms occur which are referred to another family, Parastacidce,
differing in the arrangement of the gills. Some of these forms are of large size, the
Tasmanian Astacopsis franklini measuring a foot or more in length.

The next tribe, Caridea, embraces the shrimps and prawns, in which the last
three pairs of thoracic limbs are never chelate, although the two pairs in front of
them are frequently so. The tribe is divided into three sections. The first of
these, or Crangoninea, contains the family Crangonidce, or shrimps, characterised
by having the first pair of trunk-limbs subchelate, that is, with the terminal segment

LOBSTERS, CRAYFISH, ETC 269

capable of being folded back upon the penultimate. The common shrimp {Crangon
vulgaris) occurs in shallow water on sandy coasts of temperate countries of the
Northern Hemisphere. Its colour is a speckled grey, corresponding closely with
that of the sandy sea-bottom upon which it lives, and in which it buries itself when
threatened with danger. To escape the vigilance of fish, shrimps resolutely keep
themselves hidden during the day, but come forth at night to hunt for food. The
presence of this they perceive by means of scent, since a blind shrimp will find food
as quickly as an uninjured one. A second British species is Allman's shrimp
(Crangon allmani), abundant in deep water in the Irish Sea and on the west
coast of Scotland. It may be at once distinguished by the presence of two fine
keels on the upper side of the sixth segment of the abdomen. Both have a short
rostrum and no spines on the carapace ; but some of the other members of the
family have crests of spines on the carapace, and sometimes a largish rostrum as in
the Arctic Sclerocrangon boreas. In Rhynchocinetes typus, from the South Pacific,

WEST INDIAN prawn, Atya (nat. size).

this rostrum is not only large but movably jointed to the carapace. The section
Monocarpinea differs from the last in having the first and second trunk-limbs
completely chelate, and the second pair larger than the first. To this section
■belong a number of fresh- and salt-water forms, and amongst them the Palamionidai
or prawns. The general form of the body is shown in the figure of the common
prawn (Leander serratus). In its native haunts the prawn is nearly invisible,
being almost colourless, translucent, and marked merely with streaks of various
tints. In the rivers of tropical countries occur prawns (Palamion) rivalling lobsters
in size, and remarkable for the length of their pincers, which may exceed that of
the body. Among the largest are P. jamaicensis from the West Indies and Central
America, and the Indian P. lar, so much esteemed when cooked as a curry. Also
belonging to the same section is the family Atyidai, containing a few genera such
as Atya and Caridina, found in both Eastern and Western Hemispheres in fresh-
water streams and lakes. In Atya the trunk-limbs are curiously constructed, the
first two pairs being short and subequal with the two fingers of the pincers tipped
with a long tuft of hairs. The remaining three pairs, of which the first is much the

270

CRUSTACEANS.

stoutest, end in simple claws, and are studded with scale-like or spiny tubercles.

It feeds on the organic matter contained in the mud which it gathers up in its

nippers, compresses into pellets, and

transfers to its mouth. The two

small Crustaceans figured in the

illustration belong to the family

Pontoniidce. Both are semiparasitic

in habits, Pontonia living between

the valves of mussel shells, and

Typton being a lodger in sponges.

The Polycarpinea contains those

species in which the wrist of the

second pair of trunk-legs is divided

into several secondary segments. In
1, mussel-prawn (Pontonia tyrrhena) ; 2, sponge-prawn 1 it i

{Typton spongicoia). (Nat. size.) other respects they are nearly allied

to the last group. A common British
representative is the red shrimp (Pan-
clalus montagui), which gives its name
to the family Pandalidce, and is abund-
ant upon many parts of the British
coasts. This tribe is abundantly repre-
sented in tropical seas by the hooded
shrimps (Alpheidce), remarkable for the
concealment of the eyes beneath the
edge of the carapace, and for the
enormous size, bright colours, and
peculiar shape of the right or left
pincers. With this instrument the
hooded shrimps, which frequent holes
and crevices in the coral-reefs, are able
to produce a clicking sound when angry
or alarmed by the approach of danger.
The last tribe of the suborder, known
as Penseidea, appear similar to the
Monocarpinea, but may be distinguished
by the circumstance that the first three
pairs of trunk - limbs are chelate, so
that only the posterior two terminate in
simple claws. Some of the species of the
genus Penceus, belonging to the family
Penceidce, attain a large size in tropical
seas, and form an important article of
commerce. Nearly allied is the little
Spongicoia venusta, which makes its
home in glass-sponges. In this neigh-
bourhood may be placed the anomalous

hooded shrimp, Alphens (nat. size).

LOBSTERS, CRAYFISH, ETC

271

family, Sergestidce, in which the gills are impoverished or lost, while the first

pair of trunk-legs and sometimes the second are simple, the chelae of the third are

minute, and the fourth and fifth pairs

are feeble, rudimentary, or absent. To

this family belongs the genus Leucifer,

remarkable for having the eyes and

antennae supported at the end of a long

neck which extends in advance of the

mouth. The gills are absent, respiration

being effected by means of the general

integument, which is so thin that the

internal organs can be seen. In the

figure the dark line (n) is the ventral

nerve - chord which throws out finer

branches from ganglionic swellings in

each of the segments ; (h) is the heart,

while immediately below the latter is

the stomach, passing forwards into the

gullet and backwards into the intestine.

Cleft-Footed Group,-
Schizopoda.

-Order

This name is applied to a group
nearly allied to the long-tailed Decapods ;
the chief difference between them being
in the fact that in the present order the
eight thoracic limbs are similar in struc-
ture, each being pecliform and provided
with a distinct exopodite on the second
segment. The gills, which are attached
either to the thoracic or abdominal
appendages, generally project into the
water, and are but rarely concealed in a
chamber. The eggs are carried by the
female beneath the trunk, and are fre-
quently protected by the development of
a pouch. The order contains several
families embracing a large number of
mostly marine forms, some of which occur
at great depths. Of the British species,
the finest is Nyctiphanes norvegica, which
forms an important part of the food of
herrings. It has luminous organs on the
thorax and abdomen, and when swimming in a glass vessel, in a darkened room,
appears like a flash of light. The young, as in all the members of the family

long-necked shrimp, Leucifer (much enlarged).

2"]:

CRUSTACEANS.

Euphausiidce, are hatched in the Nauplius stage. Most Schizopods are small, but
species belonging to the genera Lophogaster and Gnathophausia measuring as
much as 6 inches in length have been obtained. To the family Mysidce belongs
the genus My sis, or opossum-shrimps, among which is M. veheta from certain lakes
in Northern Europe. Into these lakes the species is presumed to have entered
while they were connected with the sea ; a supposition borne out by the fact that
it is nearly related to M. oculata, now living in the Arctic Ocean.

The Mantis-Shrimps, — Order Stomatopoda.

The mantis-shrimps (Squillidce), which owe their name to the resemblance
that their seizing limbs bear to those of the insect mantis, are abundant in tropical

seas, where they sometimes reach a large size.
Although bearing a general likeness to the long-
tailed Decapods, they may be recognised by
certain prominent characters. A glance at the
accompanying figure will show that the carapace
is so short as to leave the hinder segments of
the thorax uncovered, and, since the gills are
attached to the abdominal limbs, it forms no
branchial chamber. Only three pairs of limbs
are modified into jaws, these being the mandibles
and two pairs of maxillse. The remaining eight
pairs of thoracic limbs are foot-like, the large
prehensorial pair corresponding to the second
maxillipedes of a Decapod. Two kinds of
mantis-shrimp are occasionally met with in the
English Channel, namely, Squilla desmaresti
and 8. mantis. The former is not uncommon
along the shallower parts of the shores of
Jersey, but as it lives in deep burrows among
the roots of sea-grass, in a zone never uncovered
by the tide, its appearance is infrequent. The
allied North American Lysiosquilla excavatrix
is found in the sand below low -water -mark,
where it is protected from the full force of the
ocean swell, and inhabits deep cylindrical
burrows which are nearly vertical and go down
mantis-shrimp (reduced). tor several teet.

Sessile-Eyed Series, — Edriopthalmata.

We now come to the second great series of the Malacostraca, in which the
compound eyes are generally sessile, and never mounted on movable stalks. As a
rule, the last seven segments of the thorax are not covered by the carapace, and
the last four are always free. The first order, Cumacea, is in many respects inter-

STOMA TO POD A. 2 7 3

mediate between the typical members of the last and present series, the thorax being
larger and broader than the abdomen, while the carapace covers all but the last
five segments. The front angles of the carapace are produced to meet in a kind
of beak in front of the head, and the eyes are generally united in a single cluster
of ocelli. None of the thoracic limbs are prehensile or chelate. The first five
segments of the abdomen have no appendages in the female, although such limbs
are present in the male. In the sixth segment appendages are present in both
sexes, and form a fork-like termination to the body. Two of the best known
genera of the group are Cuma and Diastylis. The order, however, is relatively
a small one, containing only a little over a hundred species. It has, nevertheless,
a wide distribution, forms being met with in shallow and deep water in all seas,
although the Arctic Ocean produces individuals of the largest size and in the
greatest abundance.

Order Isopoda.

Unlike the last, this second order of the series exhibits great diversity of
structure. As a rule, the posterior seven segments of the thorax are free, and
at least the first three, and generally the first five segments of the abdomen are
short and sometimes fused together, while the sixth is the largest, and bears the
telson and a pair of appendages. The other abdominal appendages usually
overlap, and are modified to act as gills. The seven thoracic limbs are generally
large, and perform the function of walking or swimming organs, while the
posterior five pairs at least have no exopodites. There are four pairs of jaws,
namely, the mandibles, two pairs of maxillae, and one pair of maxillipedes.
Although there are many exceptions, it may be said that, as a rule, the body is
broad, short, and flattened. Corresponding to the structural variations, the
Isopods exhibit great diversity of habits and habitat. Most are marine, occurring
in shallow waters or at great depths. Some live in fresh water, others on land,
while others have taken to a parasitic life, and have thus to a great extent lost the
characters of the order.

Of the five tribes, the Valvifera have the posterior pair of abdominal
appendages, or uropods, transformed into valves or flaps, covering part of the
lower surface, and constituting a chamber for the gills. The tribe contains two
families, the Arcturidce and Idoteidce. The former are distinguished by their
slender cylindrical shape, long lower antennae, and the length of the fourth
thoracic segment, which separates the posterior three pairs of thoracic legs from
the anterior pairs by a wide space. The anterior thoracic feet are slender and
hairy on the inner side, while the posterior feet are strong and prehensile, and
enable the animal to fix itself to the branches of corallines. In the Idoteidce the
body is longish and narrow, the thoracic segments being all of about the same
size and shape, and their appendages short, stout, and used for walking. The
anterior segments of the abdomen are short, and the posterior fused into a
caudal shield. The species of the genus Idotea live in shallow water, and
frequent places where there is an abundance of decomposing seaweed. They are
essentially carnivorous, feeding on dead fish, worms, and molluscs.

vol. vi. — 18

74

CRUSTACEANS.

The tribe Flabellifera contains a part of marine species, in which the abdomen
terminates in a tail-fin, formed as in the macrurous decapods from the telson and
the limbs of the last segment. There are too many families to mention, but some
of the characteristic forms are shown in the accompanying illustrations. In the
genus Serolis, which alone represents the family Serolidce, the body is depressed
and broad, the segments of the thorax being furnished with long pointed side-
plates, which impart to the animal a superficial resemblance to a trilobite. The
legs and two pairs of antennae are long. It is stated that the Serolidce " live by
preference on sandy ground, into which they burrow with their flat bodies up

Serolis bromleyana (nat. size).

to the caudal plate. Their nourishment appears chiefly to consist of the organic
materials distributed in the fine sand, diatomacea and organic detritus. Their
locomotion is carried on less by swimming than by backward movements on the
sandy ground, wherein the widely separated feet are used as a point of support."
The species figured (S. bromleyana) is the largest, and has been taken at a depth
of nineteen hundred and seventy-five fathoms. In the Sphceromidce the convex
body is capable of being rolled into a ball. Several species of Sphceroma occur
on the coasts of Britain, and may be found, sometimes in numbers, sometimes
isolated, beneath stones or amongst seaweed at low water. The next family
(Gnathiidce) contains the genus Gnathia, in which the males and females are so

ISOPODA.

75

Sphceroma (enlarged).

dissimilar that they were referred to two families. In the adult male the
mandibles are powerful and prominent, and the head is large, squared, and at
least as wide as the thorax. In the adult female, on the con-
trary, the head is small and triangular, without visible man-
dibles, and the thorax is much dilated. Many species are known
from the European coasts, and one has been obtained at a depth
of nine hundred fathoms. Belonging to this tribe, but repre-
senting a family by itself, is Limnoria lignorum, known to
fishermen as the gribble, which is a persistent destroyer of
submerged wood. The creatures are about one-sixth of an inch
long, and of an ashy grey colour ; and the destruction they
bring about is due to their habit of boring into timber below
water-mark. They are vegetarians, and feed on the wood which
they excavate. The members of the group known as fish-lice

are mostly of large size, the body being longish and
oval, and the antennae fixed on the front of the head,
which bears in addition two large eyes. The anterior
three pairs of thoracic limbs are stout and prehensile,
terminating in strong curved claws, while the posterior
four pairs are longer and thinner, and adapted for
crawling. By means of their powerful fore-feet the
CymothoidcB attach themselves to both marine and
fresh-water fish, and have a liking for the inside of
the mouth of their hosts.

Another tribe is the Epicaridea, the members of
which live parasitically upon other crustaceans. The
form of the body in the female is, as a rule, distorted
and unsymmetrical ; but the smaller males are sym-
metrical, and are usually found adhering to the females.
No group of Crustaceans seems exempt from the attacks
of these parasites, but it is said that each species has its peculiar kind.

The best known example of the tribe Asellota is
Asellus aquaticus, distributed in fresh- water ponds and
ditches almost all over Europe The creature is of a
greyish colour, mottled with paler markings ; and the
male, which is longer than the female, measures about
half an inch long. The body is long, narrow in front,
with a small head, and the antennae of the second pair
are about as long as the body and head taken together.
The seven segments of the thorax are free and of large
size, but those of the abdomen have coalesced into a
plate, from the end of which the long slender forked
uropods project. The seven thoracic limbs are long,
slender, and increase in length from the first to the
seventh.

The tribe Oniscoidea contains the wood-lice, in female gnathia (enlarged).

male gnathia (enlarged).

276

CRUSTACEANS.

which the abdominal appendages are modified for breathing air. Like all
crustaceans that have adopted a terrestrial life, they seem able to live only in air
saturated with moisture. The body is usually broadly oval, convex above, and
flat or hollow beneath, widest in the middle, and gradually narrowing towards
the head and tail. The head is small, but the thorax large and seven-jointed, the
abdomen being short. Representatives of this tribe are found in all quarters
of the globe. A familiar British species is the sea-slater (Ligia oceanica), a
large species living amongst the stones and rocks upon the coast above high water.
The creature is nocturnal, and unless disturbed is not often seen during the day,
but issues from the cracks and clefts of rocks in numbers at night. More obtrusive

are the common wood-
lice Porcellio scaber and
Oniscus asellws, the for-
mer distinguishable from
the latter by its duller
colour and the granules
upon its segment ; Oniscus
being smooth and more or
less variegated. Both
these are rather flat, and
incapable of rolling up
into a ball ; but the pill
wood - louse (Armadil-
lidium vulgare) has the
dorsal surface more con-
vex, and when handled rolls up into a ball. On account of their resemblance
to pills, these creatures were used for various maladies. In addition to its rounder
shape, the pill wood-louse may be recognised by the fact that the appendages
of the last abdominal segment (the uropods) do not project like a couple of
small tails from the hinder end of the body. Members of this group, differing
but little from the species described, are widely distributed in all temperate and
tropical parts of the world.

The tribe Phreatoicidea can only be briefly noticed. It contains the genus
Phreatoicus, of which two species — both inhabiting fresh water — are known, one
from New Zealand, and the other from Australia. The body is long and laterally
compressed, the seven thoracic appendages are well developed, and the first is sub-
chelate as in many Amphipocla, and the abdomen consists of six distinct segments,
with the gills attached to its appendages. The last tribe, Chelifera, containing the
genus Tanais and others, approaches the next order, and is distinguished by
having the first pair of appendages following the jaws — that is the second maxilli-
pedes — pincer-like. It further differs in that the abdominal limbs are used
rather for swimming than for respiration; the breathing -chamber is situated
in the posterior portion of the thorax, and a constant circulation of water is
kept up within it by the movement of a process projecting backwards from the
maxillipedes.

common and pill wood-lice (nat. size).

AMPHIPODA.

277

Order Amphipoda.

The Amphipods are allied to the Isopods, but the majority are recognisable
by having the body narrow and flattened from side to side, instead of broad and
flattened below. Moreover, the gills are attached to the thoracic feet, and the
latter, instead of being
broad, leaf - like, and
overlapping, are foot-
like, elongate, and used
for leaping or swim-
ming.

In the suborder
Gammaridea the eyes
are mostly of small
size, and seldom pro-
minent. The head
does not coalesce with
the first segment of
the thorax, and the

maxillipedes have a distinct palp ; the abdomen being well developed, and
bearing appendages. The form of the body is shown in the illustration of the

fresh- water shrimp (Gammarus pulex), and the sand-
hopper (Talitrus locusta). The latter lives near the
edge of the sea, beneath seaweed, or other substances,
which prevent the evaporation of the moisture from
the sand. Sand-hoppers usually progress on land by
leaps; and although some nearly allied forms are
found far from the sea, the majority of the Gam-
maridea are marine, swimming by means of the con-
stant play of their abdominal appendages, and, when
thrown on the land, wriggling helplessly along on their

fresh-water shrimp (enlarged).

sand-hopper (enlarged).

sides. The fresh- water shrimp
is common in the streams and
ditches of Europe. During
the cold months of the year
they bury themselves in the
mud, but emerge from their
winter-quarters on the first
warm days of spring.
Amongst deep-water forms,
perhaps the most noteworthy
are Acanthechinus tricar i-
n atus, and Andania gigantea.
The former has developed a
spiny process at almost every
possible point, each of the

spiny shrimp, Acanthechinus tricarinatus (nat. size

278

CRUSTACEANS.

principal segments bearing three large and pointed spines, which have their edges
armed like the blades of a saw. Very different is Andania, which is one of the
largest of amphipods, reaching a length of 2 inches. Many members of the group

construct tubular dwelling-places, in
which they take shelter, and lay their
eggs. For instance, the British Am-
phitha rubricata, which is a brilliant
crimson colour, builds a nest of particles
of seaweed cemented together with
threads; while another species of the
same genus (A. littorhia) makes a tube
by cementing together the edges of a
leaf of growing weed, so as to make
a tube open at both ends. Again,
according to Bates, Podoacerus capil-
latus " builds its nest in a very bird-
like manner in submarine forests ; the
nests consist chiefly of fine thread-like
material, woven and interlaced, being
established firmly in the branches of
zoophytes ; some small extraneous frag-
ments are often bound with it, but these
intention. The form of the nest is
These nests are evidently

gigantic andania, Andania gigantea (nat. size).

appear more the result of accident than

somewhat oval, the entrance being invariably at the top

used as places of refuge."

In the tribe Caprellina the head has coalesced with the first segment of the
thorax, and the abdomen is reduced in size, with most
of its appendages wanting. The two principal families
are the Caprellidai, or skeleton -shrimps, and the
Cyamidce, or whale-lice. In the former the thorax is
cylindrical, and the abdomen, with its limbs, rud-
imentary. In the typical Caprella the third and
fourth thoracic segments are without legs, but bear a
pair of branchial vesicles ; the appendages of the
second pair are developed into claspers, and those of
the three last pairs are of the ambulatory type.
These shrimps seldom swim, but climb amongst the
branches of seaweeds and zoophytes. When at rest,
they grasp the stems of the weeds with their hind-
limbs, and, holding the body in an erect position, wave
their long antennae in search of prey. In the whale-
lice, which live parasitically upon cetaceans, the short
and conical head is united to the first segment of the
thorax, which consists of six free, flattened segments.

As in Caprella, the third and fourth segments of the body bear no limbs, but are
furnished with a pair of gills, usually turned over the animal's back. In the

skeleton-shrimp (somewhat

enlarged).

AMPHIPODA.

79

female, these segments carry beneath them plates, forming sacs, for the eggs. The
second, fifth, sixth, and seventh segments are provided with short limbs, termin-
ating in a sharp, pointed segment, which closes against the
enlarged penultimate segment as the blade of a pocket-
knife closes on its handle. By means of these chelate
appendages the animals fasten themselves to the skin of
cetaceans, thrusting their sharp claws into the epidermis,
and adhering so firmly as to be able to withstand the dash
of the waves. '

The members of the tribe Hyperina differ from the
last by the larger size of the head, the more prominent eyes,
and the absence of a palp on the maxillipedes. To this
tribe belongs the large Cystosoma, a pelagic animal, probably
retiring during the day to a considerable depth, but occasion-
ally coming to the surface. The animal is colourless and transparent, so that by
transmitted light the internal organs can be seen. The head is large and inflated,
with its upper surface occupied by two enormous eyes. The genus Phronima also
contains species attaining a considerable size, examples of the European P. sedentaria

WHALE-LOUSE, Cl/aVlV.3

(nat. size).

transparent ocean-shrimp, Cystosoma neptuni (reduced).

phronima (enlarged three times).

280 CRUSTACEANS.

exceeding an inch in length. As in Cystosoma, the second pair of antennae are
obsolete; the head is large, with the eyes placed upon its summit. There are

seven pairs of large thoracic appendages, the third
from the end forming a large and strong pincer.

The species are widely distributed, although
most abundant in the tropics. Like many pelagic
animals, they are translucent, and mostly live in the
mantle - cavity of the ascidians Pyrosoma and
Doliolum, where the eggs are laid, and the young
hatched.

To a certain extent connecting the Malacostraca
with the Entomostraca is a group of Crustaceans
known as the Leptostraca, and containing the three recent genera Nebalia,
Nebaliopsis, and Paranebalia, and a number of fossil forms. The affinities of
the group seem to lie with the Phyllopods on the one hand, and the Schizopods
on the othei". The body is laterally compressed, and the whole of the cephalothorax
and the first four segments of the abdomen enveloped in a carapace, which springs
from the head, and is formed of two movable valves, closed by a muscle. Although
the eight thoracic segments are overlapped by the carapace, they are distinct and
movable. The abdomen consists of eight movable segments, or two in excess of the
normal number ; but there are only nineteen pairs of appendages. The head bears
a small, movable rostrum, and a pair of stalked eyes. The two pairs of antennae
are well developed, and there are three pairs of jaws. The appendages of the thorax
are foliaceous. The members of this group are marine, and widely distributed,
being found in cold and warm latitudes. The female carries the eggs attached to
her thoracic feet.

Subclass Entomostraca.

The Crustaceans of this division are small, and vary much more than the
Malacostraca, from which they differ in the following features. The number of
body-segments is not constant, but either greater or less than nineteen, and, as a
rule, there are no appendages to the abdomen. In the majority of cases the young
are hatched as a Nauplius.

The Barnacles, — Order Cirripedia.

The adult members of this group are so unlike typical Crustaceans that it can
hardly be a reproach to the older naturalists that they failed to discover their
affinity. Two well-known members of the order are the barnacles so frequently
attached to the bottoms of ships or floating timber, and the acorn -barnacles
covering the rocks on the coast. The barnacle {Leilas) consists of a tough longer
or shorter stalk, one end of which adheres tightly by means of a cement to the
timber or ship, while to the other is attached an oval compressed body encased in
pieces of shell, through two of the valves of which can be protruded six pairs of
slender, bristly, two-branched, filamentous limbs. These limbs, being the appendages
of the thorax, keep up a constant sweeping motion, whereby particles of food are

BARNACLES.

281

washed into the mouth that lies below them. The abdomen is undeveloped ; but
the rest of the body is enveloped in a fold, or mantle, supporting the outer shelly
skeleton. The jaws consist of two pairs of maxillae, and a pair of mandibles, and
the lower part of the head is inferiorly continued into the stalk, which contains
the gland secreting the cement. If a barnacle be carefully removed from its point
of attachment, the remains of the first pair of antennas may be observed on the
adhesive surface. When first hatched, the young are in the Nauplius stage, being
furnished with a median eye, and three pairs of appendages, of which the posterior
two are branched. After swimming for a while by means of these appendages,

BARNACLES ATTACHED TO PUMICE.

the larva moults several times, and passes into a second stage, in which, with its
two eyes and compressed carapace, it resembles a Daphnia. The rudiments of the
six pairs of thoracic legs appear behind the mouth, and the first pair of swimming
appendages become antenniform, each being provided with a sucker. By means
of these suckers the larva fixes itself to its permanent resting-place, and, the cement-
gland pouring out its secretion, glues the creature firmly to its point of attachment.
Hence it follows that the fixed end of the stalk is the front extremity of the body.
In the allied stalkless barnacle {Megalasma) the shell is attached directly to the
support. We are thus led on to the acorn-barnacles (Balanus), in which the entire
animal is enclosed in a shell formed originally of six pieces, which grow into a
tube of variable length. Some of the latter group (Balanidce), namely, the genus

28^

CRUSTACEANS.

acorn-barnacle (nat. size).

Coronula, or coronet-barnacles, attach themselves to the skin of whales. The

burrowing-barnacle (Tubicinella) has the same instinct. When adult it is long

and cylindrical,
consisting of a
stout, stony rod,
marked with a
series of annular
ridges. This is
buried deeply in
the skin of whales,
sometimes pene-
trating as far as the blubber.

These Cirripedes are not true par-
asites, inasmuch as they do not extract
nourishment from the animal to which
they are attached ; but many members
of the group live exclusively upon other
living beings, and nourish themselves at
their expense. One form, for instance,
Proteolepas, is in the
adult condition a
maggot -shaped,
limbless, shell - less
body, living within
the mantle-chamber

of other members of the same order ; while the root-headed Cirripedes (Rhizocephala)

live parasitically upon the higher crustaceans. They

are degenerate forms, possessing neither appendages

nor segments, the body being a mere sac, devoid of

alimentary canal, and absorbing nutriment by means

of the root-like processes branching throughout the

body of the host.

Bivalved Group, — Order Ostracoda.

This order is a small assemblage, characterised by
the possession of a bivalved shell, formed from the
right and left halves of the carapace, and furnished
with an elastic hinge to separate the valves and a
muscle to keep them shut. The shell encloses the
body which is unsegmented, has a rudimentary
abdomen, and bears seven pairs of appendages,
namely, two pairs of antenna?, three pairs of jaws
each belonging to the head, and two of limbs attached
to the thorax. These limbs, however, arc stout and
narrow, and, as a rule, there are no special respiratory

STALKLESS BARNACLE (nat. Size

PARASITIC CIRRIPEDE,

Sacculina (nat. size).

PARASITIC BARNACLES.

Upper Figure — Peltogaster curvatus
(enlarged 1| times) ; Lower
Figure — Xauplius larva of Par-
thenojoea (enlarged 200 times).

OSTRACODA AND COPEPODA.

283

organs. Ostracods occur both in fresh water and the sea; the best known
forms being Cypris and Cythere. The former contains species found in ditches
and ponds in England. When the waters in which they live dry up, the
species of Cypris bury themselves in the mud until rain falls; the eggs, which
are spherical, being attached to aquatic plants. The species of Cythere are mostly
marine, haunting rocky pools on the coast, and crawling amongst the seaweed.
In Cypridina, on the contrary, which is also marine, the animals dart about
with velocity ; the females carrying their eggs between the valves of the shell
attached to their feet.

Oar-Footed Group, — Order Copepoda.

In the free-living members of this group, the body is elongate and segmented ;
the thorax bears four or five two-branched swimming-feet, and the abdomen is
without appendages. A common fresh-water form is Cyclops, the structure of
which serves as a type of that of the order. The body is broad in front and
tapering behind, being thus pear-shaped in outline. The normal live pairs of head-
appendages are well developed, the first pair of antennae being long and acting as
oars. The dorsal elements of the head are fused to form a carapace, which bears
a single eye in front and is behind united to the first
thoracic segment, the remaining five of this region
being free. The abdomen consists of four narrow
cylindrical limbless segments ; but the last bears a pair
of processes severally tipped with a tuft of four long
bristles. The eggs are carried by the mother in a
couple of oval sacs attached to the last segment of the
thorax, and so prolific are these creatures, that a
female, it has been calculated, will in a year produce
over four thousand million young. The young when
hatched is an oval Nauplius (b), which gradually
acquires the characters of the adult. Closely resem-
bling the preceding is the marine Cetochilus, which
is devoured in large quantities by whale-bone whales.
a bright red colour, and when seen in myriads give the sea the appearance of being
stained with blood.

The Copepods hitherto noticed are spoken of as the Eucopepoda, but we now
come to a number of genera which have taken to a parasitic life, these Epizoa,
or Parasitica, being strangely unlike the higher forms. As one of the least
modified types, may be mentioned the carp-louse (Argulus). Of the more
degenerate types, the structure is exemplified in the annexed cut. In these the
body may be broad and flat, as Caligus (e\ which is frequently found upon the cod-
fish and the brill, or long and worm-like, as in Lemceonema and Pennella (a and c),
the former being a common parasite on the herring and sprat, while in Lerncea, the
gill-sucker, to which Hcemobaphes (d) is allied, the body is swollen and twisted in
the form of the letter S. The two long processes represented in the figures
projecting from the posterior end of the body are the egg-sacs. The appendages

COPEPODS.
a, Female Cyclops, with egg-sacs ;
b, c, Nauplius and later larva
of same.

These crustaceans are of

CRUSTACEANS.

of the head and thorax are more or less reduced, being either absent or converted
into adhesive hoops or suckers.

ri

a, Lerneeonema (enlarged 3 times) ; b, lirachiella (enlarged 9 times) ; c, Pennella (enlarged 5 times) ;
d, Hcemobaphes (nat. size) ; e, Caligus (enlarged 3 times).

Order Cladocera.

The members of tiiis order take their names from the large and branched
antennas, which serve as swimming organs. They are all small, and the carapace
forms a bivalve shell enclosing the greater part of the body, this carapace being an
extension of the dorsal surface of the head-segments. An example of the order is
the water-flea (Daphnia pulex), to which Acdnthocercus, represented in the
figure on p. 285, is nearly allied. Here the body is narrowed in front, and at
the posterior end, where the carapace (S) is deeply notched, is the tip of the
abdomen (C), bearing the pair of rigid barbed setse, from which the genus

CLADOCEKA.

285

takes its name. At the front of the head (A) is a large compound eye (O),
and the branched and plumed appendages projecting from beneath the sides of

spiny-tailed water-flea, Acanthocercus (much enlarged).

the head are antennae (R, T). The first pair of antennae are small and simple.

The jaws consist of the mandibles and the first pair of maxillae, the second

pair of maxillae being obsolete in the adult. The

thorax comprises five segments, each bearing a pair

of leaf-like swimming-limbs. The abdomen consists

of three segments and is limbless. The males of

Acanthocercus are smaller than the females and

much rarer, being generally met with in the

autumn. Eggs are laid both in summer and winter

and are passed into a brood-pouch, separating the

upper surface of the thorax from the backward

extension of the carapace. Here the summer-eggs

hatch, but the winter set are enclosed in a kind of

capsule developed from part of the carapace. This capsule, called the ephippium,

is cast off with the next moult of the mother's integument, and falling to the bottom

of the water gives exit to the embryos, which hatch in its interior. Another type

is the glassy Leptodora hyalina, so called on account of its semi-transparency, which

inhabits the open water of fresh-water lakes. The shell is so much reduced as

scarcely to envelop the animal.

EGG-CAPSULE OR Ephippium OF WATER-
FLEA, Acanthocercus (much enlarged).

2 8 6 CR USTA CEANS.

Leaf-Footed Group, — Order Phyllopoda.

Some of the members of this group are relatively large, the body being long
and composed of a great number of segments, of which the thoracic, and sometimes
the abdominal, are furnished with leaf -like gill-bearing appendages.

w

the glassy leptodora, Leptodora hyaliiia (enlarged 12 times;.

scale-tailed apus, Lepidurus (nat. size).

PHYLLOPODA.

2S7

In the family Apodidai, containing the genera Apus and Lepiduras, the anterior
end of the body is covered with a carapace, projecting from the head over the free
segments of the thorax. The hinder border of this
carapace is deeply cut out, and near its front end there is
a pair of contiguous compound eyes. The mouth is
bounded in front by a large upper lip and behind by a
deeply cleft metastoma, or lower lip. Both pairs of
antennae are short. The jaws consist of a pair of
mandibles and two pairs of maxillae ; these are followed
by eleven pairs of thoracic limbs, and there are append-
ages on the abdomen, sometimes numbering as many as
fifty-two pairs. The last segment of the abdomen bears
a pair of long filaments, and sometimes, as in Lepidurus,
a distinct caudal plate. These crustaceans occur in the
fresh waters of most countries. They swim on their
backs, using the legs as paddles ; and the eggs are capable
of surviving long periods of drought when embedded in
dried mud. In the second family — the Branchipodidce
— the body is also elongate, but there are no appendages
to the abdomen, which consists of nine segments, while
there are eleven pairs of thoracic appendages. The head-
shield is not developed backwards, and the large separated
eyes are supported upon distinct stalks. In the male, the
second antennae are converted into claspers. These forms

likewise swim upside down. Some {Branchipus) occur in a MALE 0F jjranchijms grwbei
fresh waters, but others (Artemia) prefer briny pools and (nat size) ; b, female of

m • -i • , t -i -i •11 1 1 j. 1. Branchipus qrubei (nat. size) ;

nourish in water so strongly charged with salt as to be e> MAJ 0/BBtt4 sheim;;

fatal to Other crustaceans. Artemia salina (enlarged).

Class Prototracheata.

This term is applied to the group now claiming attention, because in many
respects it occupies a place between the Tracheates and Worms, and is consequently
regarded as allied to the ancestral form from which all Tracheates have been
evolved. Unlike the true Arthropods, the limbs are not jointed ; and the tough
integument is covered with bristle - bearing papillae, but is not divisible into
segments. The long body is shaped like that of a caterpillar or slug, and to the
sides of its lower surface are attached a number of short more or less conical legs,
each tipped with a pair of strong claws. The head is supplied with a pair of stout
longish antennae, at the base of each of which, on the outer side, is an eye. On
the lower surface of the head is placed the mouth, supplied with fleshy lips and
two pairs of toothed horny jaws ; and on each side of the head there is a modified
appendage known as the oral papilla. The chief features to note in the internal
organisation are the presence of segmentally arranged kidneys — one opening at the
base of each leg — and the wide separation of the two strands of the ventral nerve-
chord. This last character is found in some of the lower worms, and the numbers

288 CRUST A CEANS.

of paired kidneys in the higher members of the latter group. The class contains
only the single family Peripatidce, which has a wide but somewhat singular dis-
tribution. The genus Peripatus, for example, is spread' over the West Indian
Islands, ranging from Nicaragua through the northern parts of South America to
Chili, and has also a single representative in Sumatra; while Peripatopsis is
confined to Cape Colony, and Peripatoides to Australia and New Zealand. These
three genera are easily distinguishable by external characters, and differ both
in internal features, and also in embryonic development. Nevertheless, all the
species seem to be closely similar in habits, living beneath the bark of trees, in the
crevices of rotten stumps, and under decaying leaves, but always in damp localities,
being exceedingly susceptible to drought. Locomotion is slow, and effected entirely
by the legs, the body being kept rigid ; and in walking every inch of the track is
carefully explored by the antennae, which are so sensitive that they seem able to
learn the nature of an object without actual contact. The sole function of the
eyes seems to be to distinguish light from darkness, though it is possible that
being nocturnal the animal may be able to see to a slight extent in a subdued
light. When irritated, these creatures spurt from their oral papillae a quantity of
slime at the offending object, and with the same sticky substance entangle their
prey, which consists of small insects. A specimen of Peripatopsis capensis has
been seen to overcome a small scorpion by this means. This slime — secreted by
two long glands extending from the oral papillae far back into the body — can be
ejected to a distance of about a foot. Curiously enough it will not adhere to the
skin of the Peripatus itself. In one of the Australian species {Peripoioides
oviparus) the mother lays her eggs in damp spots ; but, as a rule, the young are
born alive, and although the mother takes no special notice of them they crawl
upon her back for protection.

R I. POCOCK.

Peripatus edwardsii (nat. size, from life).

CHAPTER VIII.

Stone-Lilies, Star-Fishes, Sea-Urchins, and Sea-Cucumbers,
Subkingdom ECHINODERMATA.

Characteristics The star-fish, the sea-urchin, the brittle-star, the feather-star, and
of the Group. the sea-cucumber — especially the three former — are well known to all
frequenters of the seashore ; while the fossil sea-urchins of the Chalk, whose flint-
casts are so common on the downs of England, the so-called screw-stones found
in the Mountain Limestone, the pentremites and crinoids, whose remains are so
abundant in some parts of North America, are no less familiar to dwellers inland.
Though these animals differ much from one another in shape, a slight scrutiny
will discover many points in which they resemble one another and differ from
other creatures. They and their relatives are, therefore, placed in one great group
of the animal kingdom, the Echinodermata, — a group corresponding in importance
to the Molluscs, or the Vertebrates. This group is, in fact, more clearly defined,
and more widely removed from other groups than either of the two mentioned.
If a star-fish, or any of the animals named above, even a sea-cucumber or
holothurian, be touched with the finger, its skin will be found to have a rough
surface ; this is due to the circumstance that it contains a crystalline deposit
of carbonate of lime. In a sea-urchin, a brittle-star, or a feather-star, this deposit
is in the form of little plates, which build up a more or less rigid test ; whereas in
the star-fish it usually forms a kind of scaffolding, between which there stretches
the more yielding, leathery skin. In the ordinary sea-cucumbers the deposit
consists only of small spicules, which roughen the outer surface, and grate when
the skin is cut with a knife. If a thin slice of the skin of one of these animals be
cut and examined under a microscope, the spicules may easily be seen lying in
its middle layer. It is this same deposit that forms the spines of a sea-urchin and
the stalked column of a crinoid ; and it is this which has enabled so many of the
Echinodermata to be beautifully preserved as fossils. To this character is due the
name of the group, derived from the Greek, echinos, a hedgehog, and derma, skin.
Many animals have some deposit of lime, such as the shells of the Molluscs, and
the bones and teeth of the Vertebrates, but the deposit of the Echinodermata
differs in two characters : first, that its microscopic structure is that of a mesh-
work, or rather of a beam-and-rafter work, since it is deposited in the spaces
of a network of soft tissue ; secondly, that each element, whether a spicule or
a plate, is, despite its trellised structure, deposited around regular lines of
crystallisation. Owing to these characters, the minutest portions of an
echinoderm skeleton can be recognised, even when fossilised. This tendency of
the Echinoderms to deposit lime is not confined to the skin, the walls of the
vol, vi. — 19

290

ECHINODERMS.

internal organs being often strengthened by a deposit of similar structure.

Although, as has been said, each element of the skeleton follows the laws of

the typical crystallisation of carbonate of lime, yet the structure of the trellis-
work varies greatly, and is often character-
istic of the species in which it occurs.
Thus, the species of sea -cucumber can be
distinguished by the shape of their spicules ;
and the same is said to be the case with
those sea-urchins that deposit spicules
among their viscera.

The next feature noticeable is the
radiate structure, in many cases giving to
the animal a star - shape, to which the
common names star -fish, brittle -star, and
the like are due. The ordinary red star-
fish, or cross-fish, of the English coasts has
five distinct rays, or arms ; and this number
five, to a greater or less extent, controls
the arrangement of the organs in the
majority of the Echinoderms. It can be
detected even in a sea-cucumber or holo-
thurian, where, beside the feathery tentacles
of the head, are rows of shorter sucker-like
processes, which extend the length of the
body; these rows being five in number.

a, Tentacles round the mouth ; e, Anchor- and plate- The internal organs, as will be seen later

shaped spicules : b, c, d, Similar spicules of an , ™ , , . ,,

allied form. on> are variously attected in the various

classes of the Echinoderms by this five-
rayed symmetry. A radiate arrangement is not, however, confined to Echino-
derms, as it also occurs in jelly-fish and sea-anemones. Hence those animals
were once grouped with the Echinoderms, under the title of Radiata. But, if a
sea-cucumber or a sea-urchin be opened, there is a marked distinction between
it and a jelly-fish, in the presence of an intestine, shut off from the rest of the
body-cavity, and often coiling round inside it. In this respect the Echinoderms
resemble all the animals that have been dealt with in the preceding pages,
whereas the jelly-fish and their allies differ from them in having no body-cavity
separated off from the stomach and its processes. Moreover, Echinoderms resemble
the higher animals in the possession of a system of branched tubes conveying blood
through the body.

Examining a star-fish or a sea-urchin, one sees, on the under surface of the rays
in the former, and passing in five bands from top to bottom of the latter, a number
of small cylindrical processes, which are usually gently waving about like trees in
a wind. They lie in each band, or in each ray, along two rows, with a clear space
between, like trees on either side of an avenue ; hence the whole band of them in
each ray is called an ambulacrum (garden- walk). Most of these little processes
end in sucker-like discs, which the animal can stretch out and attach to smooth

anchor sea-cucumber (Synapta),

GENERAL CHARACTERS.

291

surrounding objects ; and it is thereby able either to hold itself firm against waves
or currents, or to pull itself along. Hence these processes are usually called

SEA-CUCUMBERS AND A BRITTLE-STAR.

292

E CHINODERMS.

tube-feet; but sometimes they end in a point, and cannot assist in locomotion,
though they may help respiration, when they are sometimes called tentacles.
If a single foot be touched, it immediately shrinks up, and if the touch be
vigorous, the adjacent tube-feet probably follow its example. Tube-feet torn from
the animal sometimes continue their waving motion, showing that this is, partly
at least, due to muscular action. Their movements are also caused by the squeezing
of a fluid into them ; for each foot is like an indiarubber tube closed at the end,
and passing through the test (as the shell of the sea-urchin is termed) to join with
one main tube, which runs along under the ambulacrum in a radial direction ; and
before it joins this radial canal, each tube-foot gives off a small swelling likewise
filled with fluid, so that when this swelling is contracted all the fluid is squeezed

up into the foot, and pushes
it out like the linger of a
glove when blown into. The
radial canals pass along under
the ambulacra till they join
in a ring -canal surrounding
the mouth. Eventually this
circular canal is connected
with the surrounding water
by a canal passing right
across the body - cavity to
the other side of the animal,
near the vent, where it opens
to the exterior through a
plate pierced with a number
of pores. This plate is called
the madreporite,and the canal
leading to it — owing to the
limy deposits formed in its
walls — the stone-canal. This
whole system of fluid-filled
canals is termed the water- vascular system. The foregoing description refers to
its arrangement in a star-fish, or regular sea-urchin ; but the system occurs, with
various modifications, in all Echinoderms, and is one of the features that separate
the group from other animals.

The Echinoderms are also peculiar in the possession of three, or perhaps four,
different systems of nerves, of which three, or at least two, are present at the same
time. One system supplies the skin, the tube-feet, and the intestine ; its chief parts
being a ring round the mouth, and radial nerves radiating therefrom. The second
system has a similar arrangement, but lies deeper, and supplies the internal
muscles of the body-wall. The third system, which is most fully developed in
crinoids, starts from the other side of the body, opposite to the mouth, and supplies
the muscles that work the arms and stem. If the arm of a star-fish be opened
from the back, there will be seen a pair of pleated extensions from the stomach.
If these be removed, there will be exposed a pair of orange-coloured tubes, some-

DIAGRAM OF AMBULACRAL SYSTEM OP A STARFISH.

/, Small swellings connected with the tube-feet ; k, The radial canal with
which they unite ; e, Ring-canal into which the radial canals open ;
c, d, Membranous sacs that serve as reservoirs for water from radial
canals ; a, Stone-canal, leading from ring-canal to the madreporite,
n ; m, Mouth.

GENERAL CHARACTERS. 293

what branched and knotty, which communicate with the exterior at the angles
between the rays. These are the generative glands. In all Echinoderms, except
sea-cucumbers, these glands are affected by the radiate structure of the animals ; in
crinoids the generative products are even produced in the extremities of the arms.
Distinction of Having glanced at those points of structure in which Echinoderms

the classes, resemble one another and differ from the rest of the animal kingdom,
we may shortly examine the main characters in which a sea-urchin, a star-fish, a
crinoid, a brittle-star, and a sea-cucumber differ from one another. First may be
noted obvious differences in form and in position in the living state. In an ordinary
sea-cucumber (as shown in the illustration on p. 291) the body is cucumber-
shaped, with the mouth at one end and the vent at the other ; between these run
the five ambulacra, one or two of which are often more developed than the others,
so that the animal crawls along on that side of its body, with its mouth foremost.
A sea-cucumber has no arms or projecting rays, but its mouth is surrounded by a
circlet of tentacles, often branched, which can be retracted at will. A regular
sea-urchin, such as the sea-egg {Echinus), shown in a later figure, resembles
a sea-cucumber in being without projecting rays ; but it is more spherical in shape,
and moves with its mouth towards the sea-floor. On the other hand, in a heart-
urchin {Spatangus), which moves through and swallows mud and sand, the body
has become transversely elongate; that is to say, the long axis is at right angles
to the position it occupies in a sea-cucumber; the mouth having moved a little
forward, and the vent being transferred from the top of the body to its lower
surface, so that both the mouth and vent lie on the under surface, at either end
of the long axis. In a star- fish, as in a regular sea-urchin, the mouth is in the
centre of the under surface, while the vent is almost in the centre of the upper
surface, although absent in a few forms. The body is either markedly pentagonal
in outline, or more or less star-shaped. In the latter case it is said to consist
of a central disc extended into arms, as in the illustration on p. 304. The number
of these arms varies from five (Asterias) to over forty (Heliaster) ; but in each
species with more than six arms the number may vary slightly, although constant
during the life of the individual ; in Labidiaster, however, fresh arms grow
out even in the adult. A brittle-star (illustrated on p. 291) resembles a star-fish
in which there is a sharp distinction between arms and disc ; the mouth being
on the under surface, but the vent wanting. And whereas the arms of a star-fish
are simply extensions of the body, containing the generative glands and processes
from the stomach, those of a brittle-star are mere appendages to the body, with a
stout internal skeleton of separate ossicles, working on one another by well-
developed muscles, and containing only blood-vessels, water-vessels, and nerves.
The arms of the brittle-stars are nearly always five in number, though sometimes
there may be from six to eight. As in the star-fish, the arms are unbranched,
except in the family Astrophytidce, where they fork ten or twelve times, and
where the numerous branches interlace so as to form a kind of basket-work all
round the disc, whence these animals are called basket-fish, or medusa-head star-
fish. A crinoid (illustrated on p. 297) differs markedly from a sea-urchin, star-fish,
or brittle-star, in that the mouth faces upwards ; the vent being also on the upper
surface. This position is due to the fact that, so far as we know, all crinoids are

294

ECHINODERMS.

at some time of their lives attached by a stalk to the sea-floor, or some other object,
so that the mouth and vent naturally move up to that side of the body furthest
from the stalk. This fixed state of existence has also caused the development of
arms, five in number, but often forked many times, which arms stretch out from
the body on all sides of the mouth, and contain extensions of the nervous, blood-
vascular, water-vascular, and generative systems. The representatives of the tube-
feet are arranged along the sides of these arms, on their upper or oral surface, and
between them is a groove, which is lined at the bottom with cilia, or extremely
minute hair-like processes, that keep waving in the direction of the mouth, and so

GROUP OF STONE-LILIES (PENTACMNIDS).

maintain a constant stream of water towards the latter ; such water containing the
minute animalculae and fragments of decaying organic matter on which the crinoid
feeds. The extinct cystids and blastoids have their mouth in a similar position to
that of the crinoids, and for a similar reason, but have not similarly branched
arms. In the blastoids five grooves radiate down the body from the central
mouth, and from the sides of these grooves there spring small, jointed, but
unbranched processes, called pinnules. The stem of the blastoids is very short,
so that when the pinnules have been lost, as is usually the case, the five-grooved
body looks like a bud, whence the name of the class. It is difficult to describe a
cystid as having any definite shape, for the various animals to which this name is
applied differ greatly from one another in structure. Echinoderms are built upon

CYSTIDS. 295

one or other of the plans of structure just described. Moreover, the animals
formed upon any one of these plans are found to agree with one another and to
differ from the rest in yet other features. Hence zoologists have divided the
Echinoderms into seven classes, each of which is again divided into orders.

All Echinoderms live in the sea, where they find in solution the
lime-salts from which their skeletons are built. None have become
modified for a truly fresh-water existence, and in this respect they are peculiar
among animals; a few holothurians, however, are found in the mud of some
estuaries and brackish- water lagoons, while a star-fish (Asteracanthium) and a
brittle-star (Ophioglypha) occur in the brackish waters of the Eastern Baltic.
Neither can Echinoderms live on land, and though they may exist for a short time
out of the water when left by tides, still it is only in the water that they can
breathe or feed. In the sea, however, they have a universal distribution ; from
ice-bound seas to the Equator ; from shallow shore-pools to mid-ocean ; from the
surface to the abyss ; on rocky shores, sandy beaches, muddy shoals, and bottom
oozes, among the roots of the mangrove, or in the meadows of seaweed. This
universal distribution renders their study one of importance for the geologist,
especially as their calcareous skeletons are readily preserved as fossils. Their
remains are known from rocks of every age in which animals are known to have
existed, and even the spicules of sea-cucumbers have been found as far back as the
Carboniferous period. Moreover, the rapidity of evolution in the group, and the
short period of time during which any one species was in existence, combined with
the wide area of distribution possessed by many species, render these fossils of
great value for the correlation of strata in different countries.

The Cystids, — Class Cystidea.

The Cystidea have been extinct since the Carboniferous period. Not only
are they among the oldest animals, but there is reason to suppose that they
approach more nearly the primitive forms from which all the classes of the
Echinoderms were derived. Many have not that regularity of symmetry which
characterises later Echinoderms. Such forms as Echinosphoera, commonly called
the crystal-apple, are mere round balls composed of a number of plates in which
it is hard to see any arrangement. Some of them seem to have been unstalked,
while in others the stalk is quite short. The arms are short, and vary in number,
bearing but slight relation to the plates of the test. In some, however, such as
Glyptosphcera, the ambulacral grooves, though rather irregular, are five in number
and lie on the surface of the test, all meeting at the mouth, which is placed in the
centre of the upper surface. Other cystids seem to be composed of an irregular
number of plates ; but they have become more definitely radiate in structure.
Some, like Agelecrinus, are flat circular forms, which live attached by their under
side to the flat surfaces of shells, and which have five distinct ambulacral grooves
radiating from the central mouth on the upper side ; while others, like Mesites, —
which resembles Agelecrinus in the arrangement of its grooves, — were attached, if
at all, by only a small part of the under side. Yet other cystids are definitely
attached by well-developed stalks, and have their bodies enclosed by a limited

296 ECHINODERMS.

number of plates arranged in regular order. Some of these present a six-
rayed symmetry, such as Caryocrinus, while others are governed by a five-rayed
symmetry, such as Lepadocrinus and Porocrinus. Both of these groups have as
a rule better developed arms, which sometimes branch, and are usually five or
six in number according to the symmetry of the cup. Hence these forms are
much more like the crinoids than are the other cystids.

In other Echinoderms the rays with their numerous tube-feet help the
respiration of the animal, but these were absent or very slightly developed in the
cystids. There are, however, other structures that are supposed to have served
the same purpose. In some (Aristocystis) the plates of the test are pierced by
simple pores, while in others {Glyptosphoirci) these pores are in pairs ; but in either
case the pores are scattered irregularly over the body, and possibly gave passage to
minute tube-feet. The development of these and their concentration in certain
areas of the test would produce an arrangement not unlike that of other
Echinoderms. Other cystids have certain portions of the test pierced by slits
{Lepadocrinus), and it seems probable that these permitted the surrounding water
to pass in to the membrane, lining the interior of the test. These structures are
called hydrospires (water-breathers), and somewhat resemble the cribriform organs
found in some deep-sea star-fish of the present day (Porcellanaster), figured later
on. Structures called hydrospires have also been described in such cystids as
Caryocrinus and Echinosphcera ; but it is doubtful whether these actually sub-
served respiration, although the true hydrospires may have been evolved from
some such undeveloped structures.

Another point of interest in the cystids is the light they throw on the origin
of the crinoid stem, which is formed of a series of flat rings. The simple round
plates, with a circular hole through the middle, are often called St. Cuthbert's beads,
while those marked with five petals, so common in the Lias at Lyme Regis, have
been termed star-stones. Technically the two kinds are distinguished as Entrochi
and Astroites. They are familiar in the polished slabs of Mountain Limestone,
in which it may be seen how the long stem is formed of a number of these round
ossicles jointed together, and pierced throughout by a narrow canal. The ossicles
are joined by ligaments passing right through their solid substance, and endued
with slight muscular power ; the central or axial canal serving for the passage of
blood-vessels, which are surrounded by a sheath of nervous tissue that controls
the movements of the stem. By one end the stem is attached to the sea-floor,
either by a flattish encrusting extension of its calcareous substance, or by a number
of fine branches or rootlets, as in the root-crinoid (Rhizocrinus), herewith figured.
By the other end the stem is attached to the plates forming the cup enclosing
the body of the animal, and it is at this end that it grows, by the constant
development of new ossicles between the cup and the upper segments of the
stem. Now, if we suppose that the crinoids, like other Echinoderms, sprang from
sac-like ancestors with a number of irregular and small plates, it is difficult to
understand how such a stem was evolved ; but the mystery is elucidated by some
of the cystids and older crinoids. First, it may be noted, that in those cystids
possessing a crinoid-like stem, as well as in many of the older crinoids, the axial
canal of the stem is much larger than it is in later forms. Secondly, that in many

CYSTIDS AND CRINOIDS,

297

older crinoids, the ossicles of the stem, instead of being simple rings, are generally
composed of five equal parts. In other words, there are five radial sutures or
joint-surfaces, running the whole length of the stem and dividing each ossicle
into five parts. These sutures are more con-
spicuous towards the root end of the stem, which
was of course the first to be formed in each
individual. Thirdly, examination has shown that
in some of these stems, especially towards the root
end, the five portions of each ossicle do not lie
regularly above the five portions of the under-
lying ossicle, but alternate with them to a certain
extent, just in the same way as the circlets of
plates that make up the cup of a crinoid alternate
with one another. These facts alone would lead
us to suppose that the stem was originally com-
posed, like the cup still is, of a series of circlets of
small plates, five in each circlet, and alternating
with one another; that the stem was, in fact,
nothing more than a continuation of the cup,
with essentially similar structure. Turning to the
cystids, we may see how this view is confirmed and
extended. In certain forms, such as Trochocystis,
that part of the stem next the body consists of a
double series of alternating plates, which are thin
and enclose a large hollow. In Arachnocystis the
whole stem consists of four or five series of alter-
nating plates. In Dendrocystis, the plates forming
the upper part of the stem can only be distinguished
by their smaller size from those forming the cup ;
below they merge into the normal series of single
ossicles. Cigara is the name given to a stem
entirely composed of small irregular plates. We
may, therefore, conclude that the stem originated
as a portion of the body of the animal, elongated,
and gradually becoming more and more regular
in its structure. The curiously elongate and
irregularly plated form called Pilocystis may repre-
sent the earliest stage in its evolution, before one
can even say that a stem is differentiated at all.

The Stone-Lilies or Crinoids, —
Class Crinoidea.

LOFODEN EOOT-CRINOIDS (f liat. size).

The crinoids differ from the more highly
developed of the cystids in the greater regularity of their structure — the symmetry
of which is nearly always governed by the number five, — in the greater development

298 ECHINODERMS.

of the arms — which are often much branched, — and in the absence of special breathing-
organs, which were no longer needed. It is easy to see how an organism that is
fixed, and equally affected on all sides by the surrounding medium, whether air or
water, develops a radiate symmetry ; the same result being obvious in the case of
most flowering plants. Slight consideration will also show why the number five
has been favoured by these particular animals. The body of a crinoid is encased by
a limited number of relatively large plates, united together by the skin in which
they are developed, and it is clear that the sutures between these plates are lines
of weakness. Supposing that there were four plates in each circle, then the four
sutures would be in opposite pairs, and the lines of weakness would run right across
the body of the animal, which would easily be broken ; and the same result would
follow if there were six plates and three pairs of opposed sutures. Though the
test might be more flexible, still there would be three lines of weakness in each
circle instead of two. But when there are five plates, each suture lies opposite to
the middle of a plate, and so the line of weakness does not run right across the body.
A few crinoids have essayed other forms of symmetry, but none have had a long
existence. The alternation of the plates in a crinoid may be explained by similar
mechanical considerations ; for such an arrangement corresponds to the bonding of
successive courses of bricks in a wall. There is reason to suppose that the ancestors
of all crinoids, as well as most of the Palaeozoic crinoids, were attached to the sea-
floor or some other object throughout life by the stem. On hard rocky bottoms the
attachment was by means of an incrustation, as in the pear-encrinite (Apiocrinus)
of the Bradford Clay ; but on oozy bottoms the end of the stem broke up into
numerous branches called cirri, as in the Rhizocrinus of modern seas. In course
of time these cirri were developed, not only at the root end, but also higher
up the stem, and eventually they came in some genera to be arranged in regular
whorls of five,, as we see them in the living Pentacrinus. Since crinoids were
at all times liable to be broken from their attachment, some of them gradually
acquired slight faculties of locomotion, although they prefer to renew their
attachment, even though this be transferred to some other object. Sometimes the
whole end of the stem coiled itself around the stem of another crinoid, but usually
it became anchored by such cirri as chanced to remain on the preserved portion.
In those crinoids that have the cirri in whorls, the ligaments that unite the joints
of the stem stop short just below each ossicle bearing a cirrus, so that the division
between this ossicle and the one below yields readily to a bending or blow ; and
thus the crinoid can anchor itself easily by the whorl of cirri left at the end of
its broken stem. In some cases there is developed at the end of the stem a little
ball of calcareous tissue, serving as a weight to keep the animal right way up, as
it moved slowly through the water by the waving of its arms; and in certain
forms this ball developed spines, directed upwards like the flukes of an anchor,
and serving the same purpose.

The stems of most crinoids have no great power of bending or coiling, since
the ridges and ligaments are distributed equally all over the joint surfaces.
Writing of pentacrinids, dredged in the Caribbean Sea, Professor Agassiz says:
" They move the cirri more rapidly than the arms, and use them as hooks to catch
hold of the neighbouring objects, and on account of their sharp extremities they

CRINOIDS.

299

are well adapted to retain their hold. The stem itself passes slowly from a rigid
vertical attitude to a curved or even drooping position." Other crinoids, like
Herpetocrinus, have, however, a single fulcral ridge running across the surface of
the joints, allowing far more play between the latter. In Platycrinus the joints
had an elliptical outline, and the fulcral ridge formed the long diameter of the
ellipse. Such a structure would naturally give the stem great power of bending,
but only in one plane. This restriction was got over by giving the joints a slight
skew, so that the stem was twisted like a corkscrew and capable of movement in
every direction. In Rhizocrinus the same end is attained by each joint being so
twisted that the fulcral ridge at the top
is at right angles to the one at the
bottom. These types are, however,
merely side branches from the main
stem of crinoid evolution; the chief
advance having proceeded along the
lines of free locomotion. At various
periods forms have existed, which,
having once tasted liberty, have gradu-
ally dropped all traces of their former
attachment. Thus, Agassizocrinus of
the Coal-Measures is a crinoid that has
nothing left of its stem but a solid knob
at the base of the cup; Millericrinus
of the Great Oolite has been found at
all ages and stages of development, the
young individuals with a normal stem
which gradually withers as the animal
gets older, till in full-grown specimens
it is a mere tapering process. Uinta-
crinus and Marsupites from Cretaceous
beds, are two genera as unlike in
essential structure as crinoids well
could be, but resembling one another in
having thin-plated large cups, without
the smallest relic of a stem. A little

crinoid of Jurassic age called Thiolliericrinus appears, however, most nearly
related to, if it be not the actual ancestor of, most of the free-moving unstalked living
forms. It seems to have been related to Bourgueticrinus and Rhizocrinus, but,
like Millericrinus, gradually dropped its stem, while the upper joint of the stem
coalesced and began to bear cirri. In the common feather-star (Antedon) of the
British seas this process has gone yet further ; the animal breaks away from its
stem when quite young, but retains the uppermost swollen and coalesced segments
of the stem, which form one solid mass bearing a number of cirri, while the two
lower circlets of cup-plates almost entirely disappear, so that only the upper circlet
of plates, from which the arms arise, remains. The Antedonidce, which have all
arisen since Jurassic times, include not only numerous species of Antedon, but at

MEDUSA-HEAD PENTACEINID.

a, Crown and part of stem (nat. size) ; b, Upper surface of
the body, the arms broken away, showing the food-
grooves passing to the central mouth.

3oo

E CHINODERMS.

least as many more of a closely allied genus, Actinometra, as well as three other
less common genera, named Atelecrinus, Eudiocrinus, and Promachpcrinus. They

are far more numerous
at the present day than
the stalked crinoids, and
occur in all parts of the
world, but their head-
quarters are in the
Eastern Archipelago.

There are a few
crinoids that have
diminished their stem,
but have nevertheless
remained attached, so
that at last the cup has
come to be fixed on the
sea -floor without the
intervention of a stem.
Such a form is the
stumpy and thick -set
Holopus, whichis among
the greatest rarities in
museums. It lives at
depths of about a
hundred fathoms in the
Caribbean Sea. Similar
forms occur in some of
the shallow-water and
reef deposits of Jurassic
and Cretaceous age.
Many of these have
become a little unsym-
metrical and bent over
in one direction ; which
may, perhaps, be ac-
counted for by their life
on reefs, where food is
brought to them by
currents flowing only
in one direction.

Next to the stem,
the most characteristic
structures of a crinoid
are its arms. Each arm starts from one of the five plates that form the uppermost
circlet in the cup. The arms are said to be radial in position, and those plates from
which they start are specially distinguished as the " radials."

ROSY FEATHER-STAR, CLINGIXG TO A TUBE OF SABELLA WORM

(nat. size).

In many forms, such

CRINOIDS. 301

as Cyathocrinus, the upper edge of each radial is notched by a horseshoe-shaped
facet, provided with a transverse fulcral ridge and muscles, so that a regular
articulation is formed for the working of the arm up and down. In such forms —
known as Inadunata — the arms are quite separate from one another and are easily
distinguished from the plates that compose the cup. But in the forms to which the
names Flexibilia and Camerata are applied, smaller plates are developed in the
spaces or interradii between the arms, and these additional plates bind the arms
together and so incorporate them in the walls of the cup. A crinoid of this kind,
such as Actinocrinus or Uintacrinus, has therefore a much larger body than a
Cyathocrinus or Pentacrinus. Sometimes the arms form part of the cup without
the intercalation of interbrachial plates ; while yet other plates may be developed
between the forks of the arms themselves. In the Flexibilia the plates that form
the cup are rather loosely joined to one another, so that there is some play between
them ; the arms also have much power of motion. In the Camerata the plates are
more firmly united, and additional fixity is given to the cup by the strengthening
and solidification of the upper surface around the mouth. In the Inadunata and
Flexibilia the grooves on the inner surface of the arms, which convey food to the
mouth, pass over this upper surface of the cup, and are merely protected by the
ordinary small plates that can be opened or shut down over them. But in the
Camerata the plates of this upper surface of the cup have become so thick and
welded together, that the grooves are no longer open, and even in some cases have
been pressed down beneath the surface, underneath which they form regular
tunnels. The mouth too is no longer visible on the upper surface. Crinoids of
this type were most abundant in the Carboniferous period, and it is to a large
extent their remains that make up the masses of Derbyshire marble.

Among curious modifications of arm-structure may be mentioned the Silurian
Crotalocrinus. Here the arms are forked many times, but all the separate
branches are joined together at their sides, so that the arms when outspread form
a single net. In Petalocrinus of the same age this process has been carried so far
that the branches of each arm are solidly fixed together, and the crinoid appears to
be provided with five paddles. In Uintacrinus the ten arm-branches reached the
enormous length of 3 feet, and seem to have been capable of movement in various
directions, so that the swimming powers of the crinoid must have been greatly
enhanced. Saccocoma, which lived in the still lagoons where the Solenhofen litho-
graphic stone was deposited, had a very light body and long, fine arms, provided
with flat oar-like processes.

The locomotion of the free forms is effected by the raising and depressing of
alternate arms, and the movements of these arms are correlated by the peculiar
nervous system that has its headquarters at the bottom of the cup. This
swimming has been observed in both Antedon and Actinometra kept in an
aquarium. As a rule, however, these animals remain attached by their cirri to
rocks, to the bottom ooze, to seaweeds, or to other marine animals. In this
position the arms are outspread, and the small branches or pinnules that line their
sides are kept slightly waving. If the water be ruffled, the first impulse of the
crinoid is to flatten its arms out suddenly and to hold on to the rock or other
object with its pinnules. The pinnules of an Antedon can be bent in any direc-

3o2 ECHINODERMS.

tion ; those near the extremity of the arm being specially active. If its extremity
be touched by any irritating substance, the arm is erected at right angles to the
upper surface of the animal and so removed from the other arms, while the pinnules
move something like the legs of a fly that is cleaning itself. If, however, this
proves ineffectual, the arm bends over to the one on the opposite side, the pinnules
of which then assist in the operation. The pinnules move in this manner to dis-
embarrass the arm of fragments of foreign matter that are too large ; but the
hooks at the end of the pinnules can catch and retain minute fragments, which, as
they decay, attract animalculse, and so furnish food for the animal. If a stimulus
be applied to any point on the under surface of the animal, the arms on the side
from which it comes are simultaneously and forcibly pressed down, apparently to
create a current that shall wash away the irritant. If an arm be cut off, it will
continue to move for a short time. The crinoid, however, flattens its remaining
arms, and rests immovable for half a minute ; it then slowly crawls in a direction
away from the wound. Antedon does not appear to like the light, and if placed
on the surface of a stone in a glass vessel, always prefers to crawl to the under
side, where it remains fixed by its cirri. If, however, a strong light be reflected
on to the under side of the stone, while the top is kept dark, the animal will crawl
back to the top. It is by crawling that the crinoid usually moves from place to
place. The arms on the side towards which it intends to move, are stretched out ;
the pinnules are curved backwards towards the body, like so many grappling-hooks ;
and the arms are then curved up in S-fashion, thus dragging the animal along.
Meanwhile, the arms of the opposite side move in the converse way, and their
pinnules are directed away from the body, so that they push instead of pull.

At the present day crinoids live in all seas at depths between fifty and three
thousand two hundred fathoms ; but they prefer clear and undisturbed waters.
The same has been the case in former geological periods, for while crinoids are
abundant in limestones, of which their own remains form large masses, they are much
rarer in sandstones and shales. As in the case of the well-known pear-encrinite,
colonies of crinoids that lived in clear water have been suddenly overwhelmed by
an influx of mud, which first killed and then preserved them. Unstalked as well
as stalked crinoids live chiefly in colonies ; but this is due less to sociability than
to limited powers of motion even in the larval state. In the older rocks,
individuals of many different genera and species may be found that lived in close
association. In the later periods it is more usual to find numerous individuals of
the same species in association ; examples of such colonies among stalked crinoids
are Rhizocrinus in the North Sea and off North America, Baihycrinus in the
Southern Ocean, Pentacrinus off Portugal and in the Caribbean Sea, and
ExtracriniLS in the Lias of Lyme-Regis.

The food of crinoids consists chiefly of foraminifera, diatoms, and the adults
of small and the larvae of larger crustaceans. Crinoids themselves form food
for fish, though nowadays their place seems to be taken by the brittle-stars and an
occasional sea-urchin. As protection against such attacks, some crinoids have
been provided with spines, either as movable processes from the plates of the
test, as in Dorycrinus from the Carboniferous of North America, or, very rarely,
movably attached like the spines of a sea-urchin, as in Hystricrinus from the

BLASTOIDS.

3°3

Devonian of the same country. Parasites, however, find crinoids an easy and
almost unresisting prey. A suctorial crustacean, eggs and all, has been found in
the body - cavity,
while a decapod
crustacean occasion-
ally inhabits the in-
testinal tube. The
annexed figures re-
present the cysts
formed by the crinoid
in response to the
irritation set up by
the presence of a
parasitic worm, in
which cysts it takes
up its abode. There
are also worms that
bore into the stem, as

well as boring sponges, and corals that affix themselves to the stem. The crinoid
generally makes some attempt to overwhelm these intruders by the rapid deposition
of the calcareous skeletal substance ; so that in the rocks greatly thickened stem-
fragments are found enclosing the remains of corals, brachiopods, etc.

SWELLINGS IN THE PINNULES OF CRINOIDS PRODUCED BY A

parasite (twice nat. size).

The Blastoids, — Class Blastoidea. ,

The Blastoidea constitute a compact group, pretty clearly marked off from
both Cystidea and Crinoidea, which they resemble in the upward position of the
mouth and the generally fixed habit. The chief character that separates blastoids
from other echinoderms is the presence of an elongate plate, the lancet-plate,
underlying the ambulacrum and pierced by a canal supposed to have contained the
radial water-vessel. These five canals meet in a circular canal round the mouth,
but there is no evidence that they were connected with tube-feet as in other
echinoderms. Each side of each ambulacrum was lined by a row of delicate,
unbranched arms ; and the food-grooves of these arms passed to a single groove
running down the middle of the surface of the ambulacrum, and these five grooves
then passed up to the mouth.

The most interesting structures in the Blastoidea are the hydrospires. In such
a form as Pentremites there are five openings (spiracles) round the mouth, placed
in the interradial areas between the ambulacra. From each of these spiracles, a
canal passes under the test in a direction away from the mouth. This canal soon
branches, and a branch goes to the side of each ambulacrum. Each branch of the
canal swells into a pouch with thin walls that are strengthened by a slight deposit
of lime ; and these walls are thrown into folds so that their surface is increased.
There is thus a folded pouch running along the inside of the test under each side
of an ambulacrum ; and from this pouch short tubes are given off which open to
the exterior through pores at the sides of the ambulacrum, which pores alternate

3°4

ECHINODERMS.

with the arms and are not in any "way connected with them. These hydrospires
are clearly quite different structures to either of the two kinds of structures that
go by the same name in the Cystidea. They have been compared with certain
structures in the Ophiuroidea. In the latter animals are oval pouches, which lie at
the sides of the arms where they spring from the body or disc, and which open to
the exterior by slits. Their walls are strengthened by calcareous rods, and into
them the ovaries open, so that developing young are often found in them, as in the
marsupium of a kangaroo. They are known as genital bursse, but their folded
inner walls probably serve to bring the outer aerated water closer to the internal
organs of the body, that is to say, their function is in part respiratory. We may,
therefore, fairly suppose that the hydrospires of Blastoids served primarily for
respiration, possibly in place of tube-feet, and secondly for the maturation and trans-
mission to the exterior of the generative products. All blastoids have not
hydrospires of precisely the same structure as those above described, since in some
they are more like the slits previously mentioned in Lepadocrinus and Porocrinus;
while they are always in the same interradial position, which is not the case with
the cystids.

The Star-Fishes, — Class Asteroidea.

With the Asteroidea we come to echinoderms that differ from those hitherto
described, and resemble those to be dealt with, in that none of them are fixed, but all
are free-moving, and in the fact that the mouth is not directed upwards. There is,

however, reason to be-
lieve that these free
forms are, like the free
crinoids, descended from
ancestors that were
fixed ; and in the young
Aster ina, at all events,
there is a prolongation
of the forepart of the
body, which not only
corresponds in position
to the prolongation that
becomes the stem in
crinoids, but actually
serves for a short time
as an organ of attach-
ment. But whereas in
the crinoid the mouth
moves upwards to the
surface opposed to this
organ of attachment, and there becomes surrounded by arms, which similarly face
upwards, in the asteroid the mouth and its surrounding arms are bent downwards
so as to face the sea-floor, and the animal, instead of collecting its food from the
water above, extracts it f rom the mud below. Correlated with this mode of life, the

BLUE CHINA STAR-FISH (nat. size).

STAR-FISHES.

3°5

vent and madreporito are on the upper side of the body. So little is known of the
Palaeozoic star-fishes and their relations to later forms, that all classifications must
be regarded as provisional. Subdivisions have been based on the character of the
so-called pedicellariae. These are small pincer-like organs that occur in star-fishes
and sea-urchins, on the surface of the test, as shown in the illustration below.
The movable spines covering the surface of these animals, and varying in size from
minute, delicate, bristle-like structures to long rods, which may be thin and
pointed, or thick, or even globular, are familiar to all. The pedicellariae are
probably derived from the smaller spines; two
of these united at the base by a muscle, and
slightly curved so as to approach one another
at the ends, form the simplest kind of pedicellaria ;
and, by gradual modifications of this type, all
the varieties may be derived. Many uses have
been ascribed to the pedicellariae, such as holding
pieces of food, or removing dirt from the surface
of the test. In some sea-urchins they are pro-
vided with poison-glands, which seems to show
that they serve as weapons of offence in those
cases. It has been considered that in sea-urchins
their chief use is to catch hold of fronds of
seaweed and keep them steady until the spines
and tube-feet can be brought into action. The
inner surfaces of the forceps in the pedicellariae
are remarkably sensitive, and the blades close on
any minute object immediately their inner sur-
faces are touched by it. It seems, however, that in spite of the amount of attention
devoted to these organs, we do not yet understand all their uses. Besides spines
and pedicellariae, star- fish also have on the surface of the skin small tubular
processes, containing an extension of the body-cavity. These have very thin, con-
tractile walls, and doubtless serve to assist respiration. All star-fishes have tube-
feet, but in some these have no suckers at the end, and in all cases those which are
at the ends of the rays are used only as feelers, and are stretched in the direction
in which the animal is moving. At the extremity of each arm is a single tube-
foot, which is the first to be formed, and is known as the unpaired tentacle ; this
being always stretched straight out. Immediately above this tentacle is a small
eye, coloured by red pigment, and protected by small tentacles.

Star-fish are sluggish animals, rarely moving of themselves, and staying for
days in the same position. Those kept in tanks or in glass vessels prefer to cling
to the side, instead of lying on the bottom. When disturbed, however, a star-fish
can travel at a considerable pace. Those star-fish that have suckers crawl by means
of their tube-feet, while those that have no suckers still use their tube-feet slightly,
but also progress by the muscular movements of the rays. The short-armed
Asterina and Astropecten can right themselves in less than a minute, and accom-
plish the act by raising themselves on the tips of four rays, and then turning a
somersault by throwing over the fifth ray. Asterias takes rather longer, and

vol. vi. — 20

PEDICELLARIA.

a, Two-jawed, closed ; b, Two-jawed, open ;
c, Three-jawed. (20 times nat. size. )

3°<5

ECHINODERMS.

effects its purpose by first twisting, over one or two of the rays and catching hold
of the ground by the suckers. It then gradually, turns, over the rest of the body.
Cribrella rights itself in the same way as Asterias, but, apparently because of the
stiffness of its skeleton, takes much longer over the process. Star-fish, like other

echinoderms, are a sociable class.
Even the deep-sea forms sometimes
live in swarms. Many shallow- water
forms also are gregarious, and some
species have been observed to pair at
the breeding- season. The deep-sea
star - fish, writes Alcock, " subsist
largely on molluscs, the shells of
which, along with the chitinous
remains of prawns and amphipods,
are often to be found in their
stomachs ; but some of the character-
istic deep-sea forms appear to gorge
themselves with globigerina-ooze."
The shallow- water forms prefer hard
ground, rocks, reefs, or beds of hard
sand, where they find in abundance
the molluscs and small crustaceans
on which they feed.
Between the Asteroidea and Ophiuroidea, the family Brisingidw has been
considered by some a link ; but in all essential features of structure they agree
with the Asteroids. Superficially they resemble the Ophiuroids in having long,
thin, flexible arms, clearly distinguished from the small central disc or body.

STAR-FISH TURNING OVER.

The Brittle-Stars, — Class Ophiuroidea.

The name Ophiuroidea, given to the brittle-stars, refers to their long serpent-
like arms, which are attached to a relatively small and usually rounded body or disc.
The digestive and generative systems do not extend into the arms, but are confined
to the body ; so that the arms are appendages to the body, rather than portions of
it. They are cylindrical, and have no groove on the under side, such as exists in
star-fish, but have little openings through which the tube-feet pass. In this class
it is the arms themselves, and not the tube-feet that are used for locomotion. The
tube-feet accordingly have no terminal suckers, but are very sensitive to touch,
and probably assist respiration. The greater part of each arm is formed by a
central axis of successive calcareous segments, not unlike the vertebras, of a back-
bone. Each arm-ossicle or vertebra is, however, composed of two parts, one on
either side, and united in the middle line ; the successive ossicles being connected
by pairs of strong muscular bundles, and articulating with one another by tenon-
and-mortice joints. According to the degree of development of these joints, the
arms have varied powers of coiling. ; Thus, in the Cladophiurce, the ossicles have
more or less saddle-shaped faces, so that the arms can be twisted round foreign

BRITTLE-STARS.

3°7

objects or rolled towards the mouth ; in the Strejrtophiurcc, the faces of the ossicles
have slight pits and processes, but none sufficient to prevent the ossicles being so
twisted on their neighbours that the arms may be rolled up towards the mouth ; in
the Zygophiurce, the faces of the arm-ossicles have articulating knobs and pits,
which prevent the arms from being rolled up towards the mouth. These vertebral
arm-ossicles are encased in the tough outer skin of the arm, in which are developed
granules, plates, and spines, which are least definite and regular in the Gladophiurm,
most definite in the Zygophiurce. The spines, which are clearly shown in the
annexed figure of Ophiotkrix, are borne on the side-plates of the arm, and aid the
animal in locomotion. The integument of the disc also bears plates or scales of
various sizes, often more or less covered
with granules and minute spines. The
precise arrangement of the plates on the
top of the disc varies in different species ;
but five pairs of plates, known as the radial
shields, are always present at the base of
the arms, and are shown in the annexed
figure. On either side of the arms where
they join the disc, there is seen on the under
surface a slit-like opening. These openings,
known as the genital slits or clefts, are
usually single but sometimes double ; they
lead into thin- walled pouches or bursse at
the sides of the rays. In a living ophiurid,
the disc alternately expands and contracts,
and thus water is pumped into and out of
the pouches, through the slits. The enter-
ing water brings oxygen, which it ex-
changes, through the thin walls of the
pouch, for the carbonic acid contained in
the water of the body -cavity, and then
goes out again by the return current.
Hence the pouches are called respiratory

bursee. But they have another function, since the ovaries enter into them, and the
ripe ova may either be carried out by the current through the slits, or they may
remain and undergo direct development in the pouches themselves. Around the
mouth are a number of short flat processes, or papillae, serving as strainers, and
keeping foreign bodies that are not wanted for food from entering the stomach.
Round the mouth are also twenty tentacles, which are really the modified tube-feet
of the two first arm-segments of each arm. They are in a state of continual move-
ment, assisting the food to enter, and clearing away the undigested residue, which
is ejected from the mouth.

The branched ophiurids, or Cladophiurce, are sedentary, attaching themselves
by coiling their branching arms around corals and suchlike animals ; but can move
when they please. The same mode of life is also affected by a few of the simpler
forms ; but, as a rule, ophiurids have considerable powers of locomotion, of which

COMMON BRITTLE-STAR (3 liat. size).

3o8

E CHINODERMS.

they readily avail themselves. Most walk rather than creep, raising themselves
on their five arms as upon legs ; stretching out one or two arms in front, and
drawing the rest of their body in the same direction. Even in a state of repose,
the arms alone touch the ground, the disc remaining raised above it In other
forms, however, the rays of the body undulate laterally, and produce a creeping
serpentine movement. Rondelet wrote that the common brittle-star creeps by the
nexuous movement of its rays in the manner of serpents, and, placed on dry land,
never ceases to move them, until it casts them off in pieces, which, although
separate, move by bendings, like parts of worms and the cut-off tails of lizards.
The little Amphiura, which lives under stones, among the roots of seaweed,
can turn its arms very quickly around its disc, and so form itself into a little
ball ; thus, if it be disturbed, it can roll and sink quickly into deeper parts of the
water. Sometimes ophiurids are seen to progress by a kind of rowing motion of
the arms.

The Sea-Urchins, — Class Bchinoidea.

The sea-urchins are the best known, as they are the most numerous of all
echinoderms. The annexed illustration shows the test or shell of the egg-urchin,
with the spines on the right side, but scraped away from the left. The plates of
the test are seen to be covered with rounded tubercles of various sizes, and it is to

these that the spines are attached by
a ball-and-socket joint, surrounded by
muscles that can move the spines in
any direction. The tubercles do not,
however, cover the whole test indis-
criminately, but are disposed chiefly in
five broad zones, extending from one
pole to the other. Alternating with
these are five narrower zones, bearing
smaller and fewer tubercles, and pierced
by small holes arranged in regular rows.
Through these holes pass the tube-feet,
which are all provided with suckers
at the end. These latter zones are,
therefore, the ambulacral zones ; one
of them being seen in the middle of the illustration. The other zones are called
interambulacral, and one of them is shown on the left of the same illustration. All
the zones converge towards the summit of the test, where the vent is situated
in a circular space covered with membrane. This membrane contains a few
irregular granules, and is surrounded by five large interradially placed plates,
pierced by the ducts of the generative glands. One is also pierced by a large
number of small water-pores, and is called the madreporite. Outside these five
plates, and alternating with them, are five other plates, each situated at the top of
an ambulacral zone, and pierced by the unpaired tentacles, which terminate the
water-canals, and represent the unpaired tentacles near the eye at the ends of the
arms of a star-fish. At the other pole of the body is another membrane, sur-

TEST OF EDIBLE SEA-URCHIN, WITH THE SPINES REMOVED
FROM THE LEFT-HAND HALF (nat. size).

SEA-URCHINS.

3°9

jaws of stone-urchin (nat size).

rounding the mouth-opening, through which may be seen five pointed teeth.
These belong to a very elaborate masticating apparatus, shown in the illustration,
and found in all the regular urchins, as also in the Clypeastrida among the
irregular urchins. This consists of twenty principal pieces arranged into a five-
sided conical mass, compared by Aristotle
to a lantern (a). In the centre of the
whole are five teeth (6, c), working in
bony sockets, or pyramids, connected by
muscles with one another, with the interior
of the test, and with the arched processes,
known as auricles (d), that surround the
mouth - opening. There are yet other
calcareous pieces connecting the pyramids
together, and serving as attachments for yet other muscles. Such a sea-urchin
as that described, preserves as much as any echinoderm the five-rayed symmetry
of the group ; but in many forms the five-rayed type is not so obvious, for the
animal has become elongated along one of the axes, so as to have a superficial two-
sided symmetry. This is naturally connected with constant movement in one
direction, as though the animal had a head and tail ; and such modification is found
among those urchins that live on muddy bottoms, and especially in those from
considerable depths. Not only is the test elongated, but the mouth moves forward

to the front margin, and the vent down-
wards to the hinder margin, so as
eventually to lie on the under instead
of on the upper surface of the test. An
earlier stage in this modification is
shown in the illustration of the shield-
urchin (Echinarachnius), and a fully
developed one in the heart -urchin
(Brissopsis), with its long tube -feet
extended in the act of walking towards
the left. These heart-urchins, as they
move along through the sand and mud,
scoop it up into their mouths, and pass
it through the intestine, extracting on
its passage such nutriment as the
minute organisms it contains can afford.
To enable them to scoop it up in this
way, the hinder margin of the mouth
is produced forwards in a kind of shovel shape, as is shown in the illustration of
a Pourtalesia test from which the spines have been removed. These animals live
at very great depths in the sea, and are the urchins most modified in this particular
direction. Urchins of the heart-shaped type have short delicate spines, and move
almost entirely by their long tube-feet, in the manner described ; but the greater
number of the regular urchins progress chiefly by the aid of their spines, which
are much stouter, while the tube-feet often have the suckers very imperfectly

SHIELD-URCHIN, FROM ABOVE (nat. size).

