ranked so high as the mammal that brings forth its young alive, and even then, by a special organisation, suckles them during months with assiduous care. But on such distinctions we need not dwell. They were made long before observation had shaped itself into systems of science, and are patent alike to the learned and the unlearned. This dictum, therefore, the zoologist lays down, that the lower a creature is in the scale of being, the more its individual parts resemble each other (vegetative repetition); and the higher it is, when, instead of several functions being performed by the same organ, each function, be it of nutrition, reproduction, or sensation, is performed by an organ specially devoted to it.

This brings us to the classification of the zoologist; and in comparing the Past with the Present Life of the Globe, the paleontologist requires to invent no new system or scheme of arrangement. One plan and design runs through the whole of animated nature; and though species and genera, and even whole families, have died out, and others have taken their places-and this has been repeated again and again—still have all the successive incomers been constructed upon the same plan, and designed to perform analogous functions. The classification of the paleontologist is therefore the same as that of the zoologist, with the exception of such extinctions as fill up the gaps that exist between conterminous genera, and render more compact and harmonious, if we may so speak, the grand scheme of terrestrial vitality. The following outline of the animal kingdom will render more intelligible the comparisons we have to institute between the past and the present-between the forms that now live and act, and those that have become extinct and been converted into stone thousands of ages ago :—

VERTEBRATA,

Or animals with back-bone and bony skeleton, and comprehending
MAMMALIA, AVES, REPTILIA, and PISCES.

I. MAMMALIA, or Sucklers, subdivided into Placental and Aplacental. 1. PLACENTAL, bringing forth mature young.

BIMANA (Two-handed)-Man.

QUADRUMANA (Four-handed)--Monkeys, Apes, Lemurs.
CHEIROPTERA (Hand-winged)—Bats, Vampyre-bats, Fox-bats.
INSECTIVORA (Insect-eaters)-Mole, Shrew, Hedgehog, Banxring.
CARNIVORA (Flesh-eaters)-Dog, Wolf, Tiger, Lion, Badger, Bear.
PINNIPEDIA (Fin-footed) Seals, Walrus.

RODENTIA (Gnawers)—Hare, Beaver, Rat, Squirrel, Porcupine.

EDENTATA (Toothless)-Ant-eater, Armadillo, Pangolin, Sloth.
RUMINANTIA (Cud-chewers)—Camel, Llama, Deer, Goat, Sheep, Ox.
SOLIDUNGULA (Solid-hoofs)-Horse, Ass, Zebra, Quagga.

PACHYDERMATA (Thick-skins)—Elephant, Hippopotamus, Rhinoceros.
CETACEA (Whales)—Whale, Porpoise, Dolphin, Lamantin.

2. APLACENTAL, bringing forth immature young.

MARSUPIALIA (Pouched)-Kangaroo, Opossum, Pouched Wolf, &c. MONOTREMATA (One-vented)—Ornithorhynchus, Porcupine ant-eaters.

II. AVES, or BIRDS.

RAPTORES (Seizers)-Eagles, Falcons, Hawks, Owls, Vultures.
INSESSORES (Perchers)—Jays, Crows, Finches, Sparrows, Thrushes, &c.
SCANSORES (Climbers)-Woodpeckers, Parrots, Cockatoos, &c.
COLUMBE (Pigeons)-Common Dove, Turtle Dove, Ground Dove.
RASORES (Scrapers)-Barnfowl, Partridge, Grouse, Pheasant.

CURSORES (Runners)—Ostrich, Emeu, Apteryx.
GRALLATORES (Waders)-Rails, Storks, Cranes, Herons.

NATATORES (Swimmers)-Divers, Gulls, Ducks, &c.

III. REPTILIA, subdivided into Reptiles Proper and Batrachians.

1. REPTILES PROPER.

CHELONIA (Tortoises)- Turtles, Tortoises.

LORICATA (Covered with Scutes)-Crocodile, Gavial, Alligator.
SAURIA (Lizards)—Lizard, Iguana, Chameleon.

OPHIDIA (Serpents)-Vipers, Snakes, Boas, &c.

2. BATRACHIANS, or FROGS.

ANOURA (Tail-less)-Toad, Frog, Tree-frog.
URODELA (Tailed)-Siren, Triton, Salamander.
APODA (Footless)-Lepidosiren, Blindworm.

