having the form of the body fish-like, the skin naked, and only the forelimbs developed.

CHELONIA. An order of Reptiles including the Turtles, Tortoises, &c. CIRRIPEDES.-An order of Crustaceans including the Barnacles and Acornshells. Their young resemble those of many other Crustaceans in form; but when mature they are always attached to other objects, either directly or by means of a stalk, and their bodies are enclosed by a calcareous shell composed of several pieces, two of which can open to give issue to a bunch of curled, jointed tentacles, which represent the limbs. Coccus.-The genus of Insects including the Cochineal. In these the male is a minute, winged fly, and the female generally a motionless, berrylike mass.

COCOON.-A case usually of silky material, in which insects are frequently enveloped during the second or resting-stage (pupa) of their existence. The term " cocoon-stage is here used as equivalent to "pupa-stage." CELOSPERMOUS.-A term applied to those fruits of the Umbelliferæ which have the seed hollowed on the inner face.

COLEOPTERA.-Beetles, an order of Insects, having a biting mouth and the first pair of wings more or less horny, forming sheaths for the second pair, and usually meeting in a straight line down the middle of the back. COLUMN.-A peculiar organ in the flowers of Orchids, in which the stamens, style and stigma (or the reproductive parts) are united.

COMPOSITÆ or COMPOSITOUS PLANTS.-Plants in which the inflorescence consists of numerous small flowers (florets) brought together into a dense head, the base of which is enclosed by a common envelope. (Examples, the Daisy, Dandelion, &c.)

CONFERVÆ. The filamentous weeds of fresh water.

CONGLOMERATE.-A rock made up of fragments of rock or pebbles, cemented together by some other material.

COROLLA. The second envelope of a flower, usually composed of coloured, leaf-like organs (petals), which may be united by their edges either in the basal part or throughout.

CORRELATION. The normal coincidence of one phenomenon, character, &c., with another.

CORYMB.-A bunch of flowers in which those springing from the lower part of the flower stalk are supported on long stalks so as to be nearly on a level with the upper ones.

COTYLEDONS.-The first or seed-leaves of plants.

CRUSTACEANS.-A class of articulated animals, having the skin of the body generally more or less hardened by the deposition of calcareous matter, breathing by means of gills. (Examples, Crab, Lobster, Shrimp, &c.) CURCULIO. The old generic term for the Beetles known as Weevils, characterised by their four-jointed feet, and by the head being produced into a sort of beak, upon the sides of which the antennæ are inserted. CUTANEOUS. Of or belonging to the skin.

DEGRADATION.-The wearing down of land by the action of the sea or of meteoric agencies.

DENUDATION. The wearing away of the surface of the land by water. DEVONIAN SYSTEM or formation.-A series of Palæozoic rocks, including the Old Red Sandstone.

DICOTYLEDONS OR DICOTYLEDONOUS PLANTS.-A class of plants characterised by having two seed-leaves, by the formation of new wood between the bark and the old wood (exogenous growth) and by the reticulation of the veins of the leaves. The parts of the flowers are generally in multiples of five.

DIFFERENTIATION.-The separation or discrimination of parts or organs which in simpler forms of life are more or less united.

DIMORPHIC.-Having two distinct forms.-Dimorphism is the condition of the appearance of the same species under two dissimilar forms. DIŒCIOUS. Having the organs of the sexes upon distinct individuals. DIORITE.-A peculiar form of Greenstone.

DORSAL. Of or belonging to the back.

EDENTATA.-A peculiar order of Quadrupeds, characterised by the absence of at least the middle incisor (front) teeth in both jaws. (Examples, the Sloths and Armadillos.)

ELYTRA. The hardened fore-wings of Beetles, serving as sheaths for the membranous hind-wings, which constitute the true organs of flight. EMBRYO. The young animal undergoing development within the egg or womb.

EMBRYOLOGY.-The study of the development of the embryo.
ENDEMIC.-Peculiar to a given locality.

ENTOMOSTRACA.-A division of the class Crustacea, having all the segments of the body usually distinct, gills attached to the feet or organs of the mouth, and the feet fringed with fine hairs. They are generally of small size.

EOCENE. The earliest of the three divisions of the Tertiary epoch of geologists. Rocks of this age contain a small proportion of shells identical with species now living.

EPHEMEROUS INSECTS.—Insects allied to the May-fly.

