?Illustrations are indicated by an asterisk

Acanthia lectularia, *188.
Acarina, 230.
Acmara spectorum, *248.
Actinozoa, 97, 102.
Adaptation, 407.
Adder, spreading, 321.
Ægialitis vocifera, 349.
AgalenidÆ, 235.
Agkistrodon piscivorous, 323.
Aix sponsa, 347.
Albatross, 346.
Alca impennis, 345.
Alce americana, *385, 396.
Alligator, 326.
Alligator mississippensis, 326.
Alternation of generations, 96.
Amblophtes rupestris, 282.
Amblystoma, 297, 298.
Amblystoma maculatum, 299.
Ameiurus, 282.
Amoeba, *32;
structure and life of, 31.
Amphioxus, 278.
Anaconda, 324.
Anas boschas, 347.
Anatomy defined, 3.
Anguilla, 284.
Anguillula, 140.
Anolis principalis, 319.
Anosia plexippus, anatomy of larva of, 177;
external structure of, 171, *172;
life of, 175;
mimicked by Basilarchia archippus, *433.
Anseres, 347.
Ant, little black, *224;
little brown, 223.
Antelope, *395, 396.
Antenna of carrion beetle, *184.
Antilocapra americana, *395, 396.
Antrostomus vociferus, 356.
Ant, 212, 218, 223.
Anura, 299.
Ape, 401.
AphidiÆ, 200.
Apis florea, comb of, *222.
Apis mellifica, *218.
Appearance, terrifying, 430.
Aquarium, 457.
Aquarium, battery-jar, *461.
Aquila chrysÆtos, 342.
Arachnida, 144, 229.
Arctomys monax, 391.
Ardea herodias, 358.
Ardea virescens, 347.
Argiope sp., *236.
Argonaut, 257.
Argonauta argo, 257.
Ariolimax californica, *252.
Arthogastra, 230.
Arthropoda, 144.
Ascidian, 259, *261.
Aspidiotus aurantii, *198.
Asterias sp., structure and life of, 108.
Asterias, *109;
cross-section of, *112.
Asterias ocracia, *122.
Asterina mineata, *122.
Asteroidea, 120, 121.
AttidÆ, 235.
Auk, great, 345.
Aves, 327.
Aythya vallisneria, 347.
Ayu, 283.
Back-swimmer, 197, 199.
Balanus, *153.
BalÆna glacialis, 393.
BalÆna mysticetus, 393.
Barbadoes earth, 82.
Barnacle, *153, 155;
sessile, 155;
stalked, 155.
Barn-owl, 353.
Bartramia longicauda, 349.
Bascanium constrictor, 321.
Bass, 282.
Bat, hoary, *392.
Batrachia, 291.
Batrachians, 291;
body form and structure of, 292;
classification of, 295;
life-history and habits of, 295;
structure of, 292.
Bat, 391.
Bead-snake, 322.
Bear, 398.
Beaver, 391.
Bed-bug, *188.
Bee, 212;
solitary, 216.
Beetle, great water-scavenger, 163;
external structure, *164;
internal structure, *167;
antenna of carrion, *184;
Colorado potato, 209.
Beetle, 206;
carrion, 209;
whirligig, 206.
Bell-animalcule, structure and life of, 75.
Bills of birds, 362.
Bipinnaria, 119.
Bird, frigate, 346;
man-of-war, 346;
outline of body showing external regions, *330;
ruby-throat humming, nest and eggs of, *357.
Bird-louse, *194.
Birds, 327;
bills and feet of, 362;
body form and structure of, 336;
care of young, 366;
classification of, 340;
collecting, 466;
determining, 359;
development and life-history of, 339;
feeding habits of, 370;
flight and songs of, 364;
migration of, 367;
molting of, 361;
nesting of, 366;
protection of, 370.
Bird-skins, making, 466.
Bison bison, 396, *397.