3io

E CHINODERMS.

developed. The spines of sea-urchins also serve as organs of protection ; but their
efficacy varies much in different forms. For instance, Diadona setoswm has fine
sharp spines, 8 or 10 inches long, which prick one almost before one, can see them, and
can pierce the stoutest boot ; their danger being increased by the gregarious habit
of the animals. Some sea-urchins have poison-glands attached to their spines.
It is the smaller spines that are protective, and they are placed for this purpose
near the main openings and organs of the body, such as the vent, genital pores,
and eyes; they also protect the ambulacra, and bases of the larger spines. A
Porocidaris feeling itself free from danger, in well aerated water, walks from
one side to the other, doubtless in search of food ; its ambulacral tentacles being

FIDDLE HEART-URCHIN, MOVING OVER THE SAND TOWARDS THE LEFT (nat. size).

stretched out as feelers, and its long spines moving as described. The smaller
spines are depressed to permit of the free movement of the larger ones, and those
of the ambulacra raised to permit the extension of the tube-feet. If one slightly
wounds the animal when thus expanded, the larger spines immediately stiffen on
their tubercles, while all the smaller spines depress themselves, each over the
organ that it is destined to protect. Though the tube-feet may not be used for
locomotion, they are put to another useful purpose. If a Strongylocentrotus be
placed in a tank with some dead shells or similar objects, it will raise them on to
its back, and hold them there by means of the tube-feet, as a kind of concealment.
Some sea-urchins cover themselves all over in this way with bits of seaweed, shell,
and small pebbles, and so move about unobserved. Other sea-urchins do not move

SEA-URCHINS.

3'i

from place to place, but always stay in one spot, where they are generally found
living in a hole. Sometimes the hole may have been there before the sea-urchins;
sometimes may have been formed by the growth of calcareous algae around the
sea-urchin ; but sometimes the urchin itself has bored the hole. This is accom-

phial-shaped pourtalesia ; test with spines removed (enlarged 4 times).

plished not by any acid secretion, — for on the west coast of Africa an Echinometra
has been found boring into an augite lava, — but by the continuous movement of the
teeth and spines. The common Strongylocentrotus is a well-known example of a
boring sea-urchin. When the waves wash up against the urchin it sets its spines
rigidly against the sides of its hole and so holds fast.

Although most of the sea-urchins have a rigid test, yet there are some in
which the plates are only loosely joined together, so that the test is flexible.

leather-urchin (§ nat. size).

This is the case in an Astropyga; but is still more pronounced in the leather-
urchin (Asthenosoma), and other members of the family Ecfiinothuridce. Re-
spiration is effected in the regular sea-urchins by ten gills near the mouth.
These are thin - walled ciliated extensions of the body - cavity protruding

3i2 ECHINODERMS.

between the membrane round the mouth and the plates of the test. In the
irregular urchins some tube-feet are modified for respiration, becoming broad,
flat, and somewhat lobed ; the hinder end of the intestine seems to be respiratory
in function. Some sea-urchins possess eyes. In a Diadema there are five
ovate pigment-masses of a brilliant ultramarine blue, placed at equal distances
around the vent. There are certain other peculiar bodies supposed to be sense-
organs of some kind, called sphseridia, which are of microscopic size, and in
structure not unlike tiny spines. They lie near the mouth and on the lower
ambulacral plates, are often set in small holes, and are provided with special nerves.
Perhaps they test the water in which the sea-urchin lives, and thus may be said
to serve the sense of smell. Sea-urchins are both animal and vegetable feeders,
and are even cannibals when opportunity offers.

The Sea-Cucumbers,— Class Holothuroidea.

Sea-cucumbers are, as we have seen, elongated and worm-like creatures, with
a mouth at one end and a vent at the other. The skin is leathery, and
contains a comparatively small amount of calcareous matter. Usually this
occurs in small spicules, which assume very definite shapes, such as the anchors of
Synapta, or the wheels of Chiridota; but in such forms as Psolus the spicules

increase in size, so as to form a plated integument.
There may also often be a ring of calcareous plates
round the gullet, five of which plates have the same
relation to the radial water- vessels as the auricles around
the jaws of a sea-urchin, and they likewise serve for the
attachment of muscles. In such a common form as
Cucwmaria planci there are five rows of tube-feet pass-
ing from mouth to vent. The five-rayed symmetry is
not obscured, and is traceable in the arrangement of
nerves and muscles, although it does not affect any
portion of the digestive or generative systems. Around
(3 nat. size). the mouth, in Cucumaria, is a fringe or branched

tentacles, connected with the water- vascular ring. In
most other echinoderms, it will be remembered, a canal passes from this ring and
opens to the exterior by a madreporite ; and in a few holothurians of primitive
structure this is similarly the case. But in Cucwmaria, as in most, the connection
with the exterior is lost, and the canal, with its madreporite, hangs down into the
bocly-cavity. In Cucwmaria the tentacles are used like a net to intercept floating
organisms in the surrounding water. Many holothurians swallow a great deal of
sand, and the intestines of those that live near coral-reefs generally contain
fragments of coral. They usually attach themselves by their tube-feet to rocks
or seaweed, and wave the tentacles around. Holothuria atra, which lives on the
great Australian barrier-reef, inserts its hinder extremity within a crevice of the
rock, into which on being disturbed it speedily retreats.

Some curious modifications of form have taken place among the holothurians.
In the plated sea-cucumbers (Psolus), of which a specimen is illustrated on p. 314;

U-SHAPED SEA-CUCUMBER

SEA-CUCUMBERS.

3X3

the animal has become flattened, and the tube-feet restricted to three out of the
five ambulacra, and by these three the animal creeps about, or holds itself fixed to
the rock. A similar modification is carried to excess in the deep-sea holothurians
known as Elasipoda. Here, as in the illustrated Scotoplana, there are a couple of
rows of thick tube-feet, forming little stumps, with which the animal moves, as a
centipede moves by its legs. In front there is a sort of funnel or scoop formed by
the short tentacles, while a few of the tube-feet form long horns or feelers on the
upper side. In the deep-sea Psychropotes, on the other hand, mouth, vent, and
tube-feet are confined to a flat sole; while the posterior part of the body is

a deep-sea holothurian, Scotoplana (nat. size).

extended in a long tail. Some holothurians live in mud; and by reason of
constantly keeping both mouth and vent above the surface their bodies have
become curved in U-fashion, as seen in the U-shaped Ypsilothuria (illustrated on
p. 312). This is carried still further in the club-like Bhopalodina (illustrated
on p. 314), a form shaped like a cherry, with a thick stalk ; the openings of both
mouth and vent being at the top of this stalk. A yet stranger modification is the
holothurian described under the name Pelagothuria, which lives in the East
Pacific, on the surface of the ocean. It has no calcareous spicules, the longitudinal
muscles being mostly changed into a jelly tissue. Around the mouth the body is
extended into a kind of disc, prolonged into thirteen to sixteen feelers. The
animal swims by the movements of this disc.

Holothurians have no means of offence, but protect themselves for the most
part by assuming the colour of their surroundings. The huge Synapta besseli,
which reaches a length of 6 feet, has a habit, when taken in the hand, of squeezing
the fluid contents of its body towards the portion that is grasped, till it becomes
too big to hold. Some, when much irritated, seem to fade away and dissolve by

3H

ECHINO DEEMS.

breaking
a part of

\

up their tissues; while others have an objectionable habit of shooting out
their intestines in long viscous strings ; and it is owing to this that a

common British form has gained

the name cotton-spinner. It has

been suggested that this habit has

been acquired in connection with

the presence in the intestine of

small parasites, and these in their

turn have their habits affected

according as they live in holo-

thurians that are or are not

cotton - spinners. Among the

parasites of holothurians should

specially be mentioned a little

fish of the genus Fierasfer, that

inhabits the intestine of some

species, and has its food provided

for it by the holothurian ; this fish

is described on p. 438 of Vol. V.

Holothurians are of interest, as furnishing a food known

as trepang, which ranks with edible birds' nests among the

delicacies of a Chinese table. The

fishing for trepang, or beche-de-mer,

as the holothurians are called by

the Portuguese, takes place very

largely in Oriental countries, and is

being extended to the Barrier Reef

of Australia. All kinds are not

equally esteemed, for some have too

much calcareous deposit in their

skin, and others get rid of their

insides, and so become too lean.

CLUB-LIKE SEA-CUCUMBER (Rhopalo-

dina) (nat. size).

V DEEP-SEA HOLOTHURIAN,

Psychropotes (§ nat. size).

Development of Echinoderms

Few things about echinoderms are more remarkable
than their modes of reproduction, which include both a
sexual method, from the fertilised egg, and also one by
budding or splitting of a single individual into two.
Many echinoderms, as we have already seen, have the
curious power of breaking off portions of themselves ; as
the brittle-star or crinoid can break off their arms. Also
they are able to eject the whole or a part of their viscera,
a faculty which has been specially developed in some of
the holothurians. It is still more remarkable that the
portions so broken off can be grown again, and that they

A PLATED HOLOTHURIAN (Psolus).

Some plates of the back, above
the brood-pouch, are removed
(enlarged 3 times).

DE VEL OPMENT

3*5

themselves can, in many cases, grow fresh bodies, and become complete individuals.
A star-fish of the genus Linckia commonly avails itself of this faculty ; and it is
by no means rare to find big arms with a small body at one end, and four little
arms growing out of it ; these are known as comet-forms. This power of repro-
duction is probably due to the extension of all the systems of the body into the
arms : the arms of brittle-stars, which do not contain all the systems of the body,
have not been known to reproduce individuals. In some cases echinoderms have
been seen definitely to reproduce themselves by fission or splitting in half. Such
division is well known to take place among the sea-cucumbers ; and it is believed
by some to take place even in brittle-
stars; the specimens of the six-
armed green snake-star (Ophiactis),
shown in the annexed illustration,
being thought to represent the
result of such a process. The
specimen A consists of two almost
similar halves ; but the three arms
towards the bottom of the illustra-
tion, marked a, are smaller than the
others marked a, and indicate that
this half is the later grown. The
specimen B, which is seen from the
back, has only just separated itself
from its other half. The separation
appears to take place by a forcible
though spontaneous rent, and the
edges of the wound subsequently
grow together, and not merely heal
up but reproduce the lost parts of
the animal. As a rule, however,
echinoderms reproduce by the
ordinary sexual methods ; although
this, too, presents peculiarities. Just
as a butterfly does not develop
directly from the egg, but passes
through the intermediate larval stage of the caterpillar, out of whose chrysalis the
butterfly springs, so the sea-urchin or the star-fish egg gives rise to a larval form,
in whose body, as it were, the mature form is developed. The particular shape of
the larva varies in the different classes of echinoderms ; but the differences are not
essential, and it is clear that all the larval forms are modifications from one primitive
type. The changes passed through in the development of the common sea-urchin
{.Strongylocentrotus drcebachiensis) are depicted in the illustration on p. 318, in
which the drawings are very greatly magnified.

The fertilised egg divides and subdivides until a round ball of cells is formed.
This is then pushed in at one end, as one might push in a soft indiarubber ball,
so that there is formed a little sac with a double wall to it (stages 1, 2). Stage 3

green snake-star (enlarged 5 times).

316

ECHINODERMS.

shows this in outline as though transparent ; and one sees the opening a turned
downwards, and the canal d, which foreshadows the intestine. At the upper pole

DEVELOPMENT OF A SEA-URCHIN (stage 9).

DEVELOPMENT OF A SEA-URCHIN vStageS 1-8).

of the embryo, near the number 3, is a small
tuft of cilia, by the motion of which the embryo
swims about. In stage 4 this ciliated area is
seen to have extended downwards to the letter v.
The intestine now develops in such a way that
the original opening (a) remains as the vent, the
middle part (d) widens into a stomach, and a
fresh mouth-opening (m) is pierced through at
its upper end. This is seen from the side in
stage 4, and from the front in stage 5. But
before the mouth is formed, two ear-like pro-
cesses (w) show themselves, which are important
as being the beginnings of the ambulacral and
water -vascular systems. There also appear a
few delicate, symmetrically laced rods of car-
bonate of lime, which by and by grow into the
skeleton of the larva, in shape something like
an inverted easel. The two lower ciliated

DE VELOPMENT.

1*1

bauds now grow towards one another, so that the vent comes to lie beneath
them (stages 7 and 8). They also join themselves to the two upper bands, so
that there is formed a single zone of cilia, which persists to the end of the
larva's life. Already can be distinguished the beginnings of the apex and of the
processes (e), which finally lengthen into the arms that give such a strange
appearance to the larva, in the sea-urchins and also in the star-fish and brittle-

DEVELOPMENT OF A SEA-URCHIN (stage 10).

stars. In stage 8 can be seen, at b, the pore that admits water to the water-
vascular system ; and at this point will lie the madreporite of the future sea-
urchins. The next illustration shows all these parts in a rather more advanced
stage : a is the vent; c, the hinder intestine ; d, the stomach, around which a deposit
of spicules indicates the. first beginnings of the body of the sea-urchin; o, the gullet;
m, the mouth ; e, the arms of the larva : r, the calcareous rods that support them ; v,
two more strongly-developed and slightly projecting portions of the ciliated band ;
and w, the water-vessels. The larva in its full development is shown in the

3iS

ECHINODERMS.

illustration on p. 317, in which the letters have the same meaning. This larval
form is called a Pluteus, on account of its frequent changes of shape, as it swims
about with its arms constantly moving. It will be noticed that through the whole
of its development it retains a two-sided symmetry, such that if cut down the
middle it would be divided into two precisely similar halves. This is very different

from the five-rayed symmetry of the
sea-urchin, and the difficulties arise
both in this class and in the others
when we try to discover how the
live-rayed form was produced from
the two-sided one.

From this larva only the stomach
and the water- vascular system are
continued into the sea-urchin, whose
prickly body is now being formed
around the stomach of the larva;
and it is in just those two systems,
especially in the madreporite and in
the intestine, that we note in the
adult the traces of the primitive
bilateral symmetry. When the little
body of the sea-urchin, which at first
is like a flat box, has become pro-
vided with a mouth of its own, and
with a circlet of comparatively large
spines, then the parts not necessary
to the new structure disappear. The
calcareous skeleton of the larva is
absorbed, and the lime salts thus set
free help to build up the test of the
sea-urchin. The arms sink in, and
at last the outer larva remains as
nothing more than a skin over the
test of the urchin. The mode of life
of the little sea-urchin, about one
millimetre in diameter, is now com-
pletely altered. It is no longer
carried about through the water, but crawls by means of its tube-feet and its spines,
as shown in the above illustration. We cannot here follow the further changes
that it Undergoes ; but a study of those later stages is of great importance. For
by means of such study Agassiz has shown that many supposed genera are nothing
more than undeveloped forms of well-known species, and "he has thus been able
to work out the relations of speeies and genera to. one another. It is not, however,
all echinoderms that pass through these curious larval stages, for in many species
the young are developed in the shelter of the mother. We have already seen this
to be the case with many brittle-stars, which are protected in the so-called genital

YOUNG sea-urchin (Strongylocentrotus). a, From below ;
5. From above (enlarged 20 times).

DEVELOPMENT.

3i9

bursas. In a sea-urchin {Hemiaster philippi) there are depressions between the

ambulacra, which are called brood-pouches ; for in these the young develop from

the egg, covered over by the spines of the parent, as in the annexed illustration.

In some holothurians the young are

attached to the body of the parent, as in

Cladodactyla crocea ; but in others, as in

Psoitis ephippifer (shown on p. 314), they

live on the back of the mother under

some large mushroom-like plates. Some

star-fish, too, such as Pararchaster, have

a kind of tent of plates in the middle

of the disc, where the young grow up as

in a nursery.

The direct development from the
egg to the adult in these protected forms,
seems to show that the elaborate shapes
of the various larvae have been developed
secondarily for the special purpose of
transporting the young and aiding in the
dispersal of the species, and, therefore,
that they are not relics of any ancestral
forms. There can, however, be little
doubt that the echinoclerms were origin-
ally derived from some form or forms
with a two-sided symmetry; and it is
certainly curious what a close resemblance
their assumed primitive larval form
presents to the larva of Balanoglossus, the worm-like animal described on p. 573
of the last volume, and considered by many authorities to be in the ancestral line
of the Vertebrata.

F. A. BATHER.

brood-pouch of a sea-urchin (enlarged 5 times).

CHAPTER IX.

The Molluscs or Shell-Fish, — Subkingdom MOLLUSCA.

Science is. never stationary, and consequently the scope of many groups of the
animal kingdom has considerably altered since they were defined by their original
founders. Such has been the case with the Mollusca of Cuvier. Besides the
animals which constitute this subkingdom, as now understood, he included in it
the Tunicata, Brachiopoda, and Cirripedia — branches of the zoological system,
which more recent anatomists have long since removed elsewhere. At the present
time the Mollusca comprise only such forms as the octopus, cuttle-fish, etc., all the
marine shell-bearing animals of the whelk tribe, and other kinds, land and fresh-
water snails, slugs, the tooth-shells, and bivalves of every description. The number
of known species is very large, and fresh forms are constantly being discovered.
Probably some fifty thousand recent species have already been described, the
number of aquatic being more than double that of the terrestrial species. The
aquatic kinds, however, will eventually be found to preponderate still more, for the
sea appears to be inexhaustible in the production of new forms. It matters not
in what ocean the dredge is let down, be it to a great depth, or in shallower
water, something new is certain, sooner or later, to be gathered in. Drop the
dredge to three thousand fathoms (more than three miles), and still molluscs are
met with, and the extreme depth to which molluscan life extends has yet to be
ascertained. The great coast lines of South America, Africa, Asia, and parts of
Australia have been but imperfectly explored for the smaller kinds of Mollusca ; for
whenever a limited stretch of coast is carefully searched by the conchologist, con-
siderable numbers of new species are forthwith discovered. On the contrary,
with the terrestrial forms the case is different. They are more easily acquired, as
they come under actual vision, and all the inhabitants of a given district can in
course of time be known.

Molluscs are soft, cold-blooded animals, without any internal
Definition. . . . . „

skeleton ; but this is compensated for in the majority of cases by an

external hardened shell, which serves at once the purpose of bones and as a means

of defence. Their bodies are not divided into segments like those of insects and

worms, but are enveloped in a muscular covering or skin, termed the mantle, the

special function of which, in the majority of species, is the formation or secretion

of the shell. . Molluscs are more or less bilaterally symmetrical ; but this bilateral

symmetry in some cases, particularly among the Gastropods, is to some extent

obscured by the contortion of the body. The foot, which serves the purpose of

locomotion, or is used in burrowing in sand, wood, and rock, etc., is an organ

highly characteristic of most Molluscs. The shells, in the vast majority, consist

GENERAL CHARACTERS. 321

either of a single piece, as in the snail, whelk, etc., or of two portions (valves) as
in the oyster, cockle, and most other bivalves. In one group, however (Chitonidai),
the shell takes the form of a series of eight adjacent plates, and in one group of
bivalves (Pholadidce) there are one or more accessory pieces in addition to the
two principal valves. In the bivalves, with one or two exceptions, the shell is
always external. Not so with the univalves, in some of which it is quite con-
cealed beneath the skin, in others it is partially so. Shells are mainly composed
of carbonate of lime, with a small admixture of animal matter. Their microscopic
examination has revealed a great diversity of structure. Some are termed porcel-
laneous, others horny, glassy, nacreous, and fibrous. The shell is essential to the life
of the inhabitant, it forms part of its organisation, and if it be removed, death
ensues sooner or later. Although Molluscs have the power of repairing injuries
to their shells, no case is known of a species removed from its shell having secreted
a fresh one. Many shells exhibit an outer coat of animal matter termed the
periostracum. It is generally of an olivaceous tint, but varies considerably in
thickness and appearance. It is quite smooth, or of a velvety or silky aspect, or it
may be produced into hair-like extensions. Its special function is the preserva-
tion of the shell from atmospheric and chemical action. Were it not for the
periostracum, the shells of fresh- water molluscs would in time be dissolved by the
carbonic acid gas with which water is more or less saturated. Owing to the thin-
ness of the periostracum, or to its having been worn away, the apical portion of
many fresh- water spiral shells and the tips or beaks (umbones) of the bivalves are
frequently more or less eroded through this chemical action.

The shells of gastropods are enlarged with the growth of the
inhabitant by the addition of fresh layers to the margin of the
aperture, so that a shell which at its birth had only two volutions or whorls, may
eventually consist of about a dozen. The growth of bivalves is more readily
understood, being effected by additional concentric deposits along the outer margin
of the valves. The adult condition of many shells cannot be detected by a super-
ficial inspection. This is particularly the case with the bivalves. On the contrary,
a little experience soon teaches us to recognise in the majority of cases if a
gastropod shell is immature ; but even among this class there are many exceptions
where the most practised eye would fail to determine the period of growth.

Many shells exhibit conspicuous prominences on the surface in the form of
spines and ridges, and it is -a great puzzle to the uninitiated how this ornamenta-
tion is produced. It is, however, a very simple matter. Wherever a spine occurs
on a shell we may be certain that it resulted from a corresponding filament or
process upon the edge of the mantle, and these processes may be brought into use
only periodically. A striking example of this periodic formation of spines occurs
among the typical Muricidce. On the contrary, spines or extensions may occur only
upon the lip or edge of the aperture when the shell has arrived at maturity, and
consequently we may assume that the necessary prolongations upon the edge of
the mantle for the secretion of such spines are only developed at this period of
the mollusc's life.

The diversity in shells with respect to form, size, and solidity is simply
enormous. What resemblance, for example, is there between a Chiton and a

vol. vi. — 21

322 MOLLUSCS.

Dentaliwm, or a Carinaria and a Turritella, and among the bivalves between a
Pholas and the hammer-oyster {Malleus). The difference in size is still more
remarkable, some microscopic forms weighing not more than the fiftieth part of
a grain, whereas the gigantic Tridacna occasionally turns the scale at over
500 lbs.

As every mollusc has a history of its own, — a certain course to pursue in the
living world, — its means of existence and propagation will be found sufficient,
although to the human eye the chances against it may superficially seem over-
whelming. The glassy Carinaria, regarded as a dweller on the surface of the
ocean, would seem ill-adapted to withstand the buffeting of storms at sea ; and so
it is, but there is very little doubt instinct has taught the mollusc the proper
moment, and the sufficient depth to descend from the surface, to be safe from the
tempest's violence. The dweller on the seashore, open to the onslaught of the same
unpitying foe, defends himself with a stronger abode. What dash of the waves upon
the undefended rock could in the slightest affect the conical shell of the limpet ?
In very deep water the tendency to tenuity in the molluscan shell is plainly
apparent, yet there are species dwelling at depths beyond the influence of surface
storms, the shells of which present considerable strength and solidity. We may
ask how and why is this ? Although we may not in all cases be able to answer these
queries from actual knowledge, certain is it, that reasons, probably very near the
truth, are easy of suggestion. For example, the large Cyprina islandica and the
heart-cockle (Isocardia cor) of the British seas possess shells of considerable
strength and solidity. These, being molluscs of large size, would prove dainty
morsels to the hungry haddock or other fish, if they were unprotected by a power-
ful shell and their extermination thus prevented.

The varied colours of shells are due to glands situated on the
Coloration. . .

margin of the mantle. In most cases the colour markings are placed

on the outer surface of the shell, beneath the periostracum, but occasionally the
inner layer of porcellaneous shells is of a different colour to the outer. This is well
instanced in the helmet-shells (Cassis), which are employed by the carvers of shell-
cameos to produce white or rose-tinted sculptures upon a dark ground. The colour
in some shells is liable to extreme variation. Take, for example, the common
hedge-row snails, Helix nemoralis and H. hortensis. Here we find the ground-
colour yellow, brown, pink, white, lilac, and various intermediate shades, and the
bands which are usually brown, and normally five in number, may be altogether
absent or vary from one to six, their position also being equally variable. This
diversity in colour-markings results from the different position of the pigment-
glands upon the mantle margin, but the cause of this variation in the position has
not been ascertained, although it may be presumed ; nor is the reason known of
the difference of the ground-colour, which may occur among specimens of the same
colony. White, black, red, green, yellow, olive, purple, slate-blue, and brown form
the common ground-tints of shells, but pure blue is a colour hardly ever met with
in the shells of molluscs. One or two species of land -shells (Corasia) from the
Philippine Islands more nearly approach this tint than any other molluscs, but
even in these there is a slight admixture of green. On the contrary, blue is a
colour more commonly seen in the soft parts. The colour of the shell does

GENERAL CHAR A CTERS. 323

not necessarily correspond with that of the mollusc. The latter may be of
an intense black, the shell being quite white ; the " animal " may be a most
brilliant creature with a variety of many colours, and its test merely of some
uniform sombre hue. Very gorgeously painted shells are, however, generally
indicative of highly coloured inhabitants.

That light and warmth are great factors in the production of brilliant colour-
ing is beyond question. This is conclusively proved by the results of deep-sea
dredging. Whenever great depths are reached, where darkness reigns, and the
water is intensely cold, the molluscan inhabitants are without colour, or of very
sober tints, although the periostracum, generally greenish or olivaceous, is scarcely
modified under these circumstances.

Our information with regard to the duration of life in molluscs is
Age. .

very limited. Although certain species of land-shells have been kept

alive in confinement for four or five years, or even longer, we cannot assert that
they exist for so long a period under natural conditions. The length of life of
individuals, as well as of different species, is probably very variable, some doubtless
attaining to a good old age. Such a species as the giant clam (Tridacna), for
example, it is rational to conclude must have a very lengthy term of existence, for,
although the growth may be rapid, the formation of a shell weighing 300 or
400 lbs. must surely be the work of years ; and, moreover, when the process of
growth is ended, we know not for what period the shell may continue to live. It
is likely that most land-molluscs are full grown in a year or two, but the term
of their existence, after this, is probably very variable, according to the species. A
specimen of the common periwinkle has been kept in an aquarium for nine years,
but this scarcely indicates the limit of life of this species under natural conditions.
Its average duration may be longer, but probably shorter. In connection with
the length of life of molluscs, mention should be made of the long periods some of
the species are capable of existing without food in a state of torpidity.

In cold climates land-snails bury themselves in winter-time in the ground or
beneath dead vegetation, and in hot climates they assume a torpid condition in the
hottest and driest season of the year, closing up the aperture of the shells with a
temporary lid or door (called an epiphragm). Some of these summer-sleepers
display great tenacity of life, many cases being on record of species which have
lived for two, three, or even five years in a torpid state, without food of any
description. Perhaps one of the most interesting instances, is that which has so
often been quoted, of the specimen of the Egyptian desert- snail (Helix desertorum),
which was fixed to a tablet in the British Museum for four years, and was dis-
covered to be still living. Some fresh-water forms also are capable of living out of
their native element for a considerable time. A species of Australian Unionidce
has been known to exist out of water for over a year, and some kinds of Ampul-
laria have lived for months after being taken out of their native rivers.
Reproductive The sexes are distinct in some molluscs, and united in the same

system. individual in others, but reproduction is in all cases effected by means
of eggs. These are usually secreted or attached in some suitable position, but in
some instances the ova are hatched within the oviduct of the parent, as in the
fresh- water pond-snail (Vivipara); and probably in most bivalves the eggs are

324 MOLLUSCS.

retained within the parent shell until hatched. The ova of some of the gastropods,
enclosed in capsules, are deposited in masses, and some of these form very remark-
able and complicated structures. The number of eggs contained in some of these
clusters is enormous. As many as forty thousand have been estimated in a mass,
deposited by a single squid. The common whelk occasionally also piles up an
enormous heap of capsules, as many as five or six hundred being massed together,
each capsule containing several hundred eggs. Land-snails, in comparison with
marine forms, produce comparatively few eggs. Some of those deposited by the
large South American species are in a few cases half an inch to an inch in length,
and have a strong calcareous shell. On the contrary, the productive power of
some bivalves is enormous, the ova being counted not by hundreds but by hundreds
of thousands, and even millions. The ova of molluscs may be gradually developed
into the form of the adult, or there may be a free-swimming ciliated larval stage,
or a special larval form as in the fresh-water mussel.

Molluscs are both vegetable and animal feeders, but probably by
far the greater number of gastropods are carnivorous. Bivalves
imbibe a mixed diet of infusoria and microscopic vegetables. The carnivorous
species of gastropods principally attack other kinds of shell-fish, bivalves being
especially appreciated. Some however, like the common whelk, will feed on dead
fish and carrion of any description. Many of them are mere cannibals, and attack
their own kith and kin. Out on the high seas the glassy Carinaria enjoys the
succulent jelly-fish, and the squids and cuttles are a terror to many pelagic fishes.
The octopus, like the gastropods, is partial to a bivalve meal, and a repast on
shrimps and other crustaceans is a daily occurrence. Most land-shells are
herbivorous, but a few are carnivorous, preying chiefly upon their plant-eating
relations, and one curious slug lives exclusively on living earth-worms.

Most molluscs which are provided with a more or less distinct
head, namely, the cephalopods and gastropods, are furnished with
visual organs, but the majority of bivalves (Pelecypoda) are sightless. Although
an auditory apparatus exists, they appear almost insensible to sound. It is certain
that most forms are endowed with the sense of smell, although the anatomist has
frequently a difficulty in discovering the position of the olfactory organ. Land-
molluscs appear to recognise their proper vegetable food by the smell as well
as the taste, and the carrion-feeding whelks are probably attracted by odour. The
senses of smell and taste are probably but imperfectly developed in the bivalves,
which scarcely possess the power of selection as regards their food.

Molluscs exhibit various ways of progression. Some are free-
swimmers, like the cuttle-fishes and squids, pteropods, heteropods, and
a few bivalves ; others are mere crawlers, like snails and whelks ; and some creep
along, but beneath the surface of the water. The Melampus moves onwards after
the fashion of a looper-caterpillar, and the bivalves either crawl upon their foot, or
progress by a jerking or leaping movement. Many species, like the limpet,
Saxicava, and Pholas, are very sedentary in their habits, and others, which in their
early career are active, in after life are stationary in their permanent abodes.
Uses in Nature Molluscs form a large item in the food of many mammals, birds,

and to Man. reptiles, and fishes. Terrestrial forms are devoured by rats, ducks,

GENERAL CHARACTERS. 325

thrushes, and other birds ; by lizards, toads, snakes, and even by certain kinds of

carnivorous insects. The fresh-water forms are consumed in vast quantities by

water-birds of every description, by fishes, frogs, water-voles, and other mammals,

and aquatic creatures of various kinds ; and every seashore is constantly ransacked

by flocks of sea-fowl for the repasts of shell-fish it affords. Out in the depths

of the ocean many kinds of fishes, especially cod, haddock, gurnard, soles, and

mullet, are great devourers of molluscs, which ever fall a prey, not only to one

another, but also to crabs, holothurians, sea-anemones, and star-fishes ; and, finally,

among the pelagic pteropods the Greenland whale seeks his daily sustenance.

Molluscs of all kinds, but especially the marine species, are much eaten by the

natives of most countries ; and even in Europe, although the oyster is the most

highly appreciated, several other species are used as food. Molluscs are not only

of importance to man as an article of diet, but they are serviceable in other ways.

Their shells are employed as personal ornaments, and are used in the manufacture

of fishing-tackle by some uncivilised people. In England and other countries

many of the pearly species are manufactured into ornaments and various useful

articles, and the beautiful pearls themselves, secreted within the tissues of the

pearl-oyster, are esteemed as jewels.

The utility of the molluscs to man probably far outweighs the
Noxious Molluscs. . ... .

injury which is occasioned by a few kinds. In the foremost rank of

the noxious species stands the Teredo, the great destroyer of submerged timber.
The damage done to piers, boat-bottoms, and in fact to wood of any description
which is located in the sea, is enormous, and there seems to be no effectual means
of meeting the attack of these molluscs, except by covering the timber with metal-
sheeting. The stone - work of breakwaters occasionally becomes more or less
damaged by the burrowing habits of the Pholas and Saxicava. On land, snails
and slugs commit onslaughts upon our crops and gardens, but these pests are more
easily overcome than their marine relatives.

Although this is a subject very fascinating to some, it is one
which pre-eminently opens the gates of speculation. That species
have certain geographical and bathymetrical limits in their distribution, may be
an admissible fact in very many cases, but when the reason for this limitation is
sought we are reminded how little we know of natural causes. That certain tracts
of coast have their own peculiar inhabitants, and that the molluscs of the eastern
shores of America, for example, differ from those of the west we must admit ; but
how this has come about, is matter of conjecture. We say that differences of
environment, of food and temperature, are sufficient reasons to account for such
things. On the contrary, we are met with the fact that certain species in a given
genus have a much wider range than others, and we are fain to ask how this is
brought about. The range of terrestrial molluscs is much more restricted than
that of most marine forms. This is readily understood, as the means of dispersal
are very different. The early stages of marine molluscs, if not free-swimming
creatures, are liable to be carried great distances by ocean currents, or the action of
the tides and wind. On the contrary, land-molluscs are creatures of slow progres-
sion, and are liable to have their distribution hindered, either by rivers, mountains,
or seas. Consequently we find that island faunas, as regards the terrestrial species,

326 MOLLUSCS.

are mostly peculiar. It should "be noticed that there are great differences in the
molluscan land-fauna of different areas ; that of North America being, for instance
quite distinct from that of Central and South America.

It is a well-known fact that certain marine gastropods and bivalves inhabit
particular parts of the sea-bottom. Some groups which occur between tide-marks,
such as periwinkles and limpets, are termed littoral forms ; others occurring below
low-water mark, to about ten or twelve fathoms, are said to inhabit the laminarian
zone, or the region where seaweed abounds. Below this, to about fifty fathoms,
extends the coralline zone, so called from the abundance of corallines at this depth,
which also furnishes a lurking-place for certain special forms. Beyond this is the
deep-sea or abyssal region, of which certain species and genera are more or less
characteristic.

Other races, such as the squids among the cephalopods, the various forms of

pteropods and heteropocls, and a few other gastropods, pass their lives far out at

sea upon the surface of the ocean, and are termed pelagic species.

The Mollusca constitute one of the principal divisions (a sub-
Classification. . . . .....

kingdom) of the animal kingdom, and it is subdivided into five

principal sections or classes, namely, Cephalopoda, Gastropoda, Amphineura,

Scaphopoda, and Pelecypoda. These divisions are founded on peculiarities in the

general conformation of the animals, but it is also worthy of notice that the shells

of the different classes differ widely in type. An important feature characteristic

of the three first of these classes is a structure termed the radula. It is situated

within the mouth, and is a kind of muscular tongue armed with teeth, and used in

obtaining or comminuting food. The armature of this radula, odontophore, or

lingual ribbon, is subject to great variation, and these differences have afforded

characters for distinguishing various groups among the gastropods. There are a

few genera of Gastropoda which are peculiar on account of the want of this

masticatory organ, and it is also unknown among the headless bivalves.

The Squids, Cuttle-Fishes, and Nautili, — Class Cephalopoda.

The cephalopods are considered the most highly organised of all molluscs, and
some of the species are remarkable for the enormous size they sometimes attain.
They are exclusively marine animals, leading a predatory life out on the high
seas, or among rocks in shallow water, or about low-water mark. The sexes are
distinct. They may be recognised by the symmetry of their general conformation,
the fleshy arms or tentacles situated around their mouths and in front of the
head, and by their retrograde mode of progression, which is effected by the
expulsion of water from a particular organ, termed the siphuncle or funnel. With
one exception — the nautilus — none of the living cephalopods possess an external
shell, and they are consequently termed naked molluscs. Nearly all decapods,
that is, those species which are provided with ten so-called arms — have a straight
calcareous or horny internal shell, which is a strengthening support to the back.
Spirula, however, although a decapod, is an exception, and possesses a segmented
shell, coiled up like a ram's horn, and concealed within the hinder part of the
animal's body. The external shell wherein the female argonaut dwells is not the

CEPHALOPODS. 327

equivalent of the shell of the nautilus, or of the gastropods. It is not attached
to the animal by any special muscle, but held to the body by two of the arms,
especially developed for this purpose. It is, in fact, merely a receptacle for the
ova, but at the same 'time affords protection to the argonaut herself. All the rest
of the octopods are without shells of any description.

The body of a cephalopod consists of a muscular sac, in the cavity of which
the viscera are placed. In front of the body projects the head, which, in one of
the two main sections into which the class has been divided — namely, the
Dibranchiata, or those provided with only one pair of gills — is crowned with eight
or ten fleshy muscular arms, in the midst of which the mouth is situated. This is
armed with two strong jaws, in shape very similar
to the beak of a parrot. They are curved,
pointed, and of a horny substance in the two-
gilled cephalopods, and somewhat calcareous in
the four-gilled group. Within the mouth is the
rasping tongue, covered with the sharp siliceous

. - .", . , -. . , UPPER (a) AND LOWER (b) PORTIONS OP THE

hook-like cusps or teeth, arranged in regular BEAK 0P A CUTTLE.FISH (Sepia).

transverse series, one behind the other. The

eyes, two in number, are placed on each side of the head, and are of enormous size
in some of the decapods. On the ventral side the muscular sac is disconnected with
the head, leaving a more or less wide opening admitting the water to the gills. The
water is then expelled through the so-called funnel with more or less force, according
to the requirements of the animal. If it be at rest, the expulsion of water is carried
on very quietly, but, on the contrary, with much greater force if the animal is in
motion. Besides water, other secretions from the body are extruded through the
funnel, and especially a dark fluid secreted in a special ink-pouch. When disturbed
or irritated, this ink is discharged by all cephalopods, excepting the nautilus, and is
supposed to be a means of defence. Mixing with and clouding the surrounding
water, we can well suppose that the attack of a pursuing fish might be checked, and
the squid or cuttle effect its escape in the darkened fluid. The arms, or feet, of the
octopods and decapods are more or less elongate and capable of movement in any
direction, and are furnished on one side with numerous suckers, by means of which
the animal holds on to anything that it may seize with such tenacity that the suckers
themselves are liable to be torn away rather than loose their hold. They are often
furnished at the edge with a toothed horny or calcareous ring, and connected with
the arms by slender stalks. Cephalopods employ their arms in walking and
climbing, and, owing to their position, have to progress head downwards when
creeping on the sea-bottom. They are connected at the base by a skin, in some
species extending some distance up the arms, and forming a sort of umbrella, which
is doubtless of use in the capture of their prey. In the nautilus the arms are
different, being short, pointed tentacles, unprovided with suckers.

The nervous system is more developed than that of other molluscs ; it is con-
centrated around the gullet, and protected by a cartilaginous plate, a sort of rudi-
mentary skull. The skin of the naked cephalopods is more or less thickly studded
with points or dots of various colours. These pigment-cells are subject to alter their
tint at the will of the animal, which, chameleon-like, assumes very different aspects

328 MOLLUSCS.

Some species also, which, when in repose or undisturbed, have the outer skin
smooth, if irritated, become suddenly covered with conical tubercles or more or less
elongate cirri.

Cephalopods are very voracious, feeding on fishes, molluscs, and crustaceans.
Some species pursue and capture their prey, while others lie in wait and pounce
upon it suddenly. Like every other group of animals, they have their enemies,
being devoured in enormous quantities by cetaceans, fishes, and sea-birds. In
some countries various species are esteemed as an article of food. Although about
four hundred and thirty, species of living cephalopods have been described, some of
these are so inadequately defined, that the total, in round numbers, does not prob-
ably exceed about three hundred and eighty. These have been arranged in some
seventy-five genera and fourteen families. About half the genera contain but a
single species each, while nearly half the known forms belong to the three genera
Octopus, Sepia, and Loligo. The cephalopods of bygone ages far surpass in number
those which survive, and it is probable that we only know but a moderate
proportion of the forms that have passed away in the various geological epochs ;
for what idea have we of the shell-less tribes which may have inhabited ancient
seas, whose soft bodies have decomposed at death, leaving not a vestige behind ?
It is only those with internal or external shells which have been preserved ; and
what proportion of all the forms that have existed in all times do the fossilised
remains known to us represent ? The seas of our* own times contain a large
number of cephalopods, the existence of which in past geological ages cannot be
proved ; but, on the other hand, we know of great numbers of fossil genera and
species of which there are no living representatives. The entire order of the
Ammonoidea, which contains the well-known discoid, convoluted, chambered
Ammonites, is entirely extinct, and it is a matter of uncertainty whether
they should be classed with the dibranchiate or tetrabranchiate group, or be
regarded as a distinct order by themselves. On the contrary, although the
probability is that many existed in bygone ages, only a few fossilised remains of
octopods have been identified with certainty, and the Spirilla of to-day, which
occurs in countless thousands, also appears to be unknown in the past.

Two-Gilled Group, — Order Dibranchiata.
Octopus Tribe, Suborder Octopoda, — Family OctopodiDjE.
Commencing with the order Dibranchiata, we find this divided into the two
suborders, Octopoda and Decapoda, according to the number of arms. Of these
the octopods comprise several families distinguished by differences in the general
build, the presence or absence of lateral fins, the number of rows of suckers on
the arms, variations in the radula, etc. Since the establishment of public aquaria,
in comparatively recent years, most persons have had an opportunity of seeing
the unsightly octopus in its native element. An unpleasant, forbidding creature
it is, contracting and swelling, or looking like a shapeless but living mass. We
observe the eight tapering arms, with the two rows of suckers along the inner
side of each, numbering about two thousand altogether in some individuals. We
note the two staring eyes which seem ever on the watch, the funnel often exposed
to view, and the mottled skin. About ninety species of octopus are known, which

CEPHALOPODS.

329

occur in all seas. Variations in colour, the relative length of the arms, the size
of the suckers, and the character of the hectocotylised or modified arm of the male,
are among the distinguishing features of the species. Although we usually speak
of the octopods as shell-less or naked molluscs, an indication of an internal shell
is present, in the form of two short styles, embedded in the tissues of the mantle.
These molluscs are solitary creatures when adult, but they are said to herd together

COMMON OCTOPUS.

in small companies when young. They live in the fissures of rocks, or hide away
beneath great boulders. When they walk or creep, they elevate the sack-like
body above the head, and progress slowly upon the extremities of the arms, which
are a little curved near the tip. They can creep in any direction, but they prefer
a side-way movement. On the contrary, if their progress in walking is com-
paratively slow, this is compensated by the rapidity of their movements when
swimming. Body foremost, with the arms stretched beyond the head, they dart

33Q MOLLUSCS.

backward with great rapidity, being propelled by the successive expulsions of
water through the funnel. The arms are also made use of in swimming, and
those which are provided with an extensive connecting web are the most effective
swimmers. None of the octopods ever attain such enormous dimensions as some
of the decopods, still some would be very dangerous foes to cope with beneath the
water. Mr. J. K. Lord saw the arm of an octopus, captured at Vancouver Island,
which measured 5 feet in length, and was as thick as his wrist ; and M. Verany
has given an account of a specimen which measured 3 metres from tip to tip of
the outstretched arms. In the account of the molluscs, obtained during the voyage
of the Saniarang, Mr. Adams observes : " Octopi of enormous size are occasionally
met with among the islands of the Mei'a-co-shima group. I measured one, which
two men were bearing on their shoulders across a pole, and found each arm
rather more than 2 feet long, giving the creature the power of exploring an area
of about twelve feet without moving, taking the mouth for a central point, and
the extremities of the arms to describe the circumference."

In 1872 a very large specimen was stranded on the beach in the Bahamas, the
arms of which were 5 feet long, and the weight was estimated at 200 to 300 lbs.
The eggs of the Octopus vulgaris when first laid are small, oval, translucent
granules, resembling grains of rice, not quite the eighth of an inch long. They
are fixed along and around a common stalk, to which every egg is separately
attached. These clusters vary in length according to the condition or age of the
parent ; those produced by a young octopus seldom exceeding three inches in
length, and from twelve to twenty in number ; but a large, full-grown female
will deposit from forty to fifty of such clusters, each about five inches in length.
In each of these clusters Mr. Lee counted about a thousand ova, so that a
single octopus may produce at one laying a progeny of from forty to fifty
thousand. The mother octopus watches, tends, and guards the egg-clusters for
about fifty days, when the young emerge from the capsules. The sexes differ
scarcely at all externally, but at the breeding-season a curious modification in the
third right arm of the male is noticeable. It becomes swollen, and from it a long
worm-like process is developed, furnished with two rows of sockets (the Hecto-
cotylus). From the end of this process extends a slender, elongated filament.
When its owner offers his hand to a female octopus, she not only accepts it, but
keeps it, for this remarkable outgrowth is then detached from the arm of her
suitor, and becomes a moving creature, having separate life, and continuing to exist
for some time after being transferred to her keeping. The lost portion of the
hectocotylised arm of the male is gradually reproduced, and in due time assumes
its former appearance.

A second group of octopods (Eledone), which occurs in the Mediterranean and
also on the British coasts, differs from the common octopus in having but a single
row of suckers down each arm. In E. moschatus, the body is very changeable in
form, pouch-like, oval, rounded, or pointed behind, smooth or warty, just as the
animal likes. The great size of the mantle-opening, which extends a little over the
back, is also remarkable. It is of a grey, yellow, or yellow-brown colour, with blackish
spots, and a bluish edge to the web, and is met with on sandy and gravelly bottoms
at all times of the year, more rarely among rocks. The rapidity with which the

CEPHALOPODS.

331

creature changes its colour is amazing. At the slightest disturbance a dark
shade passes with the rapidity of lightning over the whole body. When it seizes
its prey its entire skin becomes yellowish, studded with blackish symmetrical spots,
and covered all over with conical tubercles. These molluscs have a strong musky
smell, but in spite of this they are not unfrequently seen in the Italian markets,
and purchased by the poorer classes.

Other octopods are Cirroteuthis, Pinnoctopus, Tremoctopus,
' Amphitretus, and a few other allied genera, and Argonauta, several
of which represent families by themselves. In Cirroteuthis the arms are con-
nected throughout their entire length with a thin membrane, forming a sort of
umbrella, at the bottom of which is the mouth. They are furnished with only a
single row of suckers down the middle, but have a series of short cirri on each
side, and the body is provided with two lateral fins. Seven species of this genus
are known at present. C. maura was captured at a depth of thirteen hundred and
seventy -five fathoms, and C. pacifica, off New Guinea, in two thousand four
hundred and forty fathoms. C. muelleri, the type of the genus, occurs on the coast
of Greenland. Pinnoctopus is remarkable for a fin-like expansion, extending the
whole length of the body and uniting behind. In P. cordiformis — the only known
species, and an inhabitant of the shores of New Zealand — the arms are long, and
united at the base by a somewhat large membrane. Tremoctopus has no lateral
expansions or fins to the body. The female has the two dorsal pairs of arms
united by membrane, the two other pairs free ; the male is without the interbrachial
web ; the head is large, having two pores on the upper and under sides. Nine
species altogether have been described from the Mediterranean, North Atlantic, and
Pacific. The genus Amphitretus is one of the remarkable forms obtained during the
Challenger expedition. It possesses the character, unique among cephalopods, of
having the mantle fused with the siphon in the median line, so that there are two
openings into the branchial cavity, one on either side, whence the name.

Family ARGONATJTIDJE.

The argonaut, or paper-nautilus, is one of the most interesting of the octopods,
for around it for many years there hung a mystery and uncertainty. Some con-
cluded that the shell was formed by another mollusc, and was merely taken
possession of by the cephalopod, as a convenient abode or boat to swim in, or
rather to sail in, for it was stated to raise aloft its two expanded arms to catch the
breeze, and thus to voyage onward. This, for many years, has been proved to be
mere fiction. The shell, with which only the female is provided, is of her own
manufacture, and she swims just the same as other cephalopods. It is large, not
adhering to the body of the animal, but retained in position by the application on
the outside of the dorsal pair of arms, which are dilated and especially adapted for
the purpose. Whether the argonaut ever quits its shell voluntarily or only
by accident is unknown ; specimens have been captured at sea without any shell,
and they have lived for some time in that condition. A specimen was placed in an
aquarium at a time it was out of its shell. This it re-entered, and remained in it
the whole period, about fifteen days, it was in captivity. It invariably swam at the

332

MOLLUSCS.

SHELL OF FEMALE ARGONAUT.

surface of the water with the coiled part of the shell upwards, a small portion being
above the surface, to which the aperture was at right angles or inclined at an angle
of 45°. It appeared calm and not subject to agitation like the octopus. It

remained perfectly immovable, for no menace or
excitement appeared to affect this appearance
of tranquillity. Like the octopus, it exhibited
chameleon -like changes of the skin, but not so
rapidly or with such intensity as that animal.
During all the time the specimen lived, all the
arms, which have two rows of suckers, were
kept within the shell, except the expanded
posterior median pair. These, however, were
also sometimes drawn within. Four of the
arms were bent upwards, four downwards,
leaving the mouth with its parrot-like beak
exposed in the middle of their bases. Between
the lower or ventral pair of arms the funnel was
protruded, by means of which it propelled
itself backwards. This specimen was not seen
either to walk or swim with its arms; but
other observers state that the creature walks
or crawls along the bottom like a gastropod,
by means of the non-expanded arms, carrying the shell above its body. The eye
is round, bordered with black, and the circular pupil is also black.

The shell is supposed to be secreted chiefly by the palmate arms, aided by the
mantle investing the body. It is developed some time after the birth of the argonaut,
and a female has never been seen with a shell before it had attained about an
inch in length. The male argonaut is very different to the female, and much
smaller, being only about an inch in length. It resembles an ordinary octopus in
having neither palmate arms nor shell. The arms are tapering and alike, excepting
the third on the left side, which is specialised. This at certain times, having
passed through various stages of development, is cast off, and attaches itself to the
female, living a free and independent life for a considerable period. The eggs are
small, numerous, and connected together by a network of filaments. They are
deposited far within the shell towards the convoluted portion, and are practically
in contact with the posterior part of the body of the parent. The shell therefore
serves, not only as a retreat for the argonaut herself, but also as a nest for the eggs,
and possibly as a nursery for the young. Very little is known with regard to the
food of the argonaut. As its habits are very similar to those of the octopus, it
seems probable that it may feed upon molluscs and crustaceans, which it might
capture when crawling at the bottom of the sea. A captive specimen was fed with
small live fish, which it ate with avidity. About eight species are recognised,
which have a world-wide distribution, occurring in all tropical and warm latitudes.
The shells of the different species are all of a white colour, and exhibit two distinct
types of surface ornamentation, the one consisting of simple, smooth, radiating
wavy ribs, the other in which these ribs are more or less broken up into nodules or

CEPHALOPODS.

333

tubercles. Argonauta hians is the typical species of the former group, and A.
navicula and A. tuberculata represent the latter.

A, male argonaut (twice nat. size), WITH hkctocotylus enclosed in the sack ; B, MALE argonaut, with

HECTOCOTYLUS FURTHER DEVELOPED.

Suborder Decapoda.

The Decapods form the second division of the two-gilled order, and differ from
the Octopods, as the name implies, by the possession of ten, instead of eight, arms.
The two additional arms differ from the rest in their greater length, and in having
suckers only at the extremity. They are frequently completely retractile within
pouches, and are used as prehensile organs in the capture of their prey. All
decapods are provided with an internal shell. That of the living species is either
horny — the so-called pen (gladius) ; or else calcareous — the bone (sepion) of the
cuttle-fish. In Spirula the shell takes the form of a tube, beautifully coiled, and
divided off into numerous air-chambers by a series of septa or partitions. The arms
of the decapods are furnished with pedunculated suckers, armed with horny rings
or hooks. The head is invariably distinct from the body. The eyes are free and
movable, and either covered with a fixed, transparent lid or skin, or unprotected
and in immediate contact with the water. All the species have either lateral or
posterior fins, and the funnel is provided with an internal valve. They live for
the most part out at sea, but some — Sepia, for example — are met with nearer the
shore. The pelagic forms are often found in immense shoals, and are eaten in
enormous quantities by many cetaceans and large fishes. When pursued by their
enemies, squids have been known to dart out of the sea with such force as to fall
upon the deck of a passing vessel. Decapods may be classified in three sections,
according to the character of the shell, of which the different types have already
been mentioned.

334

MOLLUSCS.

Squids, — Family Loliginid^e.

Some of the commonest of the horny pen-bearing decapods are the true squids
or calamaries (Loligo), which have a more or less elongate body, with very large
lateral fins at the posterior end. The eight sessile arms are provided with two
rows of suckers with toothed horny rings, and the two tentacular arms are long,
slender, and terminate in an expanded club, bearing four rows of suckers. The
pen is large, horny, as long as the body of the animal, and placed beneath the
skin of the back. It is not in any way attached, so that if the skin be slit
open, the shell can be drawn out entire. The common squid (Loligo vulgaris) is
met with all round the British coasts, and occurs in shoals of greater or less extent
in the Mediterranean and Atlantic. The spawn consists of numerous, long, semi-
transparent, gelatinous sheaths, radiating from a common centre. Each sheath is
about 4 inches in length, and contains numerous ova, and it has been computed
that in a single mass of sheaths the deposit of one female contained as many as
forty-two thousand perfect young squids. Mr. Lee observes that he has never
seen these "sea-mops" attached to anything; and the pelagic habits of the calamaries
render it probable that they are left floating on the surface of the sea. They are
deposited in May or June. The calamaries are active animals, and always in
motion. A second genus of squids (Ommatostrephes), frequently regarded as repre-
senting a distinct family, differs from Loligo in having the body very long, the
posterior fins comparatively short, and the pen very narrow. They are gregarious,
and frequent the open seas in all latitudes, and are extensively used as bait in the
cod-fishery off Newfoundland, and also constitute the principal food of dolphins and
the sperm-whale. They are also largely eaten by the albatross and other marine
birds. By sailors they are called " sea-arrows " and " flying-squids," on account of
the rapidity of their movements and their habit of leaping out of the water. It is
said that they frequent the shore in pursuit of the fry of pilchards and other fishes.

The largest of all the Cephalopoda belong to the genus Architeuthis, which
in general conformation considerably resembles Ommatostrephes. Many stories of
gigantic cuttle-fishes appear in the works of old writers, and although, in the main,
great exaggerations, they are to some extent founded on fact. We are, perhaps,
too sceptical to believe in an octopus rising from the sea, and carrying off* a three-
masted ship. Yet some of the squids are of such enormous size, that we can
imagine they constituted the source from which these old tales were derived. In
November 1874 a specimen was brought ashore at St. John's, Newfoundland, by
some fishermen, who captured it in their herring-nets. It was more or less
mutilated in the capture, but the following measurements were taken from the
parts preserved. Body 7 feet long, tail-fin 22 inches broad, tentacular arms 24 feet
in length, short or sessile arms 6 feet long, some of them being as 10 inches round
at the base. Particulars of several other specimens of gigantic squids, varying
in total length from 30 to 52 feet, and also taken near Newfoundland, have been
recorded ; the estimated weight of one of these being 1000 lbs.

On the 24th of April 1875 a large calamary was met with off' Boffin Island,
on the Irish coast. The crew of a " currah " observed to seaward a large floating
mass. They pulled out to it, believing it to be a wreck, but found it was an

CEPHALOPODS.

335

enormous cuttle-fish, lying perfectly still, as if basking on the surface of the water.
Paddling up, they lopped off one of its arms. The animal immediately set out to

COMMON SQUID, WITH PEN ON THE LEFT (nat. Size).

sea, rushing through the water at a tremendous pace. The men gave chase, and,
after a hard pull, came up with it, five miles out in the Atlantic, and severed

33^

MOLLUSCS.

another of its arms and the head. The shorter arms measured each 8 feet in
length, and 15 inches round the base ; the tentacular arms are said to have been
30 feet long. A single arm of a large squid, supposed to have been found off the
coast of South America, is 9 feet long and 11 inches round the base, and has two
rows of suckers, with toothed, horny rings, each row consisting of one hundred
and fifty suckers. The largest of these rings is half an inch in diameter, whereas
the smallest, near the tapering end of the arm, is only about the size of a pin's
head. Judging by other specimens, it is probable that this creature must have had
a body 10 or 12 feet in length, with tentacles over 30 feet long.

Some portions of a remarkable gigantic cephalopod were obtained by the
Prince of Monaco off the Azores, which were vomited by a harpooned sperm-whale
in its death-struggle. The body of this huge squid was covered with scales arranged
spirally like those of a pine-cone ; and from this character — unique among the
Cephalopods — it has been placed in a separate genus Lepidoteuthis.

Family SEPIOLID^:.

Sepiola is represented by a small decapod not unf requently found on the British
coasts. Mr. Lee observes that " it has the faculty of rapidly changing colour, and,

UPPER AND LOWER VIEWS OF SEPIOLA.

if angered or alarmed, its hue is almost instantaneously altered, from a pale parch-
ment dotted with pink to a deep reddish brown. In its habits this little animal

CEPHALOPODS. 337

differs as much from the Sepia as the latter from the octopus. It naturally buries
itself up to its eyes in the sand ; but as sand is apt to harbour impurities, which in
a bowl or tank become corrupt, and generate poisonous sulphuretted hydrogen,
the bottom of these receptacles is usually covered with shingle. It is most
interesting to notice how, in obeying its burrowing propensity, the Sepiola adapts
itself to its circumstances and entirely deviates from its customary mode of
procedure. To make a sand-pit for its hiding-place, it will direct upon it strong
jets of water from its funnel, and thus blow out a cavity in which to seat itself,
and allow the disturbed particles to settle over and around it ; but, as the pebbles
are too heavy to be thus displaced by its blasting apparatus, it removes them, one
at a time, by means of its arms, which are large and strong in proportion to its
little short body." This same species, S. rondeletii, is common throughout the
Mediterranean, and is sold in the fish markets of Italy.

Families ONYCnOTEUTHIDJE and CHIROTEUTIIIDuE.

The squids belonging to the genus Onychoteuthis are very similar to Loligo,
but are distinguished by having the club of the tentacular arms furnished with
strong horny hooks. They are mostly of small size, only a few inches in length ;
but a very large species (0. robusta) was observed off* the coast of North- West
America, and measured 8 feet in length from the base of the arms to the posterior
end of the body. It has since been placed in the allied genus Ancistroteuihis. One
of the most remarkable of the decapods is the genus Ghiroteuthis, easily recognis-
able by the enormous length of the tentacular arms, which are many times the
length of the body, so that the animal is enabled to capture its prey at some
distance. C. veranyi occurs in the Mediterranean, C. bonplandi in the Atlantic,
and C. lacertosa off the east coast of the United States.

True Cuttle-Fishes, — Family Sepiibm.

In the cuttle-fishes of the genus Sepia the body is oval with a fin on each
side extending the whole length. The eight sessile arms are furnished with
suckers having foot-stalks, and the long tentacular arms are entirely retractile
within the head. The dorsal plate, shell, or cuttle-bone, is generally almost as wide
as the body, and placed beneath the skin of the back, with the terminal spine
posteriorly. This is supposed to protect the hinder parts of the animals, in the
frequent collisions they are exposed to in swimming backwards. About sixty
species of Sepia have already been described, none of very large size, the largest
bone being only about a foot and a half in length. A fine specimen of S. apama
in the British Museum is 17 inches long. They occur in all parts of the world, and
three species are recorded from the coasts of Britain. They live near shore, and
feed upon fish and crustaceans, which they seize with their rapidly unrolled
tentacles. Speaking of the common cuttle-fish (S. officinalis), Mr. Lee observes
that though flabby and clammy in death, it is a lovely object when alive. Unlike
the octopus, but equally rapacious, it loves the daylight and freedom of the open sea.
Like the calamaries, the sepia is extensively employed as an article of diet in many

VOL. VI. — 22

338 MOLLUSCS.

parts of the world. Dried cuttle-fishes are exposed for sale in the bazaars or
markets throughout India, and may be seen among the articles of Chinese,
Japanese, and Siamese food. The ink of the cuttle-fish was employed as a writing
material in very ancient times, its use being mentioned in the works of some of the
old Latin writers; the ink-bags of cuttles are still manufactured into sepia by
artists' colourmen. Eggs of the common cuttle resemble black pointed grapes, each
having a flexible stalk, looking and feeling like indiarubber. They are generally
attached to the stems of seaweed. Each capsule contains a single young one.

Family Spirulid^:.

Spirula represents the last of the three divisions into which the living
decapods have been divided. The shell of the spirula is abundant on the shores
of some tropical countries, but the animal is scarcely ever met with. Only a few
specimens have been captured, and most of these are in bad con-
dition. The shell is entirely white, pearly within, placed verti-
cally within the posterior part of the body, so that the spire
corresponds to the ventral side of the animal. It is a loosely
coiled structure, resembling a ram's horn, and is divided into a
Spirula permi. number of chambers by fine concave partitions, like the shell of
nautilus, each one pierced by a slender tube or siphon near the
inner curve of the shell. Three species are known, distinguished by differences
in the soft-parts, the shells being similar. ■

To the same group as the Spirula belongs the extinct family of
Belemnites. . . , . f . . ,

Belemnitidce, ranging from the Lias to the Chalk, and whose skeletons

are commonly known as thunderbolts. They possess a tapering chambered shell,

inserted into the summit of a long spear-like guard. Most of the species belong to

the typical genus Belemnites.

Four-Gilled Group, — Order Tetrabranchiata.
Family Nautilid^e.

The nautilus is the sole living representative of this order, and although not
so rare as the spirula, the animal of the nautilus is by no means common in
collections. It is probably an inhabitant of deepish water, and only likely to be
obtained alive by dredging, although a few specimens have been occasionally cap-
tured at the surface. The animal is contained within the last compartment (A) of a
chambered shell, within which it is completely retractile. It does not resemble any
of the dibranchiate cephalopods, having numerous small retractile feelers or tentacles,
without any suckers, in place of the eight or ten sucker-bearing arms of that order.
The beaks are very solid and calcareous, not entirely horny as in the dibranchiates.
The eyes are small, and raised on short stalks ; the funnel is not a complete tube,
being formed of two lobes which fold over one another, but are not joined together.
To the posterior end of the body is attached a slender fleshy cord, termed the
siphuncle (a), which passes through holes in the septa of the shell up the coiled spire.
It is enclosed in a horny tube, which is again coated with a calcareous deposit.

CEPHALOPODS.

339

SECTION OP SHELL OF TEARLT NAUTILUS

(much reduced).

The function of the siphuncle probably is to preserve the vitality of the first formed
portion of the shell, which without some such means of preservation would be
liable to decay. The animal is somewhat feebly attached to the shell by two large
adductor muscles one on each side of the body, which are, as it were, connected by
a muscular girdle of the mantle passing round the body from muscle to muscle.
The chambered shell is beautifully pearly within, but has an external porcellaneous
coating. A full-grown shell has about thirty -six septa, which are relatively
equidistant, showing that the growth of the animal is regular and gradual
throughout life. The septa give immense strength to the shell, sufficient to
resist the pressure of the water at great
depths upon the air-chambers between them.
These air-chambers undoubtedly serve to
buoy up the shell when the animal is swim-
ming or desires to rise to the surface ; but
the old stories of its filling the cells at
pleasure with either air or water, and so
rising to the surface or descending to the
bottom, are mere fables, and comparable to
the legends respecting the sailing of the
argonaut. The shells of the male and
female are said to present certain slight
differences. Very little is known of the
habits and economy of the pearly nautilus,
but, as already remarked, it is most likely a deep-water animal, as a rule living
at depths far beyond the action of storms. It would probably be obtained by
dredging or by means of baited traps. A specimen dredged off the Fiji Islands, at
a depth of about three hundred and twenty fathoms, was kept alive for some
time in a tub of sea water. The mode of growth of the nautilus has been a
subject of much discussion, and the way in which the successive air-chambers and
septa are formed is not known with certainty. The living forms of Nautilus
probably belong to three distinct species. N pompilius has a wide distribution
in eastern seas, specimens having been obtained in the Indian Ocean (Andaman
Islands), at the Moluccas and Java, and in the Pacific at the New Hebrides and
Fiji ; N. umbilicatus is recorded from the Solomon Islands, and New Ireland ;
and N. macromphalus from New Caledonia and the Isle of Pines. The animal of
Nautilus is used as an article of food among the natives of the New Hebrides,
New Caledonia, and Fiji, it being captured by the Fijians in traps baited with
boiled crayfish.

The genus Nautilus is of great antiquity, dating from an early
epoch in the Palaeozoic period, and forms the type of the family
Nautilidw, which includes several extinct genera. There are allied extinct
families, collectively forming a group characterised by the simple structure of the
septa of the shell, such septa having their concavities directed towards its aperture.
Among these, the Orthoceratidw, as typified by the Palaeozoic genus Orthoceras,
may be characterised as unrolled nautili, the shell — which sometimes reaches an
immense length — forming a long cone.

Allied Families.

34°

MOLLUSCS.

a ceratite [Ceratites nodosus).

AN AMMONITE

(Cardioceras cor datum).

Another well-marked group is that of the Ammonoidea, represented by the
goniatites of the Palaeozoic, and the various types of ammonites of the Secondary

rocks, as well as by

the turrilites of the

Chalk. In all these

the edges of the

sutures, where they

join the shell, are more

or less complexly

angulated or frilled,

the complexity being

very great in the

ammonites, but a

simpler type obtaining

in the goniatites.
Whereas in the two latter the shell is coiled in a flat spiral, in the turrilites it
forms a cone, while in the hamites and baculites of the Chalk it is either straight
or partially coiled. In the ceratites and ammonites (which include Ceratites,
Cardioceras, and many other genera) the mouth of the body-chamber of the shell
was closed by an operculum, which often consists of two pieces meeting in the
middle line, and the whole being heart-shaped. In other forms the operculum
was single. Mr. Cooke observes that " some authorities hold that the members of
this suborder belong to the Dibranchiata, on the ground that the protoconch
resembles that of Spirula rather than that of the Nautiloidea. Others again
regard the Ammonoidea as a third and distinct order of Cephalopoda. Their
distribution extends from the Silurian to (possibly) the early Tertiary. No trace
has ever been found of an ink-sac, mandible, or hooks on the arms ; and the shell
was undoubtedly external."

EDGAR A. SMITH.

CHAPTER X.

Molluscs, — continued.

The Gastropods, — Class Gastropoda.

The Gastropods constitute by far the largest division of the Mollusca, and include
among their number forms which bear no external resemblance whatever to one
another. Some are free-swimming animals, living far from land, out on the open
seas ; others occur in shallow water, or between tide-marks ; while others are
dwellers on the land, or frequent rivers and lakes. Some have internal, others
external shells, whilst many have no testaceous structure of any description.
Snails, whelks, and periwinkles are typical forms of Gastropods, and the more
aberrant types are represented by the Nucleobranchs, Heteropods, and Pteropods.
The typical Gastropods are all crawlers, moving like a slug or snail by a continual
expansion and contraction of the muscular foot. Some breathe bj7- means of gills,
others by a lung, while certain forms are provided with both modes of respiration.
They are generally furnished with a spiral shell when adult. They are mostly
unsymmetrical animals, lying spirally coiled within the shell ; this want of symmetry
being particularly manifested in the breathing-organ. In many marine forms there
is only a single gill, but in a few genera — Fissurella for example — the gills are
paired. There is always a more or less distinct head, bearing one or two pairs of
tentacles, and there are generally a pair of eyes situated at the base or end of the
tentacles; or raised upon short stalks. The mouth is usually provided with one or
more jaws, and the lingual ribbon, or radula, within the mouth, varies greatly
in its armature, and plays an important part in the various schemes of classification
which have been proposed. While enormously developed in some groups, such as
the limpets, in a few it is entirely wanting. It consists of a thin chitinous mem-
brane, the surface of which is beset with a multitude of so - called teeth,
symmetrically arranged in transverse or oblique series. The teeth are siliceous,
insoluble in acid, and capable of rasping away hard substances. With it the whelk
and other carnivorous forms bore through the shells of bivalves, and the limpet
eats away the calcareous nullipore. Not only is the form of the teeth extremely
variable, but their number varies enormously in different groups. In an Eolis, one
of the Nudibranchs, there are but sixteen teeth ; in a Doris, belonging to the same
group, there are as many as six thousand, whilst in a large species of Helix the
number has been estimated at nearly forty thousand. The shells of Gastropods
are usually spirally coiled as in the snail, but sometimes they are tubular or conical,
like that of the limpet. The forms of spiral shells are innumerable and very
unlike ; some being globose, with simple rounded aperture, while others are narrow
and long, with prolonged spires, and the mouth produced into a long anterior beak.

342 MOLLUSCS.

The colour and ornamentation of the surface are also as varied as the shape.
Nearly all spiral shells are dextral, but a few genera {Physa and Lanistes) are
normally sinistral ; while in other groups (Achatinella, Amphidromus, etc.) some of
the species are indifferently dextral or sinistral. A large proportion of the Gastro-
pods entirely or partly close the aperture of their shells with what is termed an
operculum. This is sometimes horny, like that of the common periwinkle, or it may
be solid and calcareous as in the Turbinidce. The different forms assumed by this
structure have afforded characters for separating many groups generically. The
operculum is generally attached to the hinder part of the foot, so that when the
animal withdraws within the shell — it more or less closes the aperture, and thus
protects itself. In many species the operculum is very small, and would not serve
as a defensive weapon, whilst in others it is altogether wanting. Gastropods may
be classified in three principal divisions or orders, namely, the Pulmonata,
Opisthobranchia, and Prosobranchia.

The Lung-Breathing Group, — Order Pulmonata.

The order Pulmonata comprises all the true land-snails, — excepting such as are
provided with an operculum, — the inoperculated forms of fresh-water snails, and the
family of the Auriculidce. The latter forms a considerable group, the members of
which are chiefly met with in salt or brackish marshes, although there. are three or
four genera which are strictly littoral in their habits. All the Pulmonata are pro-
vided with a breathing-cavity, which is not freely open as in the terrestrial and
fresh-water Prosobranchs, but has only a small opening which is contractile so as
to exclude the water in the aquatic species, and the hot air during the heat of
summer in the terrestrial forms. This lung-opening is seen on the right side of
most snails and slugs a little behind the head, and at once closes up if the animal
be molested. With a few exceptions, the fresh-water Pulmonates rise to the surface
to breathe, and are suffocated if prevented from obtaining the requisite supply of
air. They can be drowned just as easily as a slug or snail beneath the water, but
naturally the process would be longer in these animals, in which the breathing is
habitually much slower. In the case of Ancylus, however, this could not be
effected ; and a fresh-water pulmonate, Physa lamellata, from Madagascar, possesses
a well-formed gill.

The Pulmonata may be separated into two main divisions, according to the
position of the eyes. In the Stylommatophora, represented by slugs and snails,
these are situated at the tip of retractile tentacles, whereas in the Basommatophora
they are placed at the base of the tentacles, which are only contractile and not
retractile within themselves as in the former section. The Stylommatophora are
mostly more or less slimy, and leave a mucous track behind when crawling.
Although they are chiefly vegetarians, some are not only carnivorous, but even
cannibals at times. They are found in all parts of the globe, from the Arctic
regions to the Tropics, but are most abundant in those countries where there is
plenty of lime and moisture. The sexes are not distinct but united in each
individual. The eggs of terrestrial molluscs are far less numerous than those of
the marine forms, and are deposited separately. They are mostly round or egg-

GASTROPODS.

343

shaped, and are generally laid in the earth under stones or leaves, and there left
to hatch by themselves. On emerging from the egg, the animals are practically the
same as the parent, but the form of the shell, when present, generally alters very
much in the course of growth.

Shelled Slugs, — Family Testacellid^

The shelled slugs, or Testacellidw, have no jaws, but are armed with a tongue
bearing oblique series of long, narrow, pointed teeth, indicative of their carnivorous
habits. While some members of the family are without any external shell, the
majority are provided with shells capable of entirely covering the animals, but a
few have only very small ear-shaped shells attached to the upper surface of the
hinder end of the foot. To the latter group belongs Testacella, the typical form
of the family. This genus includes elongated slug-like animals, with the breathing
orifice at the posterior end of the body, which is capable of great extension and
contraction. They prey upon earthworms, which are pursued in their burrows under
ground. In a recent account of the habits of T. scutulum, Mr. Webb observes that
it usually seized the anterior
end of the worm, and gradu-
ally swallowed it ; but occa-
sionally the middle was
seized, in which case the
worm forced itself away.
During cold northerly and
easterly winds these crea-
tures enclose their bodies in
a kind of cocoon, like that
of the silk-worms, which is
secreted from the skin, and
often mixed with earthy and
extraneous particles. These slugs deposit a few calcareous eggs, which in form
are as symmetrical as those of a bird, and large in proportion to the size of the
animal. It is doubtful whether this genus is truly indigenous to Great Britain,
or merely an introduction of comparatively modern times. The only other parts
of the world besides Europe where Testacella occurs, are Algeria and the Azores,
Madeira, and Canary Islands.

Glandina forms an extensive genus of Testacellidw, chiefly restricted to the
central parts of America ; one species, however, being European. Like Testacella,
these are very voracious, and even attack their own species. Daudebardia is another
slug-like genus of this family, carrying a small shell upon the tail. They occur
in Southern and Eastern Europe and Western Asia, and in New Zealand are closely
represented by Schizoglossa, the external aspect of which is very similar. The
allied Streptaxis is remarkable for the peculiar obliquity of the last or body-whorl
in relation to the spire in most of the species. The first-formed part of the shell
is regular in its growth, like an ordinary garden snail -shell, but suddenly the
growth becomes irregular, giving the shells a very oblique and distorted appearance.
The object of this deviation from the ordinary form of growth is not apparent, but

shell-bearing slug, Testacella haliotidea (nat. size

344

MOLLUSCS.

it doubtless serves some special purpose. Nearly all the species of this genus are
of a whitish colour, polished or obliquely striated. They chiefly occur in South
America, Tropical Africa, Southern Asia, and certain islands in the Indian Ocean.

True Slugs, — Family Limacibjs.

This family contains many genera of naked slugs, and several either partly or
wholly protected by well-developed shells ; the hinder end of the foot in some
forms terminating in a conspicuous mucus or slime-pore. The typical slugs are
mostly elongate animals, capable of great contraction, and always pointed or
attenuated behind. The mantle forms a sort of shield, placed over the fore-part of
the back, and beneath this is situated a small calcareous plate, representing the shell.
These plates occur fossil in Eocene beds. The respiratory orifice is seen on the
right side of the shield, but rather far back. The head is prominent in front,
bearing two pairs of retractile tentacles, of which the upper are the longest, and
furnished with eyes at the bulbous tips. The mouth is provided with a horny
upper jaw, which is smooth, with the cutting edge produced into a sort of beak in
the middle. The radula has numerous transverse series of horizontal or slightly
oblique teeth, of which the central tooth is three-pronged, the laterals about the
same height as the central one, while the marginal teeth are narrow and acute. The
body is united to the foot, and is more or less wrinkled ; the wrinkles being most
conspicuous when the slug is contracted, and to some extent characteristic of the
different species. The Limacidce live in damp places, out of doors, or in cellars,
and hide away during the daytime under stones, dead leaves, or in fact in any place
where it is dark and moist. They feed chiefly on decaying vegetation, but some
are more or less carnivorous. Certain species are great pests in gardens. Limax
agrestis, the " milky slug," — so called from the opaque white colour of its mucus, — .
is a very common species in England ; it is very fond of strawberries, and is also
said to feed upon earthworms. These slugs increase in numbers rapidly, and are
said to produce several families in the course of a summer.; a pair having been
known to lay nearly eight hundred eggs. Some species of Limax are capable of
lowering themselves to the ground from the branch of a tree by secreting a slimy
thread. The largest species occuring in Britain is L. maximus, which has a very
wide range on the Continent, and sometimes exceeds 6 inches in length. One may
often notice numbers of a minute white parasitic mite (Philodromus) running about

the body of this slug, and it is

said also to live in the respira-
tory cavity, but does not appear
to cause any annoyance or
injury to its host.

In the genus Vitrina the
animal is provided with a
fragile, external, horny shell,
not sufficiently large to receive
it entirely, when contracted. The shells are all very much alike, and precisely
similar to those of Helicarion, another genus of Limacidce, which, however, is
distinguished by having the foot truncated obliquely behind, and furnished with

glass-snail {Vitrina) and amber-snail (Succinea). (Nat. size.)

LAND MOLLUSCS.

.

■
••'; no'nK lo usit^haV .'"51 ,M >. ! ,T .9

1, 2. Varieties of Helix hortensis. 5. Limax maximus. 10. Helix pomatia. 18. Cyclostoma clegans.

3. Agriolimax agrestis. 6, 7. Helix nemoralis. 11, 12. Clausilia ventricosa. 14, 15. Varieties of Arion emplricorum.

4. Bulinrinus moutanus. 8, 9. Helix personata.

GASTROPODS

345

a large terminal mucus -pore, and there are other anatomical differences. The
single British species is here figured. Unlike Vitrina, the snails known as Zonites
and Vitrea, together with some allied genera, are wholly retractile within their
shells. There are several British species of Vitrea, and their identification from
the shells alone is a matter of considerable difficulty. In their habits they closely
resemble Vitrina, being carnivorous rather than vegetarian. They greedily devour
any kind of animal food, even in a putrid condition, and are also said to prey
upon some of the larger snails. They are generally found hidden away under
stones, dead leaves, or moss, and some of them emit a strong smell, like garlic, which
is perceivable at a distance of some feet.

The Snail Tribe, — Family Helicibje.

Like the Limacidw, this family includes forms with or without an external
shell. In nearly all the genera the cutting-jaw of the animal is more or less
ridged, and not smooth as in Limax. The principal distinguishing character occurs
in the structure of the radula, which is composed of many rows of very numerous
similar square-based teeth, arranged so regularly as to have a tesselated appearance.
It is very broad, and the number of teeth in a row, although usually less, is some-
times as great or even greater than the number of rows. This family includes an
enormous number of species from all parts of the globe. These occur everywhere
and in all climates ; in dense forests, on the top of grassy downs, in valleys, fields,
lanes, in the arid desert, and at an elevation of some ten thousand feet both in the
Old and New World.

To an ordinary observer, the members of the genus Arion (sometimes placed
in a separate family, Arionidw) are merely slugs. Externally the resemblance is

black slug, Anon empiricorum (nat. size).

very close, but the different position of the respiratory orifice, and the presence of
a mucus-pore at the end of the foot, readily separates this genus from Limax.
Besides these differences, the radula is of a different type. In Limax the breathing-
hole is situated near the hinder end of the shield, whereas in Arion it is much

346 MOLLUSCS.

further forward. In the present genus there is no internal shield-like shell, as
in Limax, but this is represented by a few unequal calcareous particles beneath
the mantle. Nine species of this genus are said to occur in Britain, and of these
the large A. empiricorwm is the commonest and best known. It is sometimes
intensely black, but it may be brown, red, yellow, greenish, or even white. This
great variation in colour is unaccountable, for black and red specimens occur in
the same districts where the natural surroundings are practically the same. The
edge of the foot, when crawling, displays a yellowish or orange border crossed by
closely-set black lines. This species usually feed on vegetable substances, but it has
occasionally been known to devour earthworms. It ranges over a considerable
part of Europe, and has been recorded from Siberia, Corsica, and as far as Madeira.
The genus Helix includes the true snails of the type represented by the
garden-snail (H. aspersa), and the edible or vine-snail (H. pomaiia), as it has been
variously named. The animal is completely retractile within its shell, and the
body distinct from the foot, and well protected by the spiral shell. The breathing-
orifice is on the right side beneath the margin of the aperture of the shell. The
genus Helix, as understood at the present time, is much more limited than it was
some years ago, and the tendency of conchologists is to propose still further
limitations. The necessity of dividing an enormous genus like Helix containing
thousands of species, is universally recognised, but the danger arises of carrying
this sectionising too far. Many of the divisions are partly founded upon
geographical considerations. The form of the shell in Helix is extremely variable,
as a glance at any collection will show. Some are sharply conical, others globular,
or flat and acutely keeled at the circumference; and the variety of colour is
endless, and changeable in specimens of the same species. The British H. nemoralis
and H. hortensis are striking examples ; and H picta, a beautiful Cuban shell, is
another remarkable instance. Not only does the ground-colour offer many
variations, but the colour and disposition of the spiral lines or bands which adorn
the surface are equally variable. The twenty-five species of Helix which occur
in Britain are insignificant in comparison with their exotic relatives, although
large enough to do a considerable amount of damage in the garden. The finest is
the H pomatia, popularly known as the apple-snail, but this name, as pointed
out by various writers, although appropriate as regards its shape, was not derived
from the Latin pomum, an apple, but from the Greek poma, signifying a lid or
operculum. When winter is approaching, the animal secretes a diaphragm or
covering to the aperture of the shell, a false operculum, to keep out the cold and
wet. when hibernating under ground. It is composed of slime and calcareous
matter, but is not pierced with a minute breathing-hole, as is the case in some
other species, although probably sufficiently porous to permit of whatever change
of air may be necessary during the winter sleep. The eggs of H. pomatia are
deposited in June in holes in the ground, formed by the snail itself. They are
about the size of a small pea, and much resemble in colour and consistency the
berries of the mistletoe. Only a day or two is occupied in the production of sixty
to eighty eggs, and these are then covered up with earth and the ground so
levelled that the place, or egg-nest, is difficult to discover. The length of time
before hatching varies according to locality and the state of the temperature. It

GASTROPODS. 347

may be from about twenty to forty days before the young snail eats through the
skin or shell of the egg, and this it is said to entirely consume. Although H.
pomatia is commonly styled the edible snail, it should be remembered that other
species are also considered a delicacy; H. aspersa, H. naticoides, and H.
vermiculata being commonly eaten in parts of Italy and Sicily ; while in Naples,
H. ligata and H. lucorum are also to be seen for sale. H. mazzullii, which is
collected near Palermo, possesses the power of boring into the rock ; this being
probably effected by means of the radula. The supposed object of these excava-
tions is to secure a place of refuge during the period of excessive heat, and also to
obtain a supply of lime for the formation of the shelL The Philippine Islands are
the home of a beautiful genus of snails (Helicostyla), many of which are clothed
with a peculiar periostracum, which, when wetted, becomes more or less transparent,
disclosing the colour of the shell beneath. Two or three of the species are of a
bluish tint, a colour not found among other land-shells.

The important genus Bulimus (now abolished in favour of Strophocheilus)
formerly contained a large number of species from all parts of the world, but is
now limited to a comparatively few forms occurring in South America ; 8. oblongus
being one of the commonest and best known species. Another, S. maximus, is
sometimes as much as 6 inches in length. The majority of the other species,
originally classed in Bulimus, are now located in Bulimulus and its sections, or in
Buliminus. These genera are distinguished by differences of the jaw and radula.

. ... There are several other families of land-shells, which can onlv

Other Families. . . J

be briefly referred to. The Cylindrellidce are very elongate, many-

whorled shells, which occur principally in the West Indies and South America ;

many of them being remarkable for their slender forms and exquisite sculpture. A

peculiarity of Cylindrella consists in the shell being almost invariably truncated,

that is, the upper whorls are broken off when the animal reaches maturity. This

may be done to lighten the shell, which otherwise would be too long for the

mollusc to carry erect. The Pupidce comprises a number of forms which are

conchologically very dissimilar. Th.e typical Pupa includes minute creatures, and

appears to be found in all parts of the globe, but especially in temperate and

mountainous regions. They are gregarious and live in moss, under stones, in the

crevices of old walls, or among the roots of grass and other plants. Most of the

species have what are called " teeth " within the aperture of the shell, and these in

some species are so numerous as to almost close the opening, and

thus make it, one would suppose, a matter of some difficulty for the

animal to squeeze through them when emerging from its shell.

Vertigo is a genus similar to Pupa as regards the shell, but separable

on account of the animal having only one pair of tentacles, the lower

pair being entirely wanting. The shells, according to the species,

are dextral or sinistral. Clausilia is remarkable for the large

number of species, the general similarity in the form of the slender

shell, and the peculiar process within it, which serves as a door to

shut in the animal when retracted. The shells are almost invariably reversed, and

furnished with two or three folds or plicae within the mouth, and other lamellae

still further within, which can only be detected by the transparency of the shell

348

MOLLUSCS.

itself. About a thousand species have been described. They are most numerous
in Europe and Eastern Asia, only a very few species being known from South
America. Achatina is one of those genera the scope of which has been greatly
altered since it was first founded by Lamarck. In those days any land-shell with
a notch or truncation in the pillar-lip of the aperture was considered an Achatina.
It is, however, now reserved for a group of large snails which are only met with
in Africa, Madagascar, and a few other adjacent islands. They have fine handsome
shells, vividly painted with more or less wavy stripes, and covered with a thin
periostracum. A. variegata, in the tropical forests of West Africa, is sometimes
T\ inches in length, and the largest of all the living land-shells.

The members of the extensive family Achatinellidai are inhabitants of the
Sandwich Islands, and occur in no other part of the globe ; the species being all
small, and many of them both dextral and sinistral. Some are found on trees

agate-s>'ail {Adiatina fulica).

and shrubs, whilst others are always met with on the ground. Mr. Barnacle has
given an interesting account of the production of musical sounds by these little
land-snails. He described the sound as resembling that of hundreds of iEolian
harps, and believed it was produced by the friction of the shells against the bark
of the trees upon which the snails were crawling.

The amber -snails (Succineidce) bear a strong family likeness to one
another. The shells are all very fragile, oblong, yellowish, or reddish, with a more
or less exserted spire and a very large body-whorl. They are found in damp
situations, and have even been observed crawling beneath the water, upon which
they can float in a reversed position. They are vegetarian in their diet, and
deposit their eggs on the stems and leaves of aquatic plants, and also upon stones
or other substances near the water's edge. Species of Succinea occur in most
parts of the world, being met with in such remote localities as Greenland,
Patagonia, India, Japan, Australia, and the South Sea Islands. The species

GASTROPODS.

349

figured on page 344 is found all over Europe, and ranges even as far as Afghanistan,
The character of the radula is shown in the figure on the next page.