FAUNA. The totality of the animals naturally inhabiting a certain country or region, or which have lived during a given geological period.

FELIDE.-The Cat-family.

FERAL. Having become wild from a state of cultivation or domestication. FLORA. The totality of the plants growing naturally in a country, or during a given geological period.

FLORETS.-Flowers imperfectly developed in some respects, and collected into a dense spike or head, as in the Grasses, the Dandelion, &c. FŒTAL. Of or belonging to the fœtus, or embyro in course of develop

ment.

FORAMINIFERA.-A class of animals of very low organisation, and generally of small size, having a jelly-like body, from the surface of which delicate filaments can be given off and retracted for the prehension of external objects, and having a calcareous or sandy shell, usually divided into chambers, and perforated with small apertures.

FOSSILIFEROUS.-Containing fossils.

FOSSORIAL. Having a faculty of digging. The Fossorial Hymenoptera are a group of Wasp-like Insects, which burrow in sandy soil to make nests for their young.

FRENUM (pl. FRENA).-A small band or fold of skin.

FUNGI (sing. FUNGUS).—A class of cellular plants, of which Mushrooms, Toadstools, and Moulds, are familiar examples.

FURCULA. The forked bone formed by the union of the collar-bones in many birds, such as the common Fowl.

GALLINACEOUS BIRDS.-An order of Birds of which the common Fowl, Turkey, and Pheasant, are well-known examples.

GALLUS. The genus of birds which includes the common Fowl.

GANGLION.-A swelling or knot from which nerves are given off as from a

centre.

GANOID FISHES.-Fishes covered with peculiar enamelled bony scales. Most of them are extinct.

GERMINAL VESICLE.-A minute vesicle in the eggs of animals, from which the development of the embyro proceeds.

GLACIAL PERIOD.-A period of great cold and of enormous extension of ice upon the surface of the earth. It is believed that glacial periods have occurred repeatedly during the geological history of the earth, but the term is generally applied to the close of the Tertiary epoch, when nearly the whole of Europe was subjected to an arctic climate. GLAND.-An organ which secretes or separates some peculiar product from the blood or sap of animals or plants.

GLOTTIS. The opening of the windpipe into the œsophagus or gullet. GNEISS.-A rock approaching granite in composition, but more or less laminated, and really produced by the alteration of a sedimentary deposit after its consolidation.

GRALLATORES.-The so-called Wading-birds (Storks, Cranes, Snipes, &c.), which are generally furnished with long legs, bare of feathers above the heel, and have no membranes between the toes.

GRANITE. A rock consisting essentially of crystals of felspar and mica in a mass of quartz.

HABITAT.-The locality in which a plant or animal naturally lives. HEMIPTERA.—An order or sub-order of Insects, characterised by the possession of a jointed beak or rostrum, and by having the fore-wings horny in the basal portion and membranous at the extremity, where they cross each other. This group includes the various species of Bugs. HERMAPHRODITE.-Possessing the organs of both sexes. HOMOLOGY.-That relation between parts which results from their development from corresponding embryonic parts, either in different animals, as in the case of the arm of man, the fore-leg of a quadruped, and the wing of a bird; or in the same individual, as in the case of the fore and hind legs in quadrupeds, and the segments or rings and their appendages of which the body of a worm, a centipede, &c., is composed. The latter is called serial homology. The parts which stand in such a relation to each other are said to be homologous, and one such part or organ is

called the homologue of the other. In different plants the parts of the flower are homologous, and in general these parts are regarded as homologous with leaves.

HOMOPTERA.-An order or sub-order of Insects having (like the Hemiptera) a jointed beak, but in which the fore-wings are either wholly membranous or wholly leathery. The Cicada, Frog-hoppers, and

Aphides, are well-known examples.

HYBRID. The offspring of the union of two distinct species.

Bees and

HYMENOPTERA.-An order of Insects possessing biting jaws and usually
four membranous wings in which there are a few veins.
Wasps are familiar examples of this group.
HYPERTROPHIED.-Excessively developed.

ICHNEUMONIDE.-A family of Hymenopterous insects, the members of which lay their eggs in the bodies or eggs of other insects.

IMAGO. The perfect (generally winged) reproductive state of an insect. INDIGEENS.-The aboriginal animal or vegetable inhabitants of a country or region.