Bittern, 348.
Blacksnake, 321.
Blissus leucopterus, 198.
Blood, circulation of, in mammal, *376.
Blood of toad, structure of, 40.
Blow-fly, 201, 202;
section through compound eye of, *185.
"Bob Jordan" (monkey), *400.
Bobwhite, 350.
Bombus, 216.
Bombyx mori, anatomy of larva of, *178.
Bonasa umbellus, 350.
Books, reference, 454.
Borer, peach-tree, *210.
Botaurus lentiginosus, 348.
Box tortoise, 315.
Brachynotus nudus, *153.
Brains of vertebrates, *378.
Branch, defined, 73.
Branta canadensis, 347.
Breeding cage, 458, 459.
Brittle-stars, 120, 121, 122.
Bubo virginianus, 353.
Buffalo, 396, *397.
Bufo lentiginosus, 301;
dissection of, 5.
Bullfrog, 299.
Bumblebee, 216.
Bunodes californica, 103.
Buteo, 353.
Butterfly, external structure of, 171, *172;
life of, 175;
monarch, anatomy of larva of, 177;
dead leaf, *429;
mimicked by viceroy, *433.
Butterflies, 205;
setting-board for, *466, 467.
Buzzard, turkey, 352.
Cachalot, 393.
Cage, lamp-chimney and flower-pot breeding, *459;
soap-box breeding, *458.
Cake-urchin, 124.
Calcarea, 91.
Calliphora vomitoria, 202;
section through compound eye of, *185.
Callorhinus alascanus, *399.
Callorhinus ursinus, parasitized, *422.
Cambarus sp., dissection of, 18;
life of, 146.
Camphephilus principalis, 355.
Cancer productus, *153.
Canis familiaris, 398.
Canis latrans, 398.
Canis nubilus, 398.
Canvas-back, 347.
Carcharodon, 280.
Caribou, 396.
Cassowary, 343.
Castor canadensis, 391.
Caterpillar, apple tent, 208;
forest tent, 209.
Catfish, 282.
Cathartes aura, 352.
Cavia, 390.
Cell, defined, 37.
Cell differentiation, degrees of, 54.
Cell products, 38.
Cell wall, 38.
Centiped, *228, 229;
skein, *228.
Centipeds, 226.
Centrocercus urophasianus, 350.
Centrurus sp., *236.
Cephalpoda, 246.
Cercopithicus, *400.
Cervus canadensis, *394, 395.
Ceryle alcyon, 354.
Cete, 393.
Cetorhinus, 270, 280.
ChÆtura pelagica, 356.
Chain-snake, 320.
Chalk, 81.
Chameleon, green, 318.
Chelonia, 313, 314.
Chelonia mydas, 315.
Chelydra serpentina, 314.
Chen hyperborea, 247.
Chicken-hawk, 353.
Chimney-swift, 356.
Chinch bug, 198.
Chipmunk, 391.
Chiroptera, 391.
Chitin, 145, 158.
Chlorostomum funebrale, *248.
Chordata, 259;
classification of, 260.
Chordeiles virginianus, 356.
Chromatophore, 256.
Chub, 282.
Chrysemys, 314.
Cicada, 199;
seventeen-year, *200;
septendecim, *200, 197.
Circulation of blood in mammal, *376.
Circus hudsonius, 352.
Cistudo carolina, 314.
Clams, 246;
hard shell, 247;
soft-shell, 247.
Class, defined, 73.
Classification, basis and signification of, 65;
defined, 3;
example of, 68.
Clisiocampa americana, larvÆ, *208.
Clisiocampa disstria, caterpillars, *209;
life-history of, 207.
Clupea harengus, 284.
Cobra-da-capello, 324.
CoccidÆ, 198.
Coccyges, 354.
Coccyzus, 354.
Cock, chapparal, 354.
Cockroach, laws of, 436;
local, of birds, 367;
modes of, 437.