IV. PISCES, or FISHES.

SELACHIA (Cartilaginous)—Chimæra, Sharks, Sawfish, Rays.

GANOIDEA (Enamel-scales)—Amia, Bony-pike, Sturgeon.

TELEOSTIA (Perfect-bones)-Eels, Salmon, Herring, Cod, Pike, &c.
CYCLOSTOMATA (Circle-mouths)-Lamprey.

LEPTOCARDIA (Slender-hearts) —Amphioxus.

INVERTEBRATA,

Or animals void of back-bone and bony skeleton, and comprehending ARTICULATA, MOLLUSCA, RADIATA, and PROTOZOA.

I. ARTICULATA, subdivided into Articulates and Vermes.

1. ARTICULATA, or Jointed Animals Proper.

INSECTA (Insects)-Beetles, Butterflies, Flies, Bees.
MYRIAPODA (Many-feet)-Scolopendra, Centipedes.
ARACHNIDA (Spiders)-Spiders, Scorpions, Mites.

CRUSTACEA (Crust-clad)—Crayfish, Crabs, Shrimps, Woodlice.
CIRRHOPODA (Curl-feet)-Acorn-shells, Barnacles.

2. VERMES, or Worms Proper.

ANNELIDA (Small-rings)-Lobworm, and almost all the marine worms.
ROTIFERA (Wheel-bearers)--Rotifers, Hydatina.

GEPHYRIA (Intermediates-urchin-like)-Sipunculus, Echinurus.
LUMBRICINA (Earth-worms)-Earth-worms, Nais.

HIRUDINEI (Leeches)- Leeches, Branchellion.

TURBELLARIA (Turbellaries)—Planaria, Ribbon-worms.
HELMINTHES (Gut-worms)-Intestinal worms.

II. MOLLUSCA, subdivided into Mollusca and Molluscoida.

1. MOLLUSCA, or Shell-fish Proper.

CEPHALOPODA (Head-footed)-Cuttle-fish, Octopus, Calamary, Nautilus.
PTEROPODA (Wing-footed)-Clio, Hyalæa.

GASTEROPODA (Belly-footed)-Snails, Slugs, Whelks, Cowries.
ACEPHALA (Headless)--Oysters, Mussels, Cockles, Shipworms.
BRACHIOPODA (Arm-footed) - Terebratula, Lingula.

2. MOLLUSCOIDA, or Mollusc-like Animals.

TUNICATA (Coated, but Shell-less) { Biphora, Simple and Compound

POLYZOA (Compound animals) Į

or

BRYOZOA (Moss-like animals),

Ascidians.

Flustra, Eschara, Plumatella, &c.

III. RADIATA, or ZOOPHYTES-Ray-like Animals. ECHINODERMATA (Urchin-skinned)-Sea-urchins, Star-fishes. ACALEPHA (Sea-nettles)-Jelly-fish, Beroës.

POLYPI (Many-feet)-Coral animals, Sea-anemones, Hydras.

IV. PROTOZOA, or LOWEST-LIFE-Globular Animals. INFUSORIA (Infusories)-Monads, Volvoces, Vorticella. PORIFERA (Pore-bearers)-Sponges, Fresh-water Sponges. RHIZOPODA (Root-footed)-Amoeba, Polythalamia (Foraminifera).

Throwing, as in the case of the vegetable world, these great groups into diagrammatic form, we have first the

Protozoa-the sponges, foraminifera, and infusorial animal

cules-which, half-plant half-animal, stand, as it were, on the verge of organised existence. Restricted to the waters, rooted as sponges to the sea-bed, appearing as infusoria (we cannot tell how) in stagnant and putrid waters, or thronging in inconceivable numbers as foraminiferæ alike the shallow estuary and the profoundest ocean-depth, their office seems to be the reconversion of organic matter from ultimate decay, and the reconstruction of mineral matter from a state of solution and diffusion. Mere gelatinous specks or glairy films, encased in or encasing some horny, flinty, or limy framework, they constitute the food of many of the lower orders, though their function, on the whole, is

mainly formative or geological. As the calcareous muds of