The family Oncidiidce includes about fifty shell-less air-breathing molluscs.,
somewhat slug-like in general appearance, but provided with a thick mantle covering
the whole dorsal region. This is frequently more or less tubercular, some of the
tubercles being furnished with eyes which, simple as they are in structure, are
identical in type with those of the Vertebrata. These snails live on the seashore
or in brackish marshes, eating nothing but sand, but, of course, only digesting the
nutritious organic particles contained in it. Professor Semper has given an
account of their habits, and how they are pursued by certain fishes (Perioph-
thalmus), which come ashore after them. One species, 0. celticum, is found in
Cornwall and South Devon, others occur in America and the Pacific.
Basommato- The numerous forms belonging to this group, comprising the rest

phora. of the Pulmonata, differ from those already indicated, in having the
eyes situated at the base of the
tentacles, as in the marine whelks \ \ Vjhlf/)
and periwinkles, instead of at the
tips. An external shell is always
present, and capable of containing
the entire animal. The members
of the family Auriculidcb mostly
Eariet Shells, inhabit salt or brack-
Auricuiidse. j^ marshes, and were
formerly regarded as marine mol-
luscs. The shells generally are
rather solid, of different forms, but
usually with narrow apertures, more or less contracted by teeth. The internal
septa between the whorls of, the spire are often absorbed or dissolved, excepting

that between the last and penulti-
mate volutions. Some species of the
typical Auricula have large heavy
shells, and are met with in mud-
banks and in swamps, in the Indian
Archipelago. Those belonging to
Pythia have oval, compressed shells,
with toothed apertures, and occur
in great numbers in most places in
woods near the sea, are wholly ter-
restrial in their habits, and feed on
decayed vegetation. One member of
this family (Carychium minimum)
is found in Great Britain, and on the Continent. It is an extremely small
shell, less than the tenth of an inch in length, transparent, glossy, having
three teeth -like projections within the aperture. It hides away at the roots
of grass, among moss, dead leaves, or under stones or dead wood, in damp
situations.

Pythia scarabceus (nat. size).

earlet shell, Auricula judoe (nat. size

/

35°

MOLLUSCS.

Pond-Snails, etc.

EMBRYO OF RIVER-LIMPET {AncyluS

The three families Limnceidce, Physidce, and Chilinidoe form a
second group of the Pulmonates with sessile eyes, all being inhabit-
ants of fresh water, but rising occasionally to the surface to renew the supply
of air. They are mostly herbivorous, but some kinds of Limncea and Physa are
said to become carnivorous occasionally. In the first family the members of the
genus Ancylus are popularly known as fresh-water limpets, on account of the

resemblance in form of their shells to the true
limpets. They have all small thin shells, with the
apex somewhat posterior, but generally inclining
a little to the right or left. They are found on all
four continents, as well as in Australia, New Zealand,
the West Indies, and. other islands ; two species
being British. A. fluviatilis occurs generally on
stones, but occasionally on plants in shallow streams,
and running brooks, whereas A. lacustris invariably
adheres to the stems and leaves of plants in ponds, lakes, and canals. On account
of this difference of habit, and also for various anatomical reasons, the latter species
has been placed in a separate section (Velletia). The illustration represents the
embryonic stage of this species just prior to its quitting the ovum.

The fresh- water snails belonging to the genus Limncea have thin horny shells,
with more or less sharp spires, and are usually dextral, but certain forms occurring
in the Sandwich Islands, Australia, and probably other neighbouring localities, are
constantly sinistral, so that it is impossible to separate them from the genus
Physa by the shells only. An examination of the animals, however, at once
determines their proper position. In

Limnaa the two tentacles are com- 0^3Q^
pressed and triangular, with the eyes a
at their inner base. In Physa they
are cylindrical. The jaw and radula
are also different in the two genera.
The species of Limncea frequent
shallow and still waters, in most parts
of the globe, often swimming at the
surface of the water in an inverted
position. They are prolific and
gregarious, and the eggs are enclosed

in transparent gelatinous capsules, and deposited in continuous series, and attached
to submerged stones as well as to the stems and leaves of aquatic plants. L.
stagnalis, which is common in ponds, marshes, and slow rivers, is the largest species,
and six other species occur in Britain. The other figured forms illustrate the
great variation which occurs in the relative length of the spire and aperture. In
one of these (L. truncatula) the liver-fluke, so destructive to sheep, passes one stage
of its existence.

The animals of the genus Planorbis are small, and have the vital organs on
the left side. The tentacles are slender as in Physa, but there are no lateral
mantle-lobes. The shells are all very similar, being sinistrally and spirally coiled

row OF teeth of radula of — a, Limncea stagnalis ;
b, Ancylus fluviatilis ; c, Succinea putris. (Greatly
magnified.)

GASTROPODS.

35 1

up like a rope, in the same plane. They frequent stagnant pools and ditches, or
slowly running water, in all parts of the world. The well-known P. corneus is
not only by far the largest of the eleven British species, but also larger than any

common pond-snail (Limrwea).

other known form, although some of the South American types approximate
closely. When disturbed, it emits a purple-coloured fluid, probably as a means
of defence.

In Physa the animal is always sinistral, having the respiratory and genital
orifices on the left side. The tentacles are cylindrical, and the eyes are at their

VAEIOUS FORMS OF THE GENUS LIMN^A.

1, Limncea glabra ;" 2, L. palustris ; 3, L. stagnalis ; 4, L. truncatula ; 5, L. peregra ; 6, L. vulgaris ;

7, L. ovata ; 8, L. auricularia.

inner base, as in Limncea. The mantle is furnished on each side with more or less
elongate lobes, which, when the mollusc is crawling, are folded back upon the
exterior of the shell. In their habits these snails resemble the preceding genus, and
they are almost cosmopolitan in their distribution. Physopsis, a Central and South

15*

MOLLUSCS,

African form, has a reversed shell like Physa, but is distinguished by having a
tooth or fold on the columellar margin of the aperture. In Chilina the shell is

dextral, like that of Limncea,
but differs in being covered
with a periostracum, and ex-
hibiting reddish wavy colour
markings. The columella is
thickened and furnished with
one or more folds or plaits.
They are found only in clear
running streams of South
America.

The curious pulmonate
known as Amphibola some-
what resembles a periwinkle
in form. It lives between tide-
marks in brackish or salt
water, on mud -flats at the
mouths of rivers in New
Zealand, and is used as food
by the natives. It is abundant
in some places, and is a slug-
gish creature, subsisting upon
the vegetable matter contained
in the mud, large quantities
of which it passes through the
alimentary canal. Professor
Hutton says that it will live
for a week or ten days in fresh
water, and more than a fort-
night in salt water, without
being exposed to the air. The
breathing-orifice is situated on
the right side of the neck, and
the radula shows some affinity to that of Physa. The shell is solid, globular, with
a short spire and an oval aperture. The animal is furnished with a thin horny
subspiral operculum.

ramshorn snail (Planorbis corneus).

The Hind-Gilled Group, — Order Opisthobranchiata.

The Opisthobranchs form the second of the three main divisions of the
gastropods, and are all marine forms, having the sexes united in each individual,
and breathing chiefly by gills or branchiae This character at once separates them
from the Pulmonata, and the different positions of the branchiae, and their herma-
phrodite nature, serve to distinguish them from the Prosobranchia, the third and
last main branch of the Gastropods. In the Opisthobranchs the branchial veins as

GASTROPODS. 353

well as the auricle are placed behind the ventricle of the heart, but in the
Prosobranchs the branchial system is anterior to the heart. The majority of the
molluscs included in this order are unprovided with a shell in the adult state ;
but there are some exceptions, such as the shell-bearing Pteropods, and many of
the Tectibranchs. They are generally furnished with a pair of tentacles and labial
palpi, or an expansion of the skin like the veil of the larval form. To compre-
hend the character of the internal organisation, the above illustration should
be consulted. It represents a longitudinal section of the animal ; p is the foot ; a,
the mouth, covered above with the veil-like expansion, over which are the tentacles
c ; v shows the branchial veins carrying the blood to the gills, from which it flows
into the heart. This position is the opposite of that which characterises the
Prosobranchs. Another anatomical peculiarity, which may here be referred to, is
the direct communication of the system of blood-vessels with the surrounding
medium — a character common to most other molluscs, and on which depends the

circulation in Pleurobranchics aurantiacus.

changeable external appearance of the individual. In the illustration of Pleuro-
branchus, as above, g indicates the opening of a duct which conveys water direct to
the blood, and through which the blood-vessels permeating the back and foot, like
the holes in a sponge, can be filled or emptied at the will of the animal. Although
this, in the main, is the principle of the circulation in most Opisthobranchs,
one branch of the order possesses no special breathing-organ, respiration being
effected through the naked skin of the body. The Opisthobranchia may be
divided into three principal suborders, namely, Nudibranchiata, Tectibranchiata, and
Pteropoda.

Naked-Gilled Subgroup, — Suborder Nudibranchiata.

The naked-gilled Gastropods constitute a large assemblage of extremely
beautiful molluscs, of remarkable shape, and often brilliant coloration. The
distinguishing characteristic of the typical forms consists in the breathing-organs
being exposed on the back of the animal, and not protected by the mantle. Other
groups, however, are classed within this suborder, in which either the position or
character of the respiratory organs is different. The gills may be situated on
each side of the body between the back and the foot, or respiration be effected by
the ciliated surface of the body. For these and other reasons the Nudibranchs

vol. vi. — 23

354

MOLLUSCS.

have been arranged in four groups, Anthobranchiata, Inferobranchiata, Poly-
branchiata, and Pellibranchiata. A fifth group, Parasita, has also been proposed for
a very curious mollusc (Entoconcha), which lives parasitic within an echinoderm
{Synapta). Nudibranchs are found in all parts of the world, and are most
abundant in depths where seaweeds and corallines flourish, although they are also
found at low water or even between tide - marks. A few species have been
dredged at great depths. Some even pass their life in the open sea, attached to
floating seaweeds, or swim about freely like Pteropods or Heteropods.

The animals belonging to this group are characterised by their
'symmetrical form, and the position of the vent. This is placed upon
the posterior or central part of the back and surrounded by the branching gills,
which are more or less contractile. The body is protected above by a large dorsal
shield of a spongy texture, and made more or less rigid by calcareous spicules
which are embedded in it. The tentacles are dorsal, and retractile through holes

Anthobranchiata.

Doris Tribe.

Acanthodoris pilosa (magnified).

in the mantle some distance from the anterior extremity of the body, They are
smooth at the base, but lamellated towards the tip. The eyes are minute and
situated in the skin behind the tentacles.

A large number of species from all parts of the world, at one
time considered forms of the old genus Doris, are now placed in the
distinct group Doridopsidxn, on account of differences in the oral organs. The
general aspect of the animals of this family is the same as that of Doris, the gills
being arranged in a circle around the vent on the posterior part of the back. The
buccal mass or eating apparatus is small, without jaws or raf.ula, and organised for
suction. The extensive family Dorididw, contains a considerable number of
genera and subgenera, characterised by differences in the branchiae, the relative
proportion of the mantle in regard to the foot, and variations in the radula and
jaws The general aspect of the genus Doris is represented by the figure here
given of Acanthodoris pilosa. The species are very numerous, and some of them
are amongst the largest of all Nudibranchs. They are world-wide in their dis-
tribution, over twenty species occurring in British Seas. "When living, they are
most beautiful objects, and must be studied in that state, for when dead and
immersed in spirit, they so contract that their natural form can only be guessed,

GASTROPODS. 355

and all the beautiful and varied colours disappear. The spawn of Doris and other
Nudibranchs is deposited in the shape of a gelatinous band, always arranged in a
more or less spiral form, and fastened by one of its edges to corallines or the
under sides of stones. The ova are minute and very numerous, amounting in some
species to several thousands. Before the period of exclusion, the young may be
seen revolving on their own axis, by means of vibratile cilia, and on escaping
from the egg they swim about freely in the water by the same means. The larva
is extremely minute, and has more the appearance of a wheel-animacule than
a mollusc. It is enclosed in a transparent, calcareous, nautiloid shell, with an
operculum. Its structure is very simple, showing no signs of the external organs
that distinguish the future adult ; the principal portion visible outside the shell
being composed of two flat discs or lobes, fringed with long cilia, by the motion of
which it swims freely through the water. These are often withdrawn into the
shell, and the operculum is closed upon them when the animal is at rest. Boris
inuibilla, a fine handsome species, having a wide distribution in the Indian and
Pacific Ocean, is fully 4 inches long and 2 to 3 in width. It has been obtained at
the Seychelles, Andaman, and Samoa Islands. Bathydoris abyssorum was dredged
in the mid-Pacific, at a depth of two thousand four hundred and twenty-five
fathoms. It is a large animal, about 5 inches in length, of a nearly spherical form,
subgelatinous, subpellucid, and greenish white, with a dark purple foot. The
branchiae are non-retractile, and disposed in six groups. It forms a remarkable con-
necting link between the Tritoniidce and the Dorididce. In the genus Hexa-
branchus the gills are arranged in a circle round the vent, and are composed of
six separate plumes, each of which is retractile within a special cavity of its own,
and not within a common cavity as in Doris. The species are not numerous,
and have only been met with in warm seas, such as the Red Sea, and Indian
and Pacific Oceans. H. sandwichensis, a handsome species of a pale crimson tint
occurring at the Sandwich Islands, is nearly 6 inches in length when alive.

The family Polyceridce is distinguished from the Dorididce by having non-
retractile gills; the principal genera being Goniodoris, Acanthodoris, Idalia,
Ancula, Polycera, Plocamophorus, Triopa, and jEgirus. Ancula cristata is an
elegant little creature, about half an inch in length, occurring upon most of the
British coasts. It is white, with the processes tipped with yellow or orange.
The tentacles are laminated and non-retractile, each having two styliform
appendages at the base. The gills are placed in the middle of the back, on each
side of which there are a few compressed appendages.

This division of Nudibranchs was established for a group of
Inferobranchiata. » i

naked marine molluscs having the gills placed symmetrically along-
each side of the body between the margin of the dorsal mantle and the edge of the
creeping disc. Phyllidia and Pleurophyllidia are the typical genera originally
described, and may be regarded as the principal representatives of this group of
molluscs. One group of Inferobranchs, however, is abnormal in being destitute of
external branchiae. In the genus Phyllidia, containing several very handsome
species, the animal is somewhat depressed, and covered with a leathery and sometimes
tuberculated mantle ; the head is small and concealed between the foot and back ;
and the two oral tentacles are short, the dorsal pair retractile into cavities towards

356

MOLLUSCS.

the anterior end of the body as in Doris. The laminated gills extend the entire
length on both sides. The vent is dorsal and at the posterior part of the mantle,
and the reproductive organs are on the right side. In the disposition of the
branchiae these animals are very like the chitons and limpets. They are remark-
able for possessing neither jaws nor radula, the mouth being modified into a sucker,
as in the Doridopsidce. These animals are so apathetic that they have never been
observed to make any movement, but appear as if dead. They are inhabitants of
tropical seas, the few species that are known occurring in the Red Sea and the
Indian and Pacific Oceans. In the allied Pleurophyllidia the animals have at the
anterior end a sort of shield above the head. The gills are situated as in
Phyllidia, but the vent is on the right side. The mouth is provided with two
strong jaws, and a well-developed radula. The dorsal tentacles are small, and
situated between the mantle (notceum) and the head-shield, and not passing through

Ancula cristata (much

the mantle, as in Doris or Phyllidia. P. lineata, from the Mediterranean, is a
typical form of this genus. It is about 2 inches in length, of a golden colour,
with longitudinal parallel whitish lines on the dorsal mantle.

This division of the Nudibranchs contains some of the most
' beautiful species of the entire order ; and includes those forms which
have the dorsal branchial processes arranged along the sides of the body, and not
grouped around the vent, as in the Anthobranchiata. They have no spicula
embedded in the skin. The branchial processes are sometimes simply cylindrical
or linear, papillose or fusiform, but in other cases conspicuously branched.
vEolidia is an example of the group in which they are unbranched, and Dendro-
notus exemplifies those in which the gills are branched. Tethys, Melibe, Tritonia,
Scyllcea, Glaucus, and Doto, are, besides those already mentioned, some of the best
known genera of the Polybranchs. Tethys leporina is a curious-looking animal,
met with in the Mediterranean. The body is swollen, almost colourless, and trans-
parent like the gills, contrasting wonderfully with the red-tipped dorsal processes

GASTROPODS.

357

and the blackish irregularly white-edged dorsal
escent in the dark, and the phosphorescence at
any way disturbed. It is said to be
lively in its movements, and capable of
swimming freely in any direction ; but
has neither jaws nor radula. Specimens
are sometimes captured 8 inches to a
foot in length. In the genus Tritonia
the branchiae are numerous, and arranged
in a row along the lateral margins of
the back. There is a large frontal veil
above the mouth as in Tethys,, and the
retractile tentacles are branched at the
ends. The horny jaws are large, and
the radula well developed. T. hombergi
is the largest of the British nudibranchs,
being sometimes 7 or 8 inches in length.
It varies in colour from dark purple-
brown to light brown, flesh-colour, and
yellowish white. Dendronotus arbor-
escens is one of the most beautiful of
the naked Mollusca, the accompanying
figure giving a good idea of the
branched character of the gills. It
will be noticed that they are arranged
along each side of the tapering body,
that the head-veil is also branched, and

eye-spots. It is vividly phosphor-
once appears if the creature is in

Dendronotus arborescens (enlarged)

Tethys leporina.

that the laminated
tentacles are retractile
within branched
sheaths. The back
is reddish or yellowish
brown, marbled with
darker brown, and
spotted with white.
The animal is about 2
inches in length, and
has both jaws and
radula. It is not
uncommon on most
parts of the British
coasts, from low- water
mark to deep water,
and it also ranges
northward to Green-
land. It is also re-

358

MOLLUSCS.

corded from the Atlantic coasts of North America, north coast of France, and some
parts of the Baltic. The animals belonging to the genus Scyllcea live upon floating
seaweed out on the high seas ; S. pelagica being usually found upon the gulfweed
of the Atlantic, which it resembles in its coloration. The foot is narrow, the sides
being thin, and capable of clasping the stems of the seaweed. The body is much
compressed laterally, and produced into two large leaf-like appendages on each side
of the back, on the inner surface of which the tufted branchial processes are situated ;
a median supra-caudal crest also bearing branchial filaments. The tentacles are
slender, laminated, and retractile within long compressed trumpet-shaped sheaths.
The genus contains only a few species, but it has been found in almost every sea.
Phyllirhoe is a genus of Nudibranchiata remarkable for the absence of both foot
and gills. The body is compressed laterally, and so translucent that all the internal

Phyllirhoe bucephala in the light, showing internal anatomy (greatly magnified).

anatomy is visible. These animals are pelagic and eminently phosphorescent.
Specimens kept in aquaria have been observed to be instantly luminous if
touched.

In the jEolidiidce the body is slug-like and tapering posteriorly. There are two
labial and two dorsal tentacles, and the dorsal branchial papillae are cylindrical or
fusiform, and arranged in transverse rows on the sides of the back ; the front of the
creeping disc is often produced on each side in the form of tentacles ; the horny
jaws are large, and the radula consists generally of a single series of spinous plates.
jEolidia papillosa, the largest of the British species, may be found under stones
between tide-marks on many parts of the coasts. It is brown, grey, or orange,
spotted with brown or purple and white ; the dorsal tentacles are brown with
white tips, and the papillae are speckled with brown or lilac and white, with
white tips. These molluscs are animal-feeders, partial to sea-anemones. Their
fecundity is very great, as many as sixty thousand eggs being deposited by a
single individual at one time. These are enclosed in a perfectly transparent

GASTROPODS.

359

mucus, and the fry generally emerges in about ten days or a fortnight. Like
Scyllcea, the animals known as Glaucus live in the open sea upon floating
seaweed, and feed upon jelly-fish of various kinds. The form of the body
is peculiar, having three lobes or expansions on each side, supporting the linear
branchiae. Pelagic animals generally seem to be either colourless or specially
coloured, with a view to protection from enemies both above and below the surface

jEolidia papillosa.

of the water. Probably the blue colour of lanthina is protective, as resembling
that of the ocean water. The blue tint of Glaucus may also serve this purpose.

This group of Nudibranchs comprises a number of forms which
have no external branchiae, but effect respiration through the general
ciliated surface of the body. A typical example of this section is illustrated by
the accompanying figure of Elysia viridis which is a little creature about an inch

Pellibranchiata.

Elysia viridis (magnified).

in length, of a dark green colour, varied with white, greenish blue, and reddish
white dots. It lives upon seaweed, and, owing to its colour, is difficult of obser-
vation. The absence of external branchiae is noticeable, and the ramified blood-
vessels seen in the lateral expansions of the body are presumed to be connected
with the respiratory function. This is the only species found upon the shores of
Britain, and is most common on the south and south-west coasts. It is said to mimic
the colour of the different seaweeds upon which it occurs. Limapontia is another

36°

MOLLUSCS.

example of the Pellibranchs. It is slug-like in form, but without any tentacles.
The species figured (L. capitata) is a minute animal, about a sixth of an inch in length,
chiefly of a black colour, but occasionally somewhat transparent and colourless.
Alder writes that " this curious little animal is probably pretty generally diffused,
but on account of its minute size it may readily be overlooked. It is gregarious ;
and, wherever met with, it has usually been found in abundance, appearing when
contracted like little black dots scattered over the conferva on which it feeds."

Limapontia capitata (much magnified).

It lives between tide-marks, feeding upon small algae, and deposits its ova in small
pear-shaped capsules, each containing about one hundred eggs.

The only form belonging to this group, the position of which is
not settled, is the parasitic genus Entoconcha. The animal is worm-
like and spirally coiled, and attaches itself by the oral end (a) to one of the
blood-vessels (E), within the visceral cavity of a certain group of Echinoderms.
One species is found in Synapta, and a second (E. muelleri) occurs in the
trepang (Holothuria) of the China Sea. In the very early or larval state Ento-
concha is contained in a minute operculated glassy shell. The subsequent changes
between this and the perfect condition have not yet been observed. It is the
lowest type of Nudibranchiata, if indeed it really belongs to that suborder, which
is not absolutely certain, some authors even locating it near Natica. Were it not
for the form of the larva, one would hardly have supposed that this worm-like
creature belonged to the Mollusca at all. It has neither jaw nor radula, but the
mouth is adapted for sucking. The sexes, as in the typical Nudibranchs, are
united in the same individual. The female element (6) is somewhat anterior, the
male organ (c) being at the opposite extremity. The central portion of the animal
serves for a certain time as a nursing-pouch for the embryos, which subsequently
are extruded at an opening at the posterior end. Only one out of every hundred
or two hundred specimens of Synapta is infested with the Entoconcha. Pelseneer
locates it next to Eulima among the Pectinibranchs.

Covered-Gill Subgroup, — Suborder Tectibranchiata.

This constitutes the second suborder of Opisthobranchiata, and includes
certain molluscs characterised by the possession of a lateral gill, protected by
the mantle, or a shell. The members of the group are hermaphrodite animals,
and differ from the Nudibranchs, not only in their respiratory organs, but
also in the possession of a true mantle, which, in the Nudibranchs, is repre-
sented by the dorsal shield. On the other hand, they show affinity with certain

GASTROPODS.

361

Nudibranchs in regard to the position of the rhinophores, the lateral expansions
of the body, and the radula. Nearly all the Tectibranchs possess a shell which
sometimes is wholly concealed beneath the mantle, sometimes partly covered,
and, in many instances, wholly external. Some are carnivorous, others entirely
phytophagous or vegetable-
feeders; they mostly progress
like an ordinary snail by means
of the foot, but a few of them
are free swimmers. The ova
are generally deposited in long
ribbons more or less coiled, and
the embryos are provided with
an operculated spiral shell. The
Tectibranchs are classified in a
number of families, separated
from one another by differences
in the general conformation of
the animals, the shell, and the
radula. The following are the
more important genera: —
Actceon, Scaphander, Bulla,
Acera, Aplustrum, Ringicula,
Gastropteron, Philine, Doridium,
Aplysia, Lobiger, Pleuro-
branchus, Umbrella, and the
aberrant Siphonaria. Actwon,
of which about thirty species
are known, is found in all seas.
The animals are provided with
a sort of head-shield, which is
notched behind, and have the
sessile eyes in front of the notch.
They all are furnished with an
ovate, often spirally punctate
shell, which in some cases is
prettily striped or spotted, and is
capable of receiving the entire
animal when contracted. In
Scaphander the animal is too
large to be wholly contained
within the shell, and has
an enormous head -disc ; and the sides of the body are produced into lobes or
epipodia, which can be partly reflexed over the shell. It has no visible eyes,
as these would scarcely be of service to an animal which burrows into mud and
sand in search of its food. Unlike many of the carnivorous Gastropods, which
bore a hole in the victim's shell, and suck out the contents, Scaphander bolts

Synapta digitata, with parasitic Entoconcha, and middle

PORTION ENLARGED.

362

MOLLUSCS.

its prey whole, shell and all. The shell is then broken up by the aid of a very re-
markable gizzard, and the soft parts digested. This gizzard consists of three strong
calcareous plates of different size and form, which grind against one another by

powerful muscles. The shells of Scaphander
are mostly thin, spirally striated, oblong,
convolute, without any visible spire, having
the aperture narrow behind, and much wider
in front. The known species are not
numerous, and occur chiefly in seas of the
Northern Hemisphere, but a few have been
described from other parts of the world.
S. mundus was obtained at the Aru Islands,
at a depth of eight hundred fathoms, and
& gracilis off the Azores, in one thousand fathoms. By far the largest known
form is the common British S. lignarius, which ranges from Finmark to the
Mediterranean.

The bubble-shells (Bullidw), as this group is popularly called, are something
like Scaphander in form, but rather rounder and stronger in their structure.
Most of those belonging to the typical genus Bulla are prettily painted with
blotches, clouds, and dots. The animal is not too large for its shell, has distinct
eyes, and a different type of radula to that of Scaphander, which these molluscs
resemble in their predatory habits. Another genus is represented in Britain by

larva OP Entoconcha (much magnified).

Acera bullata (twice naft size).

Acera bullata, which occurs on oozy ground and mud-flats in many estuaries. It
also ranges from Finmark to the Mediterranean; and is remarkable for its thin, horny,
convolute shell, with a slit at the suture, through which the animal protrudes a
long, thread-like mantle -appendage. The side -lobes are largely developed, and
can be reflexed so as to completely envelop the shell. They are also employed in
swimming. Another family is represented by Ringicula, all the members of
which are very small, not a quarter of an inch in length. The shells are entirely
white, more or less globular, with a pointed spire, and with the aperture* — which is
notched in front — to some extent contracted with folds. The channelled character
-of the aperture is rather exceptional, the shells of the Tectibranchs being almost

GASTROPODS.

363

exclusively holostomatous, that is, with uninterrupted apertures. Gastropteron,

which typifies another family, is remarkable for the great lateral expansions, or

epipodia, which are used by the animal in swimming, The gill lies exposed on

the right side, the head-shield is truncate in front and pointed behind, and the

mantle terminates behind in a slender, whip-like appendage. At one time this

mollusc was supposed to be shell-less, but in reality an internal shell does exist ;

but, as it is only ^0- of an inch in diameter, it may be easily overlooked. G.

meckeli, of the Mediterranean, is of a vivid red colour, with

a few white spots, and a pale or bluish border to the lobes.

In the Philinidce, as typified by Philine, the shell is very

thin, and wholly concealed beneath the mantle. In form

it somewhat resembles Bulla, but has the aperture larger.

P. aperta, a very common British species, lives in shallow

water all round the coast, feeding upon foraminifera and

even small sea-urchins. The animal is white, has a very

large frontal-shield, but no tentacles or eyes. It is provided,

as in the case of Scaphander, with a powerful gizzard. The ova, which are very

numerous, are deposited in a single series, in a long and loosely -twisted cord,

enclosed within an ovoid, gelatinous capsule.

The sea-hares (Aplysiidai), so called on account of a slight resemblance to a
crouching hare, and not for their nimbleness of foot, are elongate creatures, with
a long neck, distinct head, oral and dorsal tentacles, and furnished beneath the
mantle with a shelly plate to protect the branchiae. The mouth is provided with

Philine aperta (nat. size).

sea-hare, Aplysia (nat. size).

horny jaws, and the gizzard is armed with horny spines, which prepare the food
for digestion. The sides have large thin lobes, which are either folded over the
back, or used in swimming. Aplysia includes both animal- and vegetable-feeders,
inhabiting shallow water in all parts of the world. In olden time there were
many stories in vogue respecting the poisonous nature of the sea-hare, but it has
been shown to. be harmless. It has the faculty of emitting a nauseous smell ; and
a beautiful purple fluid is discharged from glands in the edge and inner surface
of the mantle. The species illustrated (A. depilans) occurs on the coasts of France

364 MOLLUSCS.

and in the Mediterranean. It is reddish brown, with irregular and variable
greyish blotches and spots. It occurs in numbers on the Portuguese coast,
and in stormy weather is sometimes cast upon the shores in such quantities as to
be the cause of epidemics, and almost to render it worth while to extract the purple
for economic purposes.

Of another family (Oxynoidce), we may take as an example Lobiger, which
includes elongate molluscs provided with a thin transparent shell, and having on
each side of the body two long parapodia, used as fins in swimming. The animal
has the power of casting off these lobes, and probably the posterior end of the
foot can also be spontaneously detached. Four species have been described from
the Mediterranean, Ceylon, Guadeloupe, and the Society Islands. They are
separable on account of certain differences in the soft-parts, but in a conchological
point of view they appear to be indistinguishable. In the family Pleurobranchidce,

the typical genus Pleurobranchus contains a
number of species from many parts of the
world, two of which occur on the British
coast. The one illustrated (P. peroni) is a
native of tropical seas, and was originally
obtained from the Mauritius. The body is
convex, ovate, with the mantle extending
over the back, and having a free margin at
the sides. Beneath this, on the right side, is
situated the large branchial plume. The
head is furnished with both labial and upper
tentacles, and at the inner base of the latter
Pleurobranchus peroni (nat. size). are situated the eyes. A thin, membranous,

flat shell is concealed beneath the mantle,
over the back. P. (oscanias) membranaceus and P. plurnula have both been
found on various parts of the British coast. Both range as far as the Mediter-
ranean. The spawn of P. plumula is deposited in ribbon-like and spirally arranged
masses,"resembling those of Doris.

The animal of the genus Umbrella, which typifies another family, is very
large, and carries upon its back a flat, circular, external shell, recalling the form
of an umbrella of the Chinese pattern. The gill, as in Pleurobranchus, is on
the right side, beneath the mantle, and protected by the shell. This unsightly
creature is remarkable for the enormous development of the foot, which extends
everywhere beyond the margin of the shell, and practically encloses the head in
front. One species occurs in the Mediterranean, and three or four others are met
with in the Indian and Pacific Oceans. The shell of U. indica is sometimes fully
5 inches in diameter,

The families Siphonariidce, Gadiniidce, and Amphibolidce, already mentioned,
constituted, until recently, a suborder of Pulmonata, to which Gray gave the name
Thalassophila. According to Haller, however, Siphonaria and Gadinia should be
regarded as modified Opisthobranchiates, and placed next to the Umbrellidce ; but
their systematic position cannot be considered definitely settled. The Siphonariidce
look like ordinary limpets, and attach themselves to rocks in the same way at

GASTROPODS. 365

about high-water mark. The shells are distinguishable by a groove on the right
side of the inner surface, interrupting the muscle by which the animal is attached.
Siphonaria much resembles Auricula as regards the pulmonary cavity, which is
adapted for breathing air or water, there being both a lung and a modified gill. It
is, however, protected or closed by a valve-like lobe of the mantle. The horny
jaw has a smooth and curved cutting edge. The radula consists of a single central
or rachidian tooth and numerous laterals, very similar in type to that of certain
groups of Pulmonata. About fifty species are known. The genus has an extensive
range from Vancouver Island in the north to Cape Horn in the south. One species
occurs on the coast of Portugal, but the majority inhabit eastern seas. In Gadinia
the breathing-chamber is without any sign of branchiae. It is a limpet-like animal
with a circular foot by which it attaches itself to rocks or stones, in the same
manner as limpets. It is probably a poor traveller. The pulmonary orifice is
placed on the right side near the head, and is closed by a small valve. The head
is large, without tentacles, with the sessile eyes placed at the sides. Mr. Dall, who
watched a colony of G. reticulata, noticed that " as long as the rock on which they
were remained damp, they continued with the margin of the shell firmly applied
to it. As soon as the boulder became dry, under the hot sun, I perceived a simul-
taneous motion in the colony. Each shell was raised above the surface of the
stone, the head and foot were protruded, and the orifice of the pulmonary cavity
was expanded. They were evidently enjoying the warm air."

Suborder Pteropoda.

Until within the last few years, the molluscs included in this suborder were
considered to constitute a separate class. Some systematists located the group
near the Cephalopoda, others, believing them to be of a more degraded type than
the Gastropoda, assigned them a position between that class and the bivalved
Mollusca. Dr. Morch and others, long ago pointed out the affinity of the
Pteropods with the Opisthobranchs, and Dr. Pelseneer has come to the con-
clusion that these molluscs should be included in two of the Tectibranchiate
groups of the Opisthobranchs. The Pteropods seldom come near land, except
when driven by currents and tempests, and although they rise to the surface
principally at night, they have been observed during the daytime. They are
characterised by two delicate fins or lateral expansions of the foot (parapodia),
placed at the anterior end of the animal, and used in swimming, being moved with
considerable rapidity, like the wings of a butterfly. When they wish to sink,
their fins are contracted, and the anterior part of the body, in some cases, is more
or less withdrawn into the shell or the mantle, and they thus fall to the depth
desired. At times they remain stationary, by keeping the fins merely extended.
Some — Clio, Pneumoderma, for example — adhere to floating bodies by means of
oral appendages provided with suckers, others by means of a sufficiently developed
foot. The fins, termed epipodia by Huxley, are sometimes united, forming a single
disc, sometimes partly connected, or, finally, entirely separated. The Pteropods
are hermaphrodite, or have the sexes united in each individual. They deposit their
ova in the form of long bands which float on the surface of the sea. They are

3 66 MOLLUSCS.

carnivorous in their habits, and live upon minute animals which abound in the sea,
including small Mollusca, and Entomostraca and other Crustacea. Some of them
possess prehensile organs for seizing their prey, but many appear to be totally
unprovided with any special appendages for this purpose. In the early stages
of development a shell always exists, but when adult, only certain forms are
furnished with such protective covering, the others being naked molluscs. They
possess a heart, consisting of auricle and ventricle, enclosed within a pericardium.
The branchise are either internal or external. The head, distinct in some groups,
and furnished with one or two pairs of tentacles, is practically wanting in others,
and reduced to a mere mouth at the base of the fins. Nearly all the various forms
have a radula, and some horny jaws. There are no eyes, or these are only repre-
sented by minute pigment dots upon the visceral sac, or on the tentacles. The
fry of the Pteropods closely resembles that of ordinary Gastropods; but sub-
sequently the frontal veil of the Pteropod disappears, and is replaced by the
parapodia or permanent fins.

The number of species of this group is inconsiderable, and may be estimated
at about fifty-four; but, as regards individuals, the numbers are inconceivable.
The bottom of the sea in various parts of the Gulf of Mexico, the Bay of Biscay,
and the Mediterranean, is paved with an accumulation of the dead shells of
Cavolinia, Cleodora, and other forms. Their tiny forms occur in shoals in the
tropics, and in more temperate seas, and, even in Arctic latitudes, they exist in
such myriads as to discolour the water for considerable distances. They there
form a large item in the diet of the Greenland whale. Some of the species have a
wide distribution, occurring in the Atlantic, Pacific, and Indian Oceans, others are
more localised.

The Pteropoda are divided into two sections, namely, Gymnoso-
Gymnosomata. L . ., . *

mata and Thecosomata. The animals belonging to the former group

have no mantle or shell in the adult state. The body is generally elongate, the head
distinct, and furnished with two pairs of tentacles, the posterior bearing rudimentary
eyes. The swimming-lobes are attached to the sides of the neck, which is somewhat
narrowed and constricted. The breathing-organ is external, lateral, or at the
posterior end of the body. The foot is rudimentary and ventral. The radula is
composed of numerous rows of teeth as in some of the Nudibranchs. The young
at first are contained in a minute straight shell, and swim by means of a ciliated
frontal veil (velum). Subsequently these structures disappear, and the larva pro-
gresses by means of circles of cilia which surround the body at intervals. In the
final metamorphosis, the cilia disappear, the parapodia are developed, and the animal
assumes the adult condition. The gymnosomatous Pteropoda are only few in number
of species, but, like the rest of the group, occur sometimes in enormous numbers, and
are very widely distributed. All are small creatures, the largest not exceeding an
inch and a half in length ; they are carnivorous, and often, it is said, feed upon
their shell-bearing relatives. The position assumed by the Gymnosomata when
swimming is vertical, with the head uppermost, or else slightly sloping.

The Gymnosomata are arranged in five families, comprising only seven genera,
namely, Dexiobranchcea, Spongiobranchcea, Pneumoderma, Clionojysis, Noto-
branchcea, Glione, and Halopsyche. Dr. Pelseneer locates them next to the Aplysiidce.

GLASS SPONGES.

GASTROPODS.

367

Thecosomata.

The forms belonging to this section of Pteropoda are characterised
by the presence of a delicate external shell, by the foot being repre-
sented only by the two anterior symmetrical fins, by the existence of a mantle,

by the absence of eyes, and (except in a

few cases) of a gill. The head is indistinct

and furnished with a single pair of

tentacles. The mouth is unprovided with

hook-sacs, as in the Gymnosomata. The

radula has only a single lateral tooth on

each side, with a small basal piece. The

Thecosomata are divided into the three

families, Limacinidce, Cymbuliidw, and

Cavoliniidcs.

The members of the family Lima-

cinidce possess a small sinistrally coiled

shell, provided with a delicate glassy

operculum, which is attached to the

posterior lobe of the foot. The animal

can withdraw completely within the

shell, which, when the animal is swim-
ming, has a lateral position, or possibly

rests with the spire inclining somewhat

downwards. Two genera are included

in this family, namely, Limacina and

Peraclis. In Limacina, of which ten

species are known, the shell is rather

globose, umbilicated, with a short spire,

and the aperture somewhat prolonged at the base. The lip of the aperture is

simple, but the columella is reflexed. The fins of L. helicina are broad and

squarish at the ends and notched on the inner edge. The operculum is oblong,
transparent, paucispiral, the nucleus being lateral. This
mollusc lives in immense shoals in the Greenland seas, and
it is one of those fed upon by various whalebone whales.
Two species only are known of Peraclis. The shells are
excessively fragile, sinistral, rather like a fresh-water Physa
in shape, but having the aperture produced below into an
acute rostrum. The animal has a minute glassy operculum,
and differs from Limacina in having a distinct head, pro-
longed into a proboscis, and other anatomical characters.
Both forms occur in the Atlantic, but P. reticulata is also
known from the Pacific and the Mediterranean.

The molluscs of the family Cavoliniidce have external,
semi-transparent shells, which are non-operculate, bilaterally
symmetrical, and not spirally coiled. They are variable in

form in the different genera. The animals are completely retractile within the

shell, and the form of the fins and of the hinder lobe of the foot varies consider-

laeva OF Pneumoderma (magnified).

Clione (somewhat enlarged).

368

MOLLUSCS.

ably. The mouth, lips, and tentacles are the same as in Limacina. Three genera
are comprised in this family, namely, Clio, Cuvierina, and Cavolinia. Clio
is subdivided by Dr. Pelseneer into four groups, Creseis, Hyalocylix, Styliola, and
Clio. In Creseis the shell is elongated conical, circular in section, smooth, and the
embryonic portion marked off by a deep constriction. The shell of Hyalocylix
is elongate, conical, oval in section, with a recurved apex, and marked with trans-
verse grooves and ridges. H. striata, the only known species of this genus, is
cosmopolitan. Styliola has a slender tapering shell, sometimes an inch in length,
and not more than a sixteenth of an inch in diameter at the aperture. It appears
quite smooth and glossy, and, like Hyalocylix, occurs in all tropical seas. Clio is

one of the most beautiful of all Pteropods.

US. The shell is often rather triangular in shape,
keeled along the sides, the lateral angles
being sometimes produced into long, straight,
sharp spines. It is of a most delicate glassy
substance, and highly glossy. The so-called
genus Balantium is synonymous with this
group. Eight species are recognisable. The
genus commonly known as Cuvieria contains
only a single species (C. columnella), which
has been obtained in the Atlantic, Indian,
and Pacific Oceans. It is glassy, excessively
thin, somewhat cylindrical, but produced
posteriorly to an acute point. This narrowed
portion is generally wanting in adult shells.
In the soft-parts it closely resembles Clio,
and it is chiefly on conchological grounds that it is separated. The genus Cavolinia
is perhaps the commonest of all. The shell is generally pale horny brown, often
globose, composed of a ventral and dorsal plate, which are united inf eriorly, but
not along the sides or above. The dorsal piece is flattish, and the ventral generally
very globose. The shell is produced into a spine behind, and the
sides generally terminate posteriorly in sharp points or spines.
The animal somewhat resembles Clio in its external characters,
but is remarkable for the presence of lateral prolongations of the
mantle, which project through the lateral slits in the shell.
Eight species are recognised by Dr. Pelseneer. C. tridentata, C.
uncinata, C. globosa, and C. trispinosa are the best known.

In the family Cymbuliidce the shell is very different from
that of other Thecosomata. It is cartilaginous or gelatinous,
bilaterally symmetrical, and somewhat resembles a slipper in
general form. It is very easily detachable from the animal, and consequently a
number of species, which in reality belong to this family, have been characterised
as shell-less. Pointed at the ventral extremity and truncated at the dorsal
end, it is covered with acute spine-like tubercles arranged in longitudinal series.
The modified foot, or fins, are large and rounded. The animal is furnished with
a radula. Of Cymbulia, two species are known. C. peroni is common in the

Cavolinia tridentata.

larva OP Cavolinia
gibbosa.

GASTROPODS.

369

Mediterranean, and it probably also occurs in the Atlantic. The second species, of
which only the shell is known, was found in New Zealand. Cymbuliopsis and
Gleba are the two remaining
genera of this family.

Front - Gilled Group, —
Order Prosobranchiata. A m '■■

The Prosobranchs, which
include the majority of
marine gastropods and a
few groups of terrestrial
forms, are always contained
within or protected by a
shell, and organised for
crawling. The branchial
or pulmonary cavity is in
advance of the heart, and
the auricle of the latter in

Gleba cordata. a, Body

b, Fin ; e, Proboscis.

front of the ventricle. This important anatomical
character, which is expressed or referred to in the term Prosobranchiata, can best

be understood by observing the accompany-
ing figure representing the male of one of
the periwinkles (Littorina). Here the
respiratory organs are lodged in a chamber
formed by the mantle behind the head ; the
gills are variable in the different suborders,
In some forms, with nonspiral shells, they
are double and symmetrical, but, in others,
and these are the majority, where the shell
assumes a spiral form, the gill is usually
single. Some of the Prosobranchs have
horny jaws, but others are without ; most
are furnished with a radula, but this is
sometimes absent. Characters derived from
this organ have been largely employed in
the classifications of the suborders. The
sexes are separate ; the head is distinct, and
furnished with a pair of tentacles, sometimes
having the eyes at the ends, but mostly at or
near their base. An operculum, which is
unknown among the Opisthobranchs and
Pulmonates, except in the case of Amphibola,
is developed in the majority of Prosobranchs,
but the number of genera in which this
appendage is absent is considerable. It assumes very different forms, and its size is
very variable in proportion to the dimension of the aperture of the shell. In some
vol. vi. — 24

ANIMAL OF MALE PERIWINKLE, WITH THE SHELL
REMOVED.

a, Mouth ; 5, Sexual organ ; c, Reflexed mantle ;
d, Vent ; e, Kidney ; /, Slime-gland ; g, Gill ;
h, Heart ; in, Shell-muscle ; p, Foot.

37o MOLLUSCS,

genera it is as large as the aperture of the shell (Ampullaria, Natica, Bithynia),
while in others it only partly closes it ; and in other cases it is so small as to be of
no use for closing the shell. It is mostly horny, but in a few instances is more or
less thickened and strengthened with a shelly or calcareous layer. The horny
opercula are mostly flattened, but in a few cases are thickened, or conical (Torinia,
Codojpoma). The shells of Prosobranchs comprise some of the most beautiful, and
most prized by collectors. The order may be separated into three main divisions,
namely, Pectinibranchiata, Heteropoda or Nucleobranchiata, and Scutibranchiata,
severally characterised by differences, as the names imply, in the breathing-organ,
coupled with other characters in connection with the genital organs, radula, etc.

Suborder Pectinibranchiata.

The molluscs included in this suborder have the body twisted, and contained
in a spirally-coiled shell. They are chiefly aquatic, and mostly marine, but a few
families are strictly terrestrial. The gills are comb-like, that is, consist of plates
arranged side by side and attached to a common stem, like the teeth of a comb to
the thickened back. They are situated in a vaulted chamber, formed by the mantle
over the neck, which is open in front for the admission of air or water. The
Pectinibranchs have been subdivided into several sections, founded upon modifica-
tions of the radula or lingual ribbon. The following are the most important in
the arrangement adopted by Paul Fischer, namely, Toxoglossa, Rhachiglossa,
Taenioglossa, Ptenoglossa, and Gymnoglossa. A large proportion of the Pectini-
branchs are furnished with a long proboscis, extensile and retractile at the will
of the animal. In almost every instance, molluscs of this proboscis-bearing group
are provided with shells which may be recognised by a notch or canal at the front
of the aperture, through which the so-called siphon is protruded. This consists of
a more or less elongate fold of the mantle, and conveys the water to the branchiae.
In another large section of the Pectinibranchs — Rostrifera — there is no extensile
proboscis, but the head terminates in a more or less prolonged snout which is not
retractile, and is termed the rostrum. These two groups, however, are now
abandoned on the ground that better characters are furnished by the radula.

SECTION TOXOGLOSSA.

In this group, including the families Conidce, Terebridce, Pleurotomidm, and
Cancellariidce, the radula is composed of two rows of long, barbed, marginal teeth.
The cones (Conidce) form an extensive family, containing about five hundred and
fifty species. They have always been great favourites with collectors, on account
of the great beauty and variety of the colour-markings, and are almost exclusively
tropical, only a few species ranging northward to the Mediterranean and Japan.
Some of them have a very wide distribution, being found in the Red Sea, Indian
Ocean, and in various parts of the Pacific. Others, on the contrary, have an
equally limited range. These animals are all predaceous, having a short strong
foot, truncate or square in front, and pierced with a water-bearing pore at the
anterior part. The head has two slender tentacles, with the eyes on the outside

GASTROPODS.

37i

textile COKE, Conus textile (nat. size).

near the middle. The siphon is long, and protruded through the notch at the
anterior or narrow end of the shell. They are not very active creatures, but crawl
about slowly in holes in the rocks, or fissures of coral-reefs, in depths ranging from
low-water mark to thirty or forty fathoms. The shells are generally strong and
solid, and as the animal grows and requires more room, it absorbs the early whorls,
leaving only a very thin partition between them ; but, in order to preserve the
proper weight of the shell, it thickens up the spire within. All the species are
formed on one plan, but the extremes vary considerably in form. This variation,
difference of sculpture, periostracum, and colour, constitute the characters upon
which the species are founded.
Some of the handsome and
rarer forms fetch very high
prices. Conus cedo - nulli,
which is found in the West
Indies, is, besides being rare,
remarkable for the variation
of its colour -markings. G.
cervus, C. adamsoni, G. thomce,
C. nobilis, and C. delesserti,
are some of the most highly
treasured, but the celebrated
C. gloria -maris, from the
Molucca and Philippine

Islands, of which only about a dozen. ^specimens are known, is still considered the
finest shell of all, and a full-grown specimen in good condition would probably now
realise about forty or fifty pounds. Some, such as G betulinus and G suratensis,
are extremely solid, but a few, G. geographies and G tulijia, are very thin. It has
been asserted that certain species have no operculum, but this is now believed to
be incorrect. This structure is small, horny, narrow, and, being much smaller than
the aperture of the shell, in no way serves the purpose of defence. A large number
of fossil species have been described from the Tertiary formations. Some instances
are on record of persons having been bitten by cones when handling them, and it
is said that the bite, to some extent, is poisonous, but -whether this character is
peculiar to a few, or common to all the species, we have no means of knowing.

The auger-shells, Terebridce, have a very different appearance to the cones, and
conchologically do not exhibit any particularly close relationship ; although the
characters of the dentition certainly indicate their approximation. The molluscs
of this family have a small head with two small cylindrical tentacles, with minute
eyes at the tips. The foot is small, rounded in front, and elongate behind, and
supports a small, oval, horny operculum, with an apical nucleus. About two
hundred and thirty species have been described. They abound in tropical regions,
but a few occur in more temperate localities, such as Japan, California, and New
Zealand. Some of the shells are so solid (Terebra mactdata), and others so
extremely elongated (T. pretiosa, etc.), that it would appear impossible for the
animals to carry them erect. Probably, in these instances, the shells are dragged
along resting upon the surface of the sand. They are all elongate in form, with

372 MOLLUSCS.

a small aperture, notched in front for the passage of the siphon. The whorls are
flat and generally divided below the suture by a spiral furrow. They are
longitudinally fluted, smooth or noduled, and it is upon these differences in
sculpture that the various subgenera are founded.

The third family — Pleurotomido3 — contains an enormous number of species,
certainly more than a thousand having been described. They are mostly small,
and show great variety in form. The species of the typical genus Pleurotoma are
spindle-shaped, that is, have a long tapering spire at one end, and a prolonged
beak or canal at the other, and the outer lip has a distinct slit somewhat below
the suture. In Surcxda and Drillia the slit or notch is at the suture, in Bela it is
indistinct. Some forms, Clavatula and Pusionella, have a semi-ovate operculum,
with the nucleus lateral ; in Pleurotoma, Drillia, etc., it is ovate-pyriform, with a
terminal nucleus ; whilst in Mangilia, Cythara, etc., it is altogether absent.
Columbarium, containing only a few species, is remarkable for the great length
of the anterior canal, and the spine-like ornamentation of the whorls. C. pago-
doides, dredged off Sydney in four hundred and ten fathoms, is one of the most
beautiful of all the family. All degrees in the length of the canal are observable,
until we find it reduced to a mere notch at the base of the aperture. Pleuroto-
midce exist in every sea, but certain groups are more characteristic of cold and
temperate climates. Bela, for instance, may be regarded as a representative
northern genus ; whereas, on the other hand, Cythara and Pusionella are tropical.
They are generally rare in individuals, although numerous in species. They occur
at all depths, from low- water mark to two thousand or more fathoms ; indeed, a
very delicate form, about an inch in length, — Clathurella monoceros, — was dredged
in mid- Atlantic, to the south-west of Sierra Leone, in two thousand five hundred
fathoms. The extinct forms of this family, occurring chiefly in the Tertiary
deposits, are perhaps as numerous as those now living.

In the family Cancellariidw the proboscis is small or rudimentary, the foot
small, the siphon very short, while the eyes are placed at the outer base of the
tentacles ; the operculum being wanting. The Cancellarias have very beautiful
shells, generally elegantly sculptured with longitudinal and spiral ridges, producing
a cancellated surface. The forms are variable ; some are oval, others turreted, and
the most remarkable of all (Cancellaria trigonostoma) has the spire drawn out
like a cork-screw. A constant feature in this family consists of three or four folds,
plaits, or plicge upon the columella. A few of the species are common, but many
are extremely rare. About a hundred different forms are known. They are
mostly tropical, but the genus Aolmete has a more northern range, extending as
far as Greenland. They are usually obtained in shallow water, but a few specimens
have been dredged at a depth of nearly seven hundred fathoms.

SECTION EHACHIGLOSSA.

This group of Pectinibranchs includes a large number of genera and species
superficially very different. They are all marine gastropods, with a well-developed
extensile proboscis, sometimes as long as, or even longer than the body. The
radula is generally long, narrow, and armed with three teeth in a transverse row,

GASTROPODS. 373

one central or rhachidian, and one lateral on each side ; the latter, however, are
wanting in certain groups. The respiratory siphon is rather long, fitting into the
anterior canal or notch of the aperture. The eggs of these molluscs are deposited in
strong leathery capsules, each capsule often containing a large number of ova. The
genus Yetus, however, which is viviparous, produces a comparatively small number
of young. All have shells, which in nearly all cases are capable of sheltering the
entire animal. The principal families in this group are the Olividce, Harpidce,
Marginellidce, Volutidce, Mitriclce, Fasciolariidce, Turbinellidce, Buccinidce,
Nassidce, Columbellidce, Muricidce, and Corolliophilidce.

The Olives (Olividce) are mostly cylindrical shells, often beautifully orna-
mented with markings of various patterns, and always having a highly glossy or
enamelled appearance. The aperture is narrow or notched in front, and the
columella is not strongly plaited as in some of the families which follow
(Marginellidce), but there
are numerous, slight,
oblique folds, some of
which pass round the base ;:%
or anterior part of the
shell, which is thus marked
off from the rest of the
surface into a distinct area. Ip
The animal has a very ^gg

large foot, capable of :;/,

covering the shell to a BLACK 0LIVE) olim maum (nat size)_

great extent, pointed

behind, and with its anterior portion (propodium) divided into two lobes. The
head is small, with pointed, slender tentacles, and the eyes about midway along
their outer sides. The mantle is produced in front into a slender appendage,
which protrudes with the breathing -siphon through the notch of the aperture ;
posteriorly it terminates in a thread-like process, which passes up the channelled
suture of the spire. There is no operculum. The olives are very active, and burrow
in the sand in search of bivalves ; and are sometimes seen in countless numbers,
the sands at low tide for miles being covered with them. Although about one
hundred and fifty to two hundred species, mostly tropical, have been described,
a few extend to more temperate seas as far north as Japan, and southward to
Patagonia. The olives are frequently used in the manufacture of shell-ornaments,
The genus Olivella differs from the typical Olivet in having neither tentacles nor
eyes, and the spire of the shell is longer and more pointed. Ancilla, another
important genus, comprises a number of polished species, which are nearly always
of a uniform white, yellow, fawn, brown, or reddish colour, and without the
markings of the olives.

The family Harpidce contains but a single genus, the well-known harp-shells
(Harpa). These are strong, broad, ventricose structures, highly coloured, and
adorned with numerous curved ribs, running parallel with the outer lip of the
aperture. The columellar margin is smooth, and covered with a thin brilliant
callus. The animal has an enormous foot, which is not wholly retractile within

374 MOLLUSCS,

the shell; and when disturbed it not unfrequently casts off the hinder part.
About ten species are recognisable. They occur in the Red Sea, many parts of
the Indian Ocean, Philippine Islands, South Sea Islands, Panama, and on the
west coast of Africa and at Ascension Island. The members of the family
Marginellidce are mostly small, some very minute, but many of them have
very beautifully coloured and highly polished shells. Nearly all are tropical, and
many of the finest and most valued are inhabitants of the West and South
African coasts. They are mostly ovoid, or subconoidal in form, with rather con-
tracted apertures, slightly notched in front ; the outer lip is involute and thickened,
and the columella has a few oblique plaits upon the lower or anterior portion.
There is no operculum ; and, as in the majority of the volutes, the radula has only a
central row of teeth. In Pseudomarginella, from Goree, on the west coast of
Africa, the shell is identical in every respect with Marginella glabella of the
same locality, but the mollusc and its operculum are said to belong to the Buccinidai.
Nearly all the species of the family Volutidai have large showy shells, and
some of them, on account of their extreme beauty and rarity, realise very high
prices. As in the Marginellidw, the columella exhibits a number of oblique folds,
but the aperture is rather more deeply notched in front for the passage of the
siphon. The form of the shell is variable; in some the spire being very short,
and scarcely rising above the last or body-whorl ; while in others (Zidona) it is
drawn out into a conical spire. The apex is sometimes (as in Yetus) enormous,
and all intermediate sizes occur until we come to Volutilithes, in which it is quite
small. This latter genus — a very common Eocene fossil of the London and Paris
basins — has very feeble columellar plaits, and is now represented by a single species
obtained in one hundred to one hundred and fifty fathoms off the Cape of Good Hope.
The animals of the volutes are large, sometimes incapable of withdrawing entirely
within the shell, and mostly without an operculum. The radula usually has only a
single row of teeth, but, in a few instances, a lateral on each side is present. The
Yetus shells are large, thin, with enormous apertures, having three or four strong,
oblique plaits on the columella. They are found on the west coast of Africa, in the
Indian and Pacific Oceans, and also off' the Philippine Islands. Y. proboscidalis is
viviparous, and produces four or five young at a time, about an inch long. The
flesh of this enormous animal is said to be eaten, after being dried in the sun, by the
natives of Senegal. As an example of the genus Voluta, we may mention the hand-
some West Indian V. musica, popularly known as the music-shell, from the colour-
markings, which resemble the lines and notes of music. It is one of the few forms
provided with a small horny operculum, and on this account has been placed in a
distinct genus (Volutolyria) by some writers. Like the rest of the true volutes,
it is oviparous. The allied genus Volutomitra, as the name implies, has affinities
both with Voluta -and Mitra; the shell and animal being for the most part
mitroid, but the tongue resembling that of the volutes. It may therefore be
regarded as a link between the two families. Three or four species are known,
one from the shores of Greenland, and two or three from Tasmania and Kerguelen
Island. The largest member of the Volutidw (Cy milium broderipi), which is
found at the Philippine Islands, sometimes attains a length of 14 inches and 30
in circumference. Rather more than a hundred species of this family are known.

GASTROPODS.

375

The gorgeously-coloured mitre-shells (Mitridce) always have been and still remain
a favourite group with collectors. Like the Marginellas, they have no operculum,
and are small in comparison with the volutes, but they equal if not surpass them
in the beauty of their colour-markings and surface sculpture. The columellar lip
is always plaited, the hinder plaits being the strongest. A remarkable feature of
the genus, at all events in some instances, is the enormous length of the proboscis,
which seems to be out of all proportion to the animal. The tongue of the mitras
has three rows of teeth, all serrated in some species, but in others, with the two
laterals simple, and of a somewhat different type. The common Mitra episcopalis,
a striking, scarlet-spotted, heavy shell, is abundant at the Philippine Islands, and
occurs in Ceylon and in Polynesia. The animal is sluggish in its movements, and
buries itself in the sand when the tide recedes. The mitras with simple lateral teeth
are mostly ornamented with longitudinal ribs or plicae, and constitute the group
Twrris. Some frequent coral-reefs, and others are found, often in considerable
numbers, crawling upon the sands in sheltered and shallow bays. Over five hundred
species of Mitridce are known. They abound in the islands of the Indian and Pacific
Oceans, and seem to be scarcer on the shores of the great continents. They are
not very numerous in the Atlantic, and even the tropical islands of the West Indies
produce but an insignificant number, of unattractive form. Mitra zonata, found
in deepish water off" Italy and in a few other parts of the Mediterranean, is a
fine species, and one of the rarest of the family. A few species of Mitridce range as
far north as Japan, and others occur at the Cape of Good Hope and New Zealand.

The tulip-shells, forming the family Fasciolariidce, are mostly fusiform (spindle-
shaped), some having very long spires and anterior canals. They never have a
thickened lip to the aperture, which is often grooved and striated within. The
typical genus Fasciolaria and also Latirus exhibit oblique folds on the columella,
a feature absent in the slender Fusus. All are furnished with a horny operculum.
The radula has three rows of serrated teeth, the central tooth being narrow, and
the laterals broad. Fasciolaria gigantea, from the coast of South Carolina, is one of
the largest gastropods, attaining a length of 2 feet. In Leucozcmia, a group of the
genus Latirus, the outer lip of the shell has a more or less prominent spine-like tooth
in front. In L. cingulata, from Panama, it is sometimes five-eighths of an inch in
length, and although it appears as if it would be a hindrance to the animal when
crawling, it doubtless serves some purpose in its economy. The allied family of
the chank-shells (Turbinellidce) is not numerous in species, but contains several
large and interesting forms. They are grouped together, on account of a similarity
in dentition. The radula has three rows of teeth, the central tooth being nearly
always three-pronged, and the laterals generally armed with a single or two
unequal cusps. The typical species of Turbinella have very solid, heavy, pear-shaped
shells, covered with a thick, fibrous periostracum, and exhibit a few strong oblique
folds on the columella. The T. scolymus, a West Indian form, is sometimes 18
inches long. In India, Turbinella is largely used in the manufacture of carved
bracelets, anklets, necklaces, and other ornaments. They are known under the
name of chank-shells, and a fishery is carried on in the Gulf of Manaar. Occa-
sionally sinistral examples are obtained, considered sacred by the Hindus, and also
valued by the Buddhist priests of Ceylon and China. In Cynodonta, another group

376 MOLLUSCS.

of Turbinellidce, the shells are compact and very strong, tuberculous or spiny,
with short spires, and the anterior canal considerably shorter than in Turbinella.
The aperture is armed with a few folds on the middle of the columella, and is closed
by a thick, and somewhat twisted operculum. The eight known species are dis-
tributed over the Red Sea, Philippine Islands, Polynesia, Pacific coast of Central
America, and the West Indies. Fidgwr and Melongena both include large striking
shells from the United States and West Indies ; and Sycotypus canalicidatus, also
from the States, is remarkable for the deeply channelled suture separating the
whorls. The egg-capsules are very curious, consisting of a long string of round
discs, about the size of a shilling, but somewhat thicker, attached to the cord by
one edge. Each capsule contains a number of eggs, and the young eat their way
out at a spot opposite the points of attachment. Semifusus colosseus is one of the
largest living gastropods, attaining a length of about 14 inches. It is an
inhabitant of the Indian Ocean, and also occurs at the Philippine Islands. Another
giant is the well-known Fusus proboscidiferus, of which the broadly fusiform shell
sometimes attains a length of 2 feet. It is found on the west and north-west coast
of Australia, and on account of the peculiar nucleus of the spire has been placed
in a separate genus, Megalatractus. The egg-capsules form a cylindrical mass
marked with a dozen longitudinal equidistant ridges, and divided off into compart-
ments, each compartment containing from twenty to thirty young. When they quit
the egg-case, they are about an inch in length, and bear no resemblance to the full-
grown shell.

The whelks form the characteristic group of the family Buccinidce, which
also includes a considerable number of other genera, and numerous species.

The animals usually have a long siphon and a large
foot, more or less square in front and somewhat pointed
behind ; the head is provided with a pair of tentacles
which support the eyes on the outside. The lingual
ribbon is well-developed, with three rows of pronged
teeth, the central with three to six cusps, the laterals
two- or three - pronged. The form of the shells is
variable ; some are fusiform, with a distinct anterior
canal, others ovate, with the canal reduced to a mere
op (a) Bucdnum undatum, (b) notch- A11 are provided with a horny operculum,
Murex erinaceus. which assumes different forms in the various genera.

Chrysodomus is essentially a northern or Arctic race,
and one of the fusiform types with a distinct siphonal canal. G. antiquus, the largest
of the British marine gastropods, was also common in the English Crags. Reversed
or sinistral specimens were the commonest form in the Red Crag. C. contrarius, found
living on the coast of Spain and Portugal, is a closely allied species. Sipho, Volu-
topsis, and Jumala are other northern fusiform groups, which have a few British
representatives. The common whelk (B. undatum) is the typical representative of
the genus Bucdnum, and is such a familiar object that a description of the shell is
needless. We may, however, direct attention to the variations existing in this species,
these being due to difference of locality, depth, etc. Specimens from deep water
have much thinner shells than shallow-water forms, and those found on some

HOW OF TEETH FROM THE EADULA

GASTROPODS.

377

parts of the Northumberland coast are remarkable for their solidity. Thousands of
bushels of this mollusc are annually consumed in London alone, and as much as
£12,000 has been realised in a year by the whelk-fishery off Whitstable. Whelks
are used as bait in the cod-fishery. The operculum of this species is roundly ovate,
formed of concentric layers, the nucleus being a little excentric. It is compara-
tively small, and of no use as a defensive door to the shell. On the coast of Kent
and Sussex a race exists, provided with two and sometimes three small opercula,
instead of one as usual. It is a peculiarity which apparently has become
permanent to some extent, but how it
originated is a matter of conjecture. The
whelk has a wide geographical range,
occurring all over the North Sea to the
Norwegian Coast, as far north as Iceland,
and on the east coast of the United States
from Cape Cod northwards. It is found
fossil in the Coralline Crag. Owing to
the variability in the shell, a considerable
number of so-called species of Buccinum
have been described ; but the total of
recognisable forms does not probably
amount to more than about sixty or
seventy. These are mostly Arctic or
northern, but a few are known from
Japan. Volutharpa is scarcely separable
from Buccinum, but the shell is thinner,
and the aperture very large. On the con-
trary, the operculum is minute, that of V.
perryi from the Japanese seas — a shell
about 2 inches long — being only about -^
of an inch in diameter. Neobuccinum is

the Antarctic representative of Buccinum ; the single known species occurring at
Kerguelen Island in the Southern Ocean. The operculum differs from that of
Buccinum in being somewhat spiral, instead of concentric, and the lingual dentition
is slightly different. Cominella, Cyllene, Tritonidea, Pisania, and Euthria are
genera referred to the family Buccinidce, on account of general similarity in the
animals, and especially of the radula. They comprise a considerable number of
species from tropical and temperate localities, but are not of sufficient interest to
be further mentioned. We may, however, call attention to the genus Euthria, as
a remarkable instance of wide geographical range. The typical species, E. cornea,
which is very common in the Mediterranean, has also been found on the coast of
the island of New Caledonia, eastward of Australia. The genus Phos contains a
small number of very beautiful species with highly ornamental cancellated sculpture.
On the other hand, the closely allied Eburna is remarkable for the smoothness
of the shell, and the spotted character of the colour-markings.

All the members of the family of dog-whelks (Nassidw) are comparatively
small, none exceeding 2 inches in length. The animal frequently has the foot —

section of whelk (nat. size).

378 MOLLUSCS,

which is large — bifurcated behind. The radula differs from that of the Buccinidce
in having the central tooth curved and finely serrated. The typical genus Nassa
comprises an extensive group of small molluscs, which exhibit a considerable
amount of variation in form and sculpture ; and upon these characters many sub-
divisions have been proposed. The shells are mostly solid, ovate or turreted,
smooth, granulated, or longitudinally ribbed. The aperture has a distinct oblique
siphonal notch, the columella is more or less coated with callus, and the outer lip is
thickened and denticulate, or grooved within. About two hundred and forty species
are recognisable, of which three are met with in Britain. The majority are found
in tropical seas. They often occur in immense numbers, and burrow in sand
and mud in search of bivalves. The operculum is often somewhat triangular, with
fine serrations along the sides. N. reticulata, the largest of the British species, is
common all round the coast. It is a great nuisance on oyster-beds, and although
exhibiting a preference for young oysters, also attacks those of more mature
growth. The egg-capsules are roundish, very compressed, and attached by a short
stalk to seaweeds. They are arranged close together in compact series, and have a
small hole at the top, through which the young escape. The subgenus Demoulia
resembles Nassa as regards the shell, but the animal (of D. retusa at all events)
has no prolongations at the posterior end of the foot. The operculum is present in
some species, wanting in others. Four of the seven known species are from West
and South Africa, and one or two are said to be Japanese. Cyclonassa, another
subgenus, agrees with the typical Nassa as regards the soft -parts, but is
characterised by a very aberrant form of shell. This is smooth, flattened, some-
what like a Nerita, and has an oblique distorted look about the aperture. C.
neritcea is a very common Mediterranean shell ; two other species being known, one
also Mediterranean, the other from the Black Sea. In the genus Bullia the animal
is very similar to that of Nassa, but the foot is larger, and the eyes are wanting.
The shells are mostly smooth, and the suture between the whorls is generally filled
up with a deposit of callus. The south of Africa may be regarded as the
metropolis of this genus, but a few species also occur on the west and east
coast, and in Mauritius, Madagascar, and Patagonia.

The dove-shells, or Columbellidw, are likewise a very numerous family as
regards species, upwards of three hundred having been described. The animal is
similar to that of the Buccinidce, but the central tooth of the radula is not armed
with cusps, and the laterals are of a peculiar type. The shells are all small, some
quite minute, and offer considerable variation in form and sculpture. Most of the
species are prettily coloured, and many occur in enormous numbers, and are
employed in the manufacture of shell-boxes and other ornaments. Columbella
abounds in the tropics, but many are found in temperate latitudes all over the
world, and two species belong to the British fauna. All are carnivorous and
mostly littoral, but some affect depths of five or six hundred fathoms.

The extensive family of the Muricidce contains some of the handsomest and
most striking forms of all the Rhachiglossa. The animals have a moderate-sized
foot, squarish in front and somewhat pointed behind ; the tentacles are slender and
pointed, supporting the eyes on the outer margin. The siphon is long, and the
retractile proboscis, containing the radula, is well developed. The latter is long and

GASTROPODS.

379

narrow, with three rows of teeth ; the central tooth having three principal cusps
or spines, and other secondary denticles, and the laterals being simple. The horny
operculum is variable, having either a lateral or terminal nucleus. The shells
exhibit much diversity of form in the different groups. Murices are carnivorous,
feeding upon other molluscs, both gastropods and bivalves. In the typical genus
Murex the animal, as it increases in size, produces at intervals beautiful foliations
or spine-bearing ridges, nearly always three or more on a whorl, which are some-
times continuous up the spire ; the siphonal canal being sometimes remarkably long
and slender, almost closed and nearly straight. In this group many of the species
are armed with numerous long spines upon the ridges ; M. tenuispina from the
Indian Ocean, Philippine Islands, and neigh-
bouring localities, being a striking example. In
the section Chicoreus the shells are strong, with
three beautifully branched ridges, and the canal
shorter than in the preceding group ; M. ramosus,
a large and abundant species from the Red Sea,
Indian Ocean, Polynesia, etc., and the beautiful
M. palma-rosce, from the Philippines, being
examples. The species of Muricantha are like
Chicoreus in form, but with numerous varices.
The west coast of Tropical America and West
Africa produce some of the largest and hand-
somest species. Of all the group, perhaps none
surpass in beauty of construction some of the
forms of Pteronotus ; M. lobbeckei, from the China
Sea, which is of a uniform delicate rose -pink
tint, and ornamented with elegant fluted frill-
like varices, being pre-eminently beautiful. There

are. several other groups, containing a number of species of considerable interest,
which cannot be further referred to in this account. Some mention, however, must
be made of the dye which can be extracted from the animals of this family.
Species of Murex and probably of Purpura — a genus referred to subsequently
— were both employed in ancient times in the manufacture of the Tyrian purple.
The dye was obtained from a white vein at the upper part of the neck of the
mollusc. When first extracted, it is of the colour and consistency of cream,
but subsequently changes, on exposure to light, to the deep purple tint. The
common British Purpura lapillus affords similar dye. Its scarcity and the
use of cochineal, and other dyes, render it valueless as a commercial product.
Murex erinaceus, the only British species, is common on oyster-beds, to which it
is destructive. All the forms yet referred to have a somewhat roundish or ovate
operculum, with the nucleus terminal or subterminal, whereas in those which
follow (Purpurinaz) it is lateral. All the members of the genus Purpura are
furnished with strong, heavy shells, suitable for protecting the inhabitants from the
rough usage of the sea upon the rocky shores they mostly inhabit. They range from
the Arctic to the Antarctic regions, the handsomest species coming from tropical
seas, The fry of several species are pelagic, and swim at the surface of the water.

animal OF Murex. b, Gill ; b', Osphradium,
or olfactory organ ; p, Purple-gland,

38o

MOLLUSCS.

EGG - CAPSULES OF

Purpura lapillus.

Like the murices, these molluscs are devourers of Bivalves. The annexed illustration
represents the egg-capsules of the common British P. lapillus. The animal and
shell of Acanthina are similar to those of Purpura, but the outer lip of the aperture
is furnished at the anterior end with a more or less prolonged conical tooth or
prong. Rapana, Concholepas, and Sistrum are other nearly-
allied forms. The members of the family Coralliophilidce
resemble the purpuras, but are characterised by the want of a
radula, and their singular mode of life, dwelling either in or upon
corals. Rhizochilus in early life is like the young of Purpura,
but subsequently it attaches itself to barked corals (Antipathes),
living a prisoner's life, immured within its own shell. It pro-
longs the lips of the shell around the stems of the coral, completely closing the
aperture, with the exception of the siphonal end, which it extends into a distinct
tube, serving to carry both water to the gill and food to the mouth. What the
nature of its nourishment may be — possibly derived from the Antipathes itself —
and what may be the reason of this self-
immurement, are problems to be solved.
Goralliophila madreporarum attaches
itself to corals ; other species live a more
active life, crawling over the surface of
the coral. Several are tinted with lilac,
and have purple apertures ; others, however,
are entirely white. Leptoconchus and
Magilus are both dwellers in coral. The
former lives in crypts excavated in brain-
stone corals, and resembles, as regards the
shell, the young state of the latter.
MagilvjS affects coral-reefs, and is remark-
able for the great alteration which takes place in the course of its career. At
first it assumes the form of an ordinary spiral shell, and takes up its abode
within the crevices of growing coral. The coral slowly advances around the shell,
and would soon enclose it, if the mollusc were not provided with some means of
defeating this. The creature prolongs the lips of its aperture into a long, but
mostly crooked tube, so as to keep pace with the growth of the coral, and keep
the tube open for the free ingress of the water. As the tube increases it becomes
too long for the animal ; consequently the mollusc fills up the spiral portion, and
as much of the tube as is not required. These shells are found in the Red Sea,
and the Indian and Pacific Oceans.

Rhizochilus antipathum. a, Young ; b, Adult.

SECTION T^ENIOGLOSSA.

The majority of the molluscs included in this section of Pectinibranchs are
marine forms ; although a few families are found in fresh water, while others are
terrestrial and air-breathers. Typically, the radula has seven rows of teeth, one
central, and three laterals on each side ; but there are a few families in which this
armature is modified. Sometimes there is only a single lateral on each side ; but,

GASTROPODS.

381

on the contrary, the number of laterals occasionally reaches five a side. They
are curved and claw -like in some groups, but in others merely have serrated
edges. Forty-two families are included in this section ; but the limits of this
work admit only of an account of some of the more important. The animals of
one group are provided with shells, which either have a distinct, prolonged
anterior canal, or else the aperture is more or less deeply notched at the base. In
another group the mouth is entire, without notch or siphonal canal. Some have a
retractile proboscis, like murices and whelks; others have a longer or shorter
muzzle or rostrum, which is somewhat contractile.

The first family is that of the tritons (Tritonidce), many of which possess large,
handsome shells, exhibiting strengthening ridges (or former lips) at intervals upon
the spire. The animal has a shortish foot, a large head projecting between the
slender, pointed tentacles, supporting the eyes at the sides or at the base, and a
horny operculum. Triton and Ranella are the two genera constituting this
family. In the former, the large T tritonis, the war-trumpet of the South-Sea
islanders, is the typical kind. It attains more than a foot in length ; and when
the top of the spire is broken or ground off, a booming note can be produced.
A similar species (T. nodiferus) lives in the Mediterranean, and was employed in
the same way by the Komans. Most of the tritons are covered with a conspicuous
periostracum, and in some cases this is beset with short hairs or bristles. The form
of the shells is very variable in the different subgenera, but all exhibit the
character of periodic ridges. The shells in the genus Ranella are very like Triton ;
but the typical forms possess a posterior canal or sinus at the upper part of the
aperture, which is not met with in the latter. The varices are mostly in two
continuous series, one up each side of the spire. The species of this and the
preceding genus are not very numerous — hardly two hundred altogether — and are
chiefly inhabitants of warm climates. A few range as far north as Alaska and
Japan ; others occur on the shores of Patagonia, the Cape of Good Hope, Amsterdam
Island, and New Zea-
land. Two species —
T. nodiferus and T.
cutaceus — have been
occasionally obtained
from the Channel
Islands. Like Strom-
bus, this group of
molluscs appear to
be great scavengers.
M. Velain, when at
Amsterdam Island,
observed that the
dead carcases of seals,
left by fishermen on
the rocks at low
water, were literally covered with lobsters and Ranella at the following tide. In
the helmet-shells, family Cassididw, the shells develop varices at intervals, like

helmet-shell (Cassis glaiica).

3^2

MOLLUSCS.

the tritons, but they are broader, more globose, and have shorter spires. The
aperture is more or less dentate on each side, and the siphonal canal short, and
sharply recurved. Upon the columellar side the animal deposits a strong shelly
callosity, which in some species is enormous, and unites with the outer lip above.
The animal closely resembles that of Triton; its dentition is similar, but the
opercula in this family are peculiar, having a lateral nucleus, and often being
rayed like an expanded fan. The shells of some species consist of different-
coloured layers, and are made use of for carving shell-cameos, in order that the
subject may stand out in relief upon a differently-coloured ground. This family
includes the genus Cassis and its subgenera, and the genera Morio and Lambidium.
Nearly all the species are from hot regions, but a few occur in Japan and New

tun-shell, Dolium perdiz (J- nat. size)

Zealand ; and the well-known Mediterranean Morio tyrrhenus has of late years
been dredged living in deep water off' the south-west of Ireland.

The tun-shells (Doliidce) are mostly thinnish and of globose form, sometimes
of very large size, and always spirally ribbed and grooved. They have no varices,
and are without opercula. The foot of the animal is large, and the retractile
proboscis long, and furnished with an expanded disc at the end, as in the figured
Dolium perdix. The shells of the subgenus Malea, which have the outer and inner
lips strongly dentate, form a connecting link with the Cassididce. Nearly all the
species, about fifteen in number, are tropical. Two, however, occur in the
Mediterranean, and several in Japan ; Dolium galea, which occurs off" the south
of France and other parts of the Mediterranean, has a shell 8 to 10 inches in
length, and is the largest gastropod of that region. This mollusc, as well as
various species of Cassidido3 and Tritonido3, are said to secrete sulphuric acid.

GASTROPODS.

383

The fig-shells ^Pirula) have an extensive foot, like Dolium, but the mantle is
largely lobed on each side, and reflexed upon the shell. This is of an elongate pear-
shape, with a short spire and a long canal, and has the surface transversely
striated or ridged, or more or less cancellated. There are nine recent species
belonging to this genus, which is also found fossil in the Chalk and Tertiary
deposits. The genus is included in the Doliidce.

fig-shell (Pirula ventricosa), from above and beneath (nat. size).

The cowry, or, more properly, kauri shells (Cyprceidce), are so well known
that a description is scarcely necessary. They are all formed much after the
same pattern, and are almost always coated with a brilliant enamel, caused by the
lateral lobes of the mantle being reflexed upon the shell. In the young the shells
exhibit a short spire, which in the course of growth becomes entirely or almost
concealed. Many of the shells are exceedingly beautiful, and some of the animals
are even more brilliantly coloured. The cowries have no operculum, but a large
foot, and can retract their bodies entirely within the shell, notwithstanding the
narrowness of the aperture. The shells, as is well known, are sold as ornaments,
and some of the rarer kinds are greatly prized by collectors. A small yellow
species, the money-cowry (Cyprcea moneta), abundant in some parts of the Indian
and Pacific Oceans, is used as coin in India and among the negroes of certain
parts of Africa. The orange cowry (C. aurora), one of the finest of the group,
used to be worn by the chiefs in the Friendly Islands. The cowries, of which
nearly two hundred species are known, are found most abundantly in tropical
regions, but a few stragglers occur in temperate seas. Only one small and ridged
species (C. europcea) is found on the British coasts, and about a hundred fossil
forms, chiefly Tertiary, are known. The genus Ovula is allied to Cyprasa as

;84

MOLLUSCS.

regards the general conformation of the animal, but has a somewhat different
raclula and shell. It contains several subgenera, the most important being Radius,
Ultimus, and Calpurnus, Radius volva is perhaps the most remarkable of all the
species. Many of them live parasitically upon sea-fans, the shells assuming the

MONEY-COWRIES.

same colour as the bark of the coral. Pedicularia and Erato also belong to this
family, although the shell of the former appears to possess no relationship with
its other members.

The wing-shells, or strombs (Strombidai), include some very large species,

which when young somewhat
resemble a long-spired cone. When
mature, however, the outer lip
thickens and spreads out, and upon
the edge may be developed six,
or more, claw - like appendages
(Pterocera). The aperture is notched
anteriorly for the short respiratory
siphon, and the outer lip situated
near this siphonal notch, and also
often posteriorly at its junction
with the whorl above. The general
form of the shell is shortly or
elongately fusiform, or conical. The
animals have a well - developed,
ringed, contractile proboscis, with
the mouth at the end, at the base
of which arise two enormous eye-
stalks, supporting on their inner side
the true, but very small tentacles.

wing-shell (Strmribus lentiginosus).

GASTROPODS.

385

pelican's foot (Aporrhais pes-pelecani).

The eyes are situated at the truncate ends of the long, cylindrical stalks, and,
like those of the Cephalopods, are more highly organised than in many fishes,
having a distinct crystalline lens, with a highly-coloured iris. The foot is unlike that
of ordinary gastropods, and not adapted for crawling ; being a powerful, muscular
organ, so modified as to serve the purpose
of a lever in their hopping or leaping mode
of progression. The operculum is claw-
shaped, and attached to the hinder branch
of the foot. These molluscs are great
scavengers, and feed upon decomposing
animals of any description. About sixty
species of Strombws have been described,
almost exclusively confined to tropical seas.
The beautiful pink S. gigas, of the West
Indies, is brought to Europe in immense
numbers, and, when ground to powder,
employed in the manufacture of the finer
kinds of porcelain. It is also used for
cameo -carving, and produces pink pearls.
The spider - shells (Pteroceras), with the

claw-like projections from the outer lip, have already been referred to. The beak-
shells (Rostellaria) are remarkable for the long, acuminate spire, and the prolonged,
slender, anterior rostrum. On the contrary, in Terebdlum, the last genus of this
family, there is no canal whatever, but merely a slight sinus or emargination at the
base of the outer lip. Allied to this family are the Aporrhaiidce and Struthior

lariidce, the former including some
remarkable fossil forms. Aporrhais
pespelecani is a common British
shell, occurring all round the coast,
and usually known as the pelican's
foot. In the Cerithiidce the shell
is typically elongate, and more or
less pointed, with a notch or recurved
canal at the front part of the aper-
ture, which is rather short. It is
generally solid, tubercular, or ribbed,
and has no periostracum. The
animals are very like the peri-
winkles, and are provided with a
horny operculum. They are vege-
table - feeders, very numerous in
species, and inhabit both salt and
brackish water. Whereas the
species of Cerithium are all marine, such forms as Potamides, Pyrazus, and
Cerithidea occur in brackish marshes, and at the mouths of rivers. The fossil
species of this family far exceed the recent, both in point of numbers and
vol. vi. — 25

Blillllllllil&^ii^^

worm-shell ( Vermetus lumhricalis).

386

MOLLUSCS.

size; Cerithium giganteum, an Eocene form, attaining quite a foot and a half
in length.

One of the most curious groups of gastropods is that of the worm-shells
( Vermetidce), in which the shells might be mistaken for the tubes of marine
worms, as they are similarly twisted and attached to stones and other substances
in the same way. They are free and spiral in early life, and crawl about like
ordinary gastropods, but they afterwards settle down and become stationary for
the rest of their existence. In these circumstances, a walking-foot, being of no
further use, becomes modified into a mere support of the operculum. The animals
are worm-like, with a short proboscis, horny jaws, and radula, and the head
supporting two short tentacles, with the eyes at the base. The species are not
numerous, and occur chiefly in warm and temperate seas. The members of the
extensive family of the Melaniidce are inhabitants of fresh water, and are
abundant in all subtropical parts of the globe. The shells are not, as a rule,
attractive, being clothed with a dark or olivaceous periostracum. Some are long,
slender, and acute, others quite globular. Perhaps the most remarkable form is
Tiphobia horei, an inhabitant of Lake Tanganyika, in Central Africa. In the
typical Melania the aperture of the shell is entire, but in some of the other genera,
such as Melanopsis and Fawnus, it is distinctly notched in front. The animal is
provided with a horny operculum, and many are viviparous. Hundreds of species
have been described, but many, as is the case in all fresh- water groups, are
distinguished by very slight differences. The Strepomatidw, or Pleuroceridce, are
the North American representatives of the Melaniidce of the Eastern Hemisphere,
from which they are distinguished by the absence of the marginal mantle-fringes,
and in being oviparous in their mode of reproduction. In certain places they
abound in such countless numbers as almost to cover the bed of some of the
streams in Tennessee and Alabama. About five hundred forms have been recognised.
The genus lo contains the largest and most striking species of all. They are
short, spindle-shaped shells, often with nodose or spinose whorls, and with the
aperture prolonged into a distinct anterior canal. They are restricted to certain
parts of Virginia and Tennessee. The little sea-snails known as periwinkles
(Littorinidce) are dwellers on the shore. They are all vegetarians, and occur in

the Arctic and Antarctic regions, as well as in
temperate and tropical shores, wherever they
can find rocks and stones to crawl upon. Some
occur at low water ; others live at high-water
mark, or where they are only occasionally
reached by spring tides. Some ascend the
mangrove trees, and have been found hundreds
of yards from the sea. Four species of
Littorina inhabit the English coast, the
commonest being the well-known L. littorea,
which is consumed in such enormous quan-
tities. The periwinkles have horny jaws, and
a very long radula, sometimes two or three times as long as the animal itself ; and
they are all furnished with a horny operculum to protect themselves with, when

spawn of periwinkle (magnified).