Diver, great northern, 343.
Dolphins, 393.
Doris tuberculata, *254.
Draco, 319.
Dragon-flies, 294.
Dragon-fly, *196.
Dragon, flying, 318.
Drawings, 447.
Dryobates pubescens, 355.
Dryobates villosus, 355.
Duck, ruddy, 347.
Dyticus sp., 210.
DytiscidÆ, 207.
Eagle, bald, 352;
golden, 352.
Ear of locust, *187.
Earthworm, anatomy of, *126;
alimentary canal of, *126;
cross-section of, *131;
reproductive organs of, *130;
structure and life of, 127.
Earthworms, 136.
Echinoderm, development of, 119;
structure of, 117;
shape of, 116.
Echinodermata, 108;
classification of, 120.
Echinodoris sp., *254.
Echinoidea, 121, 122, 123.
Eciton, 225.
Ecology, animal, 403.
Ectopistes migratorius, 351.
Eel, 284.
Eft, green, 297;
western brown, *299.
Eggs of birds, collecting, 469.
Eider, 347.
Elasmobranchii, 279.
Elassoma, 271.
Elk, *394, 396.
EpeiridÆ, 236.
Ephemerida, 194.
Epialtus productus, *153.
Equipment of laboratory, 450.
Equipment of pupil, 447.
Erethizon dorsatus, 391.
Erethizon epixanthus, 391.
Eretmochelys imbricata, 215.
Erismatura rubida, 347.
Eumeces skeltonianus, *316.
Eupomotic gibbosuc, dissection of, (facing) *263;
life of, 270;
structure of, 263.
ExocÆtus, 285.
Eye, cornea of compound, of horse-fly, *186;
section through compound, of blow-fly, *185.
Eye of vertebrate, *378.
Falco sparverius, 353.
Family, defined, 72.
Fauna, 440.
Feather-stars, 121, 125, *126.
Feet of birds, 362.
Felis concolor, 398.
FerÆ, 397.
Fever, yellow, and mosquitoes, 205.
Fiber zibethicus, 391.
Fire-flies, 209.
Fishes, 263;
body form and structure of, 271;
classification of, 277;
development and life-history of, 276;
habits and adaptations of, 285.
Fish-hatcheries, 288.
Flat-worms, 137.
Flea, house, *204.
Flickers, 355.
Flies, 201;
chalcid, 214;
ichneumon, 212.
Flight of birds, 366.
Flying fishes, 285.
Food-fishes, 288.
Food of birds, 370.
Foraminifera, 80.
Fox, 398.
Fregata aquila, 346.
Frogs, 299.
Fulica americana, 349.
Fulmars, 345.
Function, defined, 14.
Functions, essential, 15.
Fur-seals, 398, *399.
Fur-seals, parasitized, *422.
Gadus callarias, 284.
Galley-worm, *227.
Gall-flies, 214.
GallinÆ, 350.
Gastropoda, 246.
Gavia imber, 347.
Gavial, 326.
Generation, spontaneous, 58.
Genmules, 85.
Genus, defined, 70.
Geococcyx californianus, 354.
Gephyrean, *134.
Girdler, currant stem, *215.
Glass-snake, 317.
Glires, 391.
Goat, Rocky Mt., 397.
Gonionema vertens, *101.
Goose, Canada, 347.
Gophers, pocket, 391.
Gordius, 140.
Grantia, *47.
Grantia sp., 85.
Grayling, 284.
Grebe,
horned, 343;
pied-billed, 343.
Green, methyl, 351.
Greensnake, 320.
Gregariousness, 410.
Grouse, ruffed, 350.
Grus americana, 348.
Grus mexicana, 348.
Guillemot, 345.
Guinea-pig, 391.
Guinea-worm, 140.
Gull, great black-backed, 345.
Gulls, 345.
Gymnophiona, 302.
GyrinidÆ, 206.
