CHAPTER LIX

ZOOLOGY At the very outset of his zoological studies the reader will find that the doctors still differ as to the best and most scientifically logical system to be employed in classification. So important is it that the connotation and denotation of every zoological designation should be definite, that Sir Edwin Ray Lankester devotes the title article ZOOLOGY (Vol. 28, p. 1022) mainly to a discussion of systems of classification, and besides there is a separate article ZOOLOGICAL NOMENCLATURE (Vol. 28, p. 1021) by P. Chalmers Mitchell, Secretary of the Zoological Society of London, university demonstrator in comparative anatomy and assistant to the Linacre Professor at Oxford, and adviser to the editor in the organization of the whole subject of zoology in the Britannica. The Britannica articles may be classified in three divisions: dealing with (i) _General Principles_, (ii) _Systematic_, (iii) _Natural History_. [Sidenote: General Principles] The student should read at any rate some of the general articles mentioned in the chapter on _Biology_; and these will prepare him for the difficult questions involved in the articles ZOOLOGY and ZOOLOGICAL NOMENCLATURE. Supplementary to these are the following: ANIMAL (Vol. 2, p. 48), in connection with which should be read the article PROTISTA (Vol. 22, p. 476) where the borderland between the animal and vegetable kingdoms is further discussed, and the very valuable article PROTOZOA (Vol. 22, p. 479) in which E. A. Minchin, professor of protozoology in the University of London, discusses the minute animal organisms, which in the last decade have proved immensely important in the study of parasitic diseases. In LARVAL FORMS (Vol. 16, p. 224), and METAMORPHOSIS (Vol. 18, p. 221) Prof. Adam Sedgwick, of the Imperial College of Science and Technology in London, discusses the early history of larvae and their change from larval to adult growth. The articles METAMERISM (Vol. 18, p. 215), by Sir Edwin Ray Lankester, and _Regeneration of Lost Parts_ (Vol. 23, p. 36), by P. Chalmers Mitchell, discuss the capacity for repeating parts (as in the case of the common earth worm) and for the formation of new parts to take the place of those lost by accident or injury. The article MONSTER (Vol. 18, p. 740) by Dr. Charles Creighton will be found very suggestive. [Sidenote: Protective Modifications] The eyes of most of us are shut to the wonders of the animal kingdom. We know by hearsay that the colouring of an animal or insect, brilliant and startling though it often be, is designed by nature for protection by enabling it to assimilate itself to that of its surroundings. But how many of us have taken the trouble to verify this? The articles COLOURS OF ANIMALS, _Bionomics_ (Vol. 6, p. 731), by Prof. Poulton of Oxford, and MIMICRY (Vol. 18, p. 495), by R. I. Pocock, superintendent of the Zoological Gardens in London, will suggest to the reader many objects for observation. Especially interesting in the former article is the section on the use of colour for warning and signaling. In connection with these articles, those on EGG (Vol. 9, p. 13) and FEATHER (Vol. 10, p. 224), by W. P. Pycraft, of the British Museum, may be read, and NIDIFICATION (Vol. 19, p. 666), by Prof. Alfred Newton of Cambridge University, and Hans Gadow, Strickland curator and lecturer on zoology in the University of Cambridge; especially those sections concerned with the precautions taken by the birds for protection and concealment. A very fascinating subject is discussed in the articles