GASTROPODS.

387

retracted within their shells. The spawn of this species is illustrated in the figure.
Nearly allied to the last is the genus Lacuna, in which the animal has long,
slender tentacles, while on the upper part of the foot there are two long
appendages, which extend much beyond its pointed extremity. The species
illustrated occurs on the British coasts, and, like the periwinkles, feeds upon
seaweeds. The so-called staircase-shells (Solariidw) are all formed much upon

horned winkle, Lacuna divaricata (enlarged).

one and the same plan. They are more or less conical, flattened, and umbilicated
beneath, and nearly always beautifully sculptured. In Solarium the umbilicus
is often very wide, and is bordered by a crenulated edge, winding upwards to the
apex of the shell, and terminating in a notch upon the aperture. The embryonic
shell is sinistral, and in the course of growth becomes turned spire-downwards,
and, with the exception of its base, concealed by the succeeding whorls. About
twenty species are known, and are chiefly met with in tropical seas. In Torinia
the shells are more narrowly umbilicated, and not carinate at the margin like
Solariium, and the operculum is very remarkable, being conical,
and consisting of many whorls.

All the molluscs belonging to the Rissoidai are very small. The
shells are something like a minute Littorina, but they are often longi-
tudinally ribbed, a style of sculpture not met with in the periwinkles.
They are found everywhere, and live upon algae. A large number
of species have been described, and doubtless many forms from all
parts of the world remain to be discovered. Even upon the English
shores between twenty and thirty forms are met with. This family
has been divided into a number of genera and subgenera, partly on
differences in the soft -parts, and partly upon conchological grounds. The
Hydrobiidai are closely allied to the Rissoidai, and may be regarded as their
representatives in fresh and brackish water. Like the periwinkles, although

Rissoa,

388

MOLLUSCS.

furnished with gills, they are more or less amphibious, passing part of their time
out of the water. Four are British.

The viviparous pond-snails ( Viviparidai) in general appearance are not unlike
periwinkles, having a longish contractile rostrum and elongate pointed tentacles
with the eyes situated upon short projections at the base. There are two neck-
lappets, the right forming a rudimentary respiratory siphon. The foot is broad
in front and narrowed behind. The species of Vivipara, as their name implies,
are viviparous, and the young are brought forth provided with a shell having
three rows of bristles, and at once start upon an independent career, like the
adult. They are sluggish creatures, and generally live more or less in mud at the

viviparous pond-snails, Vivipara ; male on left, female on right, young (magnified) in front.

bottom of rivers or canals, and feed upon decaying vegetable or animal matter.
The North American species form the genera Melantho and Tylotoma,
and most have more solid shells than in Vivipara. One of the finest species
occurs in Lake Tanganyika, and is remarkable on account of the aperture
being somewhat effuse at the base, and in having the outer lip slightly sinuated
in the middle. On this account it was at one time placed in the separate genus
Neoihauma, but examination has shown that it does not essentially differ from
Vivipara. The character of the lingual teeth in this family is shown in the
accompanying figure representing a single transverse series. Two species occur
in England, one of which ( V. contecta) is here figured. The Valvatidaz comprise
a few small molluscs closely allied to the last. They occur in Europe and North
America, and are remarkable for protruding a plume-like gill beyond the mouth of
the shell, which is somewhat discoid or turbinate in form, Valvata cristata and V.

GASTROPODS.

389

kN*\J"«^k

ROW OF TEETH FROM THE RADULA OF Vivipara

(greatly magnified).

piscinalis occur in places throughout the British Isles. The shells of the
Ampullariidce are not unlike those of the Viviparidce, but are mostly larger, and
rather more globose. They are covered with a shiny, greenish, or olive
periostracum, and often ornamented with transverse colour - bands. All are
provided with large ovate opercula of concentric growth, which in species from
the Western Hemisphere are thin and horny, whereas in the Old World forms
they are thickened internally with a shelly
layer. Although these shells have entire
mouths (holostomatous), without a canal or
even a notch in the aperture, the animal is
provided with a long respiratory siphon.
The species of Ampullaria are amphibious,
and inhabit marshes in tropical countries.
They are provided with both lungs and
gills, and breathe both air and water.
Professor Semper observes that these molluscs " breathe not only with both gills and
lungs, but they do so in regular alternation ; for a certain time they inhale air at the
surface of the water, forming a hollow elongated tube by incurving the margin of
the mantle, so that the hollow surface is closed against the water and open only at
the top. When they have thus sucked in a sufficient quantity of air, they reverse
the margin of the mantle, opening the tube, into which the water streams."
They are capable of living out of the water for a long time, and it has been
stated that some specimens kept in Calcutta for five years were alive at the end
of that period. South America produces the largest forms, but there are also a
few handsome species from Central Africa, Madagascar, India, and the Eastern
Archipelago. In the genus Lanistes, which occurs only in Africa, the shells are
all sinistral, and have horny opercula.

The families Cyclophoridce and Cyclostomatidce comprise a large number of
air-breathing land-snails, formerly classed with the Pulmonata. The breathing-
organ is not a true lung, like that of the snails and slugs, but a vascular branchial
chamber, modified for air-breathing, and open in front, the mantle being free
above the nape of the neck. The animals are unisexual, and formed much after
the fashion of periwinkles. They have a long rostrum, two contractile tentacles,
with the eyes at the base, and the radula has seven rows of teeth, arranged as in
Littorina and allied genera. Another distinguishing feature is the presence of
an operculum, which is possessed by all the species. In the Cyclophoridce this is
generally horny, circular, and multispiral, with a central nucleus, whereas in the
Cyclostomatidce it is mostly of a shelly texture, and paucispiral. In the latter
family the animals have the sole of the foot divided down the middle by a groove,
and, when walking, the halves are alternately advanced. The species of these
families are numerous, and are principally found in hot climates. A few, however,
occur in more temperate regions ; two, belonging to distinct genera, being found in
Britain. The shells are variable in form, and can only be appreciated by studying
a series of specimens or figures. The species are classified in a large number of
genera, which, although based on a combination of characters, are mostly dis-
tinguishable by differences in the opercula. Cyclostcnna, Oto/poma, Chondropoma,

390 MOLLUSCS.

Choanopoma, Cistula, Tudora, Omphalotropis, are the principal forms of Cyclo-
stomatidai. Some of the handsomest and largest species are found in Madagascar
and Mauritius, but some of the West Indian islands are noted for the immense
number of species they produce. Among the Cyclophoridce, the most important
groups are Cyclophorus, Leptopoma, Cyathopoma, Pterocyclus, Opisthoporus
Pupina, Cataulus, and Megalomastoma. The minute forms, known as Opistho-
stoma are, perhaps, among the most wonderful structures of the whole family.

The species comprised in the family Truncatellidce are all small, and live either
between tide-marks (Truncatella) or upon the land (Geomelania). The shells are
elongate, and in the young state terminate in a pointed spire, which is subse-
quently cast off", the shells then assuming a truncate appearance at the top. They
have a very peculiar mode of progression, resembling that of the looper cater-
pillars, the end of the muzzle and the foot being successively advanced. The
characteristic feature of the typical genus (Hipponyx) of the allied family
Hipponychidce is the secretion by the foot of the animal of a shelly plate, which
is attached by its outer surface to stones, shells, or other substances. It forms a
permanent resting-place for the conical shell, and is attached to the adductor
muscle of the animal. In some of the fossil species these lower plates are so greatly
developed that they were at one time regarded as bivalved shells. Amalthea has
a shell very like Hipponyx ; it does not form a basal plate, but excavates a hole
in the surface of other shells to fit the aperture of its own.

The members of the family Calyptrceidce are limpet-like in their mode of
life, living attached to stones, shells, etc. The shells are more or less conical, but
spiral towards the apex. The interior is either simple, as in Capulus, parted off
by a transverse septum (Crepidula), or a cup-like process, varying in form, is
developed in the upper part (Crucibulum). The animals have a short proboscis,
two slender tentacles with the eyes near the base, and the mouth furnished with
a radula bearing a prolonged tusk, like the Naticidce. Being permanently located,
it becomes a matter of conjecture what they feed upon. Possibly the minute
forms of life which abound in the sea form their staple nourishment. The various
genera are for the most part recognisable by differences in the shell, the form
of the internal septum and " cup " furnishing good characters. The number of
living forms is considerable, and they are found in all seas. Two occur on the
British coast, — Calyptraia chinensis and Capulus hungaricus, — and a third,
Crepidula fornicata, supposed to have been imported with American oysters, is
becoming an established resident on the Essex coast. Closely allied to Capulus
is Thyca crystallina, which lives parasitic upon star-fish at Mauritius and in
other parts of the Indian Ocean. In the family Xenophoridm are contained a
remarkable group of molluscs known as carrier-shells, so-called from the instinctive
habit some of them possess of carrying about with them shells, stones, and other
substances, which they cement to the exterior of their own trochiform shells.
Doubtless this concealment is to some extent protective. The animals bear some
resemblance to Strombus, but their eyes are very inferior, and placed at the base
of the tentacles. They are furnished with opercula, which, however, are more
like those of Purpura than Strombus. They resemble the latter in their leaping
and scrambling mode of progression, not gliding along on the sole of the foot

GASTROPODS.

391

starfish with Thyca ; a, Shell of latter enlarged.

like most other gastropods. In the family of the naticas (Naticidcu), which is

numerous in both recent and fossil species, the shells are more or less globular

or ear-shaped, and the

animals remarkable for

the enormous develop-
ment of the foot, which

is used as a plough to

drive through the sand

in search of other mol-
luscs— mostly bivalves

— upon which they

feed. The foot is so

large as almost to

conceal the shell, and

the front part of it

(the propodium) hides

the head, which has no

visible eyes. The

shells are quite closed

in some of the groups

by a paucispiral operculum, which is either horny or shelly. Naticas are found in

all parts of the globe. The largest living species {Lunatia heros) occurs on the

eastern coast of North America, but some
\ ? of the more highly -coloured forms are

found in tropical seas. About half a
dozen species occur in Britain. The
spawn -cases are curious objects, resem-
bling a broad sandy strap coiled round
like a horseshoe.

SECTION PTENOGLOSSA.

In this unimportant group of Pectini-
branchs — which includes only the families
Ianthinidce and Scalariidce — the radula
consists of numerous rows of pointed
teeth, arranged in cross series forming an
angle in the middle. There is no central
or rhachidian tooth. The violet sea-snails
(lanthinidce) have thin trochiform shells,
adapted for a pelagic life. These are
mostly of a violet colour, the base or
underside, which is turned upwards and
exposed to the light when the animal is
swimming at the surface of the sea, being
more deeply tinted than the rest of the

violet sea-snail (Ianthina) WITH its float.

b, A bubble, drawn, somewhat too large, about to be
joined to the anterior end of the float ; c, Shell ;
I, Float ; p, Foot ; t, Head.

392 MOLLUSCS,

» shell. The most interesting feature in connection with these oceanic snails is the
curious float which they construct to support their egg-capsules. It is a sort of
gelatinous raft, enclosing air- bubbles which cause it to float at the surface ; and is
attached to the foot, the egg-capsules being suspended from its under surface. The
violet-snails feed on various kinds of jelly-fish, and occur in shoals on the high seas.
Being unable to sink, so long as they are in connection with their floats, they thus
escape from storms and are often cast ashore in immense numbers. The species
are few, and, like other pelagic forms, are widely distributed. Recluzia, the only
other genus in the family, has a pale brownish shell with a longer spire than
lanthina. It likewise forms a raft. The shells of the wentle-traps (Scalariidce)
are mostly white, and formed on the same plan. The spire is more or less
elevated, the aperture entire, and the whorls are ornamented with a succession
of ribs or varices which give the shells a pretty appearance. The animals are
carnivorous. More than one hundred and fifty species are known, and they occur
in all seas, as far north as Greenland. Four inhabit the British shores, one
(Scalaria communis) being the most prettily coloured shell of the genus. S.
pretiosa, a native of the China Seas, is the largest member. It was formerly
of value, between twenty and thirty pounds having been given for a specimen.

SECTION GYMNOGLOSSA.

This, the last of the five sections into which the Pectinibranchs are divided,
is characterised by the absence of the radula. Two families are included in it,
namely, the Eulimidce and Pyramidellidce. The former have white, polished,
pointed shells, with an ovate aperture, closed by a thin, horny operculum. Many
of them are curved in the course of growth. Some are known to live commensally
or parasitically upon or within various species of holothurians. Stylifer, which
lives in or upon star-fish and sea-urchins, usually has a thinner and more glassy
shell than Eulima, and has no operculum. A few species are found in Britain,
but the family is more numerous in warmer latitudes. In the second family the
majority of the species are very small ; and while all are dextral in the adult state,
the young shells are remarkable for having the nuclear whorls sinistral. Some are
longitudinally plicate, others transversely ridged, cancellated, or smooth, and the
columella often exhibits one or more plaits or denticles, which are conspicuous in
some and almost obsolete in others. The diversity of form and surface ornamenta-
tion, in the very numerous species of this and many other families, can only be
seen in a collection of specimens, or a good series of illustrations. About forty
species are British, none of which belong to the typical Pyramidella.

Suborder Heteropoda.

This group is regarded by some systematists as a distinct order, and by others
merely as a division of the Pectinibranchia ; and it sometimes appears under the
name of Nucleobranchiata. It includes gastropods modified for a pelagic life.
The foot, in place of being adapted for crawling, is laterally compressed, and serves
the purpose of a fin, and is also used as a means of attachment to the prey or any
floating substances. The Heteropods are found on the high seas in every warm
part of the globe. They have distinct sexes, are predatory in their habits, feeding

GASTROPODS.

393

upon all sorts of pelagic life which surrounds them. They have no jaws, but are
furnished with a radula witli seven rows of teeth like the tamioglossate gastropods.
Some have shells capable of containing the retracted animal ; in others, the shell

■

a pelagic heteroi'OD, Pterotrachea (nat. size).

394

MOLLUSCS.

only serves the purpose of protecting the vital organs, and in some forms it is
altogether wanting. The Heteropods may be divided into two families. Ptero-
tracheidce and Atlantidce. The former includes the genera Pterotrachea,
Firoloida, Cardiapoda, Carinaria, and Pterosoma ; a species of the typical genus
being shown on the preceding page. It is a transparent gelatinous creature. The
gills are exposed near the tail, and the fin-like foot, with the minute sucker upon
the edge, is seen on the opposite side. The sucker is smaller in the females than
the males. About sixteen species are more or less determinable. Firoloida
has no gill and the visceral nucleus is situated at the posterior end of
the body, with scarcely any caudal prolongation beyond it. The males are
provided with two slender tentacles in front of the eyes, the females being without

these appendages, and the fin -sucker,
as in Pterotrachea, is also larger in
the males. Neither this genus nor
the preceding has any shell. In the
allied Cardiapoda the nucleus is
pedunculated, and partly protected
by a minute glassy spiral, shell. The
most interesting of this family is
Carinaria, on account of its beauti-
ful vitreous cap-shaped shell ; the
animal being rather like that of
Cardiopoda. The commonest species
is the well-known Mediterranean
C. lamarcki, but the largest is C.
cristata from the Indian and China
seas. The embryonic shell of
Carinaria is spirally coiled like a
snail-shell, and bears no resemblance
to the beautiful adult structure. The
latter at one time was so rare that
one hundred pounds is said to have
been given for a specimen. Even
The Atlantido3 contains two genera,
Atlanta and Oxy gyrus. The shells are small, compressed, and spirally coiled, of a
glassy texture, and capable of containing the animal. The gills are situated in a
dorsal cavity of the mantle, and the foot is trilobed, one portion of it supporting
a minute, subtrigonal operculum. About twenty species are recognisable,
Oxy gyrus being represented by only two. They abound in the warmer parts
of the Atlantic, Indian, and Pacific Oceans.

Suborder Scutibranchiata.

The great feature of these animals is the absence of certain functional
organs in the different sexes ; the radula being also of a peculiar type, and armed
with several central and lateral teeth. The two sections of the suborder,
Rhipidoglossa and Docoglossa, are based upon differences in the radula. In the

Atlanta peroni (magnified).

now, large and perfect shells are rare.

GASTROPODS.

395

FRESHWATER NERITE,

former there are nearly always several central teeth, one lateral and many small
marginals ; and in the latter the typical radula, which is very long, has one or two
pairs of central teeth, a large single lateral on each side, with a few small
marginals. The first family (Helicenidce) forms a numerous group of small
operculated land-shells, which abound in the West Indies and the islands of the
Pacific and Indian Oceans. A few occur in Australia, China, and Central and
South America, but they are unknown in Europe or Africa. Many are attractively
coloured, and a few remarkable for the serrate keel at the periphery. Next come
the nerites {Neritidm), all of which are aquatic, and feed upon vegetable substances.
In Nerita the shells are globular, and strongly made to resist the action of the
waves, for these molluscs are inhabitants of the seashore. They are furnished
with a shelly operculum, which has a process jutting out from beneath and fitting
under the toothed or wrinkled columellar lip when the mollusc retires within its
shell. The species of Neritina have mostly thinner shells,
especially those which inhabit fresh-water streams, and are also
furnished with an operculum, like Nerita, but thinner. The
pillar-lip is thin and smooth, or only finely dentate at the edge.
In the section Clithon the shells are beset with a coronet of Neritina (nat. size).
spines. The most remarkable form of that group is N. Icmgi-
spina, from mountain streams in the Mauritius. About two hundred species of
Neritina are known, which abound in intertropical regions and the islands of the
Pacific. One small species, JV. fiuviatilis, occurs in Britain, where it is found in slow
rivers with a stony or gravelly bottom, and is often coated with a calcareous deposit.
The animal has a stout proboscis, long, pointed tentacles, and eyes placed upon short
stumps at the base of the tentacles. The species of Septaria are somewhat limpet-
like, but with the apex of the shell bent towards one end. They also have an
operculum of a peculiar type, partly embedded in the foot. The species are prin-
cipally met with in tropical islands. Among the fossil forms, Velates conoideus is
interesting on account of its exceptional mode of growth. The top-shells (Turbinidai),
like those of the next family, have one characteristic in common, namely, a bril-
liantly pearly layer beneath the outer calcareous surface. The animals of both
groups are vegetable-feeders and much alike, and are peculiar on account of the
tentacular processes on the sides of the foot. In the Trochidw the operculum is
horny, circular, multispiral, and with a central nucleus ; in the Turbinidai, it is
thickened with an outer shelly layer, consists of fewer whorls, and often has the
nucleus excentric. The latter family is typified by the genus Turbo, which has been
divided into a number of groups or subgenera on account of differences in this
structure. The species are fairly numerous in tropical seas, but rare in more tem-
perate regions. Of the allied genus Phasianella only one species (P. pullus) reaches
the British shores. The Trochidce have a wider range, are far more numerous, and
occur everywhere from the Arctic to the Antarctic circles. The beauty of sculpture
and coloration of many of the species of the typical genus Trochus is beyond descrip-
tion, and can only be appreciated by an examination of the shells themselves. Most
forms are littoral, or inhabitants of shallow water, but a few, and these among the
most beautiful, have been dredged at enormous depths. Nearly twenty different
species occur around the British coast, and some of them are extremely elegant in

396

MOLLUSCS,

form and structure. The family Delphinulidce in many respects resembles the
Trochidce, and is represented only by the single tropical genus Delphinula. The
ormers {Haliotidce), although few in number, form an important family, on account
of the economic value of the beautiful pearly shells which are employed in inlaying.
They are ear-shaped, depressed, with a very small spire, and the last whorl, which
practically contains the entire animal, correspondingly large, and pierced with a
series of holes commencing at the spire and extending to the front margin, in a
line subparallel with the left side. The outer surface is calcareous, and often
beautifully sculptured and coloured, but the interior is lined with the most
brilliant pearl. The holes in the shell admit water to the gills through a slit in

the mantle beneath, and on the edges
of the slit there are three tentacular
processes which the animal passes
through certain perforations. Hal-
iotis, like the limpets, has a large foot,
adapted for adhering to rocks. Some
of the larger forms hold on with such
tenacity, that it is impossible to
remove them without damaging the
shells, except with the aid of hot
water. The genus is most abundantly
represented in Japan, California, and
Australia ; but is also met with in
New Zealand, the Philippine Islands,
Oceania, some parts of the Indian Ocean, and round the African coast, while
one species (H. tuberculata) ranges as far north as the Channel Islands.
They are locally known as ormers, and are consumed in considerable quantities.
When properly prepared and cooked, they make a savoury dish. It is worthy
of notice that Haliotis does not inhabit the South American coasts, nor is it
found on the Atlantic, side of North America. Until some fifty years ago,
the typical genus of the family Pleurotomariidm was supposed to be extinct.
Four recent forms are now known, one from Japan, one Moluccan, and
two West Indian. Two of these are larger than any of the extinct species.
Pleurotomaria has a trochiform, discoid, or globose shell, pearly within, with a
more or less deep slit in the outer lip of the aperture ; the latter being the
characteristic feature of the group. It has existed since the Palaeozoic epoch. In
Trochotoma, an allied genus, there is a hole behind the lip in place of the slit, and
Polytremaria exhibits a whole series of perforations. The anatomy of Pleuroto-
maria shows that it has close relationship with Haliotis. Like Trochus, it is
furnished with a horny spiral operculum. A magnificent specimen of P.
adamsoniana is exhibited in the shell-gallery at the Natural History Museum.
Sclssurella is another genus of this family, containing a number of very minute
shells with a slit in the lip like Pleurotomaria; 8. crispata being a pretty
little mollusc found in Britain. . The members of the so-called key-hole limpets
(Fissurellidai) mostly have shells like those of the limpets in form, but either
perforated at the apex, as in Fissurella, slit at the front margin (Emarginula), or

Delphinula laciniata (nat. size),

GASTROPODS.

397

with a hole between the front edge and the apex {Rimula,, Puncturella). In
Scutum the shell is less conical, and more elongate, and only very faintly sinuated
at the front margin. It is white, and almost wholly concealed beneath the mantle.
The holes and slits in these shells serve excretory purposes. The animals are
remarkable for their two symmetrical gills, and certain points in their internal
anatomy, which offer some resemblance to the bivalves. More than a hundred
species of Fissurella are known from all seas, except the Arctic. The west coast
of South America produces some of the handsomest kinds ; but the giant of the
genus, F. (Lucapina) crenulata inhabits the shores of California.

SECTION DOCOGLOSSA.

, The second group of Scutibranchs comprises the families Acmceidce, Patellidai,
and Lepetidce, all being limpet-like molluscs, with a peculiar form of dentition,
as already described. The shells of these
families are alike in construction, but the
animals differ essentially in their respira-
tory organs. In Acmcea there is a single
branchial plume, or ctenidium, over the neck ;
in Patella the gills are arranged in almost a
circle around the foot ; and in Lepeta the gill
is entirely wanting. In addition to these
differences the radula affords further distin-
guishing characters. Limpets are generally
attached to stones and rocks, but when the
tide is up they quit their resting-place in quest
of food, which consists of various kinds of
Algae. As the tide ebbs they creep home
again to the spot which each appropriates as
its own location. The common limpet is one
of the molluscs eaten on certain parts of the
British coasts. With regard to the tenacity
with which the limpet holds on, experiments
have been made showing that a force of
sixty-two lbs., or one thousand nine hundred and eighty-four times its own

weight, is required to detach it from the rock.

EDGAR A, SMITH.

UNDER SURFACE OF LIMPET.

a, Foot ; b, Mantle ; c, Gills ; d, Mouth ;
e, Tentacles.

CHAPTER XL

Molluscs, — concluded.

Chitons Tooth-Shells, and Bivalves, — Classes Amphineura,
Scaphopoda, and Pelecypoda.

The Chiton Group,— Class Amphineura.

The Molluscs included in this class may be regarded as aberrant gastropods,
differing from ordinary forms in their symmetrical conformation, having the mouth
and excretal orifice at the two extremities of the body, and the tissues of the mantle
more or less spiculose. The symmetry which characterises the external parts also
extends to the internal organisation. The group is divided into the two orders
Polyplacophora and Aplacophora ; and is regarded by some authors, and perhaps
correctly, merely as an order of Gastropoda, and not forming a distinct class.

Chitons, — Order Polyplacophora.

The well-known chitons (Chitonidce) are the only forms included in this
order, and are externally recognised by their shells consisting of eight separate

pieces or valves, as
they are termed,
which are arranged
over the back, and
connected at the sides
by the tough margin
of the mantle in
which they are
embedded. In most
cases the valves arc
close together, extend
right across the back,
and are exposed ; but
in some genera they
are far apart (Cryp-
toplax), and in others
entirely covered by the mantle (Cryptochiton). The foot occupies the entire
ventral surface of the body, and the mantle covers the upper surface, extend-
ing laterally beyond the shell. This portion is known as the girdle, and is
nearly always covered with spines, scales, or spicules, which, to some extent, are

common chiton (Ohiton squamosus).

CHITONS.

399

DIFFERENT STAGES OF THE LARVA OF CHITON (magnified).

characteristic of the different groups into which the Chitonidce have been divided.
The gills are placed on each side between the mantle and the foot, and vary in
length. Adult chitons have neither eyes in their head nor tentacles, but the
mouth is provided with a long radula, the teeth of which are arranged in a very
peculiar complicated manner. The chitons are bisexual, but, like the limpets,
destitute of certain functional organs. In the early stages the young chiton bears
no resemblance whatever to its
parent. This can be appreciated by
observing the accompanying figures
illustrating three stages in the
development of Chiton marginatus,
one of the dozen species found on
the British coasts. The embryo (A)
is a spherical body, £j of an inch in
diameter, divided into two unequal
parts, the dividing line being marked
by a row of cilia, and a tuft of similar cilia being situated at the vertex of the
smaller half. The eyes are visible upon the lower portion below the cilia. In a
later stage (B and 0) the division of the back into eight sections is remarkable
and unique in the Mollusca. At this stage the foot begins to develop, the forepart
of the animal being ciliated. In later stages of the development the eyes and cilia
disappear, the forepart shrinks up into the ridge surrounding the mouth, and the
back develops the eight shelly plates. It has already been stated that the adult
Chiton has no eyes. This is only true as regards the head of the mollusc, for
Moseley made the discovery that certain forms have the shell studded with eyes, of

which as many as eleven to twelve thou-
sand sometimes exist in a single individual.
They are not unlike those already referred
to as present on the back of Onchidium.
Chitons live principally on rocks and
under stones at low water, or at moderate
depths, but a few have been obtained as
low down as two thousand three hundred
fathoms. They are all marine, very slug-
gish in their movements, and, if disturbed
from their resting-place, roll themselves
up into a ball like a wood-louse. The
number of recent species is considerable,
and they appear to range all over the globe. Fossil remains of certain forms have
been found in most geological periods, since the Silurian.

"V"Nv

eyed chiton (ScMzocMton incisus). Anterior valve,
with six rows of eyes (enlarged).

Order Aplacophora.

The molluscs of this order are somewhat worm-like, with a mantle enclosing
the entire body, but not secreting a shell, and more or less studded with spicules.
They are related to the chitons by certain points in their anatomy, especially with

400 MOLLUSCS.

regard to the disposition of the nervous system. The respiratory organs, when
present, are terminal and placed within the anal cloaca. In most of the forms the
foot is reduced to a mere longitudinal groove, and does not appear adapted for
a locomotive organ. The number of known species is limited. They occur at
moderate to abyssal depths in the Arctic and Atlantic Oceans, from the Barents Sea
to the coast of Spain. Two families constitute this order, namely, Chwtodermat-
idce and Neomeniidce. The former contains but a single genus, Chcetoderma. This
degraded mollusc, at one time placed among the Gephyrean worms, has an elongate
worm-like form, with an inflation at both ends. The mouth is terminal, and armed
with only a single tooth— a poor representative of the molluscan radula. The pedal
groove is wanting, and the sexes are separate. The only known species — about an
inch in length— occurs un&er stones on the shores of Norway, but has also been
dredged in deep water off the coast. The Neomeniidce comprise the genera
Ncomenia, Proneomenia, Lepidomenia, Ismenia, Paramenia, and Dondersia.
Neomenia, which has been found off the west of Scotland, ranges from Scandinavia
to the Mediterranean, and is the best known. N. carinata is about an inch long,
rather compressed laterally, curved longitudinally, with the back keeled and the
ventral side with a narrow foot-groove, extending the greater part of its length.
The mouth is unarmed with a radula, and the sexes are united in each individual.

The Tooth-Shells, — Class Scaphopoda.

Everybody knows the tooth-shells, resembling in miniature the elephant's
tusks, and often found on the sandy shores of England. They are scientifically
known as Dentaliidce, and in former times were associated with the marine worms,
their shells bearing a strong resemblance to the tubes of certain annelids. They
are more or less elongate, nearly always slightly curved, and are bisexual. The
head is rudimentary, and in this respect the scaphopods resemble the bivalves.
They have no tentacles, eyes, or heart, and the organs of respiration and circulation

are rudimentary. At the anterior end
of the animal is situated the foot,
which is not a creeping disc, but
adapted, like that of some bivalves,
for burrowing in sand and mud, in
which they live and obtain their food,
common tooth-shell, Dentalium vulgare (nat. size). consisting of diatoms and f oraminifera.

They are said to capture these minute
organisms by means of a number of long contractile filaments with expanded
extremities (tentacula or captacula) which are situated near the mouth, which is
armed with a radula, and surrounded by labial palpi. The shell is cylindrical,
usually somewhat tapering posteriorly, open at both ends, and generally white. A
few species, however, are of a greenish tint, and others are pinkish. They are
smooth, longitudinally striated and ridged, mostly circular in section, but a few are
angular, compressed, and otherwise irregular as regards form. Some are simple at
the narrow end; but others exhibit a more or less elongate notch or slit on the
ventral or convex side. In some species of Dentalium the end has several notches,

BIVALVES.

401

and in Schizodentalium a series of holes takes the place of a ventral slit. Fossil
tooth-shells are numerous from the Devonian epoch upwards, but are most abundant
in the" Tertiaries. The living forms, of which about a
hundred have been described, occur in all parts of the globe,
and have been dredged at the greatest depths, although
they are probably most abundant in a few fathoms.

The Bivalves, — Class Pelecypoda.

This great division includes all forms which secrete a

bivalved shell, like the oyster, cockle, and mussel. The

Pelecypods offer a different type of organisation from that

prevailing in the other classes. The absence of a head, and

the bilateral symmetry of the animal, enclosed within a

bivalved shell, are characteristic of the class. The mantle

is divided into two similar lobes (g), right and left, forming

a flap on either side of the body, to which it is connected

at the upper part beneath the hinge-line of the shell. It is

usually very thin, excepting at the edges, which are some-
times double or even threefold. In some genera the edges

of the two lobes are free or unconnected at any point

excepting at the dorsal attachment, in others they are joined

in one or more places, leaving orifices for the protrusion of

the foot (a) in front, and for the entrance of the water to

the gills (d, e), and for the extrusion of waste and other

matter at the posterior end (/). The mantle at this posterior opening is often

considerably produced, forming one or two
a\ 6 distinct tubes or siphons (h), which vary

considerably in length in different groups,
equalling in some instances several times
the length of the shell. The extreme
development of these siphons obtains in
Teredo, where they constitute the principal
mass of the animal. Some pelecypods
appear to be all foot, this member being
enormously developed in the razor -shells
(Solen), for example. In others it assumes
smaller dimensions, or it may be absent,
as in the oyster. It is used either as a
means of locomotion, or for burrowing in
sand or mud, or perforating rocks, wood,
and other substances; its form conse-
quently being very variable. The mouth
(6) is situated at the anterior end of the
body, at the upper front part of the foot,
forming a simple transverse aperture. The

SECTION OF ANIMAL OF

Dentalium (enlarged).

a, Front mantle - cavity ; d,
Hinder mantle- cavity ;
b, Mouth process ; c,
Anal opening ; d, Foot-
cavity ; e, Tentacle sup-
ports ; /, Posterior end.

'■*>.•;

y

i

SOFT-PARTS OF RIVER-MUSSEL (Anodoilta).
VOL. VI. — .26

402

MOLLUSCS.

lips, upper and lower, are usually prolonged on each side into two lobes (c), or labial
palpi. These vary in form, but are mostly triangular. In some groups they are
very large (Tellinidce), but in others they are practically wanting. The mouth is
not armed with jaws or radula, for in creatures which never prey upon other
animals, or go about seeking their food, such structures would be useless. Bivalves
obtain their food — consisting of microscopic organisms — in the course of respiration.
Whatever is carried in by the inflowing current is collected on the gills, and then
conveyed by the palpi to the mouth. The leaf-like gills (d, e) are arranged on
each side of the body, and enclosed by the mantle. Each gill is partly attached
by its upper or dorsal margin. This gives rise to two rows of hollow filaments,
which are in a few cases simple and disposed in opposite directions, but are
generally parallel with one another and directed towards the ventral side, with the
filaments long and refolded upon themselves, so that each row forms a double
lamella. These filaments are united one to another by cilia. The gills and the

inner surface of the mantle - cavity are
covered with microscopic cilia, which through
their vibratile motion produce the currents
of water necessary for respiration. The
water generally flows into the pallial cavity
at the posterior ventral side, and there is
filtered through the gills, passing out again
posteriorly through the anal opening. The
nervous system consists of three pairs of
ganglia, a cerebral or supraoesophageal, a
pedal, and a visceral pair. The cerebral
ganglia (1) are mostly placed above the
oesophagus, the pedal pair (2), as their name
implies, within the foot, and the last pair
(3) are situated in front of or just beneath
the posterior adductor muscle.

Most pelecypods are endowed with the
senses of touch, smell, and hearing, and some
are provided with eyes. These are found
either upon the edges of the mantle or at
the end of the siphons ; and in some forms,
such as Spondylus and Pecten, they are highly developed. The sexes are generally
distinct, but occasionally united. The young are produced from eggs, which are
either cast free in the water, or are hatched between the branchial lamellae of the
parent. The shell, as already stated, is composed of two pieces, right and left valves,
which are protective of the soft parts, and correspond each to a lobe of the mantle.
They are generally of equal size and shape, but in certain groups they differ con-
siderably in these respects. They are nearly always joined dorsally by an elastic
ligament, or resilium, and often interlocked at the same place by projections on
the edges of the valves, termed hinge-teeth. In the majority of species the valves
shut closely together all round the edges, but in many they gape at one or both ends,
or at the ventral side. In certain species of Pinna the two valves are actually

ANATOMY OF 1UVER-MUSSEL.

BIVALVES.

4°3

united along the dorsal margin, but they are never connected on the ventral side.
Bivalves clothe their shells with a more or less distinct periostracum, which is some-
times thin, smooth, and shining, and often of a yellowish or olivaceous tint, or it
may be thick, pilose, velvety, or rugged. It has been already noticed that the
valves are nearly always connected dorsally by a ligament. This is not, however,
the means by which they are held together, or closed with such force ; this closure
being effected by one or two muscles (adductors), firmly attached to the inner
surface of the valves, and endowed with such power of contraction, that it is an
impossibility to force them apart with-
out injury. The places of attachment
of these muscles (m, m') are generally
visible, as well as other minor scars
caused by the pedal retractor muscles.
The point of attachment of the edge
of the mantle, known as the pallial
impression, is often quite distinct ; it is
parallel with the lower margin of the
valves, and, in some groups, is more or
less deeply sinuated (n) below the
posterior adductor impression. All
pelecypods are aquatic, the majority
being marine. They are less numerous
than gastropods in species, but in in-
dividuals are at present, as in past ages, relatively far more so. They are found at
all depths, from low-water mark ; many having been dredged in more than two
thousand fathoms. Bivalves, however, are most abundant in shallow water. They
live buried in the sand or mud, or attached to rocks and other substances, either by
the shells themselves, or by means of a byssus, consisting of horny fibres secreted by
a gland near the extremity of the foot. Others bore into rocks, wood, and other
substances, and a few take up their abode in the tests of certain Tunicata, and in
sponges, in the grooves of sea-urchins ; and one species {Entovalva) lives parasiti-
cally inside a sea-cucumber. Dr. Pelseneer divides the class into five orders, based
mainly upon the structure and morphology of the gills, but at the same time upon
the general conformation of the animal. To explain in detail the differentiating
anatomical characteristics of these orders would be beyond the scope of the present
work, and consequently only salient features can be mentioned.

left valve OF Meretrix.
Anterior ; b, Posterior end ; c, Umbo :
margin ; m', Anterior adductor scar ; m
n, Pallial sinus.

d, Ventral
Posterior ;

Order Protobranchiata.

In these bivalves the gills have simple unreflexed filaments, disposed in two
rows in opposite directions; the foot being expanded, with crenulated margins,
and with scarcely any byssal gland. The families Nuculidce and Solenomyidce
constitute this order. The molluscs belonging to the former are all marine ; and
have the mantle free all round, or forming two small posterior siphons. The gills
are small, but the labial palpi very large. In the typical Nucida the shell is
small, more or less triangular, generally covered with a greenish olive periostracum

4°4

MOLLUSCS.

without a pallial sinus, and pearly within. The hinge is composed of numerous
pointed interlocking teeth on each side of the cartilage-pit beneath the umbones.
Unlike Nucula, the genus Nuculina is provided with two small adjacent siphons.
The shell is usually somewhat produced or beaked posteriorly, has a slight pallial
sinus, and is not pearly within. The hinge-teeth and the resilium are as in
Nucula. Yoldia is like Nuculina in shape, but has longer siphons, and the
periostracum more glossy. The shells of Malletia are like those of Yoldia, but the
ligament is external. Nucula and Nuculina have a world-wide distribution, and
are numerously represented in species. Yoldia and Malletia, on the contrary, have
comparatively a few representatives in Arctic, Northern, and Antarctic regions.
The fossil forms belonging to this family are far more numerous than the recent,
and include several generic groups which no longer exist. In the second family,
Solenomyidce, the animal is remarkable for its proboscis- like foot, expanded at the
end into a flattened disc with a dentate edge. The mantle is united ventrally,
but open in front for the passage of the foot, and posteriorly for the siphons. The
shell is elongate, compressedly subcylindrical, without hinge-teeth, and clothed with
a thick dark chestnut-coloured horny periostracum, which, when dry, is very
brittle. Only about six species of one genus, Solenomya, are known, but these are
widely distributed, being found in the Mediterranean, on the east coast of North
America, in Patagonia, the Indian Ocean, Australia, and New Zealand.

Order Filibranchiata.

In this group the gills are smooth and their parallel filaments are directed
ventrally, reflexed, and provided only with ciliated interfilamentary junctions ;
the foot being usually furnished with a byssal gland. In the family Anomiidai
the shells of the typical genus Anomia are generally very irregular in their growth,

inequivalve, and somewhat pearly within ;
the more convex valve being remarkable for
the large number of muscular impressions,
and the flat valve for a perforation near the
hinge. This aperture is for the passage of a
calcified byssus (n), by means of which the
mollusc attaches itself to rocks and stones.
The animal has a small foot ; the mantle is
free all round, and there is but a single
central adductor muscle (m). About forty
species are known, two of which occur in
Britain. Placuna is another genus of this
family, in which the shells are very flat, with-
out any byssal opening ; the valves being thin,
somewhat nacreous, with two long divergent
hinge-teeth to which the ligament is attached. About half a dozen species from
the Indo-Pacific Ocean are known. P. sella has a somewhat wavy or cockled
appearance, and is known as the saddle-oyster, on account of its saddle-like form.
The arks (Arcidai) are nearly all strong heavy shells, generally equivalve, but in

>m —

niGHT side op Anomia, with shell removed.

a, Opening for hinge ; m, Adductor muscle ; n,
Calcified byssus.

BIVAL VES.

4°5

somo instances more or less inequivalve ; and always remarkable for their straight
hinge-line, furnished with very numerous teeth. The form is variable ; but the
valves are generally radiately ribbed, and more or less covered with a periostracum,
which may be smooth and thin, or thick, and very rugged. They may either meet
all round when closed, or may gape ventrally for the passage of a byssus. There are
two adductors far apart, and the pallial line is simple. The species — both recent and
fossil — are very numerous ; and at the present time occur in all seas, some having a
very wide distribution. For in-
stance, the little Area lactea,
which is found on the British
coast, also occurs in the Philip-
pine Islands, the Red Sea, South
Africa, Ascension Island, and the
Mediterranean ; and another
species (A. corpulenta) has been
dredged off North Australia,
south of Amboyna, in Mid-Pacific,
and off the coast of Chili, in
depths ranging from two hundred
to two thousand four hundred
and twenty-five fathoms. In the
allied Pectuneulus the shell is
rounded, strong, equivalve, with
the hinge-teeth in a curved line ;
the outer surface being sometimes
covered with a velvety or pilose
periostracum. Limopsis some-
what resembles Pectuneulus in
form, but the shells are more com-
pressed and clothed with a fibrous
periostracum, and the animal
spins a byssus. Several of the
species have been dredged at
enormous depths in the Atlantic.
The genus Trigonia, represented
by about half a dozen species
occurring on the shores of

Australia, is all that now remains of the large family Trigoniidce, of which several
other genera, with a very large number of species, occur fossil in the Secondary
and Tertiary rocks. The valves of Trigonia are beautifully pearly within, equal,
radiately ribbed, with an external ligament, and a few strong striated divergent
hinge-teeth. The umbones are inclined posteriorly — a very unusual feature in
bivalves. The foot of the animal is large and powerful, used in crawling and
leaping, and without a byssus. In some of the Jurassic rocks of Weymouth
trigonias form a bed several feet in thickness. Mussels (family Mytilidce) are
such well-known shells that a description is unnecessary. They are found all over

common mussel [My tilus edulis), CLOSED and attached by the
byssus (nat. size).

406

MOLLUSCS.

the world ; one very large species from the shores of California sometimes reaching
fully 9 inches in length. They anchor themselves by a byssus, but also have the

power of moving from place to place, by
casting off the byssus, extending the foot
in the direction they determine to proceed,
and attaching a byssal thread, which
supports the animal while the foot is
again extended and another thread spun.
This process is repeated again and again,
and thus progress is made. The structure
of the animal may be understood by
observing the accompanying illustration,
where a represents the edge of the
mantle; b, the foot; c, the byssus; d.e,
the foot -muscles; /, the mouth; g, the
labial palpi ; h, mantle-lobe ; and i.j, the
inner and outer gill-plates. To the same
family belong the date -shells (Litho-
domus), which, as shown in the accom-
panying illustration, are stone - borers.
The shells are date-like, thin, and covered
with a yellowish or brown periostracum.
The boring is chiefly effected by the foot.
The columns of the temple of Serapis at Puteoli are perforated by a species of
these molluscs, at a point far above the present sea-level, thus showing that these

h

COMMON MUSSEL, OPENED TO SHOW THE VARIOUS

organs (nat. size).

DATE-SHELLS IN THE ROCK (nat. size

ruins must at some time have been submerged, and that the coast has changed its
level within historic times at several epochs.

BIVALVES.

407

Order Pseudolamellibranchiata.

The gills in this order are folded, and their filaments furnished with conjunc-
tive or vascular inter foliary junctions ; the mantle being free all round, and the
foot small or absent. Aviculidce, Prasinidce, Ostreidw, Pectinidce. Limidce,
Spondylidce, and Dimyidce are the families constituting this order. The first
family (Aviculidce) is of importance as including the pearl-oysters. The shells are
mostly compressed, but vary much in outline. In the typical genus A vicula the
shell is oblique with a straight hinge-line, more or less produced into wings, which

pearl-oysters (^ nat. size).

are sometimes long and slender. In the pearl-oysters, Meleagrina, there are, how-
ever, no wings, and in the case of M. margaritifera the shells become very thick
and heavy. This species is one of the principal pearl-producers, and is largely
collected by divers off the north coasts of Australia and other places, not only for
the pearls which they may contain, but also for the shells themselves, which
are valuable as mother-of-pearl. Until recently, the fishery was carried on by
native divers, but now the diving-dress is largely employed. The Ceylon pearl-
oyster, M. fucata, is much smaller than the Australian species. This fishery has
been carried on for over two thousand years, and the accumulation of shells is so
enormous as to extend for miles several feet deep. The shells are thin and of
little use as mother-of-pearl, consequently they are thrown away, after being

4o8

MOLLUSCS.

examined for pearls. Pearl-fishing is also carried on in the Persian Gulf, the
South Sea Islands, Panama, West Indies, and a few other localities. The spherical
pearls, like the shell itself, are produced by the mantle, and probably other parts of
the animal also. They consist of layers of pearl, deposited round some foreign
substance which has intruded itself within the shell. This may be a grain of
sand, but is said to be usually an egg of the mollusc itself, which has not properly
developed. The hammer-oyster (Malleus), Vulsella, Crenatula, and Melina are
other interesting existing forms of Aviculidce, and many extinct genera have
been referred to this family.

The shells of the oysters (Ostreidw) are so familiar that no description is

necessary. The animal
has no foot, and the
mantle -lobes are free
nearly all round, the
borders being fringed
with short papillae.
The shells, excepting
in the very early
stages, are closed by
a single adductor. The
sexes are separate in
the American oyster
(Ostrea virginiana),
but united in the
British 0. edulis. In
a gastronomic point of
view the oyster stands
far above all other
molluscs, and its arti-
ficial cultivation was
practised by the
ancient Romans, and
at the present time
forms a most import-
ant industry in many
parts of the globe.
The oyster is- very
prolific, a single in-
dividual of the common species having been estimated to contain over a million
embryos, whilst the American form is said to discharge ten times as many.
0. edulis is not full-grown until about five to seven years old. Oysters are
incapable of motion, and attach themselves to other shells, rocks, and other
substances by the convex or deeper valve. During May, June, and July, the
eggs are discharged into the gills, where they remain until hatched ; and it is
during this period that oysters are out of season. Oysters are cosmopolitan;
wherever there is a rocky coast, excepting in Arctic climates, they are sure to

ONE VALVE AND SOFT-PARTS OP COMMON OYSTER.

a, Position of mouth ; b, Mantle ; c, Adductor ; d, Junction of mantle-lobes ;

(Nat. size.)

Gills.

BIVALVES.

409

MARGIN OF MANTLE OF PECTEN, SHOWING TENTACLES

and eyes (somewhat magnified).

be found. They are irregular in their growth, and consequently the deter-
mination of the species is a matter of difficulty. The pectens or scallop-shells
(Pectinidce) are remarkable for the variety and beauty of their coloration and
sculpture. In most species the shells are nearly equivalve ; but in a few, of
which the common edible scollop is an example, the right valve is convex, and
the left flat. One species (Pecten
jacobceus) of the Mediterranean
was worn as a badge by pilgrims
who had been to the Holy Land.
Most of the pectens are orna-
mented with radiating ribs, but a
few are smooth. Some swim
freely by flapping their valves,
others live permanently attached
by a byssus. The animal has
the mantle free, and frequently bears a row of brightly coloured eyes on the
margin. The foot is small, the gills are extremely delicate, and the single adductor
muscle in the adult is excentric. They are generally hermaphrodite, but sometimes

the sexes are separate.
More than a hundred
species from all parts
of the world and all
depths have been
described. Ten occur
on the British coasts,
and fossil species are
numerous in all forma-
tions, from the Carboni-
ferous. The file -shells
(Limidce) somewhat
resemble the scallops,
but are nearly always
white, and the edges of
the mantle, which have
no eyes, are furnished
with long tentacular
filaments. Some swim
freely by flapping their
valves, others attach
themselves by a byssus,
or, as in the accompany-
ing figure, construct a
nest of broken shells,
stones, and other substances held together by a network of byssal threads.
The two largest species occur off the coasts of Norway and Japan. The recent
species of the chief genus (Lima) are not numerous, and some occur at

file-shell (Lima) in its nest (nat. size).

410 MOLLUSCS.^

great depths. The fossil forms, on the contrary, are more abundant, from the
Carboniferous age, and some of the species from the Lias (Plagiostoma) are of
very large size. The members of the allied family Spondylitica are known
popularly as thorny-oysters, on account of the spiny character of their surface-
ornamentation. In general shape they are rather like the pectens, and similarly
brilliantly coloured ; but they have much more solid shells, and the hinge consists
of powerful interlocking teeth, while the animal has no byssus, a more rudi-
mentary foot, and lives, with a few exceptions, attached by one of the valves to
rocks and stones. The ligament of Spondylus is internal. The single adductor
muscle is a little excentric, and the mantle-margin has a row of eyes.

Order EULAMELLIBRANCHIATA.

In this order the gills have vascular, interfilamentary, and interfoliary
junctions ; and the mantle is always united at one or more points, and there are
generally two adductor muscles. The order is the largest of all, and comprises
nearly sixty different families, of which only the most important or remarkable
can be mentioned. In the first (Submytilacea) of several suborders into which
the order is divided, mention may be made of a curious little species of the
family Carditidce, namely, Thecalia concamerata, which is a native of South
Africa, and remarkable for a cup-like process formed by the female within the
ventral margin of the valves, serving as a nursing-pouch for the young. Milneria
minima, a Californian species, forms a similiar marsupium. In the family
Cyprinidce, Tsocardia cor is one of the finest of the British bivalves ; and is a
large strong globose shell, with the umbones prominently curved anteriorly. The
ligament is external, and the hinge-teeth are strong and of peculiar form. The
animal has short siphons, large gills, and a small foot for burrowing in the sand.
In the Lucinidce the shells are mostly white, round, globose, or compressed, and
peculiar on account of the great length of the anterior muscular scar, which falls
within the uninterrupted pallial line. Sometimes the animals have only a single
branchial lamella, and the foot is generally slender and without byssus. The
families Leptonidce, Galeommidce, and Chlam.ydoconchidce also belong to this
order. Lepton often lives commensally with Crustacea, Galeomma has the mantle
reflected over a considerable part of the valves, and in Chlamydoconcha the shell
is wholly covered by the mantle, a unique feature among the bivalves. The family
j$Jtheriido3 includes a few remarkable bivalves known as fresh - water oysters.
They occur in the Nile and some other rivers of North Africa, and some parts of
South America. When young, jEtlieria is a freely creeping mollusc, but when
adult becomes attached to stones and other substances like the oyster. The shells
are irregular in their growth, and are of an olive-green colour. The somewhat
pearly interior of the valves is marked with two adductor scars, and the pallial
line is entire. They may be regarded as irregular forms of Unionidce without
a foot, modified for a sedentary life.

The numerous kinds of fresh- water mussels ( Unionidce and Mutelidce) occur
in the lakes and rivers of all continents, and the large islands of the Malay
Archipelago and New Zealand; although in most of the smaller islands they

BIVALVES.

411

are unknown. North America, and especially the drainage-area of the Mississippi
and its tributaries, is the great home of the Unionidce. The species may
be counted by hundreds, some being the most remarkable and beautiful that
exist in any part of the globe. The shells are usually equi valve, and joined by
an external ligament, but exhibit great variation in shape. The hinge is some-
times destitute of teeth (Anodonta, Mycetopus) ; or powerfully formed with
strong complex interlocking teeth, as in many of the North American forms ; or
it may consist of very numerous teeth on a straight hinge-line (Pliodon),
recalling the form of hinge obtaining in the Arcidce. The exterior is covered with
a thick, often glossy periostracum, varying in colour, the prevailing tints being

large iuver-mussel, Anodonta cygnea (nat. size).

greenish olive, brownish yellow, brown, and black. Many are beautifully rayed
with green. The solidity of many of the species — especially the North American
forms — is remarkable, although others are thin and fragile. Some are pearly
within, and others white, pinkish purple, salmon -colour, yellow, or iridescent.
The shells are marked with two adductor scars, and the pedal scars are also often
clearly visible, while the pallial line is uninterrupted by a posterior sinus. The
animal of Unio has the lobes of the mantle free, excepting posteriorly, where
they are connected, forming two orifices, the lower or branchial for the passage of
the water to the gills, and the upper for excretal purposes. The former is
fringed with several rows of papillae. The foot is large, thick, tongue-shaped,
and used as a creeping and burrowing organ. The sexes are united in the
European species, but distinct in the American. A remarkable feature in con-

412

MOLLUSCS.

nection with the Unionidoe is the parasitic life of the early stages. The eggs,
after being hatched between the gills of the parent, and having undergone the
first stages of development, subsequently develop into minute bivalves, each valve
having a hook-like process on the front edge, and are expelled from the brood
pouches. They at once attach themselves to some extraneous object, by means of
a byssal thread, and at this stage are known as Glochidia. They attach them-
selves, as soon as possible, to the gills and other parts of fishes, by means of the
valve-hooks, and there complete their metamorphosis, finally quitting their host,
sinking to the bottom, and assuming the parent form. Four species are found

pearl-mussels (Unio r.iargaHtifer), showing pearl within the shell, and detached pearls (1-8).

in Britain, one of which (Unio margaritifer) is famous for the pearls it
produces. Some of the rivers of Scotland, and the Conway in North Wales,
have always had a great reputation for their pearl-fisheries. Although not equal
in lustre to the Oriental jewel many of these river pearls are beautiful. Unlike
Unio, the Dreissensiidm, as represented by Dreissensia, have the mantle-margins
united ventrally, with an anterior opening for the slender foot and byssus, and
prolonged posteriorly into two siphons. The shell is shaped like the common
marine mussel. The European D. polymorpha was first noticed in England about
seventy years ago, and is supposed to have been introduced attached to
Russian timber.

Suborder Tellinacea.

This group includes the families Tellinidce, Scrobiculariidce, Donacidcv,
Mactridoe, Mesodesmatidce, and Cardiliidce, the first of which is the most ex-
tensive, and contains the most beautiful forms. Here the animal is remarkable
for the great length of the slender separated siphons, the fringed mantle-margins,

BIVALVES.

4i3

and large labial palpi and foot. The shells are nearly always compressed, subequi-
valve, joined by an external ligament, and furnished with hinge-teeth. The scars
of the adductors are far apart, and the pallial impression is generally very deeply
sinuated. None of the bivalves are more beautifully coloured than the tellens,
the prevailing tints being purple-red, crimson, and various shades of yellow.
The surface-sculpture of the valves is often beautiful and delicate. Tellens live
in sand or mud at slight depths in every sea, and the species may be counted in
hundreds. Nine species of Tellina are British. The Scrobiculariidce form a
smaller and less showy family than the preceding, the shells being united by an
internal ligament, and sometimes by an external one also. The soft-parts are
like those of the Tellinidm. Some species of the genus Abra have been dredged
at enormous depths, both in the Atlantic and Pacific, but the majority of the
family have been obtained in comparatively shallow water. The British Scrobi-
cularia piperata buries itself in the mud of estuaries, and can extend its siphons
five or six times the length of its shell. Although in some respects the wedge-
shells (Donacidce) agree with the Tellinidce, they differ as regards the gills. In
Donax the shells are of a triangular or wedge-shape, and have the inner margin
of the valves crenulated. They are united by an external ligament, and furnished
with cardinal and sometimes lateral teeth. The wedge-shells live buried in the
sand in shallow water in warm regions all over the world, and three species occur
on the British coasts. The genus Iphigenia, which has no lateral teeth, inhabits
estuaries on the coast of Africa, Brazil, the West Indies, and Central America.
In the mactras (Mactridce) the shells are often more or less triangular, and
have an internal ligament, the siphons being united the entire length, and
fringed at the ends. About one hundred and fifty species of Mactra are
known. They occur on sandy shores in most parts of the world at shallow
depths, six being British. This family comprises a large number of genera and
subgenera, mainly distinguished by modifications of the hinges ; Mulinia,
Spisula, Standella, Rangia, Rceta, and Eastonia being the more important. The
remaining familes, Mesodesmatidce and Cardiliidce, are not of special importance,
and may be passed without further reference.

Suborder Veneracea.

In the Veneridw, which form the first family of this group, the animal
has rather short, more or less united siphons, with fringed openings. The
mantle is open in front for the passage of a tongue-like foot, which is sometimes
furnished with a byssus. The shells are solid, equivalve, and often beautifully
coloured and sculptured, with the hinge-teeth large and divergent, and the
ligament external. In the typical genus Venus the shells are more or less
circular, globose, and often have the surface cancellated, and the inner edge of the
valves crenulated. There are several British forms of Veneridce, but none are
eaten to any great extent. On the contrary, the large Venus mercanaria — the
clam of the Atlantic States of North America— is sold in large quantities in
the fish-markets of New York and Philadelphia. In Dosinia the shells are
more compressed, circular, and marked within with a deep, narrow, pallial

414

MOLLUSCS.

sinus. In Circe, on the contrary, the mantle-impression is unsinuated. The
shells of Tapes are longer than the typical forms; the foot is long, grooved,
and frequently furnished with a byssus, the siphons being separate at the
ends and beautifully fringed. They are most abundant in the warm seas of
the Eastern Hemisphere, but four species range as far north as England. The
large species of the allied genus Cyrena are found in brackish water at the
mouths of rivers, and in mangrove-swamps; while the smaller forms known
as Corbicula, Spkozrium, and Pisidium occur in fresh water in most parts of
the world. The shells of the last two groups are very similar, but the animals
are readily distinguished by the number of the siphons. In Sphcerium there are
two which are united at the base, but separated at the extremities, whereas in
Pisidium only a single anal siphon is present. In this genus the water is
conveyed to the gills through the pedal opening of the mantle. There are four
British species of Sphcerium, and five of Pisidium, all of which possess the
faculty of floating in an inverted position at the surface of the water, or they
suspend themselves from the surface by a fine byssal thread. One species (P.
pusillum) does not require a constant, or even a frequent supply of water, often
living at the roots of bog-moss and grass, and it has also been found between the
bark and wood of fallen trees in moist places.

Suborder Cardiacea.

The Cardiidce, Tridacnidce, and Chamidcv are the principal families belonging
to this suborder of which there are living representatives, but a few extinct
families, such as the Hippuritidw, are also considered to belong here. The cockles

(Cardiidce) abound in shallow water in most
parts of the world, where there are sheltered
sandy bays. Some of the exotic forms are
beautifully sculptured, and their colours also
are often very bright and varied. The animals
have short fringed siphons, and the long foot is
bent and used for leaping. Probably many are
eatable, like the common cockle. In addition
to this kind, nine species are found on the
British coast. The typical species of Cardium
have the convex valves ribbed, the ribs inter-
locking at the margins. In Lwvicardium the
shells are smooth, in the beautiful Cardissa they
are flattened, heart-shaped, and keeled at the
sides. The true clams (Tridacnidce) differ from
other bivalves with united mantle -margins in
having only a single adductor muscle, like the
oyster, the anterior being obsolete. The mantle
has three distant openings, pedal (d), branchial (a), and anal (b). The foot is
small, finger -like, and capable of producing a stout byssus (e). The shells are
equivalve, ponderous, with a few stout ribs radiating from the umbones, and

valve and soft-parts of Tridacna.

BIVALVES. 415

terminating on the edge of the valves in pointed projections. The genus Tridacna
contains the largest of all bivalves, T. gigas sometimes measuring more than a
yard in length, and weighing as much as 500 lbs. The animals are gorgeously
coloured, and a mass of them nearly a mile in extent has been compared to a bed
of tulips. The six or seven species are found in hot latitudes, such as the Red
Sea, and Indian and Pacific Oceans. The adductor muscle is said to be good
eating. Hippopus differs from Tridacna in having no gape in the anterior end of
the shell for the passage of a byssus. H. maculatus is one of the most common
shells used as ornaments. The Chamidaz are remarkable for their strong irregular
oyster-like shells, which are often brilliantly coloured, and covered with spines or
ridges like the thorny-oysters. The shells exhibit two well-marked muscular scars,
strong hinge-teeth, and an external ligament. These bivalves inhabit tropical or
subtropical seas, and are usually attached by one of the valves to rocks. The
animal has the margins of the mantle united, excepting at the siphonal openings
and the pedal orifice. To a mollusc leading a stationary life, and not given to
spinning a byssus, a foot would appear to be useless ; nevertheless Chama
possesses a reduced form of this member, but what purpose it serves it is difficult
to conjecture. Some of the fossil members of this family, Diceras and Requienia.
for example, have remarkable shells, quite unlike those of the existing forms.

Suborder Myacea.

In the family Psammobiidce the typical genus Psammobia has the siphons
very long, slender, and separated as in Tellina, the foot large and tongue-like, and the
edges of the mantle fringed. The shells are long and narrow, compressed, slightly
gaping at both ends, generally somewhat obliquely truncate posteriorly, often
brilliantly coloured, and beautifully sculptured. Four species occur on the British
coasts. The gapers (Myidw) take their title from their widely gaping shells, which
are covered with a wrinkled periostracum extending also over the siphons ; these
being united their whole length, and fringed at the ends. My a arenaria, a common
British species, also abounds on the sandy shores and mud-flats of the Eastern States
of North America, where it is eaten in quantities. The clams, as they are commonly
called, live in deep burrows in the sand or mud, the shells often being a foot below
the surface. A recent writer observes that when the flats are covered with water,
the clams extend their long siphons up through the burrow to the surface of the
sand, and through one of these tubes the water and its myriads of animalcules are
drawn down into the shell, furnishing the gills with oxygen, and the mouth with
food, and then the water, charged with carbonic acid and faecal refuse, is forced
out of the other siphon. Two species of Mya constitute the staple food of the
walrus. The Solenidw, or razor-shells, are also great sand-burrowers, and indeed
bore with such rapidity, and to such a depth, that they often elude capture. They
possess very elongate shells, and are remarkable for the great development of the
foot. They not only burrow in sand, but also have the power of darting through
the water like scallops. They are eaten by the poorer coast population. In the
Saxicavidxz the species of the typical genus Saxicava are some of the few bivalves
which have the power of boring into limestone and other soft rocks, although they

4i6

MOLLUSCS.

more often hide in crevices or at the roots of seaweed, mooring themselves by a
byssus. The shells are very irregular, their form varying according to the hole or

crevice they inhabit. In the Gastrochamidcv,
forming the last family of this group, Gastrochcena
comprises bivalves which live buried in the sand.
These form a long, slender, club-shaped fragile
tube, covered with adhering particles of sand, and
divided off by a partition into two portions, the
anterior containing the shell, the posterior or
narrower end the siphons. The animal of the
allied Rocellaria is similar, but forms no tube, and
has the habit of boring into solid rock, shells, and
other substances ; R. dubia being found in lime-
stone, and even granite, on the British coasts.

animal [a) and case (b) of Rocellaria.

Suborder Pholadacea.

The boring Pholadidce and Teredinidce are the only families contained in this
suborder of the group, the former perforating clay, chalk, limestone, and even
gneiss. Their shells are always white, thin, but hard and strong, and ornamented
Math prickly rasp-like sculpture. They gape all round the valves, meeting only at
the hinge and the opposite margin. Accessory plates generally occupy the vacant
spaces. The valves
have no hinge-teeth,
and are not connected
by a well - defined
ligament, like most
bivalves. The

animals have long
united siphons,
fringed at the aper-
tures, and enclosed in
a tough skin, which
is often protected by
cartilaginous cup-like
processes. In the
typical Pholas the
foot is well devel-
oped, and probably
forms the principal
excavating instru-
ment ; the shell being
used as a file to

enlarge the crypt as the creature grows. Xylophaga and Martesia bore into
floating wood. Species of this family are met with everywhere, and about half a
dozen occur on the British coasts. In some parts of Europe Pholas is considered

Pholas in its burrow (nat. size).

BIVALVES.

4i7

a delicacy, and many species are highly phosporescent. In the second family the
ship-worm {Teredo) is only too well-known on account of the amount of damage it
does to submerged timber. It matters not whether it be oak, pine, teak, or
mahogany which it attacks, soon the timber is riddled through and through, and
rendered useless. In former times, before the invention
of copper-sheathing, immense damage was inflicted upon
shipping, and the piles of piers and harbours were con-
stantly having to be renewed through the ravages of
this pest. The Dutch have been great sufferers, and
at one time such depredations had been made on the
piles which support the dykes of Zealand and Friesland
as to threaten them with total destruction. The animal
is practically nothing more than an extremely prolonged
Pholas. The siphons are of immense length, in some
cases from two to three feet long, united except towards
the ends. On the contrary, the body itself containing
the principal viscera is small, and protected by a
globular, bivalved shell, open both in front and behind.
The gills are narrow, elongate, and prolonged into the
branchial siphon. The siphons secrete a shelly lining
to the burrow, and at the point where they separate
there are a pair of calcareous plates, or pallets as they
are termed, probably used as a means of defence, in
closing the tube after the siphons have been retracted.
Ship- worms generally bore with the grain, only turning
aside to avoid a knot or any other obstruction; and
although their burrows are almost touching, they
seldom appear to run into one another. The animal
does not feed upon the wood it excavates, but ejects it
in small particles through the siphon. The foot is
probably the burrowing organ, but the method of
excavation is still imperfectly understood. Hyperotus,
Nausitoria, Xylotrya, and Cyphus are other forms of
Teredinidce ; the last named constructing a strong,
shelly tube, sometimes a yard long, and two inches in
diameter, in which the creature lives buried in the sand.

Suborder Anatinacea.

This, the last suborder of the Eulamellibranchiata,
contains thirteen families of which only a few are of ,
general interest. Of the Pandoridce, the typical Pan-
dora is distinguished by its compressed, internally pearly shell, which is sometimes
semi-lunate in form ; the right valve being flat, and the left somewhat convex.
P. inonquivalvis is a common British species. In Myadora, an allied genus, the
left valve is flat, and the right convex. The species of the third genus, Myochama,

vol. vi. — 27

4i8

MOLLUSCS.

attach themselves to other shells by their right valve, the left being ornamented
with radiating ridges. Among the other families, Anatina, Thracia, and Phola-
domya are interesting genera, the last on account of its rarity in the living condition,
and its numerous representatives in bygone ages. Brechites, or Aspergillum, is
remarkable, as it is only in the earliest stages of existence that it presents the
appearance of a normal bivalve. It subsequently forms an elongate tube, open at

one end and
closed at the
other by a
frilled disc full
of holes, like
the rose of a
watering - pot ;
e mb r yonic
valves being
embedded in

the surface near the rose. The illustration shows the contracted animal extracted
from the shell, (e) indicating the siphonal openings, (c) the mantle aperture, (b) the
anterior side, (a) the mantle, (d) foot opening.

a B

Brechites vaginiferus.
A, Animal contracted, withdrawn from shell ; B, Anterior end of the shell.

Order Septibranchiata.

The members of this group are readily distinguished by the circumstance that
the gills are transformed into a muscular septum, extending from the anterior
adductor to the separation of the two siphons, and surrounding the foot, with
which it is continuous. This septum presents symmetrical orifices. The siphons
are sometimes short, or more or less produced. There are two adductors,
and the mantle -edges are united at three points. There are two families,
namely, the Poromyidcv and Cuspidariidce. Of the former, Poromya has the
siphons short, unequal, separate, and surrounded by a tentacular fringe ; each
half of the septum having several groups of lamellae, separated by orifices ; the
foot being slender, long, and the palpi larger. The shells are often minutely
granular and somewhat pearly within. The species are small, few in number,
and mostly from very deep water. Silenia is a deep-water form, dredged in 1950
fathoms, about eleven hundred miles south-west of Australia, and also in the South
Atlantic at the enormous depth of 2650 fathoms. The Cuspidariidce is a more
extensive family, and although the species are nearly all small, some are elegant in
form, and prettily sculptured. The shells have been classified by characters derived
from modifications of the hinge, and the surface ornamentation. The siphons are
longer than in the Poromyidce and united with tentacular fringes at the ends ; the
foot is moderately long and pointed, the labial palpi are rudimentary or wanting,
and the branchial septum is pierced with isolated symmetrical orifices. The shells
are mostly transversely ovate, and produced posteriorly into a more or less elongate
rostrum. They are found in all seas, in depths ranging from a few fathoms to over
three miles.

EDGAR A. SMITH.

CHAPTER XII.

Moss-Animals and Lamp-Shells,— Subkingdom MOLLUSCOIDEA.

The exact positions in the animal kingdom of the Bryozoa or moss-animals, and
the Brachiopoda or arm-footed animals, which are generally united under the name
of Molluscoidea, is still far from settled. The Brachiopods were long placed with
the Molluscs, and the Bryozoa with the Corals and Sponges ; but fuller knowledge
made it evident that the Bryozoa did not in any way belong to the latter. Next,
they were classed with the Rotifers, or wheel animalcules, under the name of
Ciliata, as a kind of appendage to the worms, while by others they were grouped
with the Ascidians. They are here placed with the Brachiopoda, not because the
two groups are really related, but simply because they are alike in having no
established place in the classification of the animal kingdom. It is true that the
Bryozoans and the Brachiopods are sometimes classed together because of the
similarity of their development, and also for certain supposed anatomical resem-
blances between them ; but these latter are far from convincing, and the similarity
of their larval histories has been disputed.

Moss- Animals, — Class Bryozoa.

The moss-animals almost always live in colonies, the individuals of which are
joined in a number of different ways to form stocks. The individual animals are small,
and the stocks generally also small, never forming anything approaching the masses
of substance yielded by those of the corals. The structure of the Bryozoan animal can
be studied in the accompanying figure, which shows, greatly magnified, the external
outline and the inner organs of a single individual belonging to the stock of a fresh-
water form (Paludicella) from Belgium. The individual figured has been detached
at its base from the one below it, and the one next above is broken off. The body is
represented by a chamber or cell, in this case somewhat elongated. Its walls are stiff,
except at the anterior end, where they are flexible enough to allow the crown of ten-
tacles (a) to be protruded as in the figure, or to be withdrawn by means of muscles
(m). One of these muscles is seen to be specially powerful, and runs through nearly the
whole length of the cell. The mouth is at the anterior end of the body, surrounded
by the circle of ciliated feelers or tentacles (a). The alimentary canal, which com-
mences with a muscular pharynx (6) hangs down in the form of a loop into the
body -cavity, the stomach (g) being its lowest portion. Its terminal portion runs
again towards the anterior end, so as to open not far from the mouth (at c). The
whole alimentary tube is but loosely fastened to the body- wall, its chief attach-
ment being by means of a single short strand at the end of the stomach called the
funiculus, and shown in the illustration. In all adults, two masses of cells are

420

MOLLUSCOIDEA.

found attached to the wall of the chamber, the upper (o) yielding eggs, while
within the lower (t) the male elements develop. Moss-animals are therefore her-
maphrodite, the fertilisation of the eggs being effected by the two elements ming-
ling freely together in the body-fluid. In all
essential points, the above description would
apply to any one of the seventeen hundred
species, fossil and extant, which are known.
Among the larger colonies may be
mentioned certain fresh- water genera, found
attached to the roots and branches of
water-plants, which may form considerable
masses ; but these stocks are dull in colour
and very inconspicuous, the beauty of the
minute individual animals themselves being
invisible to the naked eye. Some fairly-
sized forms occur also among the marine
genera, which are often marked by the
great variety and beauty of their stocks.
Many of these are delicate branching or
tree -like growths some inches in height;
take, for instance, the sea-mats (Flustra),
or again, the still larger and more beautiful
lace-corals, Neptune's sleeves, such as are
shown on p. 421, which, in spite of their
name, are not true corals but bryozoans.
The figured lace-coral (Retepora) is found
in the nets used on the shores of the Atlantic
Ocean and Mediterranean Sea. When
fresh, the stocks — which resemble a fine,
cup-shaped, or folded and frilled piece of
lace — seem to be covered by a reddish
organic mass, out of which arise the delicate
tentacular crowns of the individual animals.
These are, however, too small to be seen,
except with a magnifying glass. When the
soft -parts are removed, the stock is of
dazzling whiteness, consisting chiefly of the chalky substance which binds the
separate individuals together into a colony. Between the open meshes of the
lace-work, multitudes of minute apertures are to be seen, which are the openings
of the individual chambers or cells containing the bodies of the animals, and
into which they can withdraw their tentacular crown as above explained. Another
lace -coral from the Mediterranean is shown on p. 422. It rests upon a branched
structure, a common calcareous alga which grows on a stone. The individuals of
this genus (Lepralia) are arranged in rows, and are further distinguished from
Retepora and other moss-animals by the fact that the animals occur only on one
side of the stock. We mention these lace-corals because of their being com-

SECTION OF AN INDIVIDUAL OF Pdludicella

(highly magnified).

MOSS-ANIMALS.

421

paratively conspicuous ; but we might have chosen any other of the many beautiful
but less conspicuous forms. On any sea-coast a harvest of them can be gathered
in a few days. Certain species are almost always to be found on nearly every
leafy seaweed, and where the bottom of the sea is favourable, stones and the
shells of molluscs, both full and empty, are covered with stocks of Bryozoa, often
only discoverable by means of careful examination with a magnifying glasa

Owing to the . .

hardening and
frequent calcifica-
tion of the greater
part of the body-
wall to ^orm the
cell into which
the anterior part
that always re-
mains soft can be
withdrawn, these
animals are often
found as fossils.
The marvellous
variety of forms
presented by these
delicate little
stocks is in each
case determined
by the particular
manner of bud-
ding. The first
animal which, by
budding, gives rise
to the stock is
produced from an
egg, and begins to

bud as soon as it has become attached. In each family or species the buds appear
at special points, and assume definite positions with regard to the parent individual.
The smallest variation in this respect causes the profoundest changes in the forms
of the stocks produced. Their classification is determined principally by the
structure of the mouth and of the tentacle crown, as may best be gathered from a
few examples. We take first the subclass Ectoprocta.

Order Most of the fresh -water moss -animals belong to the order

Phyiactoi»mata.phyiact0iggmata) so-called because the mouth is provided with a
tongue-shaped lid. The crown of tentacles, which is also a gill, is horseshoe-
shaped, and the whole surrounded at its base by an integument forming a kind of
calyx or cup. , The chambers or cells are either quite soft or else horny, and are
thus not found in a fossil condition. Later on in this volume is described a
colony of sea-anemones which, instead of being fixed, as are most stocks, are

lace-cokal, or Neptune's sleeve, Retepora cellulosa (nat. size).

42 2

MOLLUSCOIDEA.

able to travel about ; a colony of moss-animals capable of locomotion is figured
on p. 425. These remarkable moving types (Cristatella) form flattened,

elliptical colonies, which creep
along on a kind of flat foot, follow-
ing the direction of the light.
The question may be raised as to
how the many separate individuals
manage to move in the same
direction. Even if an external
stimulus, such as light, should
stimulate the individuals in the
same way, this seems hardly
sufficient to account for the
movement of the colony, without
some nervous system connecting
the polyps and co-ordinating the
movements of the colony. As a
matter of fact, such a system does
exist. While each separate animal
is provided with a nerve-ganglion
between the oesophagus and the
posterior opening of the alimentary
canal (c in the illustration on p.
420), and with the nerves necessary
for its own individual organisation,
the Bryozoan colony, as such, has
a special nervous system which is connected with the individual systems, and
runs from one to another through the apertures by means of which also the body-
fluids circulate throughout the colony. This colonial nervous system no doubt
regulates the movement of the stock.

Order In contrast to the Phylactolaemata are the Gymnolsemata, those

Gymnoiaemata. Bryozoa in which there is no lid to the mouth, and in which the
tentacles are arranged in a circle on a disc instead of in the shape of a horseshoe ;
the name given to such forms denoting the naked condition of the mouth. These
naked-mouthed Bryozoans are far more numerous than those with lids to their
mouths. Paludicella, which is fully described on pp. 419, 420, is one of the few
fresh- water forms belonging to this order. Here the crown of tentacles cannot be
completely protruded, and thus appears, even when most extended, to be surrounded
by a double collar. A numerous group of this order are the marine Chilostomata,
or lip-mouthed Bryozoa, of which the sea-mat (Flustra foliacea), common in the
North Sea, is an example. The magnified cells shown in the illustration represent
the harder portion of the animals, into which the soft anterior portions can be
withdrawn. The openings through which the tentacles protrude lie crosswise,
and each is provided with a lip-like elastic lid. Each individual can thus take
refuge within its chamber and close the lid. Other genera which, unlike Flustra,
have no lid, can close the aperture by means of muscles. The colonies of sea-mats

lace-coral, Lepralia (nat. size).

MOSS-ANIMALS.

423

sea-mat (Flustra foliacea).
a, Stock (nat. size) ; b, Five cells (magnified).

form branched leaf -like lobes very common at the seaside, and often mistaken for

seaweed. Each side of the leaf consists of a layer of closely crowded individuals.

The cells only partly calcify, so that when

fresh they are elastic, and the whole stock

remains very flexible. To this suborder

belong also Retepora and Lepralia, above

mentioned.

An important rise in the scale of
organisation is found in the Gymnolaemata,
especially in the lip-mouthed forms, where
a marked division of labour takes place;
that is to say, the individuals which con-
stitute the stock vary in structure and
fulfil different physiological functions.
There are structures known as zooecia,
stolons, avicularia, vibracula, and ovicells,
some — perhaps all — of which are modified
individuals. The zooscia are the normal
individuals of the colony, fully developed for most of the functions of life ; respira-
tion, taking in food, and digestion, and no doubt also for receiving sensory impres-
sions. The stolons have a much humbler function, but are indispensable for the
well-being of the colony. They are rootlike outgrowths of the stock, consisting of
very simple individuals which serve for attaching the whole colony to foreign
objects, such as stones, shells, etc. The most remarkable are the structures known
as avicularia, so called because they resemble the head of a bird. The individual
is turned into a pair of forceps, of which the large upper blade (very like the skull
and upper jaw of a bird) and the smaller lower blade (like the lower jaw) con-
stantly open and shut by means of a complicated arrangement of muscles. These
avicularia are movably attached by a short neck, and are found near the entrance
to a zooecium. They turn from side to side, snapping in all directions, and, no
doubt, every now and then catch some of the small worms, crabs, or larvae which
rest on the colony. The victims are held till they decay, and, as they break down,
fragments are drawn into the mouth by the water currents caused by the cilia on
the tentacles. These dead creatures act as baits, and attract other victims within
the influence of the same stream. These also are drawn into the mouth. On
account of these peculiar structures, the Chilostomata have been called the bird's-
head corallines. Equally interesting again are the vibracula, long thread-like
structures, attached by short stalks, which keep up a constant whip-like motion.
Their function is not clear ; but perhaps they may be specialised tactile organs, or
may help to drive the minute prey within reach of the nutritive individuals.
Lastly, we have the ovicells, or egg-receptacles, which are found at the lower ends
of the zooecia in the form of bells, helmets, or vesicles. It is uncertain whether
these are independent modified individuals or merely appendages of the zooecia,
the latter view being the more probable.

Round-Mouthed Another suborder of the Gymnolaemata consists of the Cyclostomata
Group. or round-mouthed Bryozoans. In the tube-like forms (Tubulipora),

424

MOLL USCOLDEA.

Tabulipora verrucosa.-

a, Part of a stock (magnified) ; b, A few cells (highly

magnified) ; c, A stock (nat. size).

which may be taken as typical of this suborder, the relation between the infolding
portion of each individual and the rigid cell differs from that in the Chilostomata ;
and the aperture of the cell is terminal and wide, passing into the soft anterior end

without narrowing. Tubulipora is one of
the numerous round -mouthed forms, the
stocks of which form cup-shaped incrusta-
tions, the individuals radiating outwards as
seen in the magnified figure (a). In Fig. b,
several cells are still more highly magnified.
Fig. c shows the natural size of the colony.
The moss -animals seem to be excep-
tionally rich in methods of reproduction.
There is, firstly, the sexual reproduction
above mentioned ; secondly, the multiplica-
tion of individuals by budding and stock
formation ; and, thirdly, a peculiar repro-
duction, found in fresh -water forms, in
adaptation to external conditions, enabling
the animals to tide over the cold of winter,
or the drying up of ponds, etc. This last
method deserves description. It is effected
by. means of germinal bodies, which may
be of two kinds. In the genus Paludicella,
the germs are produced in the course of a few days at the end of September by
simple constriction or breaking off of portions of the stock, which then perishes.
These detached portions vary greatly in size, and resemble buds of the same size,
which latter however remain connected with the stock. . They are, in fact, detached
buds, called winter-buds, which adhere to the dead remains of the horizontal creeping
stem of the Paludicella stock, and the next spring either grow out at the same place
into new colonies, or are swept away by the water to form fresh colonies at a
distance. The other germinal bodies, termed statoblasts, form as cell-masses on the
strand known as the funiculus, which holds the stomach in place, also at the end
of September. They are round or oval in shape, and become surrounded by a
peculiar horny transparent shell, which is brown or yellow in colour, and consists of
two valves fitted one upon the other like watch - glasses. A number of these
statoblasts may be seen inside the colony in the illustration on p. 425. The
edge running round the two valves is often widened and contains small air-chambers,
or else horny filaments which stand out radially and have barbed tips. This ring is
termed the swimming-belt, and is a hydrostatic apparatus, which supports these
winter-buds or statoblasts on the surface of the water. The complicated barbed
hooks apparently act as anchors, by means of which the passively swimming
statoblasts catch on at points suitable for their development during the course of the
next spring. As soon as. the. time -for development comes, the two valves split apart,
and the germinal mass emerges from between them. Here, then, we have an alter-
nation of generations. Out of the winter-buds and statoblasts asexually produced
individuals arise, which then reproduce themselves sexually, their descendants again

MOSS-ANIMALS.

425

-yielding winter-germs. The colony produced from the winter-buds may, however,
continue for some time to multiply sexually, but in autumn again produces stato-
blasts. These processes taken together, namely, the growth of a Bryozoan colony
by means of the budding of one individual out of another, the detachment of the
winter-buds in Paludicella, the formation of the statoblasts, and the appearance of
eggs, well illustrate the close connection existing between growth and reproduction.

a, Cristatdla (double the nat. size) ; b, statoblasts op Cristatella, with theee young animals (enlarged).

Subclass Endoprocta.

Systematists have hitherto found themselves compelled to add to the Bryozoa,
or moss -animals, certain genera whose most striking peculiarity is that the
posterior aperture of the alimentary canal lies within the tentacle-crown. These
have been called Endoprocta, in contradistinction to the Ectoprocta, in which,
as we have seen, the aperture of the intestine (c in the illustration on p.
420) lies outside the tentacle-crown. We take, as an example of the Endoprocta,
the genus Loxosoma, which might well be called the spoon-animal, since, not
only in Loxosoma cochlear, represented in the illustration on p. 426, but in
most other species as well, the side view, especially when the tentacles are with-
drawn, strikingly recalls a ladle. The body is attached to a stalk, and its anterior
portion carries a circle of from eight to twelve tentacles, provided with double
rows of long cilia. The mouth is at the lower edge of the disc which carries the
feelers, while the posterior aperture of the digestive tract lies somewhat above
the middle of the disc. The thick stalk is well provided with muscles, and is
attached by means of its foot or sucker-like end, to the point chosen by the animal,
so as to be fixed by the probably viscid secretion of a large pedal gland. The
whole animal is more or less transparent, and leads a retired life in the sea, often
hidden in the cavities of horny sponges. Although capable of slow locomotion,
Loxosoma appears seldom to move from the place once chosen. It feeds on micro-
scopic particles, brought by the stream of water kept up in the cavities of the
sponge it inhabits. This food is conducted to the mouth by the cilia of the tentacles
and by a ciliated furrow round the tentacle disc. The method of reproduction of this
animal is remarkable. Two lateral buds are seen on the mother in the illustration
on p. 426.- The young animals quickly and without any metamorphosis attain the
iorm of the parent, and may, even while attached to her, feed independently, only
falling off when mature, and becoming attached in her neighbourhood. This is

426

MOLLUSCOIDEA

not, however, the only manner of reproduction. From time to time, without any
interruption" in the lateral budding, fertilised eggs ascend from the ovary towards
the tentacle-disc, and develop into larvae which in no way resemble Loxosoma

A fixed moss-animal (Loxosoma) with lateral BUDS ( x 200). a, Stock ; 5, Swarm-larva ( x 100).

They have flat, almost shield-shaped bodies, surrounded by a ciliated margin.
After breaking out through the disc of the mother, at the stage represented in the
illustration, they pass through various changes before reaching the adult form.

LAMP-SHELLS.

The Lamp-Shells, — Class Brachiopoda.