Habitat, 441.
Hag-fishes, 279.
Hair-worms, 140.
HaliÆtus leucocephalus, 352.
Halictus, 216.
Harporhynchus redivivus, *371.
Hatteria, 312.
Hawk, marsh, 352.
Helmet shells, 255.
Heloderma horridum, *317.
Hemiptera, 197.
Hermit-crab, 154, *153.
Herodiones, 347.
Heron,
great blue, 348;
green, 347.
Herring, 284.
Heteredon platirhinos, 321.
Hippocampus hippocampus, *285.
Holothuroidea, 121, 124.
Homo sapiens, 398.
Honey-bee, *218;
brood-cells of, *219;
building comb, *221;
comb of East Indian, *222;
cross-section of body of pupa of, *191.
Honey-bees, 212.
Honey-dew, food of ants, 223.
Hornets, 217.
Horse-fly, cornea of eye of, *186.
House-fly, 202.
Humming-birds, 356.
Hydra, *47;
structure and life of, 46.
Hydrozoa, 96, 97.
HydrophilidÆ, 207.
Hydrophilus sp.,
external structure of, *164;
internal structure of, *167.
Hygrotrechus, 198, *199.
Hyla pickeringii, 300.
Hyla versicolor, 300.
Hymenoptera, 212.
Hyptiotes sp., and web, *238.
Iguana, 318.
Imago, 190.
Injecting-masses, 451.
Insect, pinned, *465;
twig, *427;
wingless, *181.
Insecta, 157.
Insectivora, 391.
Insects, classification of, 191;
collecting, 463;
communal, 215;
development and life-history of, 188;
form and structure of, 181;
killing-bottle for, *463;
social, 215.
Invertebrate, defined, 30.
Islands, coral, 104, 106.
Isopod, *151.
Isopoda, 150.
Jack rabbit, 390.
Janus integer, *215.
Jellyfish, *101.
Jellyfishes, 92;
colonial, 97.
Joint-snake, 318.
Julus, *327.
June-beetle, 212.
June beetles, 206.
Kallima, *429.
Kangaroo, 389.
Katydids, 192.
Kelp-crab, *152.
Kill-deer, 349.
Killing-bottle for insects, *463.
Kingfisher, belted, 354.
Laboratory, equipment of, 450.
Lachnosterna, 212.
Lady-birds, 209.
Lagopus, 350.
Lake-lamprey, 279.
Lampetra wilderi, 279.
Lamprey, *278;
brook, 279.
Lampropeltis boylii, *321.
Lampropeltis getulus, 320.
Lancelet, 278.
Larks, horned, *358.
Larus marinus, 345.
Larva, 189;
of Monarch butterfly, anatomy of, 177;
parasitized, *420.
Lasiurus borealis, 392.
Lasiurus cinereus, *392.
Lasius flavus, 223.
Leeches, 136.
Lemurs, 401.
Leucania unipuncta, *211.
Lepidocyrtus americanus, *181.
Lepidoptera, 205.
Leptocardii, 277.
Leptoplana californica, *138.
Lepus campestris, 390.
Lepus nuttali, 390.
Life-history, defined, 62.
Life-processes, essential, 15.
LimicolÆ, 349.
Limpets, 255, *248.
Littorina scutulata, *248.
Live cages, 457.
Liver of toad, structure of, 41.
Lizard, *309.
Lizards, 316.
Lobster, 151, 152.
Locust, differential, 156;
ear of, *187;
red-legged, 156, *157;
Rocky Mt., 156;
structure and life of, 156;
two-striped, 156.
Locusts, 192.
Loligo, 257.
Longipennes, 345.
Loon, 343.
Lumbricus sp., alimentary canal of, *131;
cross-section of, *132;
structure and life of, 127.
Lung-fish, 285.
Lycena, scales of wings of, *206.
LycosidÆ, 235.
Lynx rufus, 398.