dealing with the distribution and movements of animal life. These are ZOOLOGICAL DISTRIBUTION (Vol. 28, p. 1002), by the well-known zoologist Richard Lydekker; MIGRATION (Vol. 18, p. 433), by Hans Gadow; and PLANKTON (Vol. 21, p. 720), by G. H. Fowler of University College, London. Reference to these articles has already been made in the chapter on _Biology_. Closely connected with them is the article on PALAEONTOLOGY (Vol. 20, p. 579), by Prof. H. F. Osborn, Columbia University and American Museum of Natural History, in which the distribution of prehistoric life is discussed; and, as will be seen from the list below, all the principal species now only found in fossil remains are described in separate articles. [Sidenote: Intelligence of Animals] The editor succeeded in getting the psychologist, Prof. C. Lloyd Morgan, of the University of Bristol, who has made a specialty of this particular subject, to write extremely illuminating articles on INSTINCT and on INTELLIGENCE IN ANIMALS (Vol. 14, pp. 648 and 680). Interesting as throwing a side light on either the instinct or intelligence of birds, is the section on their song in the article SONG (Vol. 25, p. 413). It is hardly possible to look through any of these articles, or those on mimicry and colour, above alluded to, without coming across some striking and interesting fact, as for instance, the sudden change from a divine melody to an anxious croak in the utterance of the male nightingale as soon as the brood is hatched. These articles will be read for their great interest by many who do not intend systematically to pursue the subject of Zoology. [Sidenote: Animals in Captivity] The housing of animals in captivity is discussed in the articles AQUARIUM (Vol. 2, p. 237), by Professor G. H. Fowler, University College, London; AVIARY (Vol. 3, p. 60), by D. Seth-Smith, curator of birds to the Zoological Society of London; and ZOOLOGICAL GARDENS (Vol. 28, p. 1018), by P. Chalmers Mitchell. The first two contain some very useful hints for the care of small aquaria and aviaries; and young people who like to have aquaria at home, and are often disappointed by their failure to keep alive some of their specimens, especially larval and other surface-swimming animals, will find one of their difficulties solved. These surface-swimming animals die of exhaustion from their unaided efforts to keep off the bottom, lacking the support given in their surroundings by the natural flow of the water, native tides, and surface currents. The article describes a very simple arrangement by which this motion of the water can be simulated. Other articles which will be found very interesting are those on HIBERNATION (Vol. 13, p. 441) and on INCUBATION AND INCUBATORS (Vol. 14, p. 359). In the latter many will be surprised to note that incubators have been in use in Egypt from time immemorial under the name MAMAL. In one district of Egypt alone 90,000,000 eggs are annually hatched out in these old time incubators, of which the secret has been handed down, jealously guarded, from father to son. In the article TAXIDERMY (Vol. 26, p. 464), Montagu Browne, a practical taxidermist, deals with the artistic as well as the technical aspects of the craft. [Sidenote: Classification and Divisions] Turning to the articles of the chief divisions of the animal kingdom, the most useful arrangement will be to enumerate them in their order. As has been already said, zoologists do not yet agree as to the best system of classification; the one which is given in the Britannica is that upon