427

We must now leave the moss-animals, about whose relationship to the rest of
the animal kingdom we know so little, and pass on to the equally enigmatical class
of the arm-footed animals, or Brachiopoda. The chief structural feature in the
Brachiopods which led to their being classed as molluscs, was their bivalve shell.
They were therefore regarded as a subdivision of the bivalves. How easily a
Brachiopod might be mistaken for a mussel will be understood by the reader who
glances at the accompanying illustrations. But whereas the shells of the mussel
are at the animal's sides, and close in front, behind, and below, the hinge being on
the back, in the Brachiopods one shell is on the back and the other underneath.
There are, in addition, other profound differences in the anatomy of the soft-parts.
A further argument against there being any relationship between the Brachiopods
and the mussels is found in the fact that no intermediate forms exist which could
facilitate the deduction of the one class from the other. On the other hand, many
zoologists are inclined to consider the Brachiopoda to be modified worms, a view
confirmed by their anatomy. Although there is little to record of the activities
of these creatures, they are worthy of attention, not only on account of their
structure, but also from their extraordinary stability. With regard to this latter
point they are almost unique in the animal kingdom (if we omit the lowest
unicellular organisms), in having remained essentially unaltered from the earliest
geological epochs. They have neither progressed nor degenerated, but have lived
on practically at a standstill, so far as organisation is concerned. The period in
which they flourished most is now long past. Not only in the number of species,
but also in the number of individuals were they once so rich that thick layers of
rock have been built up by their accumulated remains. Brachiopods are divided
into two orders ; those having shells without hinges, and those with shells hinged
together. Taking the latter order (Testicardines) first, a few of its most important
families may be described.

At the present time, the most widely spread group are the
Terebratulidce or perforated Brachiopods, to which Terebratulina,
figured on p. 428, belongs. In all species of this family, the dissimilarity of the
two shell-valves is strongly marked, one valve being larger than the other, more
concave, and perforated at the beak. The hole through the beak in this family
resembles in some cases the hole for the wick in an ancient lamp, and has thus led
to the name lamp-shells being applied to all Brachiopods. Through the perfora-
tion a short sinewy stalk emerges, by means of which the animal attaches itself to
submarine objects. The hinge at the beak consists of a pair of teeth situated on
the larger valve, and fitting into depressions in the smaller valve. Thus, although
these shells do not possess an elastic band or ligament, like that which binds
together the shells of a mussel, they are prevented from falling apart. The valves
are shut and opened by means of muscles. In consequence of the position of the
animal and of its organs, the larger more concave valve has been called the ventral
valve, and the smaller the dorsal valve or lid. The most remarkable feature in
these ancient forms is the looped calcareous framework attached to the under
surface of the lid near the hinge, and running forward towards the gape of the

428 MOLLUSCOIDEA.

shell. The differences in the forms of this framework are used for distinguishing
the families and other subdivisions of the Brachiopoda. Its form and extent can
be made out in well-preserved fossil specimens. These two spirally coiled append-
ages are the " arms," from which the class takes its name, and deserve a little closer
description. The illustration below represents the under surface of a valve of the
serpent-headed Terebratula, near the back of which the mouth opens (o). The

arms rise on each side of the mouth, run forward, bend
back again, to end in an elegant coil. We may compare
them to the crown of tentacles and other organs associ-
ated with the mouth of many worms, and of the moss-
animals, only here they are stiffened by a calcareous
skeleton. As can be gathered from their rigid calcareous
frame, they are capable of only slight movement, and
even their fringes are more or less stiff. As to the
..«_-_'.».'„ rr i ,7- functions of these arms, inasmuch as they are traversed

back valve of Tereoratuhna, ...

showing the arms. by canals, and covered with cilia, we are justified in

assuming them to be gills. The animals feed on fine
particles brought to the mouth by the streams of water set up by the cilia on these
gills. In only one genus (Rhynconella), belonging to the family of the Rhynconellidce,
do the arms themselves project beyond the shell to seize prey. The alimentary
canal is short, and ends blindly at x. The body of the animal within the shell is
enveloped in two mantle-folds closely applied to the shell ; the latter being formed
by a secretion from the outer surface of this mantle. Very simple reproductive
organs lie in vessel- like widenings of these mantle-folds. The sexes are separate,
and may sometimes be recognised by differences in the form of the shell. A pair
of membranous funnels, internally ciliated, serve as ducts for the genital products;
the free ends of these funnels open into the body-cavity, and conduct the reproductive
elements outwards. The resemblance of these funnels to the nephridia of worms,
would hardly be enough to establish a relationship between the Brachiopods and the
worms. Their relationships rest rather upon the developmental history of the
Brachiopods and the transformations they undergo. The first stages in the develop-
ment of Thecidium are briefly as follows. The developing eggs enter a pouch
formed by the lower mantle-fold, into which also the two nearest arm-fringes sink.
These latter become thicker, their ends swelling to form a pair of pads, round
which the eggs group, and to which each embryo is attached by means of a short
stalk. The embryo soon resembles a short thick annelid. The upper process
from its neck is the stalk by means of which the embryo is attached to the arm-
fringe. The small anterior section resembles a head, and carries four eye-spots
and a depression, the future mouth. There are two thicker middle segments,
followed by a fourth smaller segment, all covered with cilia. In the later
development the most posterior part is used for attachment, the head and collar-
like ring sink between the upward growing portions of the following ring.
These upward growths increase and form the two mantle-folds. These, as above
stated, secrete the shell. The illustration (6), shows the young Thecidium with-
drawn into itself, having given up the free-swimming life it led after breaking
away from its parent.

LAMPSHELLS.

429

The developmental transformations of another genus, Argiope, are very-
instructive. Its larva may not only be compared with that of a bristle-worm;
it is in reality such a larva. No further develop-
ment, however, occurs in this direction, but rather
a degeneration. It becomes transformed into a
creature which has no resemblance to an annelid.
The posterior end changes into a stalk, by means of
which the animal is permanently attached, while
the bivalve shell protects the otherwise defenceless
body. In this case we can witness the degeneration
of an animal in its own development. It begins as
if it were going to be a highly developed worm,
which seems to show that its ancestors were once
such worms, but it disappoints us; instead of
advancing in organisation, it suddenly drops back
into the lowly creature described. Off the coast of
Norway, the serpent-headed Terebratulina is found
everywhere in small numbers, at a depth of from
thirty to one hundred and fifty fathoms, often
attached to the coral Oculina. When placed in sea-
water, they gradually open their valves; those
specimens which remain attached to foreign objects
show a great disposition to move about at the ends
of their stalks. Detached specimens can be moved
about without causing the animal to close its valves.
If some of the protruded cirri be touched, they are
at once withdrawn and the valves snap together, but
soon open again. When the arms are withdrawn
the cirri are bent inwards, but when the valves open
the former are seen to raise themselves into an
upright position ; even before the shell was opened a few cirri were often protruded
and waved to and fro, as if to ascertain whether any danger threatened. An
inflowing current of water can sometimes be observed between the two rows of cirri.

Another form, Waldheimia cranium, is found near the North Cape, at a
depth of from twenty-five to one hundred and fifty fathoms, attached to stones or
barnacles. The calcareous framework in Waldheimia is long, and the oral appen-
dages are incapable of movement unless it be at their spirally coiled ends. It has
been conjectured that the two coiled ends can be unrolled and rolled up again like
the proboscis of a butterfly. These animals are more active than Terebratulina,
frequently moving about on the ends of their stalks and being more easily alarmed.
The cirri do not project beyond the edge of the shell, and are bent back when it is
closed. The genus Theeidium, whose development is described above, is distinguished
by the very peculiar calcareous framework of its arms ; one of its few living repre-
sentatives being the unstalked T. mediterraneum, figured on p. 430. In this form
the dorsal valve forms an almost flat lid for the much larger ventral valve, and is
seen in the figure standing wide open at right angles to the lower shell. The

stages op development of Theeidium
(magnified).

43°

MOLL USCOLDEA.

Thecidium mediterraneum. A, Nat. size ; B,
Section through the shell (magnified).

calcareous framework nowhere rises freely from the lid, with which it is connected
by a calcareous network. In the section (B) given in the illustration we see in the
dorsal valve the depression for the hinge on which the valve rotates. The shell is
opened by the muscles (6) which run from the bottom of the ventral valve to a
process directed backward in the dorsal valve behind the hinge. It is closed by
the muscles marked a, which lie in front of the hinge. The shells of Thecidium

become attached to submarine objects, and
are brought up in considerable numbers by
the nets of the coral - fishers between the
Gulf of Bona and Cape Rosa, from a depth
of from forty to fifty fathoms. The number
of specimens of Terebratula is small as
compared with that of Thecidium, twenty
to thirty specimens of the latter being
often found together. When first caught,
Thecidium opens its valves very wide, but
when isolated and placed in small vessels
gapes less widely. The small dorsal valve
or lid can be raised to form a right angle
with the other valve, but, when the slightest
movement is made, it snaps to with the
speed of lightning. These lamp-shells are
undoubtedly sensitive to light, even a shadow thrown upon them making them
close their shells instantly. On account of the wide gape, the , inner organs,
such as the cirri and arms, can be accurately observed. The inner surface of the
shell on which the mantle lies is so dazzlingly white, and the latter so transparent,
that the calcareous framework and the prominences on the valve are as easily seen
as if there were no intervening mantle. Externally, the shell is rarely white and
smooth, being usually covered with plants or animals which have attached
themselves to it, and the valves perforated in all directions, chiefly by boring
sponges.

The Rhynchonellidce, or beaked Brachiopods, were extremely numerous in
the oldest geological times, but are now only represented by some three genera.
The most important genus is Rhynchonella, which is one of the oldest and most
widely distributed of all known organisms, being found from Silurian times through
all subsequent strata. The living R. psittacea shows best the characteristic beak-
like process of the ventral valve ; the aperture for the stalk being found under this
beak. The valves are fastened together as in the Terebratulidce, but the calcareous
framework consists merely of two short, narrow plates, which are attached to
the smaller valve. Rhynchonella is not very numerous in northerly regions,
but empty valves are found in mud. Observations on the living animal are
rendered difficult by the fact that it is peculiarly sensitive to all disturbance,
and closes its valves at the slightest movement. The arm - spirals widen
sufficiently to allow the cirri to reach the edge of the shell ; the arms do not
appear capable of unrolling and protruding beyond the shell. The members of
another family of this order of hinged Brachiopods, the Spiriferidw, are rendered

LAMP-SHELLS.

43i

Hingeless Group.

UPPER VALVE AND ANIMAL OF

Crania (magnified).

very remarkable by the long, spirally -coiled and calcified arms. Spirifer was
very abundant in the Palaeozoic epoch, but died out with the Lias.

The second order of the Brachiopods (Ecardines), or those whose
shells are without hinges, consists of but four families, two of which
may be briefly described. The unstalked genus Crania is widely distributed,
both geologically and at the present time. Its structure is so peculiar that it
forms a family by itself (Craniidee). The shell is attached to some submarine
object by the ventral valve ; the dorsal valve is lid-
like, and the two valves connected, not by a hinge
or interlocking processes, but simply by muscles. The
best-known of the four living species (here figured) of
the northern seas, is almost always found in company
with Terebratulina, which, however, it does not follow
into the seas of Northern America. ,

The last family to be described, the Lingulidce,
is also one of the most interesting. It existed in
the oldest fossiliferous strata, and is still found living
chiefly near the shores of the warmer seas. It may be regarded as perhaps the
very oldest of the Brachiopods. Indeed, if we may look upon the hinge which
characterises the other order as a specialisation, the hingeless forms are clearly
the older and more primitive. The shell of a Lingula is thin and horny, almost
flexible, and green in colour. The valves are almost exactly similar, and, as we
have seen, they are not hinged together ; and, further, they have no processes for

the support of the thick, fleshy spiral arms. No
living Lingula is now found in European seas, but
L. pyramidata occurs on the American coasts, and
another, L. anatina, in the Philippines. The stalk
of the former, which is nine times as long as the
bod}-, does not become attached, but moves like a
worm, and again, like certain worms, makes tubes
out of sand into which it can withdraw. The
Lingulidai generally live in holes in mud, the
bottom of which is lined with sand. The shell-
covered body projects above the mud to open and
feed ; on being alarmed, it shuts and disappears
below the surface. The cilia at the mantle-edge
form a fine sieve which prevents foreign particles
from entering the gills. The length of life of L.
'pyramidata is not more than a year. The sim-
plicity of the shell of Lingula, which may best be
compared with the cartilaginous structures at the
anterior end of a chsetopodous annelid, and its occurrence in the oldest strata in
which Brachiopods are found, seems to justify the conclusion that it stands nearest
of all the class to the worm-like ancestor.

H. and M. BERNARD.

Lingula pyramidata (nat. size).

CHAPTER XIII.

The Worm-Like Animals, — Subkingdom VERMES.

Although it is convenient to have a single group in which to include the
various kinds of worm-like animals, it has been frequently pointed out that there
is no natural sanction for such an arrangement, and that it is highly probable they
ought to be divided into several subkingdoms. Accordingly, the present division
of the animal kingdom must be regarded as a convenient receptacle in which to
place such Invertebrates as cannot be readily assigned to any of the other sub-
kingdoms. This being so, it will be evident that it is only possible to describe this
assemblage of heterogeneous elements by stating that the various classes into
which it is divided resemble each other in the negative feature of not possessing
the characters distinctive of any of the other groups.

Bristle- Worms, or Annelids, — Class Annelida.

... ...

The more highly organised members of this group show unmistakable points
of affinity with the arthropods, such as Apus amongst the Crustacea, and PeripatvM,
which approaches the Centipedes. It is possible, however, to mention certain
characters, which, so far as known, serve to distinguish the bristle-bearing worms

from the arthropods. In
the worms the jaws, when
present, are not modified
appendages, but are merely
horny skeletal pieces devel-
oped from the walls of the
front end of the alimentary
canal ; the appendages, when
present, are not segmented,
but merely unjointed pro-
cesses of the sides of the
body, and certain parts of
the body are ciliated, or
beset with fine hair -like
threads, such threads being
seldom found at any stage in
the life-history of an arthropod. To distinguish the annelids or chgetopods from
the groups that follow, it may be said that there is usually a distinct prostomium,
or lobe in front of the mouth, that definitely arranged bristles are implanted in

OHOtjp of bristles of an annelid (enlarged 100 times).

ANNELIDS.

433

the segments of the body, and that the latter are defined externally by transverse
grooves, and internally by septa or partitions, which divide the body-cavity into a
series of compartments.

Many-Bristled Group, — Order Polycilota.

The Annelids of this order live exclusively in the sea, and may be referred to
two sections or suborders, the one being the wandering or roving species, which
have no fixed abode (Errantia), while the other sedentary forms live habitually in
tubes which they construct for the purpose. In the former of these two suborders
in accordance with the free
roving life, the front end of
the body is furnished with
a conspicuous lobe, or pro-
stomium, overhanging the
mouth, which bears eyes and
feelers. Those forms that
are carnivorous seize their
prey with sharp - hooked
teeth, visible at the end of
the proboscis. The struc-
ture of one of the parapodia
is shown in the accom-
panying figure. It consists
of two principal branches,
an upper (A) and a lower
(B), each being supported
by a long stout bristle (e, i).
The branches are further
divided into several well-
defined parts. For instance,
in the upper there is a con-
spicuous feeler or sensory
cirrus (a), and a bilobed
leaf-like plate (b, c), from

parapodium and bristles of a polychjETOUS annelid, Heteronereis
cerstedi (much enlarged).

the lower lobe of which

(c) projects a cluster of arrow-shaped bristles. Analogous parts may be recognised
in the lower branch, / being the feelers, at the base of which is the leaf-like plate
(k); while the larger leaf -like plate (g) supports a second and larger tuft of
similarly-shaped bristles. A well-known example of this group is the sea-mouse
of the British shores (Aphrodite acwleata), a broad -bodied, somewhat slug-shaped
creature, commonly 3 or 4 inches in length. Like many of the species of marine
worms the sea-mouse is ornamented with iridescent hues, revealed by cleansing
the skin of the mud and sand with which it is usually coated. The back is
furnished with a double row of large overlapping scales, but in the British
species these scales are concealed by a close felt of hairs, although in another kind
vol. vi. — 28

434

WORMS.

sea-mouse, Hermione hystrix (nat. size).

(Hermione hystrix), common in the Mediterranean, this coating of hairs is absent,
and the scales are exposed, as shown in the accompanying illustration. In spite
of their thick armature of spines, all the sea-mice are greedily devoured by fish

of various kinds, such as
cod, haddock, and dog-
fish. Another well-
marked family is that of
the Nereidce, in which
the predatory character,
coupled with ceaseless
activity, rapidity, and
sureness of movement
reaches its highest ex-
pression. The head of the
particular species {Nereis
incerta) represented in
the illustration shows
two pairs of feelers (a and b), as well as several pairs of longer organs of the same
nature (c), situated at the sides of the head. On the thrust-out and upturned
proboscis may be noticed the two strong, sharp-toothed jaws (d) as well as several
smaller horny teeth (e). In the worm named Heter-
onereis, which is shown at A in the next illustration,
one of the chief peculiarities is that the segments in the
hinder half of the body are not so high as those in front,
and that they are furnished with far longer bristles,
whereas in Nereis all the segments are alike, being con-
structed on the same plan as those of the front half
of the body of Heteronereis. The exact nature of the
connection between these two marine worms does not
appear to be understood. The latter, however, seems to
be a stage in the development of the former ; but not
an invariable stage, since adult examples of Nereis
produce young sometimes like themselves, and some-
times like Heteronereis. Allied to the Nereidce is Palolo
viridis, of the Samoa Islands. Of this species Stair and Powell write that " every
year the animal appears during October and November in countless numbers at
different spots on the coast; but the second swarm is even greater than the
first. . . . Both swarms seem to make their appearance on the day before the last
quarter of the moon, and on this day, but especially on the day of the last quarter
itself, the crowd of them is so inconceivably great that the sea, even far from the
shore, seems to consist of nothing else. The worms appear with the dawn of
light, and their number is at its height by sunrise, but after two or three hours all
have vanished." Curiously enough this mass of worms seems to be composed
entirely of living fragments, entire examples being never met with.

Two more types of roving predatory worms are shown in the same illustra-
tion. Of these, Phyllodoce laminosa of the French and English coasts has as many

head of Nereis incerta
(enlarged 4 times).

ANNELIDS.

435

D

as three hundred to four hundred segments, and may measure as much as 2 feet in
length ; the parapodia are flattened and leaf-like. During the day these animals
lie quietly in their
hiding - places, but
come forth at twilight
to swim about in
search of prey, when
the whole body, sup-
ported and in part
propelled by the
parapodia, executes
the most graceful
wave -like move-
ments. C shows a
species of the genus
Glycera, a compara-
tively dull coloured
form, which habitu-
ally lies hidden in
sand. These worms
make their burrows
by means of their
relatively colossal
proboscis, which is
studded with numer-
ous little warts and
teeth. From the
genus Glycera there
is naturally a passage
to the sedentary
group (Tubicola) of
polychsetous annelids,
and we may take as
our first example the
sand -worm (Areni-
cola piscatorum), re-
presented of the
natural size in D
of the illustration.
This worm reaches a
length of about 8
inches. Individuals
vary, however, much
in colour, according

to the nature of the
mud or sand in which

VAEIOUS ANNELIDS.

A, Heteronereis stage of Nereis ; B, Phyllodoce laminosa ; C, Glycera ; D, Saiid-
worm or lug-worm, Arenicola piscatorum. (All nat. size.)

436 WORMS.

they are found ; those living in clean sand being of a light tint, whereas black
specimens frequent slimy sand, strongly impregnated with decaying organic matter.
The segments of the body are not all alike ; those at the front end being
furnished with a few small, widely -separated tufts of bristles arranged in
pairs ; then follows a series in which the clusters of bristles are large, bush-like,
and close together : while the end of the body is cylindrical and without bristles
and parapodia. The goblet - shaped organ, shown in the illustration, projecting
from the head is the protruded proboscis. This worm, which is found on all
the coasts of Europe, is used by fishermen as bait. At low water, on some sandy
shores, it may be found in vast numbers.

In the family Clymenidce, to which belongs the worm known as Arenia
fragilis, the body is only divisible into two regions. The fore-part, which is of a
dirty red tint, alters its shape greatly owing to the retraction and extension of its

Arenia fragilis (nat. size)

segments ; while the exceedingly long and slender hinder part is of a yellowish
colour. A remarkable family is that of the Chmtopteridw, containing the genus
Chcetopterus, of which a specimen is represented of the natural size in the illustra-
tion on p 437. The head is funnel-shaped, with an indentation on its upper side,
and from this spring a pair of feelers. The body is marked out into three regions ;
the most striking being the formation of the five segments which compose the
middle region of the body. From the first segment of this area the parapodia
stand out like a pair of flat feelers, while the lower branches of these
feet are spread like a ruff' over the abdominal region. The upper branches of
the parapodia of the second segment unite with those of the first to form a
dorsal crest, and between these and the lower branches the skin is much swollen
and of a violet colour; the following three segments are swollen and have
relatively short parapodia. Species of these worms are found on the coasts of
Normandy and in the Mediterranean. Like many other marine animals, this
worm is phosphorescent, the phosphoric matter spreading like a cloud in the water.
In the next group the gills are in the form of small trees or branches of
threads attached to the end of the head; while the mouth is unprovided with
cither teeth or a proboscis. The creatures spend their days in tubes, from
which they can only be extracted by force. In Hermella the body ends in
a long unjointed, limbless, hairless tail, while the rest of the body bears well-

ANNELIDS.

437

developed bristly parapodia, upon the upper side of each of which there is a
tongue-shaped gill. The head is remarkable in that the two large feelers blend

""«JH^|

tube-worm {Herniella).

into one and bear a few rows of broad,
flat bristles. They are thus converted
into a stopper, which closes the mouth
of the tube when the worm is retracted.
In Terebella, forming the family Tere-
bellidce, the tubes are formed of frag-
ments of sand or shell.

In the family Serpulidai the gills
are restricted to the fore-part of the
body, and the water set in motion by
their glistening hairs brings the food
to the mouth, which is situated immedi-
ately beneath. The head-lobe is blended with the first segment, and not sharply
marked off from it, as in most of the worms hitherto described. These animals
live in calcareous (chalky) tubes, the apertures of each tube being closed — when
the worm has retreated within — by a tight-fitting stopper, formed from a modified
piece of one of the gills. The first tube made by the young worm is cylindrical

ff 1

Chcetojiterus.

438

WORMS.

and open at both ends, but as the animal increases in size it enlarges and extends
its tube by adding on layers of calcareous matter to the aperture at the head-end.

common serpula, Serpula contortuplkata (nat. size).

The species of the allied genus Sabella exude a gluey substance, and construct a
flexible, leathery tube. In some cases these tubes are covered with sand, or
pieces of shell, and completely resemble those of the Terebellidce. The species of
the genus Amphicora may be found amongst seaweed on the coasts of Europe.

sabella,. Amphicora sabella (enlarged 30 times).

The body is short, measuring less than half an inch in length, and composed
of a small number of bristle-tufted segments. Unlike the Serpulido}, the animal
habitually leaves its membranous tube in search of food, when it appears as
a lively little creature, moving with indifference and facility either forwards
or backwards.

ANNELIDS.

439

Sparsely-Bristled Group, — Order Oligoch^eta.

The most familiar representatives of this group are the earth-worms
(Lumbricidcti), characterised by the numerous short segments of the body, the
bullet-shaped, plastic head-lobe, and the hook-like bristles which form either two
or four longitudinal rows, and project but slightly above the surface of the skin.

common earth-worm, Luwhricus agricola (nat. size).

Apart from certain thickenings of the skin, earth-worms have no special organs
of sense, that is to say, neither ears nor eyes, although at the same time they are
highly sensitive to the influence of light. Their food consists for the most part of
the decaying animal and vegetable matter absorbed from the soil, which they take
in large quantities into the alimentary canal; but they also draw into their
burrows straws, feathers, leaves, bits of paper, etc., to serve for food. The muscular
strength required to overcome such obstacles is often very great, and no one would
suppose that a creature so soft, slimy, and to all appearance helpless would be
capable of the effort ; but the muscular sj^stem of these animals is in reality highly
developed, as is shown by the strenuous resistance offered to any attempt to drag
them from their burrows.

In Britain there appear to be about twenty kinds belonging to three genera, of
which the richest in species are Allolobophora and Lumbricus, Allurus including
only the square-tailed worm. Earth-worms appear to be spread over all the tropical

Phreorycies merikeanus (nat. size).

and temperate parts of the world, and in some countries attain a size far surpassing
that .of the English species; one of the largest (Microchwta rappi) being an
inhabitant of South Africa. The average length of this creature is 4 or 5 feet,

44°

WORMS.

although it is capable of stretching itself much further, and its width is about
equal to that of a man's finger. On account of their burrowing habits, worms
are not very frequently seen, although periodically — but only after heavy rains —
they come to the surface of the soil in some numbers. Allied to the earth-worms
is the rare and extremely slender Phreoryctes menkeanws, which lives from
preference in wells and shallow water, in which it may be found in the greatest
abundance in May and June, disappearing in the winter. Another aquatic
member of the group is Tubifex rivulorum, a small red, translucent little worm,
found abundantly on the slimy bottoms of ditches and brooks. These creatures
remain with the forepart of the body stuck in the slime, while the hinder end
keeps up a continual vibrating movement. Usually they are so closely packed
that the surface of the mud appears to be red coloured, and when startled, the
whole throng disappears like a flash into the slime. The clear transparent naids
behave in quite a different manner. These animals are also found in ponds

and ditches, where they
may be seen winding
themselves in and out
amongst the stems of
duck-weed. One of the
best known is the beaked
nais (Nais proboscidea),
so called from a feeler-
like prolongation of the
head, which is furnished
with two conspicuous
eyes. These worms
frequently reproduce
spontaneously by fission,
and it is not uncommon
to see one individual in
process of giving rise
to several others.
Amongst the bristle-
worms is placed the
family Myzostomatidce,
which was long a puzzle
to zoologists. The species
are all of small size, the largest, Myzostoma gigas, measuring only a little more
than a quarter of an inch in length. The body is short and oval. Its upper
side, which is variously coloured, is covered with fine threads, called cilia, and its
edges are prolonged into ten pairs of long, slender, flexible appendages, while
below there are five pairs of horny tipped parapodia, and four pairs of cup-like
suckers. All the members of this anomalous family are parasitic upon stone-
lilies or crinoids, but the degrees of parasitism are various, some kinds wandering
freely about their hosts, while others cause those curious swellings which appear
upon the arms of the infested animal. .

beaked nais, Kais proboscidea (enlarged 10 times).

LEECHES.

441

The Leeches, — Class Hirudinea.

Leeches are worm-like animals which differ from the bristle-worms mainly in
the absence of parapodia, and also of bristles, as well as in the presence of one cup-
like sucker at the hinder end of the body, and
usually of another at the anterior end. Examina-
tion of a leech's body shows that the skin is
divided into a number of close -set rings.
These, however, are not the true segments ; for,
as the arrangement of the internal organs
shows, a true segment of the body — such, for
instance, as have been described in the earth-
worm or the sea-mouse — is composed of four
or five of the dermal rings. The best known
example is the common leech (Hirudo medi-
cinalis), a species in common use fifty years ago
for blood-letting. The body is broadest in the
hinder third of its length, and from this point
it is gradually narrowed towards the head and
tail. The head end is furnished with ten eyes
arranged in pairs upon the first eight rings.
At the tail there is a large cup-shaped sucker
with a narrow neck; there is also a second
sucker placed upon the head round the mouth,
which is armed with three semicircular finely
toothed jaws capable of being worked back-
wards and forwards like a saw. The ali-
mentary canal is of enormous extent and
occupies nearly the entire cavity of the body.
Its front part, or oesophagus, is a narrowish
tube, then follows the stomach which is ex-
panded into eleven pairs of sacs, the last pair
of these being very long and stretching back-
wards side by side with the narrow intestine,
which terminates close to the large cup-shaped
sucker. The structure of the organs that have been just described explains the
utility of the leech as a blood-letter. The creature adheres to the spot upon
which it is placed by means of its front sucker, which has the mouth in the middle
of it. The jaws are then brought to bear upon the skin and start sawing their
way into it, while the blood that flows from the wound passes into the sacs of the
stomach until they are all filled ; and since the walls of the body as well as those
of the alimentary canal are highly elastic, it is easy to understand how the creature
is able to expand to two or three times its normal size. Some of the structural
points enumerated above are shown in the illustration on the next page, in which
1 is the alimentary canal, with the oesophagus (a) and the sacs of the stomach (b
and c); 2 is the head end showing the eye-spots ; and 3 is part of one of the jaws.

A, Myzostoma gigas from below ; B, portion

OF ARM OF A SEA-LILY (Antedon), SHOW-
ING THE SWELLINGS PRODUCED BY

Myzostoma.

442

WORMS.

Leeches are found in marshes and ponds with a bottom of mud or clay, and
overgrown with weeds. They cannot live long out of water and die as soon as

the skin dries, though for some
time they may protect them-
selves from this by the
excretion of slimy matter.
By day, and especially in
warm weather, they swim
about with liveliness, but at
night and in dark, foggy
weather, or on cold days they
remain quiet and curled up,
and in the autumn they
bury themselves deep in the
mud. They feed largely
upon the blood of fishes,
frogs, or mammals, but some-
times, in cases of necessity,
devour each other. After
pairing in the spring, the
suctional leeches bore into the
soft spongy ground just above
the level of the water, and at the end of July or thereabouts begin to form their
cocoons or egg-cases, one of which is shown at D in the above illustration. These
cocoons are formed of a greenish mucus, or slimy material, and in them from ten
to sixteen eggs are laid. The mother then closes the aperture, and over the whole

COMMON LEECH.

A, From above (nat. size) ; B, From the side, swimming (nat. size) ;
C, Head cut oj>en to show mouth (enlarged) ; D, Egg-cocoon (enlarged.)

STRUCTURE OP LEECH.

1, Alimentary canal — a, (Esophagus ; b, Saccular stomach ; c, Last pair of pouches.
2, Anterior end, showing eyes. 3, Jaw.

pours out a whitish saliva-like froth, which upon drying forms a spongy coating
to the case. The cocoons are placed in the burrows, and from four to six weeks
after the laying, the young creep forth. These are thread-like and clear, but like
the old ones in form ; and appear to attain their full size in about five years,
although they may live as many as twenty.

The colour of the medicinal leech is black above, generally ornamented with
pale bands. This species extends over the greater part of Europe, and has been
found in France, Germany, England, Russia, and Sweden. Another nearly allied

LEECHES.

443

species, H. officinalis, which is of an olive-green, unspotted colour, is most abundant
in the south and south - east of Europe. Other kinds are found in Morocco,
Senegal, India, and North America. In some parts of the tropics, such as India and
Ceylon, land-leeches, which abound in meadows and woods, are a terrible plague.
They live on grass or trees, are exceedingly quick in their movements, scent prey
from a long distance, and troop in numbers to the spot. Hence a person brushing
through the jungle becomes covered with them, unless some precautions are taken.
Another well-known member of the group is the horse-leech (Aulostoma
gulo), characterised by its blackish green colour, the great narrowing of the fore-

rock-leech (nat. size).

part of the body, and the presence of only three small teeth in the mouth. Many
stories are current as to the dangerous nature of these leeches, and it is even said
that nine of them will suck a horse to death ; but although doubtless a voracious
creature, it is certain that such accounts are fallacious. The horse-leech lives on
earth-worms, snails, grubs, and other leeches, and even creeps into the shells of
fresh-water mussels, and takes up a lodging there until it has devoured the inmate.
Another form that abounds in fresh-water ponds and streams is Nephelis vulgaris,
which reaches a length of nearly two inches, and has four pairs of eyes and tooth-
less jaws. It appears to feed partly on animal and partly on vegetable food.
A second group of the leeches are the Clepsinidai, recognised by the short flat
body, which towards the front is usually stumpy, and ends in a seizing disc
carrying the eyes. The gullet, which is toothless, can be protruded like a proboscis.

444

WORMS.

Different species of the genus Clepsine may be found on the leaves of water-
plants and on the under side of stones. They are grey, yellow, or whitish in
colour. Instead of burying their eggs like the medicinal leech, these creatures
carry them about, and the young after birth remain some time with their mother.
They live principally upon water-snails and young mussels. The engraving
on p. 443 represents the rock-leech, Pontobdella muricata, remarkable for being
an inhabitant of the sea, and also for having the skin covered with warts and
knobs. The body, which gradually narrows from the posterior end to the head
is of a greenish grey colour, and the anterior sucker large and button-shaped.
During the daytime these leeches usually rest partially coiled up, as shown in the
lower figure, and firmly attached by their hinder sucker to some rock ; but their
muscular strength is so great that they are able to maintain themselves extended
in an almost horizontal direction, as represented in the upper figure of the illus-
tration. They feed upon skates and other fish.

The Gephyrean Worms, — Class Gephyrea.

Gephyreans are marine, cylindrical, worm-like animals, presenting no distinct
external segmentation of the body, and possessing nothing of the nature of limbs or

gills. The skin is horny,
though not calcareous, and
often provided with tuber-
cles, hooks, or bristles. The
anterior end of the body is
furnished with a retractile
and sometimes highly-
flexible proboscis, at the
end or at the base of which
the mouth is situated ; the
alimentary canal either
traverses the body from end
to end, as in Bonellia and
Echiurus, or is coiled round
a special spindle muscle, and
returns upon its course to
open in the front half of the
body,as in Sipunculus,Phas-
colosoma, and Phymosoma.
In the last-named genus the
head is furnished with a
circle or half -circle of
tentacles. The muscular,
vascular, and nervous
systems are well-developed;
the latter consisting of a

A, Bonellia; B, Phascolosoma; C, Priapulus. (Nat. size.) Cerebral ganglion, an 03S0-

GEPHYREANS. 445

phageal collar, and a ventral chord, while the most important part of the vascular
system is a dorsal vessel which lies above the alimentary canal. This class contains
two orders, named the Achseta and Chsetifera. In the former the mouth is placed
at the apex of the proboscis, which is retracted by a special muscle as in the
Nemertine worms, and the alimentary canal opens posteriorly in the front half
of the body. Moreover, as the name of the order indicates, the integument is
without bristles. In the illustration on p. 444, B represents Pha8Colo8oma, one of
the genera of the order. Here the narrowed part of the body is the extended
proboscis, which is furnished at the tip with a cluster of tentacles. A
second family of this order is the Priapulidce, containing the genus Priapidiis,
of which a representation is given in C of the figure. In this form the body is
short, stout, cylindrical, and furnished at the tail-end with a tuft of oval papillae.
The proboscis, which in the figure is represented as protruded, is short, stumpy,
and covered with toothed ridges. The animal is found in deep water in the
seas of Northern Europe, living in burrows on the sandy bottom.

The Chastifera, which in some respects approach the Annelids, differ from the
Acheeta in having the mouth situated at the base of the proboscis, and the vent
at the hinder end of the body, as also possessing a pair of large hooks
upon the front half of the lower surface. The best known is the genus Bonellia,
represented at A in the illustration on p. 444. The proboscis is of great size,
being often many times the length of the body, and is forked at the end. The
males differ from the females, being minute, — not more than about one-sixth of an
an inch long, — covered with cilia, and living within the kidneys of the females.

The Wheel- Animalcules, — Class Rotifera.

The Rotifera, or wheel-animalcules, are small aquatic animals, varying from
an eighth to the five-hundredth part of an inch in length, and derive their name
from the circumstance that the circlets of hairs situated on the head give rise,
when waving in the water, to the appearance of revolving wheels. The head
end of the body is usually broader than the opposite extremity, and terminates in
the wheel, or trochal disc, the edges of which are variously lobed, and clothed
with the vibratile cilia, or threads. The body, which is indistinctly segmented, is
either naked or enclosed in a hard transparent case, or lorica, open at both ends,
which may be variously sculptured, and armed in front and behind with spiny
processes, as shown in the annexed engraving. The posterior end of the body,
termed the foot, ends usually in a pair of movable processes, by means of which
the rotifers anchor themselves to foreign bodies of various kinds. The mouth,
situated in the middle or at the side of the wheel-disc, is a funnel-shaped cavity,
leading into a muscular gullet (a), provided with a peculiar armature of
teeth, which serve to masticate particles of food that are swept into the mouth
by the movements of the cilia on the wheel-disc. The nervous system consists of
a single large ganglion, situated on one side beneath the disc, and sending forth
nerves to the surrounding parts, and sometimes being furnished with one or more
eye-spots. In all cases the males are smaller than the females, and further differ
in having the alimentary canal aborted and reduced to a solid chord. Wheel-

446

WORMS.

animalcules are divisible into four orders. Of these, the Ploima may be considered
the typical order of the class, on account of the numbers of genera, the abundance
of species, and the restless energy, perfection of structure, and superior intelligence
of its members. Locomotion is effected by means of swimming with the ciliary
wreath. The order is divided into two sections, the Loricata, which, as in Noteus,

represented in the annexed illustra-
tion, are protected by an enclosing
shell, and the Illoricata, which, as
exemplified by Notommata, have the
integument flexible, and the body not
protected in a shelly case. The
habits of the group show considerable
variation. Many species may be found
swimming freely or attached to water-
weeds in almost any pond, stream, or
stagnant ditch; and others, like
Brachionus, one of the Loricata, may
be seen riding in clusters on the backs
and sides of crustaceans. Amongst the
Illoricata, Balatro calvus — remark-
able for having no disc — infests small
water -worms, to which it clings by
its enlarged foot - processes ; and
Drilophagus bucephalus is parasitic
upon a water - worm (Lumbriculus),
to which it clings, feeding by means
of its modified jaws. Other species
again form internal parasites, the
genus Albertia being found in the
interior of earth-worms, slugs, and
annelids of the genus Nais; while
Notommata may be seen swimming
freely within the spheres of the
beautiful Volvox.

The members of the order Bdel-
loidea swim by means of their ciliary
wreath, and creep about like a leech.
The foot is telescopically retractile, and ends almost invariably in three toes or
claspers. In this group also the mode of life is varied. Most species are free-
living, but others attach themselves to various entomostracous crustaceans, and
Callidina parasitica is always found clinging to the appendages of the fresh-
water shrimp and the aquatic wood-louse. A special interest attaches to this
group on account of their vitality. If specimens be enclosed in a cell containing
a little sand or moss, the contents may be dried over sulphuric acid or heated
up to 200° F., or left to the neglected dust of years, and some of the little creatures
will revive if a drop or two of fresh water be added to the sand.

four-horned rotifer, Noteus quadricomus
(enlarged 300 times).

ROTIFERS.

447

The order Rhizota takes its name from its members being fixed when adult, and
usually inhabiting a gelatinous tube. The foot is not retractile and ends in an
adhesive disc or cup. In the flower-animalcules ( Floscularia), which may be found
everywhere in fresh
water adhering to weeds,
the edges of the wheel-
disc are produced into
distinct bristle - bearing
lobes ; but in the allied
Melicerta there is no such
production of the disc.

The last order,
Scirtopoda, comprises
only the two genera
Pedalion and Hexar-
thra, each of which is
represented by a single
species. The two re-
semble each other and
differ from all other
rotifers in possessing
three pairs of limbs,
ending in a fan-shaped
tuft of setae. The body
is conical with a broad
square -.cut head, fur-
nished with two wreaths
of cilia and a pair of
conspicuous eyes. In
Hexarthra, which bears
a strong superficial re-
semblance to the Naup-
lius larva of some
crustaceans, the three
pairs of limbs spring
from the ventral surface,
the first pair being considerably the largest and the third the shortest ; but in
Pedalion they are arranged round the body in pairs, one limb projecting from the
middle of the back, another from the ventral middle line and two from each side,
the ventral limb being the largest of the six. By means of these appendages
the creatures are able to project themselves through the water in a series of
jerks. Pedalion has been discovered in various parts of England, and Hexarthra
in brackish water in Egypt. The male of Pedalion is a veritable dwarf as
compared with the female, the body and limbs being greatly reduced in size, and
the latter merely represented by three stumps, each of which terminates in a pair
of long bristles.

flower-animalcule (magnified 200 times).

448 WORMS.

The Thread- Worms, or Round- Worms, — Class Nematohelminthes.

These worms are characterised by having a thread-like body, covered with
tough, elastic integument, but usually showing no distinct traces of being divided
into segments like those of leeches and earth-worms, and possessing no trace of
limbs. The sexes are generally distinct. The group is divided into the three
orders Acanthocephali, Nematoidea, and Chsetognatha.

Spiny-Headed Thread- Worms, — Order Acanthocephali.

In this order is contained the single genus Echinorhynchus, which is appro-
priately named for animals possessing a protrusible proboscis, armed with several
rows of backwardly-directed spines. The chief character in which this order

spiny-headed thread-worm, a, Nat. size ; b, Head enlarged.

differs from the next is the lack of any special alimentary canal and digestive
apparatus. In the adult stage the species of Echinorhynchus are found in the
intestines of vertebrates ; the large species figured above (E. gigas) infesting the
pig. But in order to reach its final residence in this host, it has to spend its early

THREAD- WORMS. 449

days in the grub or maggot of the cockchafer and allied beetles. These latter are
rooted up and devoured by pigs, which thus unconsciously swallow the worm.
Similarly, E. proteus of various fish lives in an immature state in the intestine of
the water-shrimp, which swallowed it while still in the egg; and E. moni-
liferus, which occurs adult in such rodents as hamsters and voles, lives during
the larval state in beetles. Another species, E. polymorphus, has to be transplanted
from the body of the water-shrimp into that of a duck to reach maturity.

Typical Thread- Worms, — Order Nematoidea.

The illustration showing the growth and structure of one of the thread-worms
(Nematoxys), an internal parasite of the frog, is intended to show the mode of
development typical of the whole group. The egg is elliptical, and contains a
mass of granular protoplasm, the external wall of which soon becomes marked out
into a layer of large cells. Meanwhile, there appears at the side a distinct notch
or nick, which, shallow at first, gradually deepens, until, as shown in the figures,
it represents the space enclosed between the head- and tail-ends of the bent-up
embryo, which may be recognised respectively by their blunt and pointed

front end op thread- worm, Enoplus (much enlarged).

extremities. The external layer of cells becomes transformed into the cuticle, and
the mouth appears as a depression at the end of the blunt head. When the
muscular system and alimentary canal are developed, the embryo hatches in the
form shown in the bottom right-hand figure. Most of the species lead a parasitic
life, chiefly in animals ; many, however, are free-living forms, occurring in damp
earth, fresh water, and the sea. A genus, with marine habits, has received the
name of Enoplus, and includes small, slim, transparent creatures, some of which
are provided at the front end with isolated bristles (as shown in the illustration
above), while many are furnished with a peculiar spinning - gland, opening
beneath the tail. According to Schneider, " as soon as the animal has fixed its
tail to something it moves on, and draws after it the secretion in a transparent
thread, which is often several lines long. One end of this thread sticks fast, and by
the other the animal floats freely in the water." The young are found in shallow
water, and may be seen crawling on the surface of seaweeds ; but the mature animals
occur at depths of from two to three fathoms. As another example of non-parasitic
species, we may take the common vinegar-eel (Anguillula), the magnified figure
of which shows that the body is bluntly rounded at the head-end, and narrowed
and pointed at the tail. The greater part of the body-cavity is occupied by the
alimentary canal, which traverses it almost from end to end. The oval particles
contained in two tubes, which unite and open by a common orifice, are the eggs.
This worm appears to live both in vinegar and paste, although it does not seem
to derive its nourishment directly from either of these substances, but rather from
vol. vi. — 29

45°

WORMS.

the microscopic fungi growing in them. These worms now appear much rarer
in vinegar than former observers have represented ; and it is suggested that the
reason of this may be that vinegar is no longer made from wine or beer ; since, in
the vinegar obtained from the two latter, there probably remained much sugar
and albumen, which form a favourable basis for the growth of fungi, and therefore
for the eels. The maturing and propagation of these animals cannot take place
in pure vinegar, but only amongst fungi, where a nitrogenous diet is offered.

development of thread-worm, Nematoxys (400 times enlarged).

Vinegar now never contains adult eels, but, at most, larvae and the innumerable
little creatures supposed to be seen upon shaking a bottle of vinegar are, for the
most part, nothing but the skin-skeletons of these animals. Nearly allied is the
wheat-eel (Tylenchus tritici), which is the cause of a serious disease to the cereal
from which it derives its name. In the ears of wheat affected by this worm the
grains are misshapen, blackish, and consist of a thick hard scale enclosing a white
powdery substance, composed of the larval forms of the worm. If grain
in this state is sown in moist ground, it merely rots; but the larvae awake to
activity, and scatter over the ground in search of another growing blade of corn.

THREAD- WORMS.

45*

If they fall in with one, they start to creep up it, and mounting ever higher and
higher, as the corn grows, ultimately succeed in reaching the summit. They then
attack the soft
grain, bore into
it, and form gall-
like swellings, in
the middle of each
of which there is
a larval worm.
Here the worms
quickly develop to
normal perfection,
and after the
females have laid
a large quantity of
eggs, both they and
the males die.
Subsequently the

eggs hatch, and the larvae, which constitute the powdery substance referred to
above, make their appearance. Somewhat similar diseases are produced in other
grains by members of the same family ; and the turnip-eel (Heterodera) is very
destructive to root-crops.

Of the parasitic forms, the genus Rhabdonema has a remarkable course of
development, one species (R. nigrovenosum), which is about three-quarters of an

vinegar-eel (much enlarged).

a, female of Rhabditis — form of Rhabdonema nigrovenosum ; b, brooD-pouch. (Enlarged.)

inch in length, living, sometimes in great numbers, in the lungs of frogs. This
species is hermaphroditic, and produces innumerable young ones, which bore their
way from the lungs into the alimentary canal of their host, whence they are
expelled with the remains of their food. They then develop in a few days into
free-living, separately-sexed individuals, bearing a close resemblance to another
free-living worm (Rhabditis). These individuals breed; the females bear one
or two young apiece, and these, after devouring their mother's vitals, and making
their escape by bursting through the skin of her body, pass through a frog's mouth
into its lungs, and become the hermaphrodite adult. Another species (R. strongy-
loides) is of interest, inasmuch as it is parasitic in man in warm climates.

Two more remarkable Nematoids may be mentioned, both of which infest
insects. The first of these, Atractonema gibbosum, is found in numbers in the
body-cavity of the larval and adult stages of the midge ; the completely-formed

452

WORMS.

worm reaching a length of nearly one quarter of an inch. Its shape is unusual,
on account of the presence of a hump projecting like an excrescence from the

surface of the abdomen, some distance
from the tail-end. When fully formed,
this excrescence amounts in size to half
the length of the entire worm, and contains
the young, which, after making their
escape, undergo a short development in the
body-cavity of the midge, then reach the
outside, where they are transformed into
mature males and females. After the
pairing of the sexes, the males perish,
but the females again enter the larva and
start another cycle of metamorphosis.
The second kind (Sphcerularia bombi),
which infests humble-bees, closely re-
sembles the first in development ; but the
excrescence, or brood-pouch, of the mother-
worm is changed into a tube, and ultim-
ately reaches a size from fifteen to twenty
thousand times as great as the parent,
which dwindles in size in proportion as
the sac grows. The life-history of this
worm is shown in the illustration, where
A is the free-living male, B represents the
free-living female, and G is the parasitic
female (w), with her brood-pouch.

Of the thread -worms infesting the
human body, one of the commonest is
Ascaris lumbricoides, which is found in
numbers varying from one or two only
to over two thousand. These worms
usually infest the small intestine, but
sometimes enter the stomach, or even
penetrate into the liver. Large examples
reach a length of 6 inches or more, and
the females produce about sixty millions
of eggs annually. These are naturally
dispersed abroad everywhere, and as the
young worm retains its power of growth
in spite of frost, drought, and, in fact, the
most unfavourable circumstances imagin-
able, and is, moreover, far too small to be noticed, we need not feel surprised at
the prevalence of the pest. The form and some of the structural characters of
this worm are shown in the two illustrations on p. 453. In the uppermost, 1 is
the male, and 2 the female, of the natural size, 3 being the egg, enormously

HUMBLE-BEE THREAD-WORM.

A, Male enlarged ; a, nat. size.

B, Female enlarged ; b, nat. size.

C, Brood-pouch of female (w) ; c, nat. size.

THREAD- WORMS.

453

enlarged ; the lower illustration depicting the upper (a) and the lower (6) side of
the head, with the prominent lips. Other mammals, besides man, are the hosts of
different species of Ascaris. For instance, A. mystax is found in dogs and cats,
and sometimes even in man ; while A. Iwmbricoides also occurs in swine. A large
species, A. megalocephalus, the female of which reaches a length of over a foot, lives
in horses and cows. A second common parasite of mankind is Oxyuris vermi-
cularis, a small, white, sharp-tailed worm, which measures about one-quarter of

human round worm (Ascaris lumbricoides).
1, Male ; 2, Female. (Nat. size.) 3, Eggs (enlarged).

an inch in length. It occurs abundantly in children and growing people. As, in
the case of Ascaris, it seems that before development can take place, the egg must
pass out of the host, and again make its entry into the alimentary canal through
the mouth. These worms are so small and
light that, when dried, every current of air
will scatter them, and they may make their
way into the alimentary canal of their host
in connection with almost any kind of food.
To the family Strongylidce belongs a danger-
ous parasite, Dochmius duodenalis, occurring
in the intestine. It is about half an inch in
length. A peculiarity of this species and
others of the genus is that the posterior end
of the male is furnished with a curious bowl-
or fan-shaped ruff, which is often supported
by thick ribs (a and c of the figure on p. 454).
that are still growing, is furnished with strong teeth (b). When this worm appears
in masses, it produces the disease known as Egyptian cholera.

The accompanying illustration is an enlarged view of the head of Cucullanus
elegans, a parasite in fresh-water fishes like the perch, and having for its inter-
mediate host the Crustacean Cyclops. The worm is about half an inch long, and
the aperture of its mouth forms an elliptical case with thick brown walls. The
female bears living young, which creep forth from their egg-cases while still within
their mother's body, where they may be counted in thousands. Protected by a
tough skin, the worms, which have reached the outside world, frequently live for
several weeks in the water on the look out for a favourable host. Having come
across, and made their way into a Cyclops, they undergo various changes, but only

head OF human round worm (enlarged).

The gullet, at least in individuals

454

WORMS.

V

Dochmius duodenalis. a, Entire ; b, Head (enlarged) ;
c, Tail (enlarged).

reach in this host a length of about one -twelfth of an inch, their complete
development only taking place after the swallowing of the infested Cyclops by a
fish. Another member of the same family is the Syngamws
trachealis, which owes its double name to the fact that the
males and females are found in pairs in the windpipes of
various birds. They sometimes occur in such numbers that
the inflammation set up by their blood-sucking suffocates their
host. The eggs appear to be brought up into the bird's mouth
by crowing, or by the choking cough that the presence of their
parent causes.
They are then
swallowed, and
pass out through
the alimentary
canal. As soon as
they have obtained
sufficient damp-
^ "ilflfl ness and warmth,

they develop in
about a week's
time into small
thread-shaped em-
bryos, with a blunt head and pointed tail. These obtain an
entrance into another, or the same bird's mouth with the food,
and thence pass into the windpipe.

Perhaps the most dangerous of all human internal parasite
worms is Trichina spiralis. In the mature stage these
creatures live in the intestines of mam-
mals and birds, where they propagate and
gradually perish. The females are about
one-eighth of an inch long, and twice
the size of the males. In both sexes
the mouth lies at the front end of the
body, which is its narrowest part; the
tail is stumpy, and in the male provided
with a pair of short processes. The
number of progeny produced by one
female may amount to some thousands,

and as soon as these are born they make their way into the
blood-vessels of their host's intestine, where they are carried
by the circulation to some more distant part of the body, and
ultimately come to a stop in one of the muscles. Here by
feeding they grow in a few weeks to four times their original
size, and form between the muscular fibres a great cyst
or capsule, in the centre of which the worm lies coiled up in a spiral. It has
not been ascertained how long the creature can remain in this immature state, but

m^

HUMAN THREAD - WORM,

Oxyuris vermicukiris
(much enlarged).

head of Cucullanus
degans (enlarged).

THREAD- WORMS.

455

TRICHINOSIS WORM COILED UP IN HUMAN

muscle (enlarged).

certainly for years, and perhaps decades. It can, however, develop no further

until introduced into the intestine of a suitable host. For instance, if the muscles

of a pig be infested with trichinae, and eaten in an uncooked state by a human

being, the immature worms are set free in the intestine of the new host, where

they grow to matu-
rity, and produce
young. To the
genus 'Filaria be-
long two other
worms parasitic
upon man, and the
cause of sickness.
One commonly
known as the
guinea -worm, and
occurring in the

tropical and subtropical countries of the Old World, lodges

itself beneath the skin, producing abscesses. It may attain

a length of several feet, and the operation of extracting it

from the patient demands considerable skill and patience.

The second species lives in the blood and lymphatic vessels,

and is said to cause elephantiasis. The larvae are sucked from

human blood by mosquitoes. When the insects perish, the

worms make their escape into water, where they attain

maturity and produce their young, which are subsequently

taken into the human body when the water is drunk.

The family of hair-worms, Gordiidce, owe their English

name to the resemblance that their long, black, slender, flexible

body bears to a hair from a horse's mane or tail, and their

scientific title, Gordius, to the peculiar habit the animals

have of tangling and entwining themselves in a way that

may be compared to a Gordian knot. The best -known

species is G. aquaticus, the average length of which is about

4 inches, although specimens three times that length have

been obtained. The width of a male is about one-thirtieth

of an inch, the females being slightly wider. The prevailing

colour is brown of various shades ; the males, however, are

always darker and more polished than the females, and are

often of a deep shining black, while the females vary from

light yellow to deep yellow-brown. Upon the middle of

the abdomen, both in males and females, runs a long dark

streak, visible even in the darkest males. Another mark by which the male

may be recognised is the bifurcated tail end. Although living a free life in

the adult condition, these worms spend the greater part of their lives, up to the

last period, in certain insects. The young hair-worms, as they issue from the

egg, are scarcely more than one twenty-fifth of an inch in length, and most

trichinosis worm, Trichina
spiralis (male enlarged).

456

WORMS.

curiously shaped ; the body being cylindrical, and consisting of a thick fore-part,
and a thinner tail-like appendage. Out of the front end of the body a sort of head
can be thrust, which is armed with two circles of small hooks, and tipped with a
horny proboscis. With these instruments the creatures, in the first place, bore their
way through the egg-shell, and, having made their escape, lie quietly at the bottom
of the water without appearing to wander in search of a host. Insects, how-
ever, in the adult and larval stage abound in most fresh waters, and sooner or later

the young worms come

S-^^£t0%&*&&$&$^

j.a.rv;e of Gordius — a, showing proboscis, and b, circlets of hooks on the
head ; c, two examples lodged in the foot of a larva of the May-fly.

across them. They then
seek out a soft spot, bore a
hole by their apparatus of
hooks, and by a series of
contractions and extensions
of the body force an entrance
between the muscle -fibres
of the limb, whence they
spread into the body-cavity
of their host. In the illus-
tration, a and b show two
views of the larva with its
armature of hooks, and c
represents two that have
effected an entrance into the foot of the larva of a May-fly. They also infest in this
way water-bugs and gnats. All these water-insects, however, are liable to be devoured
by fresh-water fish, and by this means the young hair-worms are set free in the
intestines of the fish, where they undergo their
metamorphosis, and after five or six months pass
into the water in the mature form. Nearly allied
is the family Mermithidce, containing the genus
Mermis. Like the hair-worms, they occur both
singly or coiled up and entwined with each other.
The eggs are curiously constructed, having the
form of lenticular capsules, with a pair of tassel-
shaped appendages projecting from their flat sur-
faces. Eggs of M. albicans laid in the summer do
not hatch until the spring. After remaining a
short time in the earth, the young search for insects and larvae, bore a way into
their bodies, where they gradually grow to maturity, and ultimately pass out to
lead a free life, when they pair and lay their eggs. They may be found in cater-
pillars, grasshoppers, and more rarely spiders.

eggs and larva OP Mermis (enlarged).

Arrow- Worms, — Order Ciletognatha.

The small group of worms included under this heading are of doubtful position.
They are glass-like, transparent creatures living in the sea, near the surface of
which they swim in numbers. They are most active and vigorous swimmers, as

NEMERTINE WORMS.

457

Blight bo expected from their slender build, and the presence of a large horizontal
fin at the sides of the hinder half of the body, projecting beyond the tail. The
shape of the body and the presence of the large tail-fin suggested the name Sagitta.
The head is bluntly rounded and furnished with a pair of eyes, a pair of feelers

arrow- worm (25 times nat. size).

and an armature of close-set horny teeth, all of which must be of the greatest
service to the animal in its roving, predaceous life.

The Nemertine Worms, — Class Nemertinea.

All the members of this group are characterised by having the body elongate
and flattened, at least on the abdominal side ; at the front end there are frequently
two clusters of eyes, and two apertures, one of which leads into the alimentary
canal, and the other into a cavity containing a peculiar organ known as the
proboscis. The latter, which is used as an instrument for prehension, can be thrust
out with swiftness to a considerable distance, and in many species is armed in the
middle with a sharp spike-like tooth and some smaller ones at the sides, which are
brought by degrees into use as the large median one is worn
away or fractured. This organ is shown protruded in a small
marine species (Tetrastemma obscwrum) in the illustration on
this page, and retracted within the body in the full illustra-
tion of the animal on p. 458. The creature thrusts forth its
proboscis with lightning speed at passing animals, such as
crustaceans. The figure of T. obscurum illustrates other
characters in the anatomy of these animals. The two
swellings situated in the head end and united by a cross
bridge constitute the brain or chief centre of the nervous
system ; running backwards from each to the hinder end of
the body is a long nerve-chord, supplying the muscles and
other organs of the body. The winding curled tubes, which
also run the length of the body, are the so-called water-
vessels. These worms, which have received their generic name from the pre-
sence of four eyes, are widely distributed, most of the species being minute,
and commonly found among seaweed. The worms of this group that have
hitherto been discussed have the proboscis armed with stylets, and are consequently
called the Hoplophora, or armed nemertines. The second division, namely, the
Anopla, — comprising those kinds which have no spines upon the proboscis, — contains
some of the largest species of the class, Meckelia somatotovia reaching a length of

END OF PROBOSCIS OF

Tetrastemma (enlarged).

45S

WORMS.

from 3 to over 6 inches. It is a long, flat, whitish-coloured creature, occurring on
muddy ground and between the branches of coral ; and has received its name from
the habit of breaking up into pieces at the least touch. The
vitality of the severed pieces is so great that the head end
has the power to re-form a new tail, and the tail end a new
head, and the intermediate pieces a new head and tail.
Another common kind is Folia crucigera, so-called because
its greenish body is marked with five longitudinal white
bands and transverse white stripes, forming together a
series of crosses. These worms are long and slender, reaching
a length of about 16 inches. The proboscis, moreover, when
protruded, adds another 6 inches to their extent. They are
found most abundantly in pieces of rock riddled with holes
and galleries by boring sponges, and they also intertwine
themselves amongst the prongs of branching-corals, as shown
in the illustration.

Most marine nemertines prefer rather shallow water;
but some occur at considerable depths ; and a pelagic species
from the Indian Ocean, originally described as a mollusc,
under the name Pterosoma planum, is a transparent
creature, whose internal organs, especially the chestnut-
brown digestive apparatus, are visible through the colour-
less integument. The body diminishes from the front
towards the hinder end, and at the sides is marked out by
deep notches into a series of five lobes, of which the first
pair are enormously large, and have the form of two
semicircular wings. The use of these is doubtless to enable
the creature to float or swim in the water. All the fore-
going are free living types, but we now come to forms
(Malacobdella) not unfrequently found living parasitically
under the gills of various marine molluscs. In these, the
body is short and broad and capable of but little change
in shape at its hinder end ; it is furnished with a sucking
apparatus, by means of which the animal adheres to its
host. As stated above, almost all nemertines are of separate
sexes ; and in some marine species the development of the
young is so remarkable that it is impossible to pass it by
without notice. The young which issue from the egg are
so unlike the parent, that no one would at first sight suppose
them to belong to this group. The larva, as shown on
p. 461, bears some resemblance to a helmet, and has been
named Pilidiwm. This creature, which is covered with
cilia, swims near the shore for some time, while the young
nemertine is developed inside. As soon as this has acquired
four -eyed nemertine, its cil- ^ stained a certain stage of maturity, it breaks

Tetrastemma obscurmn .'»•■•• i • i -i j_ vj?

(enlarged). from the pilidium and starts an independent lire.

FLAT-WORMS.

459

The Flat- Worms, — Class Platyhelminthes.

The flat-worms are characterised by the absence of a distinct vascular system,
and by the alimentary canal being either absent or with no posterior outlet. A
nervous system is developed, consisting either of a network of nerves, or some-
times of a distinct brain and lateral chords. The excretory organs are composed
of fine tubules opening to the exterior, and the body-cavity is reduced to a set of
slits in the tissues. For the most part the sexes are united in one individual.
Sometimes a sexual reproduction occurs, accompanied by an alteration of genera-
tions. There are three orders of flat-worms, namely, the tape - worms, the
trematodes, and the turbellarians.

cross-bearing nemertine {Polia crucigera) on a coral (uat. size).

Tape- Worms, — Order Cestoda.

The members of this extensive group are internal parasitical worms with
the body divided into a number of segments. There is no trace of an alimentary
canal, nutriment being obtained by the absorption of juices through the entire
surface of the body. The head is furnished with suckers, or hooks, or both, by means
of which the worm adheres to the walls of the intestine of the host it infests.
The nervous system consists of a ganglion in the head, and a cord on each side.
As a well-known example, we may take Tamia saginata, one of the human tape-
worms ; and since its structure and the phases through which it passes in the
course of its development are thoroughly known, a detailed discussion of its
characteristics will serve as an introduction to the study of the group. In its

460

WORMS.

mature state this worm, which spends this stage of its existence in the human
intestines, may reach a length of 5 or 6 yards. Its head is relatively minute,
being only about equal to that of an average pin in size, and furnished with
four suckers, by means of which the creature adheres firmly to the walls of the
intestine. The head is followed by a narrow piece called the neck, which gradually
passes posteriorly into the trunk. It is not jointed, but where it merges with the

a nemertine, Pterosoma planum (enlarged).

trunk it becomes marked by shallow grooves, growing deeper and deeper as they
recede from the head, until ultimately they divide up the body into a chain of
flattened, square or oblong segments, of which there may be many hundreds.
Each segment is called a proglottis, the whole series being termed 'proglottides.
The muscular system is fairly well developed, and consists of fibres running
lengthwise throughout the segments and across from side to side, and of others
passing from the upper to the lower walls. By means of these muscles the worm
is able to shift at will its point of attachment to the gut, and to lengthen or

FLAT- WORMS.

461

PILIDIUM LARVA, WITH NEMERTINE WORM
DEVELOPING INSIDE.

shorten its body to a very considerable extent. The chief centre of the nervous

system lies in the head, and from this portion, which may be called the brain,

nerves pass forwards to supply the suckers, while a single stout cord runs back-
wards on each side to the end of the body,

lying close to the edge of the segments. As

already pointed out, there is no trace of a

mouth nor intestinal canal, although there is

an excretory organ, consisting of a ring-shaped

vessel in the head, from which four tubes,

corresponding in position with the sucker, are

prolonged backwards. Two of these soon

vanish, but the others lying near the edges of

the segments, close to the inner side of the

nerve-chords and the longitudinal muscular

band, extend to the hinder end of the body, where

they unite and communicate with the exterior

by a common aperture. At the hinder end

of each of the segments these two ducts are

united by a third, which runs across from side

to side. In addition to these structures, each

fully -grown segment contains a complete set of organs for the formation and

fertilisation of eggs, of which an immense number are developed. The mature
segments begin at a distance of about a foot from the head,
and those at the hinder end of the body are the first to become
distended with eggs ready to hatch. The eggs, however, are
not laid within the human body, but the ripe segments break
off one by one, beginning with the last, and pass out of the
e intestine. The rup-

ture is effected by
the contraction of
the muscular fibres,
which acts upon the
transverse vessel of
the excretory system
of the segment in
front, in such a way
that a fresh terminal
pore is formed. The
ripe proglottis, or
segment ready for
separation, is little
more than a sac
that is crammed with

minute spherical eggs, set free by the bursting of its walls. In this way the

eggs, which, on account of their thick protecting shell, are able to withstand the

most unfavourable conditions, are disseminated abroad ; and, owing to their vast

r

HUMAN TAPE-WORMS.

a Taenia solium (nat. size) ; b, c, d, Head enlarged ; e, Segments :
/, Segment of Taenia saginata (enlarged).

462

WORMS.

EGG (a) AND SIX-HOOKED EMBRYO (6) OR

Proscolex OF TAPE-WORM.

numbers and minute size, some ultimately succeed in making their way in
connection with either food or water into the stomach of an ox. Here the egg-
shell is dissolved by the action of the digestive fluids, and a small embryo, the
proscolex, is set free. This embryo is a small round creature furnished with six
hooks, arranged in three pairs. Upon this proscolex the gastric and intestinal
juices have no effect ; but instead of undergoing further development in the
alimentary canal of the ox, it bores by means of its hooks into the blood-vessels of
its host, and is thus carried by the circulation into the muscles, liver, lungs, brain,
or other suitable resting place, where it starts its growth. Here it elongates,
and becomes larger, while the hooks drop off and the central portion liquefies, so
that a bladder of fluid is formed. When these bladders — which are oval and
about a quarter of an inch in length — are found lying side by side between the
muscular fibres of beef, the meat is spoken of as measly. The next step is the

formation of the head, which takes place in the fol-
lowing way. At one spot on the side of the bladder
an infolding of the outer skin takes place, and this
elongates until converted into a hollow sac project-
ing into the cavity of the bladder. At four
equidistant points near the bottom of the pushed-in
sac the suckers of the head appear. The head
therefore is developed outside-in, but subsequently
it is pushed out, and the embryo, which in this stage
is termed Cysticercus bovis, consists of a head, a neck,
and a bladder. Beyond this stage the tape-worm cannot go so long as it remains
in the body of the ox. If, however, the latter be killed for food, and its affected
flesh eaten in an uncooked state, the bladder and neck of the Cysticercus are
dissolved by the digestive fluids, while the head, which
is often spoken of as the scolex, fixes itself to the walls
of the intestine, its neck gradually elongates, and the
body grows and becomes divided into segments, or
proglottides. Another common tape-worm in Europe is
T. solium, which is scarcely so long as T. saginata, and
may be distinguished by the presence of a circlet of hooks
on the head in front of the suckers, as well as by the
smaller number of egg-sacs in the ripe segments. It has
long been well established that human beings share with
pigs in the breeding of this tape- worm, the bladder worm
stage (cellulosce) being found in one of these quadrupeds,
and the cycle of development similar in all respects to
that of T. saginata. In addition to being found in swine,
the bladder- worm stage of T. solium also occurs in a few
other animals, such as monkeys and dogs ; and even in
man, if through any accident an egg has been swallowed,
the Cysticercus duly makes its appearance in the muscles,
heart, brain, or eye, and may thus be the cause of very serious consequences.
Another tape- worm (T. cucumerina), sometimes found in man, frequently lives in

BLADDER-WORM STAGE (Cysti-

cercus) of tape-worm.

a, With head beginning to turn ;

b, With head protruded.

FLAT -WORMS.

463

Taenia cchinococcus (enlarged).

abundance in dogs and cats. Many other tape-worms live in these mammals, one
of the commonest infesting the former being T. serrata, distinguished by a double
row of hooks on the head. In the bladder-worm stage this species lives in rabbits
and hares. The commonest form in cats is T. crassicollis, which has a large head
and a short thick neck, its bladder-worm stage being passed in mice. Perhaps,
however, the most important tape- worm of the dog is T. camurus, interesting on
account of the remarkable features it presents in its condition as a bladder-worm,
and the serious disease, known as the staggers, which its presence in the brain
brings upon sheep. Another pest of much the same
nature is the bladder -worm known as JEcliinococcus.
The mature worm living in the dog is a small tape-
worm, scarcely more than a sixth of an inch in length,
and differs from the species hitherto discussed, in that it
consists merely of a head, neck, and three distinct
segments, of which the third or last becomes ripe and
then equals the rest of the worm in length. The head,
like that of T. solium, is furnished with suckers and
hooks, and the embryo which hatches from the egg is

armed, like the rest, with six hooks. The bladder-worm stage occurs in both men
and pigs, and each bladder becomes the brooding-place of a large number of others.
Upon the surface of the bladder several ingrowths are developed, and each of
these gives rise to a single head. As many as twelve, fifteen, or twenty may be

formed. The bladder, however, sometimes becomes more
complicated by the formation, either outwardly or inwardly,
of secondary head-producing vesicles, so that the original
cyst is enveloped by others which have arisen as its
buds. To complete the register of the tape-worms, whose
life-histories are bound up with our own existence, the
genus Bothriocephalus must be mentioned. The common-
est species (B. latus) is the largest of human tape-worms,
and may attain a length of nearly 10 yards, and be
furnished with from three to four thousand segments. It
may be at once distinguished from the species of Twnia
by the shape of its head, which is long, flattened, and
furnished with a deep cleft or slit on each side. The
intermediate hosts of this worm are fresh - water fish.
Belonging to the same class as the preceding is the strap-
worm (Ligula simplicissima), which reaches maturity in the intestine of various
water-fowl, but is found in the bladder-worm stage in the bocly-cavity of whiting,
which swallow the eggs expelled from birds. A peculiarity of this worm is, that
the segmentation of the body into proglottides does not take place.

BROAD TAPE-WOKM (BotkHo-

cephalus). a, Head uat.
size ; b, Head enlarged ;
c, Segments.

Trematode Worms, — Order Trematoda.

Some of the less highly organised members of the preceding group, namely,
those which are not segmented, are nearly related to the present section of

464

WORMS.

parasitic worms. In this class the body is unsegmented, usually leaf-like in form,
smooth-skinned, and provided with suctorial discs in the middle or at its hinder
end. There is a distinct digestive canal, usually forked, but provided with only
one aperture, namely, the mouth. The excretory organs open by one or two pores
at the hinder end of the body, and, as in the tape- worms, the male and female
generative organs coexist in one individual. Although all are parasitic, the higher
members are external parasites, and develop without migration ; whereas the lower
ones make a complicated migration, with intermediate stages of development,
spending their youth in one host, and their maturity in a second.

Many-Suckered Group, — Suborder Polystomese.

The characteristic feature of this group is the presence in the fore-part of the
body of two small sucking-discs, and also of a large one and several small ones at
the hinder end, as well as sometimes hooks for clinging. These worms are chiefly
external parasites, laying fairly large eggs, and the young develop without an
intermediate generation. One of the best known genera is Epibdella, in which

suckers are placed close to the true mouth,
giving the appearance of three apertures
of this nature. Fig. 1 of the illustration
represents a specimen of one species; in
the right-hand figure the head being curled
upwards and backwards. The posterior
sucker is large and furnished with three
hooks; the two anterior suckers are
smaller, and behind them is the mouth.
This worm is of a whitish colour, and
lives parasitically upon plaice and halibut.
Nearly related is Trochopvus, a parasite
of the gurnard, represented in Fig. 2 of
the illustration, the line to the left hand
of the illustration showing the natural size
of the animal. On the head, in addition
to the two suckers and mouth, are four
black spots, lying just in front of the last-
mentioned aperture, which are the eyes.
The posterior sucker is of enormous size,
and rosette or wheel-shaped; it is sup-
ported by nine spokes, and surrounded by
a fringed border. Fig. 3 of the same
illustration represents a species of the
allied genus Gyclatella, much magnified. This trematode is one of the most
striking members of the group. The body is oval, flat, and pure white in colour.
At its hinder end it is marked out by a deep notch on each side into three
processes, of which the. two external ones are wide and lobate, while the middle
one forms a slender tail-like appendage, supporting the large circular sucker. This

TREMATODE WORMS.

1, Epibdella ; 2, Trochojpus ; -3, Gyclatella.

FLAT-WORMS.

465

organ is supported by a set of radiating spines, eight in number, and has a soft
membranaceous rim. The head is surrounded by a circlet of small feelers. This
worm — one of the smallest of its group — lives as an external parasite upon annelids,
especially upon tube-making forms, such as Clymene.

The worms which constitute a second section of the present suborder differ
from the foregoing in possessing several sucking-discs at the hinder end of the
body. Among them is a curious creature well deserving its name of Diplozoum

life-history of double-worm (magnified).

paradoxum, since it consists of two complete, mature similar halves, each possessing
every attribute of a perfect animal (a). Each of the pointed front ends has a mouth
aperture, and close to it a couple of small sucking-discs; while each individual
has a separate intestine consisting of a median tube and innumerable side-branches.
At the hinder end of the body are two suckers sunk in a depression, and protected
by four hard buckle-shaped organs. The double- worm lives on the gills of several
species of fresh-water fish, the gudgeon and minnow for instance. The eggs are
elongate and provided at one end with a fine thread-like appendage (6). In this
egg the young (c) — which at the time of hatching is only about one hundredth of
an inch — takes about a fortnight to develop. It is covered with cilia, has two
vol. vi. — 30

466

WORMS.

eyes, and only a couple of suckers at the hinder end of the body. After quitting the
egg the larvae are very lively and restless in their movements, either gliding slowly
hither and thither, or swimming with rapidity. If unable to find the fish in whose
gills they are destined to live, they grow feeble and perish ; but if successful in
making a settlement in their necessary surroundings, they grow into the Diporpa
(d), which is flattened and lancet-like in shape, and bears a small sucking-disc on
the under surface, and a conical excresence on the back. After living some weeks
or months in this state, and gaining nourishment by sucking blood from the fish's

gills, the worms begin to join together
in pairs, one specimen seizing the
conical excrescence of another by its
ventral sucker, then, by means of a
truly acrobatic feat, the second twists
round until it is able similarly to
attach itself to the dorsal excrescence
of the first, and in this state an in-
separable fusion takes place between
the suckers and excrescences involved
in the adhesion. Another remark-
able trematode is Anthocotyle Tner-
lucci, parasitic on the gills of the
whiting, which is represented in B
of the illustration. The other worm
represented in the same illustra-
tion (A) is Dactylocotyle pollacki, a
parasite on the gills of the pollack.
Here the slender front end of the
body is much longer than in the last,
the trunk gradually expands, and is
wide and squarely cut at its posterior
extremity, upon which are four pairs
of long, stout, stalked suckers. The
foremost pair of these seem to corre-
spond to the very large suckers of
Anthocotyle. We now come to two
species of the present group of
fcrematodes which, by their manner of life, lead to the second division of the
internal parasitic forms. The first of these (Aspidogaster), found in the interior
of the fresh -water mussels, is little known; but our acquaintance with the
development of the second {Polystomum) is tolerably complete. This animal,
with a roundish body, is less than half an inch in length, and is easily recognis-
able by the presence at the hinder end of the body of a large wheel-like expansion
bearing three pairs of suckers, between the last and longest pair of which are a
couple of strong hooks. In the adult stage this worm lives parasitically in the
bladder of frogs. It lays its eggs in the spring, and by thrusting itself partially
out of the frog's body deposits them in the water. The eggs take from six to

A, Dactylocotyle ; B, Anthocotyle (magnified).

FLAT-WORMS.

467

eight weeks to hatch ; and the young worm is an active little animal, swimming

by means of the cilia with which its body is bordered. It differs from the adult by

the presence of the fringe of cilia which extends along the sides of the body from

head to tail, and also by the absence of suckers

at the posterior extremity of the body. The

latter, however, is furnished with eight pairs of

hooks, which are retained in the adult. After

leading a free life for a short time, the larva

attaches itself to the external gills of a tadpole,

and speedily loses its clothing of cilia. When

the gills shrivel with the conversion of the

tadpole into a frog, the larva enters the mouth

of its host, and, passing thence into its intestine,

succeeds in ultimately making its way into

the bladder, where it lives some five or six

years before reaching maturity.

Two-Suckered Group, — Suborder Distomese.

The second division of trematodes is dis-
tinguished by the smaller number of suckers,
the absence of hooks, and the circumstance
that all the members of the group are internal
parasites, laying an immense number of small
eggs ; while in the course of their development
the young are inhabitants of more than one
host. It is evident that parasites living upon

the skin or gills of fish, where they are constantly in danger of being washed
away, have much greater need of sucking-discs and clinging-hooks than those
living within shelter of some internal organ. On the other hand, it is equally

clear that the large number of eggs laid by the
internal forms, which pass through a complicated
metamorphosis, is a means for providing against the
remoteness of the chances of the larvae meeting with
their appropriate hosts. Some of these worms are of
importance, on account of the destruction they bring
upon the hosts they infest. One of the best known
is the liver-fluke {Distomum hepaticum), found in
the mature stage in the livers of sheep. It is about
an inch in length, and nearly half an inch broad.
The hinder portion of its body is flattened and leaf-
like, but the front is thick and conical, and the outer
skin is furnished with many backwardly-directed
•spines. The eggs — of which it has been computed half a million may be laid at a
time — pass into the intestine of the sheep by way of the bile-ducts, and thence make
their way to the exterior. Many of these eggs fall upon dry ground, where they

Polystornum and larva (magnified).

fr

ijver-fluke and larva (enlarged).

468

WORMS.

perish. Some however, in all probability, make their way into water. When this
has taken place, the egg, after two or three weeks, gives birth to a free-swimming,
ciliated, conical embryo, provided with a double eye and rudiments of an excretory

system. By means of its cilia, this embryo swims
rapidly about in search of a particular species of
pond-snail. If it fails in its search, it perishes in
about eight or ten hours ; but, if successful, it proceeds
to bore its way into the soft tissues of the mollusc.
As soon as it has effected an entrance, it loses its cilia
and turns into an oval sac, the sporocyst, The latter
may multiply by fission, but in any case, in its
interior, another organism, called after Redi, its
discoverer, Redia, arises. This bores its way out of
the sporocyst, which closing up again forms another ;
but if too many are developed they may cause the
death of the snail. The Redia is cylindrical in shape,
and has a distinct mouth and stomach, and in the
hinder half of its body there is a pair of bud -like
processes, serving as rudimentary feet. The larva
in this stage takes up its abode in the liver of the
snail, where, in turn, it proceeds to propagate. Its offspring may be a Redia like
itself but more often it has a different form, and has received the name Cercaria.

development OP Distomum
echinatum.

LARVAL FORM OF LIVER-FLUKE (magnified).

It escapes from the parent Redia by an aperture situated near the front end of
its body ; and presents a considerable resemblance to a tadpole, consisting of a long
vibratile tail, and a wide heart-shaped body with a forked intestine, two suckers,

FLAT- WORMS. 469

and a gland on each side of the intestine. These larvae make their way out of the
snail, but instead of seeking a new host swim about for a time and ultimately
settle upon some water-plant, or a blade of grass in a meadow. Here they
enclose themselves in a capsule, and await the chance of being devoured along
with the grass by a sheep. From the stomach of the sheep they make their
way into the bile-ducts, and there develop into the mature stage.

TURBELLARIAN WORMS — Order TURBELLARIA.

Nearly all the worms of this group lead a free life, parasitism amongst them
being the exception. They are found either on the land or in fresh or salt
water, and have received the name Turbellaria, or whirl-worms, from the
whirling eddies of water caused by the lashing of the cilia with which their
unsegmented and flattened bodies are covered. In shape they vary considerably,
being either short and oval, or long and worm-like. The alimentary canal is
almost always well developed, having a distinct mouth, but never a posterior
outlet. There are no special respiratory or circulatory organs, the function of
breathing being performed by the entire surface of the skin. The nervous system
consists of a large double-lobed brain-ganglion, from which, in addition to some
branches passing forwards and outwards to supply the head and eyes, two stout
cords, one on each side of the body, run backwards to supply the tail.

Suborder Rhabdoccela.

This group is characterised by the straight and unbranched intestine.
A fairly well-known member of the suborder is Mesostomum ehrenbergi,
a species about half an inch long, found during spring and summer in ponds and
streams. The generic name refers to the fact that the mouth, with its muscular
gullet, is situated in the middle of the lower surface of the body. Although as
transparent as glass and extremely fragile, it is a swift swimmer, moving quietly

through the water either by , ,

means of its cilia, or by waving
the edges of the exceedingly
flexible body. It feeds upon
fresh-water worms, insects, and
crustaceans, its way of over-
coming its prey being somewhat Mesostomum tetragonum.
curious. The worm converts its

body into a cup-shaped hollow, at the bottom of which the mouth is situated, by
bringing the two ends close together, and turning over the flexible edges in the
same direction. In this manner it envelops its prey, and so deprives it of all
chance of escape. It is stated that this and other species ensnare their prey
by means of slimy threads. Eggs of two kinds are laid ; those found in summer
being soft-shelled, while those of winter are protected by a hard and thick
coat so as to be able to withstand the unfavourable conditions of this season.
An allied species (M. tetragonum) is shown in the accompanying illustration.

47°

WORMS.

Upon the narrow and pointed head are the two little black eye-spots, In the
genus Prostomum the mouth (b) is situated in the middle of the ventral surface,

as in the last, but the slender
and pointed head - end is
provided with a distinct
proboscis (a), which calls
to mind that of the
nemertines, inasmuch as it
is not directly connected
with the mouth, and is
contained in a special sheath.
The posterior end of the
body, on the contrary, is
thick, club - shaped, and
armed with a sharp goad,
which seems to be used as
an organ of defence. The
same illustration shows a
species of the allied genus Vortex, in which the aperture of the mouth is on the
under side, near the front end of the body. This mouth leads into a large oval
gullet, communicating with the long sac-like intestine. The black spot in front
of the mouth is the eye. In Schizostoma, on the contrary, the mouth which is
long and slit-like, is situated in front of the two eyes. Some of the allied genera
lead a parasitic and not a free life. For instance, Anoplodium is found upon
sea-cucumbers, and Graffdla upon marine gastropods.

1, Prostomum-

TREMATODES.

-a, proboscis ; b, mouth. 2, Convoluta.
(Natural size represented by lines. )

3, Vortex.

Schizostoma productum (enlarged 200 times).

Differing in many important points from the typical Rhabdocoela is the
small marine Convoluta, shown in Fig. 2 of the illustration, in which the
alimentary canal, the excretory organs, and the nervous system have dis-
appeared. Imbedded in the solid tissues of some of the species of Convoluta
are large numbers of cells containing chlorophyll, or the green colouring
matter of plants. These cells are probably minute plants (Alga?), which have
taken up their abode parasitically in the worm. In addition to the ordinary
means of reproduction by sexual organs, some of the rhabdoccelans multiply by
division.

FLAT- WORMS.

47i

The accompanying illustration shows one of these worms (Stenostomum
monocelis) in process of giving rise to a second individual. In the upper half of
the figure (0) is the mouth, and (s) the auditory
organ of the parent; the coiled tube (v) being
part of its excretory apparatus, and (e) some
eggs. In the lower half (o) is the mouth, and
(s) the auditory organ of the newly-forming
individual. The division may begin successively
at several places on the body before the last and
oldest bud is attached, so that it results in the
formation of a chain of segments lying one
behind the other.

Suborder Dendrocoela.

The members of this division differ from
the preceding in having the intestinal canal
tree-like, or divided into a number of branches.
The mouth, which is situated on the inner
surface, leads into a muscular and flexible
pharynx, capable of protrusion like a proboscis.
The body is broad and flattened, usually broader
in front than behind, and generally bears a pair
of eyes upon what may be termed the head.
In the genus Polycelis — the species of which
occur in meadows and stagnant water — there
are a large number of eyes, the broad front end of
the body being bordered with from thirty to
fifty of these organs. On the other hand,
Geoplana subterranea, which lives in sandy and
clayey soil, in company with earth-worms, upon
which it feeds, is entirely devoid of organs of
sight. Many members of the group are in-
habitants of the land and fresh water, and are
collectively termed Planarians. These are often
objects of considerable beauty, being both
graceful in movement and decked with various
colours. The two-striped Geodesmus bilineatus,
for instance — which has been found in hothouses
in Europe, where it has been doubtless intro-
duced from the tropics with exotic plants — is a
dull yellowish colour above, but is ornamented
with two reddish brown bands, extending on
each side of the back, and meeting near the
front and hinder end of the body. Another planarian not infrequently introduced
into the conservatories of Europe belongs to the genus Bipalium, this species

SINGLE-EYED TURBELLARIAN, StenOStOmum

(much enlarged).

472

WORMS.