Macrocheira, 194.
Non-calcarea, 91.
Notes, 447, 448.
Notochord, 259.
Notonecta, 197, 199.
Nucleus, 38.
Nudibranchs, 252, *254.
Numenius longirostris, 350.
Nyctea nyctea, 353.
Nycticorax, 348.
Octopi, 255.
Octopods, 256.
Odocoileus americanus, 396.
Odonata, 194.
OligochÆtÆ, 136.
Olor, 347.
Ommatostrephes californica, *257.
Oncorhynchus tschawtscha, 283.
One-celled animals, multiplication of, 57.
Ooze, foraminifera, 81;
radiolaria, 81.
Opheosaurus ventralis, 317.
Ophiuroidea, 121, 122.
Opossum, 389.
Order, defined, 72.
Oreamnos montanus, 397.
Organ, defined, 14.
Orthoptera, 192;
sound-making of, 193.
Orb-web of EpeiridÆ, 236.
Ostrea virginiana, 248.
Ostriches, 341, *342.
Otocoris alpestris, *358.
Ovis canadensis, *383, 396.
Owl, burrowing, 353;
great gray, 353;
great horned, 353;
snowy, 353.
Oyster, 248.
Oyster-crab, 154.
Oyster-drills, 255.
Oysters, 246;
"seed" of, 249;
"spat" of, 249.
Pagurus samuelis, *153.
PaludicolÆ, 348.
Panther, 398.
Paramoecium, *35;
multiplication of, 60;
structure and life of, 34.
Parasitism, 415.
Paroquet, Carolina, 353.
Parrots, 353.
Passer domesticus, dissection of, (facing) *327;
life-history and habits of, 335;
structure of, 327.
Passeres, 357.
Pearl-oyster, *249.
Pelecanus californicus, 346.
Pelecanus erythrorhynchus, 346.
Pelecanus fuscus, 346.
Pelecypoda, 246.
Pelican, brown, 346;
white, 346.
Pentacrinus sp., *126.
Pentacta frondosa, *125.
Peripatus eiseni, *226.
Perla sp., *182.
Petrels, 345.
Petromyzon marinus, *278.
Phalacrocorax, 346.
Pheasants, 350.
Phoca vitulina, 397.
Phoebe, black, nest and eggs of, *340.
Pholas sp., *250.
Phrynosoma, 318.
Phylloxera, grape, 198, 201.
Phylloxera vastatrix, 198, 201.
Phylum, defined, 73.
Physalia sp., *97.
Physeter macrocephalus, 393.
Physiology, defined, 3.
Pici, 354.
Pickerel-frog, 300.
Pigeon, band-tailed, 351;
passenger, 351.
Pinnotheres, 154.
Pipe-fish, 285.
Pisces, 263.
Pituophis bellona, *323.
Planaria sp., *138.
Planarian, fresh-water, *138;
marine, *138.
Planarians, 137.
Plant-lice, 197, 200.
Planula, 96
Platyhelminthes, 137.
Plectrophenax nivalis, *358.
Plethodon, 297.
Plover, field, 349.
Pluteus, 119.
Podilymbus podiceps, 343.
Poison-fangs of rattlesnake, *324.
Pollicipes polymenus, *153.
Polymorphism, 96.
Polynoe brevisetosa, *134.
Polyps, 92, 97.
Pomoxis annularis, 282.
Pomoxis separoides, 282.
Pond-snails, 252.
Porcupine, 390.
Porcupine-fish, 285.
Porifera, 84.
Porpoises, 393.
Porzana carolina, 349.
Prairie-chicken, 350.
Prawns, 152.
Preparations, preserving anatomical, 452.
Primates, 398.
Pristis pectinatis, 281.
Protophyta, 82.
Protoplasm, described, 39.
Protopterus, 288.
Protozoa, defined, 43, 75;
form of, 78;
marine, 80.
Pseudemys, 313.