which the very eminent zoologists who have contributed the special articles, agree as being the most suitable. There are two main grades. The PROTOZOA (Vol. 22, p. 479) contain the animalcules, mainly microscopic. These are the most elementary forms of life and consist of single cells. The other and more important grade is that of the METAZOA, which are built up of many cells. [Sidenote: Protozoa] The main subdivisions (called phyla) of the Protozoa are: phylum i. SARCODINA (Vol. 24, p. 208); phylum ii. MASTIGOPHORA (Vol. 17, p. 873); phylum iii. SPOROZOA (Vol. 25, p. 734); phylum iv. INFUSORIA (Vol. 14, 557). [Sidenote: Metazoa] Coming next, the Metazoa in their order are, as follows: phylum i. Porifera (see SPONGES, Vol. 25, p. 715); phylum ii. HYDROMEDUSAE or HYDROZOA (Vol. 14, pp. 135 and 171) which include aquatic animals of the coral kind; phylum iii. SCYPHOMEDUSA (Vol. 24, p. 519) which include groups of shell fish; phylum iv. ANTHOZOA (Vol. 2, p. 97) with the corals; phylum v. CTENOPHORA (Vol. 7, p. 592) including the jelly fish; phylum vi. PLATYELMIA (Vol. 21, p. 826) a group of animals in which creeping first became habitual; phylum vii. Nematoidea (see NEMATODA, Vol. 19, p. 359) which include certain kinds of worms; phylum viii. CHAETOGNATHA (Vol. 5, p. 789) an isolated class of transparent pelagic organisms; phylum ix. NEMERTINA (Vol. 19, p. 363) worm families; phylum x. MOLLUSCA (Vol. 2, p. 669) shell-bearing animals. Phylum xi. APPENDICULATA (Vol. 2, p. 220) which include the sub-phyla ROTIFERA (Vol. 23, p. 759), CHAETOPODA (Vol. 5, p. 789), and ARTHROPODA (Vol. 2, p. 673), the sub-phylum which comprises practically the whole insect family. Important articles on animals in this class are: HEXAPODA (Vol. 13, p. 418) which include the wasp, beetle, and other families; the CRUSTACEA (Vol. 7, p. 552) which cover a field wide enough to embrace species as different outwardly as lobsters, wood-lice, and minute water fleas; and ARACHNIDA (Vol. 2, p. 287) the spider family. Phylum xii. ECHINODERMA (Vol. 8, p. 871) with all the sea-urchins and star fish. Phylum xiii. VERTEBRATA (Vol. 27, p. 1047) to which man belongs as an order of a sub-class of a class of a sub-phylum. The most important sub-phylum of the Vertebrata is the Craniata (see Vol. 27, p. 1048). The sub-phyla HEMICHORDA (Vol. 13, p. 257), Urochorda (see TUNICATA, Vol. 27, p. 379), and Cephalochorda (see AMPHIOXUS, Vol. 1, p. 886) deal with the lower orders of Vertebrata. The sub-phylum Craniata comprises the following classes: class i. Pisces, see ICHTHYOLOGY (Vol. 14, p. 243) with the fishes; class ii. BATRACHIA (Vol. 3, p. 521), with the frog tribe; class iii. Reptilia (see REPTILES, Vol. 23, p. 136); and in close connection with this—class iv. Aves (see BIRD, Vol. 3, p. 959, and ORNITHOLOGY, Vol. 20, p. 299); class v. MAMMALIA (Vol. 17, p. 520) to which man belongs. Phylum xiv. MESOZOA (Vol. 18, p. 187) minute parasitic animals intermediate between the Protozoa and the Metazoa. Phylum xv. POLYZOA (Vol. 22, p. 42) aquatic animals forming colonies by budding. Phylum xvi. ACANTHOCEPHALA (Vol. 1, p. 109) including the parasitic worms. Phylum xvii. PODAXONIA (Vol. 28, p. 1023), and phylum xviii. GASTROTRICHA (Vol. 11, p. 526) minute animals living at the bottom of ponds and marshes. [Sidenote: Natural History] This is an outline of the main division of the animal kingdom in their order as now classified. The subject of zoology is so vast that the student will probably confine himself to one branch of the subject, perhaps to one