(B. kewense) having been first obtained in the plant houses at Kew. It is a
striking creature, measuring upwards of a foot in length when fully extended, and

c

structure of a dendroccelian (enlarged 5 times).

having the grey colour of its skin relieved by three dark longitudinal bands running
along the back from the head to the tail. It is exceedingly flexible and contractile,
looking sometimes short and stout, and at other times long
and narrow. The head is susceptible of many changes of
form, assuming the shape of a hammer-head or the blade
of a cheese -cutter, and the next moment being tongue-
shaped. The skin is richly supplied with glands, secreting
a sticky slime, by means of which the Bipalium is able to
ascend perpendicular surfaces, and to lower itself from a
high point by letting out a thread of the material. It is said
to feed upon earth-worms, and to propagate by division ; the
tail-end breaking off and growing into a second individual
by acquiring a head, proboscis, and intestine. Land
planarians are abundant in the damp tropical forests of
Ceylon, South America, and Australia ; and a rich population
of allied forms frequents the sea. One of the most striking
of these marine forms is the tufted planarian (Thysanozoum),
represented in the illustration on p. 473. Here the back is
covered with many rows of dark-coloured tufts; the lower surface being pure
white, and the head end furnished with a pair of ear-shaped lappets, in which the
sense of touch appears to be concentrated. The creature is shown clinging to a

SMOOTH POLYCELIS.

a, The animal ; c, The eyes

TWO-STRIPED GEODESMUS

(enlarged twice).

planarian worm, Planaria gonocephala (enlarged).

branch of seaweed, with the head elevated so as to exhibit its lower surface, and
feeling for a new surface of support. Planaria gonocephala, figured above, is one
of the land forms. The general structure of the intestine in all the animals of this
group is shown in the illustration at the top of the page.

DIC YE MID S.
Group of Uncertain Position.

473

To complete our account of the worms, mention must be made of the parasitic
families Orthonectidce and Dicyemidcc, of which the serial position is uncertain.

•™

Rhopalura. A, Male; B, Female.
(Very much enlarged.)

The members of the former inhabit
the body -cavity of certain turbellarian
and nemertine worms and brittle-stars.
They are minute, segmented creatures, scarcely exceeding the twentieth of an inch
in length, and without digestive organs or nervous system, but with the skin
ciliated. The males are smaller than the females, being in the figured Rhopalura
only about half the size of the latter. The Dicyemidce are ciliated, thread-like
parasites, varying in length from about a thirteenth to a fifth of an inch in length,

tufted planarian, Tliysanozoum (enlarged twice).

A DICTEMID (enlarged 20 times).

and living in the kidneys of cuttle-fish. The body consists of a central portion,
composed of a single long, fusiform cell, around which is arranged a series of whiter
cells, partly projecting like papillae from the surface. At the front end the cells of
the external layer form a symmetrical head, by which the parasite attaches itself ;
but there are no distinct nervous, digestive, or muscular organs.

E. I. POCOCK.

CHAPTER XIV.

Jelly-Fish, Corals, and Sea-Anemones, —
Subkingdom CCELENTBRATA.

Few have been able to revel in the exquisite beauty of the southern coral islands,
which through thousands of years have been slowly piled up to the surface of
the water by the coral -animals. The vivid colouring of the fauna in the
lagoons of those marvellous islands is not to be found in European seas, but even
in these less favoured climes, any observant traveller, as his ship passes through
calm water, may notice lovely creatures nearly related to the corals. Who, for
instance, has not seen exquisitely coloured transparent jelly-fish, floating just below
the surface, and propelling themselves by alternately expanding and contracting
their bells ? Or who that has kept a marine aquarium has not admired, as its
greatest ornament, the sea-anemones ? These animals, the corals, the jelly-fish, and
the sea-anemones, constitute the great group known as Ccelenterata. The group
comprises all those creatures in which the internal cavity, corresponding with the
alimentary canal of other animals, is not a closed canal running through the body,
but is commensurate with the whole cavity of the body. Consequently there are
no spaces answering to* the body-cavity of the Vertebrates, between the wall of the
alimentary canal and the outer wall of the body.

A study of the earliest growth of the Coelenterates has shown that their
internal cavities are nothing more than regular radiate outgrowths of the intestine,
and, like the latter, come from the primitive intestine of the larva. The result of
this development is a condition which does not occur elsewhere in the whole animal
kingdom. We have no separate digestive canal, no closed blood vascular system,
and no specialised respiratory apparatus. There is only a system of cavities, all
in open communication with one another, occupying almost every corner of the
body.

Again, the Coelenterates are radiate in structure, that is, when seen from above,
they are typically star-shaped ; and if a Ccelenterate be cut across, every horizontal
section shows a symmetrical arrangement of the parts around a centre. There are
other radiate animals, such as the Echinoderms, but while in these five is the
fundamental number of rays, in the Coelenterates the rays are often far more
numerous, being some multiple of four or six. Again, while the skin of the former
is almost always modified into a skeleton, or is thick like leather, leathery skins are
the exception in the latter. When the Coelenterates do form calcareous skeletal
structures, these are quite different from the tests of the sea-urchins ; and, in all
cases, the anterior end of the body, crowned with one or more circles of tentacles,
remains soft and flower-like. The most highly developed of the free forms, how-

CTENOPHORES.

CTENOPHORES.

475

ever, such as the sea-anemones and the jelly-fish, have no hard skeleton at all, but
are amongst the most delicate and beautiful objects in the realm of living nature.

In spite of the variety of forms to be found, the Coelenterata are almost as
incapable of higher development as the Echinoderms. Like the latter, they have
failed to make any way in fresh water, not to speak of the land. A few free-
swimming jelly-fish, a minute attached polyp, and some degenerate sponges are,
indeed, found in fresh water, but these can hardly be looked upon as successes.
While, at present, it is not easy to connect the Coelenterata with any other group,
inasmuch as they appear to stand without any near relatives among the higher
animals, they have a special interest, since they are considered to represent a stage
in the development of animal life through which all the higher forms have passed.
Some simple form of Coelenterate may have given rise to all the higher animal
forms, the modern Coelenterates — the sea-anemones, corals, etc — being those
descendants of the primitive simple form which have retained the original type of
organisation almost unchanged.

The Ctenophores, — Group Ctenophora.

Although all are agreed that the so-called Ctenophores are members of this
subkingdom, their exact position is not clear. The Ctenophores are glassy,
transparent creatures, either shaped like apples, melons, or Phrygian caps, or else
forming bands, often a yard in length, and thickened at the middle. Several
types are shown in the coloured Plate. The marvellous transparency of all
but one (Beroe) is specially remarkable. They inhabit the open sea, or are driven
by currents and winds near the coast and into harbours. Their position in
the water is usually more or less vertical, the mouth being turned downwards.
The organs from which this group takes its name are the ribs, which either run
from pole to pole, or else only for certain distances along the meridians, which are
often symmetrically arranged. These ribs consist of rows of short transverse
combs, each being formed of a row of cilia. The cilia forming a comb are connected
together at their bases, but are also capable of independent movement. As they
wave to and fro, they constitute what is called a swimming or rowing plate. The
activity of these rows of plates depends upon the will of the animal, which can
move either the plates of a single rib, or all the ribs together ; this latter movement
resulting in slow locomotion in the direction of the apical pole, i.e. the pole turned
away from the mouth. The body is capable of various swift, light, and graceful
movements, for in addition to the rowing plates there are other structures, such as
the oral umbrella and the capturing filaments or tentacles, with their hair-like
branches. These tentacles, which are attached like arms at the sides, are capable
of erection, or of withdrawal into pockets. There is great variety in the develop-
ment of these accessory organs of locomotion. For instance, the Cydippidoi
have only arms, which, with their branches, serve for capturing food as well as
for steering. In other orders, vertical, oar-like, dermal folds stand out from the
body, by means of which the movements become more rapid and energetic. Some
species of Eucharis, by suddenly shutting up the oral umbrella, can jerk themselves
forward ; and when successive jerks of this sort cause the body to move with

476

CCELENTERA TES.

greater speed than usual, the arms are withdrawn into their pockets or stretched
backward like a rudder. This power of free locomotion necessitates some
regulating organ, so that the desired direction or position of the body may be
maintained. Such an organ exists at the apical pole of the body, and may be
described as consisting of a small weight borne on springs, by which the oscillations
of the body or deviations from the line of movement can be instantly felt.

The ventrally placed mouth is like a large slit between the folds of the
umbrella, and leads into a stomach which is either tubular or flattened. The food is
digested in this stomach, the indigestible parts, mixed with mucus, being again

ejected through the mouth. The upper
end of the stomach is in direct com-
munication with a funnel-shaped space
of variable width. From this funnel-
like cavity canals arise, which branch
and run below the outer surface, follow-
ing the lines of the ribs. This funnel
further possesses an aperture of its own,
opening on the exterior, in the region
of the apical pole. Within the funnel is
found a fluid substance containing par-
ticles of the food -pulp drawn in from
the stomach, but consisting chiefly of
water, taken in voluntarily; this fluid
being kept in motion by ciliary action
through the canal -system. Although
water is also sometimes taken in through
the proper apical aperture of the funnel,
this aperture seems principally to serve
for the ejection of the fluid when of no
further use. It is then also mixed with waste matters from the body. Stinging-
cells, such as occur in the next group, have as yet been found in only one species
of Ctenophore (Haeckelia rubra), and then only in small numbers. Instead of
stinging-cells, the Ctenophores have adhesive cells, or small hemispherical knobs
found on the tentacles or capturing filaments ; these being provided with elastic,
spirally-coiled stalks, but containing no poison. These knobs are beset with sticky
globules, to which small animals, such as minute crustaceans easily become attached.
If the prey attempt to escape, the spiral thread by which the knobs are attached
becomes stretched. When the thread is withdrawn, it more or less entangles the
victim, arid, being like the knob, provided with a great number of sticky particles,
renders escape impossible. These structures are very different from stinging-cells,
which are useless to an animal after having been once employed. An adhesive
cell or knob can act apparently any number of times, being each time drawn back
by the spiral thread to its former position.

Ctenophores feed upon all kinds of small pelagic animals, especially
Crustaceans, while they themselves fall a prey to the disc-shaped jelly-fish and
sea-anemones. Ctenophores may continue to grow, if uninjured, almost indefinitely,

cydippe (nat. size).

CTENOPHORES. 477

or as long as life lasts. Storms, however, destroy them. The largest specimens
are, as a rule, found in waters sheltered from the wind. They are to be seen
throughout the whole year, but are most plentiful during the spring months, and
become rarer towards summer, when some species, such as the Venus' girdle, almost
completely disappear. In the early autumn, however, great swarms appear,
especially of Cestus and Beroe. After a spring of active fertility, the larvae, at the
beginning of the hot months, sink down to greater depths, where they grow into
adults, and come to the surface again in swarms in autumn.

Insignificant as these delicate creatures may appear, they delight the eye,
both while living and after death, by their luminosity. This is principally
displayed in the walls of the canals below the ribs. It is a curious fact, and one
unique as regards luminous marine animals, that Ctenophora, after being exposed
for only a short time to the light of the sun or the moon, or to artificial light, when
suddenly brought into a dark room, are incapable of giving light. All man is of
opinion that the Beroidm and their broods must be regarded as the principal
source of marine phosphoresence on the English coast.

The Ctenophora are hermaphrodite ; sexually mature animals of many species
being found throughout the whole year, while others occur only in spring, summer,
or winter. The young pass through a metamorphosis, or have larval stages which
precede the definite form. In at least one species {Eucharis multicornis) sexually
mature larvae, or larvae which are capable of reproduction as such, also occur ; these,
when completely developed, become once more capable of reproduction as adults ; —
a method of multiplication which has been called dissogony.

The most interesting, if not the most beautiful, of the Ctenophora are the
Beroidce, — shown in the coloured Plate, — which resemble Phrygian caps in shape.
In section, they are oval ; the mouth is wide, and they have no capturing filaments
or tentacles, and therefore no adhesive cells. They attain a size of 8 inches, and are
of a delicate red colour, which appears marbled. This appearance is due to the
branching of the eight principal canals above described, the ramifications forming
a network. Beroe for skalia, shown in the Plate, is found in the Mediterranean. The
Beroidce are carnivorous, feeding on their own relations of other genera. On one
occasion, a large EucJmris was placed in a basin with a Beroe forskalia, not half
its size, in a fasting condition. The latter, attracted by its wonted food, began
swimming round the Eucharis in large circles, with wide open mouth. On
approaching its victim, it darted at it, and seized it. The swimming-plates of the
Eucharis beat helplessly, when, to the astonishment of the observers, this large
creature was completely mastered by the Beroe, which in less than a quarter of an
hour succeeded in swallowing its victim, and, distended like a balloon, lay at the
bottom digesting it.

The Cydippida? are conical, or barrel-shaped, with the ribs uniformly developed,
and two opposite tentacles, one on each side. The beautiful creature figured in the
Plate is Hormiphora plumosa from the Mediterranean. The remarkable Venus'
girdle {Cestus veneris), shown in the annexed illustration, is so called because the
body is lengthened, out sideways like a ribbon, so that the mouth is found on the
under edge of the ribbon half-way along it. This girdle-shaped, transparent
creature, iridescent in the sunshine, is a dazzling sight. The ribbon is edged with

478

CCELENTERA TES.

cilia, corresponding with the ciliated combs of the body proper. An additional
charm is added to this beautiful form by its lively graceful movements, the ribbon
assuming all possible curves. If roughly touched, it rolls up spirally, beginning
at one end. When undisturbed, its ribbon -like outgrowths are sometimes
stretched out, sometimes more or less rolled up, or else the one is rolled up and the
other extended. It can, like other Ctenophora, keep itself in motion by the mere
play of its cilia, but it also uses the undulating movements of its ribbon-like
body. The transformation of the larva after leaving the egg is complicated. The

venus' girdle (J nat. size).

young larva is shaped like a balloon, and possesses two principal tentacles provided
with lateral filaments ; it has further, on each rib, four to five swimming-plates.
At this stage this larva resembles the adults of some other species of Ctenophora,
and only by degrees, after passing through many other stages, assumes the form
of the girdle.

Stinging Series, — Group Cnidaria.

The Cnidaria, or stinging Ccelenterates, which comprise the sea-anemones,
corals, jelly-fish, and the little hydra of English ponds, receive their name from the
so-called stinging-capsules, found in their skin, which may be regarded as the
homologues of the adhesive cells of the Ctenophores. Before describing these
offensive and defensive weapons, it is necessary to obtain some idea of the animals
which use them, these Cnidarians having departed less from the simple Ccelenterate
type than have the Ctenophora, in which this type is much disguised. Imagine,

CNIDARIANS. 479

then, a long footless stocking, sewn up at each end. By thrusting one- half of this
stocking into the other half, there would be obtained a long bag with a double
wall. Suppose this bag fixed by its blind end to the ground, while the open
mouth-end stood up in the air, to catch anything that fell into it, and then suppose
that, close round the mouth, the double wall grew out into arms or tentacles, which
could catch anything passing and draw it into the mouth, then we should have a
structure somewhat resembling the fundamental form of the Ccelenterata. But it
must further be supposed that the two woollen walls of the stocking are replaced
by two layers of living cells, so that the outer one forms the skin, which is armed
with the stinging-cells, while the cells of the inner layer are hungry creatures
waiting to digest anything digestible which comes down into the bag. This is still
not enough, as the whole animal must be able to move its tentacles, and to stretch
or contract its body ; so that between the layers there is a special gelatinous layer
in which run muscle and nerve fibres. Further, in order that the tentacles, when
they seize a passing animal, may have no trouble with it, but may be able to bring
it to the mouth as easily as possible, they are thickly covered with batteries of
stinging-cells. But how, it may be asked, can we get the beautiful bell-shaped
jelly-fish from such a creature ? The imaginary animal just described was fixed
to the bottom of the sea, or to weeds and stones under water, and here it would
grow. But there is a law of life that, after a certain size has been reached, further
growth does not add to the animal's stature, but takes the form of buds, which
may either be cast off as eggs to hatch and develop elsewhere, or may remain
attached to and branching out from the parent animal. Both these processes take
place in the simple Cnidarians. Some branch and rebranch to form beautiful
trees, or stocks, made up of living animals. Now if all these animals were to drop
eggs which fell to the ground to grow up around the parent stock, so fast would
they grow that they would soon be killing one another through overcrowding.
Hence it has come to pass that in many forms only a certain number of the
animals forming a stock produce eggs, and these are able to break away and swim
off with their load of eggs, to drop them far away. In this way, swimming-bells
have been produced, originally only as carriers for scattering eggs broadcast, just
as many trees have arrangements for scattering seeds as far as possible from the
parent stem. From this beginning, all the race of jelly-fish appear to have sprung.
The free-swimming life offered new fields for catching food. Myriads of small
creatures swim near the surface of the water ; the Cnidarian fixed to the bottom
of the sea may stretch its arms in vain for these, while the free-swimming bell
can go amongst them and follow them along the surface currents, feeding as it
goes. Hence, while the eggs of many jelly-fish when dropped develop first into
fixed tree-like stocks, which, when grown, let loose another swarm of jelly-fish,
the eggs of others, as if to save time as it were, and impatient of the fixed tree-like
stage, hatch out at once as young jelly-fish, which rise at one bound to all the free-
swimming privileges of their immediate parents.

The former process is termed alternation of generations ; the egg producing a
stock, which is one generation, the stock producing a jelly-fish, which is a second;
and these two alternating. In the latter case, when a jelly-fish produces a jelly-
fish, one generation — the stock — has been suppressed. This is important, since there

480

CCELENTERA TES.

is evidence that this alternation of generations was, and indeed still is, widely
spread in both the animal and the vegetable kingdoms. It is however, as a rule,

suppressed, as animals rise in the scale of
organisation. The Ctenophora are a highly
developed group in which this alternation
of generations has been suppressed.

One word as to the changes neces-
sary to turn the simple Cnidarian above-
described into a bell or umbrella - like
jelly-fish. The principal change is in the
gelatinous layer between the outer skin-
wall and the inner stomach or digesting
layer. This middle layer develops into
an enormous mass of glassy jelly of such
a shape that, instead of the body being
long from the mouth (oral pole) to the
bottom of the sac (aboral pole), the animal
is umbrella-like, the mouth being under
the bell, while the top of the bell corre-
sponds with the old base by which the
parent polyp was attached to the ground.
Before taking the principal forms
assumed by the Cnidaria, and briefly
describing their relation to one another,
the stinging - cells and batteries claim
attention. These cells, though all micro-
scopical, vary considerably in size, with-
out their structure being essentially
affected. The surface protoplasm of the
cell is modified into a tolerably firm shell,
enclosing an oval or cylindrical vesicle.
Closely associated with this structure is
a pointed process, standing up far above
the level of the skin, known as the
cnidocil. Within the vesicle is found,
either spirally rolled or in an irregular
tangle, a long filament, or hollow tube,
which is a prolongation of the vesicle, but
turned outside in. This tube, which is
more than twenty times as long as the
cell, is pointed at the tip, and almost up
to the tip beset with two rows of fine,
spirally-arranged, barbed hooks. When
the cnidocil is touched or irritated, this

STINGING CAPSULES. . . , ,, i , r> ji V •

1 and 2, With ratracted filament; 3, Partly protruded; filament 1S Violently shot forth, being
4 Fully protruded. (Highly magnified.) turned inside out like the finger ot a glove.

JELLY-FISH] ETC. 4Si

So long as the thread remains rolled up within the vesicle, the barbed hooks
are, of course, in the tube, but when it is shot out, they come on the outside.
The rolled-up thread appears to be filled with some poisonous substance, which,
when the tube is shot out, is ejected over the spot where the point strikes
and wounds. It has been asserted that in many, probably in all, Coelenterates,
muscle and nerve elements occur below, and are associated with, the stinging-
cells. The action of these stinging-cells is perhaps as follows. The cnidocil is
touched by some passing object, and conveys the stimulus which leads to the
violent contraction of the distended vesicle. This forces out the tube which is
lying in it, in the manner described. A simple touch is, however, not enough to
cause the cell to be discharged, otherwise such discharge would take place when
the animal knocks against a stone, or when the tentacles, being withdrawn, touch
the body. We must assume that the Cnidaria are able to distinguish between the
various stimuli received from contact with other bodies. The stinging-cells are
very often grouped together to form so-called stinging-batteries of various sizes.
Dr. Mobius writes that as soon as the capturing arm touches the passing victim,
the long filaments are shot out of the stinging-capsules, penetrate or adhere
to the animal and detain it. Unless the prey is stronger than its attacker, it
cannot escape. New filaments are being continually shot out at it as it is slowly
drawn in towards the mouth ; even within the body-cavity similar stinging-cells
are found in the skin. The greater the struggle, the larger the number of capsules
discharged, in order to hold the prey.

The Jelly-Fish axd their Allies, — Class Polypomedusse.
Order Siphonophora.

We have already described the swimming-bells of the jelly-fish as the highest
development of the stinging group. The Siphonophora, as represented by the
Portuguese man-of-war, are, in their turn, the highest development of the
swimming-bells. They are, in fact, colonies of bells, joined together in almost
every possible way, and showing extraordinary modifications of individuals in
the interests of a division of labour. For instance, some of the bells do nothing
but row the colony along, others feed the colony, others are guards, and yet others
produce the eggs. As our first example of the group, we may take the creature
known as Physophora, which consists of a long tube or central axis, surmounted
by an individual which is nothing but an air- vesicle for holding the colony in an
upright or a sloping position in the water. Below the air-vesicle come two rows
of bells, which bring about by their contractions the movement of the whole
colony. These rowing-bells force the water out of their cavities, and thus propel
the colony. Below these, again, comes a circle of extremely mobile tentacles,
which may perhaps be the tentacles of vanished bells. Among these tentacles
are hollow structures, open at the end, which are the feeding-bells, now reduced
to sucking-tubes, or stomachs, each of which endeavours to seize and digest for
itself whatever in the shape of food (chiefly small crustaceans) is brought to it by
the long capturing filaments and their branches, armed with stinging organs.
The colourless blood and nutritive fluid prepared by these two stomachs serve

vol. vi. — 31

482

CCELENTERA TES.

for the nourishment of the whole colony, and are carried to the various parts
through the axial tube above mentioned. In the illustration, which has been
chosen on account of its comparative simplicity, no reproductive or egg-bearing
bells are shown. When present in the Physophora, these appear like clusters of
grapes ; in other genera they are capsules ; in others, again, they may be actual

swimming- bells, which become detached, and lead an
independent life. This fact is of importance in helping
us to understand this complicated organism. It shows
that the Physophora is not a single animal, but a stock
or colony. Of this there is evidence in the rowing-bells,
as well as in the two, three, four, or more sucking-tubes,
with distinct mouths and stomachs. And, lastly, we have
the reproduction brought about, in some cases, by detached
jellyfish-like individuals. All the parts of the organism
form a whole in a physiological sense ; they belong to
one life, and many are so modified as no longer to appear
as individuals. But, on the other hand, some of them
are fairly independent, and, when they take the form of
medusae, they are so highly developed that their individu-
ality is at once manifest. We must, therefore, regard
a Siphonophore as a colony of highly - modified in-
dividuals, which — owing to the fact that these individuals
differ greatly in form and function — constitute what is
termed a " polymorphous colony."

One of the most beautiful and most dangerous of
the Coelenterata belongs to the Siphonophora. This is
the so-called Portuguese man-of-war (Physalia), several
species of which are found in the southern seas. The
air-bladder at the top of the stem is a large, oval vesicle,
which projects above the surface, lying horizontally on
the water. It is drawn out into two points at opposite
poles. A comb runs lengthwise and somewhat slantingly
along the top of it. From its lower side, nutritive polyps,
feelers on which the genital products develop, and very
long tentacles hang down side by side below the surface
of the water. Another strikingly beautiful species found
in the Mediterranean is P. pelagica. Lesson writes that
these creatures " shimmer with the most splendid colouring.
The air-bladder and its comb look like molten silver, adorned with light blue,
violet, and purple. The small thickenings on the keel of the comb are of a vivid
carmine, while the appendages are of a wonderful, delicate, ultramarine blue."
The English name is happy, as it indicates the latitude in which the traveller
from Europe first meets with it, its ship-like appearance on the surface of the
water, where it uses its comb as a sail to catch the wind, and its ample provision
of weapons. The tentacles of the Physalia are stiff with batteries of stinging-
capsules, and those who are careless enough to touch them will repent. Meyen

Physophora, with two rows
of swimming bells (nat. size).

JELLY-FISH, ETC

483

relates that during the first voyage round the world made by the ship Princess
Louise, a sailor jumped into the sea to capture a large Physalia. As he seized it,
the animal enveloped him in its long filaments, stinging him so terribly that he
cried out for help, and was hardly able to swim back to the ship to let himself be
hoisted up. Severe inflammation and fever followed, and his life was for some
time despaired of.

During the Challenger expedition, deep-sea Siphonophora of a remarkable
kind were brought to light. The most interesting belonged to a new family, the
Auronectidce. The colony, instead of being a long string of individuals, is here
thickened and shortened so as to be oval or round. It consists of a hard,
cartilaginous mass, traversed by a close system of branching canals. The upper
part of this mass is a large, round, hollow air-bladder (p in the figure). This
pneumatophore is surrounded by a
circle of large, round swimming-bells
(n), one of which (I) is modified in
a remarkable way. It is not, like
the rest, quite hollow, but is traversed
by a narrow canal attached to its
walls by strands of gelatinous tissue.
The free end of the canal opens out-
ward through a short tube, while its
attached end enters the great
bladder of the pneumatophore. This
specially modified rowing -bell has
been called the aurophore, since it
appears to regulate the quantity of
air in the air-bladder. In order to
sink to a greater depth, the Stephalia
has only to contract its pneumato-
phore, discharging the air through
the lateral canal. When the animal
rises, the aurophore probably secretes a gas which fills the pneumatophore again.
The lower end of the colony is occupied by a^ large feeding or nutritive polyp,
and at its sides there are several rows of smaller nutritive polyps (s), each of
which, at its base, carries a capturing filament (t), and at its side grape -like
clusters of reproductive bodies.

The Siphonophora, as a rule, require frequent changes of depth. It does not
appear that exclusively deep-sea forms are to be found in the Mediterranean, but
that all Siphonophora under certain circumstances and at certain seasons appear
at the surface. Many pass through their larval development at a great depth,
and the young Physophora larvse found at the surface in the spring descend to
greater depths at the commencement of summer, and only return, when their
metamorphoses are complete, to develop into sexually mature animals. In the
Physophoridce we had the different individuals in a long series. In the Auronectidce
we found them arranged in a compact mass; and, lastly, in the Velellidce, the
body is flattened out to a disc, which is traversed by a system of canals. On

Stephalia (nat. size).

4S4 CCELENTERATES.

this disc lies the similarly shaped pneumatophore, which is also traversed by
concentrically arranged canals opening outwards. The polyps hang on the lower
side of the cartilaginous disc, a large nutritive polyp occupying the centre, surrounded
by concentric circles of smaller nutritive polyps. As in the Auronectidce, these
polyps carry at their bases genital clusters, but no capturing filaments. The
tentacles are arranged round the margin of the disc, and are very short. The
genus Velella, one species of which is frequently found in the Mediterranean, has
an irregular oval disc, surmounted by a sloping comb, which acts as a sail. These
animals, which are of a deep indigo colour, are often found in swarms.

Order Hydromedusae.

Having considered the complicated colonies of swimming-polyps constituting
a Siphonophore, the individuals of which have each been simplified for the
performance of a limited number of duties, we turn to the solitary swimming-
bells, each one of which forms an individual competent to perform all the many
functions required in its struggle for existence. There are hosts of these bells, of
almost all sizes, some being large and beautiful, but dangerous to touch, while
others are quite minute creatures, which have to be examined under the microscope.
In regard to these swimming medusae, it has been already mentioned that they
were primitively individuals broken loose for a free-swimming life in the open
sea from a stock attached to the ground at the bottom. The eggs of some of these
forms have now given up passing through the attached stage, and hatch out at
once as young medusae. Now, examination has shown that this host must be
divided into two groups, having remarkable differences, the one being called the
Hydromedusae, and the other the Scyphomedusae. The two came from two
different kinds of attached stocks, and consequently, as free-swimming animals, in
spite of their general resemblance to one another as jelly-fish, each has organs
which the other wants. Taking the Hydromedusae first, as closest to the Siphono-
phora, we describe a few in detail, in order to give a clearer idea of the alternation
of generations.

Among the Hydromedusae there are the following different life -histories.
Beginning with the highest, we have — (1) jelly-fish alone, the eggs of which have
given up forming stocks, but hatch out jelly-fish ; (2) jelly-fish, the eggs of which
still form stocks, some individuals of which swim away as jelly-fish ; (3) stocks in
which the sexual individuals do not swim away as jelly-fish. We need not here
describe any of the medusae in detail, since the much larger jelly-fish of the
Scyphomedusae will claim our attention presently, but two remarkable forms, which
have taken to creeping on the ground, deserve attention. In Dalmatia, on seaweed,
a delicate, pale object can often be discerned with a magnify ing-glass creeping
laboriously about on its long arms. If detached from the seaweed, it falls to the
bottom, as it is unable to swim. In each point of its structure this animal is a
medusa, related to the genus Eleutheria, or Cladonema, but still further removed
from the ordinary medusa in one respect, since the Cladonema alternately swims
and creeps. This creeping medusa (Clavatella prolifera) has six arms, the tips of
which are provided with true suckers. On these it walks, as on stilts, while from

JELLY-FISH, ETC

485

each arm a short stalk rises, the swollen end of whicli is beset with stinging-
capsules. The very extensile mouth-tube moves about tentatively, and easily
seizes upon the small crustaceans to be found upon the seaweed. Just above the
base of each arm lies a horseshoe-shaped eye-spot containing a well-developed
lens, but so far the nerve belonging to a true eye has not been discovered.
Somewhat higher up, between every two arms, a bud is to be found. None of the

Clavatella (a, magnified ; b, nat. size).

specimens of a certain size examined in May were without their six buds, these
being at such different stages of development that their gradual growth could be
clearly traced. On the riper buds the rudiments of a second generation of buds
were to be seen. Multiplication by budding has been observed in other medusae,
and it is from such budding medusoid colonies that we may perhaps deduce the
remarkable swimming colonies of the Siphonophora. As a rule, however, all
medusae multiply sexually by means of fertilised eggs ; even the Clavatella at
other seasons lays eggs.

Creeping medusae are also found in deep seas, although their presence at great
depths would hardly be expected. Haeckel remarks that " few animals appear
less suited for deep-sea life than
the medusae, with their soft,
mucilaginous, watery bodies,
and their singular methods of
swimming ; nevertheless, a few
species sink down to great
depths." One of the most
interesting forms adapted for
deep - sea life is the Pedis
antarctica, belonging to the
family of the Pectinidw. This
animal is remarkable for its Pedis (nat. size),

sucker- tentacles, which stand

in numbers round the margin of the firm cartilaginous disc (these in the illustra-
tion are represented in a contracted condition). These tentacles bear a great

486

CCELENTERA TES.

resemblance to the tube-feet of the star-fishes, being very elastic and contractile,
and carrying a sucker at the tip. They are used in the living state for attachment,
and for creeping in the manner of a star-fish. The disc of Pedis is about H
inches in diameter.

Of the forms among which the reproductive individuals swim away as jelly-
fish, we may take as an example Corymorpha nutans. In this creature, between
the five individuals grouped together in the illustration, five small creatures, each
provided with a filamentous appendage, are to be seen swimming, which are the
medusae belonging to this animal. Each egg of these minute medusae, which are
no larger than in the illustration, develops into a ciliated larva, which, sinking to

Corymorpha, with detached medusa.

the bottom, grows into an attached Corymorpha. The illustration shows these
animals, which in the polyp form are always single, of the natural size. Unlike
most animals of this sort, they do not attach themselves to seaweed or stones, but
live on fine sand, into which they sink the posterior end of the stem. Numerous
thread-like appendages of this buried part penetrate the sand in all directions,
thus firmly attaching the animal. The mouth at the anterior end is encircled by
tentacles, a second circle of tentacles surrounding the widened part of the body
which contains the stomach. Immediately above this latter circle, the buds stand
in clusters; in summer they are found in all stages of development, and even
while attached to their stalks assume the complete structure of a medusa. They
move their umbrellas actively, break loose, and thus complete the circle of develop-

JELLY-FISH, ETC

487

merit or alternation of generations. Bougainvillea ramosa is another form in
which, owing to the stock being branched, the division of labour is even more
clearly seen ; some of the individuals are feeding and some are reproductive, these
latter turning into swimming-bells, and breaking loose. Both these forms are
small, as indeed are the great majority of the hydroid stocks, but whole forests
of hydroid-polyp stocks may be seen on the reefs in the Pelew Islands, almost as
tall as a man, and with roots three or four inches in diameter. A bather, entering
such a forest, is terribly stung, the pain lasting for hours. A solitary form
(Monocavlus imperator) — the upper portion of which is here figured — nearly related
to Corymorpha, and
found in the Northern
Pacific, attains still
larger proportions.
These animals, brought
up during the Chal-
lenger expedition from
a great depth, were
more than two yards
in length, with a pro-
portionate diameter.

As examples of
stocks of which the re-
productive individuals
do not swim away as
jelly-fish, we may select
the pretty, feathered,
plant - like creatures
found along the sea-
shore, which are often
thought to be plants
but are really animal colonies, well-known types being Sertularia and Plumularia.
In these cases, in addition to the nutritive individuals, there are the egg-bearing
individuals which never turn into free-swimming medusae. In saying this, it must
be left undecided whether these colonies are degenerate, that is, were once capable of
producing medusae, but have now lost the power ; or whether they are in a lower
stage of development, above which they have never risen. One small form which is
not branched and feathered is Hydractinia echinata, found in the North Sea and
on the English and Norwegian coasts, where it attaches itself to gastropod shells,
inhabited by hermit-crabs. The polyp probably profits by changes of place for
feeding, or else for some other reason adapts itself to the restless life of the crab.
The part of the stock common to all the individuals is the skin-like portion which
adheres to the surface of the shell or other object to which it is attached. This
skin is raised up into spiny prominences, as shown in the figure on p. 488. A horny
layer occurs in this integument, similar to that of which the single tubes consist.
The nutritive canals running down the stems of the polyps are continued into
this membrane, promoting its life and growth. In such a stock there are never

Monocavlus, upper third (much reduced).

CCELENTERA TES.

more than two kinds of individuals; namely, the nutritive individuals, dis-
tinguished by their long tentacles, mouths, and digestive cavities ; and the
reproductive individuals, male or female. These latter have no mouths, and are
supplied with food through the system of canals running to them from the
nutritive individuals. These reproductive individuals, instead of tentacles, carry

at their tips a circle of stinging-
batteries for the protection of
their eggs, which are enclosed in
capsules clustered together round
the stalk a little way below the
tips. The ciliated larvae emerg-
ing from the eggs swim away,
and eventually become attached
and found new colonies. The
egg -capsules in no way recall
medusae, but all medusse which
pass through a polyp-like inter-
mediate stage also pass through
the simple capsule stage.

Two more of the Hydroid
stocks are worth mention, since
they secrete masses of carbonate
of lime out of which the animals
protrude like corals, which indeed
they were thought to be. This
error was made because only the
massive skeletons of the Hydro-
corallia — as they are called — and
not the living animals were
known. Instead of the horny,
often delicately branching in-
tegumentary skeleton usually
found in the Hydroid polyp
stock, that of the Hydrocorallia
contains ninety-seven per cent,
of carbonate of lime, and forms
rough, solid-looking masses, with
lobed processes or bosses like
those figured on p. 490, or else
(Stylasteridce) branches, like the precious coral of commerce. The whole surface
can be seen even with the naked eye, but still better with a lens, to be covered
with small pore-like apertures. Closer examination shows that these are of two
sizes, a larger central pore being surrounded by an irregular circle of from five
to eight smaller ones. The mass of the colony is traversed by an irregular
system of numerous branching canals of different sizes. In vertical section,
indistinct layers can be seen running almost parallel with the outer surface.

group of a female stock of Hydractinia echinata.
a, Nutritive individuals ; b, Female individuals. (Enlarged. )

JELLY-FISH, ETC.

489

These form the floors of the polyp-cavities. Only in the outermost layer of tho
stock is there life, the inner mass being composed of dead skeleton. In this
living layer there is a close network of soft branching tubes, from which rise the
small polyps, the bases of which are connected together by this network. The
polyps lie in cup-like depressions, and, when undisturbed, project outward through
the pores, retreating instantly at the slightest disturbance. The polyps, like the
pores, are of two sorts. Those inhabiting the larger pores are short and thick,
with four short tentacles, resembling stalked globules, surrounding a comparatively
spacious mouth. The polyps protruding from the more numerous smaller pores,
which surround the large ones, are much longer and have no mouths. Each of
these ends in a simple knob, below which, at intervals, and generally alternately
on one side and the other, short simple branches are given off. The central
polyp remains quite still, but those which surround it are constantly in undulating
motion, often bending down to the mouth of the central polyp, which they appear

stock ok Hydractinia on a shell op the whelk inhabited by a

HERMIT-CRAB (liat. size).

to be feeding. Here, again, there is division of labour in an animal colony, the
larger central polyp provided with a mouth being the feeding individual, while
the mouthless nutritive individuals catch the prey. The smaller polyps also
probably defend the colony, being far better armed with stinging-capsules than
the larger polyp. The knobs with which the tentacles end are stinging-batteries.
The manner of reproduction of the Hydrocorallia — which are tropical animals and
assist in building up the coral-islands — is not yet known. They grow upon rocks
or dead corals, often covering the skeletons of sea-fans (Gorgoniidw), and are even
found in the Bermudas on old bottles thrown into the sea. In the latter case the
lower side of the stock is quite smooth as if polished, and reproduces exactly the
surface of the glass with all its markings.

There are two families of these Hydrocorallia, as they are called, namely, the
Milleporidce and the Stylasteridw. They are of great interest as illustrating the
marvellous adaptability of living forms. While the true corals, which are polyp-
colonies somewhat differently organised from these hydropolyps, secrete great
masses of solid rock, we find two small families of minute hydropolyps also

49°

CCELENTERA TES.

building up hard coral-stocks. This phenomenon is called convergence ; two
different kinds of animals, starting from different points, become adapted to
similar conditions of life, and eventually come superficially to resemble one
another. Just as these hydropolyps forming coral were long thought to be true
corals, so many other animals have, on account of their resemblance, been classed
together which are now known to belong to different groups.

MILLEPORA.

A, Part of a stock with the polyps withdrawn (slightly magnified) ; B, Five peripheral nutritive individuals
round a central feeding individual (highly magnified).

Fresh-Water Two other Hydroid polyps which live in fresh water, while

Forms. aJi £ne rest are marine, deserve mention. Of these, Cordilophora
lacustris forms branched trees from one to three inches high, rising from a net-
work of roots attached to stones, wood, mussel-shells, etc. The whole stock — except
the club-shaped heads of the individual polyps, which are provided with proboscis-
like mouths and irregularly-branched thread-like arms — is covered with a delicate
horny envelope. In these stocks, which are of a red-grey colour, the sexes are
separate. Until the middle of the present century, the Cordilophora had only
been met with in brackish water on the coasts of Europe and of North America.
After that it appeared from time to time in the lower courses of rivers, such as
the Thames, the Elbe, etc., and now it has found its way far inland both in the
Old and New Worlds. It occurs in the Saale, near Halle, and is specially plentiful
in the slightly brackish lake of Eisleben. In Hamburg it has in some places
invaded the water-pipes supplying the city, developing in them to such a degree
as actually to stop them up. This history of the migration of Cordilophora is
instructive in helping us to understand the rise of at least a part of the fresh-
water fauna. In this case, within our own experience, an animal inhabiting
brackish water has in a few years become so adapted for living in fresh water
as to be considered altogether a fresh- water form, without the least apparent
change in its organisation. Whether a change in organisation would not

JELLY-FISH, ETC.

491

gradually take place in the course of many years is, of course, another question,
which for the present is unanswerable.

In the Hydra we have a hydropolyp much better known and much more
specially adapted to its habitat than the Cordilophora. These hydras, which are
from one-eighth to one-third of an inch in length, form simple stocks of one or two
branches, and as often as not are found single. They almost exactly resemble in
form those polyps of the Hydr actinia which are provided with a circle of tentacles.
The water of stagnant pools or ponds in which water-plants are abundant will
almost always yield one of the three species of the fresh-water hydra, if the water-
plants be left undisturbed in a vessel. The little creatures often leave the weed and
attach themselves to the sides of the vessel, where they can be examined with a lens.
When undisturbed, the polyps begin to extend
and spread out their six or eight tentacles
like fine threads. Small creatures, coming in
contact with these tentacles, remain attached
to them, caught and held by the stinging-
threads, whereupon the tentacle contracts,
bringing the prey to the mouth, which is
capable of great extension. Besides the large
stinging-cells which shoot out long poisonous
threads, paralysing and holding fast the small
creatures that happen to come too near, the
hydra also possesses a smaller kind of cells
with smooth threads which are not ejected by
the stimulus that leads to the ejection of the
long threads. Jickeli, who closely investigated
this matter, came to the conclusion that the
small cells were modified for an entirely dif-
ferent function. However small the little
crustaceans paralysed by the hydra may appear to us, relatively to the hydra
they are enormous, and, on being stung, would sink heavily to the bottom.
Jickeli's observations led him to think that the smaller capsules act as buoys to
neutralise the action of gravitation. Indeed, when we remember how far removed
tentacles are from being hands, we can understand how much more easily a victim
could be got into the mouth if it floated helplessly near, than if it tended at every
moment to sink like a stone. The hydra usually multiplies by means of buds
which grow out of the body. The offspring often remains attached to the mother
until it, in its turn, has given rise to one or two buds. Single eggs, however, develop
from time to time in the body- wall beneath capsule or wart-like prominences.

The astonishment of the naturalist Trembley, when he discovered that a
hydra cut in pieces was not destroyed, but that the pieces were capable of
developing into new individuals, was great. He thought that if the hydras were
plants, pieces cut from them would, like young shoots, be capable of further
growth. But he had, meantime, come to the conclusion that they were animals,
and according to the ideas of the time it was an unheard-of thing that new
individuals could grow from cut-off pieces. And thus commenced his experiments

HYDRA MONSTER, ARTIFICIALLY PRODUCED

(5 times nat. size).

492

CCELENTERA TES.

of cutting up hydras, which excited the liveliest interest among naturalists
in the middle of last century.

The hydra is also remarkable on account of its capacity for regenerating
lost parts of the body. Thousands of hydras have been cut up in all possible
ways, grotesque monsters being produced of which drawings were made. Trembley
also made attempts to turn the hydra inside out, like the finger of a glove.
His first experiments of this sort with fasting animals were not successful, but
he succeeded with others which had been well-fed. Animals thus treated often
succeeded in returning to their natural condition.

The formation of buds was watched with care by Rosel, who did not fail to
notice that the digestive cavity of the young polyps, growing out at various parts
of the parent animal, even when provided with functional mouths and arms of their
own, still remained in open communication with the digestive cavity of the parent.

Order Scyphomedus^e.

In the Scyphomedusae we again have free-swimmingjelly-fish, stocks developing

into jelly-fish, and persistent stocks which never
form jelly-fish. Whereas in all the Hydromedusae
the mouth opens directly into the stomach, in the
Scyphomedusae, and their attached and related
forms, the skin round the mouth has been drawn in
to form a tube which opens some way down into
the stomach; the drawing-in of this mouth-tube, or
oesophagus, having led to the formation of ridges
on the wall of the stomach, which hold the inner end
of the tube in place, as shown in the illustration of
Monoxenia, on p. 496. Although this does not ap-
pear important, it indicates a higher specialisation.
Taking first the free-swimmingjelly-fish, the
larger and more characteristic forms are distin-
guished by their delicate colouring. The yellow
and yellowish red Chrysaora ocellata are seen
floating past in thousands off the southern coast
of Norway. The western harbours of the Baltic
Sea, after continuous northerly winds, are often
filled with whole banks of the blue Aurelia
aurita, and the splendid Rhizostoma are con-
stantly to be met with in the Mediterranean and
Adriatic Seas. On a fine spring day they are
almost always to be found on the shore, where
these large, reddish blue, living hemispheres are
wrecked, and soon melt away. Indeed, the
bodies of all jelly-fish contain so large a pro-
portion of water that when a tolerably large specimen is laid on blotting-paper it
evaporates, leaving no other trace than its outline on the paper. In these

Chrysaora (nat. size).

JELLY-FISH, ETC.

493

medusae — which are well known to all who dwell on the coast, and range from one
to seven inches in diameter — we have the most highly-developed of the simple
Ccelenterates. Their body consists for the greater part of the circular umbrella,
the margin of which is notched all round so as to hang down in large or small
lobes. There are also, along the margin, from four to eight or more eye-like
spots, and extensible filaments. At the centre of the lower side of the disc is the
mouth, which in some forms lies at the end of a projecting stalk, and is almost
always surrounded by several thicker folded processes for the capture of prey.

Rhizosloma.

In some cases the folded edges of these ribbon-like arms fuse together, leaving
only small sucker-like apertures. Canals run from the sac-like cavity representing
the stomach to the edge of the disc, where they enter a circular canal, often
provided with apertures. The similarity between this apparatus of digestive
canals, and the arrangement obtaining in the Ctenophora is then evident. The
reproductive organs lie either in special sacs round the stomach, or merely in
widenings of the canals. The surface of the skin is provided with innumerable
microscopically small stinging - capsules, and, thus armed, these so-called Disco-
medusse float about in the water, their bodies being but little heavier than the

494

CCELENTERA TES.

water itself. Indeed, the common blue medusa (Aurelia) is slightly lighter than
water, whereas most of these jelly-fish are somewhat heavier than that element,
and sink during the pauses in their contraction.

Discomedusae are also found in the deep sea, one form of a delicate violet, with
darker tentacles, being the so-called Periphylia mirabilis, figured below, which
was dredged from a depth of over six thousand feet during the Challenger
expedition off the coast of New Zealand.

These beautiful quiet creatures, themselves apparently so harmless, are not

Periphylia (f nat. size

exempted from the struggle for existence. Not infrequently, small Crustaceans
belonging to the orders Isopoda and Amphipoda, related to the wood-lice and
sandhoppers, become parasitic upon them, and many genera are attacked by a
small species of fish. These fish collect in small companies under the umbrella of
their prey, eating its arms, and especially their stinging-capsules, which do not
appear to injure them. Although some of these splendid forms develop directty
as jelly-fish from the egg, the great majority commence life as attached polyps, so
that we have here again another instance of alternation of generations. The
sexes are usually separate, and from the egg arises a ciliated larva, which is oval,

JELLY-FISH, ETC.

495

hollow, and somewhat flattened, recalling the shape of a locket. This is the
so-called planula, which for a time swims about, then attaches itself firmly by
the end of its body and becomes pear-shaped, the stalk of the pear being
represented by the attached end ; a horny envelope is then secreted over the whole
surface, the mouth breaks through the free end of the central cavity, four tentacles
appear, and we have a four-armed polyp or scyphistoma. The tentacles increase
in number, and the scyphistoma can produce at its base a number of young polyps
which again can multiply by division. At a certain period, this method of
multiplication by budding of the potyps from the base ceases, and each scyphi-
stoma divides up in quite a different fashion. The polyp becomes horizontally
constricted in several places, until it appears like a number of cups placed one
inside the other; this is called a strobila (pine-cone). When ready, the top cup
breaks away, turns over, and swims as a young
form of medusa, called an ephyra, which gradu-
ally acquires the shape of the perfect discomedusa.
We thus have here an alternation of generations
in which a sexual medusa-generation is succeeded
by an asexually- reproducing polyp -generation,
this again being followed by another medusa-
generation.

In relation to these, and constituting a kind
of transition form connecting the Discomedusae
and the polyps, are the Calycozoa, or cup-shaped
medusae, which either swim about freely or are
attached by their apices, where the firm gelatinous
disc attains its greatest thickness. At the margin
of the disc, these forms carry eight to sixteen
arm - like processes. In the attached forms
(Lucernaria) the ends of these processes are
provided with short tentacles, occasionally broad-
ened into discs and used for attachment, and
also with stinging-capsules. The Calycozoa may
leave their place of attachment and swim about
for a time, with a rotatory motion, and then again
settle down. Lucernaria has been found as deep
as three thousand three hundred feet, but appears
to prefer to settle in shallower water. The
nearest relations of Lucernaria are the Tesserido3. These creatures are small and
swim about freely, having an elegant long bell-like shape. The edge of the disc is
drawn out into alternately longer and shorter arms, eight to sixteen in number.

Tessera (20 times nat. size).

The Sea- Anemones and Corals, — Class Anthozoa.

We turn from the free-swimming Scyphomedusge to the permanently fixed
polyp forms, namely, the sea-anemones and corals ; the latter of which leave
behind them monuments compared with which the pyramids sink into insignifi-

496

CCELENTERA TES.

cance. Wherever these often minute animals settle, they build up great masses of
rock which may form part of the solid ground of the globe. Although Aristotle

and his contemporaries recognised the sea-
anemones as animals, almost two thousand
years elapsed before corals were considered to
be related to them. In describing the develop-
ment of a small coral discovered on the Arabian
coast, and named Monoxenia darwini, Haeckel
states that the polyp, which is one-eighth of
an inch long, is of strictly radiate structure, the
mouth, which lies at the upper end of the
cylindrical body, being surrounded by eight
feathered tentacles. It is attached to some
substratum by means of a flexible disc at the
opposite end of the body to the mouth. It is
clear that it has no hard skeleton, as the
shape of its surface is changeable ; and its
internal structure must be shown by transverse
and longitudinal sections. The development
of Monoxenia commences with the egg re-
peatedly dividing into many parts (C, D, E).
This process, which is common throughout the
animal kingdom and is called egg-segmenta-
tion, in this case proceeds so simply and
regularly that it ends in the production of a
hollow sphere enclosed by a single layer of
cells (G). Each cell sends out a long cilia or
whip -like process (F) by means of which the
larva turns about and swims in the body-fluid
of the parent polyp. One -half of the sphere
now becomes infolded into the other half (H),
and forms what is called a gastrula (I, K). The
term gastrula has taken a great place in zoology
in recent years, since the Russian naturalist,
Kowalevski found that many different classes of animals, in developing from the
egg, passed through such a stage. Haeckel, generalising from these facts, invented
his Gastrea theory, according to which all animals in which the gastrula stage
occurs must have been descended from a common primitive form, Gastrea, which
has, however, in its simplest form long been extinct, but of which the Coelenterates
are the closest modern representatives.

The gastrula of Monoxenia is of the simplest kind, the infolding being
complete, and the larva forming a sac, whose walls consist of two layers of cells,
or germinal layers, an outer ectoderm and an inner endoderm (see section given in
the illustration). The transition from the flat dish-shape (H) to the sac with a
narrow mouth is at once clear, and the knowledge that all the Ca^lenterates proceed
from a similar larva, and that all the complications of their various systems are

Monoxenia darwini (highly magnified).

SEA-ANEMONES AND CORALS.

497

developed from such a simple gastrula, throws much light on their anatomy. During
these transformations, the endoderm, whose cells multiply, continues as an uninter-
rupted lining to the stomach and its appendages, while the ectoderm yields the
constituents of the skin. A third intermediate gelatinous layer, the mesoglcea, arises
between the outer and inner
layers; in this, muscles and
connective interstitial tissues
appear. The chief part of the
jelly forming the great umbrella
of the Discomedusae consists of
this mesoglaea. In the mesoglaea
of one division of the corals the
calcifications take place. These
internal calcifications play, how-
ever, but a very small part in
the great rock-making activities
of corals as a whole, the most
important calcifications being ex-
ternal. Returning to Haeckel's
account of Monoxenia, although
the transition from the gastrula
larva to the adult animal has
not been observed, there can be
no doubt as to how it takes
place ; all the transformations
having been watched in other
species. The larva attaches it-
self with the end opposite to the
mouth, the cilia disappear, and
after the mouth -tube (p) has
been formed by the folding in
of the anterior end along the
longitudinal axis of the body
(L, o, a), and has thus become
marked off from the stomach
(g), the eight hollow tentacles
rise round the mouth as out-
growths of the body-cavity, or as direct continuations of the stomach. Like all other
corals, Monoxenia periodically multiplies by means of eggs which arise either in
the walls of the radiating stomach partitions (or septa), or on their free edges, and
have to be ejected through the mouth, as development does not in this case take
place within the digestive cavity of the parent polyp. As a rule, the polyps are
either male or female, but in stock-forming species individuals of the two sexes may
be mixed. Hermaphrodite individuals are less frequent.

Monoxenia may be taken as the simplest type of the regularly radiate polyps ;
in all radiate animals the different organs being repeated in regular rings round

VOL. VI — 32

stages in development of Monoxenia darvnni
(highly magnified).

498

CCELENTERA TES.

the central axis. Monoxenia and similar animals are considered simple, because the
repeated organs develop similarly and simultaneously, and are comparatively few
in number. The mouth, too, is circular. In many other polyps, however, the

regularly radiate type is slightly departed

__8 from ; the mouth, instead of being round,

forming a long slit, while there is a tend-
ency for the originally radiate animal
to become bilateral. From this account of
a simple polyp, it is easy to understand
what kind of animal it is which makes
coral ; and our readers, if they have not
already done so, will give up speaking of
" insects building up the coral - reefs."
It is, however, by no means all such
polyps that form coral, nor do those
which form it produce it always in the
same way. Numbers of polyps, such as
the beautiful sea-anemones, never produce
any hard substance, but remain soft and

delicate, though dangerous, at least to
small animals, because of their stinging-
cells. Many of these soft sea-anemones
are highly specialised creatures, as may
be seen from the coloured Plate; but
those which secrete coral are generally
simpler, and smaller, and grow in vast
colonies. It is the accumulation of all
their little contributions of coral which,
in the process of time, build up islands or
even continents. In regarding coral
animals as reef -builders, we may leave
out of account, as unimportant, those
which form hard spicules within their
bodies, and consider only those which
perform most of the work. Imagine a
crowd of small animals like sea-anemones
fixed to a rock, each one secreting a layer
of carbonate of lime between itself and
the rock, and this layer becoming thicker
and thicker till each polyp rises on a
little pedestal. There is probably a race
between them, as there is among trees in a forest, which shall reach the highest
to get most of the food as it passes by on the currents in the water. Now, it is
obvious that a crowded colony of polyps like this would in a short time add a
thick layer of solid carbonate of lime to the rock on which they first settled, and
this is, in brief, the principle of reef -building. As a matter of fact, however, it is

Monoxenia darwini (magnified).

L, Longitudinal section, on the left, through one of the
interseptal cavities, on the right through one of the
partition walls ; M, Transverse section through the
line m n; N, Transverse section through the line
s b t ; O, The eight-lipped mouth-aperture, with the
bases of the arms ; a b c o, Principal axis ; p,
Pharyngeal cavity ; g, Digestive cavity ; k, Divisions
of the digestive cavity ; to, Radial septa or walls
dividing up the' digestive cavity ; e, Masses of eggs ;
u, Mesenterial filaments ; /, Masses of muscle and
connective tissue.

SEA-ANEMONES AND CORALS.

499

not quite so simple. The layer each polyp secretes is not a smooth flat disc, evenly
secreted by the whole surface of its foot. Some parts of the foot secrete more
than others, hence those parts rise up as spines, walls, and rings, which protrude
into the body of the polyp without, however, breaking through the skin. These
probably help to fasten the polyp to its pedestal, and prevent it from being swept
off' by strong currents. The figure on p. 505 is a good illustration of one of these
plates. Each genus of corals has a pattern of its own, each one perfect and beauti-
ful in its way, and it is frequently a puzzle to discover how it is made. When a
crowd of polyps grow in contact, their pedestals will also grow in contact and
form continuous masses ; this growing in contact being ensured by their ordinary
method of multiplication. For a coral-polyp does not have to wait until another
takes up a position beside it, but as soon as it can feed freely, it begins to bud or
divide, producing a number of young polyps close around it. These also bud in
their turn and are soon surrounded by young polyps, and in this way such compact
colonies are formed that it is a struggle among the inner ones to avoid being
suffocated. We thus have densely crowded colonies of polyps struggling upwards,
each individual secreting a more or less beautiful and complicated pedestal. The
pedestals are fused together in a hundred different ways, and from these different
patterned pedestals, with their various ways of fusing together, are produced the
almost countless different kinds of coral which together build up coral-reefs.

In a growing polyp-stock the individuals usually remain in organic connec-
tion, that is to say, each first provides for itself, and then shares its superfluity
with the others, sometimes by means of a continuous reticulated system of canals
running from polyp to polyp, perforating the stony substance which often separates
the members of the one stock from another. The whole stock may thus be
physiologically one creature with many mouths. Where, however, the secretion of
the pedestal is very rapid and the budding very slow the
polyps may separate, each standing at the end of a branch ;
the illustration of Caulastrcea showing an example of this.
It will be understood from this description that only the
layer of growing polyps with their intercommunications
can be spoken of as living ; and as this layer rises higher
and higher by secreting fresh layers of carbonate of lime,
the living linings of the communicating canals are either
withdrawn or die away, and all beneath the living layer
is mere dead matter built up and left behind by the
coral animals.

Before passing to our survey of the corals themselves,
two other points deserve attention. Not all corals form
stocks. Some remain single, like the mushroom-corals
(Fungidce), which grow to a very large size with a heavy
solid skeleton ; and although these form new polyps by
budding, the latter become detached and live as solitary
individuals. Again, although coral-reefs are due to the great power of multiplying
by division or budding, yet all corals, so far as is known, also at certain times
produce eggs. The further development of these eggs gives rise ultimately to a

outline OF Caulastrcea
(nat. size).

5°o

CCELENTERA TES.

small polyp, which settles down and commences to secrete its pedestal and then to
bud, thus starting a new coral-stock.

Six-Rayed Polyps, — Order Hexactinia.

This name must not be taken too strictly. It is true that it was applied in
good faith, because it was believed that this order always had exactly six or
some multiple of six as the number of the tentacles ; but corals are tied by no
such rigid rules, and all we can say is, that the number of tentacles in this
order generally approximates to some multiple of six. Among the Hexactinia
the sea - anemones take the first place. They spread over all seas, being
especially plentiful in the temperate zones, near the coast, at depths which
bring them within the reach of every observer. They are distinguished by their
solitary manner of life, their size, and their vivid and usually beautiful colouring.
The skin is firm and leathery, and often covered with warts. It does not secrete
any calcareous skeleton either inside or outside, so that the animal is soft and

capable of great contraction and changes
of shape. Most sea-anemones use the
basal disc for attachment, and can move
from place to place by means of it, but
a few species bore into sand with the
posterior end of the body, or else secrete
or build a sheath which they inhabit.
In our coloured Plate are depicted, in
their natural brilliant colours, a number
of sea -anemones living in the Naples
aquarium. To the left, in the fore-
ground, are two examples, one extended
and the other contracted, of the red
Actinia equina, which varies greatly
in colour. In the centre of the group,
somewhat to the left, there is an ex-
tended specimen, and near the right
edge a strongly contracted specimen of
the lovely green Actinia cari. Other beautiful forms are found in the two
striped anemones, Ragactis pulchra and Cereactis aurantiaca. The sun-anemone
(Heliactis bellis), again, varies greatly in colour but is always elegant, and the
same may be said of the trumpet - anemone with spotted tentacles {JEptasia
niutabilis). In the foreground at the centre a hermit-crab is seen carrying with
him his guest, the cloak-anemone (Adamsia palliata). A less conspicuous anemone
(Eloactis mazelii) is provided with somewhat long cylindrical tentacles. The
Anemonia sulcata lets its tentacles float gracefully, while the vestlet (Cerianthus
membranaceus), of varying colour, hungrily stretches out its arms in all directions.
Cladactis costal, which is covered with warts, is no less voracious, but with apparent
apathy allows its tentacles to droop around it.

These quiet, externally beautiful, and apparently harmless creatures are in

larvje of sea-anemone (magnified).

,

SEA-ANEMONES.

5°i

reality extremely voracious, devouring large pieces of flesh, and sucking down
mussels and oysters. When fed in an aquarium, the long grasping tentacles
greedily surround the food, such as morsels of flesh, small fish, or crabs, given to
them, and convey it to the mouth ; not merely are the juices sucked out, but the
flesh itself is digested, only the fat being rejected. Well-fed anemones change
their skin frequently, no doubt because of their quick growth. During this
process, they remain closely contracted, expanding again after it is completed ; the
shed skin forming a loose, dirty-looking girdle round the base of the foot. Anemones
only settle in places where the currents bring them the animal food they need ;
and are most plentiful where the current is strongest, as, for instance, at the
entrance of harbours or on rocky coasts. Some species are in the habit of settling
on other animals whose requirements make them frequenters of disturbed waters,
hermit-crabs being especial favourites. Certain species again, such as the large
yellow - and - brown - striped Actinia effceta (see illustration below), are indeed
always found fixed upon the shells inhabited by
these crabs, the one mentioned being generally
found with Pagurus striatus, a large Mediterranean
crab which inhabits whelk -shells of suitable size.
Two or three of these anemones often settle on one
crab, which does not seem to be at all incommoded
by his burden, while the former profit in the matter
of food by the wanderings of their host.

On account of the ease with which anemones
are kept in captivity, their manner of reproduction
has been well observed. With rare exceptions, they
develop from eggs. Dalyell kept one for six years,
and reared from it upwards of two hundred and
seventy-six young ones. Two of these young lived
for five years, producing eggs at ten or twelve
months old, which hatched a couple of months later. He saw that the ciliated,
infusorian - like larvae (see illustration on p. 500) settled down on the eightli
day, losing their cilia, the first tentacles appearing during the process of attachment.
Young anemones often pass through their whole development within the body-
cavity of the parent. Even in a free condition sea-anemones can easily be studied.
Gosse has well described the many British species, and Lacaze-Duthiers has given
a still more detailed account of several kinds studied in connection with their
development. He gives many details of the common European Actinia equina
found along the coasts of the English Channel in all rocky parts at low-water
level. Its colour varies between scarlet, rose-red, dark red-brown, and olive-green,
a distinguished characteristic being a -circle of beautiful blue warts below the
tentacles.

Most anemones are provided with several circles of more or less similar
cylindrical tentacles, but there are some specially beautiful species which, besides
tentacles of the usual shape, have, either within or outside of the circle of ordinary
tentacles, lobed or leaf -like tactile and seizing organs. These belong to the family
of the Crambactinidw. The beautiful Crambactis from the Red Sea, shown in the

a sea-anemone, Actinia effceta
(nat. size).

5©2

CCELENTERA TES.

illustration, has, immediately round the mouth, several circles of delicate grasping
tentacles, shaped like curly cabbage or endive leaves. Below these comes a circle
of numerous thick arms altogether unlike the others, being rough-skinned, and of
a simple spindle shape, the body itself forming a thick disc. All the tentacles of

endive-anemone, Crambactis (somewhat less than nat. size).

the sea-anemones are hollow, with a fine aperture at the tip, through which, when
the animal contracts, the water contained in the body-cavity can be expelled, but
in the deep-sea forms these organs are very curiously modified. For instance, in
the genus Polysiphonia, here illustrated, the tentacles are short and unsuited for

catching and holding prey ;
but the aperture at the tip
is large, and through it
flows in water containing
organic detritus which can
be used as food. The allied
Sicyonis has sixty - four
wart - like tentacles with
wide apertures standing in
a double circle round the
mouth, and in Liponema
the body- wall is perforated
by several hundred aper-
tures leading into the
digestive cavity and corre-
sponding to the tentacles.
Although most mem-
short-tentacled ANEiioNE, Polysipho7iia (nat. size). bers oi the group arise as

SEA-ANEMONES.

5°3

single individuals from eggs, some multiply by the detachment of small pieces from
the pedal disc. Fischer observed this process in the translucent anemone (tiayartia
pellucida) on the French coast. The pieces detached
on the 23rd of August had, by the 7th of September,
developed into small individuals with fifteen or
sixteen tentacles. Multiplication by fission seems
common in several species, such as S. ignea, and
always ends in producing single individuals. Sea-
anemones sometimes, however, form stocks, but are
then no longer called Actinia but Zoantharia. Such
stocks are not very numerous, but some species can
be found on European coasts. The genus Zoan-
tharia, in which the separate individuals are united
by a creeping branching root, is distinguished from
Palythoa, in which the common stock resembles a
root-like crust, on which the polyps form irregular
groups of various sizes. A peculiarity common to
the two genera is the incorporation of hard particles
of the most different kinds — sand, sponge-spicules,
pieces of shell or coral — into the body- wall in large
quantities. The walls in consequence become so firm
that the exact form of the polyp is retained in dried
specimens. The species of Palythoa, although un-
attractive when in spirit, are of a sulphur yellow,
and beautiful when alive in an extended condition.
The most interesting species is Palythoa fatua,
which is always found growing on and in one of
the most curious of sponges, the Japanese glass-
sponge {Hyalonema). Here the surface of the stalk,
that is above the portion embedded in the mud, is
covered with a warty crust belonging to this
Palythoa. All the specimens of this Japanese
sponge in European museums in 1860 had their
stalks overgrown with the Palythoa, while many
had their bodies also covered with another polyp
which, however, settled singly and, fortunately for
the sponge, did not form a sandy crust. The illustra-
tion represents a specimen of this beautiful glass
rope-sponge, its body pitted all over with holes in
which small Anthozoa once lived, and its stalk
coated with the sandy crust of the stock -forming
Palythoa. The former, having no skeleton, dry up
entirely; no traces of them being found in dried
specimens of the sponge except the holes they lived in. Unlike a parasite, the
polyps do not feed upon the juices and soft-parts of the sponge, nor indeed do
they share its food, but simply settle upon the sponge and feed upon the food that

PARASITIC ANEMONE (Palythoa) ON
STALK OF GLASS - ROPE SPONGE

(J nat. size).
The holes on the body of the sponge
are formed by anthozoans.

5°4

CCELENTERA TES.

may chance to come within reach. It is interesting to note that a Palythoa
closely related to the Japanese form occurs in the Adriatic, and is also attached to
sponges, scarcely a single specimen of the sponge in question being found without
its polyp guest. The larvae hatched from the eggs of the Palythoa evidently
perish unless they meet with one of these sponges ; but the manner in which they
find and recognise their particular host is quite unknown. Other species of
Palythoa found on the American coast settle on the shells inhabited by hermit-
crabs, covering the shell as an uninterrupted mass several lines thick, and the

individual polyps rising to about an equal height above
the general mass. The shell becomes disintegrated beneath
this cover, and the polyp-stock then remains as the only
covering to the crab. In this case there is mutual
advantage, for the crab is covered and protected by the
polyp-stock, while the polyp profits by its wanderings and
enjoys constant change of water and new fields for food.

An extraordinary form, very nearly allied to Zoantharia,
has been described under the name of Polyparium
ambulans, and is found in the strait dividing the island
of Mindanao from that of Billiton. It consists of a colony
three inches long and six wide, flattened from above down-
ward, and therefore more or less ribbon - like ; and the
anterior cannot be distinguished from the posterior end.
The upper surface of the colony is covered with peculiar
polyps shaped like chimneys, the base being much wider
than the top, which carries a round aperture. Each polyp
is extremely minute, and has no tentacles. They stand
in irregular transverse rows of from five to eight, differing
in age and therefore in size ; the lower side, on which the
The small dried-up polyps are colony rests, being beset with protuberant suckers. These
^branching sponge.1* ° a^so differ much in size, but stand in regular rows divided
by furrows, and serve for attaching the colony, and also
enable it to creep. The colony can even be seen slowly climbing up and down small
stones. The polyps have no septa in the digestive cavity, the inner side being quite
smooth ; and the lower end of each is not closed, but communicates with a large
cavity running along the whole colony, and divided at regular intervals by partitions.
From the foregoing observations it will be seen that in the soft
division of the Hexactinia, or six-rayed anemones, there are both
single individuals and colonies of individuals joined together to form stocks ; and
there is also the same diversity in the skeleton-producing division — the corals
proper, where we have both single individuals and stocks. Whereas however, in
the soft division, the simple individuals are the more numerous and the colonies
comparatively rare, among the corals the opposite is the case, the colony-forming
types presenting almost innumerable varieties. This is not difficult to understand;
since the soft anemones cannot well form complicated colonies, whereas the skeleton-
forming polyps, by combining their skeletons, can build complicated structures, in
order to raise themselves into more advantageous positions. We have first, then,

Palythoa axinellce (somewhat
less than nat. size).

True Corals.

CORALS.

5°5

simple coral, Thecocyathv.s
(nat. size).

to consider those corals which do not typically form stocks, but remain at the stage
of a simple sea-anemone, only with a rigid, calcareous skeleton supporting, and no
doubt protecting, them in different ways. All the corals found in British seas are
(with the exception of the so-called tuft-coral) single, and generally very small. As an
example of a regular, circular, solitary coral, we may take Tliecocyatlius cylindraceus,
the skeleton of which is shown in the illustration. The
animal when expanded fills up the central depression, but
when, on expelling the greater part of the watery contents
of its cavity, it contracts, the whole body seems to sink
into the hollow cup formed by its skeleton. In the
illustration we see only the outer wall and the top of the
ring of septa, which are solid vertical plates, rising up
from the pedestal secreted by the foot and radiating out-
wards in all directions. Two other solitary corals are
worth describing, as they show certain interesting special-
isations. Both of them may increase by budding, that is,
by the method which, in colony-forming corals, leads to the
formation of stocks, if the buds remain attached to their parents. When, however,
solitary corals bud, the buds fall off, and lead solitary lives like their parents.

Most of the numerous species of the scarlet crisp-corals (Flabellum) are
individuals, and are characterised by the slit-like form of the mouth. At a in the
illustration the living animal is seen from above, while b shows a side view of the
skeleton, which is attached. It resembles a pair of fans fastened along their edges ;
and just inside the outer edges of the fans is the row of tentacles. The whole
animal is as if the upper end of a circular polyp had been squeezed, so that the
mouth-area, instead of being round formed a long oval (a). An interesting case of

budding occurs in these corals,
the buds falling off. In the
illustration, c shows the bud
growing out at the top of an
individual like b. In this
budding condition the coral
might pass for a different species
of Flabellum. The bud, how-
ever, ultimately falls off (d), but
instead of becoming attached,
is swept by the waves into some
rocky fissure, where it spends the
rest of its life. Besides the fact
that it remains unattached, this bud differs from its attached parent in a far more
important respect. It can produce eggs, which the fixed coral can not do, so that
we have here another case of alternation of generations. Out of the egg comes
an attached form, which buds and produces the free unattached form, which again
produces eggs, and so on. The predominating colour of this species is a beautifully
intense and yet transparent red, the mouth-disc having almost always broad bands
of darker red, most marked in the paler specimens.

scarlet crisp-coral, Flabellum (nat. size.)

506

COELENTERA TES.

The mushroom-corals (Fungiidce) are another remarkable group of solitary
forms, taking their name from their resemblance to the head of an expanded mush-
room turned upside down. Turning to the figure of Thecocyathus (on p. 505), and
imagining the circular wall pulled down all round, and drawing down the septa so

that they radiate outwards, some idea of a Fungia may
be obtained. Their skeletons are remarkable objects, which
no one, at first sight, would in any way connect with a sea-
anemone. Although the mushroom-corals are considered
to be individuals, reproducing themselves by means of
eggs, both budding and division into halves occur excep-
tionally ; in the former case the buds sooner or later
becoming detached. In some there is an alternation of
generations, leading to the formation of compound stocks.
In the illustrated form true mushroom-corals are produced
at the ends of the branches; at a one has become detached,
mushboom- coral budding and an(j the others are in different stages, the youngest being

FOBMING A SMALL STOCK , ,. , . , ,.', , . , , , ,. , ,

(nat size) nearly cylindrical, like a typical polyp, whereas the older

ones spread out like a typical Fungia. When a bud has
fallen off, the stem seems capable of developing another. This is the asexual genera-
tion, reproduction by eggs being the sexual generation. Lastly, certain solitary corals
have recently been discovered in the deep sea, where, on account of the presence of
carbonic acid in suffi-
cient quantities to
make itself felt, there
is little lime. On this
account the calcareous
skeleton is generally
distinguished by great
delicacy. A deep-sea
coral with such a deli-
cate skeleton (Lepto-
penus), found off the
east coast of South
America at a depth of
over a mile, is shown
in the illustration. Its
pedestal is formed of a
delicate network with
fine rays or spokes,
connected together in a
regular manner by
transverse supports.

Plentiful as are the solitary corals, they are surpassed in number by those
which form compound stocks ; that is to say, in which the buds do not fall off but
go on budding till coral-islands and barrier - reefs are built up. As it is im-
possible to give here more than a very few illustrations of the many different ways

A deep-sea coral, Leptopenus discus (nat. size).

CORALS.

5°7

in which the coral-stocks grow, we can only select a few types. In Dendropliyllia,
as shown in the illustration, we have a tree-like growth ; each polyp secreting a

A solid pedestal for itself,

and living in a depres-
sion in the top. This
is shown in the section
B. Into this depres-
sion the soft animal

n

1

Mil

11

11

S3?

K«A

A branching coral, Dendrophyllia.
A, Terminal branch of a stock (uat. size) ; B, Longitudinal section of a single polyp (magnified).

can withdraw at the approach of danger, drawing all its tentacles (which also
contract) down to a. The space occupied by the animal is not very roomy at
the best, and it is further limited both by a great columella d, rising up in its

interior, and by the solid septa b projecting into it
all round. It must not be forgotten that these parts
are not in the animal but outside of it, and as they
are secreted they push the skin up and never pene-
trate into the tissues themselves. These polyps bud
at intervals, the apical polyp most frequently ; and
the result is a simple branched stock, as seen.

A different kind of stock is developed when the
polyps produce many buds, as in the madrepores.
In these delicate stocks, selected polyps spring up
above the rest, and their sides become covered with

small buds. Space
would obviously
not permit all
these small buds
to bud again in
the same manner.
A few favoured
ones, however,
which have suffi-
cient room next
spring out and

a madrepore coral {Madrepore, verrucosa), become covered

In the section B the canals which connect the polyps through the stony skeleton are seen, again with small

5o8

CCELENTERA TES.

buds. Each bud is a living, feeding, coral-animal, surrounded by its crown of
tentacles. These madrepores play no small part in building up coral-reefs, and
the many different elegant forms which they assume (while keeping to their
method of budding) is astounding. Some corals, again, do not form true branches,
but may cover the ground like a field of corn, — a good example of this type being
found in Cladocora ccespitosa, which inhabits the Mediterranean and Adriatic seas.
Here the single individuals form somewhat long tubes, and the buds arise
laterally at the lower end, then bend upward and grow alongside of the parent,
without any further connection or fusion. The spaces between the different
rising polyps are not filled in with secreted hard matter, but the latter grow up
side by side free. The stock, therefore, is easily broken. This coral nourishes
extraordinarily in many places, covering areas of over one hundred square yards,
with a growth of a foot in height.

The method of growth just described is shown also by another and quite
different coral, Astroides calycularis. As in Cladocora, just described, the single

a massive cohal, Astroides (nat. size).

polvps, with their calcareous tubes or pedestals, are not fused together by any
cementing substance. The yellowish red polyps are seen standing out a great
height above their cavities, much more so than is usual in corals. The larvae of
these corals leave the egg while still in the large, chambered body-cavity of the
parent, where they swim about for a time, till they escape through the mouth.
They are long and worm-like, and slightly thicker at the posterior end, but may
change considerably in shape. They swim about rapidly by means of their
covering of cilia, the thicker end being foremost. The mouth appears at the thinner
end soon after the larva leaves the body of the parent. Its free-swimming life has
been known to last as long as two months ; but under natural conditions it would
probably be shorter. A strong sirocco had a marked effect upon the larvae, which

CORALS.

509

seemed to become exhausted, contracted, and became attached. The transition
from the worm-like larva to the polyp takes place as in the anemones. The
thicker end of the body is pressed against a hard rock, and the whole contracts
into a thick, round disc ; while longitudinal furrows become visible at the upper
pole, where the mouth sinks deeper. At the ends of these furrows the twelve
tentacles appear. The accompanying three illustrations show the stages which

developmental stages of Astroides calycularis (maguified 24 times).

follow in rapid succession, resulting in a form almost exactly like a young sea-
anemone. It has, however, already commenced to secrete its calcareous skeleton.
This is not formed as a connected whole, but begins as a number of separate centres
of secretion between the polyp and the substance to which it is fixed. These meet
and fuse, till gradually the skeleton is produced. The polyp commences to bud,
and the buds develop their skeletons, the whole together forming a stock like that
shown in the illustration.

The star-corals, which are some of the principal reef-builders, do not branch,
but form great solid mounds;
the polyps being all cemented
together, and the budding so
arranged that the whole colony
forms a thin, living layer or
covering to the mass it and its
parents have built up; all but
this thin layer on the surface
being dead coral. The illustra-
tion given is of Astrcea pallida,
a species which appears as a
rounded mass, with flat base, and
the individuals being quite dis-
tinct from one another, although their outer walls are in contact. Those on
the top and to the right of the figure are represented in a contracted condition,
and the rest with expanded tentacles. None of the individuals here seen are in
the act of dividing; and the genus is characterised by the fact that the bud-

a star-coral, Astrcea (I nat. size).

5TO

CCELENTERA TES.

ding polyps separate from one another completely, forming so many distinct
individual polyps.

In the brain-corals, or Meandrina, we have animals budding, but not com-

A BRAIN-CORAL.

A, Stock with the soft-parts ; B, Skeleton. (Nat. size.

pletely separating. No hard wall grows between the bud and its parent, although
such separate the polyps less closely related. We thus get a system of valleys

THREE MOUTHS, WITH TEN-
TACLES AND DIVIDING
WALLS OF BRAIN-CORAL.

with rows of mouths,
belonging to the
polyps, which have
budded off from one
another. The valleys
are bounded on each
side by the hard
walls separating
them from similar
valleys containing
similar series of
polyps. The three
illustrations will en-
able the reader to

Understand this brief A horny coral, Antipathes arborea (nat. size).

description.

„ „ We have hitherto described skeletonless forms, and forms

Horny Corals.

secreting solid, stony skeletons; the Antipatharia have horny

CORALS.

5"

skeletons, the method of secreting which will be described when we come to
the horny skeletons of the next group. The polyps have only one, instead of
several rows of tentacles, and in most of them the tentacles are six in
number. They form compound stocks, looking like delicate shrubs, with long
branches, from which the polyps project, these branches being supported by a
flexible horny axis. In the Fiji Islands a stock three feet high, with a stem half
an inch in thickness, has been found. The general form of the whole stock, the
brown colouring, and the small, thick tentacles of the little polyps are not
attractive.

The Eight-Rayed Polyps, — Order Octactinia.

Although this second order of the corals contains a variety of forms, the
appearance of the individual animals is more or less uniform, the number of
tentacles being always eight. The tentacles are not hollow, but are usually some-
what flattened and notched round the edges like delicate leaves. These corals
form stocks which are sometimes knobbed or lobed, and sometimes resemble a
hand or tree with simple branches. The individuals of the stock are usually
small and rise like minute white blossoms above the soft fleshy surface of the
stock, which has a peculiar reddish yellow glistening appearance. The stock
attaches itself by means of a stem, or else rests loosely in the sand, generally
at a moderate depth. These corals secrete carbonate of lime, but in no case in
the same way as do the true corals or the hydrocorals. In both these latter
the solid skeleton is formed by the outer skin, while in the present group
the secretion takes the form of minute calcareous particles of definite shape
scattered about between the outer skin and the lining of the body-cavity. These
spicules never fuse together to form solid continuous masses, but may, neverthe-
less, be present in sufficient quantities to give the lower part of the body a certain
degree of rigidity. When fresh, the stocks show some elasticity and turgescence.
When removed from the water the whole stock contracts strongly, but swells out
again if placed in an aquarium, where it may live for weeks or months, although
the great swelling of the lower part shows that its condition is abnormal. A
tendency to form a stem is also common. The illustration on p. 512 shows an
alcyonarian, as these corals are called, with its lower part modified into a stem
free from individual polyps; while the next figure exhibits a representative of
another family, the sea-pens (Pennatulidce), which also form stocks divided into
a polyp-bearing area and a stem resting on the sea-bottom. In one of the simplest
forms of the sea-pens (Veretillum) the upper part is simply surrounded by polyps,
and the lower a cylindrical stalk. A stock of this last-named type may lie for two
or three consecutive weeks like a wrinkled turnip at the bottom of an aquarium,
with all its activities suspended ; no individual polyp appears ; no food is taken in,
and the circulation of water, necessary for the life of the stock, does not take
place. After a time, however, the fine pores begin to take in water again, the
surface becomes smoother, and gradually, as the individual polyps appear and
stretch out their tentacles, the colouring of the whole stock becomes more vivid
and more delicate. The stock lengthens and thickens, and the white crowns of
tentacles stand out in dazzling contrast to the red of their bodies and of the

512

CCELENTERA TES.

common trunk. The foot swells out like an onion and becomes transparent,
curves, and sinks into the stand ; and the stock, which during its period of
inactivity lay prone on the ground, assumes an erect position. In these sea-pens

an alcyonarian coral, Alcyonium (nat. size).

the parts of the stock may be compared with the parts of a feather, the whole
being bilaterally symmetrical, and the single polyps being carried on the leaf-like
lateral appendages of the stem. The sexual animals, which are provided with all
the organs necessary for a polyp, take in the food and reproduce themselves. The
other less perfect brethren, called zooids, although more or less resembling these,

CORALS.

5*3

have remained at a lower stage of development, are smaller, and have neither
tentacles nor reproductive organs. These zooids appear to perform only one
function, namely, to pump water through the body of the stock. In this important
work the higher individuals no doubt assist, as indeed in most alcyonid-stocks
they alone must do the work, there being no such specialised pumping-polyps.

In addition to the small, isolated calcareous particles already mentioned
within the bodies of the individual polyps, sea-pens have a further support in the
form of a calcified and often flexible axis, entirely concealed in the stock and
pointed at the two ends. The accompanying illustration represents Pteroides
spinosa, in which the polyp-bearing leaves are supported
by a number of calcareous rays which project at the
edges as spines.

The best known of the sea-pens is the phosphorescent
Pennatula phosphorea of the Mediterranean and the
Atlantic. In this form the capacity for giving light sis
not possessed by the whole surface of the stock, but
only by eight band-like organs on the polyps themselves,
the upper ends of which surround the mouth like
papillae, while their lower parts run down over the
stomach. These bands are filled with cells containing
fatty spherules, to which the phosphorescence is con-
fined. The fact that these luminous bodies have been
found in all parts of the stock is explained by the
liability of the bands to ba injured, the least pressure
causing their contents to escape. Specimens which have
been roughly treated when captured and have strongly
contracted, as also those which have been kept for any
length of time in small vessels and have become dropsical,
are incapable of giving light. The phenomenon is only
observed in freshly-caught and little-disturbed animals
Very slight irritation, such as is produced by tapping on
the glass of the aquarium, is enough to call forth flashes.

If the animal is taken in the hand, either in or out of water, still brighter luminous
spots and streaks are seen. Repeated careful experiments have revealed the fact that
the streams of light follow regular courses. There are two kinds of streams ; the
one connected with the polyps proper, and visible on the dorsal side of the feathers,
and the other connected with the zooids, and appearing on the lower side. The
two streams appear at the same time, as a rule, but either the one or the other
may, without any apparent reason, arise independently. It can be shown that the
direction taken by the streams depends on the part to which irritation is applied.

The higher forms of the sea-pens, or those which actually resemble feathers, are
not found in deep water, none being recorded to exist below six hundred fathoms.
Deep-sea forms have, however, been found; these being related to Umbellula
grcenlandica, which has long been well known. As early as the middle of last
century, when the presence of animal life at great depths was quite unknown, two
specimens were brought up from a depth of two hundred and forty fathoms,

vol. vi. — 33

a sea-pen, Pteroides spinosa
(I nat. size).

a, A polyp (somewhat magnified).

5*4

CCELENTERA TES.

sixty miles from the coast of Greenland. The polyp-stocks consisted of a long,
thin stem, ending in a bundle of polyps. The larger specimen was two yards long.

These two
specimens, soon
after being
described, were
lost, but a very
similar form
( U. thomsoni)
was obtained
during the
Challenger ex-
pedition ; and
other species have been
discovered in various lati-
tudes, at great depths. -
Two were found between
Portugal and Madeira, at
two thousand one hundred
and twenty fathoms, while
U. leptocaulis was taken in
the Indian Ocean, some two
thousand five hundred
fathoms below the surface.
The accompanying illustra-
tion shows a species (U.
encrinus) from the northern
seas.

Another family of
eight -rayed corals is that
of the sea -fans, or Gorgo-
niidce, of which the beauti-
ful, horny, tree, and bush-
like growths give no idea of the living coral. In
order to gain an idea of the latter, we must picture
these trees thickly covered with beautiful eight-rayed
anemones. As in the case of ordinary corals, the
polyps secrete the horny branches beneath their bases,
and on these they rise in gracefully branching colonies.
All the sea-fans are attached, and branch in the most
various ways, some in all directions, others only in one
plane ; in some cases simple branches run out at an
angle or spirally, forming fans or nets, etc. In most,
the axis is horny and flexible, and they might be
called horny corals, but single calcareous particles are
enclosed in the axis, and its soft covering is crowded Umbellula encrinus (nat. size).