Pseudogryphus californianus, 352.
Psittaci, 353.
Ptarmigan, 356.
Puff-adder, 325.
Puffins, 345.
Pulex irritans, *204.
Pulmonata, 253.
Puma, 398.
Pumpkin seed, life of, 270;
structure of, 263.
Pupa, 189;
cross-section of body of, honey-bee, *191.
Pupation, 189.
Purpura saxicola, *248.
Pygopodes, 343.
Python, 324.
Quail, 350.
Querquedula discors, 347.
Rabbits, 390.
Radiolaria, 80.
Rail, Carolina, 349.
Raja erinacea, 280, *281.
Raja lÆvis, 281.
Rana catesbiana, 299.
Rana palustris, 300.
Rana sylvatica, 300.
Rangifer caribou, 396.
Raptores, 351.
RatitÆ, 341.
Rats, 391.
Rattlesnake poison-fangs, *324.
Rattlesnakes, 321.
Rattles of rattlesnake, *223.
Reefs, coral, 106.
Reindeer, 396.
Remora, *287.
Remoropsis brachyptera, *287.
Root-cage, 460.
Reptiles, body form and organization of, 309;
classification of, 312;
life-history of, 312;
structure of, 310.
Reptilia, 303.
Resemblance, protective, 326.
Rheas, 343.
Road-runner, 354.
Robber-ant, 225.
Robin, Western, *368.
Rock-bass, 282.
Rock-crab, *153.
Rock-dove, 351.
Rodents, 390.
Rosalina varians, *81.
Rotifer sp., *143.
Round worms, 140.
Ruminants, 395.
Sacculina, 67, *418.
Sage-hen, 350.
Salamander, red-backed, 297;
tiger, *292.
Salamanders, 297.
Salmo irideus, *283.
Salmon, king, 284.
Sand-dollar, 124.
Sand-pipers, 345.
Sanninoidea existiosa, *212.
Sap-sucker, downy, 355;
hairy, 355.
Saw-fish, 281.
Sayornis nigricans, nest and eggs of, *340.
Scale insect, red-orange, *198.
Scale insects, 198.
Scale rose, *198.
Scales of wings of LycÆna, *206;
wing of Monarch butterfly, *174.
Scallops, 246.
Scalops aquaticus, 391.
Scaphiopus, 300.
Sceloporus, 317.
Sciuropterus volans, 391.
Sciurus carolinensis, 391.
Sciurus hudsonicus, 391.
< i>Sciurus ludovicianus, 391.
Scolopendra sp., 228, 229.
Scorpion, *230.
Scorpions, 229.
Scotiaptex cinera, 353.
Screech-owl, *352, 353.
Scutigera forceps, *228.
Scyphozoa, 97, 101.
Sea anemones, 92, 102, *103.
Sea cucumber, *125.
Sea-cucumbers, 108, 121, 124.
Sea-fan, 107.
Sea-feather, 106.
Sea-horse, *285.
Sea-lamprey, 279.
Sea-lily, 118.
Sea-pen, 106.
Sea-shells, 252.
Sea-slugs, 255.
Sea-snakes, 325.
Sea-squirt, *261.
Sea-turtles, 315.
Sea-urchin, *114;
structure of, 113.
Sea-urchins, 108, 121, 123.
Seals, 397.
Selection, artificial, 409;
natural, 406.
Sembling of insects, 176.
Sepias, 256.
Setting-board for butterflies, *466, 467.
Shark, basking, 270, 280;
hammer-headed, 280;
man-eating, 280.
Sharks, 280.
Shearwaters, 345.
Sheep-fluke, 138.
Sheep, Rocky Mt., *383, 397.
Shipworm, 251.
Shoveller, 347.
Shrews, 391.
Shrimp, 151, 152.
Silk-worm, anatomy of, *178.
Siphonophore, 98.
Siren, 297, 298.
Sistrurus, 322.