small fraction of a division, of which he proposes to investigate the complete natural history. As will be seen from the list below, which is classified, the Britannica offers an immense amount of material bearing on the subject. But of course the study of any one sub-class needs a general knowledge of the foundations of zoological science, so that some acquaintance with the principles on which the animal world is classified is indispensable. As in Botany, it will be easy to see from the article on any individual animal to which family it belongs so that the young student can work back from the particular to the general and find out the whole relationship of the subject in which he is interested by reference to the “systematic” article. LIST OF ARTICLES IN THE ENCYCLOPAEDIA BRITANNICA ON ZOOLOGY (For biographies of Zoologists, see the end of the chapter on Biology) =Zoology: General= Abomasum Acetabulum Animal Aquarium Aviary Beak Breeds and Breeding Carapace Colours of Animals Comparative Anatomy Conch Contractile Vacuole Crepuscular Dew-claw Dewlap Dorsiventral Dredge Egg Feather Grub Herd Hibernation Incubation and Incubators Instinct Intelligence in Animals Karyogamy Larval Forms Meganucleus Membranelle Metamerism Metamorphosis Micronucleus Migration Mimicry Mongrel Monster Moult Nest Nidification Plankton Proboscis Pylome Quill Regeneration of Lost Parts Sex Song (of Birds) Taxidermy Vermin Zoology Zoological Distribution Zoological Gardens Zoological Nomenclature =Zoology, Systematic=: Invertebrata Acanthocephala Acineta Actinozoa Algae Amoeba Annelida Anthozoa Appendiculata Aptera Arachnida Arcella Arthropoda Articulata Aspirotrochaceae Brachiopoda Campodea Cephalopoda Chaetognatha Chaetopoda Ciliata Coccidia Coelentera Coleoptera Crustacea Ctenophora Cystoflagellata Dendrocometes Desmoscolecida Difflugia Dinoflagellata Diptera Echinoderma Echiuroidea Ectospora Endospora Entomostraca Epistylis Filosa Flagellata Foraminifera Gastropoda Gastrotricha Gephyrea Globigerina Gnathopoda Gregarines Gymnostomaceae Haemosporidia Haplodrili Heliozoa Hemiptera Heterokaryota Hexapoda Hydromedusae Hydrozoa Hymenoptera Infusoria Kinorhyncha Labyrinthulidea Lamellibranchia Lepidoptera Malacostraca Mastigophora Medusa Mesozoa Mollusca Molluscoida Mycetozoa Myonemes Myriapoda Myzostomida Nematoda Nematomorpha Nemertina Neuroptera Nummulite Opalina Orthoptera Paramecium Pedipalpi Pelomyxa Pentastomida Peripatus Perissodactyla Phoronidea Planarians Platyelmia Polyp Polyzoa Priapuloidea Proteomyxa Protista Protogenes Protomyxa Protozoa Pseudopod Pycnogonida, or Pantopoda Radiata Radiolaria Rhizopoda Rotifera Sarcodina Scaphopoda Scyphomedusae Sipunculoidea Sponges Sporozoa Stentor Thyrostraca Thysanoptera Thysanura Trematodes Trypanosomes Vampyrella Vorticella =Zoology, Systematic=: Vertebrata Amphibia Artiodactyla Amphioxus Balanoglossus Batrachia Bovidae Caecilia Carnivora Cetacea Chaetosomatida Chiroptera Cyclostomata, or Marsipobranchii Cyprinodonts Edentata Equidae Hemichorda Hyracoidea Insectivora Marsupialia Monodelphia Monotremata Pecora Proboscidea Pterobranchia Ratitae Rodentia Ruminantia Salmon and Salmonidae Sauropsida Selachians, or Elasmobranchii Suina Tardigrada Teleostomes Tunicata Tylopoda Ungulata Vertebrata =Zoology, Natural History=: Mammals Aard-vark Aard-wolf Addax Agouti Alpaca Ant-eater Antelope Anthropoid Apes Aona Ape Argali Armadillo Ass Aurochs Avahi Aye-aye Babirusa Baboon Badger Bandicoot Bandicoot-rat Bantin Barbary Ape Bat Bear Beaver Beluga Bharal Binturong Bison Black Ape Black