INFLORESCENCE.-The mode of arrangement of the flowers of plants. INFUSORIA. A class of microscopic Animalcules, so called from their having originally been observed in infusions of vegetable matters. They consist of a gelatinous material enclosed in a delicate membrane, the whole or part of which is furnished with short vibrating hairs (called cilia), by means of which the animalcules swim through the water or convey the minute particles of their food to the orifice of the mouth. INSECTIVOROUS.-Feeding on Insects.

INVERTEBRATA, or INVERTEBRATE ANIMALS.-Those animals which do not possess a backbone or spinal column.

LACUNA.-Spaces left among the tissues in some of the lower animals, and serving in place of vessels for the circulation of the fluids of the body. LAMELLATED.-Furnished with lamellæ or little plates. LARVA (pl. LARVÆ).—The first condition of an insect at its issuing from the egg, when it is usually in the form of a grub, caterpillar, or maggot. LARYNX.-The upper part of the windpipe opening into the gullet. LAURENTIAN.--A group of greatly altered and very ancient rocks, which

is greatly developed along the course of the St. Laurence, whence the name. It is in these that the earliest known traces of organic bodies have been found. LEGUMINOSA.-An order of plants represented by the common Peas and Beans, having an irregular flower in which one petal stands up like a wing, and the stamens and pistil are enclosed in a sheath formed by two other petals. The fruit is a pod (or legume).

LEMURIDE.-A group of four-handed animals, distinct from the Monkeys and approaching the Insectivorous Quadrupeds in some of their characters and habits. Its members have the nostrils curved or twisted, and a claw instead of a nail upon the first finger of the hind hands. LEPIDOPTERA.-An order of Insects, characterised by the possession of a spiral proboscis, and of four large more or less scaly wings. It includes the well-known Butterflies and Moths.

LITTORAL.—Inhabiting the seashore.

LOESS.-A marly deposit of recent (Post-Tertiary) date, which occupies a great part of the valley of the Rhine.

MALACOSTRACA.—The higher division of the Crustacea, including the ordinary Crabs, Lobsters, Shrimps, &c., together with the Woodlice and Sand-hoppers.

MAMMALIA. The highest class of animals, including the ordinary hairy quadrupeds, the Whales, and Man, and characterised by the production of living young which are nourished after birth by milk from the teats (Mamma, Mammary glands) of the mother. A striking difference in embryonic development has led to the division of this class into two great groups; in one of these, when the embryo has attained a certain stage, a vascular connection, called the placenta, is formed between the embryo and the mother; in the other this is wanting, and the young are produced in a very incomplete state. The former, including the greater part of the class, are called Placental mammals; the latter, or Aplacental mammals, include the Marsupials and Monotremes (Ornithorhynchus).

MAMMIFEROUS.—Having mammæ or teats (see MAMMALIA).

MANDIBLES, in Insects.-The first or uppermost pair of jaws, which are generally solid, horny, biting organs. In Birds the term is applied to both jaws with their horny coverings. In Quadrupeds the mandible is properly the lower jaw.

MARSUPIALS. An order of Mammalia in which the young are born in a very incomplete state of development, and carried by the mother, while sucking, in a ventral pouch (marsupium), such as the Kangaroos, Opossums, &c. (see MAMMALIA).

MAXILLÆ, in Insects.-The second or lower pair of jaws, which are com posed of several joints and furnished with peculiar jointed appendages called palpi, or feelers.

MELANISM. The opposite of albinism; an undue development of colouring material in the skin and its appendages.

METAMORPHIC ROCKS.-Sedimentary rocks which have undergone alteration, generally by the action of heat, subsequently to their deposition aud consolidation.

MOLLUSCA.--One of the great divisions of the Animal Kingdom, including those animals which have a soft body, usually furnished with a shell, and in which the nervous ganglia, or centres, present no definite general arrangement. They are generally known under the denomination of "shell-fish;" the cuttle-fish, and the common snails, whelks, oysters, mussels, and cockles, may serve as examples of them.

MONOCOTYLEDONS, or MONOCOTYLEDONOUS PLANTS.-Plants in which the seed sends up only a single seed-leaf (or cotyledon); characterised by the absence of consecutive layers of wood in the stem (endogenous growth), by the veins of the leaves being generally straight, and by the parts of the flowers being generally in multiples of three. (Examples, Grasses, Lilies, Orchids, Palms, &c.)

MORAINES.-The accumulations of fragments of rock brought down by glaciers.

MORPHOLOGY.-The law of form or structure independent of function.