Skate, barn-door, 281;
common, 280, *281.
Skates, 280.
Skeleton of coral, 285.
Tadpole, 55.
Tadpoles, *296.
TÆnia solium, 139.
Tapeworm, 139.
Teal, blue-winged, 347;
green-winged, 347.
Teleostomi, 282.
Tell-tale, 349.
Teredo, 251.
Tern, 194.
Terns, 345.
Terrapin, diamond-back, 314;
red-bellied, 314;
yellow-bellied, 314.
Testudo sp., *315.
Tetragnatha sp., *233.
Thalarctos maritimus, 398.
Thamnophis sp., life of, 307;
structure of, 303.
Thamnophis parietalis, *320.
TheridiÆ, 235.
Therioplectes sp., cornea of compound eye of, *186.
ThomisidÆ, 235.
Thrasher, sickle-billed, *371.
Thrush, russet-backed, *363.
Thymallus signifer, 284.
Ticks, 229.
Tiger-beetles, 209.
Toad, cellular structure of, 40;
development of, 55;
garden, dissection of, 5;
horned, 317;
skeleton of, *11.
Toads, 299, 300.
Torpedo, 281.
Tortoise, Galapagos giant, *315.
Tortoises, 313.
Tortoise-shell, 315.
Totanus melanoleucus, 349.
Trachea, *184.
Tree-frogs, 300.
Tree-toads, 300.
Trepang, 124.
Trichina, 140.
Trichina spiralis, 141, *141.
Trichinosis, 141.
Triopha modesta, *254.
Tripoli rock, 82.
Triton, green, 297.
Trochilus colubris, 356;
nest and eggs of, *357.
Trout, rainbow, *283.
Tumble bugs, 209.
Turdus ustulaius, *363.
Turkeys, wild, 350.
Turtle, green, 315;
hawk-bill, 315;
logger-head, 315.
Turtle-dove, 351.
Turtles, 313.
Tympanuchus americanus, 350.
Tyroglyphus siro, *230.
Ungulata, 393.
Unio sp., life-history and habits of, 243;
structure of, 239.
Uria troile californica, *344.
Ursus americanus, 398.
Ursus horribilis, 398.
Varanus niloticus, 318.
Variation, 406.
Variety, 69.
Venation of wings of insects, 174;
of wings of Monarch butterfly, *175.
Venus mercenaria, 247.
Vermes, 127;
life-history and habits of, 132;
classification of, 135.
Vertebrate, defined, 30;
brains of, 376;
eye of, *379.
Vertebrates, 259;
structure of, 259.
VespidÆ, 217.
Vinegar-eel, 140, *140.
Viper, 324;
blowing, 321.
Vipera cerasta, 324.
Vorticella sp., *76.
Vorticella, structure and life of, 75.
Vulpes pennsylvanicus, 398.
Walking-stick, 193, 194.
Wapiti, *394.
Wasps, 212;
digger, 217;
solitary, 217.
Water-beetle, predaceous, 210.
Water-beetles, 206.
Water-boatman, *199.
Water-boatmen, 197.
Water-flea, 148, *149.
Water-dog, 298.
Water-snake, 320.
Water-strider, 197, 199, *199.
Water tiger, 212, *214.
Weevils, 209.
Whalebone, 393.
Whales, 393.
Wheel-animalcule, *143.
Whip-poor-will, 356.
Whitefish, 284.
Wild-cat, 398.
Wings of Monarch butterfly showing venation, *175.
Wolf, 398.
Woodchuck, 391.
Wood-duck, 347.
Wood-frog, 300.
Wood-lice, 150.
Woodpecker, California, 356;
ivory-billed, 355;
red-headed, 355.
Woodpeckers, 354.
Wood-rat, 391.
Worm, army, *211.
Worms, 127;
life-history and habits of, 133;
classification of, 135;
marine, *134.
Xiphias gladius, 285.