Buck Boar Bongo Bottlenose Whale Bronco Buck Buffalo Bushbuck Ca’ing Whale Calf Camel Capuchin Monkey Capybara Caracal Cat Catarrhine Ape Cattle Cavy Chacma Chamois Cheeta Chevrotain Chimpanzee Chinchilla Chiru Civet Clouded Leopard Coati Colugo Coyote Coypu Dasyure Deer Diana Monkey Dingo Dog Dolphin Dormouse Douroucouli Dromedary Dugong Duiker Echidna Eland Elephant Elk Ermine Eyra Fallow-deer Ferret Field-mouse Filander Flying-fox Flying Squirrel Foussa Fox Galago Galeopithecus Gaur Gayal Gelada Genet Gerbil Gerenuk Gibbon Giraffe Glutton, or Wolverine Gnu Goat Gopher Goral Gorilla Green Monkey Grison Grivet Groove-toothed Squirrel Ground-squirrel Guanaco Guenon Guereza Hamster Hare Hartebeest Hedgehog Heifer Heron Hind Hippopotamus Horse Hound Howler Humpback-whale Hunting Dog Hyena Ibex Ichneumon Indri Jackal Jaguar Jaguarondi Jennet Jerboa Jumping-hare Jumping-mouse Jumping-shrew Kangaroo Kangaroo-rat Kinkajou Kit-fox Klipspringer Koala Kudu Langur Lemming Lemur Leopard Linsang Lion Llama Loris Lynx Macaque Macrauchenia Mammalia Manati Mandrill Mangabey Manul Mare Markhor Marmoset Marmot Marshbuck Marsupial Mole Marten Merino Mink Mole Mole-rat Mole-shrew Mona Monkey Monkey Moose Mouflon Mouse Mule Muntjac Musk-deer Musk-ox Musk-rat Musk-shrew Mustang Nilgai Ocelot Octodon Okapi Opossum Orang-utan Oribi Oryx Otter Ox Paca Palla Palm-civet Panda Pangolin Panther Pariah Dog Patas Monkey Peccary Père David’s Deer Phalanger Pica Pig Pithecanthropus Erectus Platypus Pluto Monkey Pocket-gopher Pocket-mouse Polecat Pony Porcupine Porpoise Potoroo Potto Pouched-mouse Prairie-marmot Primates Proboscis-monkey Prongbuck Puma Quagga Rabbit Raccoon Raccoon-dog Ram Rat Ratel Reedbuck Reindeer Rhinoceros Rhytina River-hog Rocky-Mountain Goat Roebuck Rorqual Sable Antelope Saiga Saki Seal Serow Serval Sheep Shrew Sifaka Sirenia Skunk Sloth Snow-leopard Souslik Sperm-whale Spider-monkey Spiny Squirrel Springbuck Squirrel Squirrel Monkey Star-nosed Mole Suricate Swine Tahr Takin Tapir Tarsier Tenrec Thylacine Tiger Tiger-cat Timber-Wolf Tree Kangaroo Tree-shrew Udad, Aoudad, or Audad Uakari Vampire Vervet Vicugña Viscacha Vole Wallaby Walrus Waltzing Mouse Wanderu Wart-hog Waterbuck Water-deer Water-opossum Weasel Whale Wolf Wombat Yak Zebra =Zoology, Natural History=: Birds Albatross Auk Beccafico Bird Birds of Paradise Bittern Blackbird Blackcock Bullfinch Bunting Bustard Buzzard Canary Capercally Cassowary Chaffinch Cockatoo Cock-of-the-Rock Condor Coot Cormorant Crane Crossbill Crow Cuckoo Curassow Curlew Diver Dodo Dove Duck Eagle Eider Emeu Falcon Fieldfare Finch Flamingo Flycatcher Fowl Frigate-bird Fulmar Gadwall Gannet Gare-fowl Garganey Goatsucker Godwit Golden-eye Goldfinch Goose Gos-hawk Grackle Grebe Greenfinch Greenshank Grosbeak Grouse Guacharo Guan Guillemot Guinea Fowl Gull Harpy Harrier or Hen Harrier Hawfinch Hawk Hen Heron Hoactzin, or Hoatzin Honey-eater Honey-guide Hoopoe Hornbill Humming-bird Ibis Icterus Jabiru Jacamar Jacaná Jackdaw Jay Kakapo Kestrel Killdeer King-bird Kingfisher Kinglet Kite Kiwi, or Kiwi-Kiwi Knot Lammergeyer Lapwing Lark Linnet Loom, or Loon Lory Love-bird Lyre-bird Macaw Magpie Mallemuck Manakin Manucode Martin Megapode Merganser Mew Moa Mocking-bird Moor-hen Morillon Motmot Mouse-bird Nestor Nightingale Noddy Nonpareil Nutcracker Nuthatch Ocydrome Oriole Ornithology Orthonyx Ortolan Osprey Ostrich Ousel, or Ouzel Owl Oyster-catcher Parrot Partridge Peacock Pelican Penguin Petrel Pheasant Pica Pigeon Pipit Pitta Plover Pochard, Pockard, or Poker Pratincole