Umbellula thomsoni (nat. size).

CORALS.

5i5

with them. The different kinds of these particles, found in different species, are of
great importance in classification. One of the most common of the group is
Gorgonia verrucosa, found in the Mediterranean, and here illustrated. A
shark's egg is shown in the illustration attached to the coral by means of its

a sea-fan (Gorgonia verrucosa), with a shark's egg fixed to its branches (nat. size).

appendages. The soft covering of this Gorgonia is white. These animals occupy
no very important place in the economy of nature ; but several gastropods seem to
attack the polyps, and brittle-stars climb up the branches in search of food. A
beautiful form is Isidigorgia, resembling a corkscrew with a long spiral. It sends
off at right angles to the principal axis, and at short intervals, delicate branches,

5x6

CCELENTERA TES.

y

so that the whole structure looks like a spiral staircase constructed of fine cord.
The accompanying illustration shows an allied form (Streptocaulus) of the family

c .. .___ Chrysogorgoniidcc, as yet found only in the Western

Atlantic. The simple or branched colonies are as thin
as horsehair, and the delicate axis has a golden sheen,
with a beautiful display of colours.

The genus Isis, the stock of which is partly horny
and partly purely calcareous, forms a transition between
the above and the red coral (Corallium rubrum). In
the latter the axis is calcareous, and built of numerous
fine layers, the microscopic structure of which is so
definite that a connoisseur can detect false from real
coral. The fresh axis is covered with fine longitudinal
furrows, in which run the deepest of the canals connect-
ing the polyps with one another. The stocks, as a rule,
consist either purely of male or purely of female in-
dividuals, although occasionally the two sexes are found
on one and the same stock, and even individual polyps
which are both male and female sometimes occur. In
the illustration, a slightly magnified branch of a stock
is represented, with several retracted polyps and two
cut open. In the upper exposed calyx (o), eggs are seen,
while the lower (t) contains a large male vesicle, and at
its side an egg (o). After hatching, the ciliated larvae
leave the egg while still within the chambered cavity of
their parent (B). Two of the long worm-like larvae (/, g)
can be seen in the illustration through the delicate body-
wall of a polyp whose tentacles are retracted, and others
are visible in a cell which has been cut open. In the
uppermost cell a larva (a) is seen in the act of passing
out through the mouth (b). The red coral is found only in
the Mediterranean and Adriatic seas: the most noted coral-
fisheries being carried on off the Algerian and Tunisian
coasts, at depths of forty to one hundred fathoms. The
coral obtained in these fisheries varies greatly in value.
The price of the broken pieces, often perforated by worms
and sponges, is from five to twenty francs the kilogramme
(2 lbs.); good coral fetches from forty-five to seventy francs,
while choice thick coral, especially the rosy red kind, is
bought at from four hundred to five hundred francs the
kilogramme. Such pieces as are black, either superficially
or throughout their whole thickness, are sold separately
at from twelve to fifteen francs the kilogramme; these are
not of a different species, but,having long been covered with mud,have changed colour
as a result of chemical changes. The coral is made into articles of ornament both
in Paris and Marseilles, but the chief industries are in Naples, Leghorn, and Genoa.

COKKSCKEW sea-v A.x?Streptocaulus
pulcherrimus (nat. size).

CORALS.

5U

We conclude our description of these eight-rayed corals with the organ-pipe
corals (Tubiporidcv), a family consisting of the one genus Tubvpora. the members
of which are neither numerous nor varied.
The individuals resemble in form, in the
number of their delicate tentacles and in
their soft anterior body, the other living
members of the order. In the structure of
their skeleton they are, however, unique
among extant corals, and recall certain
extinct forms. Each individual secretes
a smooth-walled tube, without calcification
of the vertical septa. These tubes, which,
like the pipes of an organ, stand almost
parallel, are united to form a stock by
means of transverse platforms. These
latter do not, however, correspond with

RED CORAL.

1, Part of a stock with retracted polyps, two have
been opened (magnified) ; B, With polyps more
or less extended ; a larva (a) seen in the act of
emerging through the mouth of the uppermost
polyp.

organ-pipe coral, Tubipora (nat. size).

a, Starting points of new individuals
(nat. size.)

the inner transverse parti-
tions (tabvlce), by means of
which the upper living part
of the tube is from time to time cut oft' from the dead part below. The
transverse platforms are neither regularly parallel nor continuous ; neverthe-
less they do indicate in a general way stages of growth. They are very richly
provided with nutritive canals, and are of special importance for the whole stock,
inasmuch as the young individuals bud out from their surfaces. As the longer
tubes grow, the intervals between them increase, and as soon as there is room
enough for a new polyp, one buds out from the platform. Division of the
individuals or formation of buds from the tubes themselves does lAt take place in
this family.

Coral-Reefs Having described a few typical corals, and explained their

and islands, general structure and characters, some mention must be made of the

importance of these creatures in the economy of nature. Whereas most forms of

5 1 8 CCELENTERA TES.

animal life, in passing at death into their elementary constituents, leave no visible
traces of their existence, the corals, or at least the numerous reef-making forms,
build monuments which last for hundreds of thousands of years, and may be
said to attain their greatest importance in the influence they exercise upon the
life and development of the human race. Professor Haeckel has described the
magical effect of a first sight of a shallow coral-reef, enjoyed by him on the coasts
of the Red Sea, where a long bank of coral runs parallel to the shore. The
waves break upon these barrier-reefs, the uneven edges of which lie just below
the surface of the water, and their position is thus clearly marked by the line of
surf produced. The outer side of the reef, which is exposed to the full force of
the waves, descends steeply, but the inner side, washed by comparatively quiet
water, slopes gently down ; the canal formed between the reef and the coast being
as a rule so shallow and calm that the full splendour of the garden of corals at
its bottom can be seen through the limpid water.

All reef-forming corals inhabit waters which in winter do not sink below
a temperature of 68° F., the maximum summer heat in the Pacific Ocean
being 86°. Two lines to the north and the south of the Equator, which would
connect points where the winter - temperature does not sink below 68°, waving
in and out according to the currents, would enclose the zone of the reef-forming
corals. Most of the stock - forming corals described above live exclusively
within these limits of temperature, a fact that explains their rare occurrence in
the Mediterranean, which is so favourable to other forms of animal life. The
richest coral regions lie in the middle hottest zone, that is between 15° and 18°
north and south of the Equator, where the temperature does not fall below
72° F. The Fiji Islands fall within this region, and possess reefs extraordinarily
rich in corals. The star-corals and brain-corals there reach their greatest develop-
ment, while the madrepores are found as bushes, cups, or leaves, the latter often
attaining a breadth of over six feet. In the Sandwich Islands, which lie outside
of the hottest zone, the corals are less luxuriant and varied. The genera of corals
found in the Indian Ocean and the Red Sea, as well as on the coast of Zanzibar,
are essentially the same as those in the Pacific. The corals of the Gulf of Panama,
although not in the hottest zone, have the character of the Pacific corals, and are
different from those of the West Indies.

When the two Fosters and Cook discovered the coral islands of the South
Sea, they were of opinion that the minute creatures to which these owe their
origin began to build at unfathomable depths, gradually bringing their structures
up to the surface of the water. They thus thought that the same species were
able to live at different depths. Recent researches have disproved this ; and we
now know that although many different animals live at enormous depths, all
such are specially adapted to the conditions of life at those depths. Animals
adapted to life at a great depth cannot exist at the surface. The number of
deep-sea polypi is small, and among them there are no species forming reefs ;
and authorities are now agreed that reef-building corals can only live at moderate
depths and within certain latitudes. One of the principal requirements is pure
sea-water, some species flourishing in the canals between the reefs and in the
shallower water of the lagoons, whereas others require the open sea. Corals

COXALS. 519

never flourish in impure water or on sandy or muddy coasts. They are not
found at the mouths of rivers nor in excessively salt water ; abnormal heating
of the water of the lagoons also may cause their death. The dead portion of the
stocks, and also, at times, that part which contains the living animals, suffer
continually from the action of boring-worms and molluscs, while the boring-
sponges cause still worse injuries. In addition to these foes, which tunnel
through and help to disintegrate the skeleton of the coral-stocks, other enemies
prey on the living polyps. These latter are richly provided with stinging-cells ;
and an unwary fish touching one with its lip is sure to be stung. Nevertheless,
the greediest devourers of corals are certain fish which have acquired horny
beaks like those of a parrot. These parrot-fish live by browsing on the living
flowers of the coral-garden, having jaws which are untouched by their stings.

Certain tube-dwelling worms and cirripedes (Balanus), on the other hand,
penetrate the living coral without injuring it. They attach themselves to the
surface of a coral-stock on leaving the larval condition, and gradually become
embedded in the growing stock. Some Serpulidce also grow with the stock,
their tubes reaching far into it, and their elegant crown of gills, when unfolded,
adding to its beauty

The rate of growth of various corals has been investigated by Dana and
others. Although Darwin doubts the statement that the copper plating of a ship
in the Persian Gulf was covered in twenty months with a crust of coral two
feet thick, the rapidity of their growth is proved by other observations. As
early as 1830 Allen sank a number of pieces of coral in the month of December
on a bank about a yard below the surface of the water on the coast of Madagascar,
and found, the next July, that they had almost reached the surface and had
attached themselves firmly. In Hayti a growth of three to five inches has
been observed in three months. A stock of labyrinthine brain-coral was
found to increase 11£ inches in diameter, and 4 inches in height in twenty
years. On a ship, wrecked in 1792 and discovered in 1857, a madrepore was
found which had reached a height of sixteen feet, i.e., had grown on an average
three inches yearly, whereas massive coral-stocks in its neighbourhood showed
slower growth.

The foregoing facts as to the life of the corals themselves sink into
insignificance in comparison with the results of their mode of life in the formation
of coral-reefs and islands.

Coral-reefs are banks of coral-rock in the sea along the coasts of tropical
countries. At high tide the reefs are usually under water, but at low tide are
visible as wide, flat, naked expanses of rock, just above the level of the water, in
marked contrast to the precipitous coasts of the islands they surround. At high
tide the only sign of the presence of a reef is a line of breakers, which often extends
for many miles at a distance from the land, a retreating wave only occasionally
revealing a small portion of the rock. A small island may be surrounded by such
a reef, the annexed illustration showing a typical tropical island thus encircled.
On the right side the reef forms a girdle stretching round the coast, and appears
like a continuation of the land. This fringing-reef is also found on the left side,
but beyond it, separated by a channel, is the barrier-reef. At one point the land

S20

CCELENTERA TES.

is seen to dip down precipitously into deep water, and here, on account of the
depth of water, the reef is wanting. The barrier-reef also is broken through at
one point, forming the entrance to a harbour, such as is often found in reef-
surrounded islands. Many islands are bordered by a reef which protects the
land from the sea like a mole. The barrier-reef may occasionally be ten or fifteen
miles from land, and enclose several high islands. Various forms of reefs are
found between the two extremes presented by such a barrier-reef and the simple
fringing-reef.

The channel within the reef at low tide is sometimes hardly deep enough for
navigation, or else it is blocked by masses of coral which render its passage
dangerous. At other times a reef encloses miles of open water, ten, twenty, or
forty fathoms deep, but not free from hidden sources of danger ; masses of living
coral, from a few square feet to several square miles in extent, rising from the
bottom. In the Fijis all these kinds of channel formations occur.

The extent of the reefs, which include scattered banks and masses far below

ISLAND WITH FRINGING- AND BARRIER-REEFS.

the surface of the water, varies greatly. On some coasts there are merely
scattered groups or mounds of coral-rock, the tips of which project as rocks;
while, on the other hand, to the west of the Fijis there is an area covered with
reef of about three thousand square miles. Other reefs are one hundred or one
hundred and fifty miles long, and the Australian barrier-reef attains a length of
one thousand two hundred and fifty miles.

Passing from such a tropical island girt with coral-reefs, we come to what is
more especially known as a coral-island proper, or atoll, which may be described as
the encircling reef without any island to encircle. It surrounds a calm lake of
blue water, in striking contrast to the restless ocean outside the solid circle. The
ring of solid reef in this case is usually only one hundred to two hundred yards
broad, and at some parts so low that the waves break over it into the lagoon. At
other parts it is covered with tropical vegetation, but it rarely rises more than
three to four yards above high-water mark. Seen in the distance from a ship, a
coral island looks like a row of dark points, which are the tops of the cocoanut-
trees first seen above the horizon. On nearer approach, the lagoon with its green
border is a wonderfully beautiful sight. Outside of the reef is the heavy surf, and
within the white coral strand, the thick band of verdure, and the enclosed lake with
its minute islands. In colour, the water of the lagoon, where it is deep (ten to

CORALS.

521

twelve fathoms), matches the blue of the surrounding ocean, but delicate apple-
green and yellow tints mingle with the blue wherever the sand or coral-rocks
approach the surface. Although the girdle of reef covered with vegetation
occasionally surrounds the lagoon, it is more often broken up into a ring of
separate islets of various sizes; between some of which navigable channels are
found, giving admittance to the lagoon.

The submarine fields of living coral spread along the coasts of the islands and
the mainland. Just as the accumulated remains of the primitive forests add layer
after layer to the soil, so the coral-reefs are added to by the breaking down of old
corals, by the shells of bivalves and of other organisms. These fragments keep filling
up the spaces between the separate living stocks, so that the level of the reef is
constantly rising towards the surface. The currents and waves also take part in
the building up of the reef. Masses of coral of all sizes, from great boulders to
minute sand grains are broken off' by the waves, and are cast upon the reefs, and
then rolled about until quantities of fine detritus are produced, which, as calcareous

CORAL-ISLAND OR ATOLL.

mud, serves as a cement to bind the larger blocks together. A constant process of
destruction goes on ; some of the detritus being washed over the reef into the lagoon
or canal, and some filling the spaces between the corals along the edge of the reef,
while the rest remains upon the surface.

The layer of dead coral-rock forming the foundation of the reef is bordered
by living coral. While this living coral is always extending the reef horizontally,
the waves are piling up the dead masses vertically, till they rise above the surface
of the water. Thus dry land begins to form, and by degrees islands arise well out
of the reach of the waves. The ocean is thus the builder of the coral-island as it
appears above the waves, the material having been supplied in the first place by
the coral-animals. The moment the island is above water, plant seeds reach it from
distant lands, and ere long cover it with vegetation. The accompanying section
of a coral-reef shows the slope of the reef, both towards the lagoon on the
right and the open ocean on the left. At b-c is the steep slope from shallow
water to the land level on the outer side, and at d-e the gradual slope on the
inner side. The latter slope is then continued at almost the same angle {e-n),
the quiet water not disturbing the slow accumulation and growth of the lagoon or
canal shore. On the outer side of the reef, however, a broad terrace (a-b), succeeds

522

CCELENTERA TES.

the steep slope, and surrounds the land which has risen above the sea, this terrace
being exposed at low tide.

We have still to mention some of the causes of modification in the form and
growth of the coral-reefs. The presence of harbours in reefs and atolls can, as a
rule, be traced to the tides and to local ocean currents. There is generally an
outflow through the canals and openings in the reefs. This is apparently due to
the fact that water is constantly being thrown by the larger waves over the lower
portions of the reef into the canal or lagoon, and seeks either to escape as an under-
current in opposition to the flood-tide, or else strengthens the ebb-tide. These and
other similar disturbances of the water in the canals bring with them much coral
detritus, and render the bottom altogether unsuitable for the growth of corals.
Where such currents are strong, they keep the canals clean and open. The action
of the oceanic currents is often increased by the fresh waters coming from the
central islands, and harbours are therefore very often found at the mouths of
valleys and of their small streams. The influence of the fresh water itself on the

SECTION THROUGH A CORAL-REEF.

corals is not so great as is usually assumed, chiefly because it, being lighter than
salt water, flows awa}7- on the surface of the latter and hardly touches the animals
which grow below the surface.

The form of the reef is again largely influenced by the form and constitution
of the sea-bottom. Where deep submarine fissures occur, dipping down below the
level at which the corals flourish, no reef can be formed, as also in places where
firm ground alternates with sand and mud. All irregularities in the outline of a
reef or an atoll, and the formation of harbours in coral islands, can thus be simply
explained.

The most important point which needs elucidation is why some reefs encircle
islands as a fringe extending from the shore, while others run parallel with the
land, no longer touching it ; others, again, forming circular lagoons with no island at
all in the middle. This was the question which puzzled the first discoverers of
reefs, and at one time it was supposed that instinct guided the animals in giving
their structures the form best suited to withstand the force of the waves. Accord-
ing to another hypothesis, put forth by Steffen in 1822, the reefs represent the
summits of volcanic mountains, the crater being filled by the lagoon, while the
channels through the reef indicate the points at which the edge of the crater was
destroyed by outbursts of lava. This superficially plausible view was disposed of
by Darwin thirty years ago. He argued that the volcanic cone thus assumed must
either once have stood upon dry land and then have been submerged, or else must
have been formed beneath the sea. In the former case, the crater would in almost
all cases have been destroyed during the gradual sinking ; while the formation of
craters by submarine eruptions and their subsequent elevation is hardly conceivable.

CORALS. 523

This hypothesis further requires the assumption that immense numbers of volcanoes
must have arisen over a limited area, and a still more improbable supposition, that
all these volcanoes rose to almost the same level, seeing that the coral animals
occur only within a depth of about twenty fathoms. Craters nearly fifty miles in
diameter must be assumed to have existed, and others of twenty to twenty-five miles
must have been frequent. For these and other reasons, the volcanic origin of coral-
reefs was rejected. It is obvious also that the same objections dispose of another
hypothesis, namely, that nonvolcanic summits and banks of equal height were the
foundations on which corals built.

Darwin believed that all forms of reef arise by the gradual sinking of the
land they surround. This theory has been confirmed in all essential points by
Dana, and recently by Langenbeck. Other authorities have, however, differed.

The condition of the reefs attached to the Fiji Islands illustrates Darwin's
theory of subsidence. The Goro Reef lies close to the land along whose submarine
coast it grows. The Ango reef is of the same nature, but lies further from
the land, having a channel between it and the shore, and forms what is called
a barrier-reef, which name denotes merely difference of position, not of kind.
The barrier-reef of the island of Nanuku encloses a large stretch of sea, the
islands within it being nothing else than the rocky summit of a mountain.
Darwin's theory gives an explanation of these differences. If, for example, the
island of Ango were very gradually to sink, two things would happen, — the island
would disappear little by little, while the reef would remain at the surface of the
water, that is, so long as the land did not sink faster than the corals could build.
When the subsidence had gone so far that only the last mountain summit remained
above water, the condition found in the island of Nanuku would be realised.
Instances are also found in the Fiji islands of the intermediate stages, where only
a single mountain ridge and a few isolated peaks remain above water.

It is a known fact that large countries, such as Sweden and Greenland, are in
the act of sinking, and we also have direct proofs that reefs and their islands have
subsided. The depth of a reef, although not directly measurable, can be approxi-
mately estimated, and must in many cases be at least three hundred yards. Since
the living portion of a coral-reef cannot reach more than eighteen to twenty fathoms,
such a depth of reef can only be explained by the sinking of the land on which it
stands. If, instead of sinking, the land rises, the reef would be lifted out of water ;
raised reefs three hundred feet high being known. This enormous thickness of reef
can hardly be explained without a previous subsidence, inasmuch as such a height
is greater than the known depth at which corals can live. The assumption that
many reefs are the consequence of simple subsidence thus appears highly
probable.

The accompanying diagrammatic section (p. 524) through an island and its reef
illustrates the action of gradual subsidence. The island at the water-line (I) has a
simple fringing-reef (//), a narrow rocky terrace at the level of the water, which
first descends very gradually and then more steeply. Supposing the island to sink
to the level (II), what would happen ? While the land has sunk, the reef has risen,
and there is a fringing-reef (/') and a barrier reef (b), with a narrow channel (e')
between them. A further subsidence to level (III) greatly increases the width of

524

CCELENTERA TES.

the channel {e"). On the one side (/*), the f ringing-reef is retained, while on the other
it has disappeared, a fact due to currents and other such agencies. Finally, when
the water is at the level (IV), two rocky islands are visible in a large lagoon
surrounded by the reef (b'" h'"), with two small reef-islands (%" %") developed on

DIAGRAM EXPLAINING THEORY OP SUBSIDENCE.

mountain-peaks which have disappeared below the surface. The coral-rock has
greatly increased in thickness, and almost entirely covers the former island.

Such an ideal section corresponds exactly with the reality. In the following
illustration the outline of the island of Aiva, one of the Fiji group, is given. In
the lagoon there are two islands resembling the summits of mountains, just as in
the diagram. The exact altitudes and depths are unfortunately not known, but it
will be seen how well the theory of subsidence appears to explain the conditions.

The chief objections which have been made to this theory of subsidence are

OUTLINE OF THE ISLAND OP AIVA, WITH PROJECTED SECTION.

the following. The simultaneous occurrence of atolls, barrier-reefs, and fringing-
reefs in neighbouring regions does not coincide with the theory, nor does the
appearance of atolls and barrier-reefs in regions in which recent elevation of the
land has been proved. The discovery of extensive submarine banks of sediment
formed of the calcareous portions of foraminifera, deep-sea corals, molluscs, etc.,
makes it possible to explain the formation of atolls and barrier-reefs without the
help of subsidence, this explanation being more probable than that involving the
sinking of extensive areas of land. The formation of atolls can be explained by

CORALS. 525

the better growth of the corals on the outer edges of the reef which are most
exposed to the action of the surf, and the sweeping of the coral material out of the
lagoon through the agency of oceanic currents, and the dissolving action of the
carbonic acid contained in the sea water. The deep canals which divide the
barrier-reel's from the neighbouring mainland are formed in the same way. The
enormous magnitude of the reefs which the theory of subsidence demands is
nowhere realised. Neither among modern reefs nor among geological formations
do we find any traces of such gigantic masses of coral-rock. We are thus in
face of a fascinating and important scientific problem, which still remains to
be solved, a problem which was long thought to have found its solution. After
Darwin's and Dana's subsidence theory had been generally for many years
accepted as beautiful and completely satisfactory, we are told that it is not
always applicable, and that much simpler causes suffice to explain the phenomena.
It is obvious, then, that we have an ample supply of possible explanations of
coral-reefs, and it is most probable that among the many scattered reefs in the
world, in one case one set of factors have played the chief part, in another case
a slightly different set, and further, a detailed and exhaustive study of any
particular reef would probably reveal natural processes of no small importance
which have not as yet been taken into account.

H. and M. BERNARD.

MOUTHS OF MADRETORE.

Characteristics.

CHAPTER XV.

The Sponges, — Suhkingdom PORIFERA.

There are about two thousand species of sponges known, which
range in size from a pin's head to masses several feet in height,
and vary in weight from a grain to over a hundred pounds. They assume an
endless variety of shapes, such as cups, vases, spheres, tubes, branched tree-like
growths, etc., but are often shapeless. When alive, they are of all colours, and
their consistency may be soft and glutinous, fleshy, leathery, or stony. They are
found in all seas, and in all depths from the shore margin to several miles deep,
and certain species occur in fresh waters all over the globe. About three hundred
species have been found round the coasts of Britain. Aristotle was the first to
give a scientific account of sponges. He considered that they were either animals,
or organisms transitional between plants and animals, and that they possessed
sensation, since they shrank when torn from the rocks. He classified the kinds
then known, and asserted that the animals often found in the cavities of sponges
were intruders, and did not make the sponges; further, he distinguished the

BREAD-CRUMB SPONGE, SHOWING CURRENTS ENTERING SURFACE AND LEAVING BY OSCULES.

large holes on the surface of certain species from the small ones, and thought that
water was sucked in by the former.

From the time of Aristotle till 1762 little was recorded, but in that year
Ellis published his observations on the bread - crumb sponge, a British species
forming fleshy masses or crusts of a yellow or greenish hue. This sponge envelops
the stems of seaweeds, or encrusts rocks and stones ; when growing on seaweeds
it forms cake-like masses with a level surface, but when encrusting rocks the
surface is covered with small cones resembling miniature volcanic craters. The
surface between the craters exhibits a very fine gauze -like pattern; and, by

CHAR A CTERISTJCS.

5*7

careful inspection, groups of minute pores will be seen perforating the meshes.

The large holes at the summits of the craters are termed oscules, and the small

ones on the general surface, pores. Ellis, who put some specimens in a glass

vessel of sea water, wrote that " We could plainly observe) those little tubes to

receive and pass the water to and fro " ; and further, " The sponge is an animal

whose mouths are so many holes or ends of branched tubes opening on its

surface; with these it receives its nourishment, and by these it discharges like

the polyps its excrement." Ellis's observations were erroneous in one important

point. The water always passes

out of the large orifices, and is

not passed in by them. It is

true that while the torrent is

gushing out of the centre of an

oscule, there is a slight passive

return current at the margin.

Ellis attributed the current to

the contraction of the walls of

the canals. He found that the

current continued in the absence

of any worms or crustaceans in

the body of the sponges.

Our knowledge of sponges
really begins in 1825 with the
observations of Grant, who ex-
amined a fragment of a living
branch of a branching -sponge.
On bringing one of the large
apertures on the side of the
branch fully into view, he
beheld this living fountain
vomiting forth from a circular
cavity a torrent of liquid matter,
and hurling along in rapid
succession opaque masses, which
it strewed everywhere around.
After many experiments, Grant convinced himself that a current flowed out of
all the large orifices, and not into one and out of another. He also rubbed
powdered chalk on the surface of a bread-crumb sponge, and saw particles which
clogged the margins of the minute pores on the surface driven into the interior ;
and thereby demonstrated the passage of currents into the interior through
the pores. The origin of the sponge-fountains was now traced. In all sponges
currents of water pass into the body through pores, and out again by one or
more ways different from those by which they entered. To ascertain the cause
of the currents, it is necessary to examine the anatomy of the sponge. A thin
skin, which can be peeled off, is separated from the body by numerous minute
supporting pillars. On cutting into the sponge, large canals are seen passing down

«, FLAGELLATED CHAMBER OF BREAD-CRUMB SPONGE, SHOWING COLLAR-
CELLS ; b, FLAGELLATED CHAMBER OF FRESH-WATER SPONGE.

(Both figures 1600 diameters. ) — After Vosmaer.

528

SPONGES.

from the oscules and branching into the body, and much narrower canals from
the groups of pores in the skin. The channels from the pores divide up into
minute lacunar spaces, or canaliculi, which finally communicate with the interior
of small, spherical, flagellate'd chambers, whose walls are perforated by pores.
Each of the chambers is the five-hundredth of an inch in diameter, and groups

sponges growing on seaweed, a, b, Two of the Desmacidine group ; c, Spongeldia. (Nat. size.)

of them open each by one wide orifice into a common space, or canaliculus, which
joins with others to form canals terminating in large oscular canals.

The walls of the canals are lined with flat-cells, but in the flagellated
chambers the lining cells are more or less cylindrical, and each is provided at its
free end with a whip-like appendage, or flagellum ; and, further, the upper margin
is expanded into a thin hyaline collar, so that the whip appears to rise from

CHAR A CTERISTICS. 5 2 9

the centre of a basin or funnel. The currents of water traversing the body of
the sponge are kept up by the movements of the flagella of the collar-cells. The
flagella beat the water in the flagellated chambers into the rootlets of the canals
leading to the oscules. To replace this, water flows into the flagellated chambers
from the rootlets of the canals passing down from the groups of pores in the
skin. The currents entering the sponge bring in oxygenated sea-water, and
minute food particles such as diatoms, infusoria, etc ; the currents from the
oscules contain an excess of carbonic acid, of waste products resulting from vital
activity, and indigestible remains. The cells lining the canals effect the exchange
of gases, and take up food-particles.

At present, too little is known as to the physiology of digestion in sponges,
to permit of any definite statements being made. In some sponges, which have
been fed with carmine granules and then killed, the collar-cells have been found
loaded with granules ; in others, again, the flat cells lining the subdermal cavities
have been found gorged with the carmine. A terminal cluster of flagellated
chambers in the bread-crumb sponge may be compared to a hollow mulberry,
reduced to its skin but retaining its shape ; each swelling represents one
flagellated chamber, opening by one wide orifice into the common central space'
which is continued into the stalk. A grape-like cluster of mulberries would
convey some idea of the arrangement of the canals, in which the hollow main
stem represents the terminal oscular canal. Further, each swelling on the surface
of the mulberry is perforated by several round pores, termed prosopyles (en-
trances). Another call on the reader's imagination must now be made. The
openings of the infoldings on the surface are closed over by a membrane
perforated by pores. Suppose the mulberry cluster to be immersed up to its stalk
into a skin-bag of jelly, and the skin to be tucked in and folded so as to form
channels or canals branching and diminishing in size, till they abut on to the
surface of the mulberries. Again, suppose the bag to be immersed in water which,
by some means, is made to enter the walls of the bag and come out at the stalk.
The current will pass from the pores in the skin, then along the channels till it
reaches the pores or prosopyles on the surface of the mulberries, through which
it passes, and proceeds to the stalks and main stem. The system of canals from
the skin pores to the prosopyles is termed incurrent, and that from the cavities
of the mulberries to the orifice at the top of the stem out-current. This structure
is shown in the illustration, but the representation is extremely diagrammatic.
In a thin section of Halichondria one sees a labyrinth of in-and-out-current
canals and spaces together with small flagellated chambers; of the latter, often
only one or two open into an out-current space or rootlet.

The jelly mass, which in the model supports the hollow mulberry cluster and
the channels from the outer skin, would of itself form an inefficient support, so we
must add to it a scaffolding of rods and bars or tough horny fibres ; the common
bath-sponge skeleton, and the skeleton of the Venus' flower-basket are the horny
and flinty scaffoldings supporting the soft tissues together with the flagellated
chambers and the channels which lead to and from them in the living sponges.
The fleshy or jelly substance of sponges is termed mesoderm (middle layer),
because it is situated between the collar-cells, which constitute the endoderm

vol. vi. — 34

53°

SPONGES.

(inner layer), and the layer of cells on the outer surface, or ectoderm (outer
layer). The usually flat cells of the ectoderm are now considered to be
simply a superficial layer of mesoderm cells, and not to constitute a special

carpenter's glass-sponge, Pheronema (nat. size).

separate layer distinct in itself. Whether this be the case or not, the terms
mesoderm and ectoderm may be conveniently retained here. The ground-
substance, or mesoderm, contains cells of various kinds, namely, irregularly-shaped

CHAR A CTERISTICS. 53 1

cells with slender branching processes, which unite with those of other cells to
form a network ; wandering amoeboid cells, probably concerned with digestion,
distribution of nutriment, and excretion; skeleton-forming cells, which secrete
lime, or flint spicules, or horny fibres ; contractile muscle-cells, possibly nerve-
cells ; and, lastly, male and female reproductive cells. The cells with the slender
processes secrete the gelatinous ground-substance, which may be compared to the
material forming the umbrella of jelly-fish.

The varying consistency of sponges, which may be soft, stony, leathery, horny,
etc., results from the amount and kind of material secreted by cells of the mesoderm.
In the Venus' flower-basket, these cell architects form large spicules of silica which
are joined into a trellis. In the living bath-sponge, groups of cells congregate in the
ground-substance, and secrete a network of cylindrical fibres of horny material. In
calcareous sponges, the skeleton-cells form spicules which nearly always remain
separate, and are always beautifully adapted for purposes of support. In addition to
forming a support, the skeleton spicules, in many cases, afford a means of defence
against small animals by forming spikes in the canals, or on the surface ; and, further,
it is improbable that any fish would repeat the experiment of eating a siliceous sponge.

To return to the bread-crumb sponge. A dried specimen can easily be
crumbled into powder, in which can be seen numerous glassy spicules, pointed at
each end, and about an eightieth of an inch in length. The spicules, which are
unaffected by most of the strong acids, are composed of silica, and are allied in
composition to flint and opal.

Each needle is made up of concentric laminae of silica, deposited round a fine

central axial canal containing a thread of organic matter, and each is formed in

a cell of the mesoderm. In this sponge the needles are separate, and scattered

with scarcely any regularity in the ground-substance, excepting at the surface,

where bundles of needles are joined by their ends to form the gauze-like network.

In many sponges the rods or bundles of rods form a regular scaffolding.

As regards the modes of reproduction, both male and female
Reproduction. . *

cells are found in the mesoderm, either in the same or in different

specimens. The male cells in sponges generally give rise, by division of the

nucleus, to masses of spermatozoa, each of the latter possessing a conical head

and a long vibratile tail. The ova appear as large rounded cells, which, after

fertilisation, undergo segmentation or division, first into two cells, and each of

these again into two, and so on, until a mass of cells results, two kinds being

present, one forming an outer layer covering the other. The outer layer of the

now egg-shaped embryo, excepting at the narrow end, is composed of long,

narrow, cylindrical cells, provided with cilia; and the inner mass is composed

of large granular cells. The embryos appear as minute oval bodies, about the

size of a pin's head. If a bread - crumb sponge be cut open in the autumn,

they will be seen as bright yellow spots in the body-substance. By keeping

specimens in a vessel of water, and examining them daily, the embryos will

be observed being driven out of the oscules, and swimming about with the broad

end forwards. After from twenty - four to forty - eight hours of independent

roving existence, an embryo fixes itself by its broad end, and becomes flattened.

By a remarkable transformation peculiar to sponges, the large granular cells of the

532

SPONGES.

interior burst out and grow over the outer flagellate layer of cells, and the latter
become the collar-cells of the adult sponge. A minute sponge with one oscule
results from the development of the fertilised ovum. An extensive crust with
numerous oscules may be regarded either as a colony in which each oscule

represents an individual, or simply as one individual
in which the growth of the body necessitates the
formation of new channels for the conveyance of
food materials.

We are now in a position to answer the question,
What is a sponge ? It is obviously a living animal
organism. The next question — the position of
sponges in the animal kingdom — is not settled. All
are now agreed that sponges come somewhere
between the Protozoa and the rest of the animal
kingdom, or Metazoa. It is accepted that sponges
cannot be classed with Protozoa, for the embryo
consists of definite groups of cells giving rise to
distinct tissues. Some zoologists class sponges with
opinion here adopted is that sponges form a special

SKCTION OF WALL OF VENUS' FLOWER-
BASKET, SHOWING SOFT PABTS. —

After F. E. Schulze.

the Ccelenterata. The
subkingdom — Porifera.

The bread-crumb sponge lias been selected as an example for explaining the
nature of sponges, because of the historical facts associated with it, and its
occurrence round the British coasts. Its anatomy is, however, somewhat com-
plicated ; but there are other simple forms, the study of whose structure renders
it possible to trace the path of development along which the more complex forms
have proceeded. One of the simplest of sponges
is Ascetta primordialis, found on seaweeds
in the Mediterranean ; in its simple unbranched
condition it forms a minute white sac about a
twenty - fifth of an inch in height, opening
above by a wide round oscule, and narrowing
below to a stalk. The walls are very thin and
perforated by pores, through which water
passes into the interior. The walls of the sac
are composed of two layers, an inner lining of
collar-cells, and an outer layer, consisting of a
gelatinous matrix containing amoeboid cells and
transparent three -rayed spicules of carbonate
of lime. A canal-system can hardly be said to
have arisen since the walls of Ascetta are thin A}
and not folded. The spicules support the walls
and serve as a framework for the pores. By

eliminating the spicular skeleton, and by supposing the tube or vase to be
more globular, we obtain the " olynthus - form " which has been regarded as the
hypothetical ancestor of all sponges. A canal-system arises when the walls grow
thick or form folds or give off pouches or tubes. The folds or pouches may

Magnified
Transverse section
nified 700 times. )

AN ASCON SPONGE.

20 times ; B, 80 times

D, Collar cells.

C,

(Mag-

CHAFA CTERISTICS.

533

be so close to one another that the spaces between and outside of them form
channels, which arc incipient in-current canals, the spaces in the inside or lumen
of the folds forming the out-current canal-system.

The common ciliated sycon, a calcareous sponge found on seaweeds round the
British coast, forms a white sac about an inch in height, and with a crown of
glassy bristles round the orifice. The vertical cavity of the sac is surrounded by a
wall of closely packed horizontal tubes, opening at their inner ends into the central
cavity, but externally ending blindly. The central cavity of the sac is lined with
flat-cells, and the radial tubes with collar-cells; and the walls of the tubes are
perforated with small pores. Here the spaces between and outside the densely
packed tubes are the in-current canals. In an equally common British sponge,
Grantia, which forms small flat white bags, a rudimentary cortex covers the
outer ends of the tubes. In Grantiopsis the cortex becomes quite thick. In
more complex stages the radial tubes branch ; and, finally, the collar cells clothe
only the ends of branched tubes, thus giving rise to more or less spherical
flagellated chambers. As the radial tubes become more branched, and the

TOILET-SPONGE.

A, Diagram of canal system. />, Section showing a, pores ; b, canals ; c, flagellated chambers ; d, skeleton- fibres ;
d', main fibre ; e, embryo eggs. C, Flagellated whip-chambers. (Highly magnified.)— After F. E. Schulze.

mesoderm thicker, so the passages or in-current canals from the outside of the
sponge to the outside of the radial tubes become more complicated. Common
siliceous sponges develop in a different manner from the above-described calcareous
ones, namely, from a hollow conical sac open at the top, and with a flat base ; the
spherical flagellated chambers at a very early stage forming a mammillated layer
in the walls. Plakina, one of the simplest siliceous sponges, encrusts stones with
a fleshy crust, consisting of a sac with a flat base attached to the stone, and with the
rest of the walls forming simple folds. The spaces between and outside the folds
form the in-current, and those in the lumen of the folds the out-current channels.
Each of the flagellated chambers in the walls of the folds communicates with the
in-current spaces through several pores, and opens into the out-current spaces by
one large pore, the currents of water passing out by the central oscule.

The fine toilet-sponge possesses a more developed canal-system. The in-current
and out-current parts of the water-bearing system are more definitely " canalised,"

5^4

SPONGES.

and may be compared to the roots of a tree which divide into finer rootlets. The
flagellated chambers form a convoluted cordon between the rootlets of the two
systems. In the sea-kidney sponge of the Mediterranean the specialisation is
carried to a still higher stage, each flagellated chamber being isolated from the
rest, and having a slender canal leading to it, and one leading from it.

The soft tissues permeated by canals require a supporting scaffolding or
skeleton, and in nearly all sponges it is the function of certain cells in the
mesoderm to secrete skeleton-material. A few sponges possess no skeleton
whatever, excepting the gelatinous ground-substance; in some also the skeleton
is mainly or entirely composed of foreign particles of sand, spicules of other
sponges, skeletons of Radiolaria or Foraminifera. The vast majority form in
the ground - substance a skeleton which is composed of spicules of silica, or
carbonate of lime, or of horny fibres. The sponges whose skeleton is composed
of calcium carbonate form a distinct class — the Calcarea. Of those which secrete
a siliceous skeleton, the glass-sponges form a second class distinct from the rest
of the siliceous sponges. All the rest, including by far the largest number, are
included under a third class, the common sponges (Demospongia).

t The Calcareous Sponges, — Class Calcarea.
In this group the skeleton is formed of spicules of carbonate of lime, shaped

a calcareous ascon sponge, LeucosoUnia (magnified 4 times).

like three-rayed stars, four-rayed stars, or needles. The triradiate occurs most
frequently in its typical form, the three rays being equal, in one plane, and forming

CALCAREOUS GROUP. 535

an angle of 120° with each other. The spicules are transparent and glassy when
viewed separately, but white and opaque in mass. On placing a calcareous sponge
in acid, the skeleton dissolves away with effervescence. The class is divided
into two groups, namely, the Homocoela and the Heterocoela, in the former of
which the collar-cells line the whole of the interior of the simple or branched
sac; while in the latter they are confined to the radial tubes, or the ends
of branched radial tubes or canals, the gastric cavity with a part of the
canal system being lined with flat cells. The simple ascon sponge (Ascetta
primordialis) forms a minute stalked sac open above, and with its thin walls
perforated by pores and supported by triradiate spicules ; the whole interior being
lined with collar-cells. The simple sac may give off a stolon, whence arise other
sacs, or it may branch, and the branches again divide forming a tree-like growth ;
or, lastly, the branches may join together and form a complicated meshwork of
sacs or tubes. The allied Leucosolenia, shown in the illustration, is a branched
ascon found on seaweeds in the form of clusters of small white tubes.

The ciliated sycon (Sycandra) and Grantia, are common among seaweeds and
in rock-crevices on the British coasts; both sponges are sycons, i.e. with tubes
radiating out horizontally from a central cavity, and in
both are present the three kinds of calcareous spicules
(needles, three-rayed, and four-rayed forms). The walls
of the ciliated sycon are made up of closely -packed
tubes, lined with collar-cells and opening into the vertical
gastric cavity. Rows of three-rayed spicules, arranged
in regular series, support the walls of the tubes, the
blind ends of which are protected by tufts of needles ;
a layer of four-rayed spicules lines the walls of the
central cavity, the fourth rays projecting inwards
and upwards into the cavity so as to form a wall
of spikes. When the current is flowing from the
interior the crown of needle bristles round the oscule Leucandm (nat. size).

is expanded, but when the sponge is inactive the

bristles fall together and cover the oscule. Grantia lives on seaweeds or
hanging down from rocks, and several specimens are usually found together.
They resemble small white leaves, or flat bags, averaging about an inch in
length and one and a half in width, though sometimes much larger. When
quite young and small they possess only one oscule, but larger specimens possess
several on the thin margins. When the sponge is active, the flat leaf fills out like
a small paper-bag. The leucons usually possess tubular or hollow knob-shaped
bodies with thick walls, in which ramify a double system of canals, in-current
from the surface to the flagellated chambers, and out-current from the latter to the
gastric cavity.

On making a section or teasing a fragment of a calcareous sponge in the
spring, the minute embryos will often be seen. When the embryo leaves the
parent sponge, it consists of an extremely minute oval cyst or vesicle (v) wTith a
small central cavity, and is formed of two kinds of cells. The anterior half, or the
part in front when the embryo is swimming, is composed of a number of long

536

SPONGES.

prismatic cells, each carrying a vibratile flagellum. The hinder end is composed of
a smaller number of large rounded granular cells without flagella.

After the larva has swum about for a time, it becomes broader in the
equatorial zone (6). The fore-half broadens out more and more till it forms a
flat lid on the hinder hemisphere. Finally, the small cells lose their cilia and
become completely invaginated into the interior of the large-celled hemisphere,
which now resembles a cup with a double wall (c).

There are thirteen British species of Calcarea, and over two hundred from all

development OF Sycon raphanus (all figures enlarged).

parts of the world. They are almost confined to shallow water, the greatest depth
from which they have been obtained being four hundred and fifty fathoms.
Calcareous sponges prefer shade and avoid light, and are chiefly found in caves,
under stones, in shells, or in the shade of dense thickets of seaweed.

Six-Kayed, or Glass-Sponges, — Class Hexactinellida.

In the sponges of this group the skeleton is built of spicules with three axes
and six rays, intersecting one another at right angles through a common centre.
A second characteristic consists in the comparatively simple arrangement and large

GLASSY GROUP.

537

size of the thimble-shaped flagellated chambers, which attain an average length
of 2^0 of an inch in Euplectella. Leaving out of consideration the skeleton, the
soft tissues typically form a tubular sac open at the top, and, with the walls, formed
of five layers, an outer dermal and an inner gastral membrane with a layer of
flagellated chambers suspended between and supported by subdermal and sub-
gastral networks of fibres; the direction of the water current being always from the
dermal to the gastral surface. The six-rayed spicule is the form best adapted to

SILICEOUS SPICULES OF SIX-BAYED, OR GLASS-SPONGES ; IN THE CENTRE AN EIGHT-SIDED INTERSECTION
NODE OF A FOSSIL VENTRICULITE SPONGE.

support a soft walled sac of this description, one axis being vertical to the walls,
and the other two tangential ; the rays of each spicule uniting with those of adjoin-
ing spicules to form a framework. The typical spicule has six equal rays at right
angles to each other, with an axial canal in the centre of each. When four of the
six rays disappear, leaving only a glassy rod, the history of such a spicule is
betrayed by the presence of a minute cross, which is all that remains of the axial
canals of the atrophied rays. Endless modifications of the typical form may occur.
One or more of the six rays may develop more than the rest ; one or more may be

538 SPONGES.

suppressed, resulting in the formation of five-, four-, three-, two-, or one-rayed
spicules. Again, the simple principal rays may branch or give off tufts, which may
be pointed or end in discs. Further, the rays may be curved, or become beset with
spines. The spicules either remain loose and separate in the soft tissues or become
joined by apposition and intertwining, or by fusion of rays by means of layers or
bars of siliceous cement.

The glass-sponges are divided into two groups, the Lyssacina and the
Dictyonina. In the former the spicules are loose and separate, fusion when
present occurring in the older parts of the sponge ; in the latter the principal
spicules form a solid framework even in the earliest stages of growth. Bathydorus,
a Lyssacine sponge, which has diverged but slightly from the simple sac form, was
dredged from two thousand nine hundred fathoms in the North Pacific, and forms
a soft thin-walled tube about seven inches in height and two inches in diameter.
In the Venus' flower-basket (Euplectella), shown in the central illustration of the
coloured Plate, there are certain modifications of the simple sac type. Firstly,
there is a lid at the top, and further, the walls of the tube are perforated by large
round holes about one twenty-fifth of an inch in diameter. The water can thereby
pass direct from the outside into the gastral cavity or lumen of the tube ; each
aperture is surrounded by an iris-like membrane which can probably close the
orifice. These parietal apertures, in the whole thickness of the wall, must not be
confused with the very minute in-current pores through which the water passes
into the sponge-substance. In life, the glassy framework — frequently seen as an
ornament — is covered with the brownish gelatinous flesh. The glassy skeleton
forms a curved tube from 10 to 18 inches in length, shaped like a cornucopia,
the curve taking place at the junction of the lower and middle third. Euplectella
oweni from Japan, which closely resembles E. aspergillum, forms a straight
cylinder, devoid of the collar round the lid and without ridges on the walls.

The glass-rope sponge (Hyalonema) of Japan belongs to a group of Lyssacine
sponges, characterised by the possession of amphidiscs, spicules with a straight
shaft, at each end of which is a large toothed disc, resembling the ribs of an
umbrella. The spicules are sometimes large enough to be visible to the naked eye,
and vary in different species from the hundredth to the twenty-fifth of an inch
in length. The rope was first brought to Europe about 1830, and for years
formed the subject of controversy as to its nature. The Japanese glass-rope
sponge forms a solid-looking, ovoid, thick-walled cup, the top of which is closed
by a thin sieve-like lid with an imperforate cross-shaped area. From the lower
end of the body arises the long siliceous glass-rope, composed of twisted strands
of spicules which anchor the sponge in the mud. For a varying distance below
the body, the tuft is invested by a parasitic zoophyte. A transverse section of
the cup shows a cavity, in the centre of which is a spike which is the upper
end of the glass-rope projecting into the interior. From the central spike septa
radiate ; these are convex along their upper margins, and attached at their
ends to the imperforate bands on the operculum. The walls contain the much-
folded layer of flagellated chambers.

The spicules of the tuft are pointed at the upper end, and terminate below in
minute four-pronged anchors. Many of them are marked with a spiral ridge,

GLASSY GROUP. 539

minutely serrated on the upper edge, and thereby offering resistance to the uproot-
ing of the tuft from the mud. The length of specimens varies from 20 to 30
inches.

The Japanese species is obtained from off Tokyo, from a depth of three hundred
and forty-five fathoms, and is fished for with long lines, weighted and provided with
hooks, which are dragged along the bottom. Eighteen species have been obtained
from the Atlantic, Pacific, and Southern Oceans, from depths ranging from a few
hundred up to two thousand five hundred and fifty fathoms. The allied Semperella,
shown in the right-hand illustration of the coloured Plate, occurs in one hundred
fathoms off the Philippines. It forms a subcylindrical stock, about 12 inches in
length and 2 inches thick, terminating in a dense tuft about 3 inches long. The
lace-like skin covers a complicated labyrinth of tubes. Another Philippine form
(Polylophus), represented in the bottom right-hand corner of the same Plate, has
small thick-walled hemispherical cups, with tufts of spicules growing from conical
projections on the walls, and passing down to form root-tufts. This sponge is
remarkable for producing buds, which become detached and develop into complete
sponges. In the middle of the lower part of the Plate is shown a species of another
genus, known as Periphragella, from Japan, which forms a curved funnel, on the
outer wall of which is a network of tubes which have branched off from the main
body. In Farrea, seen in the left-hand bottom corner of the Plate, the body is
formed of forking branched glassy tubes, the walls of which consist of spicules
whose rays have fused into a rigid framework. Sclerothamnus, from three
hundred and sixty fathoms off Timor, is a remarkable Dictyonine sponge, which
forms a bush two or three feet in height, with the branches marked with a spiral
band.

Another beautiful type is Carpenter's glass-sponge (Pheronema), shown in the
illustration on p. 530, which consists of a thick-walled cup, narrowed at the orifice,
and giving origin below to a thick root-tuft of spicules ; the first specimens were
dredged from a depth of five hundred and thirty fathoms off the Faroe Islands.

Glass-sponges, with one or two exceptions, have been obtained in deep water,
from ninety to two thousand nine hundred fathoms. Previous to the deep-sea
dredging expeditions, specimens had been found in only a few localities, and the
procuring of them had been due more or less to accident. Thus the Japanese
fishermen, while in quest of deep-sea fish, brought up glass-ropes, which became
marketable commodities. Similarly, the Malays found it would pay to explore
for submarine treasure, and constructed their bamboo dredge.

Fossil Hexactinellida are found abundantly in the Chalk. The Ventriculites,
found in Chalk flints, are the skeletons or casts of glass-sponges.

The Common Sponges, — Class Demospongia.

The common sponges include all those which do not come under the designation
of calcareous or glass-sponges. A negative definition is unsatisfactory, but it is
difficult to frame a positive one which will apply to all divisions of this class.
Most common sponges are siliceous, while such as are horny are probably derived
from siliceous types. They are divided into four orders. In the first or four-rayed

54°

SPONGES.

sponges the spicules typically possess four axes and four rays, and resemble
caltrops. The fleshy sponges, with little or no skeletal structure, form a second
group ; while a third group includes the monaxonid or uniaxial sponges, with the
skeleton typically built up of needle-shaped spicules, with one axis. The horny
sponges form a fourth group.

Four-Rayed Sponges, — Order Tetractinellida.

In this order the siliceous spicules of the skeleton have four axes and four
rays, and typically are shaped like caltrops. The typical form undergoes numerous

modifications, one of the commonest consisting
in the lengthening of the vertical ray, and the
bending of the other three rays towards the
long shaft, an elegant anchor -shaped spicule
resulting. The anchor form may, however, have
originated from the branching of a uniaxial or
rod-shaped spicule, and not from the alteration
of a four-rayed caltrops form. The three prongs
of an anchor may point downwards, upwards, or
horizontally outwards, and in the last case they
are frequently forked. The Lithistida (stony
sponges), one of the groups into which the order
is divided, are characterised by the presence of
peculiar spicules, known as desmas, in which a
minute rod or caltrops is surrounded by con-
centric layers of silica ; at the margin of the
plate or disc thus formed, branched and often
tuberculated processes are given off, which usually
join or interlock with those of other spicules to
form a dense stony skeleton ; but sometimes the
desmas are not linked together, and the lithistid
sponge is quite soft. In addition to the larger
forms of spicules, such as anchors, which form
the skeleton, there are minute, coiled, spiral, or
stellate spicules scattered in the flesh. A well-
developed crust is frequently present; and in
Geodia the crust is composed of solid siliceous
globules packed into a layer, beneath which lie
the anchors with the prongs next the crust, and
the long pointed shafts passing in centripetally.
The four - rayed sponges are divided into the
groups Choristida and Lithistida. In the former
the spicules are loose and separate; and in the
latter desma spicules are present, and usually
fused or interlocked so as to form a stony skeleton. The Choristida frequently form
yellowish white, leathery, nodulated cakes, plates, and crusts. The Lithistida, or

SILICEOUS SPICULES OF FOUR-RAYED ANCHOR

sponges (magnified 200 diameters).

COMMON GROUP.

54i

stony-sponges, are usually brittle and friable, or of stone-like hardness. The four-
rayed sponges belong mostly to shallow water, but a few specimens have been
obtained from depths of nearly two thousand fathoms.

The Fleshy Sponges, — Order Carnosa.

These form a small group of uncertain systematic position, their chief features
being the possession of a tough rind, enclosing a softer pith, the absence or slight
development of a skeleton, and the highly-developed canal-system. They appear to
be related to the four-rayed sponges. The soft pith contains the flagellated chambers
and the canals leading to and from them. The genus Chondrilla possesses isolated
siliceous spiny spheres, especially situated along the courses of the canals and
beneath the rind. The allied Chondrosia of the Mediterranean takes the form of

sea-kidney leather sponge {Chondrosia reniformis). a, Specimen cut open.

leathery knobs or cakes with a slimy surface. The usually solitary oscule is
irritable, and contracts slowly when the sponge is taken from the water. Fishermen
call this sponge, sea -flesh or sea -kidney. The ground -substance contains no
skeleton of silica or horny material ; and the in-current and out-current canals form
two sets of tree-like branched systems with the flagellated chambers interpolated
between the final twigs of each.

Single -Rayed Sponges, — Order Monaxonida.

These sponges are those most frequently met with on the British shores and
in shallow water throughout the world. The skeleton is mainly built up of
uniaxial siliceous needles or rods, which may be isolated and scattered, or united
into bundles by the horny cementing substance, spongin ; while the bundles may
be joined in various ways to form scaffoldings for the support of the soft parts.
The spicules are shaped like spindles. In addition to the large spicules forming
the bulk of the skeleton, and on this account called skeleton-spicules, in some
groups minute forms abound in the soft substance, and are termed flesh-spicules.
The latter are frequently shaped like buckles or double anchors, with prongs at
each end. A transition can apparently be traced from this group to the horny

542

SPONGES.

sponges; the siliceous needles becoming less numerous and the horny substance
more abundant, till, in the true horny sponges, such as the toilet-sponges, the

skeleton consists entirely

of horny fibres. The

ocellated Ghalina, fre-
quently cast ashore round

the British coasts, ex-
hibits an intermediate

condition between the

siliceous and horny forms.

By teasing out and ex-
amining a few fibres under

the microscope, a fine

core of siliceous spicules

will be seen in the axis of

each thread of spongin.
The illustration on

p. 528 represents a group

of sponges growing to-
gether. Near the base of

the black seaweed on the

stone there arises the

much -branched Desmaci-

dine sponge, so called

from its buckle - shaped

spicules; while from the

left branch of the former

grows a fiat alga encrusted

by another sponge of the

same order, and of a dull

yellow colour ; and at the

top of the colony is the

violet Spongelia. The

illustration to the left

represents another sponge

of this group (Axinella),

common in the Mediter-
ranean. In life this

sponge is of a yellowish
colour, and the oscules present a radiate
arrangement like the polyps of a branch of
fan-coral. The illustration on p. 543 illustrates
a sponge dredged by the Challenger, and known
as Esperiopsis challengeri, from six hundred
and thirty fathoms, east of the Celebes. The largest specimens are about 8 inches
in height. From a solid, strong stem six or seven stalks are given off at gradually

A SINGLE-RAYED SPONGE,

Axinella (nat. size).

SILICEOUS SPICULES OF MONAXONID SPONGES

(magnified 200-300 diameters).

TYPICAL GROUP.

543

increasing intervals from below upwards, and each bearing a hemispherical cup or
ladle, convex outwards. The in-current pores are on the concave, and the out-current
on the convex surface. To this order belongs the Neptune's cup sponge (Poterium),
attaining a height of 3 or 4 feet. It includes also the boring-sponges (Cliona), in
which the skeleton consists of scattered pin-shaped spicules. To compensate for
the inefficient support, the sponge excavates into limestone, chalk, or shells. Great
importance is attributed to the destructive power of
these sponges by Prof. Schmidt, who points out that
considerable portions of the coasts of the Mediter-
ranean consist of limestone, the disintegration of
which has been greatly hastened by the operation of
boring -sponges. In many parts the outlines of the
coast have consequently been much altered, and along
the Dalmatian shore, for a distance of a thousand
miles, one may find the beach thickly strewn with
stones completely riddled with the holes made by these
sponges, as shown in the illustration on p. 544. The
causes of this property of the burrowing-sponges are
not known; but there are two theories, mechanical
and chemical. According to the former, the sponge
bores by means of the grinding of its siliceous spicules
against the softer limestone. The action would be
assisted partly by the action of the contractile sub-
stance of the sponge-body, and partly by the currents
of water traversing the canals. On examining the
galleries of a shell or piece of limestone with a lens,
the surface is seen to be pitted with minute hemi-
spherical cavities, giving rise to a finely shagreened
appearance. The shagreen surface is characteristic
of the action of a burrowing -sponge, and serves to
distinguish the cavities and hollows due to the

sponge from those caused by worms, molluscs, or the action of water. Certain
minute five-sided plates were formerly supposed to assist in the excavating process,
but are now known to result from the breaking down of the organic layers of the
shell. On the other hand, the advocates of the chemical theory attribute the
excavating properties to the secretion of carbonic acid by the sponge, which is
thus enabled to dissolve the carbonate of lime of the shell or limestones ; but an
objection lies in the fact that carbonic acid is incapable of dissolving the organic
plates of shells. Recently it has been urged that the power of contractility
possessed by the sponge is a powerful aid in the work of excavation. Burrowing-
sponges are a trouble in oyster-culture, and it is suggested that at the time when
the free-swimming sponge-embryos are formed, a bank of old shells should be
placed between the oyster-beds and the tide. The bank would filter off the
embryos, which would grow in the old shells, and be subsequently destroyed by
immersion in fresh water. A figure of a fragment of limestone thus perforated by
sponges is given on the following page.

jEsperiopsis challengeri (£ uat. size).

544

SPONGES.

Fresh- Water To the group under consideration belong the fresh- water sponges

sponges. (Spongillidce), which live in ponds, canals, lakes, and rivers all over
the world ; and have been known to infest the pipes supplying a city with water.
The two commoner British species (Euspongilla lacustris and JEphydatiaflwviatilis)
grow on the piles of bridges, the sides of locks, the stems of water-weeds, or
form crusts on the bed of rivers. Euspongilla forms bright green crusts, from
the surface of which long, simple, or branched stems arise ; or the surface of the
crust may be simply conulated. This green colour is due to granular bodies which
crowd the cells near the surface of the sponge. Some naturalists consider these
bodies to be chlorophyll granules similar to those of plants ; others regard them as
single-celled algas. The chlorophyll, in the presence of sunlight and water, splits

LIMESTONE BORED BY SPONGE.

up the carbonic acid evolved by the sponge into carbon and oxygen, the latter
being used by the sponge for respiration. Fresh-water sponges growing in shady
places are of a pale grey or yellowish white colour; and when bright green
specimens are kept in the dark, they lose their green colour. The surface of
a fresh - water sponge is covered with fine pores, while here and there a few
large oscules are visible. From the pores fine in-current canals pass down to the
flagellated chambers, and from the latter proceed the rootlets of the out-current
canal-system. With a lens the spindle-shaped siliceous spicules of the skeleton can
be made out. They are about one-fiftieth of an inch in length and unite in bundles
which partly surround the canals, and are partly scattered irregularly in the ground
substance ; with the naked eye the bristling points can be seen projecting from
the surface. If a specimen be examined in autumn, there will generally be found
crowding the meshes at the base of the crust a number of small yellow spheres,
about one-twelfth of an inch in diameter, known as gemmules. They possess a firm
shell, with a small circular pore at one spot covered only by thin membrane. A
gemmule is a kind of internal bud, and is capable of developing into a new sponge.

TYPICAL GROUP.

545

When the season unfavourable to the life of the sponge arrives, a number of
wandering cells collect together into a mass which becomes coated with a horny
covering. Outside this a layer of siliceous spicules is secreted In Ephydatia
these spicules are, from their peculiar shape, termed
amphidiscs, two toothed discs being united by an axle,
the layer of amphidiscs being arranged with the axles
vertical to the surface of the gemmule. In the succeeding
spring the cellular mass in the interior bursts out
through the pore, and develops into a sponge. The
gemmule-spicules of Euspongilla are shaped like curved
needles pointed at each end, and with a granular surface.
Gemmules are formed, but apparently only rarely, in a
few marine sponges, such as Cliona and Chalina oculata.
These bodies are formed also by the fresh-water Bryozoa.
In addition to this asexual or vegetative formation of
gemmules, fresh-water sponges also form ova and sper-
matozoa. When the ova are fertilised they undergo
segmentation, and form oval ciliated embryos which are
about one-seventh of an inch in length, and are easily
to be seen swimming about in a glass vessel of water. They swim with the broad
end forwards ; the anterior upper half is dark and semitranslucent, the posterior
lower half glistening white and opaque.

EMBRYO OP A FRESH - WATER

sponge (magnified 100 diam-
eters).

Horny Sponges, — Order Ceratosa.

In this group, of which ordinary toilet-sponges furnish examples, the skeleton
is chiefly composed of fibres of a horny substance, termed spongin, and allied in
composition to silk. In the toilet-sponges the fibres of the skeleton form a close
felt-like network of soft elastic texture ; but some horny sponges are hard and
brittle, and others of the consistence of indiarubber. In most of the group
foreign particles, such as grains of sand, or siliceous spicules of other sponges, are
present in the fibres ; and in some the foreign bodies form a thick core covered with
a thin coating of spongin. Even in the softest toilet-sponges foreign particles are
included in the main fibres. The large purple fan-shaped lanthella from North
Australia belongs to this group; also Lufforia archeri (Neptune's trumpet)
from Yucatan, forming a magnificent cornucopia, five feet in length. Darwinella
possesses peculiar horny spicules.

Toilet- and The sponges commonly seen in shops may be arranged under

Bath-Sponges, three species, all of which occur both in the Mediterranean and
West Indies, namely, Euspongia officinalis, variety mollissima, the fine turkey-
or toilet-sponge ; E. zimocca, the hard flat disc-shaped sponge ; and Hippospongia
equina, the common bath-sponge or horse-sponge. Under these species are
included a large number of " varieties " and " grades," classified according to form,
quality of texture, colour, locality, etc. The sponge-merchant can define the exact
locality whence a specimen came, by observing the presence of characters which the
naturalist would not regard as specific. The merchant classifies his material into
vol. vi.— 35

546 SPONGES.

grades, and uses names expressing the locality, texture, etc. The softest and finest
is the Turkey cup-sponge, which usually forms deep or shallow cups. The whole
outer surface of the dense horny network is covered with minute holes, which
correspond to the groups of in-current pores ; in the cavity of the cup are a few
large holes about three-eighths of an inch in width, distributed irregularly or with
a tendency to a radiate arrangement. The large holes are the oscules or out-current
apertures. The second species is the zimocca, or hard-sponge, typically forming
rounded discs, convex below and flat at the top. The pores are arranged on the
outer side or margin, and a number of oscules cover the flat upper surface. The
texture is denser and less resilient than that of the toilet-sponge, which it some-
what closely resembles. The microscope shows the cause of the denseness to lie in
the thickness of the fibres composing the skeleton-network.

The common bath-sponge, or horse-sponge (Hippospongia), presents such wide
differences from the first two forms, that the naturalist places it in a different
genus. The holes on the surface of the loaf-shaped hemispherical mass do not
correspond to those in a toilet-sponge. The in-current and out-current orifices are in

SECTION OF COMMON BATH-SPONGE.

the walls of the wide canals which permeate the whole sponge-body, so that the
bath - sponge is really composed of much folded layers, or lamellae, with the
canal-system in the thin walls of the lamellae. The large holes on the surface
are " pseudoscules," and the tortuous passages into which they open are "vesti-
bules " to the true pores, which can be seen on the walls. The pores corresponding
with those on the outer surface of a toilet-sponge may be deep in the interior of
a bath - sponge. The elephant's ear-sponge from the Adriatic is a variety of
Euspongia officinalis. It forms a huge lappet, the edges of which may unite to
form a funnel-shaped cup two or three feet in height ; the pores are on the outer
side, and the oscules in groups on the inner. Cut up into flaps a few inches
square, these sponges are useful for house-cleaning, etc.

Many of the commoner kinds of sponges, termed hard-head, reef, etc., come
from the West Indies, and are included under E. zimocca. The bath-sponge
is less durable and more easily lacerated than the toilet-sponge, and has more
foreign particles in the fibres. In their natural condition toilet- and bath-sponges
look very different from the sponges in daily use. On seeing sponges in their
natural state, one wonders how it was discovered that they formed skeletons
possessing such useful qualities. A sponge living at the bottom of the sea appears

SPONGE-FISHING.

547

as a shining, blackish, fleshy lump, which cuts like raw meat, no trace of the
horny network being visible. The discovery would probably result from finding
cast up specimens with the skin and flesh partly rotted away from the more
durable skeleton. A toilet-sponge when alive is a blackish, cup-shaped fleshy
mass, with its surface covered with minute conical elevations. In the hollow of the
cup are the oscules, which appear smaller than in the skeleton, and are capable of
dilating and contracting. During life currents rush out of these holes. On the
outer surface of the sponge, by very careful inspection, sieve-like groups of pores
will be seen in the skin, between the conical elevations.

When a living sponge is torn or cut, a good deal of glutinous substance flows
away. The dark skin covers a light yellow fleshy substance, in which the canals
leading to the oscules are conspicuous. The walls of the canals are greyish, some
being filled with mud, others containing a marine-worm or crust-
acean, others, again, being empty. The skin-pores open into sub-
dermal spaces beneath, and from the floor of the latter canals
branch into the body-substance. The smallest canals finally
open into minute pyriform flagellated chambers ; and from each
of the latter there arises a rootlet of the out-current canal-
system. What is commonly known as the sponge forms a
supporting network of fibres in the gelatinous ground-substance,
the horny skeleton forming a kind of scaffolding. The fibres
are yellowish and translucent, and built up of concentric layers
surrounding a thin axial thread. Foreign particles, such as
sand-grains, flinty spicules of other sponges, etc., are included
in the main fibres. Each growing fibre is surrounded by
cylindrical cells which secrete it. When a fresh batch of
cells secretes a new layer, foreign particles on the surface of
the fibre become included within the new coating. The
embryos are minute oval bodies, which swim by means of
their cilia, and lead an independent life for a day or two.
They then settle down by becoming fixed at one end, and
develop into sponges.

. In addition to sexual reproduction, there is also vegetative
propagation. This characteristic has been made use of for cultivating sponges by
cuttings.

Sponge-Fishing.

Ascetta primordialis.
After Haeckel.

Sponges are found in depths ranging from two to one hundred fathoms, and
the methods of collecting depend both on depth and locality. Off" Dalmatia the
primitive method of harpooning is still employed. Two men go out in a small
boat ; one rows, the other leans over the edge holding a long fork. If the water
ripples, the rower throws in a half circle in front of him a few pebbles dipped in
oil. The Greeks employ a submarine spyglass, which simply consists of a pane
of glass let into the bottom of a tube or bucket. By this means they do away with
the effect of the surface ripples. In the Levant in depths of five to fifty fathoms
divers are employed, either naked or provided with a diving-dress. In the former

S48 SPONGES.

case, the diver, with a bag round his neck, takes hold of an oblong white stone,
with a cord attached ; he breathes vigorously for a few minutes, and plunges in
head foremost, holding the stone in front of him. He can only remain at the
bottom at the utmost for three minutes, during which time he hastily snatches
up the sponges, puts them into the bag, pulls the cord, and is drawn up. After
the first descent of the season he comes up with his nose bleeding. If this does
not take place it is considered a bad sign, and the diver will not consider himself
fit to continue the work. Divers with dresses can remain for an hour in depths
of from five to fifteen fathoms, but only for a few minutes in from twenty to fifty
fathoms. In depths over fifty fathoms a drag-net is used, either from a vessel or
hauled along from the shore. The net is fixed to a frame six yards in length and
one yard in height; this is composed of camel hair, and has four-inch meshes.
The sponges are taken ashore, pressed, squeezed, and rinsed, till the dark skin and
fleshy glutinous substance has been got rid of, or they are exposed for a short
time, and placed in a staked enclosure under water ; in a few days the soft animal
substance is trodden out, and the specimens are strung up to dry.

In a map of North America, the tongue-like peninsula of Florida will be seen
projecting between the Atlantic and the Gulf of Mexico. The tongue extends
beneath the sea as a submarine plateau, on which coral - reefs have formed,
parallel with the southern and western shores of the peninsula, but separated from
the mainland by shallow channels. From the point of the tongue extends a chain
of small islands, or "keys," formed from coral growth and its fragments. The
plateau forms a south-eastern expansion, the Great Bahama Bank, which sinks
along its eastern margin by a stupendous declivity of over ten thousand feet to
the great depths. The reefs on the plateau form rich sponge-beds, extending over
an area of several thousand square miles. Previous to 1840 the existence of these
valuable submarine beds was unknown. Now they afford a means of livelihood
to many thousands of men, and nearly a thousand vessels are employed in
collecting the crops.

The origin of the sponge-fisheries in the West Indian region was due to an
accident. Previous to 1840 all the sponges of commerce came from the Mediter-
ranean. In that year a member of a Paris firm of Mediterranean sponge merchants
was wrecked on one of the Bahamas, in the course of a passage from Jamaica to
Europe. He noticed that a great number of sponges were in use among the
inhabitants, and was told that they were obtained from the waters round the
island. On his return to Paris he arranged for consignments, and -thus the
Bahamas trade became established. In 1849 a cargo of sponges from Key West,
Florida, arrived in New York, and was about to be thrown away as unsaleable ;
the cargo was purchased, however, by a firm, which established a branch at the
new locality, and thereby founded the Florida trade.

When the inhabitants of the Bahamas and the Florida Keys found it would
pay to collect sponges, their spirit of enterprise was awakened, and putting off in
search, they continually found reefs overgrown with crops. Gradually the vessels
increased in number and tonnage, till the fleets amounted to seven or eight
hundred craft, mostly schooner - rigged, and of from five to twenty-five tons
burden. All over this region one method alone is in use, that of hooking the

SPONGE-FISHING. 549

sponges up with a three-pronged fork provided with a very long wooden handle.
Each boat carries a varying number of small dingheys. Two men are apportioned
to a dinghey, one for sculling, the other for hooking. The hooker leans over the
side, and views the surface of the reefs through a sponge-glass. Great skill is
required in sponge -fishing; indeed, the difficulty of hooking up a small dark
object in twenty or thirty feet of water, and often in a strong current, can be
imagined. Once a week the fleet returns to some selected locality to unload its
cargo into a crawl, — a staked enclosure covered with a few feet of water. The
preceding week's catch, with the skin and fleshy matter almost rotted off, is now
beaten, squeezed, hung in strings to dry in the sun, and finally packed in bales,
and sent to Nassau and Key West. Sponges used to be sold by weight, but owing
to the tendency to absorb moisture, and to the prevalence of the fraudulent
practice of weighting them with sand, they are now valued according to size,
shape, quality of fibre, etc. The fine toilet-sponge is found chiefly along the
eastern shores of the Mediterranean, from Trieste round by the Levant to Tripoli.
The distribution of the bath-sponge extends from East Greece, along the Levant
and the North African shore, and the zimocca-sponge from the Levant to Tripoli.
Good qualities of commercial sponges grow in the Red Sea; the Great Barrier
Reef off the north-east of Australia would probably yield a large supply. The
bulk of the harvest of sponges from Bahamas and Florida consists of common
bath-sponges.

R. KIRKPATRICK.

CHAPTER XVI.

The Lowest Animals, — Subkingdom PROTOZOA.

Characteristics,

The lowest animals belong to a world invisible to the naked eye,
a world whose very existence was unknown two hundred years ago,
despite the fact that its inhabitants abound on every side. In 1755 Rosel von
Rosenhof saw sticking on the side of a glass vessel of water and weed a tiny
particle of jelly, the movements of which attracted his attention. " It fastened
itself," he writes, "on the side of the glass; and since, like animals, it moves,
although very slowly, from place to place, and thereby continually alters its form,
and as I frequently examined the water with a magnifying-glass, the creature was
necessarily discovered ; as soon as I touched it, it contracted itself into a sphere and

PROTEUS ANIMALCULE.

The same animal in different shapes. (Magnified 600 diameters.)

fell to the bottom." Rosel removed the specimen to a watch-glass, and observed it
continually changing its shape. In consequence of this peculiarity, he named the
animal " the small Proteus " after the monster of fable. Later the animal was named
Amoeba, as the name Proteus had been bestowed on another animal. An amoeba is
composed of a small particle of living substance, called protoplasm, and resembles a
tiny blob of jelly, which continually but slowly changes its shape. The amoeba is

CHAR A CTERISTICS.

55*

generally found on the ooze of ponds, or the under surface of the leaves of aquatic
plants, but especially amongst conferva, in clear gently flowing water. When first
caught, the animal will appear as a tiny yellowish semitranslucent globular speck,
about one-hundredth of an inch in diameter; presently it becomes beaded with
rounded projections, some of which grow longer at the expense of others and of
the body, and may give off one or two branches. By the projection of these
processes, or pseudopods, the amoeba moves along in the direction of the longer
ones. " Sometimes," writes Leidy, " the animal creeps onward in a flowing manner
with comparatively simple cylindroid form, occasionally emitting a single pseudopod
on one side or the other. More commonly, in movement, it assumes a dendroid or
palmate form, or sometimes, diverging from the directly onward course, it becomes
more radiate in appearance. Not unfrequently it assumes more or less grotesque

proteus animalcule, (highly magnified).

shapes, in which almost every conceivable likeness may be imagined." The body,
of the amoeba is full of granules, which render it semiopaque, with the exception
of a thin clear outer hyaline zone, and near the centre is a globular or discoid body,
known as the nucleus, composed of a denser protoplasm than that which surrounds
it. Division of an amoeba into two is preceded by division of the nucleus. Near
the latter is a clear spherical space — the contractile vacuole — which gradually
expands, rather suddenly collapses, and reappears at the same spot, the systole and
diastole being slow and continuous. The contractile vacuole contains a clear liquid,
which is expelled on the collapse of the vacuole. This organ probably serves the
double function of respiration and excretion. The amoeba is omnivorous, but is
chiefly vegetarian, and browses on tender leaves, or feeds on diatoms and other
algae ; it surrounds the food-particle or organism with the protoplasm of its body
or of a pseudopod, and the ingested particle sinks in, surrounded by a zone of
water ; frequently there are several food-balls in the body of the animal. The

552 THE LOWEST ANIMALS.

food can be taken in, and the remains ejected at any point, but the latter frequently
appear to be cast out at one spot behind the nucleus and contractile vacuole.
The animal reproduces by dividing into two halves, each containing a portion of
the original nucleus and a contractile vacuole, and each growing to the size of the
original. A unit particle of protoplasm capable of carrying on the functions of
life, namely, nutrition and reproduction, is termed a " cell." Formerly, a unit of
this nature was supposed to be a sac or vesicle, hence the name " cell," which is
retained, though many cells are solid and without a definite wall. The Pro-
tozoans are animals consisting of a single cell, or colonies of cells. In the latter
case each cell is more or less independent of the others, and capable of carrying
on all the functions of life. All animals above the Protozoa are composed of
many cells united into a whole, in which there arises the principle of division of
labour.

The Protozoa are divided into two groups, the Rhizopoda and the Infusoria ;
in the former the body-substance is of more or less uniform consistence, and can
extend itself from any part of the surface in the form of pseudopods ; whereas, in
the latter, the outer layer is firmer and denser than the inner, and the animal has
a more or less definite shape. In place of pseudopods, the Infusoria develop on
their surface one or many fine processes in the shape of cilia or flagella, which
set up food-carrying currents, converging towards a definite mouth, and which
enable the animals to move rapidly about, when they are not fixed.

The Root-Footed Group, — Class Rhizopoda.

The simple organisms of this class take their name from their power of
protruding from the body the processes known as pseudopodia, which are often
branched like roots of a tree, and by means of which they creep about. The
group includes the amcebas, the foraminifers, the sun-animalcules, and radiolarians.
In the first the pseudopodia are simple and lobose ; in the second they are slender,
confluent, and reticulate; while in the two last they are simple, radiating, and
somewhat stiff.

The Amcebas, — Order Lobosa.

The chief character of this group consists in the usually broad lobose simple
form of the pseudopods, which flow out from the body in the shape of finger-like
processes. The simplest forms are apparently without even a nucleus, and on this
account have been separated from the rest as the Monera. As the first representa-
tive of the group, we may take the form known as Protomyxa, which forms
minute orange-coloured particles of jelly creeping over shells, and consists simply
of protoplasm containing granules, oil-globules, and food-particles. Occasionally a
specimen retracts all its pseudopodia, some of which are broad and others slender,
and becomes a quiescent sphere, the contents of which break up into numerous
portions, each of which forms a new individual. The amcebas are divided into
two groups, the shell-less (Nuda), and the shelled forms (Testacea). The common
amoeba, which has been described above, belongs to the former group, as also does
Pelomyxa, a large species found in the form of little white ovoid masses, about

RHIZOPODS.

553

the size of a pin's head, creeping on the mud of stagnant ponds ; in this animal
there is a definite fore-part and hind-part, the broader end of the ovoid mass
being in front. The figure represents the capsuled animalcule {Ar cello), common
in pools, especially where there is bog-moss. The brown horny shell is marked

orange-coloured protomyxa (magnified 140 diameters).

with a finely faceted pattern, and is shaped like a dome with a flat floor ; in the

centre of the floor is a circular hole, through which short lobose pseudopods emerge

from the body in the interior of the dome - like box. Arcella is capable of

secreting vesicles of air in its body-substance,

whereby it is enabled to rise. In Euglypha

the shell is sac-shaped, with a jagged free

margin, and the surface covered with regular

overlapping scales. In Difflugia the shell

is strengthened by the addition of foreign

particles. Amcebas are cosmopolitan;

occurring in sea and in fresh water, and a

few living in mosses or damp earth. Certain

forms of dysentery are said to be due to

amcebas, or at least to amceba-like phases

in the life -history of other Protozoa.

The fungus - animals (Mycetozoa), are
claimed both by botanists and zoologists.
The best known species is the flowers of tan, found in tan-yards, in the form of
large creeping masses of naked protoplasm, known as plasmodia. Cakes of proto-
plasm become segregated from the main mass, and break up into amoeba -like spores,
which again fuse to form plasmodia.

YOUNG CAPSULED ANIMALCULE, SEEN FROM ABOVE

(magnified), a, Fragment of Shell (magnified
600 diameters).

554

THE LOWEST ANIMALS.

Order Foraminifera.

If shelly sea-sand be looked over with a lens, there will often be seen tiny-
shells no bigger than the grains of sand amongst which they lie. The specimen
illustrated on p. 558, and whose shell is about one - twentieth of an inch in

diameter, was originally named the
spiral nautilus, with crenated joints.
Another kind (Miliolina) occurs in
the shape of porcelain-like oval shells,
one -twentieth of an inch in length,
with about five visible segments,
arranged somewhat like a string of
sausages wound round each other not
quite in the same plane. Foraminifera
are rhizopods whose simple sarcode-
bodies emit slender branching pseu-
dopods, and which form a shell of
membrane, of foreign particles of
sand, etc., of carbonate of lime, or, in
rare instances, of silica. The order is
divided into two groups, the Imper-
forata and the Perforata; in the former
of which the shell possesses only one
or a few comparatively large aper-
tures, whereas in the latter, in addition
to its main opening, the shell has its
walls perforated all over with small
pores through which pseudopods can
be emitted.

The Imperforata form shells of
membrane, agglutinated particles of
sand, mud, sponge-spicules, etc., or of
carbonate of lime ; the vast majority
of the Perforata form shells of the
last-named material. The imperforate
shells of carbonate of lime often resemble milk-white porcelain ; whereas the per-
forate shells, especially in early stages, have a glassy appearance.

Gromia is found both in fresh and brackish water and in the sea in
the form of minute, oval, egg-shaped bodies about one-twentieth of an inch
in length, fixed on tufts of corallines, or loose in the sand and mud. At first
there appears to be nothing remarkable about the tiny oval mass resembling
the egg of a zoophyte ; but presently from the opening at one end of the
membranous sac or shell granular threads of sarcode creep out and become
fixed on the glass slide ; slender trunks of sarcode extend themselves, and divide
into finer and finer branches, which reunite to form a network of streaming
granular filaments ever changing in form, and which may extend to six or eight

egg-shaped gromia, Gromia oviformis (magnified
600 diameters).

FORAMINIFERS.

555

times the length of the body. Every 'fibre exhibits an up and down stream of
granules suspended in clear hyaline sarcode. A diatom, infusorian, or other edible
prey, coming in contact with the pseudopods, is covered with a mass of protoplasm
formed by fusion of several filaments, drawn down to the mouth of the shell and
engulfed. Gromia moves by means of its pseudopods, which fix themselves and
draw the body along. When alarmed, the animal withdraws into its membranous
test.

The sandy Foraminifera, which are mostly deep-sea types, are composed of
masses of sarcode, sometimes of considerable size, which form shells or cases of
agglutinated mud, sand-particles, or sponge-spicules. They frequently attain a

a Hyperammina ramosa ; b and c, Astrorhiza limicola ; b, Entire ; c, Cut open.

large size ; for instance, Baihysiphon, from the Atlantic and also from fourteen
hundred and twenty -five fathoms off Amboyna, forms a slender annul ated tube, two
inches in length, and open at each end, the walls of the tube being composed of
cemented sponge-spicules. Haliphysema is found in shallow water in the North
Atlantic in the form of minute club-shaped bodies, one-twentieth of an inch in
height, with the narrowed lower end attached by a disc to zoophytes, etc., and with
the surface bristling with sponge-spicules. Hyperammina, generally distributed in
from sixty to three thousand fathoms, makes a test of cemented sand-grains and
sponge-spicules, at first forming a globular chamber with a long branched neck, the
branches of which again branch. Astrorhiza forms stellate single-chambered shells
of fine mud, slightly cemented, and lined inside by a smooth membrane ; at the
ends of the arms are large openings for the pseudopods ; the diameter of the disc
is about one-fifth of an inch, and that of the entire shell about half an inch ; the
animal lives in comparatively shallow water (about twenty fathoms), in the North
Atlantic. Certain other sandy species are characterised by the regular form of
their shells, which resemble those of calcareous species. The imperforate cal-
careous species are usually milk-white. The shell possesses only one or a few

556

THE LOWEST ANIMALS.

apertures. The seedlet miliolina, previously referred to, is one of the commonest
species ; it has a world-wide distribution from the shore to three thousand fathoms.
The terminal opening of the last and largest segment is guarded by a branched
0 tongue-like process. The Miliolite Limestone of the Paris
Basin is composed almost entirely of the shells of Miliolina
and other Foraminifera. A considerable part of Paris is
built of this stone, in which the tiny miliolinas can be
distinctly seen with the aid of a lens. The porcellaneous
Peneroplis forms a spiral, with a slit in the last-formed
segment, through which the protoplasm of the body can
be extruded.

Orbitolites, one of the Imperforata, forms discs from
one to two inches in diameter. The shell is composed
of a central coiled chamber, followed by concentric circles
of chambers, the pores for the emission of pseudopods
being situated on the edge of the disc. The different
species of Orbitolites form an interesting series, illustrat-
ing transitions from a simple to the most complex type. In a vertical section
of the disc of the figured species the innermost chambers exhibit the simple type,
later formed ones the intermediate, and the outermost series the highest type and
the greatest differentiation of structure.

Peneroplis pertusus. a, Lateral
view ; b, Front view. (Mag-
nified.)

Orbitolites. a, From above ; b, Transverse section (nat. size) ; c, Diagrammatic figure of section of Ch-bitolites
complanatus, illustrating the transition from the simplest to the most complex type of structure.

The shells of the perforate Foraminifera may be constructed of only one,
but most commonly of many, chambers, arranged according to various plans.
The simplest type with one chamber (Lagena) is shaped like a Florence oil-
flask ; in many -chambered forms the segments may succeed one another in a

FORAMINIFERS.

557

Polymorphina. a, b, c, From different aspects
(magnified).

straight line or in a spiral, and the coils of the spiral may or may not be in the
same plane; or, again, the segments may form alternately on each side of a
long axis.