Yellow-hammer, *355.
Yellow-jackets, 217.
Yellow-shank, 349.
Zenaidura macroura, 351.
Zoogeography, 436.
Zooids, 98.
Zoology, a first course in, 3;
defined, 3;
divisions of, 2;
systematic, defined, 3.
Zoophytes, 92.

[1] This is true if a strictly logical treatment of the subject is held to. As a matter of fact, it is often of advantage to begin with, or at least to take up from the beginning in connection with the indoor work, some field-work, such as the collecting and classifying of insects and the observation of their metamorphosis. As most schools begin work in the fall, advantage must be taken of the favorable opportunities for field-work at the beginning of the year. These opportunities are of course much less favorable in the winter.[2] The classification of animals used in this book is that adopted in Parker and Haswell's "Text-book of Zoology" (2 vols., 1897, Macmillan Co.). Exception is made in the case of the worms, which are considered as a single branch, Vermes, instead of as several distinct branches.[3] Zoology is formed from two Greek words: zoon, meaning animal, and logos, meaning discourse.[4] The lesser group called variety, or subspecies, we may leave out of consideration for the present.[5] Some species of animals are not represented by male individuals: and in some all the individuals are hermaphrodites, as explained in chapter XIV.[6] Each of these higher groups has a proper name composed of a single word. In the case of no group except the species is a name-word ever duplicated. Each genus, family, order, or higher group has a name-word peculiar to it, and belonging to it alone.[7] In some Protozoa a number of similar cells temporarily unite to form a colony, but each cell may still be regarded as an individual animal.[8] The author recognizes the untenability of the group Vermes as a group co-ordinate with the other branches of the animal kingdom, and that "Vermes" has been discarded in modern text-books. But because of the very scant consideration which can be given the various kinds of worm-like animals the course of the older text-books will be followed, and all of the worm-like animals, as far as referred to in this book, be considered under the group name Vermes.[9] There are in many forms a few internal projections from the exterior cuticle which act as internal skeletal pieces.[10] The labrum differs from the other mouth-parts in not being composed of a pair of body appendages; it is simply a fold or flap of the skin of the head.[11] A Text-book of Zoology, Parker & Haswell, 1897.[12] The Cambridge Natural History, vol. V, 1895, vol. VI, 1899.[13] A Manual for the Study of Insects, J. H. and A. B. Comstock, 1897.[14] It has been shown by experiment that the winged individuals, which are able to leave the old food-plant and scatter over new plants, do not appear until the food-supply begins to run short. At the insectary of Cornell University ninety-four successive generations of wingless individuals were bred, by taking care to provide a constantly abundant supply of food. This experiment was continued for more than four years.[15] The animals included by some zoologists in the single class Pisces, are held by other zoologists to constitute three distinct classes, thus making a subdivision of the branch into ten classes.[16] The author wishes to call the attention of teacher and student to the plan (referred to in the Preface, page v) adopted in writing the directions for the dissections. The sequence of the references to the various organs depends on the actual course of the dissection, and not upon the association of organs in systems. And the directions are so much condensed that they are hardly more than a means of orienting the student, leaving him to work out independently, or by the aid of more detailed accounts (sometimes specifically referred to), the details of the dissection.[17] By many zoologists the lizards and snakes are held to form two distinct orders, Lacertilia and Ophidia.[18] One of the most unfortunate and conspicuous examples of this slaughter is the partial extermination of the song-birds of Japan in the interests of European milliners. To meet their demands the country people used birdlime throughout the woods with disastrous effectiveness, as shown in the present exceeding scarcity of birds and the abundance of insect pests.[19] Oysters are hermaphroditic, each individual producing both sperm- and egg-cells.[20] Jordan and Kellogg's "Animal Life," 1900, p. 274.[21] The following directions for making skins of mammals were written for this book by Mr. W. K. Fisher of Stanford University, an experienced collector.