Ptarmigan Puff-bird Puffin Quail Quezal, or Quesal Rail Raven Razorbill Redbreast, or Robin Redshank Redstart Redwing Rhea Rifleman-bird Roller Rook Ruff Sand-grouse Sandpiper Scaup Scoter Screamer Scrub-bird Secretary-bird Seriema, or Cariama Shearwater Sheathbill Sheld-drake Shoe-bill Shoveler Shrike Siskin Skimmer Skua Snake-bird Snipe Sparrow Spoonbill Starling Stilt, or Long-legged Plover Stork Sugar-bird Sun-bird Sun-bittern Swallow Swan Swift Tanager-bird Tapaculo Teal Tern Thrush Tinamou Titmouse Tody Toucan Touracou Tree-creeper Trogan Tropic-bird Trumpeter Turkey Turnstone Vulture Wagtail Warbler Waxwing Weaver-bird Wheatear Whitethroat Wigeon, or Widgeon Woodchuck Woodcock Woodpecker Wren Wry-neck Zosterops =Zoology, Natural History=: Reptiles Adder Alligator Alytes Amphisbaena Anaconda Asp Basilisk Boa Chameleon Cobra Cockatrice Crocodile Cryptobranchus Dragon Gecko Iguana Lizard Proteus Python Rattlesnake Reptiles Sea-serpent Snakes Sphenodon Tortoise Viper =Zoology, Natural History=: Fishes Anchovy Angler Barbel Beluga Bitterling Bleak Bream Brill Burbot Carp Cat-fish Char Chub Cichlid Coal-fish Cod Dace, Dare, or Dart Dog-fish Dory, or John Dory Eel Electric Eel File-fish and Trigger Fish Flat-fish Flounder Fluke Flying-fish Gar-fish Globe-fish Goby Goldfish Goramy, or Gouramy Grampus Grayling Gudgeon Gurnard Gwyniad Haddock Hag-fish Hair-tail Hake Halibut Hammer-Kop, or Hammerhead Herring Horse Mackerel Ichthyology Kipper Lamprey Ling Loach Lump-sucker Mackerel Mahseer, or Mahaseer Menhaden Miller’s Thumb Minnow Mormyr Mullet Muraena Murray Cod Narwhal Opah Parr Parrot-fishes Perch Pike Pike-perch Pilchard Pilot-fish Pipe-fishes Plaice Pollack Pollan Pout Ray Ribbon-fishes Roach Rudd, or Red-eye Salmon Sand-Eel Sea-horse Sea-wolf Shad Shark Sheepshead Silverfish Smelt Sole Sprat Stickleback Sturgeon Sun-fish Sword-fish Tench Trout Tunny Turbot Vendace Weever Whitebait Whitefish Whiting Wrasse =Zoology, Natural History=: Batrachians Axolotl Batrachia Frog Newt Salamander Siren Surinam Toad Tadpole Toad Tree Frog =Zoology, Natural History=: Insects Acarus Alder-fly Ant Ant Lion Aphides Bee Beetle Bird-louse Bug Butterfly and Moth Caddis-fly and Caddis-worm Caterpillar Chafer Cicada Cochineal Cockroach Cricket Cuckoo-spit Death-watch Dragon-fly Earwig Entomology Fire Brat Fire-fly Flea Fly Glow-worm Gnat Grasshopper Ground-pearl Harvest-bug Harvester Hemimerus Ichneumon-fly Insect Katydid Lacewing-fly Lantern-fly Leaf-insect Locust Louse Mantis Mantis-fly May-fly, or Ephemeridae Mosquito Moth Palmer Phylloxera Saw-fly Scale-insect Scorpion-fly Snake-fly Springtail Stick-insect Stone-fly Tarantula Termite Ticks Tsetse-fly Wasp Water-boatman Water-scorpion Weevil Wireworm =Zoology, Natural History=: Other Invertebrata Abalone Asterid Barnacle Bêche-de-Mer, or Trepang Book-scorpion Centipede Chiton Cockle Cowry Crab Crayfish Cuttle Fish Earthworm King-crab Leech Lobster Millipede Mite Mussel Nautilus Octopus Oyster Prawn Scorpion Sea-urchin Shrimp Snail Spider Starfish Tapeworms Teredo Water-flea Wood-louse Worm =Zoology, Palaeontology= Amblypoda Anclyopoda Anthracotherium Archaeopteryx Arsinoïtherium Creodonta Dinotherium Diplodocus Dryopithecus Ganodonta Glyptodon Graptolites Ichthyosaurus Iguanodon Litopterna Machaerodus Mammoth Mastodon Megatherium Multituberculata Mylodon Odontornithes Oreodon Ostracoderms, or Ostracophores Palaeontology Palaeospondylus Palaeotherium Phenacodus Phorohacos Plesiosaurus Pterodactyles Sparassodonta Tillodontia Titanotheriidae Toxodontia Trilobites