In Polymorphina communis the segments are combined in a somewhat
obscurely spiral arrangement. In the Foraminifera group a number of forms
have arisen exhibiting an extensive series of
variations on a few simple types, and show-
ing transitions between forms which at
first seemed distinct. The majority of
species live at the bottom of the sea, but
some are pelagic, and occur in abundance on
the surface. Among the latter, Globiger-
ina is one of the most widely distributed.
Its shell is about one-fortieth of an inch in
diameter, and usually composed of seven globular chambers, arranged spirally in
such a manner that all are visible from above, but only the last four from below.
Each chamber opens by a crescentic orifice into the depression in the middle of the
lower surface. Perfect specimens bristle with long slender spines. The pores
afford passage to the pseudopods which stream along the spines. In life, the
shell is sunk in the midst of a bubbly sphere of protoplasm, which serves as
a float. The investigations of deep-sea expeditions have brought to light
the fact that the floor of the ocean, at depths between five hundred and

two thousand five hundred
fathoms over vast areas, be-
tween 110° north and south
of the Equator, is formed of a
pinkish white mud, containing
on an average about 60 per
cent, of carbonate of lime.
The presence of this material
is mainly due to shells of
Foraminifera, especially Glob-
igerinidce, and, to a small
extent, to the remains of
minute pelagic algse, known
as coccospheres and rhabdo-
spheres; the broken fragments
of the latter in the shape of
discs and rods being termed
coccoliths and rhabdoliths.
Over the greater part of the floor of the Atlantic, and over immense tracts in the
Western Indian Ocean and Pacific, over areas comprising in all about fifty millions
of square miles, the ocean-bed is formed of Globigerina ooze. Chalk is mainly
composed of the skeletons of Globigerinidai, coccoliths, etc., and, in fact, resembles
Globigerina ooze.

The question whether the Globigerinidce, which make up the bulk of the

shells of Globigerina (much magnified).

558

THE LOWEST ANIMALS.

ooze, live at the bottom as well as at the surface, has given rise to much discus-
sion. Dr. Murray has come to the conclusion that pelagic species do not live

near

Polystomella (magnified 200 diameters).

the ocean floor. His opinion is partly based on the fact that the area of Glob-
igerina ooze coincides with the area of surface temperature at which Globigerinas

SUN-ANIMALCULES. 559

are found to exist. When the surface water is too cold for surface Globigerinas,
no Globigerina ooze is found below. Numerous species of Foraminifera, which

live only at the bottom, and are never found
at the surface, contribute a small percentage
to the composition of the ooze, the bulk of
which is, however, formed of organisms which
have rained down from the surface. The
deposits occurring in depths over two thousand
five hundred fathoms do not contain calcareous
matter. The rain of Foraminifera skeletons
falls down from the surface as over the areas of
lesser depth, but the shells are dissolved before
they reach the bottom, apparently by the excess
of carbonic acid in the deep zones of the ocean.
Here the ooze is formed of red clay, — a material
barcode body op Polystometta after shell probably resulting from the disintegration of

HAS BEEN DISSOLVED IN ACID. a. Nucleus -, . . . , , . , . .

(200 diameters). volcanic remains, pumice, etc., and almost devoid

of organic traces. This deposit extends in its
more or less unmixed condition over an area of about fifty-two millions of square
miles, and is also present in varying proportions in Globigerina and other oozes.
In from three to four thousand fathoms in the Eastern Indian Ocean and in part
of the Central Pacific, over a total area of about two and a quarter millions
of square miles, the deposit contains a large percentage of siliceous skeletons of
Radiolaria, and is termed Radiolarian ooze. Beyond the northern and southern
boundaries of the Globigerina ooze, in the Arctic and Antarctic Oceans the deposit
consists of a fine, white, chalky -looking siliceous mud, with a green tinge in the
shallower depths, mainly composed of the frustules of Diatoms.

The figured Polystomella, which belongs to the Nummulite group (so named
because some of the species resemble coin -like discs), is cosmopolitan, ranging
from the shore-zone to abyssal depths. Only the last convolution of the spiral
series of chambers is visible, a section of the shell revealing one or two more
coils completely invested by the outer ; the radiating lines mark the divisions of
the chambers, and on the last partition of the last chamber is seen a series of
minute pores. The second figure shows the sarcode-body of a nearly related
species, whose shell has been dissolved by acid ; the nucleus (a) being visible in one
of the segments. Nummulitic limestones which cover an immense tract, extending
from the Pyrenees, along Southern Europe and North Africa, through Asia Minor
to the Himalaya, are composed of the shells of an allied genus (Nummulites).
As these rocks belong to the Tertiary epoch, and form some of the highest
Himalayan peaks, they indicate how recently these mountains have been elevated.

Sun- Animalcules, — Order Heliozoa.

These animalcules are inhabitants of fresh water; their chief character-
istic, and the one to which they owe their name, being the possession of long,
slender, somewhat stiff pseudopods, which radiate from all parts of the spherical

560

THE LOWEST ANIMALS.

body, like sun-rays, as represented in pictures. The common sun - animalcule
(Actinophrys) forms a tiny translucent spherical globule, bristling with
pseudopods, and about ^io of an inch in diameter. The pseudopods appear stiff
but are quite flexible, and the body contains several clear vesicles, one of
which is usually half emerged from the body and on the point of bursting ;
the nucleus being in the centre of the body. The animal can move over a
hard surface by the alternate relaxation and stiffening of its pseudopods,
and sometimes so quickly that it appears to run like a spider. When a
pseudopod touches some small organism, the latter seems to become paralysed,
the pseudopod approximating itself and its prey to the body, which sends up a

green sun-animalcule, Acanthocystis chcetophora (highly magnified).

lobe wherein the organism is enveloped. Reproduction commonly takes place by
simple division of the animal into two. The common sun - animalcule occurs
abundantly amongst the weeds in clear pond-water. The green sun - animalcule
(Acanthocystis) figured above is provided with a skeleton composed of fine
siliceous rods or rays, the inner ends of which, buried in the body, are tipped with
little discs, the outer ends being either simple or forked.

In another species the siliceous needles are arranged tangentially ; further,
the skeleton may be formed of a siliceous latticed sphere, as in the lattice-
animalcule (Clathrulina), which grows fixed to aquatic plants by the base of
its long flexible stalk. The body sends its long slender pseudopods through the
meshes of the lattice; the total length of the animal is about 20^ °f an mc^-

RADIOLARIANS.

56i

Sun-animalcules often form colonies which result from the buds or the products
of division remaining in contact and partly attached. The most likely places to
find sun-animalcules are pools in the
woods, where the bottom is covered
with dead leaves, and among aquatic
plants in ponds.

Order Radiolaria.

Both alive and in the form of
their skeletons many of the radiol-
arians are surpassingly beautiful.
Floating on the surface of the ocean,
their tiny spheres or pyramids of
translucent jelly glow with rich tints
of crimson, blue, or yellow. They are
all marine, and live in zones from the
surface to several thousand fathoms.
Many of the surface forms avoid a
strong light, and only appear after
sunset. Certain species which live in
depths below one hundred fathoms,
and whose bodies contain a dark
green or black pigment, are prob-
ably phosphorescent Radiolarians
are usually known by the flinty
skeletons formed by many of them;
yet it is not this feature which
separates them from the other orders
of rhizopods, but the possession of a
membranous central capsule in the
centre of the body and surrounding the
nucleus. The body - substance outside
the capsule is highly vacuolated in

many species, and especially in surface forms. A few are without a skeleton, and
consist of small spherical or oval masses of soft gluey protoplasm, with slender
radiating pseudopods, and one or several central capsules; the presence of more
than one of the latter indicating a colonial form of growth. In a few species
the skeleton is formed of a glassy - looking horny substance, termed acanthin,
arranged in the form of radiating spines.

The vast majority of species secrete a siliceous skeleton which assumes an
endless variety of forms, such as trellis-work spheres, concentric spheres or boxes
joined by radiating spines, helmets, baskets, lanterns, bee-hives, discs, rings, etc.
Haeckel has described over four thousand species, and possibly as many more could
be added to this number. Radiolaria are divided into two groups ; in the first of
these there is either no skeleton or one of silex, while in the second the skeleton

vol. vi. — 36

lattice-animalcule, Clathrulina (magnified
350 diameters).

562. THE LOWEST ANIMALS.

is formed of radiating spines of a horny nature. The first group is subdivided into
three sections, according to the characters of the central capsule. In the first
section the capsule is spherical and uniformly perforated by numerous small pores ;
in the second conical, with a perforated sieve-like floor area below ; and in the
third it has one main aperture and one or a few accessory ones, and is surrounded
by a dark pigment. In the forms with a siliceous skeleton the geometrical
pattern of the skeleton conforms more or less to the shape of the central capsule,
being either spherical or conical. The central capsule is regarded as being
homologous with the calcareous shell of Globigerina. Reproduction takes place by
simple division into two, or by the breaking up of the body-substance into oval
spores, each provided with a flagellum or whip. Two spores, which may be of
similar or of different size, fuse together ; the resulting individual growing into
an adult radiolarian. Certain yellow corpuscles present in the outer part of the
body of surface radiolarians are unicellular parasitic algse, which can be separated
and cultivated independently of their host. The radiolarians live floating at
all depths. Some forms are abyssal, living in depths of one thousand to two
thousand five hundred fathoms. Over certain areas in the Central Pacific and the
south-eastern part of the Indian Ocean the ooze forming the ocean-bed is chiefly
made up of their skeletons, sometimes to an extent of eighty per cent, of the deposit,
which has hence been termed radiolarian ooze. The chalky-looking rock, known
as Barbados earth, a Tertiary formation, is composed almost entirely of skeletons
of radiolarians. Somewhat similar deposits exist in the Nicobar Islands, in
Greece, and in Sicily. Fig. 1 of the Plate shows the elegant lattice sphere of
Rhizosphcera. Fig. 2 represents Sphcerozoum, whose skeleton consists of loose
spicules, arranged tangentially. ActinomTna (Fig. 3) possesses three concentric
lattice-spheres, joined by radiating spikes. Fig. 7 represents a deep-sea form
(Challengeria), whose oval case is formed of a regular, very fine-meshed network.
Fig. 8 depicts the elegant lattice-sphere of Heliosphcera ; while Lithomespilus,
Ommatocampe, and Carpocanium are shown in Figs 4, 5, and 6, and Clathrocyclas
and Dictyophimus in Figs. 9 and 10.

The Infusorial Animalcules, — Class Infusoria.

The name Infusoria, which came into use a hundred years ago, was applied
to certain tiny living specks which appeared in infusions of hay, etc. The animal-
cules so named were classed with the worms and radiated animals, or zoophytes.
As the microscope improved, infusorians were found to possess a considerable
amount of structure. Ehrenberg attributed to them a highly complex organisa-
tion, supposing them to possess intestines, nervous system, etc. Later observations
negatived these views, and showed them to be animals formed of one cell or
composed of a colony of one-celled individuals. It is true that this cell, or unit-
mass of protoplasm, may show a wonderful amount of differentiation, what with its
nucleus, contractile vacuole, mouth and gullet, its variously arranged cilia or flagella,
its contractile fibres, its separation into an outer denser and an inner more fluid
protoplasm, and its horny cups, stalks, etc. Most of the species here described live
in ponds and ditches, the larger forms preferring clear to stagnant and muddy water.

RADIOLARIANS.

INFUSORIANS.

5<53

mail-coated flagellata (highly magnified).

Flagellated Infusorians,— Order Flagellata.

The characteristic of the group is the possession of one or two flagella, or small
whip-like appendages, at the base of which is an opening in the denser surface-
layer of protoplasm ; a nucleus and contractile vacuoles are present, and frequently
a brilliant red spot of pigment, known as the eye-spot. The Monads, which are
the simplest members of the group, are
common in fresh water and in infusions ;
typical forms consisting of a spherical
or oval cell provided with a flagellum.
Some species contain chlorophyll, and are
claimed by the botanists. The common
Volvox, for instance, which forms a green-
coloured, spherical colony of monad cells
has been described as a plant and also as
an animal by botanists and zoologists
respectively. The animal and vegetable
kingdoms converge downwards towards a

common point, at which it is difficult to say whether the manifestations of the
physical basis of life — i.e. protoplasm — are such as we ascribe to plant life or to
animal life. In the case of Volvox, the presence of chlorophyll would at first sight
seem to stamp the organism as a plant ; but the phases of life-history are rather
those of an animal organism. The collared group possess cup-like collars, and
they frequently secrete horny receptacles or cups, which may form elegant tree-
like colonies.

The mail-coated group are of very varied form, the body being often pro-
longed into long spiny processes. From the presence of cellulose in the cell-wall,
and of chlorophyll in the body-substance, the proper position for these organisms
would appear to be the vegetable kingdom, but taking their general life-history
into consideration they may be regarded as animal organisms. They possess two
large flagella which fit into grooves. Ceratium tripos (often looked upon as

an alga), which sometimes forms chains of twenty or
more individuals, is phosphorescent.

On calm dark nights during the summer and autumn
the surface of the sea is occasionally seen to be per-
vaded by a beautiful bluish or greenish luminosity.
The appearance of the phosphorescence is somewhat
capricious, but it will best be seen on calm warm
nights when there has been a gentle sea - breeze for
several days. This strange phenomenon has attracted
attention from the earliest times, but it was not till
the middle of the last century that the cause was dis-
covered. The luminosity is in most cases due to the presence of multitudes
of tiny jelly-spheres, each smaller than a pin's head. On taking up a tumbler
of the sea water, the spheres frequently form a thick layer at the surface. By
separating a few of the organisms on blotting - paper, the light emitted will

PHOSPHORESCENT ANIMALCULE,

Noctiluca (magnified 150
diameters).

564

THE LO WEST ANIMALS.

Pyrocystis (magnified 100 diameters).

enable one to see the time by a watch, at a distance of a foot or more. A few

organisms swimming or floating about in plenty of sea-room in a tumbler of water,

will not become luminous unless the water be
shaken about, but when crowded together, they
become diffusely luminous, owing to mutual
jostling and irritation. The luminosity in an
individual sphere, which should be inspected with
a lens, may appear as a sudden, generally diffused
flash, followed by darkness or by less intense
light, or again, in the form of brilliant points of
light. The name of the organism, which belongs
to the flagellated infusorians, is Noctiluca. The
body forms a peach-shaped cyst, about one-fiftieth
of an inch in diameter, and with a tough mem-
branous wall. A groove on the surface sinks at
one end into a funnel leading into the interior.

From the interior of the funnel there arises a large transversely striated flagellum,

or proboscis, by means of which the animal swims, and there is also in the

same place a fine whip-like flagellum. At the apex of

the funnel there is a mass of sarcode, which extends

itself as a wide-meshed, highly-vacuolated network, to

the inner wall of the cyst, where it forms a thin layer,

whence the phosphorescence emanates. Noctiluca

multiplies by dividing into two, or by becoming

encysted, after drawing in its flagella, and breaking

up into numerous ciliated helmet-shaped "swarm-
spores." Frequently two organisms fuse into one which

may then divide up into spores. Noctiluca is found

only in waters near land, the related forms met with

in the open ocean belonging to the genus Pyrocystis.

In one of the species of the latter the body is spherical,

about one-thirtieth of an inch in diameter, and without

the big flagellum. The phosphorescence, which in each

individual chiefly emanates from the nucleus, is dis-
played on the ocean surface on calm nights in the

Tropics. Prof. Butschli regards this species as an

encysted or resting phase of the common form-

Noctiluca occasionally swarms in such abundance as to

give in daytime a reddish or yellowish hue to the

surface. When the sea is rough, the organisms are

dashed below the surface, and do not form a sufficiently

continuous layer to give rise to much luminosity, and

when the wind is off shore they are blown out to sea.

Among the Flagellata are included certain parasitic organisms, which, owing

to their being immersed in nutrient fluids, are not compelled to seek further for

food, and do not possess flagella. The Gregarina, living in the intestine of the

mussel-animalcule (Stylonychia

mytilus) under surface.
a, Mouth ; b, Contractile vacuole ;

c, Nucleus. (Magnified 150

diameters.)

JNFUSORIANS.

565

lobster, is an elongated worm-like organism about two-thirds of an inch in length ; it

multiplies by becoming a spherical cyst, the contents of which break up into minute

spore-like bodies with spindle-shaped cases,

which are set free on the bursting of the

cyst. Each of the spore -bodies also

ruptures and liberates an amoeba - like

organism, which ultimately develops into

an adult gregarina. Another species of

gregarina lives in the intestines of the

earth-worm. The Sporozoa are oval or

spherical monad - like bodies, but without

flagella, and live as parasites in the cells

of plants and animals. Cancer and certain

forms of malaria have been attributed to

the presence of organisms of this nature in

the fluids and tissues of the body.

Ciliated Infusoria, — Order Ciliata.

The organisms of this
group are provided with
cilia, limited either to the
under side of the body, or
forming a circle or spiral
at one end, or arranged
uniformly over the sur-
face. Cilia are slender
hair-like processes of the
body, which move by
bending and straighten-
ing themselves in unison ;
flagella are larger whip-
like organs, and act more
independently, the range
of motion is not so re-
stricted, and there are usually only one or two present on a
celL A few typical and common species are described.

The mussel-animalcule (Stylonychia), common in stagnant
water, has the flattened oval body one-hundredth of an inch in
length ; on the under side is a ring of cilia, and at one end a
funnel-shaped depression or mouth (a) with ciliated margin,
leading through the dense outer protoplasm into the more
fluid inner mass. The two dark oval bodies (c) are nuclei,
and the clear spot (b) is the contractile vacuole which contracts
rhythmically once in about every ten seconds. The creature can stalk along on
the large bristle-like processes, in addition to swimming by means of its cilia ; the

BELL-ANIMALCULE ( Vorticdld).

a, Slightly magnified ; b, Magnified 600 diameters
n, Nucleus ; m. Muscle-band.

NODDING BELL-ANIMAL-
CULE, Epistylis
(nat. size = ^\^
inch).

566

THE LO WEST ANIMALS.

rosei/s trumpet-animalcule, Stentor (magnified 200 diameters).

oral cilia set up currents which
converge to the mouth -funnel,
and carry in other infusoria,
diatoms, etc.

The bell-animalcules usually
possess stalks, and are either
solitary or form branching colo-
nies. Vorticella, whose outline
is like that of a wine-glass, is
provided at the rim with an
incomplete circlet of cilia, one
end of which passes down into
the mouth-funnel at the margin
(r) of the disc; the stalk con-
tains a contractile band (m)
which produces a rapid jerking
motion by throwing the stem
into coils; in the body-mass lie
the nucleus {n) and contractile
vacuole (v). Reproduction takes
place by transverse division into
two. Ehrenberg observed twelve
individuals to originate from one
within twenty -four hours, so
that, calculating on this basis,
one million individuals would be
produced within twenty days.
The common-branched bell-ani-
malcule (Carchesium) divides
more rapidly, namely, once in an
hour; each again being soon
ready for division, so that one
thousand could arise in ten hours,
and a million in twenty hours ;
but, as a matter of fact, only
two hundred have actually been
observed to have been formed in
one day, owing to the intervals
between successive divisions be-
coming longer. The vigour of
the exhausted stock becomes
rejuvenated, however, by the
fusion or conjugation of two
individuals into one.

The nodding bell-animalcule
(Epistylis) forms little branching

JNFUSORIANS.

567

colonies growing on Conferva in stagnant water. When the animal is disturbed, the
heads droop down towards the stalks. One of the forms most frequently met with
is Carchesium, whose tiny branched tree-like colonies resemble moulds ; but a few
moments' inspection will undeceive the observer, for the little white globular stalked
heads will be seen to be drawn down towards the base of the colony with a rapid
jerking movement.

The trumpet-animalcule (Stentpr) is of comparatively large size, being about
one-twenty-lifth of an inch in length when extended. It is usually to be found
fixed by its pointed end on
the under side of duckweed
Its form continually alters
from a small knob wheni
contracted, to a trumpet -
shaped body when extended ;
and when in motion its shape
continually changes, being in
turn ovoid, pyriform, or even
spherical. The surface is
corrugated and covered with
rows of cilia, by means of
which the animal swims
about. The long cilia at
the upper part form a spiral,
within the upper margin of
which lies the mouth -slit.
The mouth opens into a
funnel, leading into the sar-
code of the interior. The
contractile vacuole lies to
the right of the mouth-slit,
and the nucleus forms an
elongated beaded band along
the length of the body. The
ridge of cilia passing down
vertically is the mouth-
fringe of a new animalcule
about to be formed by division. A cleft sinks in obliquely at one side of the ridge
which assumes a wavy outline and later a spiral ; the cleft sinks, till two complete
animalcules are formed, with one-half of the nucleus, and a contractile vacuole in
each. New individuals may also arise by the budding off of tiny ciliated embryos
from the nucleus. The species of trumpet-animalcule most commonly met with is
of a brilliant green colour; frequently clusters of them are found clinging by their
pointed ends to the stem of a water-weed. A specimen has been cut into three
parts, care being taken to leave a fragment of nucleus in each, with the result
that each part has repaired itself into a complete animal; the central part, for
instance, developing a head and a tail-end.

marine animalcule, Acineta (magnified 600 diameters).

568

THE LOWEST ANIMALS.

The spiral-mouthed animalcules {Spirostomum) are among the largest of the
class, and visible to the naked eye, especially in sunlight, as slender golden threads
about one-tenth of an inch in length. The body is cylindrical, and the surface

covered with rows of cilia ; the mouth-
slit extends along half the length of the
\\ I * I J under side, and is bordered on its left

side by a fringe of long cilia. The
animalcule is frequently twisted on its
long axis, the mouth-cilia forming a
spiral ; multiplication takes place by
transverse fission through the middle.

The curious marine animalcule
Acineta is probably related to the
ciliated infusorians. The stalked club-
shaped body is usually fixed on sea-
weeds or Bryozoa. From the upper end
a number of straight sucker -like ten-
tacles proceed ; a nucleus and also clear
vesicles are present in the body-
substance ; and the embryos are ciliated.
The bud -bearing Hemiophrya is
also a marine-animalcule ; it possesses a
few suckers and a larger number of
longer prehensile tentacles; on its margin
several buds are formed, each contain-
ing a process of the nucleus, and the
young forms when liberated are ciliated
on their lower surface. The long tentacles capture and disable the prey, and
bring it within reach of the suckers, which then surround and dissolve it, and
finally appear to pump the newly-acquired nutriment into the general body-
substance.

R. KIRKPATEICK.

BUD-BEARING ANIMALCULE, Hemiophrya

(highly magnified).

spiral-mouthed animalcule, Spirostomum. a, Nat. size.

INDEX.

VOL. VI.

Abraxas, 116.
Acanthechinus, 277.
Acanthiidae, 190.
Acanthocephali, 448.
Acanthocercus, 284.
Acanthocinus, 154.
Acanthocystis, 560.
Acanthodoris, 354, 355.
Acanthosoma, 188.
Acari, 241.
Acarina, 242.
^ccra, 362.
Achmta, 444.
Achatina, 348.
Achatinellidm, 348.
Acherontia, 96.
Acineta, 568.
Acmsea, 397.
Acmmidas, 397.
Acridiidse, 179.
Acrocinus, 154.
Adam, 256.
Actaeon, 361.
Actinia, 500, 501.
Actinocrinus, 301.
Actinometra, 300.
Actinomma, 562.
Actinophrys, 560.
Admete, 372.
^■Bgirus, 355.
^Eolidia, 356, 358.
sEolidiidw, 358.
u&ptasia, 500.
^Squipalpa, 162.
jEschnidas, 168.
sEtJieria, 410.
jEtheriidse, 410.
Agalena, 229.
Agalcnidse, 229.
Agaristidaz, 111.
Agate-Snail, 348.
Agassizocrinus, 299
Agclecrinus, 295.
Agrionidaz, 169.
Agriotes, 144.
Albertia, 446.
Akyonium, 512.
Alder-Flies, 163.
^^es, 207.
Allurus, 439.
Allolobophora, 439.
Alpheidee, 270.
Amalthca, 390.
Amaurobiidw, 230.
Amaurobius, 230.

Amber-Snails, 348.
Amblypygi, 219.
Amoeba, 552.
Ammonites, 340.
Ammonoidea, 340.
Amphiora, 308.
Amphibola, 352.
Amphibolidae, 364.
Amphicora, 438.
Amphineura, 398.
Amphipoda, 277.
Amphithoe, 278.
Amphitretus, 331.
Ampullaria, 389.
Ampullariidae, 389.
Anatina, 418.
Anartiostigma, 205.
Anatinacea, 417.
Ancilla, 373.
Ancistroteuthis, 337.
Ancula, 355.
Aneylus, 350.
Andania, 277.
Andrena, 42.
Andrenidse, 42.
Anemonia, 500.
Anguillula, 449.
Animalcules, 553.
Annelida, 432.
Anobium, 146.
Anodonta, 411.
Anomia, 404.
Anomiidae, 404.
Anomura, 261.
Anoplodium, 470.
Antedon, 299, 301.
Antheraea, 93.
Anthobranchiata, 354.
Anthocotyle, 466.
Anthomyinse, 71.
Anthonomus, 150.
Anthophora, 44.
Anthozoa, 495.
Anthrax, 60.
Anthrenus, 140.
Anthribidae, 152.
Antipatharia, 510.
Antipathes, 510.
Ant- Lions, 165.
Ants, 27.
Apatura, 87.
Aphaniptera, 75.
Aphidae, 196.
v^is, 196.
Aphodius, 142.

Aphrodite, 433.
Aphrophora, 195.
Apidae, 45.
Apiocrinus, 298.
Apion, 149.
^is, 45.
Aplacophora, 399.
Aplysia, 363.
Aplysiidm, 363.
Apoderus, 150.
Apodidse-, 285.
Aporia, 92.
Aporrhaiidm, 385.
Aporrhais, 385.
^?ws, 285.
Arachnida, 204, 213.
Arachnocystis, 297.
Aradus, 190.
Aranese, 220.
Araschnia, 86.
Arbelidae, 103.
^4rca, 405.
Arcella, 553.
Architeuthis, 334.
Arcidas, 404.
Arctia, 111.
Arctiidm, 111.
Arcturidee, 273.
Arenia, 436.
Arenicola, 435.
Argiopidae, 231.
Argonauta, 331.
Argulus, 283.
Argynnis, 84.
Argyroneta, 229.
Argyronetidae,, 229.
Arion, 345.
Arionidae, 345.
Aristocystis, 296.
Ark-Shells, 404.
Armadillidium, 276.
Aromia, 153.
Army- Worm, 55.
Arrow- Worms, 456.
Artemia, 286.
Arthrolycosa, 221.
Arthropoda, 3.
Artiostigma, 205.
Aryas, 244.
Ascaris, 452.
Ascetta, 546.
Asettota, 275.
Asellus, 275.
Asilidse, 59.
Asilus, 60.

57°

INDEX,

Asopia, 118.
Asparagus-Fly, 71.
Aspergillum, 418.
Aspidogaster, 466.
Astacidea. 263.
Astacopsidm, 268.
Astacus, 264.
Asterias, 305.
Asterina, 305.
Asteroidea, 304.
Asthenosoma, 311.
Astrma, 509.
Astroides, 508.
Astropecten, 305.
Astropyga, 311.
Astrorhiza, 555.
^ter, 243.
Atelecrinus, 300.
Atemeles, 135.
Athalia, 17.
Atlanta, 394.
Atlantidse, 394.
Atractonema, 451.
Attagenus, 140.
Attelabus, 150.
Attidm, 234.
-4tt«s, 235.
^%a, 269.
Atypidm, 226.
Atypus, 226.
Auger-Shells, 371.
Aulostoma, 443.
Aurelia, 492.
Auricula, 349.
Auriculidm, 349.
Auronectidse, 483.
Avicula, 407.
Avicularia, 224.
Aviculidae,, 407.
Axinella, 542.

Baculites, 340.
Balanidaz, 281.
Balaninus, 150.
Balantium, 368.
Balanus, 281.
Balatro, 446.
Baridius, 151.
Barnacles, 280.
Basommalophora, 349.
Bassus, 23.
Bath-Sponge, 545.
Bathycrinus, 302.
Bathydoris, 355.
Bathysiphon, 555.
Batrachomyia, 74.
Bdelloidea, 446.
Beak-Shells, 385.
Bee-Flies, 60.
Beche-de-Mer, 314.
Bees, 36, 42, 45.
Beetles, 123.
.SeZa., 372.
Belemnitidw, 338.
Bell- Animalcules, 566.
Bellinurus, 251.
Belonogaster, 42.
Belostoma, 193.
Bembecidse, 33.
Bembex, 33.
Beroe, 476.
Beroidse, 476.

j?iWo, 58.

Bibionidm, 58.
Bioriza, 21.
Bipalium, 471.
Bird-Lice, 176.
Birgus, 262.
Biston, 114.
Bivalves, 401.
Bladder-Worm, 463.
Blattidse, 184.
^a^s, 147.
Blastoidea, 303.
Blow-Fly, 64.
Blue Butterflies, 88.
Boletophila, 56.
Bombardier Beetle, 131.
Bombus, 46.
Bombycidie, 95.
Bombyliidw, 60.
Bomhyx, 95.
Bonellia, 444, 445.
Book-Lice, 175.
Book-Scorpion, 237.
Boring Sponges, 543.
Bot-Flies, 72.
Bothriocephahis, 463.
Bothriuridss, 215.
.5<%s, 118.
Bougainvillca, 487.
Bourgeticrinus, 299.
Bracliinus, 131.
Brachionus, 446.
Brachiopoda, 427.
Brachyelytra, 134.
Brachyura, 255.
Braconidee, 21, 26.
Brain-Corals, 510.
Branchipodidee, 286.
Branchipus, 286.
Braula, 75.
Braulidse, 75.
Brechites, 418.
Breeze-Flies, 58.
Brenthidas, 152.
Brisingidae, 306.
Brissopsis, 309.
Bristle-Tails, 203.
Bristle-Worms, 432.
Brittle-Stars, 306.
Bromius, 157.
Brotolomia, 113.
Bruchidse, 154.
Bruchus, 155.
Bryozoa, 419.
Bubble-Shells, 362.
Buccinidee, 376.
Buccinum, 376.
Buff-Tip, 99.
Bugs, 188.
Buliminus, 347.
Bulimulus, 347.
Bulimus, 347.
.#«««, 362.
Bullidaz, 362.
Bupalus, 115.
Buprestidee, 143.
Burnets, 102.
Burnished Wasps, 26.
Burying Beetles, 137.
Buthidaz, 215.
Buthus, 216.
Butterflies, 77, 83.

Byturidx, 139.
Byturus, 139.

Caddis-Flies, 159.
Calamary, 334.
Calappidse, 259.
Calcareous Sponges, 535.
Calcaria, 534.
Caligus, 283.
Callichromides, 153.
Callidinia, 446.
Callidium, 154.
Callidulidaz, 104.
Calliphora, 64, 67.
Calocoris, 190.
Calosoma, 132.
Calpicrmis, 384.
Calycozoa, 495.
Calyptrwa, 390.
Calyptrmidm, 390.
Cambalidie, 211.
Camberwell Beauty 86.
Campodea, 203.
Camponotus, 31.
Camptosomata, 156.
Cancellaria, 372.
Cancellariidw, 372.
Cancer, 255.
Cancridm, 255.
Caponiidse, 228.
Caprella, 278.
Caprellidse, 278.
Caprellina, 278.
Capulus, 390.
Carabidm, 130.
Carabus, 131.
Carcinus, 255.
Carchesium, 566.
Cardiacea, 414.
Cardiapoda, 394.
Cardiidse, 414.
Cardiliidm, 413.
Cardioceras, 340.
Cardissa, 414.
Garditidse, 410.
Cardium, 414.
Caridea, 268.
Caridina, 269.
Carinaria, 394.
Carnosa, 541.
Carpenter-Bees . 43.
Carrier-Shells, 390.
Carteria, 200.
Carychium, 349.
Caryocrinus, 296.
Case- Weavers, 102.
Cassida, 157.
Cassididss, 381.
Cam's, 382.
Cataulus, 390.
Catocala, 112.
Catometopa, 257.
Catoxantha, 143.
Caulastraza, 499.
Cavolinia, 368.
Cavoliniidm, 367.
Cecidomyia, 56.
Cecidomyidm, 56.
Ccnobita, 261.
Centipedes, 204.
Centrotus, 195.
Cephalopoda, 328.

INDEX.

57i

Cephidm, 15.
Cephus, 15.
Ceratium, 563.
Ceratosa, 545.
Ccrambycidm, 152.
Ceratites, 340.
Ceratorrhhia, 143.
Cercaria' 468.
Cerceris, 36.
Cercopidee, 195.
Cereactis, 500.
Cerianthus, 500.
Cerithidea, 385.
Cerithiidm, 385.
Cerithium, 385.
Cermatobiidse, 205.
Cermatobius, 205.
Ceroplatus, 56.
Cerura, 100.
Cestoda, 459.
Ces<%s, 476.
Ccthosia, 84.
Cetochilus, 283.
Ccidhorrhynchus, 151.
Chserocampa, 98.
Chsetifera, 445.
Chsetoderma, 400.
Chmtodermatidm, 400.
Chmtognaiha, 456.
Chsetopteridae, 436.
Chaetopterus, 436.
Chalcididae, 22.
Cholcophora, 143.
Chalicodoma, 42.
Chalina, 542.
Challengeria, 562.
Chama, 415.
Chamidse, 415.
Char seas, 114.
Chank-Shells, 375.
Cheese- Hopper, 72.
Cheimatobia, 115.
Chelifer, 237.
Chclifcra, 276.
Cheliferidae, 238.
Chermes, 198.
Cherry-Fly. 71.
Chicoreus, 379.
Chigoe, 76.
Chiliiia, 352.
Chilinidee, 350.
Chilognatha, 209.
Chilopoda, 204.
Chilostomata, 422.
Chiridium, 237.
Chiridota, 312.
Chironomidae, 52.
Chironomus, 52.
Chiroteulhida}, 337.
Chirotcuthis, 337.
CMore, 399.
Chitonidae, 398.
Chithonius, 238.
Chlamydoconcha, 410.
Chlamydoconchidae, 410.
Chlorops, 72.
Choanopoma, 390.
Chondrilla, 541.
Chondropoma, 389.
Chondrosia, 541.
Choristida, 540.
Chrysaora, 492.

Chrysididm, 26.
Chrysis, 27.
Chrysodomus, 376.
Chrysogorgmiiidm, 516.
ChrysomcMdae, 155.
Chrysopidae, 166.
Chrysops, 166.
Cicada, 194.
Cicadidie, 193.
Cicindela, 130.
Cicindelidm, 130.
Cigara, 297.
Ciliata, 565.
Cife, 104.
Cimex, 190.
CzYce, 414.

Circular-Seamed Flies, 61.
Cirripedia, 280.
Cirroteuthis, 331.
Cistula, 390.
Citigradse, 232.
Cixius, 195.
Cladactis, 500.
Cladocera, 284.
Cladocora, 508.
Cladodactyla, 319.
Cladonema, 484.
Cladophiurae, 306, 307.
Clams, 413, 414.
Clathrulina, 560.
Clathurella, 372.
Glausilia, 473.
Clavatella, 484.
Clavatula, 372.
Clavicornia, 135.
Claviger, 136.
Clear- Wings, 100.
Clegg, 59.
Clepsine, 444.
Clepsinidse, 443.
Cleridse,, 145.
Clerus, 146.
Click-Beetles, 143.
CWo, 368.
Cliona, 543.
Ctarae, 366.
Clisiocampa, 107.
Clithon, 395.
Clothes-Moths, 120.
Clubionidas, 228.
Clymenidm, 436.
Clytides, 153.
Cnidaria, 478.
Coccidee, 198.
Coccinella, 158.
Coccinellidse, 158.
Coccoliths, 557.
Coccus, 200.
Cochineal Insect, 200.
Cockchafer, 142.
Cockles, 414.
Cockroaches, 184.
Cocoa-Nut Crab, 265.
Ccelenterata, 474.
CoeTwnympha, 88.
Coleophora, 102, 122.
Coleoptera, 123.
Colly ris, 130.
Colhjrodes, 130.
Colorado Beetle, 157.
Colossendeis, 249.
Columbarium, 372.

Columlmtsch Fly, 58.
Columbclla, 378.
Columbcllidsc, 378.
Comma Butterfly, 86.
Gominclla, 377.
Cones, 370.
Concholcpas, 380
Conides, 370.
Compidw, 63.
Conops, 63.
CwMts, 371.
Convoluta, 470.
Copepoda, 283.
Copper-Butterflies, 88.
Coral- Islands, 517.
Coral-Reefs, 517.
Coraliophila, 380.
Coralliophilidse, 380.
Corallium, 516.
Corals, 474, 495.
Corbicula, 414.
Cordilophora, 491.
Coreidee, 188.
Corixa, 193.
Corn-Moth, 120.
Coronula, 282.
Corotoca, 135.
Corymorpha, 486.
Cosmetidsc, 240.
Cosmia, 112.
Cossidae, 103.
Cossus, 103.
Cowries, 383.
Crabronidee, 35.
Crabs, 253.
Crambractinidse, 501.
Crambractis, 501.
Crangon, 269.
Crangonidse, 268.
Crania, 431.
Craniidm, 431.
Craw-Fish, 263.
Cray-Fish, 264.
Crenatula, 408.
Crepidula, 390.
Cresm, 368.
Cribrella, 306.
Crickets, 176.
Crinoidea, 297.
Cristatella, 422.
Crossocerus, 35.
Crotalocrinus, 301.
Crucibulum, 390.
Crustacea, 248, 253.
Cryptochiton, 398.
Cryptodesmidse, 212.
Cryptopidee, 206.
Cryptoplax, 398.
Cryptops, 207.
Cryptosomata, 157.
Cryptus, 24.
Ctenizidse, 226.
Ctenophoi'a, 52, 475.
Cubex, 50.
Cucullanus, 453.
Cucumaria, 312.
Culicidee, 50.
CWa, 273.
Cumacea, 272.
Curculionidaz, 149.
Cuspidariidse, 418.
Cuttle- Fish, 328.

572

INDEX.

Cuvicrina, 368.
Cyamidae, 278.
Cyamus, 279.
Cyathocrinus, 301.
Cyatliopoma, 390.
Cyclatella, 464.
Cyclica, 156.
Cyclonassa, 378.
Cyclophoridm, 389.
Cyclophorus, 390.
Cyclopides, 92.
Cyclops, 283.
Cyclorrhapha, 61.
Cyclostoma, 389.
Cydostomata, 423.
Cydostomatidae, 389.
Cydippidae, 476.
Cylindrella, 347.
Cylindrellidm, 347.
Cyllene, 377.
Cyrnatophoridae, 100.
Cymbium, 374.
Cymbulia, 368.
Cymbuliidte, 368.
Cymbuliopsis, 369.
Cymothoidaz, 275.
Cynipidae, 18.
Cynips, 21.
Cyphus, 417.
Cypraea, 383.
Cyprazidaz, 383.
Cypridina, 283.
Cyprinidae, 410.
Cypris, 283.
Cyrena, 414.
Cyrestis, 86.
Cysticerctis, 462.
Cystidea, 295.
Cystosoma, 279.
Cythara, 372.
Cythere, 283.

Dacus, 71.
Dactylocotyle, 466.
Daddy Longlegs, 52.
Danainaz, 84.
DapJmia, 284.
Darwinella, 545.
Dasychira, 107, 110.
Dasypoda, 42.
Date-Shells, 406.
Death's-Head Moth, 96.
Death-Watch, 146.
Decapoda, 255, 328, 333.
Deer-Tick, 75.
DeilepMla, 98.
Delphimila, 396.
Delphinulidee, 396.
Demodex, 246.
Demodicidse, 246.
Demospongia. 539.
Dendroccda, 471.
Dendrocystis, 297.
Dendronotus, 356.
Dendrophyllia, 507.
Dentaliidae, 400.
Dentalium, 400.
Depressaria, 121.
Dercas, 92.
Dermanyssus, 244.
Dermaptera, 186.
Bermestes, 139.

Desidw, 229.
Desmestidse, 139.
Desmonota, 157.
Dcsoria, 302.
Dcxiobraiicheea, 366.
Diadema, 310, 312.
Diastilis, 273.
Diastrophus, 21.
Dibranchiata, 328.
Diceras, 415.
Dicranura, 99.
Dicyemidze, 473.
Difflugia, 553.
ZMo&a, 100.
Dioctria, 60.
Diplopoda, 204, 208.
Diplozoum, 465.
Diplnridm, 225.
Diporpa, 466.
Diptera, 47.
Dipthera, 112.
Diseomednsse, 493.
Distomeaz, 467.
Distomum, 467.
Doehmius, 453.
Docoglossa, 397.
Dog-Whelks, 377.
Dolium, 382.
Dolomedes, 234.
Donacidae, 413.
Donoxinm, 155.
Donax, 413.
Dondersia, 400.
Dor-Beetle, 142.
Dorididm, 354.
Doridopsidse, 354.
Dorippe, 260.
Dorippidas, 260.
Boris, 354.
Doryerinus, 302.
Dosinia, 413.
ZMo, 356.
Double- Worm, 465.
Dove-Shells, 378.
Dragon-Flies, 167.
Drassidas, 228.
Dreissensict,, 412.
Dreissensiidas, 412.
Drepanulidaz, 104.
Drillia, 372.
Drinker-Moth, 104.
Dromia, 261.
Drone-Flies, 62.
Dynastes, 143.
Dysdera, 227.
Dysderidm, 228.
Dytiscidai, 133.
Dytiscus, 134.

Earwigs, 186.
Earth-Worms, 439.
Eastonia, 413.
.B&uKo, 260.
Eburna, 377.
Echinarachniits, 309.
Eehiiwcoccus, 463.
Echinodermata, 289.
Echinoidea, 308.
Echinometra, 311.
Echinomyia, 70.
Echinorhynchus, 448.
Echinosphaera, 295, 296.

Echinothuridx, 311.
Echiurus, 444.
Ectobia, 186.
Ectoproda, 421.
Edriophthalmata, 272.
Elampus, 27.
Elaphomyia, 72.
Elaphrus, 131.
Elateridw, 142.
Eledone, 330.
Eleutheria, 484.
Eloadis, 500.
j%sra, 359.
Emarginula, 396.
Emperor- Butterflies, 87.
Emperor-Moths, 93.
Empis, 60.
Endoproda, 425.
Enoplus, 449.
Eiitoconcha, 360.
Entomostraca, 280.
Eophrynus, 240.
Ephemera, 171.
Ephemeridm, 169.
Ephialtes, 24.
Ephydatia, 544.
Ephyra, 495.
Epibdella, 464.
Epiblemum, 234.
Epicaridea, 275.
Epilachna, 158.
Epinephele, 88.
Epistylis, 566.
J^izoa, 283.
Erebia, 88.
Ergates, 153.
Eristalis, 62.
Erraiitia. 433.
Eryeina, 88.
Erycinidie, 88.
Eryontidw, 267.
Esperiopsis, 542.
Eucharis, 475, 476.
Euchroma, 142.
Eucopepoda, 283.
Eudiocrinus, 300.
Euglypha, 553.
Eulamcllibranchiata, 410.
Eidimidm, 392.
Eumenidse, 40.
Eupagurus, 262.
Euphausiidaz. 272.
Eupithecia, 117.
Euplcea, 84.
Eupledella, 537, 538.
Eupoda, 155.
Eurydema, 188.
Eurygaster, 188.
Eurypterus, 251.
Euscorpius, 216.
Euspongia, 545.
Euspongilla, 544.
Exdhalia, 87.
Euthria, 377.
Evaniidse, 26.
Exenterus, 23.
Extracrinus, 302.

False Scorpions, 237.
False Spiders, 235.
Farrea, 539.
Fasciolaria, 375.

INDEX.

573

Fasciolariidm, 375.
Faunus, 386.
Feather-Star, 299.
Figitcs, 21.
Fig-Shells, 383.
File-Shells, 409.
Filibranchiata, 404.
Filistata, 228.
Filistatidx, 228.
FMtelarix, 228.
Firoloida, 374.
Fish-Lice, 283.
Fissurella, 396.
Fissurellidm, 396.
Flabellifera, 274.
Flabellum, 505.
Flagellata, 593.
i^toa, 194.
Flat- Worms, 459.
Fleas, 75.
Flesh-Fly, 67.
Fleshy Sponges, 541.
Flies, 47, 64.
Floscularia, 447.
Flustra, 420, 422.
Foraminifera, 554.
Forest- Flies, 74.
Forficula, 186.
Forficulidm, 186.
Formica, 30.
Formicidse, 27.
Four-Rayed Sponges, 540.
Fresh- Water Shrimps, 277.
Fresh-Water Sponges, 544.
Fritillaries, 84.
Frog-Hoppers, 195.
Fulgoridse, 194.
Fulgur, 376.
Fungus-Animals, 553.
Fungia, 506.
Fungiidw, 506.
Fungus-Midges, 52.
Fusus, 376.

Gad-Flies, 72.
Gadiniidee, 364.
Galeodes, 236.
Galeomma, 410.
Galeommidse, 410.
Galleria, 118.
Gall-Midges, 56.
Gall- Wasps, 18.
Gamasidee, 243.
Gamasus, 244.
Gammaridea, 277.
Gammarus, 277.
Gapers, 415.
Garypus, 238.
Gastrma, 496.
Gastracanlha, 232.
Gastroch&na, 416.
Gastrochae.nid.ee, 416.
Gastropacha, 104.
Gastrophilus, 72.
Gastropoda, 341.
Gastropteron, 363.
Gastrula, 496.
Gecarcinidee, 257.
Gecarcinus, 257.
Gelasimus, 258.
Geodephaga, 129.
Geodesmus, 471.

Geocorisa, 188.
Gcodia, 540.
Geomelania, 390.
Gcomelridee, 114.
Geophilidm, 208.
Geoplana, 471.
Geotrupes, 142.
Gephyrea, 444.
Gerris, 191.
Ghost-Moths, 103.
Giganiostraca, 248, 249.
Glass-Sponges, 536.
Glass-Rope Sponge, 538.
Glandina, 343.
Glaucus, 356, 359.
(?^6a, 369.
Globigerina, 557.
Globigerinidte, 557.
Glomeridae, 210.
Glomeridesmidee, 210.
Glomeridesmus, 210.
Glomeris, 213.
Glossina, 68.
Glow- Worm, 145.
Glyeera, 435.
Glyptosphmra, 295, 296.
Gnathia, 274.
Gnathiidae, 274.
Gnathophausia, 272.
Gnats, 50.
Goat-Moth, 103.
Goliath Beetle, 143.
Goliaihus, 143.
Goniodoris, 355.
Goniurus, 92.
Gonyleptidae, 240.
Gordiidae, 455.
Gordius, 455.
Gorgonia, 515.
Gorgoniidae, 514.
Greeophcmus, 220.
Grafilla, 470.
Grantia, 535.
Grapholitha, 120.
Grapsidae, 258.
Grasshoppers, 178.
Graylings, 88.
Gregarina, 564.
Gromia, 554.
Gryllidae, 176.
Gryllotalpa, 177.
GVyZZws, 177.
Gymnoglossa, 392.
Gymnoleemata, 422.
Gymnosomata, 366.
Gyrinidw, 134.
Gyrinus, 134.

Habrosync, 100.
Hadena, 111.
H&ckelia, 476.
Hsematopota, 59.
H&mobaphes, 283.
Hairstreaks, 89.
Hair- Worms, 455.
Halaearidm, 243.
Halictus, 42.
Haliotidm, 369.
Haliotis, 369.-
Haliphysema, 555.
Halobates, 191.
Halopsyche, 366.

Hamitcs, 340.
Hammer-Oyster, 408.
Harpa, 373.
Harpax, 184.
Harpidm, 373.
Harp-Shells, 373.
Harvest-Spiders. 238.
Hawk- Moths, 95.
Hedychrum, 27.
ffelicarion, 344.
ffelicenidw, 395.
Helicidm, 345.
Helicopsychc, 161.
Helicostyla, 347.
Heliosphseria, 562.
Heliothrips, 202.
Heliozoa, 559.
#efe, 345.
Hemiaspis, 251.
Hemiaster, 319.
Hemiophrya, 568.
Henicops, 205.
Hepialidse, 103.
Hepialus, 103.
Hercules- Beetles, 143.
Hermella, 436.
Hermione, 434.
Hermit- Crabs, 261.
Hcrpetocrinus, 299.
Hesperia, 92.
Hesperiidse, 92.
Hessian Fly, 56.
Heteroccela, 535.
Heterocera, 92.
Heterodera, 451.
Heteromera, 147.
Heteronereis, 433.
Heteropoda, 232, 392.
ffeteropodidee, 232.
Hetrodes, 179.
Hexabranchus, 355.
Hexactinellida, 536.
Hexactinia, 500.
Hexarthra, 447.
Hexisopus, 237.
Hibemia, 115.
Hipparchia, 88.
Hippobosca, 75.
Hippoboscidse, 74.
Hipponychidse,, 390.
Hipponyx, 390.
Hippopus, 415.
Hippospongia, 546.
Hippuritidae, 414.
ffirudiiiea, 441.
Hirudo, 441.
Hispinx, 157.
.ERster-, 139.
Histeridsz, 138.
Holopus, 300.
Holothuria, 312.
Holothuroidea, 312.
Holothyrus, 244.
Homalium, 135.
Homocazla, 535.
Honey-Bee, 38, 45.
Hormiphora, 476.
Hornet, 41.
Horny Corals, 510.
Horny Sponges, 545.
Horse'-Flies, 58.
Horse-Sponge, 545.

574

INDEX.

Hotinus, 149.
House-Fly, 64.
Hover-Flies, 62.
Humble- Bee Flies, 62.
Humble -Bees, 46.
Hyaloeylix, 368.
Hyalonema, 538.
Hydra, 491.
Hydrachinidse, 243.
Hydractinia, 487.
Hydrobiidee, 387.
Hydrocorallia, 488.
Hydrocorisa, 192.
Hydrodephaga, 129.
Hydromedusm, 484.
Hydrometridse, 191.
Hydrophilidae, 140.
Hydropsy chidae, 162.
Hydroptilidae, 162.
Hylseus, 42.
Hylobius, 149.
Hylotoma, 17.
Hylotrupes, 154.
Hymenoptera, 11, 14.
Hypenidse, 118.
Hyperammina, 555.
Hyperina, 279.
Hyperotus, 417.
Hypochilidae, 227.
Hypochilus, 227.
Hypoderma, 73.
Hyponomeuta, 122.
Hypsidm, 111.
Hyptiotes, 230.
Hystricrinus, 302.

Ianthella, 545.
Iaiithina, 392.
Ianthinidae, 391.
Ibacus, 263.
Ibalia, 21.
ic<?ri/a, 200.
Ichneumon, 24.
Ichneumon- Wasps, 23.
Ichneumonidae, 23.
Idalia, 355.
/dotea, 273.
Idoteidm, 273.
Illoricata, 446.
Imperforata, 554.
Ineequipalpia, 162.
Inferobranchiata, 355.
Infusoria, 562.
Insects, 1, 5.
Jo, 386.
Iphigenia, 413.
Isidogorgia, 515.
/si's, 516.
Ismenia, 400.
Isocardia, 410.
Isopoda, 273.
issws. 195.
Iulidse, 211.
luridse, 215.
Ixodes, 244.
Ixodidae, 244.

Javelin-Wasp, 26.
Jelly-Fish, 474, 481.
Jigger, 76.
Jumala, 376.
Junonia, 86.

King-Crabs, 248, 249.
Kitten-Moth, 100.
Kcenenia, 220.

Labidura, 187.
Lace-Corals, 420.
Lace- Wing Flies, 166.
Lachnus, 198.
Lac Insect, 200.
Lackey-Moth, 107.
Lacuna, 387.
Ladybirds, 158.
Lsevicardium, 414.
Lagena, 556.
Lambidium, 382.
Lamellicornia, 141.
Lamia, 154.
Lamp-Shells, 427.
Lampyridse, 145.
Lampyris, 145.
Land-Bugs, 188.
Land-Crabs, 256.
Laniatores, 240.
Lanistes, 389.
Lantern-Flies, 194.
Lappet-Moth, 104.
Larentia, 117.
Lasia, 158.
Lasiocampidae, 104.
Lasius, 136.
Laterigradee, 232.
Lathrodectus, 230.
Latirus, 375.
Leaf-Cutter Bees, 43.
Leaf- Fleas, 195.
Leaf-Insects, 182-
Leander, 269.
Ledra, 295.
Leeches, 441.
Lepadocrinus, 296, 304.
Zepas, 280.
Lepeta, 297.
Lepeditae, 397.
Lepidomenia, 400.
Lepidoptera, 77.
Lepidoteuthis, 336.
Lepidurus, 285.
Lepisma, 203.
Lepralia, 420, 423.
Leptinotarsa, 157.
Leptoceridm, 162.
Leptoconchus, 380.
Leptodora, 285.
Leptonidse, 410.
Leptopenus, 506.
Leptopoma, 390.
Leptostraca, 280.
Lepturides, 153.
Lemma, 283.
Lernseonema, 283.
Leucifer, 271.
Leucopsis, 22.
Leucosiidee, 260.
Leucosolenia, 535.
Leucozonia, 375.
Libellula, 168.
Libellulidm, 168.
Lice, 201.
Ligia, 276.
Lima, 409.
Limacidse, 344.
Limacina, 367.

Limacinidae, 367.
Limacodidae, 104.
Limapontia, 359.
Limax, 344.
Limenitis, 86.
Limidee, 409.
Limneea, 350.
Limneeidae, 350.
Limnobates, 191.
Limnochares, 243.
Limnophilus, 161.
Limnoria, 275.
Limopsis, 405.
Limpets, 397.
Limulidm, 251.
Limulus, 249.
I»a, 157.
Linguatulina, 247.
Lingula, 431.
Lingulidae, 431.
Linotaenia, 208.
Linyphiidae, 230.
Liphistiidae, 224.
Liphistius, 224.
Liponema, 502.
Lipoptena, 75.
Lithistida, 540.
Lithobius, 205.
Lithodomus, 406.
Littorina, 386.
Littorinidae, 386.
Liver-Fluke, 467
Lobiger, 364.
Lobosa, 552.
Lobster-Moth, 99.
Lobsters, 253, 263.
Locusta, 179.
Locustialse, 178.
Locusts, 179.
Loliginidae, 334.
Zo%o, 334.
Lomechusa, 135.
Looper-Moths, 114.
Lophogaster, 272.
Lophyrus, 16, 23.
Loricata, 446.
Lowest Animals, 550.
Loxosoma, 425.
Lucanidae, 140.
Lucanus, 141.
Lucapina, 397.
Lucernaria, 495.
Lucicola, 145.
Lucilia, 67.
Lucinidm, 410.
Lufforia, 545.
Lumbricidae, 439.
Lumbricus, 439.
Lycaena, 89.
Lycsenidse, 88.
Lycidae, 144.
Lycosidae, 233.
Lyda, 16.
Lygaeidee, 189.
Lygaeus, 189.
Lymantria, 107.
Lymantriidae, 107.
Lymnophilidae, 162.
Lysiosquilla, 111.
Lythria, 11 7.

Machilis, 203.

INDEX.

575

Macrochira, 259.
Macrodontia, 153.
Macroglossa, 98.
Macropodia, 259.
Macrura, 261.
Mactra, 413.
Mactridm, 413.
Madrepores, 507.
Magilus, 380.
Magpie-Moth, 116.
Jlfata, 259.
Malacdbdella, 458.
Malacodermata, 144
Malacostraca, 254.
Malletia, 404.
Malleus, 408.
Mallophaga, 176.
Mangilia, 372.
Mango-Butterflies. 87.
Mantidae, 183.
Mantis, 184.
Mantis- Flies, 164.
Mantispidw, 164.
Mantis-Shrimps, 272. .
Map- Butterfly, 86.
Marginella, 374.
Marginellidse, 374
Marsupites, 299.
Martesia, 416.
Masaridae, 40.
Mason-Bees, 42.
Matutidae, 259.
May-Flies, 163, 169.
Meal-Moth, 118.
Meal -Worm, 147.
Meandrina, 510.
Meekelia, 457.
Meconema, 179.
Medusse, 492.
Megachile, 42.
Megalasma, 281.
Megalatractus, 376.
Megalomostonxa, 390.
Megaloptera, 164.
Melanargia, 88.
Mclania, 386.
Melaniidee,, 386.
Melanippe, 177.
Melanopsis, 386.
Melantho, 388.
JfeZ^e, 356.
Meleagrina, 407.
Melicerta, 447.
Meligethes, 139.
Melina, 408.
Melipoma, 45.
Meliteea, 86.
Mellinus, 35.
JlfeWe, 148.
Meloidm, 147.
Melongena, 376.
Melolonlhinse, 142.
Mermis, 456.
Mermithidw, 456.
Merostomata, 251.
Mesites, 295.
Mesodesmatidm, 413
Mesostenus, 24.
Mesostomum, 469.
Mesothelm, 223.
Miastor, 57.
Microch&ta, 439.

Microgaster, 26.
Microlepidoptera, 118.
Midges, 52.
Miliolina, 554.
Millericrinus, 299.
Millipedes, 204, 208.
Milneria, 410.
Mites, 241.
Jf#ra, 375.
Mitridm, 375.
Moggridgea, 226.
Mole-Crickets, 177.
Mollusca, 320.
Molluscoidea, 419.
Molorchides, 153.
Monads, 563.
Mormxonida, 541.
Monera, 552.
Monocaulus, 487.
Monoxenia, 496.
Jfon'o, 382.
Mormolyce, 132.
Morpho, 87.
Mosquitoes, 50.
Moss-Animals, 419.
Moths, 77, 92.
Mud-Wasps, 40.
Mulinia, 413.
Murex, 379.
Murieantha, 379.
Muricidae, 378.
Musca, 64.
Muscidse, 64.
Musk-Beetle, 153.
Mussels, 405.
Mutelidae, 410.
Mulilla, 32.
Mutillidse, 32.
i/ya, 415.
Myacea, 415.
Myadora, 417.
Mycetophilidm, 52.
Mycetopus, 411.
Mycetozoa, 553.
i/i/efas, 60.
Myidw. 415.
Myochama, 417.
Myocoptcs, 246.
Myrmecocystus, 31.
Myrmeleon, 165.
Myzostoma, 440.
Myzostomatidaz., 440.
Myrmelontidm, 165.
Myrtale, 226.
Mysidee, 272.
Jfi/sw?, 272.
Mytilidaz, 405.
Mytilus, 405.

Naclia, 101.
Nais, 440.
iVassa, 378.
Nassidee, 377.
JVatica, 391.
Naticidae, 391.
Nauplius, 253.
Nausitoria, 417.
Nautilidm, 338.
Nautilus, 339.
Nebalia, 280.
Nebaliopsis, 280.
Necrophaga, 135.

Necrophorus, 137.
Necydalis, 154.
iVeirfes, 189.
Nematocera, 58.
Netnatohelminthes, 448.
Nematoidea, 449.
Nematoxys, 449.
JVemeobius, 88.
Nemertinea, 457.
Nemesia, 226.
Nemobius, 177.
Nemopteridee, 164.
Neobuccinum, 377.
Neomenia, 400.
Neomeniidae, 400.
Neothauma, 388.
iVepa, 192.
Nephelis, 443.
Nephrops, 264.
Nephrosidm, 264.
Nepidse, 192.
Neptune's Cup, 543.
Nereidae, 434.
Nereis, 434.
iVm'ta, 395.
Neritidas, 395.
Neritina, 395.
Neuronia, 113.
Neuroptera, 159.
Newportiidm, 206.
Nisoniades, 92.
Nitidulidse, 139.
Nodiluca, 564.
Noctuidse, 111.
iVops, 227.
Noteus, 446.
Notiophilus, 131.
Notodonta, 100.
Notodontidee, 99.
Notommata, 446.
Notonecta, 193.
Notonectidse, 193.
Nucleobranchiata, 392.
Nucula, 403.
Nuculidm, 403.
Nuculina, 404.
Ntodibranchiata, 353.
Nummulites, 559.
Nycteribia, 75.
Nycteribiidse, 73.
Nyctiphanes, 271.
Nymphalidae, 84.

Oak-Eggar, 104.
Obisiidse, 238.
Obisium, 238.
Ocneria, 107.
Octactinia, 511.
Octopoda, 328.
Octopodidae, 328.
Octopus, 328.
Oculati, 191.
Ocypoda, 257.
Ocypodidaz, 257.
Oeypus, 135.
Odonata, 167.
Odonestis, 105.
Odynerus, 40.
(Ecodoma, 32.
(Estridm, 72.
ffi&nis, 73.
Oil-Beetles, 148.

576

INDEX.

Oligocheeta, 439.
Oliva, 373.
Olive-Fly, 71.
Olivella, 373.
Olives, 373.
Olividee, 373.
Ommatostrcphes, 334.
Omphalotropis, 390.
Oncidiidaz, 349.
Oniscoidea, 275.
Oniscus, 276.
Onychoteuthidse, 337.
Onychoteuthis, 337.
Oonopidse,, 228.
Ophiactis, 315.
Ophiothrix, 307.
Ophiuroidea, 306.
Opiliones, 238.
Opisthobranchiata, 352.
Opisthoporus, 390.
Opisthophthalmus, 216.
Opisthothelm, 224.
Orbitelarise, 230.
Orbitolites, 556.
Organ- Pipe Coral, 517.
Orgygia, 107.
Oribatidas, 245.
Ormers, 396.
Ornithocloninw, 225.
Omithomyia, 75.
Ornithoptera, 91.
Ortalis, 72.
Orthesia, 199.
Orthoceras, 339.
Orthoceralidae, 339.
Orthonectidae, 473.
Orthoptera, 159, 166.
Orthorrhapha, 50.
Osmia, 42.
Ostracoda, 282.
Osirea, 408.
Ostreidse, 408.
Otopoma, 389.
Oywfo, 383.
Owl-Moths, 111.
Oxopsei, 218.
Oxybelus, 36.
Oxygyrus, 394.
Oxynoidse,, 364.
Oxyrhyncha, 259.
Oxystomata, 259.
Oxyuris, 453.
Oysters, 408.

Pachymerus, 16.
Pachytylus, 181.
Painted Lady, 86.
Palazoblattina, 166.
Palsemon, 269.
Palsemonidaz, 269.
Palseophonus, 215.
Palinuridae, 263.
Palinurus, 263.
Pafofo, 434.
Palpatores, 240.
Palpicomes, 140.
Palpigradi, 220.
Paludicella, 422, 424,
Palystes, 232.
Palythoa, 503.
Pamphila, 92.
Pandalidae, 270.

Pandalus, 270.
Pandora, 417.
Pandoridse, 417.
Panorpa, 163.
Panorpidee, 162.
Pantopoda, 248.
Papilio, 91.
Papilionidaz, 91.
Paramenia, 400.
Paranebalia, 280.
Pararge, 88.
Parasita, 360.
Parastacidm, 268.
Parthcnopea, 282.
Parthenopidm, 260.
Passalidse, 141.
Patella, 397.
Patellidae, 397.
Pauropoda, 213.
Paussidse, 136.
Paussus, 136.
Peacock-Butterfly, 85.
Pea-Moth, 120.
Pearl-Mussel, 412.
Pearl-Oysters, 407.
Pecten,, 409.
Pectinibranchiata, 370.
Pectinicornia, 140.
Pectinidse, 409, 485.
Peck's, 485.
Peduneulns, 405.
Pedalium, 447.
Pedicularia, 384.
Pediculina, 201.
Pedipalpi, 217.
Pelagothuria, 313.
Pelecypoda, 401.
Pelican's Foot, 385.
Pellibranchiata, 359.
Pelomyxa, 552.
Peltogaster, 282.
Penseidea, 270.
Penazus, 270.
Peneroplis, 556.
Pennatula, 513.
Pennatulidse, 511.
Pennella, 283.
Pentacrinus, 298.
Pentamera, 129.
Pentastomida, 247.
Pentastomum, 247.
Pentatoma, 188.
Pentatomatidse, 188.
Pentremites, 303.
Pepper- Moth, 114.
Peraclis, 367.
Perforata, 554.
Peripatidae, 287.
Peripatoides, 288.
Peripatopsis, 288.
Peripatus, 288.
Periphragella, 539.
Periphylia, 494.
Periplaneta, 185.
Periwinkles, 386.
Perfo, 172.
Perlidm, 171.
Petalocrinus, 301.
Petiolata, 17.
Phalangiidas, 241.
Phalangium, 240.
Phalera, 99.

Phascolosoma, 444.

Phasianclla, 395.

Phasmatidse, 182.

Pheronema, 539.

Philanthidae, 36.

Philanthus, 36.

Philine, 363.

Philinidee, 363.

Philodromus, 344.

Phlmobium, 135.

Pholadacea, 416.

Pholadidaz, 416.

Pholadomya, 418.

PActfas, 416.

Pholcidm, 230.

Pholcus, 230.

PAos, 377.

Phreatoicidea, 276.

Phreatoicus, 276.

Phreoryctes, 440.

Phronima, 279.

Phryganeidaz, 161.

Phylactolaemata, 421.

Phyllidia, 355.

Phyllirhde, 358.

Phyllium, 183.

Phyllodoce, 434.

Phyllodromia, 185.

Phyllopoda, 285.

Phyllotreta,>157 '.

Phylloxera, 197.

Phymosoma, 444.

Physa, 351.

Physalia, 482.

Physidse, 350.

Physophora, 481.

Physophoriolse, 483.

Physopsis, 351.

Phytocoridee, 190.

Phytocoris, 190.

Phytophaga, 155.

Phytoptidm, 246.

Phytoptus, 246.

Pilidium, 458.

Pilocystis, 297.

Pimpla, 25.

Pimplariinm, 24.

Pine-Moth, 112.

Pinnoctopus, 331.

Pinnothcridas, 259.

Piophila, 72.

Pmt/a, 383.

Pisania, 377.

Pisaura, 234.

Pisauridse, 234.

Pisidium, 414.

Placuna, 404.

Plagiost'oma, 410.

Plagitelariaz, 230.

Planar ians, 471.

P/cmes, 259.

Planipennia, 162.

Planorbis, 350.

Plant- Bugs, 190.

Plant-Lice, 196.

Platycrinus, 299.

Platyhelminthes, 459.

Platyparea, 71.

Platyrrhachus, 212.

Pleurobranchidm, 364.
I Plev,robranchus, 364.
I Pleurophyllida, 355.

INDEX.

577

Plcurotoma, 372.
Plcurotomaria, 396.
Plcurotomariidx, 396.
Plcurotomidse, 372.
Plocamophortis, 355.
Ploima, 446.
Plume-Moths, 122.
Plutonium, 206.
Pncumoderma, 366.
Pneumora, 182.
Podoaccrus, 278.
Podura, 203.
Paecilotheria, 224.
PoZwi, 458.
Polybranchiata, 356.
Polycai~pinea, 270.
Polycelis, 471.
Polycera, 355.
Polyceridse, 355.
Polychmta, 433.
Polylophus, 539.
Polyomniatus, 89.
Polymorphina, 557.
Polyparinm, 504.
Polyphloca, 100.
Polyphylla, 142.
Polyplacophora, 398.
Polypomedusse, 481.
Polysiphonia, 502.
Polystomem, 464.
Polystomella, 559.
Polyslomum, 466.
Polytremaria, 396.
Polyxenidm, 209.
Polyxenus, 209, 212.
Polyzonium, 211, 213.
Pompilidx, 33.
Pond-Snails, 350.
Pontarachna. 243.
Pontobdella, 444.
Pomtonia, 270.
Pontoniidae, 270.
Porcelain Butterflies, 86.
Porcellana, 261.
Porcellanaster, 296.
Porcellio, 276.
Porocidaris, 310.
Poi-ocrinus, 296, 304.
Poromya, 418.
Poromyidm, 418.
Portloes-ia, 110.
Portuguese Man-of-War, 482.
Portunidm, 256.
Portunus, 256.
Potamides, 385.
Potamobia, 264.
Potamobiidae, 264.
Potato-Beetle, 157.
Poterium, 543.
Pourtalesia, 309.
Prasinidx, 407.
Prawns, 269.
Praying Insects, 183.
Priapulidm, 445.
Priapulus, 445.
Prionns, 153.
Procession-Moth, 106.
Proctotrypidse, 22.
Promachocrinus, 300.
Prominents, 99.
Proncomenia, 400.
Prosobranchiata, 369.

Prostcllaria, 385.
Prostomum, 470.
Proteolepas, 282.
Prolobranchiata, 403.
Protolimulus, 251.
Protomyxa, 552.
Prototracheata, 287.
Protozoa, 550.
Psammobia, 415.
Psammobiidae, 415.
Pselaphidm, 136.
Pselaphognatha, 209.
Pseudidiops, 226.
Pseudolamellibranchiata, 407.
Pscudomarginella, 374.
Pseudoneuroptera, 167.
Pseudophana, 195.
Pseudoscorpiones, 237.
Pseudoterritelariee, 227.
Psocidie, 175.
Psocus, 176.
iWtws, 312.
Psyche, 102.
Psychidse, 102.
Psychropoles, 313.
Ps?/^«, 196.
Psyllidse,, 195.
Ptenoglossa, 391.
Pteroceras, 385.
Ptcrocyclus, 390.
Ptcroides, 513.
Pteromalidee, 21.
Pteromatus, 23.
Pteronotus, 379.
Pteropoda, 365.
Pterophoridee, 122.
Pterophorus, 122.
Pterosoma, 394, 458.
Pterothysanidee, 111.
Pterotrachea, 394.
Pterotracheidse, 394.
Pterygotus, 251.
Ptinidse, 146.
Pdmws, 146.
Pulex, 76.
Pulicidse, 75.
Pulmonata, 342.
Pimicturella, 397.
Pupa, 347.
Pupidae, 347.
Pupina, 390.
Pupipara, 74.
Purpura, 379.
Pusionella, 372.
Puss-Moth, 99.
Pycnogouum, 248.
Pylotoma, 388.
Pyralidee, 118.
Pyrameis, 86.
Pyramidellidm, 392.
Pyraztis, 385.
Pyrocystis, 564.
Pyrophorus, 144.
Pyrrhocoris, 189.
Pythia, 349.

Radiolaria, 561.
Radius, 384.
Ragactis, 500.
Ranatra, 192.
Randla, 381.
Rangia, 413.

Rapana, 380.
Razor-Shells, 415.
Recluzia, 392.
Red Coral, 516.
A'cc&'a, 468.
Reduviidm, 191.
Reduvius, 191, 244.
Requienia, 415.
Rctepora, 420, 423.
Retina, 119.
Retitelarise, 230.
Rhabditis, 451.
Rhabdoccda, 469.
Rhabdoliths, 557.
Rhabdonema, 451.
Rhachiglossa, 372.
Rhagium, 154.
Rhaphidia, 163.
Ate;, 236.

Rhinoceros- Beetle, 143.
Rhipidius, 147.
Rhipidoglossa, 394.
Rhipidophorida?; 147.
Rhipidophorus, 147.
Rhizocephala, 282.
Rhizochilus, 380.
Rhizocrinus, 298.
Rhizopoda, 552.
Rhizosphsera, 562.
Rhizostoma, 492.
Rhizota, 447.
Rhizotrogus, 142.
Rhodites, 19.
Rhodocera, 92.
Rhopalocera, 83.
Rhopalodina, 313.
Rhopalura, 473.
Rhyacophilidm, 162.
Rhynchites, 150.
Rhynchocinetes, 269.
Rhynchonella, 428, 430.
Rhynchonellidse, 428, 430.
Rhynchophoms, 152.
Rhynchota, 159, 187.
Ricinulei, 241.
Rimula, 397.
Ringicvla, 363.
&», 387.
Rissoidm, 387.
River-Mussels, 411.
Robber-Flies, 59.
Rock-Lobsters, 263.
iteto, 413.
Rotifera, 445.
Round-Worms, 448.
Rove-Beetles, 135.
Rutilia, 71.

Sabclla, 438.
Saccocoma, 301.
Sacculina, 282.
Sagartia, 503.
Sagitta, 457.
Sagra, 155.
/SWcfa, 191.
Saldidse, 191.
Saltigradse, 234.
Sand-Flies, 58.
Sand-Hopper, 277.
Sand-Worm, 435.
Saprinus, 139.
Sarcophaga, 67.

VOL. VI.

-37

578

INDEX.

Sarcopsyllidse, 76.
Sarcop>syllus, 76.
Sarcoptes, 246.
Sarcoptidse, 245.
Soturnia, 94.
Saturniidse, 93.
Saty rinse, 84.
Satyrus, 88.
Saw-Flies, 15, 16.
Saxicava, 415.
Saxicavidse, 415.
Scale-Insects, 198.
Sealaria, 392.
Scalariidse, 392.
Scallops, 409.
Scaphander, 361.
Scaphopoda, 400.
Scarabseus, 142.
Searites, 132.
Schendyla, 208.
Sehistocerea, 181.
Schizochiton, 399.
Schizoglossa, 343.
Schizonotidse, 21 S.
ScMzonotus, 218.
Schizopoda, 271.
Schizostoma, 470.
Sciara, 55.
Scirtopoda, 447.
Scissurella, 396.
Sclerocrangon, 569.
Sclerothamnus, 539.
Scobiculariidee, 413.
(S'coZia, 33.
Scoliidse, 32.
Scolopcndra, 206.
Scolopendrclla, 208.
Scolopendridse, 206.
Scolopocryptopidee, 206.
Scolytidse, 152.
Scorpio, 215.
Scorpion-Flies, 162.
Scorpionidse,, 215.
Scorpions, 204, 214.
Scotoplana, 313.
Scrobicularia, 413.
Scutellera, 188.
Scutibrancliiata, 394.
Scutigera, 205.
Scwtigeridse, 205.
Scutum, 397.
Scylleea, 356, 359.
Scyllaridse, 263.
Scyllaridea, 262.
Scyllarus, 263.
Scyphistoma, 495.
Scyphomedusm, 492.
Sea-Anemones, 474, 495.
Sea- Cucumbers, 312.
Sea-Fans, 514.
Sea-Hares, 363.
Sea- Mats, 420, 422.
Sea- Mouse, 433.
Sea- Pens, 511.
Sea-Slater, 276.
Sea-Spiders, 248.
Sea-Urchins, 308.
Segestria, 227.
Sclenocosmiinm, 225.
Semifusus, 376.
Semperella, 539.
/Sfepm, 337.

Sepiidee, 337.
Sepiola, 336.
Sepiolidse, 336.
Septibranchiata, 418.
Sergesti.dse, 271.
Sericostomatidse, 162.
Serolidce, 274.
Serolis, 274.
Serpula, 438.
Serpulidse, 437.
Sesiidse, 100.
Shelled Slugs, 343.
Shell-Fish, 320.^
Ship-Worm, 417.
Shrimps, 268.
Sialidse, 163.
Sialis, 163.
Sicyonis, 502.
Silk-Spinners, 95.
Silk- Worm, 95.
&ftpAa, 138.
Silphidse, 137.
Silver-Fish, 203.
Simulia, 58.

Single-Rayed Sponges, 541.
<S^o, 376.
Siphonaria, 364.
Siphonariidse, 364.
Siphonophora, 211, 481.
Sipunculus, 444.
Sir ex, 16.
Siricidee, 16.
Sironidse, 240.
Sistrum, 380.
Sitones, 149.
Sitophilus, 151.
Six-Rayed Sponges. 536.
Skippers, 92.
Slimonia, 251.
Slugs, 344.
Smerinthus, 97.
Smicra, 22.
Snails, 345.
Snake-Flies, 163.
Snout- Moths, 118.
Social Wasps, 40.
Solcriidee, 387.
Solarium, 387.
Solenidce, 415.
Solcnomya, 404.
Solenomyidse., 403.
Solifugse, 235.
Solitary Bees, 42.
Solitary Wasps, 40.
Solpuga, 235.
Solpugiolee. 235.
Sparassus, 232.
Spathegastcr; 19.
Spheerium, 414.
Sphmroma, 274.
Sphseromid.se, 274.
Sphmrotherium, 210.
Spihserularia, 452.
Sphegidse, 34.
Sphex, 35.
Sphingidse, 95.
Sphinx, 98.
Spiders, 204, 220.
Spider-Shells, 385.
Spilographia, 71.
Spinach-Moth, 117.
Spirachtha, 135.

Spirifer, 431.

Spiriferidse, 430.

Spirostomum, 568.

Spirostrcptidoe, 211.

Spirostreptus, 212.

Spirula, 338.

Spirulidse, 338.

Spisula, 413.

Spondylidee, 410.

Spondylus, 410.

Spongelia, 542.

Sponges, 526.

Spongicola, 270.

SpongiUidie, 544.

Spongiobranchsea, 366.

Sporozoa, 565.

Squids, 328, 334.

Squilla, 273.

Squillidm, 272.

Stag- Beetle, 141.

Staghorn-Fly, 72.

Staircase-Shells, 387.

Standella, 413.

Staphylinidse, 134.

Star-Fishes, 304.

Stauropus, 99.

Stem Saw-Flies, 15.

Stenopteryx, 75.

Stentor, 567.

Stcphalia, 483.

Stick- Insects, 182.

Stilbum, 26.

St. Mark's Fly, 58.

Stomatopoda, 272.

Stomoxys, 68.

Stone-Flies, 171.

Stone-Lilies, 297.

Strangalia, 153.

Stratiomyidse, 61.

Stratiomys, 61.

Streptaxis, 343.

Strepopomatidm, 386.

Strcp>tocaulus, 516.

Strcptophiurse,, 307.

Strobila, 495.

Strombidee, 384.

Strombus, 385.

Strongylidse, 453.

Strmigylocentrotus, 310, 311, 315.

Strophocheilus, 347.

Struthiolariidee, 385 .

Stylastcridse, 488.

Styliola, 368.

Stylocellns, 241.

Stylogastcr, 64.

Stylommatophora, 342.

Stylonychia, 565.

Stylopidse, 148.

Submytilacca, 410.

Succinca, 349.

Succincidse, 348.

Sun- Animalcules, 559.

Surcula, 372.

Swallow-Tails, 91.

Swift Moth, 103.

Sycandra, 535.

Sycon, 536.

Sycotyp>us, 376.

Synapta, 312.

Synergies, 21.

Syngamus, 454.

Syntomidee, 101.

INDEX.

579

Syntomis, 101.
Syromastcs, 189.
Syrphidte, 62.
Syryhut, 62.

Tabanidm, 59.
Tabanus, 59.
Tachina, 70.
Taenia, 459.
T&nioglossa, 380.
Taifed Wasps, 16.
Talitrus, 277.
Tanais, 276.
Tapes, 414.
Tape-Worms, 459.
Tarantula, 233.
Tarantulidse, 220.
Tectibranchiata, 360.
Tegenaria, 230.
2Wras, 22.
Telcgonus, 92.
Telephoridse, 145.
Telephonis, 146.
Tcllina, 413.
Tellinacea, 412.
Tellinidm, 412.
Tenebrio, 147.
Tcnebrionidae, 147.
Tenthredinidm, 16.
Tenthredo, 17.
Terns, 21.
Tcrebella, 437.
Terebellidse, 437.
Terebclhtm, 385.
Tercbra, 371.
Tcrcbratida, 428.
Tcrebratididse, 427.
Tcrebratulina, 427.
Terebridm, 371.
Tcrafo, 417.
Ternies, 175.
Termites, 172.
Tcrmitidx, 172.
Tessera, 495.
Tesseridse, 495.
Tcstacclla, 343.
Testacellidse, 343.
Testicar dines, 427.
Tethys, 356.
Tetrabranchiata, 338.
Tetracha, 130.
Tetractinellida, 540.
Tetragnatlia, 232.
Tetramera, 149.
Tetranychidse, 242.
Tetranychus, 243.
Teirasoma, 45.
Tetrastemma, 457.
Tcttiginse, 182.
retti'ar, 182.
Thalamita, 256.
Thalassinidea, 262.
Thaumastochelys, 262.
Thecalia, 410.
Thecidium, 428.
7%ecfr«, 99.
Thccocyathus, 505.
Thccosomala, 369.
Thelyphonidm, 218.
Thelyphonus, 218.
Thelphusa, 257.
Thelphusidse, 259k

Thcraphosidve, 224.
Thcridiidie, 230.
Thcrmophila, 203.
Thiolficrcrimis, 299.
Thomisidse, 232.
Thorny Oyster, 410.
Thracia, 418.
Thread-Worms, 448.
Zftrips, 202.
Thyatira, 100.
7%ra, 390.
Thyrididie,10i.
Thyris, 104.
Thysanoptera, 201.
Thysanozonm, 472.
Thysanura, 202, 203.
Thyunidse, 32.
Ticks, 241.
Tiger- Beetles, 130.
Tiger-Moths, 111.
TiHea, 120.
Tineidm, 120.
Twi^s, 190.
Tiniageriidm, 101.
Tinopalpus, 91.
Tiphobia, 386.
Tipula, 52.
Tipulidx, 52.
Titanus, 153.
2%pa, 215.
Toilet-Sponge, 545.
Tooth-Shells, 400.
Torinia, 387.
Tortoiseshells, 85.
Tortricidm, 118.
Tortrix, 119.
Toxoglossa, 370.
1'oxotus, 153.
Trachea, 112.
Trap-Door Spiders, 226.
Trematoda, 463.
Trcmoctcpus, 331.
Trepang, 314.
Triarthrus, 252.
Trichilium, 109.
Trichina, 454.
Trichodes, 146.
Trichoptera, 159.
Trichopterygidse, 138.
Tridacna, 415.
Tridacnidse, 414.
Trigona, 45.
Trigonia, 405.
Trigoniidm, 405.
Trilobites, 252.
Trimera, 158.
Triopa, 355.
Tripeltis, 218.
Tn'toi, 381.
Tritonia, 356.
Tritonidw, 381.
Tritonidea, 377.
Tritoniidse, 355.
Trochidse, 395.
Trochopus, 464.
Trochotoma, 396.
Trochus, 395.
Trochocystis, 297.
Troguhis, 241.
Trombidiidx, 242.
Tromhidium, 242.
Trumpet-Animalcules, 56/

Truncatella, 390.
Truncatellidiv, 390.
Trypetinm, 71.
Tryphoninse, 23.
Trypoxylon, 35.
Tryxalium, 180, 182.
Tsetse Fly, 68.
Tubicinella, 282.
Tubicola, 435.
Tubi/ex, 440.
Tubipora, 516.
Tubiporidse,, 517.
Tubitclarise, 228.
Tubulipora, 423.
Tudora, 390.
Tulip-Shells, 375.
Tun-Shells, 382.
Turbellaria, 469.
Turbinclla, 375.
Turbincllidm, 375.
Turbinidsz, 395.
rwr&o, 395.
Turnip-Flea, 157.
Turris, 375.
Turrilites, 340.
Tussock-Moth, 110.
Tyleuchxis, 450.
Typtmi, 270.
Tyroglyphus, 245.

Uintacrinus, 299, 301.
Uloboridse, 230.
Uloborus, 230.
Umbellitclarise, 227.
Umbellula, 513.
Umbrella, 364.
Umbrellidm, 364.
£7?M0, 411.
Unionidse, 410.
Uropygi, 217.
Ultimas, 384.

Valifera, 273.
Valvata, 388.
Valvatidse, 388.
Vanessa, 85.
Velates, 395.
FeMfo, 484.
Velellidse, 483.
Fc/m, 191.
Vclletia, 350.
Vcneracea, 413.
Veneridse, 413.
Ventriculites, 539.
Venus, 413.

Venus' Flower- Basket, 538.
Venus' Girdle, 476.
Veretillum, 511.
Vermetidse, 386.
Vcrmipsylla, 76.
Vertigo, 347.
Vespa, 41.
Vespidw, 40.
Vinegar-Eel, 449.
Violet Snails, 391.
Vitrea, 345.
Vitrina, 344.
Vivipara, 388.
Viviparidm, 388.
Volucella, 62.
To^<to, 374.
Volutharpa, 377.

S8o

INDEX.

Folutidas, 374.
Volutilithes, 374.
VoliUolyria, 374.
Volutomitra, 374.
Volutopsis, 376.
Volvox, 563.
Forte, 470.
Vorticella, 566.
Vulsella, 408.

Waldheimia, 429.
Wall-Browns, 88.
Warbles, 73.
Wasps, 36, 40.
Water-Beetles, 133, 140.
Water-Boatmen, 193.
Water-Bugs, 192.
Water-Flea, 284.
Water-Scorpions, 192.
Water-Spider, 229.

Wax-Moth, 118.
Weevils, 149.
Wentle-Traps, 392.
Whale-Lice, 278.
Wheat- Eel, 449.
Wheel- Animalcules, 445.
Whelks, 376.
Whip-Scorpions, 217.
Whirligig Beetles, 134.
White Admiral, 86.
White Ants, 172.
Willcmsesia, 264.
Wing-Shells, 384.
Wood-Lice, 275.
Worms, 432.
Worm-Shells, 386.

Xcnophoridie, 390.
Xenos, 149.
Xiphosura, 249.

Xylocopa, 43.
Xylophaga, 416.
Xylotrya, 417.

Yetus, 374.
Yoldia, 404.
Ypsilothuria, 313.

Zabrus, 132.
Zelotypia, 103.
Zephroniidse, 210.
Zephroniodesmus, 211.
Zidona, 374.
Zoantharia, 503.
Zonites, 345.
Zygazna, 102.
Zygasnidae, 102.
Zygophiwaz, 307.

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